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Sample records for macroscopic polymer film

  1. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  2. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2008-12-30

    A film contains a first polymer having a plurality of hydrogen bond donating moieties, and a second polymer having a plurality of hydrogen bond accepting moieties. The second polymer is hydrogen bonded to the first polymer.

  3. Macroscopic Modeling of Polymer-Electrolyte Membranes

    Energy Technology Data Exchange (ETDEWEB)

    Weber, A.Z.; Newman, J.

    2007-04-01

    In this chapter, the various approaches for the macroscopic modeling of transport phenomena in polymer-electrolyte membranes are discussed. This includes general background and modeling methodologies, as well as exploration of the governing equations and some membrane-related topic of interest.

  4. Terahertz Science and Technology of Macroscopically Aligned Carbon Nanotube Films

    Science.gov (United States)

    Kono, Junichiro

    One of the outstanding challenges in nanotechnology is how to assemble individual nano-objects into macroscopic architectures while preserving their extraordinary properties. For example, the one-dimensional character of electrons in individual carbon nanotubes leads to extremely anisotropic transport, optical, and magnetic phenomena, but their macroscopic manifestations have been limited. Here, we describe methods for preparing macroscopic films, sheets, and fibers of highly aligned carbon nanotubes and their applications to basic and applied terahertz studies. Sufficiently thick films act as ideal terahertz polarizers, and appropriately doped films operate as polarization-sensitive, flexible, powerless, and ultra-broadband detectors. Together with recently developed chirality enrichment methods, these developments will ultimately allow us to study dynamic conductivities of interacting one-dimensional electrons in macroscopic single crystals of single-chirality single-wall carbon nanotubes.

  5. Effects of varying interfacial surface tension on macroscopic polymer lenses

    Science.gov (United States)

    Zimmerman, Charlotte; White, Mason; Baylor, Martha-Elizabeth

    2015-09-01

    We investigate macroscopic polymer lenses (0.5- to 2.5-cm diameter) fabricated by dropping hydrophobic photocurable resin onto the surface of various hydrophilic liquid surfaces. Due to the intermolecular forces along the interface between the two liquids, a lens shape is formed. We find that we can vary the lens geometry by changing the region over which the resin is allowed to spread and the surface tension of the substrate to produce lenses with theoretically determined focal lengths ranging from 5 to 25 mm. These effects are varied by changing the container width, substrate composition, and substrate temperature. We present data for five different variants, demonstrating that we can control the lens dimensions for polymer lens applications that require high surface quality.

  6. CH-π Interaction Driven Macroscopic Property Transition on Smart Polymer Surface

    Science.gov (United States)

    Li, Minmin; Qing, Guangyan; Xiong, Yuting; Lai, Yuekun; Sun, Taolei

    2015-10-01

    Life systems have evolved to utilize weak noncovalent interactions, particularly CH-π interaction, to achieve various biofunctions, for example cellular communication, immune response, and protein folding. However, for artificial materials, it remains a great challenge to recognize such weak interaction, further transform it into tunable macroscopic properties and realize special functions. Here we integrate monosaccharide-based CH-π receptor capable of recognizing aromatic peptides into a smart polymer with three-component “Recognition-Mediating-Function” design, and report the CH-π interaction driven surface property switching on smart polymer film, including wettability, adhesion, viscoelasticity and stiffness. Detailed studies indicate that, the CH-π interaction induces the complexation between saccharide unit and aromatic peptide, which breaks the initial amphiphilic balance of the polymer network, resulting in contraction-swelling conformational transition for polymer chains and subsequent dramatic switching in surface properties. This work not only presents a new approach to control the surface property of materials, but also points to a broader research prospect on CH-π interaction at a macroscopic level.

  7. CH-π Interaction Driven Macroscopic Property Transition on Smart Polymer Surface.

    Science.gov (United States)

    Li, Minmin; Qing, Guangyan; Xiong, Yuting; Lai, Yuekun; Sun, Taolei

    2015-10-29

    Life systems have evolved to utilize weak noncovalent interactions, particularly CH-π interaction, to achieve various biofunctions, for example cellular communication, immune response, and protein folding. However, for artificial materials, it remains a great challenge to recognize such weak interaction, further transform it into tunable macroscopic properties and realize special functions. Here we integrate monosaccharide-based CH-π receptor capable of recognizing aromatic peptides into a smart polymer with three-component "Recognition-Mediating-Function" design, and report the CH-π interaction driven surface property switching on smart polymer film, including wettability, adhesion, viscoelasticity and stiffness. Detailed studies indicate that, the CH-π interaction induces the complexation between saccharide unit and aromatic peptide, which breaks the initial amphiphilic balance of the polymer network, resulting in contraction-swelling conformational transition for polymer chains and subsequent dramatic switching in surface properties. This work not only presents a new approach to control the surface property of materials, but also points to a broader research prospect on CH-π interaction at a macroscopic level.

  8. Characterization of Nanostructured Polymer Films

    Science.gov (United States)

    2014-12-23

    AFRL-OSR-VA-TR-2015-0059 Characterization of Nanostructured Polymer Films RODNEY PRIESTLEY TRUSTEES OF PRINCETON UNIVERSITY Final Report 12/23/2014...Report 3. DATES COVERED (From - To) 06/01/2012-08/31/2014 4. TITLE AND SUBTITLE Characterization of Nanostructured Polymer Films 5a. CONTRACT...properties is due to the film morphology, i.e., the films are nanostructured . The aim of this proposal was to understand the mechanism of film formation and

  9. Anisotropic magnetothermopower in ferromagnetic thin films grown on macroscopic substrates

    Energy Technology Data Exchange (ETDEWEB)

    Jayathilaka, P.B. [Department of Physical Sciences, Faculty of Applied Sciences, Rajarata University of Sri Lanka, Mihintale (Sri Lanka); Belyea, D.D. [Department of Physics, University of South Florida, 4202 East Fowler Avenue, Tampa, FL 33620 (United States); Fawcett, T.J. [College of Engineering, University of South Florida, 4202 East Fowler Avenue, Tampa, FL 33620 (United States); Miller, Casey W. [School of Chemistry and Materials Science, Rochester Institute of Technology, 85 Lomb Memorial Drive, Rochester, NY 14623 (United States)

    2015-05-15

    We report observing the anisotropic magnetothermopower in a variety of ferromagnetic thin films grown on macroscopic substrates. These measurements were enabled by eliminating spurious signals related to the Anomalous Nernst Effect by butt-mounting the sample to the heat source and sink, and appropriate positioning of electrical contacts to avoid unwanted thermal gradients. This protocol enabled detailed measurements of the magnetothermopower in the transverse and longitudinal configurations. This may enable Spin Seebeck Effect studies in the in-plane geometry. - Highlights: • Unintentional thermal gradients along surface normal mitigated via butt-mounting. • Longitudinal/transverse magnetothermopower measured on many systems. • Anomalous Nernst Effect reduced. • Importance of magnetic anisotropy identified with angle-dependent measurements.

  10. Making waves in a photoactive polymer film

    Science.gov (United States)

    Gelebart, Anne Helene; Jan Mulder, Dirk; Varga, Michael; Konya, Andrew; Vantomme, Ghislaine; Meijer, E. W.; Selinger, Robin L. B.; Broer, Dirk J.

    2017-06-01

    Oscillating materials that adapt their shapes in response to external stimuli are of interest for emerging applications in medicine and robotics. For example, liquid-crystal networks can be programmed to undergo stimulus-induced deformations in various geometries, including in response to light. Azobenzene molecules are often incorporated into liquid-crystal polymer films to make them photoresponsive; however, in most cases only the bending responses of these films have been studied, and relaxation after photo-isomerization is rather slow. Modifying the core or adding substituents to the azobenzene moiety can lead to marked changes in photophysical and photochemical properties, providing an opportunity to circumvent the use of a complex set-up that involves multiple light sources, lenses or mirrors. Here, by incorporating azobenzene derivatives with fast cis-to-trans thermal relaxation into liquid-crystal networks, we generate photoactive polymer films that exhibit continuous, directional, macroscopic mechanical waves under constant light illumination, with a feedback loop that is driven by self-shadowing. We explain the mechanism of wave generation using a theoretical model and numerical simulations, which show good qualitative agreement with our experiments. We also demonstrate the potential application of our photoactive films in light-driven locomotion and self-cleaning surfaces, and anticipate further applications in fields such as photomechanical energy harvesting and miniaturized transport.

  11. Nanorheology of confined polymer films

    Science.gov (United States)

    Fowler, Paul; Ilton, Mark; McGraw, Joshua D.; Dalnoki-Veress, Kari

    Liquid films with a non-uniform thickness flatten in order minimize surface energy, a process driven by surface tension and mediated by viscosity. For a viscous thin film, the time evolution of the film height profile is accurately described with lubrication theory by the capillary-driven thin film equation. Previous experiments have successfully applied the thin film equation to measure the rheological properties of polymeric liquids. Here we probe confinement effects in thin polymer films. We measure the viscosity by tracking the levelling of surface perturbations with AFM. For films with thicknesses thinner than the end-to-end distance of the molecule we observe deviations from a thin film model with bulk viscosity.

  12. Polymer film composite transducer

    Science.gov (United States)

    Owen, Thomas E.

    2005-09-20

    A composite piezoelectric transducer, whose piezoeletric element is a "ribbon wound" film of piezolectric material. As the film is excited, it expands and contracts, which results in expansion and contraction of the diameter of the entire ribbon winding. This is accompanied by expansion and contraction of the thickness of the ribbon winding, such that the sound radiating plate may be placed on the side of the winding.

  13. Thin film calorimetry of polymer films

    Science.gov (United States)

    Zhang, Wenhua; Rafailovich, Miriam; Sokolov, Jonathan; Salamon, William

    2000-03-01

    Polystryene and polymethylmethacrylate films for thicknesses ranging from 50nm to 500nm using a direct calorimetric technique (Lai et al, App. Phys. Lett. 67, p9(1995)). Samples were deposited on Ni foils(2-2.5um) and placed in a high vacuum oven. Calibrated heat pulses were input to the polymer films by current pulses to the Ni substrate and temperature changes were determined from the change in Ni resistance. Pulses producing temperature jumps of 3-8K were used and signal averaging over pulses reduced noise levels enough to identify glass transitions down to 50nm. Molecular weight dependence of thick films Tg was used as a temperature calibration.

  14. Ultrathin Polymer Films, Patterned Arrays, and Microwells

    Science.gov (United States)

    Yan, Mingdi

    2002-05-01

    The ability to control and tailor the surface and interface properties of materials is important in microelectronics, cell growth control, and lab-on-a-chip devices. Modification of material surfaces with ultrathin polymer films is attractive due to the availability of a variety of polymers either commercially or by synthesis. We have developed two approaches to the attachment of ultrathin polymer films on solid substrates. In the first method, a silane-functionalized perfluorophenyl azide (PFPA-silane) was synthesized and used to covalently immobilize polymer thin films on silicon wafers. Silanization of the wafer surface with the PFPA-silane introduced a monolayer of azido groups which in turn covalently attached the polymer film by way of photochemically initiated insertion reactions. The thickness of the film could be adjusted by the type and the molecular weight of the polymer. The method is versatile due to the general C-H and/or N-H insertion reactions of crosslinker; and therefore, no specific reactive functional groups on the polymers are required. Using this method, a new type of microwell array was fabricated from covalently immobilized polymer thin films on flat substrates. The arrays were characterized with AFM, XPS, and TOF-SIMS. The second method describes the attachment of polymer thin films on solid substrates via UV irradiation. The procedure consisted of spin-coating a polymer film and irradiating the film with UV light. Following solvent extraction, a thin film remained. The thickness of the film, from a few to over a hundred nanometers, was controlled by varying solution concentration and the molecular weight of the polymer.

  15. Functional Films from Silica/Polymer Nanoparticles

    Directory of Open Access Journals (Sweden)

    Tânia Ribeiro

    2014-05-01

    Full Text Available High performance functional coatings, based on hybrid organic/inorganic materials, are being developed to combine the polymer flexibility and ease of processing with the mechanical properties and versatility of inorganic materials. By incorporating silica nanoparticles (SiNPs in the polymeric matrices, it is possible to obtain hybrid polymer films with increased tensile strength and impact resistance, without decreasing the flexural properties of the polymer matrix. The SiNPs can further be used as carriers to impart other functionalities (optical, etc. to the hybrid films. By using polymer-coated SiNPs, it is possible to reduce particle aggregation in the films and, thus, achieve more homogeneous distributions of the inorganic components and, therefore, better properties. On the other hand, by coating polymer particles with silica, one can create hierarchically structured materials, for example to obtain superhydrophobic coatings. In this review, we will cover the latest developments in films prepared from hybrid polymer/silica functional systems.

  16. Pore scale mixing and macroscopic solute dispersion regimes in polymer flows inside 2D model networks

    CERN Document Server

    D'Angelo, M V; Allain, C; Hulin, J P; Angelo, Maria Veronica D'; Auradou, Harold; Allain, Catherine; Hulin, Jean-Pierre

    2006-01-01

    A change of solute dispersion regime with the flow velocity has been studied both at the macroscopic and pore scales in a transparent array of capillary channels using an optical technique allowing for simultaneous local and global concentration mappings. Two solutions of different polymer concentrations (500 and 1000 ppm) have been used at different P\\'eclet numbers. At the macroscopic scale, the displacement front displays a diffusive spreading: for $Pe \\leq 10$, the dispersivity $l\\_d$ is constant with $Pe$ and increases with the polymer concentration; for $Pe > 10$, $l\\_d$ increases as $Pe^{1.35}$ and is similar for the two concentrations. At the local scale, a time lag between the saturations of channels parallel and perpendicular to the mean flow has been observed and studied as a function of the flow rate. These local measurements suggest that the change of dispersion regime is related to variations of the degree of mixing at the junctions. For $Pe \\leq 10$, complete mixing leads to pure geometrical di...

  17. Polymer surfaces, interfaces and thin films

    Energy Technology Data Exchange (ETDEWEB)

    Stamm, M. [Max-Planck-Institut fuer Polymerforschung, Mainz (Germany)

    1996-11-01

    Neutron reflectometry can be used in various ways to investigate surfaces, interfaces and thin films of polymers. Its potential comes mostly from the possibilities offered by selective deuteration, where a particular component can be made visible with respect to its activity at the interface. In addition the depth resolution is much better than with most other direct techniques, and details of the profiles may be resolved. Several examples will be discussed including the segment diffusion at the interface between two polymer films, the determination of the narrow interfaces between incompatible polymer blends and the development of order in thin diblock copolymer films. (author) 10 figs., 2 tabs., 38 refs.

  18. Oxygen diffusion in bilayer polymer films

    DEFF Research Database (Denmark)

    Poulsen, Lars; Zebger, Ingo; Tofte, Jannik Pentti;

    2004-01-01

    Experiments to quantify oxygen diffusion have been performed on polymer samples in which a film of poly(ethylene-co-norbornene) was cast onto a film of polystyrene which, in turn, was cast onto an oxygen-impermeable substrate. In the technique employed, the time evolution of oxygen transport...... through the film of poly(ethylene-co-norbornene) and into the polystyrene film was monitored using the phosphorescence of singlet oxygen as a spectroscopic probe. To analyze the data, it was necessary to solve Fick's second law of diffusion for both polymer films. Tractable analytical and numerical...... solutions were obtained for the problem. Moreover, the numerical solution is sufficiently general that it can be used to simulate oxygen concentration profiles in films consisting of more than two layers. Data obtained from the bilayer films yield a diffusion coefficient for oxygen in poly...

  19. Photoinduced micropattern in an azobenzene polymer film

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The micropattern observed in the amorphous azobenzene polymer film by degenerated four-wave mixing has been reported. Patterns with well-defined structures are examined with the scanning electron microscopy and the polarizing optical microscopy. It is demonstrated that the control of photoinduced micropattern in the azobenzene polymer film is possible by using appropriate polarized writing beams with total incident power exceeding a certain threshold.

  20. Macroscopic Ordering of CNTs in a Liquid Crystalline Polymer Nano-Composite by Shearing

    Science.gov (United States)

    Kalakonda, P.; Sarkar, S.; Iannacchione, G. S.; Gombos, E.; Hoonjan, G. S.; Georgiev, G.; Cebe, P.

    2012-02-01

    We present a series of complimentary experiments exploring the macroscopic alignment of carbon nanotubes (CNTs) in a liquid crystalline polymer (isotactic polypropylene - iPP) nano-composites as a function of temperature, shear, and CNT concentration. The phase behavior of iPP+CNT, studied by Modulated Differential Scanning Calorimetry, revealed the evolution of the α-monoclinic transition and its dynamics, which are dependent on CNT content and thermal treatment. These results indicate that the CNT nucleates crystal formation from the melt. Spectroscopic ellipsometry reveals a change in the optical constants that are connected to the ordering of CNTs when the iPP+CNT is sheared. This anisotropy is also exhibited in measurements of the electrical and thermal conductivities parallel and perpendicular to the shear direction. The amount of order induced into the dispersed CNTs is relatively low for these low concentration samples (< 5 wt%).

  1. Intrinsically conductive polymer thin film piezoresistors

    DEFF Research Database (Denmark)

    Lillemose, Michael; Spieser, Martin; Christiansen, N.O.

    2008-01-01

    We report on the piezoresistive effect in the intrinsically conductive polymer, polyaniline. A process recipe for indirect patterning of thin film polyaniline has been developed. Using a specially designed chip, the polyaniline thin films have been characterised with respect to resistivity...

  2. Precursor polymer approach towards functional conjugated polymer networks and ultrathin film electro-optical applications

    Science.gov (United States)

    Taranekar, Prasad

    Conjugated polymers are organic semiconductors which are of interest to a wide variety of optical, electronic, opto-electronic, and sensory applications; including light emitting diodes, thin film transistors, photovoltaic cells, and chemical sensors. While conducting polymers have some similarities to conventional polymeric materials, it is clearly the extensive main chain pi-conjugated structure and its implicit electro-optical properties that make it distinct. The same structure, however, gives it "chain stiffness" that affects its physical behavior. As a direct consequence of this, virtually all unsubstituted conducting polymers are found to be intractable and insoluble. This dissertation details the issue of tailoring the electro-optical properties and processability of conjugated polymers via a novel "precursor polymer approach". In this approach, electroactive side group units of either similar or different kind are tethered to a polymeric backbone. This combination determines the eventual electro-optical and electrochemical properties of these polymers including their ability to form ultrathin films. Thus, the desired macroscopic property is transformed by designing new precursor polymer structures, manipulating polymer-based compositions and blends, and the exploration and exploitation of their electrochemical processing conditions. In Chapters 2, 3, and 4, we have used single or binary electroactive compositions of species such as pyrrole, thiophene, carbazole and terthiophene are tethered to a linear polymeric backbone. Besides, the linear approach, in Chapters 5 and 6, we have also explored the use of generational dendrimers as backbone with carbazole units attached as peripheral electroactive groups. These precursor polymers were then subjected to electrochemical cross-linking to generate high optical quality ultrathin films on a conducting substrate such as indium tin oxide (ITO) or Au surfaces. The reaction of such electroactive species inimically

  3. Morphology in electrochemically grown conducting polymer films

    Science.gov (United States)

    Rubinstein, Israel; Gottesfeld, Shimshon; Sabatani, Eyal

    1992-01-01

    A conducting polymer film with an improved space filling is formed on a metal electrode surface. A self-assembling monolayer is formed directly on the metal surface where the monolayer has a first functional group that binds to the metal surface and a second chemical group that forms a chemical bonding site for molecules forming the conducting polymer. The conducting polymer is then conventioonally deposited by electrochemical deposition. In one example, a conducting film of polyaniline is formed on a gold electrode surface with an intermediate monolayer of p-aminothiophenol.

  4. Exploring the relationship between nanoscale dynamics and macroscopic rheology in natural polymer gums.

    Science.gov (United States)

    Grein-Iankovski, Aline; Riegel-Vidotti, Izabel C; Simas-Tosin, Fernanda F; Narayanan, Suresh; Leheny, Robert L; Sandy, Alec R

    2016-11-23

    We report a study connecting the nanoscale and macroscale structure and dynamics of Acacia mearnsii gum as probed by small-angle X-ray scattering (SAXS), X-ray photon correlation spectroscopy (XPCS) and rheology. Acacia gum, in general, is a complex polysaccharide used extensively in industry. Over the analyzed concentration range (15 to 30 wt%) the A. mearnsii gum is found to have a gel-like linear rheology and to exhibit shear thinning flow behavior under steady shear. The gum solutions exhibited a steadily increasing elastic modulus with increasing time after they were prepared and also the emergence of shear thickening events within the shear thinning behavior, characteristic of associative polymers. XPCS measurements using gold nanoparticles as tracers were used to explore the microscopic dynamics within the biopolymer gels and revealed a two-step relaxation process with a partial decay at inaccessibly short times, suggesting caged motion of the nanoparticles, followed by a slow decay at later delay times. Non-diffusive motion evidenced by a compressed exponential line shape and an inverse relationship between relaxation time and wave vector characterizes the slow dynamics of A. mearnsii gum gels. Surprisingly, we have determined that the nanometer-scale mean square displacement of the nanoparticles showed a close relationship to the values predicted from the macroscopic elastic properties of the material, obtained through the rheology experiments. Our results demonstrate the potential applicability of the XPCS technique in the natural polymers field to connect their macroscale properties with their nanoscale structure and dynamics.

  5. Optical properties of thin polymer films

    Science.gov (United States)

    Kasarova, Stefka N.; Sultanova, Nina G.; Petrova, Tzveta; Dragostinova, Violeta; Nikolov, Ivan

    2009-10-01

    In this report three types of optical polymer thin films deposited on glass substrates are investigated. Transmission spectra of the polymer samples are obtained in the range from 400 nm to 1500 nm. A laser microrefractometer has been used to measure the refractive indices of the examined materials at 406, 656, 910 and 1320 nm. Dispersion properties of the polymer films are analyzed on the base of the Cauchy-Schott's and Sellmeier`s approximations. Dispersion coefficients are calculated and dispersion charts in the visible and near infrared spectral regions are presented and compared. Abbe numbers of mean and partial dispersion of the polymer films are obtained. Calculation of refractive indices at many laser emission wavelengths in the considered spectral range is accomplished.

  6. In situ observation of macroscopic phase separation in cobalt hexacyanoferrate film

    Science.gov (United States)

    Takachi, Masamitsu; Moritomo, Yutaka

    2017-02-01

    Lithium-ion secondary batteries (LIBs) store electric energy via Li+ deintercalation from cathode materials. The Li+ deintercalation frequently drives a first-order phase transition of the cathode material as a result of the Li-ordering or Li-concentration effect and causes a phase separation (PS) into the Li-rich and Li-poor phases. Here, we performed an in situ microscopic investigation of the PS dynamics in thin films of cobalt hexacyanoferrate, LixCo[Fe(CN)6]0.9, against Li+ deintercalation. The thick film (d = 1.5 μm) shows a characteristic macroscopic PS of several tens of μm into the green (Li1.6Co[Fe(CN)6]0.9) and black (Li.6Co[Fe(CN)6]0.9) phases in the x range of 1.0 < x < 1.6. Reflecting the substrate strain, the thin film (d = 0.5 μm) shows no trace of the PS in the entire x region. Our observation suggests that the macroscopic PS plays a significant role in the charge/discharge dynamics of the cathode.

  7. Thin liquid films dewetting and polymer flow

    CERN Document Server

    Blossey, Ralf

    2012-01-01

    This book is a treatise on the thermodynamic and dynamic properties of thin liquid films at solid surfaces and, in particular, their rupture instabilities. For the quantitative study of these phenomena, polymer thin films haven proven to be an invaluable experimental model system.   What is it that makes thin film instabilities special and interesting, warranting a whole book? There are several answers to this. Firstly, thin polymeric films have an important range of applications, and with the increase in the number of technologies available to produce and to study them, this range is likely to expand. An understanding of their instabilities is therefore of practical relevance for the design of such films.   Secondly, thin liquid films are an interdisciplinary research topic. Interdisciplinary research is surely not an end to itself, but in this case it leads to a fairly heterogeneous community of theoretical and experimental physicists, engineers, physical chemists, mathematicians and others working on the...

  8. Antimicrobial polymer films for food packaging

    Science.gov (United States)

    Concilio, S.; Piotto, S.; Sessa, L.; Iannelli, P.; Porta, A.; Calabrese, E. C.; Galdi, M. R.; Incarnato, L.

    2012-07-01

    New antimicrobial polymeric systems were realized introducing new antimicrobial azo compounds in PP and LDPE matrices. The polymeric materials containing different percentage of azo compounds were mold-casted and the obtained film were tested in vitro against Gram+ and Gram- bacteria and fungi. These results hold promise for the fabrication of bacteria-resistant polymer films by means of simple melt processing with antimicrobial azo-dyes.

  9. Bending and Fracture in Thin Polymer Films during Capillary Origami Assembly

    Science.gov (United States)

    Twohig, Timothy; Croll, Andrew

    Capillary origami uses liquid tension to bend thin films into useful shapes and structures. The ability to scale this process to the microscopic range has led to growing interest in capillary origami and many potential applications. Clearly, the creation of three dimensional structures from flat sheets depends deeply on a combination of properties: fluid tensions, film thickness, film modulus and importantly the film's fracture properties. Fractures in a film are a critical component of macroscopic origami but macroscopic methods for creating these fractures are not possible at the microscopic scale. We present an experimental investigation of the interplay of capillary forces and material properties in the creation of controlled fractures in thin polymer films. Specifically, we use capillary forces to lift and bend a thin polymer film to the point of fracture using a variety of film thicknesses and material properties and attempt to model the basic underlying physics. We observe the creation of delaminations and fractures at pre-determined sites that can be tailored to specific shapes to be utilized in capillary origami.

  10. Quantifying residual stress in nanoscale thin polymer films via surface wrinkling.

    Science.gov (United States)

    Chung, Jun Young; Chastek, Thomas Q; Fasolka, Michael J; Ro, Hyun Wook; Stafford, Christopher M

    2009-04-28

    Residual stress, a pervasive consequence of solid materials processing, is stress that remains in a material after external forces have been removed. In polymeric materials, residual stress results from processes, such as film formation, that force and then trap polymer chains into nonequilibrium stressed conformations. In solvent-cast films, which are central to a wide range of technologies, residual stress can cause detrimental effects, including microscopic defect formation and macroscopic dimensional changes. Since residual stress is difficult to measure accurately, particularly in nanoscale thin polymer films, it remains a challenge to understand and control. We present here a quantitative method of assessing residual stress in polymer thin films by monitoring the onset of strain-induced wrinkling instabilities. Using this approach, we show that thin (>100 nm) polystyrene films prepared via spin-coating possess residual stresses of approximately 30 MPa, close to the crazing and yield stress. In contrast to conventional stress measurement techniques such as wafer curvature, our technique has the resolution to measure residual stress in films as thin as 25 nm. Furthermore, we measure the dissipation of residual stress through two relaxation mechanisms: thermal annealing and plasticizer addition. In quantifying the amount of residual stress in these films, we find that the residual stress gradually decreases with increasing annealing time and plasticizer amounts. Our robust and simple route to measure residual stress adds a key component to the understanding of polymer thin film behavior and will enable identification of more effective processing routes that mitigate the detrimental effects of residual stress.

  11. Thin films of photoactive polymer blends.

    Science.gov (United States)

    Ruderer, Matthias A; Metwalli, Ezzeldin; Wang, Weinan; Kaune, Gunar; Roth, Stephan V; Müller-Buschbaum, Peter

    2009-03-09

    The morphology inside photoactive blended films of two conjugated homopolymers poly [(1-methoxy)-4-(2-ethylhexyloxy)-p-phenylene-vinylene] (MEH-PPV) and poly(3-hexylthiophene-2,5-diyl) (P3HT) is investigated. For both homopolymers a linear dependence of the installed film thickness from the concentration of the polymer solution used in spin coating is probed. This dependence allows preparation of an efficient series of blended films with constant thickness and different blending ratios. Information about the lateral structure inside the films is gained from grazing incidence small angle X-ray scattering. At the calculated critical blending ratio the smallest lateral separation between adjacent domains is found representing the highest surface contact between both homopolymers in the films. The presence of wetting layers at both interfaces as detected with X-ray reflectivity and atomic force microscopy is promising for photovoltaic applications. UV/Vis spectroscopy complements the structural investigation.

  12. Photothermoelectric p-n junction photodetector with intrinsic broadband polarimetry based on macroscopic carbon nanotube films.

    Science.gov (United States)

    He, Xiaowei; Wang, Xuan; Nanot, Sébastien; Cong, Kankan; Jiang, Qijia; Kane, Alexander A; Goldsmith, John E M; Hauge, Robert H; Léonard, François; Kono, Junichiro

    2013-08-27

    Light polarization is used in the animal kingdom for communication, navigation, and enhanced scene interpretation and also plays an important role in astronomy, remote sensing, and military applications. To date, there have been few photodetector materials demonstrated to have direct polarization sensitivity, as is usually the case in nature. Here, we report the realization of a carbon-based broadband photodetector, where the polarimetry is intrinsic to the active photodetector material. The detector is based on p-n junctions formed between two macroscopic films of single-wall carbon nanotubes. A responsivity up to ~1 V/W was observed in these devices, with a broadband spectral response spanning the visible to the mid-infrared. This responsivity is about 35 times larger than previous devices without p-n junctions. A combination of experiment and theory is used to demonstrate the photothermoelectric origin of the responsivity and to discuss the performance attributes of such devices.

  13. Soft matter beats hard matter: rupturing of thin metallic films induced by mass transport in photosensitive polymer films.

    Science.gov (United States)

    Yadavalli, Nataraja Sekhar; Linde, Felix; Kopyshev, Alexey; Santer, Svetlana

    2013-08-28

    The interface between thin films of metal and polymer materials play a significant role in modern flexible microelectronics viz., metal contacts on polymer substrates, printed electronics and prosthetic devices. The major emphasis in metal-polymer interface is on studying how the externally applied stress in the polymer substrate leads to the deformation and cracks in metal film and vice versa. Usually, the deformation process involves strains varying over large lateral dimensions because of excessive stress at local imperfections. Here we show that the seemingly random phenomena at macroscopic scales can be rendered rather controllable at submicrometer length scales. Recently, we have created a metal-polymer interface system with strains varying over periods of several hundred nanometers. This was achieved by exploiting the formation of surface relief grating (SRG) within the azobenzene containing photosensitive polymer film upon irradiation with light interference pattern. Up to a thickness of 60 nm, the adsorbed metal film adapts neatly to the forming relief, until it ultimately ruptures into an array of stripes by formation of highly regular and uniform cracks along the maxima and minima of the polymer topography. This surprising phenomenon has far-reaching implications. This is the first time a direct probe is available to estimate the forces emerging in SRG formation in glassy polymers. Furthermore, crack formation in thin metal films can be studied literally in slow motion, which could lead to substantial improvements in the design process of flexible electronics. Finally, cracks are produced uniformly and at high density, contrary to common sense. This could offer new strategies for precise nanofabrication procedures mechanical in character.

  14. Porous Polyolefin Films via Polymer Blends

    Science.gov (United States)

    Macosko, Chris

    Porous polymer films have broad application including battery separators, membrane supports and filters. Polyolefins are attractive for these applications because of their solvent resistance, low electrical and thermal conductivity, easy fabrication and cost. We will describe fabrication of porous films using cocontinuous blends of a polyolefin with another polymer which can be readily removed with a solvent. Methods to image and control the cocontinuous morphology will be presented.Bell, J. R., K. Chang, C. R. Lopez-Barron, C. W. Macosko, and D. C. Morse, ''Annealing of cocontinuous polymer blends: effect of block copolymer molecular weight and architecture,'' Macromolecules 43, 5024-5032 (2010).Lopez-Barron, C. R., and C. W. Macosko, ''Direct measurement of interface anisotropy of bicontinuous structures via 3D image analysis,'' Langmuir 26, 14284-14293 (2010).Trifkovic, M., A. T. Hedegaard, K. Huston, M. Sheikhzadeh, and C. W. Macosko, ''Porous films via PE/PEO cocontinuous blends,'' Macromolecules 45, 6036-6044 (2012).Hedegaard, A.T., L.L. Gu and C. W. Macosko, ``Effect of Extensional Viscosity on Cocontinuity of Immiscible Polymer Blends'' J. Rheol. 59, 1397-1417 (2015).

  15. High-Temperature Capacitor Polymer Films

    Science.gov (United States)

    Tan, Daniel; Zhang, Lili; Chen, Qin; Irwin, Patricia

    2014-12-01

    Film capacitor technology has been under development for over half a century to meet various applications such as direct-current link capacitors for transportation, converters/inverters for power electronics, controls for deep well drilling of oil and gas, direct energy weapons for military use, and high-frequency coupling circuitry. The biaxially oriented polypropylene film capacitor remains the state-of-the-art technology; however, it is not able to meet increasing demand for high-temperature (>125°C) applications. A number of dielectric materials capable of operating at high temperatures (>140°C) have attracted investigation, and their modifications are being pursued to achieve higher volumetric efficiency as well. This paper highlights the status of polymer dielectric film development and its feasibility for capacitor applications. High-temperature polymers such as polyetherimide (PEI), polyimide, and polyetheretherketone were the focus of our studies. PEI film was found to be the preferred choice for high-temperature film capacitor development due to its thermal stability, dielectric properties, and scalability.

  16. Effects of ion beam treatment on atomic and macroscopic adhesion of copper to different polymer materials

    Science.gov (United States)

    Zaporojtchenko, V.; Zekonyte, J.; Faupel, F.

    2007-12-01

    Low-energy ion irradiation of polymer induces different phenomena in the near surface layer, which effect strongly the metal-polymer interface formation and promotes adhesion of polymers to metals. Low-energy argon and oxygen ion beams were used to alter the chemical and physical properties of different polymers (PS (polystyrene), PαMS (poly(α-methylstyrene), BPA-PC (bisphenol-A-polycarbonate) and PMMA (poly(methyl methacrylate)), in order to understand the adhesion phenomena between a deposited Cu layer and the polymers. The resulting changes were investigated by various techniques including X-ray photoelectron spectroscopy, measurements of the metal condensation coefficient and a new technique to measure cross-linking at the polymer surface. Two types of practical adhesion strengths of Cu-polymer systems, measured using 90° peel tests, were observed: (i) peel strength increased at low ion fluences, reached a maximum and then decreased after prolonged treatment and (ii) no improvement in the peel strength on treated polymer surfaces was recorded. The improvement in the metal-polymer adhesion in the ion fluence range of 10 13-10 15 cm -2 is attributed to the creation of a large density of new adsorption sites resulting in a larger contact area and incorporation of chemically active groups that lead to increased interaction between metal and polymer by metal-oxygen-polymer species formation. XPS analysis of peeled-off surfaces showed that in most cases the failure location changed from interfacial for untreated polymers to cohesive failure in the polymer for treated surfaces. These observations and measurements of the metal condensation coefficients suggest that bonding is improved at the metal-polymer interface for all metal-polymer systems. However, the decrease in the peel strength at high ion fluences is attributed to the formation of a weak boundary layer in polymers. The correlation between sputter rate of polymers and altering in the peel strength for

  17. Macroscopically aligned molecular stacking structures in mesogenic phthalocyanine derivative films fabricated by heated spin-coating method

    Energy Technology Data Exchange (ETDEWEB)

    Higashi, Takuya; Fiderana Ramananarivo, Mihary; Ohmori, Masashi; Yoshida, Hiroyuki; Fujii, Akihiko, E-mail: afujii@opal.eei.eng.osaka-u.ac.jp; Ozaki, Masanori

    2015-11-02

    Spin-coated films of a mesogenic phthalocyanine derivative, 1,4,8,11,15,18,22,25-octahexylphthalocyanine (C6PcH{sub 2}), with macroscopic alignment of molecular stacking structure were obtained by processing in liquid-crystal phase of C6PcH{sub 2}. The column axis direction of the hexagonal columnar structure of C6PcH{sub 2} was determined by microscopic observation and polarized optical absorption measurement and was uniform in the millimeter-scale area. Highly ordered molecular stacking structure in the film, which is similar to the single crystal, was clarified by measurement of molecular tilting angle with respect to the column axis. The origin of the macroscopic molecular alignment during film formation was investigated by taking the process-temperature-dependent properties of the films into consideration. - Highlights: • We fabricated mesogenic phthalocyanine films by heated spin-coating method. • The maximum domain size was obtained by fabricating at mesogenic-phase temperature. • The optic axis direction in the film was uniform in the millimeter-scale area. • The crystalline structure in the film was similar to that of the single crystal. • The effects of mesogenic phase during the formation on the molecular alignment were presumed.

  18. Dynamic control of crystallinity in polymer film casting process

    OpenAIRE

    Thananchai Leephakpreeda

    2005-01-01

    This paper presents an approach for dynamic control of crystallinity in polymer film casting process. As known, the transients of crystallization dictate the microstructures of semi-crystalline polymer during solidification. In turn, the properties of finished products can be determined by adjustable variables in polymer film casting process such as temperature of chill roll. In this work, an experimental model of the solidification in film casting process is derived by a system identificatio...

  19. Efficiency Improvement of Heterojunction Polymer Photovoltaic Cells through Controlling the Morphology of the Polymer Film

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    1 Results Polymer photovoltaic cells, which provide clean and renewable energy sources, have gained more and more attention. Polymer photovoltaic cells have the advantage of low fabrication cost and high mechanical flexibility. Polymers can be processed through a solution process, so that a homogeneous polymer film could be readily prepared in a large area. Recently, the light-to-electricity conversion efficiency of the polymer photovoltaic cells was improved significantly[1-2]. Polymer donor and organi...

  20. Multiple High Voltage Pulse Stressing of Polymer Thick Film Resistors

    Directory of Open Access Journals (Sweden)

    Busi Rambabu

    2014-01-01

    Full Text Available The purpose of this paper is to study high voltage interactions in polymer thick film resistors, namely, polyvinyl chloride- (PVC- graphite thick film resistors, and their applications in universal trimming of these resistors. High voltages in the form of impulses for various pulse durations and with different amplitudes have been applied to polymer thick film resistors and we observed the variation of resistance of these resistors with high voltages. It has been found that the resistance of polymer thick film resistors decreases in the case of higher resistivity materials and the resistance of polymer thick film resistor increases in the case of lower resistivity materials when high voltage impulses are applied to them. It has been also found that multiple high voltage pulse (MHVP stressing can be used to trim the polymer thick film resistors either upwards or downwards.

  1. On cavitation and macroscopic behaviour of amorphous polymer-rubber blends

    Directory of Open Access Journals (Sweden)

    Naima Belayachi et al

    2008-01-01

    Full Text Available The macroscopic behaviour of rubber-modified polymethyl methacrylate (PMMA was investigated by taking into account the microdeformation mechanisms of rubber cavitation. The dependence of the macroscopic stress–strain behaviour of matrix deformation on the cavitation of rubber particles was discussed. A phenomenological elastic-viscoplastic model was used to model the behaviour of the matrix material, while the rubber particles were modelled with the hyperelasticity theory. A two-phase composite material with a periodic arrangement of reinforcing particles of a circular unit cell section was considered. Finite-element analysis was used to determine the local stresses and strains in the two-phase composite. In order to describe the cavitation of the rubber particles, a criterion of void nucleation is implemented in the finite-element (FE code. A comparison of the numerically predicted response with experimental result indicates that the numerical homogenisation analysis gives satisfactory prediction results.

  2. Thermophoresis of dissolved molecules and polymers: Consideration of the temperature-induced macroscopic pressure gradient.

    Science.gov (United States)

    Semenov, Semen; Schimpf, Martin

    2004-01-01

    The movement of molecules and homopolymer chains dissolved in a nonelectrolyte solvent in response to a temperature gradient is considered a consequence of temperature-induced pressure gradients in the solvent layer surrounding the solute molecules. Local pressure gradients are produced by nonuniform London-van der Waals interactions, established by gradients in the concentration (density) of solvent molecules. The density gradient is produced by variations in solvent thermal expansion within the nonuniform temperature field. The resulting expression for the velocity of the solute contains the Hamaker constants for solute-solvent and solute-solute interactions, the radius of the solute molecule, and the viscosity and cubic coefficient of thermal expansion of the solvent. In this paper we consider an additional force that arises from directional asymmetry in the interaction between solvent molecules. In a closed cell, the resulting macroscopic pressure gradient gives rise to a volume force that affects the motion of dissolved solutes. An expression for this macroscopic pressure gradient is derived and the resulting force is incorporated into the expression for the solute velocity. The expression is used to calculate thermodiffusion coefficients for polystyrene in several organic solvents. When these values are compared to those measured in the laboratory, the consistency is better than that found in previous reports, which did not consider the macroscopic pressure gradient that arises in a closed thermodiffusion cell. The model also allows for the movement of solute in either direction, depending on the relative values of the solvent and solute Hamaker constants.

  3. Macroscopic and high-throughput printing of aligned nanostructured polymer semiconductors for MHz large-area electronics

    Science.gov (United States)

    Bucella, Sadir G.; Luzio, Alessandro; Gann, Eliot; Thomsen, Lars; McNeill, Christopher R.; Pace, Giuseppina; Perinot, Andrea; Chen, Zhihua; Facchetti, Antonio; Caironi, Mario

    2015-09-01

    High-mobility semiconducting polymers offer the opportunity to develop flexible and large-area electronics for several applications, including wearable, portable and distributed sensors, monitoring and actuating devices. An enabler of this technology is a scalable printing process achieving uniform electrical performances over large area. As opposed to the deposition of highly crystalline films, orientational alignment of polymer chains, albeit commonly achieved by non-scalable/slow bulk alignment schemes, is a more robust approach towards large-area electronics. By combining pre-aggregating solvents for formulating the semiconductor and by adopting a room temperature wired bar-coating technique, here we demonstrate the fast deposition of submonolayers and nanostructured films of a model electron-transporting polymer. Our approach enables directional self-assembling of polymer chains exhibiting large transport anisotropy and a mobility up to 6.4 cm2 V-1 s-1, allowing very simple device architectures to operate at 3.3 MHz. Thus, the proposed deposition strategy is exceptionally promising for mass manufacturing of high-performance polymer circuits.

  4. Polymer compositions, polymer films and methods and precursors for forming same

    Science.gov (United States)

    Klaehn, John R; Peterson, Eric S; Orme, Christopher J

    2013-09-24

    Stable, high performance polymer compositions including polybenzimidazole (PBI) and a melamine-formaldehyde polymer, such as methylated, poly(melamine-co-formaldehyde), for forming structures such as films, fibers and bulky structures. The polymer compositions may be formed by combining polybenzimidazole with the melamine-formaldehyde polymer to form a precursor. The polybenzimidazole may be reacted and/or intertwined with the melamine-formaldehyde polymer to form the polymer composition. For example, a stable, free-standing film having a thickness of, for example, between about 5 .mu.m and about 30 .mu.m may be formed from the polymer composition. Such films may be used as gas separation membranes and may be submerged into water for extended periods without crazing and cracking. The polymer composition may also be used as a coating on substrates, such as metal and ceramics, or may be used for spinning fibers. Precursors for forming such polymer compositions are also disclosed.

  5. Resonant infrared pulsed laser deposition of thin biodegradable polymer films

    DEFF Research Database (Denmark)

    Bubb, D.M.; Toftmann, B.; Haglund Jr., R.F.

    2002-01-01

    Thin films of the biodegradable polymer poly(DL-lactide-co-glycolide) (PLGA) were deposited using resonant infrared pulsed laser deposition (RIR-PLD). The output of a free-electron laser was focused onto a solid target of the polymer, and the films were deposited using 2.90 (resonant with O-H str...

  6. Relaxation of non-equilibrium entanglement networks in thin polymer films

    Science.gov (United States)

    Fowler, Paul; McGraw, Joshua; Ferrari, Melissa; Dalnoki-Veress, Kari

    2013-03-01

    It is well established that polymer films, prepared by spincoating, inherit non-equilibrium chain conformations which can affect macroscopic film properties. Here we present the results of crazing measurements that elucidate the non-equilibirum chain configurations in spin-cast films. Furthermore, we find that the entanglement network equilibrates on a time scale comparable to one reptation time. In a second set of experiments, we confine polymers to films with thickness comparable to the molecular size. By stacking two such films at room temperature, a glassy bilayer film with a buried entropic interface is created. According to Silberberg's reflection principle, such an interface has an entropic cost associated with the restricted configurations of molecules that cannot cross the mid-plane of the bilayer. In the melt, the interface heals as chains from the two layers mix and entangle with one another. Crazing measurements reveal that it takes less than one bulk reptation time for a bilayer to become indistinguishable from a single film.

  7. Dynamic control of crystallinity in polymer film casting process

    Directory of Open Access Journals (Sweden)

    Thananchai Leephakpreeda

    2005-05-01

    Full Text Available This paper presents an approach for dynamic control of crystallinity in polymer film casting process. As known, the transients of crystallization dictate the microstructures of semi-crystalline polymer during solidification. In turn, the properties of finished products can be determined by adjustable variables in polymer film casting process such as temperature of chill roll. In this work, an experimental model of the solidification in film casting process is derived by a system identification technique. This model is used to design a digital feedback controller including a state estimator. The simulation results show the effectiveness of the proposed control technique on an extruded film.

  8. Measuring the gain dynamics in a conjugated polymer film

    CERN Document Server

    Van den Berg, S A; Hooft, G W; Eliel, E R

    2004-01-01

    We present a simple method for measuring the gain decay time in a conjugated polymer film by optically exciting the film with two mutually delayed ultrashort pump pulses. When the pump is set at such a power level that amplified spontaneous emission marginally develops along the polymer waveguide, the total output emitted from its edge decays exponentially as a function of the interpulse delay. The corresponding decay time represents the decay time of the gain of the polymer material.

  9. Piezoelectric polymer and ceramic ultrafine fibers for piezocomposite films

    OpenAIRE

    Yördem, Sinan Onur; Yordem, Sinan Onur; Papila, Melih; Menceloğlu, Yusuf Z.; Menceloglu, Yusuf Z.; Öğüt, Erdem; Ogut, Erdem; Gülleroğlu, Mert; Gulleroglu, Mert

    2006-01-01

    This paper describes the process development and characterization of Poly(vinylidene fluoride) (PVDF) films and fiber mats and Zinc Oxide (ZnO) fibers as ingredients of a future piezo-composite film. The polymer system PVDF is electroactive and processed here by solution casting and annealing to form active films. Electrospinning of PVDF and Poly(vinyl alcohol)-Zincacetate precursor solutions were also under investigation to produce randomly oriented polymer and ceramic fiber mats, respective...

  10. Phase Equilibria in Thin Polymer Films

    Science.gov (United States)

    Müller, M.; Binder, K.; Albano, E. V.

    Within self-consistent field theory and Monte Carlo simulations the phase behavior of a symmetrical binary AB polymer blend confined into a thin film is studied. The film surfaces interact with the monomers via short ranged potentials. One surface attracts the A component and the corresponding semi-infinite system exhibits a first order wetting transition. The surface interaction of the opposite surface is varied as to study the crossover from capillary condensation for symmetric surface fields to interface localization/delocalization transition for antisymmetric surface fields. In the former case the phase diagram has a single critical point close to the bulk critical point. In the latter case the phase diagram exhibits two critical points which correspond to the prewetting critical points of the semi-infinite system. Only below a triple point there is a single two-phase coexistence region. The crossover between these qualitatively different limiting behaviors occurs gradually, however, the critical temperature and the critical composition exhibit a non-monotonic dependence on the surface field. The dependence of the phase behavior for antisymmetric boundaries is studied as a function of the film thickness and the strength of the surface interactions. Upon reducing the film thickness or decreasing the strength of the surface interactions we can change the order of the interface localization/delocalization transition from first to second. The role of fluctuations is explored via Monte Carlo simulations of a coarse grained lattice model. Close to the (prewetting) critical points we observe 2D Ising critical behavior. Also, there is a rich crossover behavior between Ising critical, tricritical and mean field behavior. At lower temperatures capillary waves of the AB interface lead to a pronounced dependence of the effective interface potential on the lateral system size.

  11. Thermochemical study of amino acid imprinted polymer films.

    Science.gov (United States)

    Chai, Ziyi; BelBruno, Joseph J

    2015-11-01

    Molecularly imprinted polymers provide an alternative to traditional methods of amino acid analysis. The imprinted polymers are more robust and significantly less expensive than, for example, ELISA analysis. Amino acid imprinted nylon-6 thin films were studied by differential scanning calorimetry and scanning electron microscopy. Endothermic peaks were observed for imprinted films at temperatures higher than that for pure nylon, indicating the formation of a more-ordered, hydrogen bonded polymer. Removal of the amino acid from the imprinted film resulted in reversion to the peak observed for pure nylon-6. Additives, β-cyclodextrin and multiwalled carbon nanotubes, were added to the imprinted polymer solutions as a means to increase the porosity of the films. These studies resulted in alternative morphologies and calorimetric results that provide additional functionalities and applications for imprinted polymers.

  12. Molecular dynamics simulation of the viscocapillary leveling of polymer films

    CERN Document Server

    Tanis, Ioannis; Salez, Thomas; Raphaël, Elie; Maggs, Anthony C; Baschnagel, Jörg

    2016-01-01

    Surface tension-driven flow techniques have recently emerged as an efficient means of shedding light into the rheology of thin polymer films. Motivated by experimental and theoretical approaches in films bearing a varying surface topography, we present results on the viscocapillary relaxation of a square pattern at the free surface of a polymer film, using molecular dynamics simulations of a coarse-grained polymer model. Height profiles are monitored as a function of time after heating the system above its glass-transition temperature. The associated relaxation rates are in agreement with the low-Reynolds-number hydrodynamic model, thus confirming the utility of the simulation method.

  13. Photopatterning of heterostructured polymer Langmuir-Blodgett films

    Energy Technology Data Exchange (ETDEWEB)

    Li Tiesheng [Department of Chemistry, Key Lab of Biological Chemistry and Organic Chemistry of Henan Province, Zhengzhou University, Daxue road 75, Zhengzhou 450052 (China); Key Lab of Advanced Information Nano-materials of Zhengzhou, Daxue road 75, Zhengzhou 450052 (China)], E-mail: lts34@zzu.edu.cn; Mitsuishi, Masaya [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Aobaku, 2-1-1, Katahira, Sendai (Japan); Miyashita, Tokuji [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, Aobaku, 2-1-1, Katahira, Sendai (Japan)], E-mail: miya@tagen.tohoku.ac.jp

    2008-02-29

    Heterostructured polymer Langmuir-Blodgett (LB) film prepared by using poly(N-dodecylacrylamide-co-t-butyl 4-vinylphenyl carbonate) (p(DDA-tBVPC53)) and poly(N-neopentyl methacrylamide-co-9-anthrylmethyl methacrylate) (p(nPMA-AMMA10)) polymer LB films which can act as photogenerator layers were investigated. Patterns with a resolution of 0.75 {mu}m were obtained on heterostructured polymer LB films composed of 4 layers of p(nPMA-AMMA10) LB film (top layers) and 40 layers of p(DDA-tBVPC53) LB film (under layers) on a silicon wafer by deep UV irradiation followed by development with 1% tetramethylammonium hydroxide aqueous solution. The sensitivity of the heterostructured polymer LB films was improved without loss of the resolution compared with p(DDA-tBVPC53) LB film. The etch resistance of the heterostructured polymer LB films was sufficiently good to allow patterning of a copper film suitable for photomask fabrication.

  14. Electrochemical Formation of Polypyrrole-carboxymethylcellulose Conducting Polymer Composite Films

    Institute of Scientific and Technical Information of China (English)

    H.N.M. Ekramul Mahmud; Anuar Kassim; Zulkarnain Zainal; Wan Mahmood Mat Yunus

    2005-01-01

    The electrochemical preparation of polypyrrole-carboxymethylcellulose (PPY-CMC) conducting polymer composite films on indium tin oxide (ITO) glass electrode from an aqueous solution containing pyrrole monomer, ptoluenesulfonate electrolyte and carboxymethylcellulose insulating polymer is reported. The characterization by Fourier transform infrared spectroscopy (FT-IR) shows that carboxymethylcellulose (CMC) has been successfully incorporated into polypyrrole structure forming PPY-CMC polymer composite films. The conductivity of the prepared composite films was found to increase with increaseing CMC concentration in pyrrole solution. The optical microscopic results show the influence of CMC concentration in the pyrrole solution over the morphological changes of the prepared films. The dynamic mechanical analysis (DMA) on the prepared PPY-CMC film reveals the higher plastic property of the PPY-CMC composite film.

  15. Characterization of polymer thin films obtained by pulsed laser deposition

    Science.gov (United States)

    Palla-Papavlu, A.; Dinca, V.; Ion, V.; Moldovan, A.; Mitu, B.; Luculescu, C.; Dinescu, M.

    2011-04-01

    The development of laser techniques for the deposition of polymer and biomaterial thin films on solid surfaces in a controlled manner has attracted great attention during the last few years. Here we report the deposition of thin polymer films, namely Polyepichlorhydrin by pulsed laser deposition. Polyepichlorhydrin polymer was deposited on flat substrate (i.e. silicon) using an NdYAG laser (266 nm, 5 ns pulse duration and 10 Hz repetition rate). The obtained thin films have been characterized by atomic force microscopy, scanning electron microscopy, Fourier transform infrared spectroscopy and spectroscopic ellipsometry. It was found that for laser fluences up to 1.5 J/cm 2 the chemical structure of the deposited polyepichlorhydrin polymer thin layers resembles to the native polymer, whilst by increasing the laser fluence above 1.5 J/cm 2 the polyepichlorohydrin films present deviations from the bulk polymer. Morphological investigations (atomic force microscopy and scanning electron microscopy) reveal continuous polyepichlorhydrin thin films for a relatively narrow range of fluences (1-1.5 J/cm 2). The wavelength dependence of the refractive index and extinction coefficient was determined by ellipsometry studies which lead to new insights about the material. The obtained results indicate that pulsed laser deposition method is potentially useful for the fabrication of polymer thin films to be used in applications including electronics, microsensor or bioengineering industries.

  16. Estimation of termostability of metal containing polymer films

    Directory of Open Access Journals (Sweden)

    Sh. Аmerkhanova

    2012-03-01

    Full Text Available The Derivatographic Analysis of metal containing polymer films based on polyvinyl alcohol was carried out, on these results the kinetic parameters of thermal destruction of the material was been calculated.

  17. Versatile solution for growing thin films of conducting polymers.

    Science.gov (United States)

    D'Arcy, Julio M; Tran, Henry D; Tung, Vincent C; Tucker-Schwartz, Alexander K; Wong, Rain P; Yang, Yang; Kaner, Richard B

    2010-11-16

    The method employed for depositing nanostructures of conducting polymers dictates potential uses in a variety of applications such as organic solar cells, light-emitting diodes, electrochromics, and sensors. A simple and scalable film fabrication technique that allows reproducible control of thickness, and morphological homogeneity at the nanoscale, is an attractive option for industrial applications. Here we demonstrate that under the proper conditions of volume, doping, and polymer concentration, films consisting of monolayers of conducting polymer nanofibers such as polyaniline, polythiophene, and poly(3-hexylthiophene) can be produced in a matter of seconds. A thermodynamically driven solution-based process leads to the growth of transparent thin films of interfacially adsorbed nanofibers. High quality transparent thin films are deposited at ambient conditions on virtually any substrate. This inexpensive process uses solutions that are recyclable and affords a new technique in the field of conducting polymers for coating large substrate areas.

  18. Investigation on CuO Dispersed PVA Polymer Films

    Directory of Open Access Journals (Sweden)

    R. Divya

    2015-05-01

    Full Text Available Addition of inorganic nanoparticles to polymers allows the modification of physical properties of polymers as well as the implementation of new features in polymer matrix. In the present work, we have made an attempt to disperse CuO nanoparticles in the polyvinyl alcohol (PVA and to understand the change in structural, optical and electrical properties of the polymer film. CuO nanoparticles were added in four different concentrations, viz. 2.5, 5.0, 7.5 and 10 wt%. A total of 5 films were prepared (including the pure PVA film, for comparison.The prepared films were subjected to XRD, FESEM, UV-Vis spectral, PL spectral and electrical analyses. The results obtained are reported.

  19. Engineering curvature in graphene ribbons using ultrathin polymer films.

    Science.gov (United States)

    Li, Chunyu; Koslowski, Marisol; Strachan, Alejandro

    2014-12-10

    We propose a method to induce curvature in graphene nanoribbons in a controlled manner using an ultrathin thermoset polymer in a bimaterial strip setup and test it via molecular dynamics (MD) simulations. Continuum mechanics shows that curvature develops to release the residual stress caused by the chemical and thermal shrinkage of the polymer during processing and that this curvature increases with decreasing film thickness; however, significant deformation is only achieved for ultrathin polymer films. Quite surprisingly, explicit MD simulations of the curing and annealing processes show that the predicted trend not just continues down to film thicknesses of 1-2 nm but that the curvature development is enhanced significantly in such ultrathin films due to surface tension effects. This combination of effects leads to very large curvatures of over 0.14 nm(-1) that can be tuned via film thickness. This provides a new avenue to engineer curvature and, thus, electromagnetic properties of graphene.

  20. In situ polarization of polymer films in microsensors

    Science.gov (United States)

    Kranz, M.; Allen, M. G.; Hudson, T.

    2012-04-01

    Electret and polymer piezoelectric films have been previously integrated into Micro Electro Mechanical System (MEMS) acoustic sensors and energy harvesters. Common techniques employed in MEMS polymer integration include corona discharge [1] and backlighted thyratron [2], followed by macro-scale assembly of the polymer into the micro device. In contrast, this paper reports a method for post-fabrication in-situ polarization of polymer films embedded within the MEMS device itself. The method utilizes microplasma discharges with self-aligned charging grids integrated within the device to charge fluoropolymer films in a fashion similar to the common corona discharge technique. This in-situ approach enables the integration of uncharged polymer films into MEMS and subsequent post-fabrication and post-packaging polarization, simultaneously enabling the formation of buried or encapsulated electrets as well as eliminating the need to restrict fabrication and packaging processes that might otherwise discharge pre-charged materials. Using the in situ approach, a microscale charging grid structure is fabricated and suspended a short distance above the polymer film. After fabrication of the charging grid, standard microfabrication steps are performed to build MEMS sensors. After completing the entire fabrication and packaging flow, the polarization process is performed. When energized by a high voltage, the sharp metal edges of the charging grid lead to high dielectric fields that ionize the air in the gap and force electric charge onto the polymer surface. This paper presents modeling and results for this in situ polarization process.

  1. Water-Induced Blister Formation in a Thin Film Polymer

    NARCIS (Netherlands)

    Berkelaar, R.P.; Bampoulis, Pantelis; Dietrich, E.; Jansen, H.P.; Zhang, Xuehua; Kooij, Ernst S.; Lohse, Detlef; Zandvliet, Henricus J.W.

    2015-01-01

    A failure mechanism of thin film polymers immersed in water is presented: the formation of blisters. The growth of blisters is counterintuitive as the substrates were noncorroding and the polymer does not swell in water. We identify osmosis as the driving force behind the blister formation. The

  2. Water induced blister formation in a thin film polymer

    NARCIS (Netherlands)

    Berkelaar, R.P.; Bampoulis, Pantelis; Dietrich, E.; Jansen, H.P.; Zhang, Xuehua; Kooij, Ernst S.; Lohse, Detlef; Zandvliet, Henricus J.W.

    2015-01-01

    A failure mechanism of thin film polymers immersed in water is presented: the formation of blisters. The growth of blisters is counterintuitive as the substrates were noncorroding and the polymer does not swell in water. We identify osmosis as the driving force behind the blister formation. The

  3. Water-Induced Blister Formation in a Thin Film Polymer

    NARCIS (Netherlands)

    Berkelaar, R.P.; Bampoulis, P.; Dietrich, E.; Jansen, H.P.; Zhang, X.; Kooij, E.S.; Lohse, D.; Zandvliet, Harold J.W.

    2015-01-01

    A failure mechanism of thin film polymers immersed in water is presented: the formation of blisters. The growth of blisters is counterintuitive as the substrates were noncorroding and the polymer does not swell in water. We identify osmosis as the driving force behind the blister formation. The dyna

  4. Water induced blister formation in a thin film polymer

    NARCIS (Netherlands)

    Berkelaar, R.P.; Bampoulis, P.; Dietrich, E.; Jansen, H.P.; Zhang, Xuehua; Kooij, E.S.; Lohse, D.; Zandvliet, H.J.W.

    2015-01-01

    A failure mechanism of thin film polymers immersed in water is presented: the formation of blisters. The growth of blisters is counterintuitive as the substrates were noncorroding and the polymer does not swell in water. We identify osmosis as the driving force behind the blister formation. The dyna

  5. “Electro-Click” on Conducting Polymer Films

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Lind, Johan Ulrik; Daugaard, Anders Egede

    for their own functionalization with high spatial resolution. Interdigitated microelectrodes prepared from the azide-containing conducting polymer were selectively functionalized in sequence by two alkyne-modified fluorophores by control of the applied potentials. “Electro-click” on conducting polymer films...

  6. Polymer Wall Formation Using Liquid-Crystal/Polymer Phase Separation Induced on Patterned Polyimide Films

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2004-12-01

    We could form lattice-shaped polymer walls in a liquid crystal (LC) layer through the thermal phase separation of an LC/polystyrene solution between substrates with polyimide films etched by short-wavelength ultraviolet irradiation using a photomask. The LC wetting difference between the polyimide and substrate surfaces caused the coalescence of growing LC droplets on patterned polyimide films with the progress of phase separation. Consequently, polymer walls were formed on substrate surface areas without polyimide films. The shape of the polymer wall formed became sharp with the use of rubbed polyimide films because the nucleation of growing LC droplets concentrated on the patterned polyimide films. It is thought that the increase in the alignment order of LC molecules in the solution near the rubbed polyimide films promotes the formation of LC molecular aggregation, which becomes the growth nuclei of LC droplets.

  7. Stress effects in prism coupling measurements of thin polymer films

    Science.gov (United States)

    Agan, S.; Ay, F.; Kocabas, A.; Aydinli, A.

    2005-02-01

    Due to the increasingly important role of some polymers in optical waveguide technologies, precise measurement of their optical properties has become important. Typically, prism coupling to slab waveguides made of materials of interest is used to measure the relevant optical parameters. However, such measurements are often complicated by the softness of the polymer films when stress is applied to the prism to couple light into the waveguides. In this work, we have investigated the optical properties of three different polymers, polystyrene (PS), polymethyl-methacrylate (PMMA), and benzocyclobutane (BCB). For the first time, the dependence of the refractive index, film thickness, and birefringence on applied stress in these thin polymer films was determined by means of the prism coupling technique. Both symmetric trapezoid shaped and right-angle prisms were used to couple the light into the waveguides. It was found that trapezoid shaped prism coupling gives better results in these thin polymer films. The refractive index of PMMA was found to be in the range of 1.4869 up to 1.4876 for both TE and TM polarizations under the applied force, which causes a small decrease in the film thickness of up to 0.06 μm. PMMA waveguide films were found not to be birefringent. In contrast, both BCB and PS films exhibit birefringence albeit of opposing signs.

  8. Fracture and fatigue of ultrathin nanoporous polymer films

    Science.gov (United States)

    Kearney, Andrew V.

    Nanoporous polymer layers are being considered for a range of emerging nanoscale applications, from low permittivity materials for interlayer dielectrics in microelectronics and anti-reflective coatings in optical technologies, to biosensors and size-selective membranes for biological applications. Polymer thin films have inherently low elastic modulus, strength and hardness, but exhibit fracture properties that are higher than those reported for glass, ceramic, and even some metal layers. However, constraint of a ductile polymer between two elastic layers is expected to affect the local plasticity ahead of a crack tip and its contribution to the film adhesion with films below a micron in thickness. Additionally, nanoporosity would be expected to have a deleterious effect on mechanical properties, producing materials and layers that are structurally weaker than fully dense versions they replace. Therefore, the integration of these nanoporous polymer layer at nanometer thicknesses would present significantly processing and mechanical reliability challenges. In this dissertation, surprising evidence is presented that nanoporous polymer films exhibit increasing fracture energy with increasing porosity. Such behavior is in stark contrast to a wide range of reported behavior for porous solids. A ductile nano-void growth and coalescence fracture mechanics-based model is presented to rationalize the increase in fracture toughness of the voided polymer film. The model is shown to explain the behavior in terms of a specific scaling of the size of the pores with pore volume fraction. It is demonstrated that the pore size must increase with close to a linear dependence on the volume fraction in order to increase rather than decrease the fracture energy. Independent characterization of the pore size as a function of volume fraction is shown to confirm predictions made by the model. The fracture behavior of these constrained polymer films are also examined with film thickness

  9. Pattern Formation and Quasicrystal Structure in Azobenzene Polymer Film

    Institute of Scientific and Technical Information of China (English)

    XU Ze-Da; CAI Zhi-Gang; ZHANG Ling-Zhi; LIU Yan-Fa; YANG Jie; SHE Wei-Long; ZHOU Jian-Ying

    2000-01-01

    Pattern formation in azobenzene polymer film by degenerate four-wave mixing is reported. Island arrays with specific patterns are analyzed with scanning electron microscopy and polarizing optical microscopy. It is demonstrated that the control of photo-induced nanostructure sized micropattern in the nonlinear organic film is possible by using properly polarized writing beams with the total incident power exceeding a certain threshold.

  10. Measurement Method of the Thickness Uniformity for Polymer Films

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Several methods for investigating the thickness uniformity of polymer thin films are presented as well as their measurement principles. A comparison of these experimental methods is given.The cylindrical lightwave reflection method is found to can obtain the thickness distribution along a certain direction.It is a simple and suitable method to evaluate the film thickness uniformity.

  11. A macroscopic model of proton transport through the membrane-ionomer interface of a polymer electrolyte membrane fuel cell

    Science.gov (United States)

    Kumar, Milan; Edwards, Brian J.; Paddison, Stephen J.

    2013-02-01

    The membrane-ionomer interface is the critical interlink of the electrodes and catalyst to the polymer electrolyte membrane (PEM); together forming the membrane electrode assembly in current state-of-the-art PEM fuel cells. In this paper, proton conduction through the interface is investigated to understand its effect on the performance of a PEM fuel cell. The water containing domains at this interface were modeled as cylindrical pores/channels with the anionic groups (i.e., -SO3-) assumed to be fixed on the pore wall. The interactions of each species with all other species and an applied external field were examined. Molecular-based interaction potential energies were computed in a small test element of the pore and were scaled up in terms of macroscopic variables. Evolution equations of the density and momentum of the species (water molecules and hydronium ions) were derived within a framework of nonequilibrium thermodynamics. The resulting evolution equations for the species were solved analytically using an order-of-magnitude analysis to obtain an expression for the proton conductivity. Results show that the conductivity increases with increasing water content and pore radius, and strongly depends on the separation distance between the sulfonate groups and their distribution on the pore wall. It was also determined that the conductivity of two similar pores of different radii in series is limited by the pore with the smaller radius.

  12. Impact of thickness on microscopic and macroscopic properties of Fe-Te-Se superconductor thin films

    Directory of Open Access Journals (Sweden)

    N. Zhang

    2015-04-01

    Full Text Available A series of iron based Fe-Te-Se superconductor thin films depositing on 0.7wt% Nb-doped SrTiO3 at substrate temperatures in the 250°C -450°C range by pulsed laser ablation of a constituents well defined precursor FeTe0.55Se0.55 target sample. We study the possible growth mechanism and its influence on the superconductor properties. Experimental results indicate the superconductive and non-superconductive properties are modulated only by the thickness of the thin films through the temperature range. The films appear as superconductor whenever the thickness is above a critical value ∼30nm and comes to be non-superconductor below this value. Relative ratios of Fe to (Te+Se in the films retained Fe/(Te+Se1 for non-superconductor no matter what the film growth temperature was. The effect of film growth temperature takes only the role of modulating the ratio of Te/Se and improving crystallinity of the systems. According to the experimental results we propose a sandglass film growth mechanism in which the interfacial effect evokes to form a Fe rich area at the interface and Se or Te starts off a consecutive filling up process of chalcogenide elements defect sides, the process is significant before the film thickness reaches at ∼30nm.

  13. Phase equilibria in polymer blend thin films: a Hamiltonian approach.

    Science.gov (United States)

    Souche, M; Clarke, N

    2009-12-28

    We propose a Hamiltonian formulation of the Flory-Huggins-de Gennes theory describing a polymer blend thin film. We then focus on the case of 50:50 polymer blends confined between antisymmetric walls. The different phases of the system and the transitions between them, including finite-size effects, are systematically studied through their relation with the geometry of the Hamiltonian flow in phase space. This method provides an easy and efficient way, with strong graphical insight, to infer the qualitative physical behavior of polymer blend thin films.

  14. Fracture and Delamination of Chromium Thin Films on Polymer Substrates

    Science.gov (United States)

    Cordill, M. J.; Taylor, A.; Schalko, J.; Dehm, G.

    2010-04-01

    New emerging technologies in the field of flexible electronic devices require that metal films adhere well and flex with polymer substrates. Common thin film materials used for these applications include copper (Cu) with an adhesion interlayer of chromium (Cr). Copper can be quite ductile and easily move with the polymer substrate. However, Cr is more brittle and fractures at lower strains than Cu. This study aims to examine the fracture and subsequent buckling and delamination of strained Cr films on polyimide (PI). In-situ scanning electron microscope (SEM) straining is used to systematically study the influence of film thickness on fracture and buckling strains. Film fracture and delamination depend on film thickness, and increases in crack and buckle density with decreasing thickness are explored by a shear lag model.

  15. Surface and interface properties of industrially relevant polymers Thin polymer films

    CERN Document Server

    Maccarini, M

    2002-01-01

    This thesis is concerned with the study of some important properties of thin polymer films focusing on two main aspects: the morphologies induced on spin coated polymer films, and swelling and absorption phenomena. Chapter 2 provides an introduction on the theoretical aspects relevant in the field of Polymer Physics: the mixing properties of polymers and solvent, the glass transition temperature, diffusion, surface effects and surface tension, and spin coating. Chapter 3 focuses on the experimental techniques used in this work: Ellipsometry, Quartz Crystal Microbalance, Optical Microscopy and Differential Scanning Calorimetry. Moreover, a description of the material studied is provided. In Chapter 4 a first characterisation of the system investigated is carried out: water absorption and glass transition temperature are measured for bulk material in different moist condition. The refracting indices and the densities of the polymer films are experimentally determined. In Chapter 5 we describe a systematic inves...

  16. Polymer fullerene solution phase behaviour and film formation pathways.

    Science.gov (United States)

    Dattani, Rajeev; Cabral, João T

    2015-04-28

    We report the phase behaviour of polymer/fullerene/solvent ternary mixtures and its consequence for the morphology of the resulting composite thin films. We focus particularly on solutions of polystyrene (PS), C60 fullerene and toluene, which are examined by static and dynamic light scattering, and films obtained from various solution ages and thermal annealing conditions, using atomic force and light microscopy. Unexpectedly, the solution phase behaviour below the polymer overlap concentration, c*, is found to be described by a simple excluded volume argument (occupied by the polymer chains) and the neat C60/solvent miscibility. Scaling consistent with full exclusion is found when the miscibility of the fullerene in the solvent is much lower than that of the polymer, giving way to partial exclusion with more soluble fullerenes (phenyl-C61-butyric acid methyl ester, PCBM) and a less asymmetric solvent (chlorobenzene), employed in photovoltaic devices. Spun cast and drop cast films were prepared from PS/C60/toluene solutions across the phase diagram to yield an identical PS/C60 composition and film thickness, resulting in qualitatively different morphologies in agreement with our measured solution phase boundaries. Our findings are relevant to the solution processing of polymer/fullerene composites (including organic photovoltaic devices), which generally require effective solubilisation of fullerene derivatives and polymer pairs in this concentration range, and the design of well-defined thin film morphologies.

  17. “Electro-Click” on Conducting Polymer Films

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Lind, Johan Ulrik; Daugaard, Anders Egede

    An azide substituted 3,4-ethylenedioxythiophene monomer is polymerised to yield a PEDOT like polymer with available azide groups (Figure 1). The azide groups enable post polymerization functionalization of the conducting polymer using a 1,3 dipolar cycloaddition reaction – also denoted “click...... chemistry”. This facilitates the addition of compounds that can otherwise not withstand the polymerization conditions. Several biological active molecules have been attached and tested on the films. Furthermore conducting polymer microelectrodes can electrochemically generate the catalyst required...... for their own functionalization with high spatial resolution. Interdigitated microelectrodes prepared from the azide-containing conducting polymer were selectively functionalized in sequence by two alkyne-modified fluorophores by control of the applied potentials. “Electro-click” on conducting polymer films...

  18. Controlled release of tocopherols from polymer blend films

    Science.gov (United States)

    Obinata, Noe

    Controlled release packaging has great potential to increase storage stability of foods by releasing active compounds into foods continuously over time. However, a major limitation in development of this technology is the inability to control the release and provide rates useful for long term storage of foods. Better understanding of the factors affecting active compound release is needed to overcome this limitation. The objective of this research was to investigate the relationship between polymer composition, polymer processing method, polymer morphology, and release properties of active compounds, and to provide proof of principle that compound release is controlled by film morphology. A natural antioxidant, tocopherol was used as a model active compound because it is natural, effective, heat stable, and soluble in most packaging polymers. Polymer blend films were produced from combination of linear low density polyethylene (LLDPE) and high density polyethylene (HDPE), polypropylene (PP), or polystyrene (PS) with 3000 ppm mixed tocopherols using conventional blending method and innovative blending method, smart blending with a novel mixer using chaotic advection. Film morphologies were visualized with scanning electron microscopy (SEM). Release of tocopherols into 95% ethanol as a food simulant was measured by UV/Visible spectrophotometry or HPLC, and diffusivity of tocopherols in the polymers was estimated from this data. Polymer composition (blend proportions) and processing methods have major effects on film morphology. Four different types of morphologies, dispersed, co-continuous, fiber, and multilayer structures were developed by either conventional extrusion or smart blending. With smart blending of fixed polymer compositions, different morphologies were progressively developed with fixed polymer composition as the number of rod rotations increased, providing a way to separate effects of polymer composition and morphology. The different morphologies

  19. Macroscopic control of helix orientation in films dried from cholesteric liquid crystalline cellulose nanocrystal suspensions


    OpenAIRE

    2014-01-01

    The intrinsic ability of cellulose nanocrystals (CNCs) to self-organize into films and bulk materials with helical order in a cholesteric liquid crystal is scientifically intriguing and potentially important for the production of renewable multifunctional materials with attractive optical properties. A major obstacle, however, has been the lack of control of helix direction, which results in a defect-rich, mosaic-like domain structure. Herein, a method for guiding the helix during film format...

  20. Process optimization of ultrasonic spray coating of polymer films

    DEFF Research Database (Denmark)

    Bose, Sanjukta; Keller, Stephan Sylvest; Boisen, Anja

    2013-01-01

    In this work we have performed a detailed study of the influence of various parameters on spray coating of polymer films. Our aim is to produce polymer films of uniform thickness (500 nm to 1 μm) and low roughness compared to the film thickness. The coatings are characterized with respect...... these two regimes, where we obtain a film of desired quality. Both with increasing nozzle-substrate distance and temperature, the deposition moves from a wet state to a dry regime. Similar results are also achieved for solvents with low boiling points. Finally, we study film formation during spray coating...... to thickness, roughness (profilometer), and morphology (optical microscopy). Polyvinylpyrrolidone (PVP) is used to do a full factorial design of experiments with selected process parameters such as temperature, distance between spray nozzle and substrate, and speed of the spray nozzle. A mathematical model...

  1. Simulated Space Vacuum Ultraviolet (VUV) Exposure Testing for Polymer Films

    Science.gov (United States)

    Dever, Joyce A.; Pietromica, Anthony J.; Stueber, Thomas J.; Sechkar, Edward A.; Messer, Russell K.

    2002-01-01

    Vacuum ultraviolet (VUV) radiation of wavelengths between 115 and 200 nm produced by the sun in the space environment can cause degradation to polymer films producing changes in optical, mechanical, and chemical properties. These effects are particularly important for thin polymer films being considered for ultra-lightweight space structures, because, for most polymers, VUV radiation is absorbed in a thin surface layer. NASA Glenn Research Center has developed facilities and methods for long-term ground testing of polymer films to evaluate space environmental VUV radiation effects. VUV exposure can also be used as part of sequential simulated space environmental exposures to determine combined damaging effects. This paper will describe the effects of VUV on polymer films and the necessity for ground testing. Testing practices used at Glenn Research Center for VUV exposure testing will be described including characterization of the VUV radiation source used, calibration procedures traceable to the National Institute of Standards and Technology (NIST), and testing techniques for VUV exposure of polymer surfaces.

  2. Patterning Multicomponent Polymer Thin Films via Dynamic Thermal Processing

    Science.gov (United States)

    Singh, Gurpreet

    Bottom-up patterning is gaining increased importance owing to the physical limitations and rising costs of top-down patterning. One example of bottom-up patterning is self-assembling polymer thin films. Although there are several pathways to facilitate polymer thin film self-assembly, this presentation will focus on dynamic thermal field based processes for patterning multicomponent polymer thin films. Dynamic thermal field processing is an attractive roll­to­roll (R2R) amenable directed self­assembly (DSA) method for molecular level organization of multicomponent polymer systems such as block copolymer thin films over large areas without requiring guiding templates. The talk will first outline how parameters such as magnitude of the temperature gradient, velocity of annealing, thermal expansion, and molecular weight of the polymer can be optimized to finely tune the morphology of the block copolymer thin films and also elucidate their associated physical mechanisms. The second part of the talk will outline application of dynamic thermal field processes for fabricating functional nanomaterials and discuss the recent advancements achieved using these processes.

  3. Lattice cluster theory for dense, thin polymer films.

    Science.gov (United States)

    Freed, Karl F

    2015-04-07

    While the application of the lattice cluster theory (LCT) to study the miscibility of polymer blends has greatly expanded our understanding of the monomer scale molecular details influencing miscibility, the corresponding theory for inhomogeneous systems has not yet emerged because of considerable technical difficulties and much greater complexity. Here, we present a general formulation enabling the extension of the LCT to describe the thermodynamic properties of dense, thin polymer films using a high dimension, high temperature expansion. Whereas the leading order of the LCT for bulk polymer systems is essentially simple Flory-Huggins theory, the highly non-trivial leading order inhomogeneous LCT (ILCT) for a film with L layers already involves the numerical solution of 3(L - 1) coupled, highly nonlinear equations for the various density profiles in the film. The new theory incorporates the essential "transport" constraints of Helfand and focuses on the strict imposition of excluded volume constraints, appropriate to dense polymer systems, rather than the maintenance of chain connectivity as appropriate for lower densities and as implemented in self-consistent theories of polymer adsorption at interfaces. The ILCT is illustrated by presenting examples of the computed profiles of the density, the parallel and perpendicular bonds, and the chain ends for free standing and supported films as a function of average film density, chain length, temperature, interaction with support, and chain stiffness. The results generally agree with expected general trends.

  4. Influence of substrate and film thickness on polymer LIPSS formation

    Science.gov (United States)

    Cui, Jing; Nogales, Aurora; Ezquerra, Tiberio A.; Rebollar, Esther

    2017-02-01

    Here we focus on the influence of both, substrate and film thickness on polymer Laser Induced Periodic Surface Structures (LIPSS) formation in polymer films. For this aim a morphological description of ripples structures generated on spin-coated polystyrene (PS) films by a linearly polarized laser beam with a wavelength of 266 nm is presented. The influence of different parameters on the quality and characteristics of the formed laser-induced periodic surface structures (LIPSS) was investigated. We found that well-ordered LIPSS are formed either on PS films thinner than 200 nm or thicker than 400 nm supported on silicon substrates as well as on thicker free standing films. However less-ordered ripples are formed on silicon supported films with intermediate thicknesses in the range of 200-380 nm. The effect of the thermal and optical properties of the substrate on the quality of LIPSS was analyzed. Differences observed in the fluence and number of pulses needed for the onset of surface morphological modifications is explained considering two main effects which are: (1) The temperature increase on polymer surface induced by the action of cumulative laser irradiation and (2) The differences in thermal conductivity between the polymer and the substrate which strongly affect the heat dissipation generated by irradiation.

  5. Convective polymer assembly for the deposition of nanostructures and polymer thin films on immobilized particles

    Science.gov (United States)

    Richardson, Joseph J.; Björnmalm, Mattias; Gunawan, Sylvia T.; Guo, Junling; LiangPresent Address: Csiro Process Science; Engineering, Clayton, Victoria 3168, Australia, Kang; Tardy, Blaise; SekiguchiPresent Address: Graduate School Of Chemical Sciences; Engineering, Hokkaido University, Sapporo, Japan, Shota; Noi, Ka Fung; Cui, Jiwei; EjimaPresent Address: Institute Of Industrial Science, The University Of Tokyo, Tokyo, Japan, Hirotaka; Caruso, Frank

    2014-10-01

    We report the preparation of polymer particles via convective polymer assembly (CPA). Convection is used to move polymer solutions and cargo through an agarose gel that contains immobilized template particles. This method both coats and washes the particles in a process that is amenable to automation, and does not depend on passive diffusion or electrical currents, thus facilitating incorporation of fragile and nanoscale objects, such as liposomes and gold nanoparticles, into the thin polymer films. Template dissolution leads to the formation of stable polymer particles and capsules.We report the preparation of polymer particles via convective polymer assembly (CPA). Convection is used to move polymer solutions and cargo through an agarose gel that contains immobilized template particles. This method both coats and washes the particles in a process that is amenable to automation, and does not depend on passive diffusion or electrical currents, thus facilitating incorporation of fragile and nanoscale objects, such as liposomes and gold nanoparticles, into the thin polymer films. Template dissolution leads to the formation of stable polymer particles and capsules. Electronic supplementary information (ESI) available: Detailed experimental/instrumental information and supporting figures. See DOI: 10.1039/c4nr04348k

  6. RUPTURING OF POLYMER FILMS WITH RUBBING-INDUCED SURFACE DEFECTS

    Institute of Scientific and Technical Information of China (English)

    B.Du; F.C.Xie; Y.J.Wang; O.K.C.Tsui

    2003-01-01

    It has been a long-standing question whether dewetting of polymer film from non-wettable substrate surfaces wherein the bicontinuous morphology never forms in the dewetting film is due to spinodal instability or heterogeneous nucleation. In this experiment, we use a simple method to make the distinction through introduction of topographical defects of the films by rubbing the sample surface with a rayon cloth. Spinodal dewetting is identified for those films that dewet by a characteristic wavevector, q*, independent of the density of rubbing-induced defects. Heterogeneous nucleation, on the other hand, is identified for those with q* increasing with increasing density of defects. Our result shows that PS films on oxide coated silicon with thickness less than ≈ 13 nm are dominated by spinodal dewetting, but the thicker films are dominated by nucleation dewetting. We also confirm that spinodal dewetting does not necessarily lead to a bicontinuous morphology in the dewetting film, contrary to the classic theory of Cahn.

  7. Polymerized rosin: novel film forming polymer for drug delivery.

    Science.gov (United States)

    Fulzele, S V; Satturwar, P M; Dorle, A K

    2002-12-05

    Polymerized rosin (PR) a novel film forming polymer is characterized and investigated in the present study for its application in drug delivery. Films were produced by a casting/solvent evaporation method from plasticizer free and plasticizer containing solutions. Films prepared from different formulations were studied for their mechanical (tensile strength, percent elongation and Young's modulus), water vapour transmission and moisture absorption characteristics. Neat PR films were slightly brittle and posed the problem of breaking during handling. Hydrophobic plasticizers, dibutyl sebacate and tributyl citrate, improved the mechanical properties of free films with both the plasticizers showing significant effects on film elongation. Release of diclofenac sodium (model drug) from coated pellets was sustained with high coating levels. Concentration of plasticizer was found to affect the release profile. PR films plasticized with hydrophobic plasticizers could therefore be used in coating processes for the design of oral sustained delivery dosage forms.

  8. Detecting Airborne Mercury by Use of Polymer/Carbon Films

    Science.gov (United States)

    Shevade, Abhijit; Ryan, Margaret; Homer, Margie; Kisor, Adam; Jewell, April; Yen, Shiao-Pin; Manatt, Kenneth; Blanco, Mario; Goddard, William

    2009-01-01

    Films made of certain polymer/carbon composites have been found to be potentially useful as sensing films for detecting airborne elemental mercury at concentrations on the order of tens of parts per billion or more. That is to say, when the polymer/carbon composite films are exposed to air containing mercury vapor, their electrical resistances decrease by measurable amounts. Because airborne mercury is a health hazard, it is desirable to detect it with great sensitivity, especially in enclosed environments in which there is a risk of a mercury leak from lamps or other equipment. The present effort to develop polymerbased mercury-vapor sensors complements the work reported in NASA Tech Briefs Detecting Airborne Mercury by Use of Palladium Chloride (NPO- 44955), Vol. 33, No. 7 (July 2009), page 48 and De tecting Airborne Mer cury by Use of Gold Nanowires (NPO-44787), Vol. 33, No. 7 (July 2009), page 49. Like those previously reported efforts, the present effort is motivated partly by a need to enable operation and/or regeneration of sensors under relatively mild conditions more specifically, at temperatures closer to room temperature than to the elevated temperatures (greater than 100 C ) needed for regeneration of sensors based on noble-metal films. The present polymer/carbon films are made from two polymers, denoted EYN1 and EYN2 (see Figure 1), both of which are derivatives of poly-4-vinyl pyridine with amine functional groups. Composites of these polymers with 10 to 15 weight percent of carbon were prepared and solution-deposited onto the JPL ElectronicNose sensor substrates for testing. Preliminary test results showed that the resulting sensor films gave measurable indications of airborne mercury at concentrations on the order of tens of parts per billion (ppb) or more. The operating temperature range for the sensing films was 28 to 40 C and that the sensor films regenerated spontaneously, without heating above operating temperature (see Figure 2).

  9. Electrochemical formation of a composite polymer-aluminum oxide film

    Science.gov (United States)

    Runge-Marchese, Jude Mary

    1997-10-01

    The formation of polymer films through electrochemical techniques utilizing electrolytes which include conductive polymer is of great interest to the coatings and electronics industries as a means for creating electrically conductive and corrosion resistant finishes. One of these polymers, polyamino-benzene (polyaniline), has been studied for this purpose for over ten years. This material undergoes an insulator-to-metal transition upon doping with protonic acids in an acid/base type reaction. Review of prior studies dealing with polyaniline and working knowledge of aluminum anodization has led to the development of a unique process whereby composite polymer-aluminum oxide films are formed. The basis for the process is a modification of the anodizing electrolyte which results in the codeposition of polyaniline during aluminum anodization. A second process, which incorporates electrochemical sealing of the anodic layer with polyaniline was also developed. The formation of these composite films is documented through experimental processing, and characterized by way of scientific analysis and engineering tests. Analysis results revealed the formation of unique dual phase anodic films with fine microstructures which exhibited full intrusion of the columnar aluminum oxide structure with polyaniline, indicating the polymer was deposited as the metal oxidation proceeded. An aromatic amine derivative of polyaniline with aluminum sulfate was determined to be the reaction product within the aluminum oxide phase of the codeposited films. Scientific characterization determined the codeposition process yields completely chemically and metallurgically bound composite films. Engineering studies determined the films, obtained through a single step, exhibited superior wear and corrosion resistance to conventionally anodized and sealed films processed through two steps, demonstrating the increased manufacturing process efficiency that can be realized with the modification of the

  10. Molecular Recognition-Mediated Transformation of Single-Chain Polymer Nanoparticles into Crosslinked Polymer Films.

    Science.gov (United States)

    Mahon, Clare S; McGurk, Christopher J; Watson, Scott M D; Fascione, Martin A; Sakonsinsiri, Chadamas; Turnbull, W Bruce; Fulton, David A

    2017-08-14

    We describe single-chain polymer nanoparticles (SCNPs) possessing intramolecular dynamic covalent crosslinks that can transform into polymer films through a molecular recognition-mediated crosslinking process. The SCNPs utilise molecular recognition with surface-immobilised proteins to concentrate upon a substrate, bringing the SCNPs into close spatial proximity with one another and allowing their dynamic covalent crosslinkers to undergo intra- to interpolymer chain crosslinking leading to the formation of polymeric film. SCNPs must possess both the capacity for specific molecular recognition and a dynamic nature to their intramolecular crosslinkers to form polymer films, and an investigation of the initial phase of film formation indicates it proceeds from features which form upon the surface then grow predominantly in the xy directions. This approach to polymer film formation presents a potential method to "wrap" surfaces displaying molecular recognition motifs-which could potentially include viral, cellular and bacterial surfaces or artificial surfaces displaying multivalent recognition motifs-within a layer of polymer film. © 2017 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA.

  11. Correlating the Local Defect-Level Density with the Macroscopic Composition and Energetics of Chalcopyrite Thin-Film Surfaces.

    Science.gov (United States)

    Bröker, Sebastian; Kück, Dennis; Timmer, Alexander; Lauermann, Iver; Ümsür, Bünyamin; Greiner, Dieter; Kaufmann, Christian A; Mönig, Harry

    2015-06-17

    The unusual defect chemistry of polycrystalline Cu(In,Ga)Se2 (CIGSe) thin films is a main issue for a profound understanding of recombination losses in chalcopyrite thin-film solar cells. Especially, impurity-driven passivation of electronic levels due to point defects segregating at the surface and at grain boundaries is extensively debated. By combining current imaging tunneling spectroscopy with photoelectron spectroscopy, the local defect-level density and unusual optoelectronic grain-boundary properties of this material are correlated with the macroscopic energy levels and surface composition. Vacuum annealing of different CIGSe materials provides evidence that Na diffusion from the glass substrate does not affect the surface defect passivation or grain-boundary properties of standard Cu-poor materials. Furthermore, we find no major impact on the observed thermally activated dipole compensation or the accompanying change in surface band bending (up to 0.6 eV) due to Na. In contrast, Cu-rich CIGSe shows an opposing surface defect chemistry with only minor heat-induced band bending. Our results lead to a comprehensive picture, where the highly desirable type inversion at the p/n interface in standard chalcopyrite thin-film solar cells is dominated by band bending within the CIGSe absorber rather than the result of Na impurities or an n-type defect phase segregating at the interface. This is in accordance with recent studies suggesting a surface reconstruction as the origin for Cu depletion and band-gap widening at the surface of chalcopyrite thin films.

  12. Dry-film polymer waveguide for silicon photonics chip packaging.

    Science.gov (United States)

    Hsu, Hsiang-Han; Nakagawa, Shigeru

    2014-09-22

    Polymer waveguide made by dry film process is demonstrated for silicon photonics chip packaging. With 8 μm × 11.5 μm core waveguide, little penalty is observed up to 25 Gbps before or after the light propagate through a 10-km long single-mode fiber (SMF). Coupling loss to SMF is 0.24 dB and 1.31 dB at the polymer waveguide input and output ends, respectively. Alignment tolerance for 0.5 dB loss increase is +/- 1.0 μm along both vertical and horizontal directions for the coupling from the polymer waveguide to SMF. The dry-film polymer waveguide demonstrates promising performance for silicon photonics chip packaging used in next generation optical multi-chip module.

  13. Understanding Local and Macroscopic Electron Mobilities in the Fullerene Network of Conjugated Polymer-based Solar Cells. Time-Resolved Microwave Conductivity and Theory

    Energy Technology Data Exchange (ETDEWEB)

    Aguirre, Jordan C. [Univ. of California, Los Angeles, CA (United States); Arntsen, Christopher D. [Univ. of California, Los Angeles, CA (United States); Hernandez, Samuel [Univ. of California, Los Angeles, CA (United States); Huber, Rachel [Univ. of California, Los Angeles, CA (United States); Nardes, Alexandre M. [National Renewable Energy Lab. (NREL), Golden, CO (United States); Halim, Merissa [Univ. of California, Los Angeles, CA (United States); Kilbride, Daniel [Univ. of California, Los Angeles, CA (United States); Rubin, Yves [Univ. of California, Los Angeles, CA (United States); Tolbert, Sarah H. [Univ. of California, Los Angeles, CA (United States); Kopidakis, Nikos [National Renewable Energy Lab. (NREL), Golden, CO (United States); Schwartz, Benjamin J. [Univ. of California, Los Angeles, CA (United States); Neuhauser, Daniel [Univ. of California, Los Angeles, CA (United States)

    2013-09-23

    The efficiency of bulk heterojunction (BHJ) organic photovoltaics is sensitive to the morphology of the fullerene network that transports electrons through the device. This sensitivity makes it difficult to distinguish the contrasting roles of local electron mobility (how easily electrons can transfer between neighboring fullerene molecules) and macroscopic electron mobility (how well-connected is the fullerene network on device length scales) in solar cell performance. In this work, a combination of density functional theory (DFT) calculations, flash-photolysis time-resolved microwave conductivity (TRMC) experiments, and space-charge-limit current (SCLC) mobility estimates are used to examine the roles of local and macroscopic electron mobility in conjugated polymer/fullerene BHJ photovoltaics. The local mobility of different pentaaryl fullerene derivatives (so-called ‘shuttlecock’ molecules) is similar, so that differences in solar cell efficiency and SCLC mobilities result directly from the different propensities of these molecules to self-assemble on macroscopic length scales. These experiments and calculations also demonstrate that the local mobility of phenyl-C60 butyl methyl ester (PCBM) is an order of magnitude higher than that of other fullerene derivatives, explaining why PCBM has been the acceptor of choice for conjugated polymer BHJ devices even though it does not form an optimal macroscopic network. The DFT calculations indicate that PCBM's superior local mobility comes from the near-spherical nature of its molecular orbitals, which allow strong electronic coupling between adjacent molecules. In combination, DFT and TRMC techniques provide a tool for screening new fullerene derivatives for good local mobility when designing new molecules that can improve on the macroscopic electron mobility offered by PCBM.

  14. Magneto-Photoinduced Absorption in Organic Polymer Films

    Science.gov (United States)

    Gautam, Bhoj; Nguyen, Tho; Ehrenfreund, Eitan; Vardeny, Z. Valy

    2012-02-01

    In order to elucidate the underlying mechanism of magneto-conductivity (MC) in OLEDs we studied magneto-photoinduced absorption (MPA) response in polymer films. The films were based on the MEH-PPV polymer in three different forms, namely: pristine film; film exposed to prolonged UV illumination; and MEH-PPV/PCBM blend having weight ratio 1:1. In pristine film we show that the MPA at low excitation intensity is due to sublevel spin mixing of triplet excitons; whereas at high excitation intensity the MPA is dominated by the triplet-triplet annihilation process. In UV illuminated MEH-PPV films that support photogenerated polarons we show that the MPA is due to sublevel spin-mixing of polaron-pairs via the hyperfine interaction with the closest hydrogen atoms to the chain. This mechanism also explains the MC response of OLED based on MEH-PPV, since its response is similar to that of MPA. Finally we found that the MPA in MEH-PPV/PCBM blend films is dominated by spin mixing of polaron-pair on the polymer and fullerene molecules, via the δg mechanism. Supported by the NSF DMR-1104495, the NSF MRSEC at the UoU, and the BSF program.

  15. Nanostructure investigation of polymer solutions, polymer gels, and polymer thin films

    Science.gov (United States)

    Lee, Wonjoo

    This thesis discusses two systems. One is structured hydrogels which are hydrogel systems based on crosslinked poly((2-dimethylamino)ethyl methacrylate) (PDMAEMA) containing micelles which form nanoscale pores within the PDMAEMA hydrogel. The other is nanoporous block copolymer thin films where solvent selectivity is exploited to create nanopores in PS-b-P4VP thin films. Both of these are multicomponent polymer systems which have nanoscale porous structures. 1. Small angle neutron scattering of micellization of anionic surfactants in water, polymer solutions and hydrogels. Nanoporous materials have been broadly investigated due to the potential for a wide range of applications, including nano-reactors, low-K materials, and membranes. Among those, molecularly imprinted polymers (MIP) have attracted a large amount of interest because these materials resemble the "lock and key" paradigm of enzymes. MIPs are created by crosslinking either polymers or monomers in the presence of template molecules, usually in water. Initially, functional groups on the polymer or the monomer are bound either covalently or noncovalently to the template, and crosslinking results in a highly crosslinked hydrogel. The MIPs containing templates are immersed in a solvent (usually water), and the large difference in the osmotic pressure between the hydrogel and solvent removes the template molecules from the MIP, leaving pores in the polymer network containing functionalized groups. A broad range of different templates have been used ranging from molecules to nanoscale structures inclucing stereoisomers, virus, and micelles. When micelles are used as templates, the size and shape before and after crosslinking is an important variable as micelles are thermodynamic objects whose structure depends on the surfactant concentration of the solution, temperature, electrolyte concentration and polymer concentration. In our research, the first goal is to understand the micellization of anionic

  16. Reversible thermochromic polymer film embedded with fluorescent organogel nanofibers.

    Science.gov (United States)

    Kim, Hyungwoo; Chang, Ji Young

    2014-11-18

    We report a reversible thermochromic nanocomposite polymer film composed of fluorescent organogel fibers and a highly cross-linked polymer matrix. A series of cyano-substituted oligo(p-phenylenevinylene) (CN-OPV) derivatives were synthesized by the reaction of dialdehydes with phenyl or naphthyl acetonitrile under basic conditions. Among the CN-OPV derivatives, NA-DBA having naphtyl moieties and dodecyloxy chains formed a stable organogel in a cross-linkable monomeric solvent (ethylene glycol dimethacrylate). The organogel showed a thermoreversible sol-gel transition, accompanying the emission color change. A nanocomposite polymer film obtained by photopolymerization of the organogel between two quartz plates also exhibited reversible thermochromism. Under 365 nm irradiation, the orange color of the film at 25 °C became yellowish green at 120 °C. The fluorescence spectroscopy, DSC, and microscopy results determined that the thermally reversible self-assembly of NA-DBA occurred in the polymer matrix, resulting in reversible thermochromism. The melted gelator molecules at 120 °C did not diffuse into the polymer matrix probably because of poor interactions of the gelator molecules with the polymer matrix. The NA-DBA molecules dispersed in poly(methyl methacrylate), without forming a supramolecular structure, did not show thermochromism.

  17. The elastic mechanical response of supported thin polymer films.

    Science.gov (United States)

    Chung, Peter C; Glynos, Emmanouil; Green, Peter F

    2014-12-23

    Nanoindentation studies of the mechanical properties of sufficiently thin polymer films, supported by stiff substrates, indicate that the mechanical moduli are generally higher than those of the bulk. This enhancement of the effective modulus, in the thickness range of few hundred nanometers, is indicated to be associated with the propagation and impingement of the indentation tip induced stress field with the rigid underlying substrate; this is the so-called "substrate effect". This behavior has been rationalized completely in terms of the moduli and Poisson's ratios of the individual components, for the systems investigated thus far. Here we show that for thin supported polymer films, in general, information regarding the local chain stiffness and local vibrational constants of the polymers provides an appropriate rationalization of the overall mechanical response of polymers of differing chemical structures and polymer-substrate interactions. Our study should provide impetus for atomistic simulations that carefully account for the role of intermolecular interactions on the mechanical response of supported polymer thin films.

  18. Microwave assisted click chemistry on a conductive polymer film

    DEFF Research Database (Denmark)

    Daugaard, Anders Egede; Hansen, Thomas S.; Larsen, Niels Bent

    2011-01-01

    Microwave (MW) irradiation has been used to accelerate the functionalization of an azide functional poly(3,4-ethylenedioxythiophene) film by click chemistry. The absorption of MW energy by the conductive polymer has been exploited for localized activation of the reaction on the polymer surface....... The method has been applied for anchoring of the chelating agent nitrilotriacetic acid (NTA) on the conductive polymer. The chelating linkage ability of NTA on the surface was investigated through a sandwich ELISA study confirming the selective bonding of a histidine tagged protein....

  19. Femtosecond laser induced index and relief gratings in polymer films

    Institute of Scientific and Technical Information of China (English)

    Yi Dong; Xiaoqiang Yu; Yuming Sun; Yufei Li; Xueyuan Hou; Xian Zhang

    2007-01-01

    A true single-step process suitable for fabrication of micro-periodic structure in polymer films by two photon initiated photopolymerization and laser ablation is presented. By the right choice of the irradiation energy, the irradiated zone is modified or ablated in the 1.44-μm-thick film. The mechanism of grating generation and the potential application of the gratings in integrated optics are discussed.

  20. Process optimization of ultrasonic spray coating of polymer films.

    Science.gov (United States)

    Bose, Sanjukta; Keller, Stephan S; Alstrøm, Tommy S; Boisen, Anja; Almdal, Kristoffer

    2013-06-11

    In this work we have performed a detailed study of the influence of various parameters on spray coating of polymer films. Our aim is to produce polymer films of uniform thickness (500 nm to 1 μm) and low roughness compared to the film thickness. The coatings are characterized with respect to thickness, roughness (profilometer), and morphology (optical microscopy). Polyvinylpyrrolidone (PVP) is used to do a full factorial design of experiments with selected process parameters such as temperature, distance between spray nozzle and substrate, and speed of the spray nozzle. A mathematical model is developed for statistical analysis which identifies the distance between nozzle and substrate as the most significant parameter. Depending on the drying of the sprayed droplets on the substrate, we define two broad regimes, "dry" and "wet". The optimum condition of spraying lies in a narrow window between these two regimes, where we obtain a film of desired quality. Both with increasing nozzle-substrate distance and temperature, the deposition moves from a wet state to a dry regime. Similar results are also achieved for solvents with low boiling points. Finally, we study film formation during spray coating with poly (D,L-lactide) (PDLLA). The results confirm the processing knowledge obtained with PVP and indicate that the observed trends are identical for spraying of other polymer films.

  1. CHEMICALLY DEPOSITED SILVER FILM USED AS A SERS-ACTIVE OVER COATING LAYER FOR POLYMER FILM

    Institute of Scientific and Technical Information of China (English)

    Xiao-ning Liu; Gi Xue; Yun Lu; Jun Zhang; Fen-ting Li; Chen-chen Xue; Stephen Z.D. Cheng

    2001-01-01

    When colloidal silver particles were chemically deposited onto polymer film as an over-coating layer, surfaceenhanced Raman scattering (SERS) spectra could be collected for the surface analysis. SERS measurements of liquid crystal film were successfully performed without disturbing the surface morphology.

  2. Thermal Annealing-Induced Self-Stretching: Fabrication of Anisotropic Polymer Particles on Polymer Films.

    Science.gov (United States)

    Lo, Yu-Ching; Chiu, Yu-Jing; Tseng, Hsiao-Fan; Chen, Jiun-Tai

    2017-10-06

    Designing anisotropic particles of various shapes draws great attention to scientists nowadays. In this work, we develop a facile and simple method to fabricate anisotropic polymer particles from spherical polymer particles. Polyvinyl alcohol (PVA) films spin-coated with polystyrene (PS) microspheres are confined on both sides using binder clips and are heated above the glass transition temperatures of the polymers. During the thermal annealing process, the PS particles sink into the PVA films and transform to anisotropic particles. Depending on the distances to the bound regions, oblate spheroid PS particles or prolate spheroid particles with different aspect ratios can be obtained. The transformation of the particles is mainly driven by the stretching forces and the squeezing forces. The main advantage of this method is that anisotropic particles with different shapes can be fabricated simultaneously on a single film. We expect this novel method can be helpful to various fields including colloids science, suspension rheology, and drug delivery.

  3. Micro-indentation relaxation measurements in polymer thin films

    Science.gov (United States)

    Shinozaki, D. M.; Lu, Y.

    1997-07-01

    A micro-indenter consisting of a piezo-electric driven flat cylindrical punch has been used to measure the dynamic mechanical properties of polystyrene films as thin as 50 μm. The measured viscoelastic response was sensitive to the bonding of the polystyrene to an underlying silicon substrate for films which were thinner than one indenter diameter. The instrument therefore was shown to have practical use in measuring the dynamic mechanical response of polymer films, and the strength of bonding between disparate materials.

  4. Effects of dispersion forces in the instability of polymer films

    Institute of Scientific and Technical Information of China (English)

    Zhao He-Ping; Ophelia K.C.Tsui; Liu Zheng-You

    2006-01-01

    Spontaneous rupture of some polymer films upon heating is commonplace. The very criterion for this instability is the system free energy possessing a negative curvature. Within the framework of full frequency-dependent theory of dispersion forces, we have derived the excess free energy of a typical system-polystyrene film deposited on the silicon substrate. The excess free energy, wavelengths and growth rates are calculate and a comparison is made between the accurate results and the approximate results. It is found that the stability of the film can be tuned by the variation of the thickness of the coating and the retardation effects can be significant sometimes.

  5. Double-electrochromic coordination polymer network films.

    Science.gov (United States)

    Maier, Anna; Cheng, Kalie; Savych, Julia; Tieke, Bernd

    2011-07-01

    Formation and characteristic properties of organized double-electrochromic films consisting of electrochromic poly(4-(2,2':6,2″-terpyridyl)phenyliminofluorene) (P-1)-zinc ion complexes and electrochromic anions are reported. The anions are 2,2'-azino-bis(3-ethylbenzo-thiazoline-6-sulfonate) (ABTS) and poly((4-sulfonatophenyl)iminofluorene) (P-2). The films were prepared upon multiple sequential adsorption of P-1 and the zinc salts of ABTS and P-2 on solid supports using coordinative interactions between the Zn ions and the terpyridine (tpy) ligands. The ABTS and P-2 ions are incorporated in the films via electrostatic forces neutralizing the charge of the complexed divalent zinc (Zn(2+)) ions. The optical, electrochemical, and electrochromic properties of the films are described. Films consisting of the Zn ion complex of P-1 and ABTS are yellow in the neutral state and change their color to brownish gray and finally blue, if anodically oxidized at ∼640 mV vs FOC. Films containing the Zn ion complex of P-1, with P-2 as a counterion, are yellow in the neutral state and change color to dark red and finally blue, if anodically oxidized at ∼450 mV vs FOC. Compared with previously reported films of the Zn ion complex of P-1 with nonelectroactive hexafluorophosphate as the counterion, the new films exhibit faster response times, as well as higher contrast, and the colors in the oxidized state are modified. The films are stable under ambient conditions and might be useful as active layers in electrochromic devices.

  6. Interfacial Slip in Soap Films with Hydrosoluble Polymer

    Science.gov (United States)

    Adelizzi, E. A.; Berg, S.; Troian, S. M.

    2003-11-01

    The thickness of a Newtonian soap film entrained at small capillary number should scale as Ca^2/3 provided the bounding surfaces are rigid. Previous studies show that soap films containing associating, low concentration, high molecular weight (M_w) polymer exhibit strong deviations from this scaling. We report results by laser interferometry of the entrained film thickness for the associating pair SDS/PEO over a large range in polymer molecular weight. Direct comparison to predictions of hydrodynamic models based on viscoelastic behavior shows poor agreement.Modification of the Frankel analysis to account for mobile films through a Navier slip condition yields good agreement. In addition, the slip length Ls increases as M_w^3/5, consistent with a correlation based on a polymer chain size for freely jointed chains with excluded volume effects. Although developed to explain slip at liquid-solid interfaces, the Tolstoi-Larson prediction that Ls scales as the polymer size agrees favorably with our results. Whether the slip behavior is due to Marangoni effects cannot be ruled out.

  7. Structuring of Thin-Film Polymer Mixtures upon Solvent Evaporation

    NARCIS (Netherlands)

    Schaefer, C.; Michels, J. J.; van der Schoot, P.

    2016-01-01

    We theoretically study the impact of solvent evaporation on the dynamics of isothermal phase separation of ternary polymer solutions in thin films. In the early stages we obtain a spinodal length scale that decreases with time under the influence of ongoing evaporation. After that rapid demixing

  8. Polymer thick-film sensors: possibilities for smartcard biometrics

    NARCIS (Netherlands)

    Henderson, N.J.; Papakostas, T.V.; White, N.M.; Hartel, P.H.

    2002-01-01

    In this paper the potential of polymer thick-film sensors are assessed for use as biometric sensors on smartcards. Piezoelectric and piezoresistive sensors have been printed on flexible polyester, then bonded to smartcard blanks. The tactile interaction of a person with these sensors has been invest

  9. Dynamics and structure formation in thin polymer melt films

    Energy Technology Data Exchange (ETDEWEB)

    Seemann, Ralf [Max-Planck-Institut for Dynamics and Self-Organization, Bunsenstrasse 10, 37073 Goettingen (Germany); Herminghaus, Stephan [Max-Planck-Institut for Dynamics and Self-Organization, Bunsenstrasse 10, 37073 Goettingen (Germany); Neto, Chiara [Department of Applied Mathematics, Australian National University, Canberra ACT 0200 (Australia); Schlagowski, Stefan [Department of Applied Physics, University of Ulm, Albert-Einstein-Allee 11, 89069 Ulm (Germany); Podzimek, Daniel [Experimental Physics, Saarland University, 66041 Saarbruecken (Germany); Konrad, Renate [Experimental Physics, Saarland University, 66041 Saarbruecken (Germany); Mantz, Hubert [Experimental Physics, Saarland University, 66041 Saarbruecken (Germany); Jacobs, Karin [Experimental Physics, Saarland University, 66041 Saarbruecken (Germany)

    2005-03-09

    The stability of thin liquid coatings plays a fundamental role in everyday life. We studied the stability conditions of thin (3 to 300 nm) liquid polymer films on various substrates. The key role is played by the effective interface potential {phi} of the system air/film/substrate, which determines the dewetting scenario in case the film is not stable. We describe in this study how to distinguish a spinodal dewetting scenario from heterogeneous and homogeneous dewetting by analysing the emerging structures of the film surface by e.g. Minkowski measures. We also include line tension studies of tiny droplets, showing that the long-range part of {phi} does affect the drop profile, but only very close to the three phase boundary line. The dynamic properties of the films are characterized via various experimental methods: the form of the dewetting front, for example, was recorded by scanning probe microscopy and gives insight into the boundary condition between the liquid and the substrate. We further report experiments probing the viscosity and the glass transition temperature of nm-thick films using e.g. ellipsometry. Here we find that even short-chained polymer melts exhibit a significant reduction of the glass transition temperature as the film thickness is reduced below 100 nm.

  10. Measurement of in-plane thermal conductivity in polymer films

    Science.gov (United States)

    Wei, Qingshuo; Uehara, Chinatsu; Mukaida, Masakazu; Kirihara, Kazuhiro; Ishida, Takao

    2016-04-01

    Measuring the in-plane thermal conductivity of organic thermoelectric materials is challenging but is critically important. Here, a method to study the in-plane thermal conductivity of free-standing films (via the use of commercial equipment) based on temperature wave analysis is explored in depth. This subject method required a free-standing thin film with a thickness larger than 10 μm and an area larger than 1 cm2, which are not difficult to obtain for most solution-processable organic thermoelectric materials. We evaluated thermal conductivities and anisotropic ratios for various types of samples including insulating polymers, undoped semiconducting polymers, doped conducting polymers, and one-dimensional carbon fiber bulky papers. This approach facilitated a rapid screening of in-plane thermal conductivities for various organic thermoelectric materials.

  11. Measurement of in-plane thermal conductivity in polymer films

    Directory of Open Access Journals (Sweden)

    Qingshuo Wei

    2016-04-01

    Full Text Available Measuring the in-plane thermal conductivity of organic thermoelectric materials is challenging but is critically important. Here, a method to study the in-plane thermal conductivity of free-standing films (via the use of commercial equipment based on temperature wave analysis is explored in depth. This subject method required a free-standing thin film with a thickness larger than 10 μm and an area larger than 1 cm2, which are not difficult to obtain for most solution-processable organic thermoelectric materials. We evaluated thermal conductivities and anisotropic ratios for various types of samples including insulating polymers, undoped semiconducting polymers, doped conducting polymers, and one-dimensional carbon fiber bulky papers. This approach facilitated a rapid screening of in-plane thermal conductivities for various organic thermoelectric materials.

  12. Transparent lithiated polymer films for thermal neutron detection

    Science.gov (United States)

    Mabe, Andrew N.; Auxier, John D.; Urffer, Matthew J.; Penumadu, Dayakar; Schweitzer, George K.; Miller, Laurence F.

    2013-09-01

    Novel water-soluble 6Li loaded copolymer scintillation films have been designed and fabricated to detect thermal neutrons. Styrene and maleic anhydride were copolymerized to form an alternating copolymer, then the anhydride functionality was hydrolyzed using 6Li hydroxide. The resulting poly(styrene-co-lithium maleate) was mixed with salicylic acid as a fluor and cast as a thin film from water. The maximum 6Li loading obtained that resulted in a transparent film was 4.36% by mass (6Li to polymer). The optimum fluorescence output was obtained for 11.7% salicylic acid by mass, presumably in the form of lithium salicylate, resulting in an optimum film containing 3.85% by mass of 6Li. A facile and robust synthesis method, film fabrication protocol, photoluminescence results, and scintillation responses are reported herein.

  13. Co-polymer Films for Sensors

    Science.gov (United States)

    Ryan, Margaret A. (Inventor); Homer, Margie L. (Inventor); Yen, Shiao-Pin S. (Inventor); Kisor, Adam (Inventor); Jewell, April D. (Inventor); Shevade, Abhijit V. (Inventor); Manatt, Kenneth S. (Inventor); Taylor, Charles (Inventor); Blanco, Mario (Inventor); Goddard, William A. (Inventor)

    2012-01-01

    Embodiments include a sensor comprising a co-polymer, the co-polymer comprising a first monomer and a second monomer. For some embodiments, the first monomer is poly-4-vinyl pyridine, and the second monomer is poly-4-vinyl pyridinium propylamine chloride. For some embodiments, the first monomer is polystyrene and the second monomer is poly-2-vinyl pyridinium propylamine chloride. For some embodiments, the first monomer is poly-4-vinyl pyridine, and the second monomer is poly-4-vinyl pyridinium benzylamine chloride. Other embodiments are described and claimed.

  14. Preparation and characterization of polymer-clay nanocomposite films

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Polymer/clay nanocomposite films were prepared by means of electrodeposition of aqueous suspension including cathodic electrophoretic acrylic resin (CEAR) and Na+-montmorillonite (NMMT). Studies of XRD,SEM and TEM indicated well-dispersed NMMT platelets in the films prepared. The ideal dispersity achieved was thought to be the result of aqueous compatibility between CEAR molecules and NMMT platelets and the result of the water-involved process as well. The modulus and strength of the polymer/clay nanocomposite coatings tested by tensile testing and nano-indentation were effectively improved compared to those of the virgin CEAR film. In addition,the adhesion strength,flexibility and water-resistance represented by Chinese national standard (GB) kept the best grades.

  15. Anti-biofouling properties of amphiphilic phosphorylcholine polymer films.

    Science.gov (United States)

    Li, Yan; Liu, Cheng-Mei; Yang, Jin-Ying; Gao, Ya-Hui; Li, Xue-Song; Que, Guo-He; Lu, J R

    2011-07-01

    Surfaces of amphiphilic phosphorylcholine polymer (PC1036) prepared by spin-coating were characterized by spectroscopic ellipsometry, water contact angle and atomic force microscopy. The antifouling properties of the PC1036 films to marine benthic diatom Nitzschia closterium MMDL533 were also investigated. The results showed that the dry PC1036 film promoted the adhesion of N. closterium MMDL533 because the hydrophobic lauryl groups were present in the film surface. The 2 h-swelled PC1036 films had excellent anti-fouling properties with extremely low attachment densities and retention densities no matter what the annealing temperature was. The thickness of the coated films lower than 147 Å had a profound effect on the film anti-fouling properties. Otherwise, when the film thickness was higher than that value, there was no more improvement of diatom cell reduction observed. The annealing temperature had only a little effect on the film resistant to diatom adhesion, which might be attributed to two factors including the PC group packing densities in the outer PC layer and the equilibrated water volume fraction in the 2 h-swelled PC1036 films.

  16. Thin film conductive polymer for microactuator and micromuscle applications

    Energy Technology Data Exchange (ETDEWEB)

    Lee, A.P.; Hong, K.; Trevino, J.; Northrup, M.A.

    1994-04-14

    Conductive polymer/polyimide bimorphic microcantilevers have been actuated vertically (out-of-plane) upon the volumetric changes induced by electrochemical doping of the polymer. The microcantilevers that are 200-500 {mu}m in length and 50-100 {mu}m in width can be fully extended from a circularly-curled geometry, and thus generate more than 100 {mu}m displacement. Dynamically the microcantilevers have been driven as fast as 1.2 Hz and the polymer was stable for over a week stored in air and light. Residual stresses in the polymer film is estimated to be as high as 254 MPa, and actuation stresses are as high as 50 MPa.

  17. Highly stretchable polymer semiconductor films through the nanoconfinement effect.

    Science.gov (United States)

    Xu, Jie; Wang, Sihong; Wang, Ging-Ji Nathan; Zhu, Chenxin; Luo, Shaochuan; Jin, Lihua; Gu, Xiaodan; Chen, Shucheng; Feig, Vivian R; To, John W F; Rondeau-Gagné, Simon; Park, Joonsuk; Schroeder, Bob C; Lu, Chien; Oh, Jin Young; Wang, Yanming; Kim, Yun-Hi; Yan, He; Sinclair, Robert; Zhou, Dongshan; Xue, Gi; Murmann, Boris; Linder, Christian; Cai, Wei; Tok, Jeffery B-H; Chung, Jong Won; Bao, Zhenan

    2017-01-06

    Soft and conformable wearable electronics require stretchable semiconductors, but existing ones typically sacrifice charge transport mobility to achieve stretchability. We explore a concept based on the nanoconfinement of polymers to substantially improve the stretchability of polymer semiconductors, without affecting charge transport mobility. The increased polymer chain dynamics under nanoconfinement significantly reduces the modulus of the conjugated polymer and largely delays the onset of crack formation under strain. As a result, our fabricated semiconducting film can be stretched up to 100% strain without affecting mobility, retaining values comparable to that of amorphous silicon. The fully stretchable transistors exhibit high biaxial stretchability with minimal change in on current even when poked with a sharp object. We demonstrate a skinlike finger-wearable driver for a light-emitting diode. Copyright © 2017, American Association for the Advancement of Science.

  18. On near-free-surface dynamics of thin polymer films

    Science.gov (United States)

    Qi, Dongping

    In the present studies of four projects we developed several novel techniques to investigate near-free-surface dynamics of thin polymer films. In the first project, we studied the dynamical properties of the first 2-3 nm region of glassy isotactic poly (methyl methacrylate) (i-PMMA) films by means of the nano surface hole relaxation technique. We found that for the measured surface relaxation times there is a strong substrate property dependence, which can propagate into i-PMMA films for a distance of more than 100nm. An unexpected molecular weight (Mw) dependence of the near surface relaxation time is found for thick i-PMMA films, which, together with the finding that the free surface could be assigned a local surface glass transition temperature of ˜40K below bulk T g, indicates a viscous liquid regime while the rest of the underneath bulk part is in the glassy state. In the second project, the nano gold sphere embedding technique was used to study the nearfree-surface dynamics of polystyrene (PS) films within wide temperature and time windows. Three sections of measurements are conducted in this project. In the first section, we studied the Mw dependence of the near-free-surface dynamics of PS films and found that at temperatures above bulk Tg there exists a Mw dependence which can be explained using the Rouse dynamics for melt polymers. However, at a temperature of 16K below bulk T g no w M dependence is discernible, which is in contrast to that for i-PMMA films where even at a temperature of ˜36K below bulk Tg a Mw dependence of the near free surface dynamics is still observed. In the second section of this work, we studied the nano gold sphere embedding behavior within a wide temperature and time window, and for the first time the depth dependence of the near-free-surface dynamics with the nanometer scale resolution was observed. By an embedding-model-free data analysis the results show that when the measurement temperature is above a temperature of ˜378K

  19. Surface analysis of the selective excimer laser patterning of a thin PEDOT:PSS film on flexible polymer films

    Science.gov (United States)

    Schaubroeck, David; De Smet, Jelle; Willems, Wouter; Cools, Pieter; De Geyter, Nathalie; Morent, Rino; De Smet, Herbert; Van Steenbeerge, Geert

    2016-07-01

    Fast patterning of highly conductive polymers like PEDOT:PSS (poly (3,4-ethylene dioxythiophene): polystyrene sulfonate) with lasers can contribute to the development of industrial production of liquid crystal displays on polymer foils. In this article, the selective UV laser patterning of a PEDOT:PSS film on flexible polymer films is investigated. Based on their optical properties, three polymer films are investigated: polyethylene terephthalate (PET), polymethyl methacrylate (PMMA) and cellulose triacetate (TAC). Ablation parameters for a 110 nm PEDOT:PSS film on these polymer films are optimized. A detailed study of the crater depth, topography and surface composition are provided using optical profilometry, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The electrical insulation of the lines is measured and correlated to the crater analyses for different laser settings. Finally, potential ablation parameters for each of the polymer films are derived.

  20. Electrodeposited polymer encapsulated nickel sulphide thin films: frequency switching material

    Energy Technology Data Exchange (ETDEWEB)

    Jana, Sumanta, E-mail: sumantajana85@gmail.com [Department of Chemistry, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India); Mukherjee, Nillohit [Centre of Excellence for Green Energy and Sensor Systems, Bengal Engineering and Science University, Howrah 711103, WB (India); Chakraborty, Biswajit [Department of Chemistry, Vivekananda Mahavidyalay, Burdwan 713103, WB (India); Mitra, Bibhas Chandra [Department of Physics, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India); Mondal, Anup, E-mail: anupmondal2000@yahoo.co.in [Department of Chemistry, Bengal Engineering and Science University, Botanic Garden, Howrah 711103, WB (India)

    2014-05-01

    Graphical abstract: Polyvinylpyrrolidone encapsulated NiS thin films were synthesized electrochemically. The light induced frequency switching study of the synthesized material was carried out and it was observed that the films performed well as a switching device under 1 Sun illumination. This pulse generation within an insulating polymer encapsulated semicondctor matrix (PVP NiS) might be due to surface covering which leads to reduction of recombination process. Highlights: • PVP-NiS thin films were electrochemically synthesized. • Encapsulation of PVP causes surface modification of NiS by reducing surface states. • The synthesized thin films were used as frequency switching material which generates ~ 50 Hz frequency under 1 Sun irradiation. Abstract: Polyvinylpyrrolidone (PVP) encapsulated nickel sulfide (NiS) thin films have been synthesized electrochemically from aqueous solution of hydrated nickel chloride (NiCl₂, 6H₂O), thioacetamide (CH₃C(S) NH₂) (TAA) and polyvinylpyrrolidone (PVP). Surface modification of nickel sulfide (NiS) thin films was achieved by this polymer encapsulation. X-ray diffraction (XRD), high resolution transmission electron microscope (HRTEM), field emission scanning electron microscopy (FESEM) and Energy dispersive X-radiation (EDAX) techniques were used for the characterization of thin films. Infrared spectroscopy (IR) confirmed the formation of polymer encapsulated semiconductor. Frequency switching generation study shows that the encapsulated material could be used as a frequency switching device that generates a frequency ~ 50 Hz under 1 Sun illumination. Encapsulation with PVP causes surface modification that reduces the surface states and barrier height. As a result, the width of the depletion region decreases. So the number of electron-hole pairs increases. Consequently, the number of excitons and exciton related emission increases and this leads to reduction of recombination process and shows photo induced

  1. A conducting polymer film stronger than aluminum.

    Science.gov (United States)

    Shi, G; Jin, S; Xue, G; Li, C

    1995-02-17

    Polythiophene (Pth) was electrochemically deposited onto stainless steel substrate from freshly distilled boron fluoride-ethyl ether containing 10 millimoles of thiophene per liter. The free-standing Pth film obtained at an applied potential of 1.3 volts (versus Ag/AgCl) had a conductivity of 48.7 siemens per centimeter. Its tensile strength (1200 to 1300 kilograms per square centimeter) was greater than that of aluminium (1000 to 1100 kilograms per square centimeter). This Pth film behaves like a metal sheet and can be easily cut into various structures with a knife or a pair of scissors.

  2. Nanodiamond-polymer nanoparticle composites and their thin films

    Science.gov (United States)

    Attia, N. F.; Rao, J. P.; Geckeler, K. E.

    2014-04-01

    Nanodiamonds obtained from detonation processes have received a great deal of attention during the past decades because of their unique properties and applications. The dispersion of nanodiamond particles can be achieved by different methods including the use of polymer nanoparticles. Here, we describe the dispersion of nanodiamonds in conjunction with sonication using poly(vinylpyrrolidone) nanoparticles with a particle size range of 23.3-61.3 nm, providing a good, economic, and efficient method for the dispersion. The average particle size was found to be 37.5 nm, as confirmed by transmission electron microscopy. The interaction between the nanodiamonds and polymer nanoparticles was characterized by FTIR spectroscopy and the effect of the polymer nanoparticle concentration, sonication time, and frequency on the dispersion process of nanodiamonds is highlighted. In addition, we prepared thin films of nanodiamond-polymer composites with different nanodiamond contents that showed good nanodiamond dispersion. The thin film can act as a UV filter and is transparent in the visible region. The thin films of nanodiamond-poly(vinylpyrrolidone) nanoparticles were characterized by SEM and UV-Vis spectroscopy.

  3. Soiling and Cleaning of Polymer Film Solar Reflectors

    Directory of Open Access Journals (Sweden)

    Christopher Sansom

    2016-11-01

    Full Text Available This paper describes the accelerated ageing of commercially available silvered polymer film by contact cleaning using brushes and water in the presence of soiling created by dust and sand particles. These conditions represent cleaning regimes in real concentrating solar power (CSP solar fields in arid environments, where contact cleaning using brushes and water is often required to clean the reflecting surfaces. Whilst suitable for glass reflectors, this paper discusses the effects of these established cleaning processes on the optical and visual characteristics of polymer film surfaces, and then describes the development of a more benign but effective contact cleaning process for cleaning polymer reflectors. The effects of a range of cleaning brushes are discussed, with and without the presence of water, in the presence of sand and dust particles from selected representative locations. The experiments were repeated using different experimental equipment at Plataforma Solar de Almería (PSA in Spain and Cranfield University in the UK. The results highlight differences that are attributable to the experimental methods used. Reflectance measurements and visual inspection show that a soft cleaning brush with a small amount of water, used in a cleaning head with both linear and rotational motion, can clean polymer film reflecting surfaces without inflicting surface damage or reducing specular reflectance.

  4. Deformation Hysteresis of Electrohydrodynamic Patterning on a Thin Polymer Film.

    Science.gov (United States)

    Yang, Qingzhen; Li, Ben Q; Tian, Hongmiao; Li, Xiangming; Shao, Jinyou; Chen, Xiaoliang; Xu, Feng

    2016-07-13

    Electrohydrodynamic patterning is a technique that enables micro/nanostructures via imposing an external voltage on thin polymer films. In this investigation, we studied the electrohydrodynamic patterning theoretically and experimentally, with special interest focused on the equilibrium state. It is found that the equilibrium structure height increases with the voltage. In addition, we have observed, and believe it to be the first time, a hysteresis phenomenon exists in the relationship between the voltage and structure height. With an increase in the voltage, a critical value (the first critical voltage) is noticed, above which the polymer film would increase dramatically until it comes into contact with the template. However, with a decrease in the voltage, a smaller voltage (the second critical voltage) is needed to detach the polymer from the template. The mismatch of the first and second critical voltages distorts the voltage-structure height curve into an "S" shape. Such a phenomenon is verified for three representative templates and also by experiments. Furthermore, the effects of some parameters (e.g., polymer film thickness and dielectric constant) on this hysteresis phenomenon are also discussed.

  5. Film-thickness dependence of structure formation in ultra-thin polymer blend films

    CERN Document Server

    Gutmann, J S; Stamm, M

    2002-01-01

    We investigated the film-thickness dependence of structure formation in ultra-thin polymer blend films prepared from solution. As a model system we used binary blends of statistical poly(styrene-co-p-bromostyrene) copolymers of different degrees of bromination. Ultra-thin-film samples differing in miscibility and film thickness were prepared via spin coating of common toluene solutions onto silicon (100) substrates. The resulting morphologies were investigated with scanning force microscopy, reflectometry and grazing-incidence scattering techniques using both X-rays and neutrons in order to obtain a picture of the sample structure at and below the sample surface. (orig.)

  6. MACROSCOPIC RIVERS

    NARCIS (Netherlands)

    VANDENBERG, IP

    1991-01-01

    We present a mathematical model for the ''river-phenomenon'': striking concentrations of trajectories of ordinary differential equations. This model of ''macroscopic rivers'' is formulated within nonstandard analysis, and stated in terms of macroscopes and singular perturbations. For a subclass, the

  7. Polymer Nanofibers with Outstanding Thermal Conductivity and Thermal Stability: Fundamental Linkage between Molecular Characteristics and Macroscopic Thermal Properties

    CERN Document Server

    Zhang, Teng; Luo, Tengfei

    2014-01-01

    Polymer nanofibers with high thermal conductivities and outstanding thermal stabilities are highly desirable in heat transfer-critical applications such as thermal management, heat exchangers and energy storage. In this work, we unlock the fundamental relations between the thermal conductivity and thermal stability of polymer nanofibers and their molecular characteristics by studying the temperature-induced phase transitions and thermal transport of a series of polymer nanofibers. Ten different polymer nanofibers with systematically chosen molecular structures are studied using large scale molecular dynamics simulations. We found that high thermal conductivity and good thermal stability can be achieved in polymers with rigid backbones, exemplified by {\\pi}-conjugated polymers, due to suppressed segmental rotations and large phonon group velocities. The low probability of segmental rotation does not only prevent temperature-induced phase transition but also enables long phonon mean free paths due to reduced di...

  8. Conductive Polymer Porous Film with Tunable Wettability and Adhesion

    Directory of Open Access Journals (Sweden)

    Yuqi Teng

    2015-04-01

    Full Text Available A conductive polymer porous film with tunable wettability and adhesion was fabricated by the chloroform solution of poly(3-hexylthiophene (P3HT and [6,6]-phenyl-C61-butyricacid-methyl-ester (PCBM via the freeze drying method. The porous film could be obtained from the solution of 0.8 wt%, whose pore diameters ranged from 50 nm to 500 nm. The hydrophobic porous surface with a water contact angle (CA of 144.7° could be transferred into a hydrophilic surface with CA of 25° by applying a voltage. The water adhesive force on the porous film increased with the increase of the external voltage. The electro-controllable wettability and adhesion of the porous film have potential application in manipulating liquid collection and transportation.

  9. TWO-LAYER MODEL DESCRIPTION OF POLYMER THIN FILM DYNAMICS

    Institute of Scientific and Technical Information of China (English)

    Dong-dong Peng; Ran-xing Nancy Li; Chi-hang Lam; Ophelia K.C.Tsui

    2013-01-01

    Experiments in the past two decades have shown that the glass transition temperature of polymer films can become noticeably different from that of the bulk when the film thickness is decreased below ca.100 nm.It is broadly believed that these observations are caused by a nanometer interfacial layer with dynamics faster or slower than that of the bulk.In this paper,we examine how this idea may be realized by using a two-layer model assuming a hydrodynamic coupling between the interfacial layer and the remaining,bulk-like layer in the film.Illustrative examples will be given showing how the two-layer model is applied to the viscosity measurements of polystyrene and polymethylmethacrylate films supported by silicon oxide,where divergent thickness dependences are observed.

  10. Photo-Induced Magnetic Anisotropy of Polymer Film Containing Azobenzene Organic Free Radical Group

    Institute of Scientific and Technical Information of China (English)

    徐则达; 张勇; 陈小芳; 范星河; 宛新华; 周其凤

    2003-01-01

    The forward degenerate four-wave mixing geometry was employed to induce microstructure in an organic free radical azobenzene polymer film. Before irradiated with Ar+ laser beams (λ = 514.5 nm), the azobenzene organic free radical polymer exhibits magnetic isotropic measured by superconducting quantum interference device. After photo-induced microstructure, the polymer film becomes magnetic anisotropy. When the applied magnetic field H = 50 Gauss, the magnetization along the normal direction of the polymer film is Mz = 5.5 × 10-5 emu/g,which is larger than Mx = 4.1 × 10-5 emu/g in the direction parallel to the polymer film.

  11. Transparent lithiated polymer films for thermal neutron detection

    Energy Technology Data Exchange (ETDEWEB)

    Mabe, Andrew N., E-mail: andrew.n.mabe@gmail.com [Department of Chemistry, University of Tennessee, Knoxville, TN 37996 (United States); Auxier, John D. [Department of Chemistry, University of Tennessee, Knoxville, TN 37996 (United States); Urffer, Matthew J. [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Penumadu, Dayakar [Department of Civil and Environmental Engineering, University of Tennessee, Knoxville, TN 37996 (United States); Schweitzer, George K. [Department of Chemistry, University of Tennessee, Knoxville, TN 37996 (United States); Miller, Laurence F. [Department of Nuclear Engineering, University of Tennessee, Knoxville, TN 37996 (United States)

    2013-09-11

    Novel water-soluble {sup 6}Li loaded copolymer scintillation films have been designed and fabricated to detect thermal neutrons. Styrene and maleic anhydride were copolymerized to form an alternating copolymer, then the anhydride functionality was hydrolyzed using {sup 6}Li hydroxide. The resulting poly(styrene-co-lithium maleate) was mixed with salicylic acid as a fluor and cast as a thin film from water. The maximum {sup 6}Li loading obtained that resulted in a transparent film was 4.36% by mass ({sup 6}Li to polymer). The optimum fluorescence output was obtained for 11.7% salicylic acid by mass, presumably in the form of lithium salicylate, resulting in an optimum film containing 3.85% by mass of {sup 6}Li. A facile and robust synthesis method, film fabrication protocol, photoluminescence results, and scintillation responses are reported herein. -- Highlights: • A transparent polymer scintillator containing 3.85 wt% {sup 6}Li has been synthesized. • This class of polymeric thermal neutron scintillation detector is water-soluble. • Salicylic acid, presumably in the form of lithium salicylate, is used as a fluor. • The material emits 373 photons/α ({sup 241}Am) and an average of 139 photons/β ({sup 36}Cl). • The material emits 360 photons per thermal neutron capture event.

  12. Microstructure Evolution during Solvent Evaporation from Thin Film Polymer Mixtures

    Science.gov (United States)

    Clarke, Nigel; Souche, Mireille; Buxton, Gavin

    2009-03-01

    We present simulations of the phase separation dynamics in a thin film polymer blend solution subject to solvent evaporation [1]. If the upper and lower surfaces are neutral with respect to the different components, we find that as the solvent diffuses through the film, and evaporates from the surface, phase separation becomes energetically favourable progressively throughout the film. This produces an ordering front which propagates through the film and leaves an ordered lateral morphology in its wake. In order to understand microstructure evolution if the surface interactions are strong enough that the film initially separates into a two layers, we have perfomed a linear analysis of the Marangoni instability of a deformable interface between two fluid layers of finite depths, submitted to a gradient of solvent concentration induced by the evaporation [2]. Qualitative comparison with experimental observations of spin-coating processes of solution of two immiscible polymers are then performed, yielding satisfactory agreement.[0pt] [1] G. A. Buxton and N.Clarke, Europhysics Letters, 78, 56006, 2007.[0pt] [2] M. Souche and N. Clarke, European Physical Journal E, in press.

  13. Convergence to Self-Similar Regimes in Thin Polymer Films

    Science.gov (United States)

    Benzaquen, Michael; Salez, Thomas; Raphaël, Elie; Elie Raphaël Team; Kari Dalnoki-Veress Team

    2013-03-01

    The surface of a thin liquid film with nonconstant curvature is unstable, as the Laplace pressure drives a flow mediated by viscosity. Recent experiments and theory applied to stepped polymer films have shown excellent agreement and provide a technique for the study of polymer confinement, the glass transition, and slip at the fluid substrate interface to name a few. The thin film equation governs the evolution of the free surface profile in the lubrication approximation. Despite many efforts, this equation remains only partially solved. We present an analytical and numerical study of the thin film equation. Linearising this equation enables us to derive the Green's function of the problem and therefore obtain a complete set of solutions. We show that the solutions of the problem with equilibrium boundary conditions uniformly converge in time towards a first kind self-similar universal attractor. A numerical study enables us to extend our results to the nonlinear thin film equation. Laboratoire Physico-Chimie Théorique, UMR CNRS 7083 Gulliver. ESPCI, 10 rue Vauquelin, 75005, Paris, France.

  14. Entanglement effects in capillary waves on liquid polymer films.

    Science.gov (United States)

    Jiang, Zhang; Mukhopadhyay, Mrinmay K; Song, Sanghoon; Narayanan, Suresh; Lurio, L B; Kim, Hyunjung; Sinha, Sunil K

    2008-12-12

    Overdamped surface capillary wave relaxations on molten polymer films were measured using x-ray photon correlation spectroscopy. We found a transition from a single through a stretched to another single exponential regime as the temperature is decreased from well above to near the bulk glass transition temperature. A universal scaling of the dynamics was discovered over a wide range of film thicknesses, temperatures, and molecular weights (except in the multiple relaxation regime). These observations are justified by hydrodynamic theory and the time-temperature superposition principle by considering an effective viscosity instead of the bulk zero shear viscosity.

  15. Thin Films Formed from Conjugated Polymers with Ionic, Water-Soluble Backbones.

    Science.gov (United States)

    Voortman, Thomas P; Chiechi, Ryan C

    2015-12-30

    This paper compares the morphologies of films of conjugated polymers in which the backbone (main chain) and pendant groups are varied between ionic/hydrophilic and aliphatic/hydrophobic. We observe that conjugated polymers in which the pendant groups and backbone are matched, either ionic-ionic or hydrophobic-hydrophobic, form smooth, structured, homogeneous films from water (ionic) or tetrahydrofuran (hydrophobic). Mismatched conjugated polymers, by contrast, form inhomogeneous films with rough topologies. The polymers with ionic backbone chains are conjugated polyions (conjugated polymers with closed-shell charges in the backbone), which are semiconducting materials with tunable bad-gaps, not unlike uncharged conjugated polymers.

  16. Elasto-Optical Properties of Thin Polymer Films by Prism Coupling Technique

    Science.gov (United States)

    Ay, Feridun; Agan, Sedat; Kocabas, Askin; Aydinli, Atilla

    2004-05-01

    Reliable measurement of stress dependent refractive index of thin polymer films has been achieved. The effect of the applied stress on the refractive index and birefringence of the films was investigated. The out-of-plane elastic moduli of the thin polymer films were deduced by using the same prism coupling setup. Three dimensional finite element method (FEM) analysis was used to obtain the principal stresses for each polymer film and combining them with the stress dependent refractive index measurements, the elasto-optic coefficients of the polymer films were determined, for the first time.

  17. Intricacies of Polymer Dewetting: Nanoscaled Architectures for the Tailored Control of Polystyrene Thin Film Stability

    Science.gov (United States)

    Cheung, Justin; Sen, Mani; Chen, Zhizhao; Jiang, Naisheng; Endoh, Maya; Koga, Tadanori; Satija, Sushil

    Recently, structural properties of polymer thin films have garnered attention for their relevance in the fields of organic photovoltaics and biosensors. The dewetting of polymer films poses an obstacle in the face of widespread implementation. For this study, we show that adsorbed polymer chains on a substrate surface play crucial roles in film stability. Polystyrene (PS) thin films (20 nm in thickness) with different molecular weights (Mw) on silicon (Si) substrates were used as a model. The PS films were annealed at high temperatures for several days, and Mw dependence on film stability was evidenced. At the same time, the annealed PS films were leached with a good solvent and the residue films (i.e., irreversibly adsorbed layers) were characterized by x-ray reflectivity (XR). We reveal strong correlation between film stability and two different interfacial structures of the adsorbed polymer chains: their opposing wettability against chemically identical free polymer chains results in a wetting-dewetting transition at the adsorbed polymer-free polymer interface. This is a unique aspect of polymer thin film stability and may be generalizable to other polymer systems regardless of the magnitude of solid-polymer attractive interactions. We acknowledge the financial support of NSF Grant (CMMI-1332499).

  18. RUPTURING OF POLYMER FILMS WITH RUBBING—INDUCED SURFACE DEFECTS

    Institute of Scientific and Technical Information of China (English)

    B.Du; F.C.Xie; Y.J.Wang; O.K.C.Tsui; O.K.C.Tsui

    2003-01-01

    It has been a long-standing question whether dewetting of polymer film from non-wettable substrate surfaces wherein the bicontinuous morphology never forms in the dewetting film is due to spinodal instability or heterogeneous nucleation.In this experiment,we use a simple method to make the distinction through introduction of topographical defects of the films by rubbing the sample surface with a rayon cloth.Spinodal dewetting is identified for those films that dewet by a characteristic wavevector,q,independent of the density of rubbing-induced defects.Heterogeneous nucleation,on the other hand,is identified for those with q increasing with increasing density of defects.Our result shows that PS films on oxide coated silicon with thickness less than≈13nm are dominated by spinodal dewetting,but the thicker films are dominated by nucleation dewetting.We also confirm that spinodal dewetting does not necessarily lead to a bicontinuous morphology in the dewetting film,contrary to the classic theory of Cahn.

  19. Polymer Substrates For Lightweight, Thin-Film Solar Cells

    Science.gov (United States)

    Lewis, Carol R.

    1993-01-01

    Substrates survive high deposition temperatures. High-temperature-resistant polymers candidate materials for use as substrates of lightweight, flexible, radiation-resistant solar photovoltaic cells. According to proposal, thin films of copper indium diselenide or cadmium telluride deposited on substrates to serve as active semiconductor layers of cells, parts of photovoltaic power arrays having exceptionally high power-to-weight ratios. Flexibility of cells exploited to make arrays rolled up for storage.

  20. Thin aligned organic polymer films for liquid crystal devices

    CERN Document Server

    Foster, K E

    1997-01-01

    This project was designed to investigate the possibility of producing alignment layers for liquid crystal devices by cross-linking thin films containing anisotropic polymer bound chromophores via irradiation with polarised ultraviolet light. Photocross-linkable polymers find use in microelectronics, liquid crystal displays, printing and UV curable lacquers and inks; so there is an increasing incentive for the development of new varieties of photopolymers in general. The synthesis and characterisation of two new photopolymers that are suitable as potential alignment layers for liquid crystal devices are reported in this thesis. The first polymer contains the anthracene chromophore attached via a spacer unit to a methacrylate backbone and the second used a similarly attached aryl azide group. Copolymers of the new monomers with methyl methacrylate were investigated to establish reactivity ratios in order to understand composition drift during polymerisation.

  1. Scalable fabrication of multifunctional freestanding carbon nanotube/polymer composite thin films for energy conversion.

    Science.gov (United States)

    Li, Xiaokai; Gittleson, Forrest; Carmo, Marcelo; Sekol, Ryan C; Taylor, André D

    2012-02-28

    Translating the unique properties of individual single-walled carbon nanotubes (SWNTs) to the macroscale while simultaneously incorporating additional functionalities into composites has been stymied by inadequate assembly methods. Here we describe a technique for developing multifunctional SWNT/polymer composite thin films that provides a fundamental engineering basis to bridge the gap between their nano- and macroscale properties. Selected polymers are infiltrated into a Mayer rod coated conductive SWNT network to fabricate solar cell transparent conductive electrodes (TCEs), fuel cell membrane electrode assemblies (MEAs), and lithium ion battery electrodes. Our TCEs have an outstanding optoelectronic figure of merit σ(dc)/σ(ac) of 19.4 and roughness of 3.8 nm yet are also mechanically robust enough to withstand delamination, a step toward scratch resistance necessary for flexible electronics. Our MEAs show platinum utilization as high as 1550 mW/mg(Pt), demonstrating our technique's ability to integrate ionic conductivity of the polymer with electrical conductivity of the SWNTs at the Pt surface. Our battery anodes, which show reversible capacity of ∼850 mAh/g after 15 cycles, demonstrate the integration of electrode and separator to simplify device architecture and decrease overall weight. Each of these applications demonstrates our technique's ability to maintain the conductivity of SWNT networks and their dispersion within a polymer matrix while concurrently optimizing key complementary properties of the composite. Here, we lay the foundation for the assembly of nanotubes and nanostructured components (rods, wires, particles, etc.) into macroscopic multifunctional materials using a low-cost and scalable solution-based processing technique.

  2. Nanoparticles of conjugated polymers prepared from phase-separated films of phospholipids and polymers for biomedical applications.

    Science.gov (United States)

    Yoon, Jungju; Kwag, Jungheon; Shin, Tae Joo; Park, Joonhyuck; Lee, Yong Man; Lee, Yebin; Park, Jonghyup; Heo, Jung; Joo, Chulmin; Park, Tae Jung; Yoo, Pil J; Kim, Sungjee; Park, Juhyun

    2014-07-09

    Phase separation in films of phospholipids and conjugated polymers results in nanoassemblies because of a difference in the physicochemical properties between the hydrophobic polymers and the polar lipid heads, together with the comparable polymer side-chain lengths to lipid tail lengths, thus producing nanoparticles of conjugated polymers upon disassembly in aqueous media by the penetration of water into polar regions of the lipid heads.

  3. Controlled antiseptic release by alginate polymer films and beads.

    Science.gov (United States)

    Liakos, Ioannis; Rizzello, Loris; Bayer, Ilker S; Pompa, Pier Paolo; Cingolani, Roberto; Athanassiou, Athanassia

    2013-01-30

    Biodegradable polymeric materials based on blending aqueous dispersions of natural polymer sodium alginate (NaAlg) and povidone iodine (PVPI) complex, which allow controlled antiseptic release, are presented. The developed materials are either free standing NaAlg films or Ca(2+)-cross-linked alginate beads, which properly combined with PVPI demonstrate antibacterial and antifungal activity, suitable for therapeutic applications, such as wound dressing. Glycerol was used as the plasticizing agent. Film morphology was studied by optical and atomic force microscopy. It was found that PVPI complex forms well dispersed circular micro-domains within the NaAlg matrix. The beads were fabricated by drop-wise immersion of NaAlg/PVPI/glycerol solutions into aqueous calcium chloride solutions to form calcium alginate beads encapsulating PVPI solution (CaAlg/PVPI). Controlled release of PVPI was possible when the composite films and beads were brought into direct contact with water or with moist media. Bactericidal and fungicidal properties of the materials were tested against Escherichia coli bacteria and Candida albicans fungi. The results indicated very efficient antibacterial and antifungal activity within 48 h. Controlled release of PVPI into open wounds is highly desired in clinical applications to avoid toxic doses of iodine absorption by the wound. A wide variety of applications are envisioned such as external and internal wound dressings with controlled antiseptic release, hygienic and protective packaging films for medical devices, and polymer beads as water disinfectants.

  4. Electrochemically polymerized conjugated polymer films: Stability improvement and surface functionalization

    Science.gov (United States)

    Wei, Bin

    Conjugated polymers have been widely used in various applications including organic solar cells, electrochromic devices, chemical sensors, and biomedical devices. Poly(3,4-ethylenedioxythiophene) (PEDOT) and its derivatives have received considerable interest because of their low oxidation potential, relatively high chemical stability, and high conductivity. Electrochemical deposition is a convenient method for precisely fabricating conjugated polymer thin films. Here, we report the stability improvement and surface functionalization of electrochemically polymerized PEDOT films. The long-term performance of PEDOT coatings is limited by their relatively poor stability on various inorganic substrates. Two different methods were used to improve the stability of PEDOT coatings, one involved using carboxylic acid functionalized EDOT (EDOT-acid) as adhesion promoter. EDOT-acid molecules were chemically bonded onto activated metal oxide substrates via chemisorption. PEDOT was then polymerized onto the EDOT-acid modified substrates, forming covalently bonded coatings. An aggressive ultrasonication test confirmed the significantly improved adhesion of the PEDOT films on electrodes with EDOT-acid treatment over those without treatment. The other method was to use an octa-ProDOT-functionalized POSS derivative (POSSProDOT) as cross-linker. PEDOT copolymer films were electrochemically deposited with various concentrations of POSS-ProDOT. The optical, morphological and electrochemical properties of the copolymer films could be systematically tuned with the incorporation of POSS-ProDOT. Significantly enhanced electrochemical and mechanical stability of the copolymers were observed at intermediate levels of POSS-ProDOT content (3.1 wt%) via chronic stimulation tests. Surface functionalization of conducting polymer films provides a potential means for systematically tailoring their chemical and physical properties. We have synthesized, polymerized and characterized a dialkene

  5. Thin Film Polymer Composite Scintillators for Thermal Neutron Detection

    Directory of Open Access Journals (Sweden)

    Andrew N. Mabe

    2013-01-01

    Full Text Available Thin film polystyrene composite scintillators containing LiF6 and organic fluors have been fabricated and tested as thermal neutron detectors. Varying fluorescence emission intensities for different compositions are interpreted in terms of the Beer-Lambert law and indicate that the sensitivity of fluorescent sensors can be improved by incorporating transparent particles with refractive index different than that of the polymer matrix. Compositions and thicknesses were varied to optimize the fluorescence and thermal neutron response and to reduce gamma-ray sensitivity. Neutron detection efficiency and neutron/gamma-ray discrimination are reported herein as functions of composition and thickness. Gamma-ray sensitivity is affected largely by changing thickness and unaffected by the amount of LiF6 in the film. The best neutron/gamma-ray discrimination characteristics are obtained for film thicknesses in the range 25–150 μm.

  6. The local segmental dynamics of polymer thin films

    Science.gov (United States)

    Roland, C. M.; Casalini, Riccardo; Prevosto, Daniele; Labardi, Massimiliano; Zhu, Lei; Baer, Eric

    The local segmental dynamics of poly(methyl methacrylate) (PMMA) in multi-layered films with polycarbonate was investigated using dielectric spectroscopy. The segmental relaxation time decreased with layer thickness down to 4 nm. However, two measures of the cooperativity of the dynamics, the breadth of the relaxation dispersion and the dynamic correlation volume, were unaffected by the film thickness. This absence of an effect of geometric confinement on the cooperativity, even when the confinement length scale approaches the correlation length scale, requires an asymmetric correlation volume; i.e., correlating regions having a string-like nature. To further probe the effect of layering on the segmental dynamics, we measured the segmental dynamics of poly(vinylacetate) thin films in contact with variously an aluminum interface, an incompatible polymer, and air (free surface). From local dielectric relaxation measurements using an AFM tip, the dynamics were observed to be faster in all thin film configurations compared to the bulk. However, no differences were observed for the various interfaces; capping the thin films with a rigid material accelerated the segmental motions equivalently to that for an air interface. This insensitivity of the dynamics to the nature of the interface affords a means to engineer thin films while maintaining desired mechanical properties. Work at NRL supported by the Office of Naval Research.

  7. Capillary Instability in Nanoimprinted Polymer Films

    Energy Technology Data Exchange (ETDEWEB)

    Alvine, Kyle J.; Ding, Yifu; Douglas, Jack F.; Ro, Hyun W.; Okerberg, Brian C.; Karim, Alamgir; Soles, Christopher L.

    2009-07-01

    Capillary forces play an active role in defining the equilibrium structure of nanoscale structures. This effect can be especially pronounced in soft materials such as polymers near or above their glass transition temperature Tg where material flow is possible. In these situations, the effect of surface tension can produce varied and complex capillary instabilities, even in relatively simple geometries such as parallel line-space grating patterns. Here we investigate a novel capillary instability that arises in polystyrene line-space gratings with a residual layer connecting these structures (created by nanoimprint lithography) upon thermal annealing of these patterns. This novel instability is characterized by the development of lateral undulations of the lines that culminates in the local coalescence of adjacent imprinted lines. An exact analytic model of this undulatory instability is not possible, but we introduce a simple physical model for this lateral instability based on the driving force to reduce the surface energy, as in the well-known Rayleigh-Plateau instability which is likewise surface energy driven. Good agreement is obtained between this simplified model and our observations. Our insights into the nature of this instability have implications for controlling the thermal stability of nanoscale patterns made by nanoimprint lithography or other lithography techniques.

  8. Determination of macroscopic electro-mechanical characteristics of 1-3 piezoceramic/polymer composites by a concentric tube model

    DEFF Research Database (Denmark)

    Jensen, Henrik

    1991-01-01

    An axisymmetric concentric tube model of a piezoelectric rod and a concentric elastic tube is used to characterize 1-3 piezoelectric/elastic composites macroscopically. With average displacements of and total forces on the surfaces as the mechanical degrees of freedom, and with charge and potential...... at the ends of the rod as the electrical degrees of freedom, the relation between the electromechanical degrees of freedom is given in a matrix formulation. A recursive numerical scheme for combining the matrix for the tube and the piezoelectric rod into one for the composite piezoelectric rod is used...

  9. Structure and Morphology Control in Thin Films of Conjugated Polymers for an Improved Charge Transport

    OpenAIRE

    Haiyang Wang; Yaozhuo Xu; Xinhong Yu; Rubo Xing; Jiangang Liu; Yanchun Han

    2013-01-01

    The morphological and structural features of the conjugated polymer films play an important role in the charge transport and the final performance of organic optoelectronics devices [such as organic thin-film transistor (OTFT) and organic photovoltaic cell (OPV), etc.] in terms of crystallinity, packing of polymer chains and connection between crystal domains. This review will discuss how the conjugated polymer solidify into, for instance, thin-film structures, and how to control the molecula...

  10. Structure and Morphology Control in Thin Films of Conjugated Polymers for an Improved Charge Transport

    OpenAIRE

    Haiyang Wang; Yaozhuo Xu; Xinhong Yu; Rubo Xing; Jiangang Liu; Yanchun Han

    2013-01-01

    The morphological and structural features of the conjugated polymer films play an important role in the charge transport and the final performance of organic optoelectronics devices [such as organic thin-film transistor (OTFT) and organic photovoltaic cell (OPV), etc.] in terms of crystallinity, packing of polymer chains and connection between crystal domains. This review will discuss how the conjugated polymer solidify into, for instance, thin-film structures, and how to control the molecula...

  11. Tuning Morphologies of Langmuir Polymer Films Through Controlled Relaxations of Non-Equilibrium States.

    Science.gov (United States)

    Chandran, Sivasurender; Dold, Stefanie; Buvignier, Amaury; Krannig, Kai-Steffen; Schlaad, Helmut; Reiter, Günter; Reiter, Renate

    2015-06-16

    Langmuir polymers films (LPFs) frequently form nonequilibrium states which are manifested in a decay of the surface pressure with time when the system is allowed to relax. Monitoring and manipulating the temporal evolution of these relaxations experimentally helps to shed light on the associated molecular reorganization processes. We present a systematic study based on different compression protocols and show how these reorganization processes impact the morphology of LPFs of poly(γ-benzyl-L-glutamate)(PBLG), visualized by means of atomic force microscopy. Upon continuous compression, a fibrillar morphology was formed with a surface decorated by squeezed-out islands. By contrast, stepwise compression promoted the formation of a fibrillar network with a bimodal distribution of fibril diameters, caused by merging of fibrils. Finally, isobaric compression induced in-plane compaction of the monolayer. We correlate these morphological observations with the kinetics of the corresponding relaxations, described best by a sum of two exponential functions with different time scales representing two molecular processes. We discuss the observed kinetics and the resulting morphologies in the context of nucleation and growth, characteristic for first-order phase transitions. Our results demonstrate that the preparation conditions of LPFs have tremendous impact on ordering of the molecules and hence various macroscopic properties of such films.

  12. Relation Between Glass Transition Temperatures in Polymer Nanocomposites and Polymer Thin Films

    Science.gov (United States)

    Kropka, Jamie; Pryamitsyn, Victor; Ganesan, Venkat

    2009-03-01

    Motivated by recent experiments, we examine within a percolation model whether there is a quantitative equivalence in the glass transition temperatures of polymer thin films and polymer nanocomposites (PNCs). Our results indicate that while the qualitative behaviors of these systems are similar, a quantitative equivalence cannot be established in general. However, we propose a phenomenological scaling collapse of our results which suggests a simple framework by which the results of the thin films may be used to quantitatively predict the properties of PNCs. Sandia is a multi-program laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under Contract DE-AC04-94AL85000.

  13. Polarization Raman Microscopic Study of Molecular Alignment Behavior in Liquid Crystal/Polymer Composite Films

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro; Sato, Fumio

    2005-12-01

    We clarified that the molecular alignment of aggregated polymers is partially synchronized with liquid crystal (LC) director reorientation in an LC/polymer composite film. The molecular alignment behavior in composite films with LC- and polymer-rich regions formed by photopolymerization-induced phase separation was investigated using polarization Raman spectral microscopy. Raman scattering intensity induced by aligned side chains of polymers in the LC-rich region changed with LC director reorientation when voltage was applied to the composite film. It was confirmed for the first time that polymers capable of movement are formed in the LC-rich region.

  14. Evolution of non-equilibrium entanglement networks in spincast thin polymer films

    Science.gov (United States)

    Dalnoki-Veress, Kari; McGraw, Joshua; Fowler, Paul

    2012-02-01

    Measuring the rheology of non-equilibrium thin polymer films has received significant attention recently. Experiments are typically performed on thin polymer films that inherit their structure from spin coating. While the results of several rheological experiments paint a clear picture, details of molecular configurations in spincast polymer films are still unknown. Here we present the results of crazing measurements which demonstrate that the effective entanglement density of thin polymer films changes as a function of annealing toward a stable equilibrium value. The effective entanglement density plateaus with a time scale on the same order as the bulk reptation time.

  15. Surface analysis of the selective excimer laser patterning of a thin PEDOT:PSS film on flexible polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Schaubroeck, David, E-mail: David.Schaubroeck@elis.ugent.be [Center for Microsystems Technology (CMST), imec and Ghent University, Technologiepark 15, B-9052 Ghent (Belgium); De Smet, Jelle; Willems, Wouter [Center for Microsystems Technology (CMST), imec and Ghent University, Technologiepark 15, B-9052 Ghent (Belgium); Cools, Pieter; De Geyter, Nathalie; Morent, Rino [Research Unit Plasma Technology (RUPT), Department of Applied Physics, Faculty of Engineering, Ghent University, Sint-Pietersnieuwstraat 41, B-9000 Ghent (Belgium); De Smet, Herbert; Van Steenbeerge, Geert [Center for Microsystems Technology (CMST), imec and Ghent University, Technologiepark 15, B-9052 Ghent (Belgium)

    2016-07-15

    Highlights: • Laser patterning of thin film PEDOT:PSS on polymer foils is characterized in great detail. • PEDOT:PSS does not need to be fully removed to create electrically insulating patterns. • The underlying polymer foil influences the ablation behavior. - Abstract: Fast patterning of highly conductive polymers like PEDOT:PSS (poly (3,4-ethylene dioxythiophene): polystyrene sulfonate) with lasers can contribute to the development of industrial production of liquid crystal displays on polymer foils. In this article, the selective UV laser patterning of a PEDOT:PSS film on flexible polymer films is investigated. Based on their optical properties, three polymer films are investigated: polyethylene terephthalate (PET), polymethyl methacrylate (PMMA) and cellulose triacetate (TAC). Ablation parameters for a 110 nm PEDOT:PSS film on these polymer films are optimized. A detailed study of the crater depth, topography and surface composition are provided using optical profilometry, scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS), respectively. The electrical insulation of the lines is measured and correlated to the crater analyses for different laser settings. Finally, potential ablation parameters for each of the polymer films are derived.

  16. Selectively Patterning Polymer Opal Films via Microimprint Lithography.

    Science.gov (United States)

    Ding, Tao; Zhao, Qibin; Smoukov, Stoyan K; Baumberg, Jeremy J

    2014-11-01

    Large-scale structural color flexible coatings have been hard to create, and patterning color on them is key to many applications, including large-area strain sensors, wall-size displays, security devices, and smart fabrics. To achieve controlled tuning, a micro-imprinting technique is applied here to pattern both the surface morphology and the structural color of the polymer opal films (POFs). These POFs are made of 3D ordered arrays of hard spherical particles embedded inside soft shells. The soft outer shells cause the POFs to deform upon imprinting with a pre-patterned stamp, driving a flow of the soft polymer and a rearrangement of the hard spheres within the films. As a result, a patterned surface morphology is generated within the POFs and the structural colors are selectively modified within different regions. These changes are dependent on the pressure, temperature, and duration of imprinting, as well as the feature sizes in the stamps. Moreover, the pattern geometry and structural colors can then be further tuned by stretching. Micropattern color generation upon imprinting depends on control of colloidal transport in a polymer matrix under shear flow and brings many potential properties including stretchability and tunability, as well as being of fundamental interest.

  17. Polymer Brush Grafted Nanoparticles and Their Impact on the Morphology Evolution of Polymer Blend Films

    Science.gov (United States)

    Chung, Hyun-Joong; Ohno, Kohji; Composto, Russell

    2013-03-01

    We present an novel pathway to control the location of nanoparticles (NPs) in phase-separating polymer blend films containing poly(methyl methacrylate) (PMMA) and poly(styrene-ran-acrylonitrile) (SAN). Because hydrophobic polymer phases have a small interfacial energy, ~1 mJ/m2, subtle changes in the NP surface functionality can be used to guide NPs to either the interface between immiscible polymers or into one of the phases. Based on this idea, we designed a class of NPs grafted with PMMA brushes. These PMMA brushes were grown from the NP surface by atom transfer radical polymerization (ATRP), which results in chains terminated with chlorine atoms. The chain end can be substituted with protons (H) by dehalogenation. As a result, the NPs are strongly segregated at the interface when grafted PMMA chains are short (Mn =1.8K) and the end group is Cl, whereas NPs partition into PMMA-rich phase when chains are long (Mn =160K) and/or when chains are terminated with hydrogen. The Cl end groups and shorter chain length cause an increase in surface energy for the NPs. The increase in surface energy of short-chained NPs can be attributed to (i) an extended brush conformation (entropic) and/or (ii) a high density of ``unfavorable'' end groups (enthalpic). Finally, the impact of NPs on the morphological evolution of the polymer blend films will be discussed. Ref: H.-J.Chung et al., ACS Macro Lett. 1(1), 252-256 (2012).

  18. Piezoelectric characteristics of PZT thin films on polymer substrate

    Science.gov (United States)

    Kang, Min-Gyu; Do, Younh-Ho; Oh, Seung-Min; Rahayu, Rheza; Kim, Yiyein; Kang, Chong-Yun; Nahm, Sahn; Yoon, Seok-Jin

    2012-02-01

    The goal of piezoelectric energy harvesting is to improve the power efficiency of devices. One of the approaches for the improvement of power efficiency is to apply the large strain on the piezoelectric materials and then many scientists approached using thin films or nano-structured piezoelectric materials to obtain flexibility. However, the conventional thin film processes available for the fabrication of piezoelectric materials as PbZr0.52Ti0.48O3 (PZT) are not compatible with flexible electronics because they require high processing temperatures (>700^oC) to obtain piezoelectricity. Excimer laser annealing (ELA) is attractive heat process for the low-temperature crystallization, because of its material selectivity and short heating time. In this study, the amorphous PZT thin films were deposited on polymer substrate by rf-sputtering. To crystallize the amorphous films, the ELA was carried out with various conditions as function of the applied laser energy density, the number of pulse, and the repetition rate. To evaluate the piezoelectric characteristics, piezoelectric force microscopy (PFM) and electrometer are used. As a result, we obtained the crystallized PZT thin film on flexible substrate and obtained flexible piezoelectric energy harvester.

  19. Polymer-assisted deposition of metal-oxide films.

    Science.gov (United States)

    Jia, Q X; McCleskey, T M; Burrell, A K; Lin, Y; Collis, G E; Wang, H; Li, A D Q; Foltyn, S R

    2004-08-01

    Metal oxides are emerging as important materials for their versatile properties such as high-temperature superconductivity, ferroelectricity, ferromagnetism, piezoelectricity and semiconductivity. Metal-oxide films are conventionally grown by physical and chemical vapour deposition. However, the high cost of necessary equipment and restriction of coatings on a relatively small area have limited their potential applications. Chemical-solution depositions such as sol-gel are more cost-effective, but many metal oxides cannot be deposited and the control of stoichiometry is not always possible owing to differences in chemical reactivity among the metals. Here we report a novel process to grow metal-oxide films in large areas at low cost using polymer-assisted deposition (PAD), where the polymer controls the viscosity and binds metal ions, resulting in a homogeneous distribution of metal precursors in the solution and the formation of uniform metal-organic films. The latter feature makes it possible to grow simple and complex crack-free epitaxial metal-oxides.

  20. Deformation in Thin Glassy Polymer Films from Surface towards Interior

    Science.gov (United States)

    Chowdhury, Mithun; de Silva, Johann P.; Cross, Graham L. W.

    Polymer thin glassy films occupy an important place in last two decades of condensed matter research, concerning its surprising surface mobility and spatially dependent structural relaxation. However, ranges of cleverly designed indirect measurements on confined polymer glassy films already probed its mechanical properties; it is still a challenging task to directly probe such small confined volume through conventional mechanical testing. We have designed confined layer compression testing with a precisely designed and aligned flat probe during nanoindentation, which was further accompanied with atomic force microscopy. Due to natural confinement from the surrounding material, we show that a state of `uniaxial strain' is created beneath the probe under small axial strains. By this methodology we are able to directly probe uniaxial flows under both anelastic and plastic conditions while doing controlled creep studies at different positions in the film starting from surface towards interior. Depending on the extent of deformation, we found ranges of effects, such as densification, anelastic yield, and plastic yield. Enhanced creep rate upon deformation supports the idea of `deformation induced mobility'. Work performed at Trinity College Dublin.

  1. Dynamics of polymer film formation during spin coating

    Energy Technology Data Exchange (ETDEWEB)

    Mouhamad, Y.; Clarke, N.; Jones, R. A. L.; Geoghegan, M., E-mail: geoghegan@sheffield.ac.uk [Department of Physics and Astronomy, The University of Sheffield, Hicks Building, Hounsfield Road, Sheffield S3 7RH (United Kingdom); Mokarian-Tabari, P. [Materials Research Group, Department of Chemistry and the Tyndall National Institute, University College Cork, Cork (Ireland)

    2014-09-28

    Standard models explaining the spin coating of polymer solutions generally fail to describe the early stages of film formation, when hydrodynamic forces control the solution behavior. Using in situ light scattering alongside theoretical and semi-empirical models, it is shown that inertial forces (which initially cause a vertical gradient in the radial solvent velocity within the film) play a significant role in the rate of thinning of the solution. The development of thickness as a function of time of a solute-free liquid (toluene) and a blend of polystyrene and poly(methyl methacrylate) cast from toluene were fitted to different models as a function of toluene partial pressure. In the case of the formation of the polymer blend film, a concentration-dependent (Huggins) viscosity formula was used to account for changes in viscosity during spin coating. A semi-empirical model is introduced, which permits calculation of the solvent evaporation rate and the temporal evolution of the solute volume fraction and solution viscosity.

  2. Electric conductivity of polymer films filled with magnetic nanoparticles

    Science.gov (United States)

    Rumyantsev, B. M.; Bibikov, S. B.; Bychkova, A. V.; Leontiev, V. G.; Berendyaev, V. I.; Sorokina, O. N.; Kovarskii, A. L.

    2016-12-01

    The conductivity of polymer composites with magnetic nanoparticles (MNP) containing magnetite and other MNP (Ni, Cu-Ni) in the layers and planar cells with Al electrodes is studied. For soluble polymers (polyvinylpyrrolidone and polyvinyl alcohol) containing 1-10 wt % of magnetite MNP, a substantial effect of MNP on surface conductivity is detected over a wide range (from 10-10 to 10-3 Ω-1). It is shown that the addition of magnetite MNP not only results in a considerable change in cell conductivity, but also leads to its partially irreversible variation (by an order of magnitude or more) via minor modifications of the experimental conditions (temperature, electric field). For high-resistance samples with low probabilities of conducting chain formation, temperature current peaks are observed upon moderate heating (up to 350 K). These peaks are similar to the maxima observed upon polymer electret thermodischarges when the charges are captured by the deep centers associated with separate MNP or MNP aggregates. The type and position of the maxima are determined by the characteristics of the polymer matrix. For polyvinylpyrrolidone composites, the maxima are observed some time after heating (the echo effect). With composites based on solventborne polymers (polyalkanesterimides, soluble polyimide) and Ni, Cu-Ni MNP, no change in film conductivity measured electrophotographically is observed, due to the formation of a dielectric coating formed by polymer macromolecules adsorbed on the MNP surface. An explanation based on the possible formation of magnetic aggregates of magnetite MNP and conducting chains is proposed. Magnetic aggregation IPM is proposed as one way of controlling cell conductivity.

  3. Local Imaging of Optoelectronic Properties and Film Degradation in Polymer/Fullerene Solar Cells with Electrostatic Force Microscopy

    Science.gov (United States)

    Cox, Phillip Alexander

    photovoltaic materials as a testbed, we study macroscopic device degradation as a function of photooxidation for three different film morphologies. According to EQE measurements, we find that the stability of the macroscopic devices is very sensitive to processing conditions, with films processed with the solvent additive 1,8-diiodooctane being the most stable. At the microscopic level, we compare the evolution of cantilever power dissipation as a function of photochemical degradation for three different polymer/fullerene blend morphologies, and show that the evolution of local power dissipation correlates with device stability. Lastly, we show that cantilever power dissipation increases more rapidly over large fullerene aggregates than in well-mixed polymer/fullerene regions, suggesting that local photochemistry on the fullerene contributes strongly to the dissipation signal.

  4. PHOTOINDUCED HOLOGRAPHIC PHASE GRATINGS BURIED IN AZOBENZENE SIDE-CHAIN POLYMER FILMS WITH A CHIRAL GROUP

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    An optically active polymer (PM1) containing azobenzene moieties with a chiral group (s-2-methyl-butyl) was synthesized by homopolymerization of monomer, 4-[2-(methacryloyloxy)ethyloxy]-4'-(s-2-methyl-1-butyloxycarbonyl)azobenzene, using the free radical polymerization method. The polymer dissolved in tetrahydrofuran (THF) could be easily processed into high optical quality films. The optical anisotropy of the polymer films was investigated by polarizing optical microscopy (POM). The experimental results showed that irradiation with a circularly polarized beam could align the orientation of the molecules in the polymer films. Moreover, the holographic phase gratings of photo-induced polymer films were detected by atomic force microscopy (AFM) and POM. In comparison with polymer containing no chiral group, it was found from the preliminary measurement of the photo-induced holographic phase gratings that PM1 containing a chiral group could form holographic phase gratings buried in the films.

  5. Electroluminescence and photoluminescence of conjugated polymer films prepared by plasma enhanced chemical vapor deposition of naphthalene

    CERN Document Server

    Rajabi, Mojtaaba; Firouzjah, Marzieh Abbasi; Hosseini, Seyed Iman; Shokri, Babak

    2012-01-01

    Polymer light-emitting devices were fabricated utilizing plasma polymerized thin films as emissive layers. These conjugated polymer films were prepared by RF Plasma Enhanced Chemical Vapor Deposition (PECVD) using naphthalene as monomer. The effect of different applied powers on the chemical structure and optical properties of the conjugated polymers was investigated. The fabricated devices with structure of ITO/PEDOT:PSS/ plasma polymerized Naphthalene/Alq3/Al showed broadband Electroluminescence (EL) emission peaks with center at 535-550 nm. Using different structural and optical tests, connection between polymers chemical structure and optical properties under different plasma powers has been studied. Fourier transform infrared (FTIR) and Raman spectroscopies confirmed that a conjugated polymer film with a 3-D cross-linked network was developed. By increasing the power, products tended to form as highly cross-linked polymer films. Photoluminescence (PL) spectra of plasma polymers showed different excimerc ...

  6. Structure and Morphology Control in Thin Films of Conjugated Polymers for an Improved Charge Transport

    Directory of Open Access Journals (Sweden)

    Haiyang Wang

    2013-11-01

    Full Text Available The morphological and structural features of the conjugated polymer films play an important role in the charge transport and the final performance of organic optoelectronics devices [such as organic thin-film transistor (OTFT and organic photovoltaic cell (OPV, etc.] in terms of crystallinity, packing of polymer chains and connection between crystal domains. This review will discuss how the conjugated polymer solidify into, for instance, thin-film structures, and how to control the molecular arrangement of such functional polymer architectures by controlling the polymer chain rigidity, polymer solution aggregation, suitable processing procedures, etc. These basic elements in intrinsic properties and processing strategy described here would be helpful to understand the correlation between morphology and charge transport properties and guide the preparation of efficient functional conjugated polymer films correspondingly.

  7. The scanning probe microscopy study of thin polymer films

    CERN Document Server

    Harron, H R

    1995-01-01

    spherulites fibrils was influenced by the chemical nature of the solvent Results reported here confirm that the fibril structure and spherulite size was significantly affected by the chemical nature of the plasticizing solvent. Detailed observations of the spherulites are included herein. A tapping mode AFM was used in conjunction with the usual contact mode AFM to image the fine spherulitic lamellae structure. It was found that the AFM operated in the tapping mode was less destructive than when operated in the contact mode and gave higher resolution images of the lamellae structure. The lamellae were found to be structurally very similar to the features observed in the study using STM indicating that under certain circumstances, the STM was less destructive over the 'insulating' polymer than the contact mode AFM. technique. Furthermore, images of the crystalline film contained elongated units that were attributed to the lamellae formations that form the basic building blocks of polymer spherulites. The study...

  8. π-Donors microstructuring on surface of polymer film by their noncovalent interactions with iodine

    Energy Technology Data Exchange (ETDEWEB)

    Traven, Valerii F., E-mail: valerii.traven@gmail.com [Mendeleev University of Chemical Technology, Moscow 125047, Miusskaya sq., 9 (Russian Federation); Ivanov, Ivan V.; Dolotov, Sergei M. [Mendeleev University of Chemical Technology, Moscow 125047, Miusskaya sq., 9 (Russian Federation); Veciana, Jaume Miro; Lebedev, Victor S. [Institut de Ciencia de Materials de Barcelona–CSIC, Campus de la UAB, 08193, Bellaterra (Spain); Shulga, Yurii M.; Khasanov, Salavat S. [Institute of Problems of Chemical Physics, Russian Academy of Sciences, Acad. N.N. Semenov Prosp., 1, Chernogolovka, 142432 (Russian Federation); Medvedev, Michael G. [A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow 119991, Vavilova str., 28 (Russian Federation); Laukhina, Elena E. [The Biomedical Research Networking Center in Bioengineering, Biomaterials and Nanomedicine, ICMAB-CSIC, Bellaterra, 08193 (Spain)

    2015-06-15

    Noncovalent (charge transfer) interaction between perylene and iodine in polycarbonate film provides formation of microstructured perylene layer on the polymer surface upon exposure of polymer film which contains dissolved perylene to solvent + iodine vapors. The prepared bilayer film possesses a sensing effect to iodine vapors which can be observed by both fluorescence and electrical conductivity changes. Similar bilayer films have been prepared also with anthracene and phenothiazine as π-donors with use of different polymer matrixes. Interaction of iodine with polycyclic aromatic hydrocarbons (PAH) has also been studied by the M06-2x DFT calculations for better understanding of phenomenon of π-donors microstructuring on surface of polymer film. - Highlights: • Preparation of bilayer polymer films with π-donors on surface for the first time. • π-Donor phase purity is confirmed by XRD, IR spectroscopy, SEM. • Perylene bilayer polymer films possess fluorescence. • Perylene bilayer polymer films loss fluorescence under iodine vapors. • Perylene bilayer polymer films possess electrical conductivity when treated by iodine vapors.

  9. Cellular Automata Simulations of Thermal and Electrical Transport Properties of Thin-Film Polymer/CNTs Nanocomposites

    Science.gov (United States)

    Casey, Alex; Iannacchione, Germano; Georgiev, Georgi; Cebe, Peggy

    2014-03-01

    A computational algorithm has been developed to simulate the transport properties of oriented and un-oriented thin film nanocomposites of isotactic Polypropylene (iPP) and carbon nanotubes (CNT) with increasing CNT concentration. Our goal is to be able to design materials with optimal properties using simulations. We use cellular automata approach in Matlab simulation environment. The percolation threshold is reproduced in the simulations, matching experimental data. Upon percolation, the thermal transport in the films increases sharply, more so for the electrical than for the thermal conductivity, due to the larger difference in the electric conductivities of the CNTs and the polymer. To verify the simulation, the thin-film samples were sheared in the melt at 200 C at 1 Hz in a Linkan microscope shearing hot stage. The thermal and electrical conductivity measurements were performed on the same cell arrangement with the transport perpendicular to the thin-film plane using a DC method. The thermal and electrical conductivity are higher for the un-sheared as compared to the sheared samples with stronger temperature dependence for the latter as compared to the former. Our cellular automata simulations provide information about the microstructure-macroscopic property relation in the thin film nanocomposites and can be extended to simulations of other important materials.

  10. A study of the initial film growth of PEG-like plasma polymer films via XPS and NEXAFS

    Energy Technology Data Exchange (ETDEWEB)

    Li, Yali [CSIRO Materials Science and Engineering, Clayton South, VIC 3169 (Australia); Department of Materials Engineering, Monash University, VIC 3800 (Australia); Muir, Benjamin W., E-mail: ben.muir@csiro.au [CSIRO Materials Science and Engineering, Clayton South, VIC 3169 (Australia); Easton, Christopher D. [CSIRO Materials Science and Engineering, Clayton South, VIC 3169 (Australia); Thomsen, Lars [Australian Synchrotron, Clayton, VIC 3168 (Australia); Nisbet, David R. [Research School of Engineering, College of Engineering and Computer Science, The Australian National University, Acton, ACT 0200 (Australia); Forsythe, John S., E-mail: john.forsythe@monash.edu [Department of Materials Engineering, Monash University, VIC 3800 (Australia)

    2014-01-01

    The chemistry of substrate–film interface (underside) of di(ethylene glycol) dimethyl ether plasma polymer (DGpp) films has been studied directly and compared to the top layer of the film (topside). By depositing the plasma polymer films onto indium tin oxide (ITO) glass, the films were easily delaminated from the substrate. The top- and underside of the films were examined by X-ray photoelectron spectroscopy (XPS) and near edge X-ray absorption fine structure (NEXAFS) spectroscopy. It was found that a rapid increase in pressure during plasma polymerization results in steep chemical gradients in the films, while small pressure changes do not lead to chemical gradient formation. These observations validate the findings of previous neutron reflectometry modeling studies of this class of plasma polymer thin film. In addition, subtle variations in plasma polymer film chemistry were observed between different substrates they were deposited onto. This approach will allow additional studies on the mechanisms of early plasma polymer thin film formation with various monomers.

  11. High temperature polymer dielectric film-wire insulation

    Science.gov (United States)

    Nairus, John G.

    1994-01-01

    The highlights of the program are outlined including two major accomplishments. TRW identified and demonstrated the potential of two aromatic/heterocyclic polymers to have an outstanding and superior combination of electrical, thermal, and chemical resistance properties versus state-of-the-art Kapton for spacecraft and/or aircraft dielectric insulation applications. (Supporting data is provided in tables.) Feasibility was demonstrated for supporting/enabling technologies such as ceramic coatings, continuous film casting, and conductor wire wrapping, which are designed to accelerate qualification and deployment of the new wire insulation materials for USAF systems applications during the mid- to late-1990's.

  12. Enhanced biocompatibility of PDMS (polydimethylsiloxane) polymer films by ion irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Ionescu, M., E-mail: Mihail.Ionescu@ansto.gov.au [Australian Nuclear Science and Technology Organization, Sydney (Australia); Winton, B.; Wexler, D. [Faculty of Engineering, University of Wollongong, Wollongong (Australia); Siegele, R.; Deslantes, A.; Stelcer, E.; Atanacio, A.; Cohen, D.D. [Australian Nuclear Science and Technology Organization, Sydney (Australia)

    2012-02-15

    PDMS films several microns thick deposited on polished Si wafers were irradiated with Mg, Ta, and Fe in the low energy range of 40 keV to 200 keV, and for doses of 10{sup 16}-10{sup 18} ions/cm{sup 2}. After irradiation the films surface is self-organised into 3D coherent and semi-coherent domains. As a consequence of the surface irradiation conditions and the surface boundary conditions, some domains are highly ordered in the form of parallel waves of approximately 1 {mu}m in height, or the result can be semi-ordered regions or disordered regions. In addition, the surface energy of the irradiated polymer is increasing, as reflected in the decrease in its surface hydrophobicity, which is beneficial for cell adhesion. The irradiated samples were tested in vivo, and the results show an increase in viable cell count of up to 650%.

  13. Photochromism and diffraction grating in cyanoazobenzene polymer films

    Science.gov (United States)

    Serwadczak, M.; Wübbenhorst, M.; Kucharski, S.

    2006-08-01

    Two series of photochromic copolymathacrylates containing cyanoazobenzene chromophores as side chains were described. The series with shorter ethylene spacer between mesogen and main polymethacrylate chain was amorphous, whereas the second one with longer ethoxyethylene spacer was liquid crystalline forming smectic C mesophase above Tg. The materials were deposited on glass substrates via spin coating and casting technique to provide thin transparent films. The reversible change of refractive index of the films on illumination with white light was determined by ellipsometry. The difference of real part of the refractive index of the sample was in the range 0.0067-0.0210 depending on the polymer. Formation of diffraction grating was achieved by two beam coupling arrangement using a 532 nm laser diode . The diffraction efficiency for the first order diffraction was in the range of 1.5-2.1% for the homopolymers.

  14. Soap opera : polymer-surfactant interactions on thin film surfaces /

    Energy Technology Data Exchange (ETDEWEB)

    Ozer, B. H. (Byram H.); Johal, M. S. (Malkiat S.); Wang, H. L. (Hsing-Lin); Robinson, J. M. (Jeanne M.)

    2001-01-01

    Surfactants are macromolecules with unique properties. They commonly contain a polar head group with a nonpolar hydrocarbon chain. These properties allow surfactants to solubilize greases and other nonpolar molecules. One particular way that this is accomplished is through the formation of micelles. Micelles are formed at the critical micelle concentration (cmc), which varies depending upon the nature of the surfactant and also the media in which the surfactant resides. These micelles can take a variety of shapes, but are generally characterized by surrounding the grease with the nonpolar hydrocarbon chains, exposing only the polarized head groups to the media, usually water. This property of easy solubilization has made surfactants a very attractive industrial agent, They are used most conventionally as industrial cleaning agents and detergents. However, they also have lesser-known applications in conjunction with polymers and other macromolecular mixtures, often creating a system with novel properties, such as increased solubilization and smoother mixture consistency. A recently developed field has investigated the self-assembly of polymers and polyelectrolytes onto thin film surfaces. There are many reasons for studying this process, such as for second harmonic generation purposes and bioassays. In this study, the interaction between the anionic polyelectrolyte poly[1-[4-(3-carboxy-4-hydroxyphenylazo)benzenesulfonamido]-1,2-ethanediyl, sodium salt] (PAZO) and two surfactants of opposite charge, Sodium Dodecyl Sulfate (SDS) and Dodecyl Trimethyl Ammonium Bromide (DTAB), in their assembly onto thin film surfaces was investigated. The kinetics of adsorbance onto the thin films was examined, followed by construction of 10-bilayer films using an alternating layer of the cationic polyelectrolyte poly(ethylenimine) (PEI) to provide the electrostatic means for the PAZO/surfactant combination to assemble onto the thin film. The kinetics of adsorption is being

  15. Wrinkling, folding, and snapping instabilities in polymer films

    Science.gov (United States)

    Holmes, Douglas Peter

    This work focuses on understanding deformation mechanisms and responsiveness associated with the wrinkling, folding, and snapping of thin polymer films. We demonstrated the use of elastic instabilities in confined regimes, such as the crumpling and snapping of surface attached sheets. We gained fundatmental insight into a thin film's ability to localize strain. By taking advantage of geometric strain localization we were able to develop new strategies for responsive surfaces that will have a broad impact on adhesive, optical, and patterning applications. Using the rapid closure of the Venus flytrap's leaflets as dictated by the onset of a snap instability as motivation, we created surfaces with patterned structures to transition through a snap instability at a prescribed stress state. This mechanism causes surface topography to change over large lateral length scales and very short timescales. Changes in the stress state can be related to triggers such as chemical swelling, light-induced architecture transitions, mechanical pressure, or voltage. The primary advantages of the snap transition are that the magnitude of change, the rate of change, and the sensitivity to change can be dictated by a balance of materials properties and geometry. The patterned structures that exhibit these dynamics are elastomeric shells that geometrically localize strain and can snap between concave and convex curvatures. We have demonstrated the control of the microlens shell geometry and that the transition time follows scaling relationships presented for the Venus flytrap. Furthermore, the microlens arrays have been demonstrated as surfaces that can alter wettability. Using a similar novel processing technique, microarrays of freestanding elastomeric plates were placed in equibiaxial compression to fabricate crumpled morphologies with strain localized regions that are difficult to attain through traditional patterning techniques. The microstructures that form can be initially described

  16. Silicon nanowires in polymer nanocomposites for photovoltaic hybrid thin films

    Energy Technology Data Exchange (ETDEWEB)

    Ben Dkhil, S., E-mail: sadok.bendekhil@gmail.com [Laboratoire Physique des Materiaux, Structures et Proprietes Groupe Physique des Composants et Dispositifs Nanometriques, 7021 Jarzouna, Bizerte (Tunisia); Ingenierie des Materiaux Polymeres, IMP, UMR CNRS 5223, Universite Claude Bernard - Lyon 1, 15, boulevard Latarjet, 69622 Villeurbanne (France); Bourguiga, R. [Laboratoire Physique des Materiaux, Structures et Proprietes Groupe Physique des Composants et Dispositifs Nanometriques, 7021 Jarzouna, Bizerte (Tunisia); Davenas, J. [Ingenierie des Materiaux Polymeres, IMP, UMR CNRS 5223, Universite Claude Bernard - Lyon 1, 15, boulevard Latarjet, 69622 Villeurbanne (France); Cornu, D. [Institut Europeen des Membranes, UMR CNRS 5635, Ecole Nationale superieure de Chimie, Universite de Montpellier, 1919 route de Mende, F34000 Montpellier (France)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer Hybrid solar cells based on blends of poly(N-vinylcarbazole) and silicon nanowires have been fabricated. Black-Right-Pointing-Pointer We have investigated the charge transfer between PVK and SiNWs by the way of the quenching of the PVK photoluminescence. Black-Right-Pointing-Pointer The relation between the morphology of the composite thin films and the charge transfer between SiNWs and PVK has been examined. Black-Right-Pointing-Pointer We have investigated the effects of SiNWs concentration on the photovoltaic characteristics leading to the optimization of a critical SiNWs concentration. - Abstract: Hybrid thin films combining the high optical absorption of a semiconducting polymer film and the electronic properties of silicon fillers have been investigated in the perspective of the development of low cost solar cells. Bulk heterojunction photovoltaic materials based on blends of a semiconductor polymer poly(N-vinylcarbazole) (PVK) as electron donor and silicon nanowires (SiNWs) as electron acceptor have been studied. Composite PVK/SiNWs films were cast from a common solvent mixture. UV-visible spectrometry and photoluminescence of the composites have been studied as a function of the SiNWs concentration. Photoluminescence spectroscopy (PL) shows the existence of a critical SiNWs concentration of about 10 wt % for PL quenching corresponding to the most efficient charge pair separation. The photovoltaic (PV) effect has been studied under illumination. The optimum open-circuit voltage V{sub oc} and short-circuit current density J{sub sc} are obtained for 10 wt % SiNWs whereas a degradation of these parameters is observed at higher SiNWs concentrations. These results are correlated to the formation of aggregates in the composite leading to recombination of the photogenerated charge pairs competing with the dissociation mechanism.

  17. Modification of plasma polymer films by ion implantation

    Directory of Open Access Journals (Sweden)

    Santos Deborah Cristina Ribeiro dos

    2004-01-01

    Full Text Available In this work, thin polymer films were prepared from acetylene and argon radiofrequency (13.56 MHz, 80 W glow discharges. Post-deposition treatment was performed by plasma immersion ion implantation in nitrogen or helium glow discharges (13.56 MHz, 70 W. In these cases, samples were biased with 25 kV negative pulses. Exposure time to the bombardment plasma, t, ranged from 900 to 7200 s. Chemical composition of the film surfaces was investigated by X-ray Photoelectron Spectroscopy and the resistance to oxidation by the etching process, in reactive oxygen plasmas. Oxygen and nitrogen were detected in all the samples. While the concentration of the former continuously changed with t, that of N kept practically constant in small proportions. The film is predominantly formed by sp² states, but the proportion of sp³ hybridization slightly increased with t. The etching rate dropped under certain conditions of nitrogen bombardment whereas helium implantation has not significantly improved it. These results are ascribed to the crosslinking degree of the polymeric chains, ruled by the total amount of energy delivered to the film.

  18. Hybrid Thin Films Based Upon Polyoxometalates-Polymer Assembly

    Science.gov (United States)

    Qi, Na; Jing, Benxin; Zhu, Yingxi

    2014-03-01

    Block copolymers (BCPs) and polyoxometalates (POMs) have been used individually as building blocks for design and synthesis of novel functional materials. POM nanoclusters, the assemblies of transition metal oxides with well-defined atomic coordination structure, have been recently explored as novel nanomaterials... for catalysis, semiconductors, and even anti-cancer treatment due to their unique chemical, optical and electrical characteristics. We have explored the blending of inorganic POM nanocluster with BCPs into hierarchaically structured inorganic-organic hybrid nanocomposites. Using polystyrene-b-poly(ethylene oxide) (PS-b-PEO) thin films as the template, we have observed that the spatial organization of BCP thin films is modified by molybdenum based POM nanocluster to form 2D in-plane hexagonal ordered or 3D ordered network of POM-BCP assemblies, depending on the concentration ratio of POM to PS-b-PEO. The dielectric properties of such hybrid thin films can be enhanced by embedded POMs but show a strong dependence on the supramolecular structures of POM-polymer complexes. The assembly of nanoclusters in BCP-templated thin films could pave a new path to design new hybrid nanocomposites with uniquely combined functionality and material properties.

  19. Numerical simulations of electrohydrodynamic evolution of thin polymer films

    Science.gov (United States)

    Borglum, Joshua Christopher

    Recently developed needleless electrospinning and electrolithography are two successful techniques that have been utilized extensively for low-cost, scalable, and continuous nano-fabrication. Rational understanding of the electrohydrodynamic principles underneath these nano-manufacturing methods is crucial to fabrication of continuous nanofibers and patterned thin films. This research project is to formulate robust, high-efficiency finite-difference Fourier spectral methods to simulate the electrohydrodynamic evolution of thin polymer films. Two thin-film models were considered and refined. The first was based on reduced lubrication theory; the second further took into account the effect of solvent drying and dewetting of the substrate. Fast Fourier Transform (FFT) based spectral method was integrated into the finite-difference algorithms for fast, accurately solving the governing nonlinear partial differential equations. The present methods have been used to examine the dependencies of the evolving surface features of the thin films upon the model parameters. The present study can be used for fast, controllable nanofabrication.

  20. Solid mesostructured polymer-surfactant films at the air-liquid interface.

    Science.gov (United States)

    Pegg, Jonathan C; Eastoe, Julian

    2015-08-01

    Pioneering work by Edler et al. has spawned a new sub-set of mesostructured materials. These are solid, self-supporting films comprising surfactant micelles encased within polymer hydrogel; composite polymer-surfactant films can be grown spontaneously at the air-liquid interface and have defined and controllable mesostructures. Addition of siliconalkoxide to polymer-surfactant mixtures allows for the growth of mesostructured hybrid polymer-surfactant silica films that retain film geometry after calcinations and exhibit superior mechanical properties to typically brittle inorganic films. Growing films at the air-liquid interface provides a rapid and simple means to prepare ordered solid inorganic films, and to date the only method for generating mesostructured films thick enough (up to several hundred microns) to be removed from the interface. Applications of these films could range from catalysis to encapsulation of hydrophobic species and drug delivery. Film properties and mesostructures are sensitive to surfactant structure, polymer properties and polymer-surfactant phase behaviour: herein it will be shown how film mesostructure can be tailored by directing these parameters, and some interesting analogies will be drawn with more familiar mesostructured silica materials.

  1. Prism coupling technique investigation of elasto-optical properties of thin polymer films

    NARCIS (Netherlands)

    Ay, Feridun; Kocabas, Askin; Kocabas, Coskun; Aydinli, Atilla; Agan, Sedat

    2004-01-01

    The use of thin polymer films in optical planar integrated optical circuits is rapidly increasing. Much interest, therefore, has been devoted to characterizing the optical and mechanical properties of thin polymer films. This study focuses on measuring the elasto-optical properties of three differen

  2. Preparation of Composite Films of a Conjugated Polymer and C60NWs and Their Photovoltaic Application

    OpenAIRE

    Takatsugu Wakahara; Kun’ichi Miyazawa; Osamu Ito; Nobutaka Tanigaki

    2016-01-01

    Composite films of conjugated polymers, such as poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) and poly(3-hexylthiophene) (P3HT), with C60 nanowhiskers (C60NWs) were prepared. The photoluminescence originating from the conjugated MDMO-PPV polymers was effectively quenched in the composite film, indicating a strong interaction between the conjugated polymer and C60NWs. The photovoltaic devices were fabricated using C60NW (conjugated polymer) composite films, result...

  3. Preparation of Composite Films of a Conjugated Polymer and C60NWs and Their Photovoltaic Application

    OpenAIRE

    Takatsugu Wakahara; Kun’ichi Miyazawa; Osamu Ito; Nobutaka Tanigaki

    2016-01-01

    Composite films of conjugated polymers, such as poly[2-methoxy-5-(3′,7′-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) and poly(3-hexylthiophene) (P3HT), with C60 nanowhiskers (C60NWs) were prepared. The photoluminescence originating from the conjugated MDMO-PPV polymers was effectively quenched in the composite film, indicating a strong interaction between the conjugated polymer and C60NWs. The photovoltaic devices were fabricated using C60NW (conjugated polymer) composite films, result...

  4. Impact of polymer film thickness and cavity size on polymer flow during embossing : towards process design rules for nanoimprint lithography.

    Energy Technology Data Exchange (ETDEWEB)

    Schunk, Peter Randall; King, William P. (Georgia Institute of Technology, Atlanta, GA); Sun, Amy Cha-Tien; Rowland, Harry D. (Georgia Institute of Technology, Atlanta, GA)

    2006-08-01

    This paper presents continuum simulations of polymer flow during nanoimprint lithography (NIL). The simulations capture the underlying physics of polymer flow from the nanometer to millimeter length scale and examine geometry and thermophysical process quantities affecting cavity filling. Variations in embossing tool geometry and polymer film thickness during viscous flow distinguish different flow driving mechanisms. Three parameters can predict polymer deformation mode: cavity width to polymer thickness ratio, polymer supply ratio, and Capillary number. The ratio of cavity width to initial polymer film thickness determines vertically or laterally dominant deformation. The ratio of indenter width to residual film thickness measures polymer supply beneath the indenter which determines Stokes or squeeze flow. The local geometry ratios can predict a fill time based on laminar flow between plates, Stokes flow, or squeeze flow. Characteristic NIL capillary number based on geometry-dependent fill time distinguishes between capillary or viscous driven flows. The three parameters predict filling modes observed in published studies of NIL deformation over nanometer to millimeter length scales. The work seeks to establish process design rules for NIL and to provide tools for the rational design of NIL master templates, resist polymers, and process parameters.

  5. Coupled effects of substrate adhesion and intermolecular forces on polymer thin film glass-transition behavior.

    Science.gov (United States)

    Xia, Wenjie; Keten, Sinan

    2013-10-15

    Intermolecular noncovalent forces between polymer chains influence the mobility and glass-transition temperature (Tg), where weaker interchain interactions, all else being the same, typically results in lower bulk polymer Tg. Using molecular dynamics simulations, here we show that this relation can become invalid for supported ultrathin films when the substrate-polymer interaction is extremely strong and the polymer-polymer interactions are much weaker. This contrasting trend is found to be due to a more pronounced substrate-induced appreciation of the film Tg for polymers with weaker intermolecular interactions and low bulk Tg. We show that optimizing this coupling between substrate adhesion and bulk Tg maximizes thin film Tg, paving the way for tuning film properties through interface nanoengineering.

  6. Measurement of in-plane thermal conductivity in polymer films

    National Research Council Canada - National Science Library

    Wei, Qingshuo; Uehara, Chinatsu; Mukaida, Masakazu; Kirihara, Kazuhiro; Ishida, Takao

    2016-01-01

    .... We evaluated thermal conductivities and anisotropic ratios for various types of samples including insulating polymers, undoped semiconducting polymers, doped conducting polymers, and one-dimensional...

  7. Modeling thin-film piezoelectric polymer ultrasonic sensors

    Science.gov (United States)

    González, M. G.; Sorichetti, P. A.; Santiago, G. D.

    2014-11-01

    This paper presents a model suitable to design and characterize broadband thin film sensors based on piezoelectric polymers. The aim is to describe adequately the sensor behavior, with a reasonable number of parameters and based on well-known physical equations. The mechanical variables are described by an acoustic transmission line. The electrical behavior is described by the quasi-static approximation, given the large difference between the velocities of propagation of the electrical and mechanical disturbances. The line parameters include the effects of the elastic and electrical properties of the material. The model was validated with measurements of a poly(vinylidene flouride) sensor designed for short-pulse detection. The model variables were calculated from the properties of the polymer at frequencies between 100 Hz and 30 MHz and at temperatures between 283 K and 313 K, a relevant range for applications in biology and medicine. The simulations agree very well with the experimental data, predicting satisfactorily the influence of temperature and the dielectric properties of the polymer on the behavior of the sensor. Conversely, the model allowed the calculation of the material dielectric properties from the measured response of the sensor, with good agreement with the published values.

  8. Simulation of bipolar charge transport in nanocomposite polymer films

    Science.gov (United States)

    Lean, Meng H.; Chu, Wei-Ping L.

    2015-03-01

    This paper describes 3D particle-in-cell simulation of bipolar charge injection and transport through nanocomposite film comprised of ferroelectric ceramic nanofillers in an amorphous polymer matrix. The classical electrical double layer (EDL) model for a monopolar core is extended (eEDL) to represent the nanofiller by replacing it with a dipolar core. Charge injection at the electrodes assumes metal-polymer Schottky emission at low to moderate fields and Fowler-Nordheim tunneling at high fields. Injected particles migrate via field-dependent Poole-Frenkel mobility and recombine with Monte Carlo selection. The simulation algorithm uses a boundary integral equation method for solution of the Poisson equation coupled with a second-order predictor-corrector scheme for robust time integration of the equations of motion. The stability criterion of the explicit algorithm conforms to the Courant-Friedrichs-Levy limit assuring robust and rapid convergence. The model is capable of simulating a wide dynamic range spanning leakage current to pre-breakdown. Simulation results for BaTiO3 nanofiller in amorphous polymer matrix indicate that charge transport behavior depend on nanoparticle polarization with anti-parallel orientation showing the highest leakage conduction and therefore lowest level of charge trapping in the interaction zone. Charge recombination is also highest, at the cost of reduced leakage conduction charge. The eEDL model predicts the meandering pathways of charge particle trajectories.

  9. Electrochemical route to fabricate film-like conjugated microporous polymers and application for organic electronics.

    Science.gov (United States)

    Gu, Cheng; Chen, Youchun; Zhang, Zhongbo; Xue, Shanfeng; Sun, Shuheng; Zhang, Kai; Zhong, Chengmei; Zhang, Huanhuan; Pan, Yuyu; Lv, Ying; Yang, Yanqin; Li, Fenghong; Zhang, Suobo; Huang, Fei; Ma, Yuguang

    2013-07-05

    Film-like conjugated microporous polymers (CMPs) are fabricated by the novel strategy of carbazole-based electropolymerization. The CMP film storing a mass of counterions acting as an anode interlayer provides a significant power-conversion efficiency of 7.56% in polymer solar cells and 20.7 cd A(-1) in polymer light-emitting diodes, demonstrating its universality and potential as an electrode interlayer in organic electronics.

  10. Direct induction of molecular alignment in liquid crystal polymer network film by photopolymerization

    Science.gov (United States)

    Hisano, K.; Aizawa, M.; Ishizu, M.; Kurata, Y.; Shishido, A.

    2016-09-01

    Liquid crystal (LC) is the promising material for the fabrication of high-performance soft, flexible devices. The fascinating and useful properties arise from their cooperative effect that inherently allows the macroscopic integration and control of molecular alignment through various external stimuli. To date, light-matter interaction is the most attractive stimuli and researchers developed photoalignment through photochemical or photophysical reactions triggered by linearly polarized light. Here we show the new choice based on molecular diffusion by photopolymerization. We found that photopolymerization of a LC monomer and a crosslinker through a photomask enables to direct molecular alignment in the resultant LC polymer network film. The key generating the molecular alignment is molecular diffusion due to the difference of chemical potentials between irradiated and unirradiated regions. This concept is applicable to various shapes of photomask and two-dimensional molecular alignments can be fabricated depending on the spatial design of photomask. By virtue of the inherent versatility of molecular diffusion in materials, the process would shed light on the fabrication of various high-performance flexible materials with molecular alignment having controlled patterns.

  11. Singlet Exciton Lifetimes in Conjugated Polymer Films for Organic Solar Cells

    KAUST Repository

    Dimitrov, Stoichko

    2016-01-13

    The lifetime of singlet excitons in conjugated polymer films is a key factor taken into account during organic solar cell device optimization. It determines the singlet exciton diffusion lengths in polymer films and has a direct impact on the photocurrent generation by organic solar cell devices. However, very little is known about the material properties controlling the lifetimes of singlet excitons, with most of our knowledge originating from studies of small organic molecules. Herein, we provide a brief summary of the nature of the excited states in conjugated polymer films and then present an analysis of the singlet exciton lifetimes of 16 semiconducting polymers. The exciton lifetimes of seven of the studied polymers were measured using ultrafast transient absorption spectroscopy and compared to the lifetimes of seven of the most common photoactive polymers found in the literature. A plot of the logarithm of the rate of exciton decay vs. the polymer optical bandgap reveals a medium correlation between lifetime and bandgap, thus suggesting that the Energy Gap Law may be valid for these systems. This therefore suggests that small bandgap polymers can suffer from short exciton lifetimes, which may limit their performance in organic solar cell devices. In addition, the impact of film crystallinity on the exciton lifetime was assessed for a small bandgap diketopyrrolopyrrole co-polymer. It is observed that the increase of polymer film crystallinity leads to reduction in exciton lifetime and optical bandgap again in agreement with the Energy Gap Law.

  12. Singlet Exciton Lifetimes in Conjugated Polymer Films for Organic Solar Cells

    Directory of Open Access Journals (Sweden)

    Stoichko D. Dimitrov

    2016-01-01

    Full Text Available The lifetime of singlet excitons in conjugated polymer films is a key factor taken into account during organic solar cell device optimization. It determines the singlet exciton diffusion lengths in polymer films and has a direct impact on the photocurrent generation by organic solar cell devices. However, very little is known about the material properties controlling the lifetimes of singlet excitons, with most of our knowledge originating from studies of small organic molecules. Herein, we provide a brief summary of the nature of the excited states in conjugated polymer films and then present an analysis of the singlet exciton lifetimes of 16 semiconducting polymers. The exciton lifetimes of seven of the studied polymers were measured using ultrafast transient absorption spectroscopy and compared to the lifetimes of seven of the most common photoactive polymers found in the literature. A plot of the logarithm of the rate of exciton decay vs. the polymer optical bandgap reveals a medium correlation between lifetime and bandgap, thus suggesting that the Energy Gap Law may be valid for these systems. This therefore suggests that small bandgap polymers can suffer from short exciton lifetimes, which may limit their performance in organic solar cell devices. In addition, the impact of film crystallinity on the exciton lifetime was assessed for a small bandgap diketopyrrolopyrrole co-polymer. It is observed that the increase of polymer film crystallinity leads to reduction in exciton lifetime and optical bandgap again in agreement with the Energy Gap Law.

  13. Electric Transport Phenomena of Nanocomposite Organic Polymer Thin Films

    Science.gov (United States)

    Jira, Nicholas C.; Sabirianov, Ildar; Ilie, Carolina C.

    We discuss herein the nanocomposite organic thin film diodes for the use of plasmonic solar cells. This experimental work follows the theoretical calculations done for plasmonic solar cells using the MNPBEM toolbox for MatLab. These calculations include dispersion curves and amount of light scattering cross sections for different metallic nanoparticles. This study gives us clear ideas on what to expect from different metals, allowing us to make the best choice on what to use to obtain the best results. One specific technique for light trapping in thin films solar cells utilizes metal nanoparticles on the surface of the semiconductor. The characteristics of the metal, semiconductor interface allows for light to be guided in between them causing it to be scattered, allowing for more chances of absorption. The samples were fabricated using organic thin films made from polymers and metallic nanoparticles, more specifically Poly(1-vinylpyrrolidone-co-2-dimethylaminoethyl methacrylate) copolymer and silver or gold nanoparticles. The two fabrication methods applied include spin coating and Langmuir-Blodgett technique. The transport properties are obtained by analyzing the I-V curves. We will also discuss the resistance, resistivity, conductance, density of charge carriers. SUNY Oswego SCAC Grant.

  14. Prism coupling technique investigation of elasto-optical properties of thin polymer films

    Science.gov (United States)

    Ay, Feridun; Kocabas, Askin; Kocabas, Coskun; Aydinli, Atilla; Agan, Sedat

    2004-12-01

    The use of thin polymer films in optical planar integrated optical circuits is rapidly increasing. Much interest, therefore, has been devoted to characterizing the optical and mechanical properties of thin polymer films. This study focuses on measuring the elasto-optical properties of three different polymers; polystyrene, polymethyl-methacrylate, and benzocyclobutane. The out-of-plane elastic modulus, refractive index, film thickness, and birefringence of thin polymer films were determined by means of the prism coupling technique. The effect of the applied stress on the refractive index and birefringence of the films was investigated. Three-dimensional finite element method analysis was used so as to obtain the principal stresses for each polymer system, and combining them with the stress dependent refractive index measurements, the elasto-optic coefficients of the polymer films were determined. It was found that the applied stress in the out-of-plane direction of the thin films investigated leads to negative elasto-optic coefficients, as observed for all the three thin polymer films.

  15. ITO-MgF2 Film Development for PowerSphere Polymer Surface Protection

    Science.gov (United States)

    Hambourger, Paul D.; Kerslake, Thomas W.; Waters, Deborah L.

    2004-01-01

    Multi-kilogram class microsatellites with a PowerSphere electric power system are attractive for fulfilling a variety of potential NASA missions. However, PowerSphere polymer surfaces must be coated with a film that has suitable electrical sheet resistivity for electrostatic discharge control, be resistant to atomic oxygen attack, be transparent to ultraviolet light for composite structure curing and resist ultraviolet light induced darkening for efficient photovoltaic cell operation. In addition, the film must be tolerant of polymer layer folding associated with launch stowage of PowerSphere inflatable structures. An excellent film material candidate to meet these requirements is co-sputtered, indium oxide (In2O3) - tin oxide (SnO2), known as 'ITO', and magnesium fluoride (MgF2). While basic ITO-MgF2 film properties have been the subject of research over the last decade, further research is required in the areas of film durability for space-inflatable applications and precise film property control for large scale commercial production. In this paper, the authors present film durability results for a folded polymer substrate and film resistance to vacuum UV darkening. The authors discuss methods and results in the area of film sheet resistivity measurement and active control, particularly dual-channel, plasma emission line measurement of ITO and MgF2 plasma sources. ITO-MgF2 film polymer coupon preparation is described as well as film deposition equipment, procedures and film characterization. Durability testing methods are also described. The pre- and post-test condition of the films is assessed microscopically and electrically. Results show that an approx. 500A ITO-18vol% MgF2 film is a promising candidate to protect PowerSphere polymer surfaces for Earth orbit missions. Preliminary data also indicate that in situ film measurement methods are promising for active film resistivity control in future large scale production. Future film research plans are also

  16. High Seebeck effects from conducting polymer: Poly(3,4-ethylenedioxythiophene): poly(styrenesulfonate) based thin-film device with hybrid metal/polymer/metal architecture

    Energy Technology Data Exchange (ETDEWEB)

    Stanford, Michael G [ORNL; Wang, Hsin [ORNL; Ivanov, Ilia N [ORNL; Hu, Bin [University of Tennessee, Knoxville (UTK)

    2012-01-01

    Conductive polymers are of particular interest for thermoelectric applications due to their low thermal conductivity and relatively high electrical conductivity. In this study, commercially available conducting polymer poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) was used in a hybrid metal/polymer/metal thin film design in order to achieve a high Seebeck coefficient with the value of 252lV/k on a relatively low temperature scale. Polymer film thickness was varied in order to investigate its influence on the Seebeck effect. The high Seebeck coefficient indicates that the metal/polymer/metal design can develop a large entropy difference in internal energy of charge carriers between high and low-temperature metal electrodes to develop electrical potential due to charge transport in conducting polymer film through metal/polymer interface. Therefore, the metal/polymer/metal structure presents a new design to combine inorganic metals and organic polymers in thin-film form to develop Seebeck devices

  17. Control of polymer-packing orientation in thin films through synthetic tailoring of backbone coplanarity

    KAUST Repository

    Chen, Mark S.

    2013-10-22

    Controlling solid-state order of π-conjugated polymers through macromolecular design is essential for achieving high electronic device performance; yet, it remains a challenge, especially with respect to polymer-packing orientation. Our work investigates the influence of backbone coplanarity on a polymer\\'s preference to pack face-on or edge-on relative to the substrate. Isoindigo-based polymers were synthesized with increasing planarity by systematically substituting thiophenes for phenyl rings in the acceptor comonomer. This increasing backbone coplanarity, supported by density functional theory (DFT) calculations of representative trimers, leads to the narrowing of polymer band gaps as characterized by ultraviolet-visible-near infrared (UV-vis-NIR) spectroscopy and cyclic voltammetry. Among the polymers studied, regiosymmetric II and TII polymers exhibited the highest hole mobilities in organic field-effect transistors (OFETs), while in organic photovoltaics (OPVs), TBII polymers that display intermediate levels of planarity provided the highest power conversion efficiencies. Upon thin-film analysis by atomic force microscropy (AFM) and grazing-incidence X-ray diffraction (GIXD), we discovered that polymer-packing orientation could be controlled by tuning polymer planarity and solubility. Highly soluble, planar polymers favor face-on orientation in thin films while the less soluble, nonplanar polymers favor an edge-on orientation. This study advances our fundamental understanding of how polymer structure influences nanostructural order and reveals a new synthetic strategy for the design of semiconducting materials with rationally engineered solid-state properties. © 2013 American Chemical Society.

  18. Impact of nanoscale surface heterogeneity on precursor film growth and macroscopic spreading of [Rmim][NTf2] ionic liquids on mica.

    Science.gov (United States)

    Wang, Zhantao; Priest, Craig

    2013-09-10

    The connection between the interfacial properties of ionic liquids and their wetting behavior has been studied very little to date and not at all on heterogeneous surfaces. Therefore, we have investigated the static and dynamic wetting for a family of ionic liquids, 1-alkyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide, [Rmim][NTf2], on mica, where R represents an ethyl, butyl, or hexyl alkyl chain on the imidazolium ring. Spreading is impacted greatly by a precursor film that forms on both homogeneous and heterogeneous mica surfaces. Macroscopically, the initial viscous spreading of the ionic liquid droplet on bare mica occurs within seconds but is then followed by a very slow relaxation that can be closely correlated with the typical time-scales of the precursor film growth. The contact angle for [emim][NTf2] and [bmim][NTf2] relaxes from about 40° to 23° over 30 and 90 min, respectively. For [hmim][NTf2], the process takes approximately 24 h and approaches complete wetting. The thickness of the precursor films for [emim][NTf2], [bmim][NTf2], and [hmim][NTf2] were 0.53, 0.65, and 1.0 nm, respectively, according to atomic force microscopy (AFM). These values are consistent with a monolayer of ionic liquid cations on mica, rather than ion pairs. A monolayer of octadecylphosphonic acid (OPA) on mica prevents both the formation of a precursor film and the relaxation of the contact angle. However, only a partial surface coverage of ~60% OPA is required to have the same effect. Quenching of precursor film formation (and associated contact angle relaxation) is due to an increasingly connected network of OPA regions that closes the nanoscale paths of bare mica on which the precursor film can develop via surface diffusion.

  19. Thermally Induced Charge Reversal of Layer-by-Layer Assembled Single-Component Polymer Films.

    Science.gov (United States)

    Richardson, Joseph J; Tardy, Blaise L; Ejima, Hirotaka; Guo, Junling; Cui, Jiwei; Liang, Kang; Choi, Gwan H; Yoo, Pil J; De Geest, Bruno G; Caruso, Frank

    2016-03-23

    Temperature can be harnessed to engineer unique properties for materials useful in various contexts and has been shown to affect the layer-by-layer (LbL) assembly of polymer thin films and cause physical changes in preassembled polymer thin films. Herein we demonstrate that exposure to relatively low temperatures (≤ 100 °C) can induce physicochemical changes in cationic polymer thin films. The surface charge of polymer films containing primary and secondary amines reverses after heating (from positive to negative), and different characterization techniques are used to show that the change in surface charge is related to oxidation of the polymer that specifically occurs in the thin film state. This charge reversal allows for single-polymer LbL assembly to be performed with poly(allylamine) hydrochloride (PAH) through alternating heat/deposition steps. Furthermore, the negative charge induced by heating reduces the fouling and cell-association of PAH-coated planar and particulate substrates, respectively. This study highlights a unique property of thin films which is relevant to LbL assembly and biofouling and is of interest for the future development of thin polymer films for biomedical systems.

  20. Properties of solid polymer electrolyte fluorocarbon film. [used in hydrogen/oxygen fuel cells

    Science.gov (United States)

    Alston, W. B.

    1973-01-01

    The ionic fluorocarbon film used as the solid polymer electrolyte in hydrogen/oxygen fuel cells was found to exhibit delamination failures. Polarized light microscopy of as-received film showed a lined region at the center of the film thickness. It is shown that these lines were not caused by incomplete saponification but probably resulted from the film extrusion process. The film lines could be removed by an annealing process. Chemical, physical, and tensile tests showed that annealing improved or sustained the water contents, spectral properties, thermo-oxidative stability, and tensile properties of the film. The resistivity of the film was significantly decreased by the annealing process.

  1. Temperature Controlled Lateral Pattern Formation in Confined Polymer Thin Films

    Institute of Scientific and Technical Information of China (English)

    ZHANG Hao-li; David G. Bucknall

    2004-01-01

    The thermal induced topography change in a model system consisting of a polymer film on a Si substrate capped by a thin metal layer has been studied by using AFM. Regular lateral patterns over large areas were observed on the surface when the system was heated to a sufficiently high temperature. 2D-FFT analysis to the AFM images indicates that the patterns are isotropic and have well defined periodicities. The periodicities of the characteristic patterns are found to depend strongly on the annealing temperature. The study of the kinetics of the formation reveals that such a topography forms almost instantaneously once the critical temperature is reached. It is suggested that this wave-like surface morphology is driven by the thermal expansion coefficient mismatch of the different layers. This method for generating regular wave-like patterns could be used as a general method for patterning various organic materials into micro/nanostructures.

  2. Gain properties of dye-doped polymer thin films

    CERN Document Server

    Gozhyk, I; Rabbani, H; Djellali, N; Forget, S; Chenais, S; Ulysse, C; Brosseau, A; Gauvin, S; Zyss, J; Lebental, M

    2014-01-01

    The demonstration of an electrically pumped organic laser remains a major issue of organic optoelectronics for several decades. Nowadays, hybrid pumping seems a promising compromise where the organic material is optically pumped by an electrically pumped inorganic device on chip. This technical solution requires therefore an optimization of the organic gain medium under optical pumping. Here, we report a detailed study of gain features of dye-doped polymer thin films, in particular we introduce the gain efficiency $K$, in order to facilitate comparison between material and experimental conditions. First, we measure the bulk gain by the means of a pump-probe setup, and then present in details several factors which modify the actual gain of the layer, namely the confinement factor, the pump polarization, the molecular anisotropy, and the re-absorption. The usual model to evaluate the gain leads to an overestimation by more than one order of magnitude, which stresses the importance to design the devices accordin...

  3. Conductivity of oriented bis-azo polymer films

    DEFF Research Database (Denmark)

    Apitz, D.; Bertram, R.P.; Benter, N.;

    2006-01-01

    The conductivity properties of electro-optic photoaddressable, dense bis-ozo chromophore polymer films are investigated by using samples corona poled at various temperatures. A dielectric spectrometer is applied to measure the frequency dependence of the conductivity at different temperatures...... before and after heating the material to above the glass transition temperature. The results show that the orientation of the chromophores changes the charge-carrier mobility. Ionic conductivity dominates in a more disordered configuration of the material, while the competing process of hole hopping...... takes over as a transition to a liquid-crystalline phase occurs when the material is heated to much higher than the gloss transition temperature. Such micro-crystallization strongly enhances the conductivity....

  4. Band Bending in Conjugated Polymer Films: Role of Morphology and Implications for Bulk Charge Transport Characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Green, Peter [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Wenderott, J. K. [University of Michigan; Dong, Ban Xuan [University of Michigan

    2017-08-14

    The performance of power conversion devices is impacted by the energy level alignment at the interface between the conjugated polymer and conductive substrate. While band bending has been known to vary between conjugated polymers, we show that the degree of band bending within the same polymer can be just as significant with morphology change. Specifically, a significant band bending effect, studied via Kelvin probe force microscopy (KPFM), was exhibited by poly(3-hexylthiophene) (P3HT) films fabricated using matrix assisted pulsed laser evaporation (MAPLE) in contrast to the conventional spin-cast P3HT films. This finding is associated with a broadening of the density of states (DOS) in the MAPLE-deposited P3HT films, originating from the more disordered structure of the film. These findings, to the best of our knowledge, illustrate for the first time a strong connection between morphology, energy level alignment, and bulk transport in conjugated polymer films.

  5. Decohesion Kinetics of PEDOT:PSS Conducting Polymer Films

    KAUST Repository

    Dupont, Stephanie R.

    2013-10-17

    The highly conductive polymer PEDOT:PSS is a widely used hole transport layer and transparent electrode in organic electronic devices. To date, the mechanical and fracture properties of this conductive polymer layer are not well understood. Notably, the decohesion rate of the PEDOT:PSS layer and its sensitivity to moist environments has not been reported, which is central in determining the lifetimes of organic electronic devices. Here, it is demonstrated that the decohesion rate is highly sensitive to the ambient moisture content, temperature, and mechanical stress. The kinetic mechanisms are elucidated using atomistic bond rupture models and the decohesion process is shown to be facilitated by a chemical reaction between water molecules from the environment and strained hydrogen bonds. Hydrogen bonds are the predominant bonding mechanism between individual PEDOT:PSS grains within the layer and cause a significant loss in cohesion when they are broken. Understanding the decohesion kinetics and mechanisms in these films is essential for the mechanical integrity of devices containing PEDOT:PSS layers and yields general guidelines for the design of more reliable organic electronic devices. Decohesion rate in PEDOT:PSS conducting films is studied under varied environmental conditions. The moisture content in the environment is the most important factor accelerating the decohesion in the PEDOT:PSS layer, which is detrimental for device reliability. The findings on the decohesion rate and mechanisms, elucidated by atomic kinetic models, are essential for the design of more reliable organic electronic devices containting PEDOT:PSS layers. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Structure-processing-property correlations in thin films of conjugated polymer nanocomposites and blends

    Science.gov (United States)

    Sreeram, Arvind

    Conjugated polymers have found several applications in recent years, in energy conversion and storage devices such as organic light emitting diodes, solar cells, batteries, and super capacitors. Thin films of polymers used for these applications need to be mechanically and thermally stable to withstand the harsh operating conditions. Although there is significant information on the optoelectronic properties of many of these polymers, there are only few studies on their mechanical properties. There is little information in the literature on how processing of these films influence mechanical properties. In the first part of this study, poly(p-phenylene vinylene) (PPV) films were prepared by thermolytic conversion of poly[p -phenylene (tetrahydrothiophenium)ethylene chloride] precursor films, at different temperatures and the kinetics of reaction was investigated using thermogravimetry and Fourier transform infrared (FTIR) spectroscopy. The mechanical properties of the films, studied using nanoindentation, showed a dependence on the extent of conversion and chemical composition of the films. The presence of chemical defects (e.g., carbonyl groups, detected using FTIR spectroscopy), was also found to have a noticeable effect on the modulus and hardness of the films. The storage modulus, E', and plasticity decreased with an increase in conversion, whereas the loss modulus, E", showed the opposite trend. Both the precursor and the fully-converted PPV films were found to have significantly lower E" than E', consistent with the glassy nature of the polymers at room temperature. In the second part of the study, polyacetylene films were synthesized by acid-catalyzed dehydration reaction of poly(vinyl alcohol) (PVA) precursor films. The kinetics of this reaction was monitored by thermogravimetry. The chemical structure of the conjugated polymer films was characterized by Raman and IR spectroscopy. Polyacetylene films incorporated with 1-propyl-3-methylimidazolium ionic liquid

  7. Identification and design of novel polymer-based mechanical transducers: A nano-structural model for thin film indentation

    Energy Technology Data Exchange (ETDEWEB)

    Villanueva, Joshua; Huang, Qian; Sirbuly, Donald J., E-mail: dsirbuly@ucsd.edu [Department of NanoEngineering, University of California San Diego, La Jolla, California 92093 (United States)

    2014-09-14

    Mechanical characterization is important for understanding small-scale systems and developing devices, particularly at the interface of biology, medicine, and nanotechnology. Yet, monitoring sub-surface forces is challenging with current technologies like atomic force microscopes (AFMs) or optical tweezers due to their probe sizes and sophisticated feedback mechanisms. An alternative transducer design relying on the indentation mechanics of a compressible thin polymer would be an ideal system for more compact and versatile probes, facilitating measurements in situ or in vivo. However, application-specific tuning of a polymer's mechanical properties can be burdensome via experimental optimization. Therefore, efficient transducer design requires a fundamental understanding of how synthetic parameters such as the molecular weight and grafting density influence the bulk material properties that determine the force response. In this work, we apply molecular-level polymer scaling laws to a first order elastic foundation model, relating the conformational state of individual polymer chains to the macroscopic compression of thin film systems. A parameter sweep analysis was conducted to observe predicted model trends under various system conditions and to understand how nano-structural elements influence the material stiffness. We validate the model by comparing predicted force profiles to experimental AFM curves for a real polymer system and show that it has reasonable predictive power for initial estimates of the force response, displaying excellent agreement with experimental force curves. We also present an analysis of the force sensitivity of an example transducer system to demonstrate identification of synthetic protocols based on desired mechanical properties. These results highlight the usefulness of this simple model as an aid for the design of a new class of compact and tunable nanomechanical force transducers.

  8. Nanostructured thin film polymer devices for constant-rate protein delivery.

    Science.gov (United States)

    Bernards, Daniel A; Lance, Kevin D; Ciaccio, Natalie A; Desai, Tejal A

    2012-10-10

    Herein long-term delivery of proteins from biodegradable thin film devices is demonstrated, where a nanostructured polymer membrane controls release. Protein was sealed between two poly(caprolactone) films, which generated the thin film devices. Protein release for 210 days was shown in vitro, and stable activity was established through 70 days with a model protein. These thin film devices present a promising delivery platform for biologic therapeutics, particularly for application in constrained spaces.

  9. Side-group size effects on interfaces and glass formation in supported polymer thin films

    Science.gov (United States)

    Xia, Wenjie; Song, Jake; Hsu, David D.; Keten, Sinan

    2017-05-01

    Recent studies on glass-forming polymers near interfaces have emphasized the importance of molecular features such as chain stiffness, side-groups, molecular packing, and associated changes in fragility as key factors that govern the magnitude of Tg changes with respect to the bulk in polymer thin films. However, how such molecular features are coupled with substrate and free surface effects on Tg in thin films remains to be fully understood. Here, we employ a chemically specific coarse-grained polymer model for methacrylates to investigate the role of side-group volume on glass formation in bulk polymers and supported thin films. Our results show that bulkier side-groups lead to higher bulk Tg and fragility and are associated with a pronounced free surface effect on overall Tg depression. By probing local Tg within the films, however, we find that the polymers with bulkier side-groups experience a reduced confinement-induced increase in local Tg near a strongly interacting substrate. Further analyses indicate that this is due to the packing frustration of chains near the substrate interface, which lowers the attractive interactions with the substrate and thus lessens the surface-induced reduction in segmental mobility. Our results reveal that the size of the polymer side-group may be a design element that controls the confinement effects induced by the free surface and substrates in supported polymer thin films. Our analyses provide new insights into the factors governing polymer dynamics in bulk and confined environments.

  10. Effect of swift heavy ion irradiation on dielectrics properties of polymer composite films

    Energy Technology Data Exchange (ETDEWEB)

    Singh, N.L. [Physics Department, M.S. University of Baroda, Vadodara 390002 (India)]. E-mail: singhnl_msu@yahoo.com; Qureshi, Anjum [Physics Department, M.S. University of Baroda, Vadodara 390002 (India)]. E-mail: anjumqur@gmail.com; Singh, F. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India); Avasthi, D.K. [Inter University Accelerator Centre, Aruna Asaf Ali Marg, New Delhi 110067 (India)

    2007-02-25

    Ferric oxalate was used as organometallics fillers in polyvinyl chloride (PVC) to form polymer matrix composite films at different concentration of filler. These films were irradiated with 80 MeV O{sup 6+} ions at the fluences of 1 x 10{sup 11} and 1 x 10{sup 12} ions/cm{sup 2}. The radiation induced modifications in dielectric properties, microhardness, surface morphology and surface roughness of polymer composite films have been investigated at different concentration (i.e. 5%, 10% and 15%) of filler. It was observed that hardness and electrical conductivity of the films increase with the concentration of the dispersed ferric oxalate and also with the fluence. From the analysis of frequency, f, dependence of dielectric constant, {epsilon}, it has been found that the dielectric response in both pristine and irradiated samples obey the Universal law given by {epsilon} {proportional_to} f {sup n-1}. The dielectric constant/loss is observed to change significantly due to the irradiation. This suggests that ion beam irradiation promotes (i) the metal to polymer bonding and (ii) convert the polymeric structure into hydrogen depleted carbon network. Thus irradiation makes the polymer harder and more conductive. Atomic force microscopy (AFM) shows that average roughness (R {sub a}) of the irradiated films is lower than that of unirradiated films. Surface morphology of irradiated polymer composite films is observed to change. Scanning electron microscopy (SEM) results show that partial agglomeration of fillers in the polymer matrix.

  11. Polymer dielectric materials for organic thin-film transistors: Interfacial control and development for printable electronics

    Science.gov (United States)

    Kim, Choongik

    Organic thin-film transistors (OTFTs) have been extensively studied for organic electronics. In these devices, organic semiconductor-dielectric interface characteristics play a critical role in influencing OTFT operation and performance. This study begins with exploring how the physicochemical characteristics of the polymer gate dielectric affects the thin-film growth mode, microstructure, and OTFT performance parameters of pentacene films deposited on bilayer polymer (top)-SiO2 (bottom) dielectrics. Pentacene growth mode varies considerably with dielectric substrate, and correlations are established between pentacene film deposition temperature, the thin-film to bulk microstructural phase transition, and OTFT device performance. Furthermore, the primary influence of the polymer dielectric layer glass transition temperature on pentacene film microstructure and OTFT response is shown for the first time. Following the first study, the influence of the polymer gate dielectric viscoelastic properties on overlying organic semiconductor film growth, film microstructure, and TFT response are investigated in detail. From the knowledge that nanoscopically-confined thin polymer films exhibit glass transition temperatures that deviate substantially from those of the corresponding bulk materials, pentacene (p-channel) and cyanoperylene (n-channel) films grown on polymer gate dielectrics at temperatures well-below their bulk glass transition temperatures (Tg(b)) have been shown to exhibit morphological/microstructural transitions and dramatic OTFT performance discontinuities at well-defined temperatures (defined as the polymer "surface glass transition temperature," or Tg(s)). These transitions are characteristic of the particular polymer architecture and independent of film thickness or overall film cooperative chain dynamics. Furthermore, by analyzing the pentacene films grown on UV-curable polymer dielectrics with different curing times (hence, different degrees of

  12. CHARACTERIZATION AND LUMINESCENCE PROPERTIES OF THE DYE-DOPED POLYMER LANGMUIR-BLODGETT FILMS

    Institute of Scientific and Technical Information of China (English)

    Hai-peng Zheng; Rui-feng Zhang; Jin-man Huang; Ying Wu; Yu-guang Ma; Tie-jin Li; Jia-cong Shen

    1999-01-01

    1,1,4,4-Tetraphenyl-1,3-butadiene (TPB) was successfully introduced into the polymer multilayer films by means of Langmuir-Blodgett (LB) technique. Results of UV-VIS spectra and X-ray diffraction showed that the uniform films had a layer structure similar to the superlattice of organic multiple quantum wells. The electroluminescence (EL) devices fabricated from the doped polymer LB films emitted blue light.Compared with the casting films, the photoluminescence (PL) and EL spectra showed that the exciton energy shifts to higher and the half-width of the emission peak becomes narrower due to exciton confinement effect.

  13. Development of environmentally friendly piezoelectric polymer film actuator having multilayer structure

    Science.gov (United States)

    Tajitsu, Yoshiro

    2016-04-01

    We designed a new soft piezoelectric polymer actuator with a multilayer structure using the environmentally friendly polymer poly(lactic acid) (PLA). PLA is a chiral polymer having two isomers. One is poly(l-lactide) (PLLA) and the other is poly(d-lactide) (PDLA). PLLA and PDLA exhibit piezoelectric constants with opposite signs owing to their chirality. On the basis of their piezoelectric characteristics, we were able to realize a PDLA and PLLA multilayer film (PDLA/PLLA multilayer) with a simple structure. The PDLA/PLLA multilayer film of centimeter-order size exhibited a large piezoelectric resonance and its piezoelectric performance was equivalent to that of a practical piezoelectric ceramic. In this paper, as a first step toward realizing a new film actuator using the PDLA/PLLA multilayer film, we introduce the piezoelectric characteristics of a PLLA film and the concept of an actuation system using a PLLA film. Next, the fabrication process of the PDLA/PLLA multilayer film and its piezoelectric characteristics are summarized. Finally, typical examples of developed piezoelectric polymer actuation systems using a PDLA/PLLA multilayer film are described to demonstrate the potential application of piezoelectric polymer actuation systems.

  14. Preparation of Composite Films of a Conjugated Polymer and C60NWs and Their Photovoltaic Application

    Directory of Open Access Journals (Sweden)

    Takatsugu Wakahara

    2016-01-01

    Full Text Available Composite films of conjugated polymers, such as poly[2-methoxy-5-(3′,7′-dimethyloctyloxy-1,4-phenylenevinylene] (MDMO-PPV and poly(3-hexylthiophene (P3HT, with C60 nanowhiskers (C60NWs were prepared. The photoluminescence originating from the conjugated MDMO-PPV polymers was effectively quenched in the composite film, indicating a strong interaction between the conjugated polymer and C60NWs. The photovoltaic devices were fabricated using C60NW (conjugated polymer composite films, resulting in a power conversion efficiency of ~0.01% for P3HT with short length thin C60NWs, which is higher than that previously reported for thick C60 nanorods. The present study gives new guidance on the selection of the type of C60NWs and the appropriate polymer for new photovoltaic devices.

  15. Synthesis and evaluation of rosin-based polymers as film coating materials.

    Science.gov (United States)

    Satturwar, P M; Mandaogade, P M; Fulzele, S V; Darwhekar, G N; Joshi, S B; Dorle, A K

    2002-04-01

    Rosin-based polymers (R-1 and R-2) were synthesized and characterized for physicochemical properties, molecular weight (Mw), polydispersity (Mw/Mn), glass transition temperature (Tg), and thermogravimetry (TGA). Films of the polymers were cast on a mercury substrate by solvent evaporation technique. Free films were characterized for surface topography by scanning electron microscopy (SEM), water vapor transmission rate (WVTR), tensile strength, percentage elongation, and modulus of elasticity. The polymers were further evaluated as film coating materials by evaluating drug release from coated pellets with diclofenac sodium as a model drug. Drug was loaded on non-pareil seeds by a solution-layering technique and coated with varying concentrations of polymer solutions. Sustained release of the drug was observed from coated pellets. The newly synthesized rosin-based polymers promise considerable utility for pharmaceutical coating.

  16. Anchoring Strength of Thin Aligned-Polymer Films Formed by Liquid Crystalline Monomer

    Science.gov (United States)

    Murashige, Takeshi; Fujikake, Hideo; Ikehata, Seiichiro; Sato, Fumio

    2003-04-01

    We have evaluated the polar anchoring strength of a thin molecule-aligned polymer film formed by a liquid crystalline monomer. The polymer film was obtained by photopolymerization of the monomer oriented by a rubbed polyimide alignment layer in a chamber filled with N2 gas. We fabricated a nematic liquid crystal cell using the thin aligned-polymer films as alignment layers, and then evaluated the anchoring strength of the polymer by measuring the optical retardation curve of the cell driven by voltages. The experimental result showed that the anchoring strength was one order of magnitude lower than that of a conventional rubbed polyimide alignment layer, and decreased with increasing the cure temperature of the monomer film.

  17. Femtosecond Laser Desorption of Thin Polymer Films from a Dielectric Surface

    Directory of Open Access Journals (Sweden)

    Mercadier L.

    2013-11-01

    Full Text Available We desorb polymer films from fused silica with a femtosecond laser and characterize the results by atomic force microscopy. Our study as a function of beam geometry and energy reveals two ways of achieving spatially controlled nanodesorption.

  18. Flexible Surface Acoustic Wave Device with AlN Film on Polymer Substrate

    Directory of Open Access Journals (Sweden)

    Jian Zhou

    2012-01-01

    Full Text Available Surface acoustic wave device with c-axis-oriented aluminum nitride (AlN piezoelectric thin films on polymer substrates can be potentially used for development of flexible sensors, flexible microfluidic applications, microsystems, and lab-on-chip systems. In this work, the AlN films have been successfully deposited on polymer substrates using the DC reactive magnetron-sputtering method at room temperature, and the XRD, SEM, and AFM methods reveal that low deposition pressure is beneficial to the highly c-axis-oriented AlN film on polymer substrates. Studies toward the development of AlN thin film-based flexible surface acoustic wave devices on the polymer substrates are initiated and the experimental and simulated results demonstrate the devices showing the acoustic wave velocity of 9000–10000 m/s, which indicate the AlN lamb wave.

  19. Characteristics and Mechanisms in Ion-Conducting Polymer Films as Chemical Sensors

    Energy Technology Data Exchange (ETDEWEB)

    HUGHES,ROBERT C.; YELTON,WILLIAM G.; PFEIFER,KENT B.; PATEL,SANJAY V.

    2000-07-12

    Solid Polymer Electrolytes (SPE) are widely used in batteries and fuel cells because of the high ionic conductivity that can be achieved at room temperature. The ions are usually Li or protons, although other ions can be shown to conduct in these polymer films. There has been very little published work on SPE films used as chemical sensors. The authors have found that thin films of polymers like polyethylene oxide (PEO) are very sensitive to low concentrations of volatile organic compounds (VOCs) such as common solvents. Evidence of a new sensing mechanism involving the percolation of ions through narrow channels of amorphous polymer is presented. They present impedance spectroscopy of PEO films in the frequency range 0.0001 Hz to 1 MHz for different concentrations of VOCs and relative humidity. They find that the measurement frequency is important for distinguishing ionic conductivity from the double layer capacitance and the parasitic capacitance.

  20. Ellipsometry based imaging techniques for nanoscale characterization of heterogeneous polymer films

    NARCIS (Netherlands)

    Cumurcu, Aysegul

    2014-01-01

    In this thesis, hybrid methods for nanoscale characterization of heterogeneous thin polymer films were discussed. Essentially two ellipsometry based hybrid methods were established or further developed, respectively, namely electrochemical imaging ellipsometry (EC-IE) and scanning near field ellipso

  1. Enhanced transduction of photonic crystal dye lasers for gas sensing via swelling polymer film

    DEFF Research Database (Denmark)

    Smith, Cameron; Lind, Johan Ulrik; Christiansen, Mads Brøkner;

    2011-01-01

    We present the enhanced transduction of a photonic crystal dye laser for gas sensing via deposition of an additional swelling polymer film. Device operation involves swelling of the polymer film during exposure to specific gases, leading to a change in total effective refractive index. Experimental...... in its application to other intracavity-based detection schemes to enable gas sensing. © 2011 Optical Society of America....

  2. Plasmonic extinction in gold nanoparticle-polymer films as film thickness and nanoparticle separation decrease below resonant wavelength

    Science.gov (United States)

    Dunklin, Jeremy R.; Bodinger, Carter; Forcherio, Gregory T.; Keith Roper, D.

    2017-01-01

    Plasmonic nanoparticles embedded in polymer films enhance optoelectronic properties of photovoltaics, sensors, and interconnects. This work examined optical extinction of polymer films containing randomly dispersed gold nanoparticles (AuNP) with negligible Rayleigh scattering cross-sections at particle separations and film thicknesses less than (sub-) to greater than (super-) the localized surface plasmon resonant (LSPR) wavelength, λLSPR. Optical extinction followed opposite trends in sub- and superwavelength films on a per nanoparticle basis. In ˜70-nm-thick polyvinylpyrrolidone films containing 16 nm AuNP, measured resonant extinction per particle decreased as particle separation decreased from ˜130 to 76 nm, consistent with trends from Maxwell Garnett effective medium theory and coupled dipole approximation. In ˜1-mm-thick polydimethylsiloxane films containing 16-nm AuNP, resonant extinction per particle plateaued at particle separations ≥λLSPR, then increased as particle separation radius decreased from ˜514 to 408 nm. Contributions from isolated particles, interparticle interactions and heterogeneities in sub- and super-λLSPR films containing AuNP at sub-λLSPR separations were examined. Characterizing optoplasmonics of thin polymer films embedded with plasmonic NP supports rational development of optoelectronic, biomedical, and catalytic activity using these nanocomposites.

  3. Determination of the effective refractive index of porous silicon/polymer composite films

    Institute of Scientific and Technical Information of China (English)

    Zhenhong Jia

    2005-01-01

    The equation for calculating the effective refractive index of porous silicon inserted polymer was obtained by three-component Bruggeman effective medium model. The dependence of the effective refractive index of porous silicon/polymer composite films on the polymer fraction with various initial porosity was given theorically and experimentally respectively. The porous silicon and polymer polymethylmetacrylate based dispersive red one (PMMA/DR1) composite films were fabricated in our experiments. It is found that the measured effective refractive index of porous silicon inserted polymer was slightly lower than the calculated result because of the oxidization of porous silicon. The effective refractive index of oxidized porous silicon inserted polymer also was analyzed by four-component medium system.

  4. Alignment mechanism of liquid crystal in a stretched porous polymer film

    Science.gov (United States)

    Fujikake, Hideo; Kuboki, Masashi; Murashige, Takeshi; Sato, Hiroto; Kikuchi, Hiroshi; Kurita, Taiichiro

    2003-09-01

    This article discusses the mechanism of nematic liquid crystal alignment in stretched porous polymer films. The polymer films were formed by extreme stretching of an isotropic porous polyolefin, such that the draw ratio was 12:1. A 6-μm-thick porous film with a high porosity coefficient of 92% revealed fine string-shaped areas that exhibited optical anisotropy due to their possessing a high degree of molecular alignment. The porous film was filled with nematic liquid crystal and then the composite film was sandwiched between transparent electrodes coated onto glass substrates, without the use of conventional alignment layers. From polarizing microscopy observations it was found that the string-like polymer areas induce liquid crystal molecular alignment. The liquid crystal cells can exhibit an electrically controlled birefringence effect. This alignment technique enables us to realize three-dimensional control of liquid crystal alignment.

  5. Relaxation and Flow of Polymer Thin Films in Isothermal Temperature Jump Measurements

    Science.gov (United States)

    Beaucage, G.; Banach, M. J.; Vaia, R. A.

    2000-03-01

    The dynamic behavior of thin polymer films is of interest in fabrication of microelectronics, optoelectronics and for the coatings industry. It is known that polymer relaxation is effected by film thickness and by the particular substrate/polymer pair. Recently, we have used a spectroscopic ellipsometer to investigate the glass transition in thin films. In addition to information on modification of thermal transitions, the spectroscopic ellipsometer allows for direct observation of the isothermal dimensions of a thin polymer film as a function of time following a rapid temperature change. Recent results will be presented on the observation of time dependence in film-normal thickness and normalized, in-plane, lateral dimension (explained in talk) as well as simple fits to this relaxation behavior in terms of a normalized viscosity and relaxation time. Initial results support a highly asymmetric initial thermal expansion followed by close to isotropic relaxation and anisotropic flow. These features may elucidate models for chain orientation in thin polymer films. Beaucage, G.; Composto, R.; Stein, R.S. (1993). J. Poly. Sci., Polym. Phys. Ed., 31 319. Kovacs, A. J.; Hutchinson, J. M.; Aklonis, J. J. (1977) in "The Structure of Non-Crystalline Materials", Ed. P. H. Gaskell, Taylor and Francis, London. Banach, M. J.; Clarson, S. J.; Beaucage, G.; Kramer, E. J.; Benkoski, J.; Vaia, R. Submitted Macromolecules (1999). Beaucage, G.; Banach, M. J.; Vaia, R. A. Submitted Macromolecules (1999).

  6. PHOTORESPONSIVE BEHAVIOR OF AZOBENZENE-BASED (METH)ACRYLIC (CO)POLYMERS IN THIN-FILMS

    NARCIS (Netherlands)

    HAITJEMA, HJ; VONMORGEN, GL; TAN, YY; CHALLA, G

    1994-01-01

    The reversible photoisomerization and the thermal isomerization of azobenzene-based (Az.b.) groups covalently bound to (meth)acrylic (co)polymers were investigated in thin films. For the amorphous polymers it was found that a broad range of the thermal cis --> trans isomerization rates could be obta

  7. Thin Films Formed from Conjugated Polymers with Ionic, Water-Soluble Backbones

    NARCIS (Netherlands)

    Voortman, Thomas P; Chiechi, Ryan C

    2015-01-01

    This paper compares the morphologies of films of conjugated polymers in which the backbone (main chain) and pendant groups are varied between ionic/hydrophilic and aliphatic/hydrophobic. We observe that conjugated polymers in which the pendant groups and backbone are matched, either ionic-ionic or h

  8. Single-domain shape anisotropy in near-macroscopic Ni80Fe20 thin-film rectangles

    Science.gov (United States)

    Li, Yi; Lu, Yiran; Bailey, W. E.

    2013-05-01

    Shape anisotropy provides a simple mechanism to adjust the local bias field in patterned structures. It is well known that for ellipsoidal particles elements, domain formation is thought to limit the effectiveness of shape anisotropy. In our work, we show that very soft lithographically patterned Ni80Fe20 films with control of induced magnetic anisotropy can exhibit shape anisotropy fields in agreement with single-domain models, for both hysteresis loop measurements at low field and ferromagnetic resonance measurements at high field. We show the superiority of the fluxmetric form over the magnetometric form of anisotropy estimate for thin films with control dimensions from 10 μm to 150 μm and in-plane aspect ratios above 10.

  9. A novel mucoadhesive polymer film composed of carbopol, poloxamer and hydroxypropylmethylcellulose.

    Science.gov (United States)

    Kim, Tae Hee; Ahn, Jae Soon; Choi, Hoo Kyun; Choi, Yun Jaie; Cho, Chong Su

    2007-03-01

    Using the casting method novel mucoadhesive polymer blend film consisting of Carbopol, poloxamer, and hydroxypropylmethylcellulose (HPMC) was prepared and characterized. Triamcinolone acetonide (TAA) was loaded into Carbopol/poloxamer/HPMC polymer blend film. Carbonyl band of Carbopol in Carbopol/poloxamer/HPMC shifted to longer wavenumber than that of Carbopol in Carbopol/poloxamer due to the hydrogen bonding among Carbopol, poloxamer, and HPMC. Tan delta peak assigned to glass transition temperature (Tg) of HPMC shifted to low temperature due to increased flexibility caused by increased poloxamer content in polymer blend films. Swelling ratio of Carbopol/poloxamer/HPMC films was lowest in Carbopoll poloxamer/HPMC at mixing ratio of 35/30/35 (wt/wt/wt). Adhesive force of Carbopol/poloxamer/HPMC films increased with increasing HPMC content in Carbopol/poloxamer/HPMC polymer blend film and increasing hydroxypropyl group content in HPMC due to hydrophobic property of HPMC although bioadhesive force was highest at mixing ratio of 35/30/35 (wt/wt/ wt). Release of TAA from TAA-loaded Carbopol/poloxamer/HPMC polymer blend film in vitro increased with increasing loading content of drug.

  10. Multi-Stimuli-Responsive Polymer Materials: Particles, Films, and Bulk Gels.

    Science.gov (United States)

    Cao, Zi-Quan; Wang, Guo-Jie

    2016-06-01

    Stimuli-responsive polymers have received tremendous attention from scientists and engineers for several decades due to the wide applications of these smart materials in biotechnology and nanotechnology. Driven by the complex functions of living systems, multi-stimuli-responsive polymer materials have been designed and developed in recent years. Compared with conventional single- or dual-stimuli-based polymer materials, multi-stimuli-responsive polymer materials would be more intriguing since more functions and finer modulations can be achieved through more parameters. This critical review highlights the recent advances in this area and focuses on three types of multi-stimuli-responsive polymer materials, namely, multi-stimuli-responsive particles (micelles, micro/nanogels, vesicles, and hybrid particles), multi-stimuli-responsive films (polymer brushes, layer-by-layer polymer films, and porous membranes), and multi-stimuli-responsive bulk gels (hydrogels, organogels, and metallogels) from recent publications. Various stimuli, such as light, temperature, pH, reduction/oxidation, enzymes, ions, glucose, ultrasound, magnetic fields, mechanical stress, solvent, voltage, and electrochemistry, have been combined to switch the functions of polymers. The polymer design, preparation, and function of multi-stimuli-responsive particles, films, and bulk gels are comprehensively discussed here.

  11. Gelatin/hydroxypropyl methylcellulose matrices - Polymer interactions approach for oral disintegrating films.

    Science.gov (United States)

    Tedesco, Marcela P; Monaco-Lourenço, Carla A; Carvalho, Rosemary A

    2016-12-01

    Oral disintegrating film represents an optimal alternative for delivery system of active compounds. The choice of film-forming polymer is the first step in the development of oral disintegrating films and the knowledge of molecular interactions in this matrix is fundamental to advance in this area. Therefore, this study aimed to characterize gelatin and hydroxypropyl methylcellulose (HPMC) films and their blends as matrices of oral disintegrating films. The films were produced by casting technique and were characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, differential scanning calorimetry, mechanical properties, contact angle, time disintegration and bioadhesive strength. Differential scanning calorimetry showed that enthalpy of fusion and melting temperatures of the blends films were lower than those of the gelatin film, which may be associated with the lack of intra-chain interactions also observed in the Fourier transform infrared spectra. In blends, a less compact cross-section structure was observed in scanning electron microscopy images compared with isolated polymer films. The addition of HPMC increased the elongation, hydrophilicity and in vitro bioadhesive force and decreased in vitro disintegration time, important properties in the development of oral disintegrating films. Although the mixture of the polymers showed no synergistic behavior, this study may contribute to the development of new applications for polymeric matrices in the pharmaceutical industry.

  12. Novel thin film polymer foaming technique for low and ultra low-k dielectrics

    NARCIS (Netherlands)

    Krause, B.; Koops, G.H.; Vegt, van der N.F.A.; Wessling, M.; Wubbenhorst, M.; Turnhout, van J.

    2001-01-01

    The results presented show a novel route for the preparation of thin ultra-low-k polymer films based on commercial and "non-exotic" (non-expensive) polyimide by a foaming technique. Dependent on the glass transition temperature of the polyimide mechanically and thermally stable (> 300 °C) films havi

  13. Characteristics and cytocompatibility of biodegradable polymer film on magnesium by spin coating.

    Science.gov (United States)

    Xu, Liping; Yamamoto, Akiko

    2012-05-01

    In recent years, magnesium and its alloys have been investigated as biodegradable metallic materials in cardiovascular stents and bone implants. However, rapid corrosion rate in the early stage of the degradation process greatly influences the cytocompatibility and hinters their application. In this research, biodegradable polymer films are prepared under same coating condition by spin coating in order to improve the early corrosion resistance and cytocompatibility of Mg. The results present that uniform, nonporous, amorphous PLLA and semi-crystalline PCL films are coated on Mg. PLLA film shows better adhesion strength to Mg substrate than that of PCL film. For both PLLA and PCL, low molecular weight (LMW) film is thinner and exhibits better adhesion strength than high molecular weight (HMW) one. SaOS-2 cells show significantly good attachment and high growth on the polymer-coated Mg, demonstrating that all the polymer films can significantly improve the cytocompatibility in the 7-day incubation. The pH measurement of the immersion medium and the quantification of released Mg(2+) during the cell culture clearly indicate that the corrosion resistance of Mg substrate is improved by the polymer films to different extents. It can be concluded that both PLLA and PCL films are promising protective coatings for improving the initial corrosion resistance and cytocompatibility.

  14. Photoconductivity of Polymer Composite Films Containing an Mn(III)/Cu(II) Complex

    Science.gov (United States)

    Davidenko, N. A.; Kokozay, V. N.; Petrusenko, S. R.; Stetsyuk, O. N.; Studzinsky, S. L.; Davidenko, I. I.

    2013-11-01

    We have studied the optical, photoelectric and dielectric properties of polymer composite films based on polyvinyl butyral with additives of a mixed-metal Mn(III)/Cu(II) complex. We observed high photoconductivity of the films obtained in the region of absorption by the complex. The slow photocurrent rise and relaxation kinetics are connected with the low mobility of the photogenerated charge carriers.

  15. Measurement of interfacial toughness of metal film wire and polymer membrane through electricity induced buckling method.

    Science.gov (United States)

    Wang, Qinghua; Xie, Huimin; Lu, Jian; Chen, Pengwan; Zhang, Qingming

    2011-06-15

    Measurement of interfacial toughness of a metal film wire and a flexible substrate is a challenging issue for evaluating the interfacial bonding capacity of the film-wire/substrate systems. In this paper, an electricity induced buckling method is proposed to measure the interfacial toughness between a metal film wire and a polymer membrane, which does not use a pre-existing weak interface. This method relies on causing a buckling driven delamination of the metal film wire from the polymer membrane, by inducing a compressive stress due to electrification of the film wire. For a sort of structure formed by a constantan film wire and a polymer membrane, the current density range under which the buckling of the film wire will emerge is obtained from experiments. The average interfacial toughness of one typical sample is measured to be 31.6 J/m(2). According to the buckling topographies under different current densities, the interfacial toughness of the constantan film wire and the polymer substrate is found to vary from 10 J/m(2) to 60 J/m(2).

  16. Zinc-Based Semiconductors/Polymer Thin Films Junction for Photovoltaic Application

    OpenAIRE

    Souad Al-bat’hi; K. A. Buhari; Latiff, M. I.

    2012-01-01

    Thin films of ZnO and ZnTe semiconductors were deposited on ITO conducting glass substrates by sputtering and electrodeposition techniques, respectively. On the other hand, thin films of ion conducting solid polymer electrolyte were prepared by solution cast technique. The polymer is a blend of 50 wt% polyethylene oxide and 50 wt% chitosan. To provide redox couple (I−/I3−), the polymer was complexed with ammonium iodide NH4I with addition of few crystals of iodine I2. Ammonium iodide NH4I was...

  17. Zinc-Based Semiconductors/Polymer Thin Films Junction for Photovoltaic Application

    OpenAIRE

    Souad Al-bat’hi; K. A. Buhari; M. I. Latiff

    2012-01-01

    Thin films of ZnO and ZnTe semiconductors were deposited on ITO conducting glass substrates by sputtering and electrodeposition techniques, respectively. On the other hand, thin films of ion conducting solid polymer electrolyte were prepared by solution cast technique. The polymer is a blend of 50 wt% polyethylene oxide and 50 wt% chitosan. To provide redox couple (I−/I3−), the polymer was complexed with ammonium iodide NH4I with addition of few crystals of iodine I2. Ammonium iodide NH4I was...

  18. Electro-optical properties of polymer stabilized cholesteric liquid crystal film

    Institute of Scientific and Technical Information of China (English)

    Ma Ji; Zheng Zhi-Gang; Liu Yong-Gang; Xuan Li

    2011-01-01

    Liquid crystals (LCs) and polymers are extensively used in various electro-optical applications. In this paper, normal mode polymer stabilized cholesteric LC film is prepared and studied. The effects of chiral dopant and monomer concentrations on the electro-optical properties, such as contrast ratio, driving voltage, hysteresis width and response time, are investigated. The reasons of electro-optical properties influenced by the concentrations of the materials are discussed. Through the proper material recipe, the electro-optical properties of polymer stabilized cholesteric LC film can be optimized.

  19. Chain relaxation in thin polymer films: turning a dielectric type-B polymer into a type-A' one.

    Science.gov (United States)

    Solar, Mathieu; Paul, Wolfgang

    2017-02-22

    A molecular dynamics simulation study of chain relaxation in a thin polymer film is presented, studying the dielectric response of a random copolymer of cis and trans 1,4-polybutadiene, a type B polymer without net chain dipole moment, confined between graphite walls. We stress the orientational effect of the attractive walls, inducing polarization in the vicinity of the walls, while the center of the film stays bulk-like. This polarization leads to a net dipole moment of the adsorbed chains, which is perpendicular to their end-to-end vector, which we termed as type A' behavior. In this situation, the dipole moment relaxes only upon desorption of the chains from the wall, a dynamic process which occurs on timescales much longer than the bulk relaxation time of the polymer.

  20. Growth and characterization of CdS thin films on polymer substrates for photovoltaic applications.

    Science.gov (United States)

    Park, Yongseob; Kim, Eung Kwon; Lee, Suho; Lee, Jaehyeong

    2014-05-01

    In this work, cadmium sulfide (CdS) films were deposited on flexible polymer substrates such as polycarbonate (PC) and polyethylene terephthalate (PET). The r.f. magnetron sputtering, which is cost-effective scalable technique, was used for the film deposition. The structural and optical properties of the films grown at different sputtering pressures were investigated. When the CdS film was deposited at lower pressure, the crystallinity and the preferred orientation toward c-axis in hexagonal phase was improved. However, the optical transmittance was reduced as the sputtering pressure was decreased. Compared with the glass substrate, CdS films grown on polymer substrates were exhibited some wore structural and optical characteristics. CdTe thin film solar cell applied to sputtered CdS as a window layer showed a maximum efficiency of 11.6%.

  1. Temperature- and thickness-dependent elastic moduli of polymer thin films.

    Science.gov (United States)

    Ao, Zhimin; Li, Sean

    2011-03-22

    The mechanical properties of polymer ultrathin films are usually different from those of their counterparts in bulk. Understanding the effect of thickness on the mechanical properties of these films is crucial for their applications. However, it is a great challenge to measure their elastic modulus experimentally with in situ heating. In this study, a thermodynamic model for temperature- (T) and thickness (h)-dependent elastic moduli of polymer thin films Ef(T,h) is developed with verification by the reported experimental data on polystyrene (PS) thin films. For the PS thin films on a passivated substrate, Ef(T,h) decreases with the decreasing film thickness, when h is less than 60 nm at ambient temperature. However, the onset thickness (h*), at which thickness Ef(T,h) deviates from the bulk value, can be modulated by T. h* becomes larger at higher T because of the depression of the quenching depth, which determines the thickness of the surface layer δ.

  2. Physical and Degradable Properties of Mulching Films Prepared from Natural Fibers and Biodegradable Polymers

    Directory of Open Access Journals (Sweden)

    Zhijian Tan

    2016-05-01

    Full Text Available The use of plastic film in agriculture has the serious drawback of producing vast quantities of waste. In this work, films were prepared from natural fibers and biodegradable polymers as potential substitutes for the conventional non-biodegradable plastic film used as mulching material in agricultural production. The physical properties (e.g., mechanical properties, heat preservation, water permeability, and photopermeability and degradation characteristics (evaluated by micro-organic culture testing and soil burial testing of the films were studied in both laboratory and field tests. The experimental results indicated that these fiber/polymer films exhibited favorable physical properties that were sufficient for use in mulching film applications. Moreover, the degradation degree of the three tested films decreased in the following order: fiber/starch (ST film > fiber/poly(vinyl alcohol (PVA film > fiber/polyacrylate (PA film. The fiber/starch and fiber/PVA films were made from completely biodegradable materials and demonstrated the potential to substitute non-biodegradable films.

  3. Selective scattering polymer dispersed liquid crystal film for light enhancement of organic light emitting diode.

    Science.gov (United States)

    Jiang, Jinghua; McGraw, Greg; Ma, Ruiqing; Brown, Julie; Yang, Deng-Ke

    2017-02-20

    We developed a novel light enhancing film for an organic light emitting diode (OLED) based on polymer dispersed liquid crystal (PDLC). In the film, the liquid crystal droplets are unidirectionally aligned along the film normal direction and exhibit selective scattering. The film scatters light emitted only in directions with large incident angles but not light emitted in directions with small incident angles. When the light is scattered, it changes propagation direction and exits the OLED. The PDLC film reduces the total internal reflection and thus can significantly increase the light efficiency of the OLED.

  4. Surface-mounted MOF templated fabrication of homochiral polymer thin film for enantioselective adsorption of drugs.

    Science.gov (United States)

    Gu, Zhi-Gang; Fu, Wen-Qiang; Liu, Min; Zhang, Jian

    2017-01-26

    A self-polymerized chiral monomer 3,4-dihydroxy-l-phenylalanine (l-DOPA) has been introduced into the pores of an achiral surface-mounted metal organic framework (SURMOF), and then the homochiral poly(l-DOPA) thin film has been successfully formed after UV light irradiation and etching of the SURMOF. Remarkably, such a poly(l-DOPA) thin film exhibited enantioselective adsorption of naproxen. This study opened a SURMOF-templated approach for preparing porous polymer thin films.

  5. Study of Different Technologies for Film Coating of Drug Layered Pellets Using Ethylcellulose as Functional Polymer

    OpenAIRE

    Melegari, Cecilia

    2016-01-01

    The research project focused on the study of different technologies for film coating of pellets using ethylcellulose as barrier-membrane coating polymer. In particular, two different approaches were investigated: the conventional aqueous film coating and the dry powder coating methods. The research carried out during the first part of the PhD provided a comprehensive study of the conventional aqueous film coating process of guaifenesin-loaded pellets in order to understand the variables af...

  6. Physical and Degradable Properties of Mulching Films Prepared from Natural Fibers and Biodegradable Polymers

    OpenAIRE

    Zhijian Tan; Yongjian Yi; Hongying Wang; Wanlai Zhou; Yuanru Yang; Chaoyun Wang

    2016-01-01

    The use of plastic film in agriculture has the serious drawback of producing vast quantities of waste. In this work, films were prepared from natural fibers and biodegradable polymers as potential substitutes for the conventional non-biodegradable plastic film used as mulching material in agricultural production. The physical properties (e.g., mechanical properties, heat preservation, water permeability, and photopermeability) and degradation characteristics (evaluated by micro-organic cultur...

  7. Synthesis and Characterization of Thin Film Lithium-Ion Batteries Using Polymer Electrolytes

    Science.gov (United States)

    Maranchi, Jeffrey P.; Kumta, Prashant N.; Hepp, Aloysius F.; Raffaelle, Ryne P.

    2002-01-01

    The present paper describes the integration of thin film electrodes with polymer electrolytes to form a complete thin film lithium-ion battery. Thin film batteries of the type, LiCoO2 [PAN, EC, PC, LiN(CF3SO2)2] SnO2 have been fabricated. The results of the synthesis and characterization studies will be presented and discussed.

  8. Water Vapor Permeation of Metal Oxide/Polymer Coated Plastic Films

    Science.gov (United States)

    Numata, Yukihiro; Oya, Toshiyuki; Kuwahara, Mitsuru; Ito, Katsuya

    Barrier performance to water vapor permeation of ceramic coated layers deposited on flexible polymer films is of great interest to food packaging, medical device packaging and flat panel display industries. In this study, a new type film in which a ceramic layer is deposited on a polymer coated film was proposed for lower water vapor permeation. It is important how to control interfacial properties between each layer and film for good barrier performance. Several kinds of polymer coated materials were prepared for changing surface free energy of the films before and after depositing the ceramic layer. The ceramic layer, which is composed of mixed material of SiO2 and Al2O3, was adopted under the same conditions. The following results were obtained; 1) Water vapor permeation is not related to the surface energy of polymer coated films, 2) After depositing the ceramic layer, however, a strong correlation is observed between the water vapor permeation and surface free energy. 3) The phenomenon is considered that the polarity of the polymer layers plays a key role in changing the structure of ceramic coated layers.

  9. Influence of macromolecular architecture on necking in polymer extrusion film casting process

    Energy Technology Data Exchange (ETDEWEB)

    Pol, Harshawardhan; Banik, Sourya; Azad, Lal Busher; Doshi, Pankaj; Lele, Ashish [CSIR-National Chemical Laboratory, Pune, Maharashtra (India); Thete, Sumeet [Purdue University, West Lafayette, Indiana (United States)

    2015-05-22

    Extrusion film casting (EFC) is an important polymer processing technique that is used to produce several thousand tons of polymer films/coatings on an industrial scale. In this research, we are interested in understanding quantitatively how macromolecular chain architecture (for example long chain branching (LCB) or molecular weight distribution (MWD or PDI)) influences the necking and thickness distribution of extrusion cast films. We have used different polymer resins of linear and branched molecular architecture to produce extrusion cast films under controlled experimental conditions. The necking profiles of the films were imaged and the velocity profiles during EFC were monitored using particle tracking velocimetry (PTV) technique. Additionally, the temperature profiles were captured using an IR thermography and thickness profiles were calculated. The experimental results are compared with predictions of one-dimensional flow model of Silagy et al{sup 1} wherein the polymer resin rheology is modeled using molecular constitutive equations such as the Rolie-Poly (RP) and extended Pom Pom (XPP). We demonstrate that the 1-D flow model containing the molecular constitutive equations provides new insights into the role of macromolecular chain architecture on film necking.{sup 1}D. Silagy, Y. Demay, and J-F. Agassant, Polym. Eng. Sci., 36, 2614 (1996)

  10. Spin-Casting Polymer Brush Films for Stimuli-Responsive and Anti-Fouling Surfaces.

    Science.gov (United States)

    Xu, Binbin; Feng, Chun; Hu, Jianhua; Shi, Ping; Gu, Guangxin; Wang, Lei; Huang, Xiaoyu

    2016-03-01

    Surfaces modified with amphiphilic polymers can dynamically alter their physicochemical properties in response to changes of their environmental conditions; meanwhile, amphiphilic polymer coatings with molecular hydrophilic and hydrophobic patches, which can mitigate biofouling effectively, are being actively explored as advanced coatings for antifouling materials. Herein, a series of well-defined amphiphilic asymmetric polymer brushes containing hetero side chains, hydrophobic polystyrene (PS) and hydrophilic poly(ethylene glycol) (PEG), was employed to prepare uniform thin films by spin-casting. The properties of these films were investigated by water contact angle, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and quartz crystal microbalance (QCM). AFM showed smooth surfaces for all films with the roughness less than 2 nm. The changes in water contact angle and C/O ratio (XPS) evidenced the enrichment of PEG or PS chains at film surface after exposed to selective solvents, indicative of stimuli- responsiveness. The adsorption of proteins on PEG functionalized surface was quantified by QCM and the results verified that amphiphilic polymer brush films bearing PEG chains could lower or eliminate protein-material interactions and resist to protein adsorption. Cell adhesion experiments were performed by using HaCaT cells and it was found that polymer brush films possess good antifouling ability.

  11. Nonwettable Thin Films from Hybrid Polymer Brushes can be Hydrophilic

    Science.gov (United States)

    2007-03-30

    2006 Hybrid brushes composed of two liquid polymers, poly(dimethylsiloxane) (PDMS) and a highly branched ethoxylated polyethylenimine (EPEI), were...liquid polymers, poly(dimethylsiloxane) (PDMS) and a highly branched ethoxylated polyethylenimine (EPEI; Figure 1). We demonstrate here that hybrid... ethoxylated (highly branched, symmetrical polymer; about 80% of the primary and secondary amines are ethoxylated ), 37% solution in water (EPEI Mw

  12. Thin metal film-polymer composite for efficient optoacoustic generation (Conference Presentation)

    Science.gov (United States)

    Lee, Taehwa; Guo, L. Jay

    2016-03-01

    Photoacoustic (PA) conversion of metal film absorbers is known to be inefficient because of their low thermal expansion and high light reflectance, as compared to polymeric materials containing light absorbing fillers. Specifically, the PA signal for metal films is typically an order of magnitude lower than those for PDMS-based composites consisting of carbon materials such as carbon blacks, carbon nanotubes, and carbon fibers. However, the carbon-PDMS composites have several disadvantages, e.g., difficulty in controlling film thickness, aggregation of the carbon fillers, and poor patternablility. To overcome these issues and achieve comparable PA amplitudes, a polymer-metal film composite was developed consisting of a thin metal absorber and adjacent transparent polymer layers. The proposed structure shows efficient PA conversion. The measured PA amplitude of the metal film composite is an order of magnitude higher than that of metal-only samples, and comparable to those of the carbon-PDMS composites. The enhanced PA conversion is accomplished by using metal film of a few tens of nanometers, which greatly facilitates heat transfer from the metal film to the surrounding polymers. Moreover, integrating the metal film composite with a photonic cavity can compensate light absorption loss of the thinner metal film. Theoretical and experimental analysis is conducted for understanding the mechanism behind such improvement. This strategy could be implemented for spatial PA signal patterns, especially for deep tissue PA imaging of implants or image-guiding tools. Furthermore, this approach also provides a guideline for designing photoacoustic transmitters and contrast agents.

  13. Engineering the Crystalline Morphology of Polymer Thin Films via Physical Vapor Deposition

    Science.gov (United States)

    Jeong, Hyuncheol; Arnold, Craig; Priestley, Rodney

    Thin-film growth via physical vapor deposition (PVD) has been successfully exploited for the delicate control of film structure for molecular and atomic systems. The application of such a high-energetic process to polymeric film growth has been challenged by chemical degradation. However, recent development of Matrix Assisted Pulsed Laser Evaporation (MAPLE) technique opened up a way to deposit a variety of macromolecules in a PVD manner. Here, employing MAPLE technique to the growth of semicrystalline polymer thin films, we show the engineering of crystalline film morphology can be achieved via manipulation of substrate temperature. This is accomplished by exploiting temperature effect on crystallization kinetics of polymers. During the slow film growth crystallization can either be permitted or suppressed, and crystal thickness can be tuned via temperature modulation. In addition, we report that the crystallinity of polymer thin films may be significantly altered with deposition temperature in MAPLE processing. We expect that this ability to manipulate crystallization kinetics during polymeric film growth will open the possibility to engineer structure in thin film polymeric-based devices in ways that are difficult by other means.

  14. Synthesis and characterization thin films of conductive polymer (PANI) for optoelectronic device application

    Science.gov (United States)

    Jarad, Amer N.; Ibrahim, Kamarulazizi; Ahmed, Nasser M.

    2016-07-01

    In this work we report preparation and investigation of structural and optical properties of polyaniline conducting polymer. By using sol-gel in spin coating technique to synthesize thin films of conducting polymer polyaniline (PANI). Conducting polymer polyaniline was synthesized by the chemical oxidative polymerization of aniline monomers. The thin films were characterized by technique: Hall effect, High Resolution X-ray diffraction (HR-XRD), Fourier transform infrared (FTIR) spectroscopy, Field emission scanning electron microscopy (FE-SEM), and UV-vis spectroscopy. Polyaniline conductive polymer exhibit amorphous nature as confirmed by HR-XRD. The presence of characteristic bonds of polyaniline was observed from FTIR spectroscopy technique. Electrical and optical properties revealed that (p-type) conductivity PANI with room temperature, the conductivity was 6.289×10-5 (Ω.cm)-1, with tow of absorption peak at 426,805 nm has been attributed due to quantized size of polyaniline conducting polymer.

  15. Synthesis and characterization thin films of conductive polymer (PANI) for optoelectronic device application

    Energy Technology Data Exchange (ETDEWEB)

    Jarad, Amer N., E-mail: amer78malay@yahoo.com.my; Ibrahim, Kamarulazizi, E-mail: kamarul@usm.my; Ahmed, Nasser M., E-mail: nas-tiji@yahoo.com [Nano-optoelectronic Research and Technology Laboratory School of physics, University of Sains Malaysia, 11800 Pulau Pinang (Malaysia)

    2016-07-06

    In this work we report preparation and investigation of structural and optical properties of polyaniline conducting polymer. By using sol-gel in spin coating technique to synthesize thin films of conducting polymer polyaniline (PANI). Conducting polymer polyaniline was synthesized by the chemical oxidative polymerization of aniline monomers. The thin films were characterized by technique: Hall effect, High Resolution X-ray diffraction (HR-XRD), Fourier transform infrared (FTIR) spectroscopy, Field emission scanning electron microscopy (FE-SEM), and UV-vis spectroscopy. Polyaniline conductive polymer exhibit amorphous nature as confirmed by HR-XRD. The presence of characteristic bonds of polyaniline was observed from FTIR spectroscopy technique. Electrical and optical properties revealed that (p-type) conductivity PANI with room temperature, the conductivity was 6.289×10{sup −5} (Ω.cm){sup −1}, with tow of absorption peak at 426,805 nm has been attributed due to quantized size of polyaniline conducting polymer.

  16. Measuring Exciton Diffusion in Conjugated Polymer Films with Super-resolution Microscopy

    Science.gov (United States)

    Penwell, Samuel; Ginsberg, Lucas; Noriega Manez, Rodrigo; Ginsberg, Naomi

    2015-03-01

    Conjugated polymers are highly tunable organic semiconductors, which can be solution processed to form thin films, making them prime candidates for organic photovoltaic devices. One of the most important parameters in a conjugated polymer solar cell is the exciton diffusion length, which depends on intermolecular couplings, and is typically on the order of 10 nm. This mean exciton migration can vary dramatically between films and within a single film due to heterogeneities in morphology on length scales of 10's to 100's nm. To study the variability of exciton diffusion and morphology within individual conjugated polymer films, we are adapting stimulated emission depletion microscopy. STED is typically used in biology with well-engineered fluorescent labels or on NV-centers in diamond. I will, however, describe how we have demonstrated STED in conjugated polymer films of MEH-PPV and CN-PPV by taking care to first understand the film's photophysical properties. This new approach provides a way to study exciton diffusion by utilizing subdiffraction optical excitation volumes. In this way, we will obtain a spatiotemporal map of exciton distributions that will help to correlate the energetic landscape to film morphology at the nanoscale. This research is supported in part by the Department of Energy Office of Science Graduate Fellowship Program (DOE SCGF), made possible in part by the American Recovery and Reinvestment Act of 2009, administered by ORISE-ORAU under Contract No. DE-AC05-06.

  17. Heat transport in polymer thin films for micro/nano-manufacturing

    Science.gov (United States)

    Hung, Ming-Tsung

    The rapid growth in micro/nanotechnology has opened a great opportunity for polymer thin films and polymer nanocomposites. Thermal management or thermal effects in those applications need to be carefully examined. For example, the local heating in electron-beam lithography, emersion lithography, and scanning near field optical lithography may cause the degradation of photoresists and reduce the resolution. The development of many organic electronics, polymer micro-electro-mechanical-systems (MEMS) devices, and polymer nanocomposites may require the knowledge of heat transport in micro/nano-sized polymers. Thermolithography, a novel lithography, uses controlled localized heating to transfer patterns and requires the thermal conductivity data to control. It is of considerable scientific and technological interests for study heat transport in polymer thin films. Unlike bulk polymers that can be measured using commercially available instruments, polymer thin films are difficult to measure. In this manuscript, we develop the measurement techniques suitable for measuring thermal conductivity of polymer thin films and polymer nanocomposites. Using a microfabricated membrane-based device, we study the heat conduction in photoresists at difference process stages. This data is used in our thermolithography study, where we use microheater to study the kinetic of crosslinking reaction of photoresist. The feasibility of thermolithography and potential three dimensional micro/nano-fabrication is presented. The uniqueness of thermolithography is also demonstrated by patterning amorphous fluoropolymers. A modified hot-wire technique is used to measure the thermal conductivity of graphite nanoplatelet (GNP) reinforced nanocomposites, one of the promising candidates for multifunctional materials. Thermal interface resistance in GNP nanocomposites is investigated, which shows a strong effect on energy transport in the nanocomposites and can be diminished through surface treatment.

  18. Investigating the crystal growth behavior of biodegradable polymer blend thin films using in situ atomic force microscopy

    CSIR Research Space (South Africa)

    Malwela, T

    2014-01-01

    Full Text Available This article reports the crystal growth behavior of biodegradable polylactide (PLA)/poly[(butylene succinate)-co-adipate] (PBSA) blend thin films using atomic force microscopy (AFM). Currently, polymer thin films have received increased research...

  19. Elucidation of charge storage characteristics of conducting polymer film using redox reaction

    CERN Document Server

    Contractor, Asfiya Q

    2013-01-01

    A general technique to investigate charge storage characteristics of conducting polymer films has been developed. A redox reaction is conducted on a polymer film on a rotating disk electrode under potentiostatic condition so that the rate of charging of the film equals the rate of removal of the charge by the reaction. In an experiment on polyaniline film deposited on platinum substrate, using Fe2+/Fe3+ in HCl as the redox system, the voltammogram shows five distinct linear segments (bands) with discontinuity in the slope at specific transition potentials. These bands are the same as those indicated by ESR/Raman spectroscopy with comparable transition potentials. From the dependence of the slopes of the bands on concentration of ferrous and ferric ions, it was possible to estimate the energies of the charge carrier in different bands. It is shown that the charge storage in the film is capacitive.

  20. Ion-beam modifications of the surface morphology and conductivity in some polymer thin films

    Indian Academy of Sciences (India)

    M Ramakrishna Murthy; E Venkateshwar Rao

    2002-10-01

    Studies on the surface micromorphology and surface conductivity in thin polymer films of poly vinyl alcohol (PVA) and poly ethylene oxide (PEO) in both as-grown and ion-implanted polymer films have been carried out to reveal certain specific features of the ordered state in these materials. Optical microscopic investigations revealed the existence and enhanced formation in number of spherulites and dendrites in ionimplanted films relative to the as-grown films. The number and rate of formation of spherulites indicated an increase in the degree of crystallinity in these films. Measurements of surface conductivity of as-grown and ion-implanted polymer films, employing four-point probe method, indicated a decrease in electrical conductivity on ion-implantation. Photomicrographic analysis of the PVA and PEO thin film surfaces, has enabled to propose a temperature–stress induced mechanism of crystallization in conjunction with the surface conductivity measurements. The decrease in surface conductivity on ion-implantation in both PVA and PEO thin films, is attributed to a decrease in mobility of macromolecular charged species due to an increase in degree of crystallinity as has been observed by optical microscopy.

  1. Relating Film Structure/Microstructure on Device Function/Microproperties in Conjugated Polymers and Polymer/Small Molecule Blends

    Science.gov (United States)

    Cochran, Justin Enir

    Over the last twenty years conjugated organic materials, polymers and small molecules, have attracted broad interest due to their potential applications in the field of solution processed low cost electronics. Due to their semi/polycrystalline nature the spatial arrangement of crystallites and disordered regions in the film have a significant influence over charge transport properties. Structure-Function relationships are universal; consequently, the focus of my research thesis is to relate the film structure/microstructure to device performance and micro-properties, specifically in thin film transistors and bulk conductivity measurements. My initial research focus was on how modification of a semiconducting polymers backbone alters the packing structure and in turn impacts device performance. We then focused on how modification of TFT interface microstructures by altering between dielectric surfaces changes the orientaional correlation length in the semiconductors crystalline domains which in turn directly impacts the field effect mobility. The final two projects focused on doping conjugated polymers with small molecular acceptors. The purpose was to understand how bulk packing dominates conductivity in order to better understand what appears to be a universal transport behavior in these blends. These insights into the structural changes provide a platform under which to analyze the electrical measurements where significant changes in conductivity were observed at high acceptor concentrations but results showed dependence upon pre and post processing conditions. As expected, increases in film conductivity scaled with acceptor concentration but of special interest is how the conductivity showed temperature stability upon annealing, even increasing under certain conditions, near the polymer liquid crystal transition temperature and then decreasing below the as cast baseline at higher annealing temperatures. The electrical study combined with the structural analysis

  2. Formation of hybrid films from perylenediimide-labeled core-shell silica-polymer nanoparticles.

    Science.gov (United States)

    Ribeiro, Tânia; Fedorov, Aleksander; Baleizão, Carlos; Farinha, José Paulo S

    2013-07-01

    We prepared water-dispersible core-shell nanoparticles with a perylenediimide-labeled silica core and a poly(butyl methacrylate) shell, for application in photoactive high performance coatings. Films cast from water dispersions of the core-shell nanoparticles are flexible and transparent, featuring homogeneously dispersed silica nanoparticles, and exhibiting fluorescence under appropriate excitation. We characterized the film formation process using nanoparticles where the polymer shell has been labeled with either a non-fluorescent N-benzophenone derivative (NBen) or a fluorescent phenanthrene derivative (PheBMA). We used Förster resonance energy transfer (FRET) from PheBMA to NBen to follow the interparticle interdiffusion of the polymer anchored to the silica surface that occurs after the dried dispersions are annealing above the glass transition temperature of the polymer. By calculating the evolution of the FRET quantum efficiency with annealing time, we could estimate the approximate fraction of mixing (fm) between polymer from neighbor particles, and from this, the apparent diffusion coefficients (Dapp) for this process. For long annealing times, the limiting values of fm are slightly lower than for films of pure PBMA particles at similar temperatures (go up to 80% of total possible mixing). The corresponding diffusion coefficients are also very similar to those reported for films of pure PBMA, indicating that the fact that the polymer chains are anchored to the silica particles does not significantly hinder the diffusion process during the initial part of the mixing process. From the temperature dependence of the diffusion coefficients, we found an effective activation energy for diffusion of Ea=38 kcal/mol, very similar to the value obtained for particles of the same polymer without the silica core. With these results, we show that, although the polymer is grafted to the silica surface, polymer interdiffusion during film formation is not significantly

  3. Synthesis of novel electrically conducting polymers: Potential conducting Langmuir-Blodgett films and conducting polymers on defined surfaces

    Science.gov (United States)

    Zimmer, Hans

    1993-01-01

    Based on previous results involving thiophene derived electrically conducting polymers in which it was shown that thiophene, 3-substituted thiophenes, furans, and certain oligomers of these compounds showed electrical conductivity after polymerization. The conductivity was in the order of up to 500 S/cm. In addition, these polymers showed conductivity without being doped and most of all they were practically inert toward ambient conditions. They even could be used in aqueous media. With these findings as a guide, a number of 3-long-chain-substituted thiophenes and 1-substituted-3-long-chain substituted pyrrols were synthesized as monomers for potential polymeric electrically conducting Langmuir-Blodgett films.

  4. Directed Self-Assembly of Block Copolymers for High Breakdown Strength Polymer Film Capacitors

    Energy Technology Data Exchange (ETDEWEB)

    Samant, Saumil P.; Grabowski, Christopher A.; Kisslinger, Kim; Yager, Kevin G.; Yuan, Guangcui; Satija, Sushil K.; Durstock, Michael F.; Raghavan, Dharmaraj; Karim, Alamgir

    2016-03-04

    Emerging needs for fast charge/discharge yet high-power, lightweight, and flexible electronics requires the use of polymer-film-based solid-state capacitors with high energy densities. Fast charge/discharge rates of film capacitors on the order of microseconds are not achievable with slower charging conventional batteries, supercapacitors and related hybrid technologies. However, the current energy densities of polymer film capacitors fall short of rising demand, and could be significantly enhanced by increasing the breakdown strength (EBD) and dielectric permittivity (εr) of the polymer films. Co-extruded two-homopolymer component multilayered films have demonstrated much promise in this regard showing higher EBD over that of component polymers. Multilayered films can also help incorporate functional features besides energy storage, such as enhanced optical, mechanical, thermal and barrier properties. In this work, we report accomplishing multilayer, multicomponent block copolymer dielectric films (BCDF) with soft-shear driven highly oriented self-assembled lamellar diblock copolymers (BCP) as a novel application of this important class of self-assembling materials. Results of a model PS-b-PMMA system show ~50% enhancement in EBD of self-assembled multilayer lamellar BCP films compared to unordered as-cast films, indicating that the breakdown is highly sensitive to the nanostructure of the BCP. The enhancement in EBD is attributed to the “barrier effect”, where the multiple interfaces between the lamellae block components act as barriers to the dielectric breakdown through the film. The increase in EBD corresponds to more than doubling the energy storage capacity using a straightforward directed self-assembly strategy. This approach opens a new nanomaterial paradigm for designing high energy density dielectric materials.

  5. Synthesis and analysis of Fe3+, Co2+ and Ni2+ : PEO + PVP blended polymer composite films for multifunctional polymer applications

    Indian Academy of Sciences (India)

    K Naveen Kumar; M Vasudeva Reddy; L Vijayalakshmi; Y C Ratnakaram

    2015-08-01

    Blended polymer films of polyethylene oxide + polyvinyl pyrrolidone (PEO + PVP) containing transition metal (TM) ions like Fe3+, Co2+ and Ni2+ have been synthesized by a solution casting method. For these films, structural, thermal, magnetic and optical properties have been studied. X-ray diffraction results reveal the semi-crystalline nature of the polymer films. Thermal stability of the host (undoped) polymer film has been investigated from its thermogravimetric–differential thermal analysis profiles. Raman spectral profiles indicate a complex formation trend owing to the addition of TM ions into the host matrix. Co2+, Fe3+ and Ni2+ ions doped polymer films have revealed ferromagnetism based on their vibrating sample magnetometre profiles. However, the host polymer film has exhibited a paramagnetic nature. Further, ionic conductivities have been calculated using an impedance analyser at different temperatures for all the samples. Among these films, a maximum ionic conductivity ( = 7.5 × 10−6 S cm−1) has been noticed from PEO + PVP : Ni2+ polymer film at 373 K. Emission analysis of Co2+ : PEO + PVP polymer film has exhibited a strong red emission under an UV source and from both PEO + PVP : Fe3+; PEO + PVP: Ni2+, green emissions have commonly been noticed under an UV source. Thus, based on these results, it could be suggested that these TM ions doped PEO + PVP polymer films are found to be potential multifunctional materials for magneto-electric, magneto-optic fields with encouraging electrical, dielectric and optical properties as well as displaying with ferromagnetic nature from the doped films.

  6. Graphene Oxide-Polymer Composite Langmuir Films Constructed by Interfacial Thiol-Ene Photopolymerization

    Science.gov (United States)

    Luo, Xiaona; Ma, Kai; Jiao, Tifeng; Xing, Ruirui; Zhang, Lexin; Zhou, Jingxin; Li, Bingbing

    2017-02-01

    The effective synthesis and self-assembly of graphene oxide (GO) nanocomposites are of key importance for a broad range of nanomaterial applications. In this work, a one-step chemical strategy is presented to synthesize stable GO-polymer Langmuir composite films by interfacial thiol-ene photopolymerization at room temperature, without use of any crosslinking agents and stabilizing agents. It is discovered that photopolymerization reaction between thiol groups modified GO sheets and ene in polymer molecules is critically responsible for the formation of the composite Langmuir films. The film formed by Langmuir assembly of such GO-polymer composite films shows potential to improve the mechanical and chemical properties and promotes the design of various GO-based nanocomposites. Thus, the GO-polymer composite Langmuir films synthesized by interfacial thiol-ene photopolymerization with such a straightforward and clean manner, provide new alternatives for developing chemically modified GO-based hybrid self-assembled films and nanomaterials towards a range of soft matter and graphene applications.

  7. Photo-Induced Bending Behavior of Post-Crosslinked Liquid Crystalline Polymer/Polyurethane Blend Films.

    Science.gov (United States)

    Pang, Xinlei; Xu, Bo; Qing, Xin; Wei, Jia; Yu, Yanlei

    2017-06-30

    Photoresponsive blend films with post-crosslinked liquid crystalline polymer (CLCP) as a photosensitive component and flexible polyurethane (PU) as the matrix are successfully fabricated. After being uniaxially stretched, even at low concentration, the azobenzene-containing CLCP effectively transfers its photoresponsiveness to the photoinert PU matrix, resulting in the fast photo-induced bending behavior of whole blend film thanks to the effective dispersion of CLCP. Specifically, the blend film shows photo-induced deformations upon exposure to unpolarized UV light at ambient temperature. The film unbends after thermal treatment, and the randomly orientated mesogens in the film can be realigned by the mechanical stretching, which endows the film with a reversible deformation behavior. The photosensitive blend film possesses favorable mechanical property and good processability at low cost, and it is a promising candidate for a new generation of actuators. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Optical field-induced surface relief formation on chalcogenide and azo-benzene polymer films

    Science.gov (United States)

    Teteris, J.; Gertners, U.

    2012-08-01

    The dependence of the surface relief formation in amorphous As2S3 and Disperse Red 1dye grafted polyurethane polymer films on the polarization state of recording light was studied. It is shown that the direction of mass transport on the film surface is determined by the direction of light electric vector and photoinduced anisotropy in the film. We propose a photoinduced dielectropfhoretic model to explain the photoinduced mass transport in amorphous films. Model is based on the photoinduced softening of the matrix, formation of defects with enhanced or decreased polarizability, and their drift under the electrical field gradient of light.

  9. Field Emission Characteristics of Conducting Polymer Films Conditioned by Electric Discharge

    Institute of Scientific and Technical Information of China (English)

    Guohong LAI; Zhenglin LI; Lan CHENG; Junbiao PENG

    2006-01-01

    A pure conducting polymer(PANI-CSA)film conditioned by an electric discharge was tentatively utilized as an cathode for emitting electrons under electric fields. The emission of electrons was observed using a phosphor(ZnO:Zn)screen excited by electrons from the conditioned film. The film morphology was investigated using a scanning electron microscope and it was found that undulate whisker-like sites formed on the surface. The emission was presumably due to the undulate whisker-like sites. The field enhancement factor was estimated to be as high as 1150. The electron emitting process of the PANI-CSA film conditioned by electric discharge was also discussed.

  10. Structure-property relation in HPMC polymer films plasticized with Sorbitol

    Science.gov (United States)

    Prakash, Y.; Somashekarappa, H.; Mahadevaiah, Somashekar, R.

    2013-06-01

    A correlation study on physical and mechanical properties of Hydroxy propyl-methylcellulose (HPMC) polymer films plasticized with different weight ratio of Sorbitol, prepared using solution casting method, was carried out using wide angle X-ray technique and universal testing machine. It is found that the crystallanity decreases as the concentration of Sorbitol increases up to a certain concentration and there afterwards increases. Measured Physical Properties like tensile strength decreases and elongation (%) increases indicating increase in the flexibility of the films. These observations confirm the correlation between microstructal parameters and mechanical properties of films. These films are suitable for packaging food products.

  11. Critical Material Attributes of Strip Films Loaded With Poorly Water-Soluble Drug Nanoparticles: II. Impact of Polymer Molecular Weight.

    Science.gov (United States)

    Krull, Scott M; Ammirata, Jennifer; Bawa, Sonia; Li, Meng; Bilgili, Ecevit; Davé, Rajesh N

    2017-02-01

    Recent work established polymer strip films as a robust platform for delivery of poorly water-soluble drug particles. However, a simple means of manipulating rate of drug release from films with minimal impact on film mechanical properties has yet to be demonstrated. This study explores the impact of film-forming polymer molecular weight (MW) and concentration on properties of polymer films loaded with poorly water-soluble drug nanoparticles. Nanoparticles of griseofulvin, a model Biopharmaceutics Classification System class II drug, were prepared in aqueous suspension via wet stirred media milling. Aqueous solutions of 3 viscosity grades of hydroxypropyl methylcellulose (14, 21, and 88 kDa) at 3 viscosity levels (∼9500, ∼12,000, and ∼22,000 cP) were mixed with drug suspension, cast, and dried to produce films containing griseofulvin nanoparticles. Few differences in film tensile strength or elongation at break were observed between films within each viscosity level regardless of polymer MW despite requiring up to double the time to achieve 100% drug release. This suggests film-forming polymer MW can be used to manipulate drug release with little impact on film mechanical properties by matching polymer solution viscosity. In addition, changing polymer MW and concentration had no negative impact on drug content uniformity or nanoparticle redispersibility.

  12. Photonic effects in microstructured conjugated polymer films and light emitting diodes

    CERN Document Server

    Matterson, B J

    2002-01-01

    metal layers that are used as electrodes in the LED does not adversely affect the electrical properties of the LED. It is demonstrated that grating in the LED is able to substantially increase the light emission without using extra electrical power. The emission spectra from LEDs are observed to vary with angle, and exhibit considerable polarization. This thesis reports an investigation into the photonic effects caused by wavelength scale microstructure patterned onto films of conjugated polymers. The efficiency of light emitting diodes (LEDs) made from conjugated polymers is limited in part by the trapping of light into waveguide modes caused by the high refractive index of these materials. Waveguide modes in films of poly(p,-phenylene vinylene) (PPV) and poly(2-methoxy, 5-(2'ethylhexyloxy)-p-phenylene vinylene) (MEH-PPV) are analysed and the refractive index of these materials is calculated. The photoluminescence of conjugated polymer films that have been spun onto textured substrates is analysed. It is fou...

  13. Azaisoindigo conjugated polymers for high performance n-type and ambipolar thin film transistor applications

    KAUST Repository

    Yue, Wan

    2016-09-28

    Two new alternating copolymers, PAIIDBT and PAIIDSe have been prepared by incorporating a highly electron deficient azaisoindigo core. The molecular structure and packing of the monomer is determined from the single crystal X-ray diffraction. Both polymers exhibit high EAs and highly planar polymer backbones. When polymers are used as the semiconducting channel for solution-processed thin film transistor application, good properties are observed. A–A type PAIIDBT exhibits unipolar electron mobility as high as 1.0 cm2 V−1 s−1, D–A type PAIIDSe exhibits ambipolar charge transport behavior with predominately electron mobility up to 0.5 cm2 V−1 s−1 and hole mobility to 0.2 cm2 V−1 s−1. The robustness of the extracted mobility values are also commented on in detail. Molecular orientation, thin film morphology and energetic disorder of both polymers are systematically investigated.

  14. Colour electroluminescence with end light-emitting from ZnO nanowire/polymer film

    Energy Technology Data Exchange (ETDEWEB)

    He Ying; Wang Junan [Institute of Materials, School of Materials Science and Engineering, Shanghai University, Shanghai 200072 (China); Zhang Wenfei; Chen Xiaoban; Huang Zonghao; Gu Qiuwen [Department of Polymer Materials, School of Materials Science and Engineering, Shanghai University, 149 Yanchang Road, Shanghai 200072 (China)], E-mail: yinghe@staff.shu.edu.cn

    2009-03-01

    The ZnO nanowires with polymer film were self-assembly grown on n-type (111) plane of the silicon substrate using polymer assisted complexing soft-template process through a simple polymer complexation and low-temperature oxidizing-sintering, which have smooth top and fine hexagonal columnar structure with average length of about 6 {mu}m and the diameter of about 40 nm. These columnar structured ZnO nanowires had strong near-band ultraviolet emission at {approx}383 nm and blue electrically driven emission at {approx} 400 nm with a relatively low turn-on voltage, as well as a typical diode characteristic property at room temperature. In particular, these structures, being of high aspect ratio and small tip radius of curvature, may possess a good amplified stimulated emission and lasing property. These results suggested a potential application of ZnO nanowire/polymer film as electroluminescence flat panel displays or illuminations in the future.

  15. Zinc-Based Semiconductors/Polymer Thin Films Junction for Photovoltaic Application

    Directory of Open Access Journals (Sweden)

    Souad Al-bat’hi

    2012-01-01

    Full Text Available Thin films of ZnO and ZnTe semiconductors were deposited on ITO conducting glass substrates by sputtering and electrodeposition techniques, respectively. On the other hand, thin films of ion conducting solid polymer electrolyte were prepared by solution cast technique. The polymer is a blend of 50 wt% polyethylene oxide and 50 wt% chitosan. To provide redox couple (I−/I3−, the polymer was complexed with ammonium iodide NH4I with addition of few crystals of iodine I2. Ammonium iodide NH4I was added to the solution in different amounts (wt% weight ratios to supply the charge carriers for the polymer electrolytes. The highest ionic conductivity of the polymer electrolyte was 1.18×10−5 S cm−1 at room temperature. Structural and optical properties of the semiconductor thin films were characterized by X-ray diffractometer and UV-Vis spectrophotometer. The XRD shows crystalline structures for both ZnO and ZnTe thin films. The UV-Vis shows direct energy gaps EZnO of 3.1 eV and EZnTe of 2.2 eV. The polymer film was sandwiched between the ZnO and ZnTe semiconductors to form ITO/ZnO/polymer/ZnTe/ITO double-junction photovoltaic cell, and the photovoltaic properties were studied. The highest open-circuit voltage oc, short-circuit current density sc, and fill factor FF of the fabricated cells are 0.5 V, 55 μA cm−2, and 27%, respectively.

  16. Thin films of metal-organic compounds and metal nanoparticle-embedded polymers for nonlinear optical applications

    Indian Academy of Sciences (India)

    S Philip Anthony; Shatabdi Porel; D Narayana Rao; T P Radhakrishnan

    2005-11-01

    Thin films based on two very different metal-organic systems are developed and some nonlinear optical applications are explored. A family of zinc complexes which form perfectly polar assemblies in their crystalline state are found to organize as uniaxially oriented crystallites in vapor deposited thin films on glass substrate. Optical second harmonic generation from these films is investigated. A simple protocol is developed for the in-situ fabrication of highly monodisperse silver nanoparticles in a polymer film matrix. The methodology can be used to produce free-standing films. Optical limiting capability of the nanoparticle-embedded polymer film is demonstrated.

  17. Characterization of Thin Films for Polymer Solar Cells

    DEFF Research Database (Denmark)

    Tromholt, Thomas

    The field of polymer solar cells has undergone an extensive development in recent years after the invention of semiconducting polymers in 1991. Efficiencies have gradually increased to above 10 %, and high throughput processing methods such as roll-to-roll coating allow for production of thousands...... of solar cells with low embedded time, material, and energy consumption as compared to silicon solar cells. Consequently, different demonstration products of small mobile gadgets based on polymer solar cells have been produced, which are fully competitive with conventional energy technologies, illustrating...... process where oxygen and water diffusion from the atmosphere, morphology evolution, and photo-bleaching of the polymer are some of the dominant processes. Encapsulation by foils consisting of multi-layer polymer stacks is a conventional way to reduce the diffusion into the solar cell, by which the life...

  18. Geometry Control of Photo-induced Microstructures in an Azobenzene Polymer Film

    Institute of Scientific and Technical Information of China (English)

    Xu Ze-Da; LI Zhen; LIANG Li-Zhen; PENG Zhuo-Lun; CAI Zhi-Gang; ZHOU Jian-Ying; NINULESCU Valerica; ZHANG Ling-Zhi

    2001-01-01

    The mechanisms of photo-induced microstructures in an azobenzene polymer film are presented. They are based on the spatial periodic modulation of optical intensity and the photoisomerization of azobenzene molecules with the movement of main chains. Experiment and theory jointly point out the possibility of photo-inducing desired spatial microstructures in an azobenzene organic polymer via adequate optical lattices and adequately polarized ‘writing' beams.

  19. PREPARATION OF PHOTOFUNCTIONAL POLYMER THIN FILMS BY LANGMUIR-BLODGETT TECHNIQUE

    Institute of Scientific and Technical Information of China (English)

    Tokuji Miyashita; Tatsuo Taniguchi; Yoshihito Fukasawa

    1999-01-01

    Polymer LB films containing photofuntional groups were prepared by the copolymerization of N-dodecylacrylamide (DDA), which has an excellent property to form a stable monolayer and LB multilayers with photofunctional monomers. Tris(2, 2'-bipyridine) ruthenium complex, Ru(bpy)32+, one of the most wellknown redox-active sensitizer, was incorporated into the DDA copolymer. The photogalvanic effect based on the photoinduced electron transfer using the ruthenium complex in the polymer LB monolayer was discussed.

  20. A TEMPERATURE AND pH DOUBLE SENSITIVE CHOLESTERIC POLYMER FILM FROM A PHOTOPOLYMERIZABLE CHIRAL HYDROGEN-BONDED ASSEMBLY

    Institute of Scientific and Technical Information of China (English)

    Feng-jin Chen; Jin-bao Guo; Ou-yu Jin; Jie Wei

    2013-01-01

    In this study,a novel H-bonded cholesteric polymer film responding to temperature and pH by changing the reflection color was fabricated.The H-bonded cholesteric polymer film was achieved by UV-photopolymerizing a cholesteric liquid crystal (Ch-LC) monomers mixture containing a photopolymerizable chiral H-bonded assembly (PCHA).The cholesteric polymer film based on PCHA can be thermally switched to reflect red color from the initial green/yellow color as temperature is increased,which is due to a change in helical pitch induced by the weakening of H-bonded interaction in the polymer film.Additionally,the selective reflection band (SRB) of the cholesteric polymer film in solution with pH > 7showed an obvious red shift with increasing pH values.While the SRB of the cholesteric polymer film in solutions with pH =7 and pH < 7 hardly changed.This pH sensitivity in solutions with pH > 7 could be explained by the breakage of H-bonds in the cholesteric polymer film and the structure changes induced by-OFF and-K+ ions in the alkaline solution.In contrast,it couldn't happen in the neutral and acidic solutions.The cholesteric polymer film in this study can be used as optical/photonic papers,optical sensors and LCs displays,etc.

  1. An optical reflected device using a molecularly imprinted polymer film sensor

    Energy Technology Data Exchange (ETDEWEB)

    Wu Nan; Feng Liang; Tan Yiyong [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China); Hu Jiming, E-mail: jmhu@whu.edu.cn [College of Chemistry and Molecular Sciences, Wuhan University, Wuhan 430072 (China)

    2009-10-19

    A novel and highly selective optical sensor with molecularly imprinted polymer (MIP) film was fabricated and investigated. The optical sensor head employing a medium finesse molecularly imprinted polymer film has been fabricated and characterised. A blank polymer and formaldehyde imprinted polymer were using methacrylic acid as the functional monomer and the ethylene glycol dimethacrylate as a crosslinker. The transduction mechanism is discussed based on the changes of optical intensity of molecularly imprinted polymer film acting as an optical reflected sensor. Template molecules, which diffused into MIP, could cause film density, and refractive index change, and then induce measurable optical reflective intensity shifts. Based on the reflective intensity shifts, an optical reflection detection of formaldehyde was achieved by illuminating MIP with a laser beam. For the same MIP, the reflective intensity shift was proportional to the amount of template molecule. This optical sensor, based on an artificial recognition system, demonstrates long-time stability and resistance to harsh chemical environments. As the research moves forward gradually, we establish the possibilities of quantitative analysis primly, setting the groundwork to the synthesis of the molecular imprinted optical fiber sensor. The techniques show good reproducibility and sensitivity and will be of significant interest to the MIPcommunity.

  2. Reversible electric field induced spectral hole filling in a doped polymer film

    Science.gov (United States)

    Gu, Wei; Hanson, David M.

    1988-09-01

    The effect of a dc electric field on persistent spectral holes in the absorption spectra of perylene doped polyvinyl butyral films has been measured. This effect is not like a typical Stark effect that is obtained with polymer films doped with polar dye molecules. Instead, a new phenomenon of reversible spectral hole filling is observed. This phenomenon is attributed to the elastic deformation of the interaction potentials of the dopant and the polymer associated with reversible field-induced tunneling in the intrinsic two-level systems. A quantitative theory of the phenomenon is proposed.

  3. Ultraviolet and infrared femtosecond laser induced periodic surface structures on thin polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Rebollar, Esther; Castillejo, Marta [Instituto de Quimica Fisica Rocasolano, CSIC, Serrano 119, 28006 Madrid (Spain); Vazquez de Aldana, Javier R.; Moreno, Pablo [Grupo de Investigacion en Microprocesado de Materiales con Laser, Universidad de Salamanca, Plaza de la Merced s/n, 37008 Salamanca (Spain); Perez-Hernandez, Jose A. [Centro de Laseres Pulsados Ultracortos Ultraintensos, CLPU, Plaza de la Merced s/n, 37008 Salamanca (Spain); Ezquerra, Tiberio A. [Instituto de Estructura de la Materia, IEM-CSIC, Serrano 121, 28006 Madrid (Spain)

    2012-01-23

    This work demonstrates the formation of femtosecond laser induced periodic surface structures (LIPSS) by multipulse irradiation with the fundamental and 3rd harmonic of a linearly polarized Ti:sapphire laser (795 and 265 nm) on thin films of the polymers poly (ethylene terephthalate), poly (trimethylene terephthalate), and poly (carbonate bisphenol A) prepared by spin-coating. LIPSS, inspected by atomic force microscopy, are formed upon multiple pulse UV and IR irradiation with wavelength-sized period in a narrow range of fluences below the ablation threshold. Control and tunability of the size and morphology of the periodic structures become thus possible ensuring photochemical integrity of polymer films.

  4. Ultrafast formation of air-processable and high-quality polymer films on an aqueous substrate

    Science.gov (United States)

    Noh, Jonghyeon; Jeong, Seonju; Lee, Jung-Yong

    2016-08-01

    Polymer solar cells are attracting attention as next-generation energy sources. Scalable deposition techniques of high-quality organic films should be guaranteed to realize highly efficient polymer solar cells in large areas for commercial viability. Herein, we introduce an ultrafast, scalable, and versatile process for forming high-quality organic films on an aqueous substrate by utilizing the spontaneous spreading phenomenon. This approach provides easy control over the thickness of the films by tuning the spreading conditions, and the films can be transferred to a variety of secondary substrates. Moreover, the controlled Marangoni flow and ultrafast removal of solvent during the process cause the films to have a uniform, high-quality nanomorphology with finely separated phase domains. Polymer solar cells were fabricated from a mixture of polymer and fullerene derivatives on an aqueous substrate by using the proposed technique, and the device exhibited an excellent power conversion efficiency of 8.44 %. Furthermore, a roll-to-roll production system was proposed as an air-processable and scalable commercial process for fabricating organic devices.

  5. Localized etching of polymer films using an atmospheric pressure air microplasma jet

    Science.gov (United States)

    Guo, Honglei; Liu, Jingquan; Yang, Bin; Chen, Xiang; Yang, Chunsheng

    2015-01-01

    A direct-write process device based on the atmospheric pressure air microplasma jet (AμPJ) has been developed for the localized etching of polymer films. The plasma was generated by the air discharge ejected out through a tip-nozzle (inner diameter of 100 μm), forming the microplasma jet. The AμPJ was capable of reacting with the polymer surface since it contains a high concentration of oxygen reactive species and thus resulted in the selective removal of polymer films. The experimental results demonstrated that the AμPJ could fabricate different microstructures on a parylene-C film without using any masks or causing any heat damage. The etch rate of parylene-C reached 5.1 μm min-1 and microstructures of different depth and width could also be realized by controlling two process parameters, namely, the etching time and the distance between the nozzle and the substrate. In addition, combining XPS analysis and oxygen-induced chemical etching principles, the potential etching mechanism of parylene-C by the AμPJ was investigated. Aside from the etching of parylene-C, micro-holes on the photoresist and polyimide film were successfully created by the AμPJ. In summary, maskless pattern etching of polymer films could be achieved using this AμPJ.

  6. Assembly of poly(dopamine) films mixed with a nonionic polymer.

    Science.gov (United States)

    Zhang, Yan; Thingholm, Bo; Goldie, Kenneth N; Ogaki, Ryosuke; Städler, Brigitte

    2012-12-21

    Poly(dopamine) (PDA) coatings have recently attracted considerable interest for a variety of applications. Here, we investigate the film deposition of dopamine mixed with a nonionic polymer (i.e., poly(ethylene glycol) (PEG), poly(vinyl alcohol) (PVA), and poly(N-vinyl pyrrolidone) (PVP)) onto silica substrates using X-ray photoelectron spectroscopy and quartz crystal microbalance. Furthermore, we assess the possibility of coating silica colloids to yield polymer capsules and liposomes with these mixtures. We found that mixed PDA/PEG and PDA/PVA films are deposited without the need for a covalent linker such as an amine or thiol. We also discovered the first material, namely, PVP, that can suppress PDA film assembly. These fundamental findings give further insight into PDA film properties and contribute to establish PDA as a widely applicable coating.

  7. Self-destruction and dewetting of thin polymer films the role of interfacial tensions

    CERN Document Server

    Reiter, G; Sharma, A

    2003-01-01

    We present real-time optical microscopy observations of the pattern evolution in self-destruction and subsequent dewetting of thin polymer films based on experiments with polydimethylsiloxane films sandwiched between silicon wafers and aqueous surfactant solutions. A clear scenario consisting of four distinct stages has been identified: amplification of surface fluctuations, break-up of the film and formation of holes, growth and coalescence of holes, and droplet formation and ripening. Besides a linear dependence on film viscosity and surface tension, the time tau for film rupture varied significantly with film thickness h (tau approx h sup 5), as expected from theory. While the role of long-range forces is dominant only in the first stage, the later stages are controlled by the combination of interfacial tensions resulting in the contact angle characterizing the three-phase contact line. During the first stage, the characteristic distance of the pattern remains constant, represented by a time-independent wa...

  8. Surface characteristics of a self-polymerized dopamine coating deposited on hydrophobic polymer films.

    Science.gov (United States)

    Jiang, Jinhong; Zhu, Liping; Zhu, Lijing; Zhu, Baoku; Xu, Youyi

    2011-12-06

    This study aims to explore the fundamental surface characteristics of polydopamine (pDA)-coated hydrophobic polymer films. A poly(vinylidene fluoride) (PVDF) film was surface modified by dip coating in an aqueous solution of dopamine on the basis of its self-polymerization and strong adhesion feature. The self-polymerization and deposition rates of dopamine on film surfaces increased with increasing temperature as evaluated by both spectroscopic ellipsometry and scanning electronic microscopy (SEM). Changes in the surface morphologies of pDA-coated films as well as the size and shape of pDA particles in the solution were also investigated by SEM, atomic force microscopy (AFM), and transmission electron microscopy (TEM). The surface roughness and surface free energy of pDA-modified films were mainly affected by the reaction temperature and showed only a slight dependence on the reaction time and concentration of the dopamine solution. Additionally, three other typical hydrophobic polymer films of polytetrafluoroethylene (PTFE), poly(ethylene terephthalate) (PET), and polyimide (PI) were also modified by the same procedure. The lyophilicity (liquid affinity) and surface free energy of these polymer films were enhanced significantly after being coated with pDA, as were those of PVDF films. It is indicated that the deposition behavior of pDA is not strongly dependent on the nature of the substrates. This information provides us with not only a better understanding of biologically inspired surface chemistry for pDA coatings but also effective strategies for exploiting the properties of dopamine to create novel functional polymer materials.

  9. X-ray scattering from freestanding polymer films with geometrically curved surfaces

    OpenAIRE

    D.J. Lee; K. Shin; Seeck, O; Kim, H.; Seo, Y.-S.; Tolan, M.; Rafailovich, M. H.; Sokolov, J.; Sinha, S.K.

    2003-01-01

    We show that the x-ray surface scattering from a freestanding polymer film exhibits features that cannot be explained by the usual stochastic formalism for surfaces with random height fluctuations. Instead, a geometric description of the film morphology assuming two curved surfaces characterized by a radius of curvature and a lateral cutoff length successfully accounts for the phase difference between the Kiessig fringes of the nominal "specular" and "off-specular" components of the scatterin...

  10. Different strategies to improve the functionality of biodegradable films based on starch and other polymers

    OpenAIRE

    2016-01-01

    [EN] In the present Doctoral Thesis, different strategies to improve functional properties of starch films for food packaging applications were analysed: study of the effect of amylose:amylopectin ratio, blend with other polymers poly(vinyl alcohol) (PVA), and incorporation of different fillers (rice bran and cellulose nanocrystals-CNCs) and antimicrobial agents (neem oil-N, oregano essential oil-O and silver nanoparticles-AgNPs). Likewise, a biodegradation study of the films as affected by a...

  11. Positron Annihilation Spectroscopy of High Performance Polymer Films under CO2 Pressure

    Energy Technology Data Exchange (ETDEWEB)

    C.A. Quarles; John R. Klaehn; Eric S. Peterson; Jagoda M. Urban-Klaehn

    2010-08-01

    Positron annihilation Lifetime and Doppler broadening measurements are reported for six polymer films as a function of carbon dioxide absolute pressure ranging from 0 to 45 psi. Since the polymer films were thin and did not absorb all positrons, corrections were made in the lifetime analysis for the absorption of positrons in the positron source and sample holder using the Monte Carlo transport code MCNP. Different polymers are found to behave differently. Some polymers studied form positronium and some, such as the polyimide structures, do not. For those samples that form positronium an interpretation in terms of free volume is possible; for those that don’t form positronium, further work is needed to determine how best to describe the behavior in terms of the bulk positron annihilation parameters. Some polymers exhibit changes in positron lifetime and intensity under CO2 pressure which may be described by the Henry or Langmuir sorption models, while the positron response of other polymers is rather insensitive to the CO2 pressure. The results demonstrate the usefulness of positron annihilation spectroscopy in investigating the sorption of CO2 into various polymers at pressures up to about 3 atm.

  12. Effect of interface on surface morphology and proton conduction of polymer electrolyte thin films.

    Science.gov (United States)

    Ohira, Akihiro; Kuroda, Seiichi; Mohamed, Hamdy F M; Tavernier, Bruno

    2013-07-21

    To understand the relationship between surface morphology and proton conduction of polymer electrolyte thin films, perfluorinated ionomer Nafion® thin films were prepared on different substrates such as glassy carbon (GC), hydrophilic-GC (H-GC), and platinum (Pt) as models for the ionomer film within a catalyst layer. Atomic force microscopy coupled with an electrochemical (e-AFM) technique revealed that proton conduction decreased with film thickness; an abrupt decrease in proton conductance was observed when the film thickness was less than ca. 10 nm on GC substrates in addition to a significant change in surface morphology. Furthermore, thin films prepared on H-GC substrates with UV-ozone treatment exhibited higher proton conduction than those on untreated GC substrates. However, Pt substrates exhibited proton conduction comparable to that of GCs for films thicker than 20 nm; a decrease in proton conduction was observed at ∼5 nm thick film but was still much higher than for carbon substrates. These results indicate that the number of active proton-conductive pathways and/or the connectivity of the proton path network changed with film thickness. The surface morphology of thinner films was significantly affected by the film/substrate interface and was fundamentally different from that of the bulk thick membrane.

  13. Flexible fluidic microchips based on thermoformed and locally modified thin polymer films.

    Science.gov (United States)

    Truckenmüller, R; Giselbrecht, S; van Blitterswijk, C; Dambrowsky, N; Gottwald, E; Mappes, T; Rolletschek, A; Saile, V; Trautmann, C; Weibezahn, K-F; Welle, A

    2008-09-01

    This paper presents a fundamentally new approach for the manufacturing and the possible applications of lab on a chip devices, mainly in the form of disposable fluidic microchips for life sciences applications. The new technology approach is based on a novel microscale thermoforming of thin polymer films as core process. The flexibility not only of the semi-finished but partly also of the finished products in the form of film chips could enable future reel to reel processes in production but also in application. The central so-called 'microthermoforming' process can be surrounded by pairs of associated pre- and postprocesses for micro- and nanopatterned surface and bulk modification or functionalisation of the formed films. This new approach of microscale thermoforming of thin polymer film substrates overlaid with a split local modification of the films is called 'SMART', which stands for 'substrate modification and replication by thermoforming'. In the process, still on the unformed, plane film, the material modifications of the preprocess define the locations where later, then on the spatially formed film, the postprocess generates the final local modifications. So, one can obtain highly resolved modification patterns also on hardly accessible side walls and even behind undercuts. As a first application of the new technology, we present a flexible chip-sized scaffold for three dimensional cell cultivation in the form of a microcontainer array. The spatially warped container walls have been provided with micropores, cell adhesion micropatterns and thin film microelectrodes.

  14. Enhanced dielectric performance in polymer composite films with carbon nanotube-reduced graphene oxide hybrid filler.

    Science.gov (United States)

    Kim, Jin-Young; Kim, TaeYoung; Suk, Ji Won; Chou, Harry; Jang, Ji-Hoon; Lee, Jong Ho; Kholmanov, Iskandar N; Akinwande, Deji; Ruoff, Rodney S

    2014-08-27

    The electrical conductivity and the specific surface area of conductive fillers in conductor-insulator composite films can drastically improve the dielectric performance of those films through changing their polarization density by interfacial polarization. We have made a polymer composite film with a hybrid conductive filler material made of carbon nanotubes grown onto reduced graphene oxide platelets (rG-O/CNT). We report the effect of the rG-O/CNT hybrid filler on the dielectric performance of the composite film. The composite film had a dielectric constant of 32 with a dielectric loss of 0.051 at 0.062 wt% rG-O/CNT filler and 100 Hz, while the neat polymer film gave a dielectric constant of 15 with a dielectric loss of 0.036. This is attributed to the increased electrical conductivity and specific surface area of the rG-O/CNT hybrid filler, which results in an increase in interfacial polarization density between the hybrid filler and the polymer.

  15. Clay platelet partition within polymer blend nanocomposite films by EFTEM.

    Science.gov (United States)

    Linares, Elisângela M; Rippel, Márcia M; Galembeck, Fernando

    2010-12-01

    Transmission electron microscopy (TEM) is the main technique used to investigate the spatial distribution of clay platelets in polymer nanocomposites, but it has not often been successfully used in polymer blend nanocomposites because the high contrast between polymer phases impairs the observation of clay platelets. This work shows that electron spectral imaging in energy-filtered TEM (EFTEM) in the low-energy-loss spectral crossover region allows the observation of platelets on a clear background. Separate polymer domains are discerned by imaging at different energy losses, above and below the crossover energy, revealing the material morphology. Three blends (natural rubber [NR]/poly(styrene-butyl acrylate) [P(S-BA)], P(S-BA)/poly(vinyl chloride) [PVC], and NR/starch) were studied in this work, showing low contrast between the polymer phases in the 40-60 eV range. In the NR/P(S-BA) and P(S-BA)/PVC blend nanocomposites, the clay platelets accumulate in the P(S-BA) phase, while in the P(S-BA)/PVC nanocomposites, clay is also found at the interfaces. In the NR/starch blend, clay concentrates at the interface, but it also penetrates the two polymer phases. These observations reveal that nanostructured soft materials can display complex morphochemical patterns that are discerned thanks to the ability of EFTEM to produce many contrast patterns for the same sample.

  16. Three dimensional phase field study on the thickness effect of ferroelectric polymer thin film

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The electromechanical behavior of poly(vinylidene fluoride-trifluoroethylene)[P(VDF -TrFE)]ferroelectric thin film was investigated using the three dimensional(3D) phase-field method. Various energetic contributions,including elastic,electrostatic,and domain wall energy were taken into account in the variational functional of the phase field model.Evolution of the microscopic domain structures of P(VDF-TrFE) polymer film was simulated.Effects of the in-plane residual stress,the film thickness and externa...

  17. Fourier transform infrared spectroscopy for irradiation coumarin doped polystyrene polymer films by alpha ray

    Directory of Open Access Journals (Sweden)

    Mahasin F. Hadi Al-Kadhemy

    2016-07-01

    Full Text Available FTIR spectroscopy has been in use broadly to study microscopic areas in polymers for the last years. The FTIR transmission spectra of coumarin laser dye, polystyrene and coumarin doped polystyrene films with different doping ratio of coumarin solution have been studied. These spectra measured and explained for all films before and after Alpha irradiation with different irradiation times. All samples prepared by casting method. FTIR corroborate chemical bonds of coumarin dye molecules and polystyrene films by producing an IR absorption spectrum when increasing doping ratio of coumarin solution and when irradiation by Alpha source. There are some bonds disappeared after irradiation.

  18. Influence of plasma discharge on the structure of polytetrafluoroethylene film and step coverage on polymer substrate

    Energy Technology Data Exchange (ETDEWEB)

    Grytsenko, K.P. [Institute of Semiconductor Physics, 45 Nauki pr., Kyiv, 03028 (Ukraine); Institute of Photonics, Laser and Plasma Technology, University of Applied Sciences Wildau, F.-Engels-Str. 63, 15745, Wildau (Germany)], E-mail: d_gryts@isp.kiev.ua; Lytvyn, P.M. [Institute of Semiconductor Physics, 45 Nauki pr., Kyiv, 03028 (Ukraine); Friedrich, J.; Schulze, R.D. [Federal Institute for Materials Research and Testing (BAM), Unter den Eichen 87, 12205 Berlin (Germany); Schrader, S. [Institute of Photonics, Laser and Plasma Technology, University of Applied Sciences Wildau, F.-Engels-Str. 63, 15745, Wildau (Germany)

    2007-09-15

    Polytetrafluoroethylene (PTFE) films have been deposited onto polycarbonate (PC) substrates from the products of PTFE evaporation, activated by a cloud of accelerated electrons. A 40.68 MHz glow discharge was used during the deposition process. The polymer films have been characterised by XPS, FTIR and AFM. The use of the low power plasma during film growth led to the formation of PTFE films with modified structure. Films are amorphous and contain more cross-links, but in general, the structure of their macromolecules is still linear. An increase of RF-power leads to the formation of films with large amount of double bonds and enhanced internal stresses. Deposition of PTFE on PC without plasma treatment led to the formation of PTFE clusters up to 50 nm in diameter. The RMS roughness of the films, deposited without plasma, was about 4 nm, while the films deposited with plasma treatment had a roughness of 1.5 nm. The use of plasma has an additional effect if a PTFE coating is deposited on the PC substrate with submicrometer-sized steps. Without plasma the steps retain a rectangular shape. Deposited with the RF-discharge the PTFE layers resemble plasma-polymerised films. Under certain conditions the deposited films can fill trenches in the substrate like a wetting liquid, while under other conditions they avoid trenches and grow in between them.

  19. Solvation Dependent Redox-Gated Fluorescence Emission in a Diarylethene-Based Sexithiophene Polymer Film

    NARCIS (Netherlands)

    Kortekaas, Luuk; Browne, Wesley R.

    2016-01-01

    Bringing the functionality of molecular systems to interfaces while avoiding cross-talk and loss of function is essential to realize their full potential. The photochromic and -physical properties in polymer films formed from a terthiophene-diarylethene bifunctional monomer are lost due to aggregati

  20. Research on the electronic and optical properties of polymer and other organic molecular thin films

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-02-01

    The main goal of the work is to find materials and methods of optimization of organic layered electroluminescent cells and to study such properties of polymers and other organic materials that can be used in various opto-electronic devices. The summary of results obtained during the first year of work is presented. They are: (1) the possibility to produce electroluminescent cells using a vacuum deposition photoresist technology for commercial photoresists has been demonstrated; (2) the idea to replace the polyaryl polymers by other polymers with weaker hole conductivity for optimization of electroluminescent cells with ITO-Al electrodes has been suggested. The goal is to obtain amorphous processable thin films of radiative recombination layers in electroluminescent devices; (3) procedures of preparation of high-quality vacuum-deposited poly (p-phenylene) (PPP) films on various substrates have been developed; (4) it was found for the first time that the fluorescence intensity of PPP films depends on the degree of polymerization; (5) the role of interfaces between organic compounds, on one side, and metals or semiconductors, on the other side, has been studied and quenching of the fluorescence caused by semiconductor layer in thin sandwiches has been observed; (6) studies of the dynamics of photoexcitations revealed the exciton self-trapping in quasi-one-dimensional aggregates; and (7) conditions for preparation of highly crystalline fullerene C{sub 60} films by vacuum deposition have been found. Composites of C{sub 60} with conjugated polymers have been prepared.

  1. A simple two-step method to fabricate highly transparent ITO/polymer nanocomposite films

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Haitao [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Zeng, Xiaofei, E-mail: zengxf@mail.buct.edu.cn [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Kong, Xiangrong [State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029 (China); Bian, Shuguang [The High Technology Research and Development Center, The Ministry of Science and Technology, Beijing 100044 (China); Chen, Jianfeng [Research Center of the Ministry of Education for High Gravity Engineering and Technology, Beijing University of Chemical Technology, Beijing 100029 (China)

    2012-09-01

    Highlights: Black-Right-Pointing-Pointer A simple two-step method without further surface modification step was employed. Black-Right-Pointing-Pointer ITO nanoparticles were easily to be uniformly dispersed in polymer matrix. Black-Right-Pointing-Pointer ITO/polymer nanocomposite film had high transparency and UV/IR blocking properties. - Abstract: Transparent functional indium tin oxide (ITO)/polymer nanocomposite films were fabricated via a simple approach with two steps. Firstly, the functional monodisperse ITO nanoparticles were synthesized via a facile nonaqueous solvothermal method using bifunctional chemical agent (N-methyl-pyrrolidone, NMP) as the reaction solvent and surface modifier. Secondly, the ITO/acrylics polyurethane (PUA) nanocomposite films were fabricated by a simple sol-solution mixing method without any further surface modification step as often employed traditionally. Flower-like ITO nanoclusters with about 45 nm in diameter were mono-dispersed in ethyl acetate and each nanocluster was assembled by nearly spherical nanoparticles with primary size of 7-9 nm in diameter. The ITO nanoclusters exhibited an excellent dispersibility in polymer matrix of PUA, remaining their original size without any further agglomeration. When the loading content of ITO nanoclusters reached to 5 wt%, the transparent functional nanocomposite film featured a high transparency more than 85% in the visible light region (at 550 nm), meanwhile cutting off near-infrared radiation about 50% at 1500 nm and blocking UV ray about 45% at 350 nm. It could be potential for transparent functional coating materials applications.

  2. Static and kinetic friction of strongly confined polymer films under shear

    NARCIS (Netherlands)

    Hirz, S; Subbotin, A; Frank, C; Hadziioannou, G

    1996-01-01

    In the present work, we investigate the dependence of relaxational processes in strongly confined polymer liquids as a function of the molecular mass and of the confining film thickness, both theoretically and experimentally. A qualitative agreement is observed between the theoretical predictions an

  3. Gas Permeation Related to the Moisture Sorption in Films of Glassy Hydrophilic Polymers

    NARCIS (Netherlands)

    Laksmana, F. L.; Kok, P. J. A. Hartman; Frijlink, H. W.; Vromans, H.; Maarschalk, K. Van Der Voort

    2010-01-01

    The purpose of this article is to elucidate the effect of integral sorption of moisture on gas permeation in glassy hydrophilic polymers. The oxygen and the simultaneous moisture sorption into various hydroxypropyl methylcellulose (HPMC) films were measured under a wide range of relative humidities

  4. Substructure formation during pattern transposition from substrate into polymer blend film

    NARCIS (Netherlands)

    Cyganik, P; Budkowski, A; Steiner, U; Rysz, J; Bernasik, A; Walheim, S; Postawa, Z; Raczkowska, J

    2003-01-01

    A chemical pattern on a substrate is transposed into thin films of a ternary polymer blend during spin-casting from a common solvent. One of the blend components intercalates at interfaces between the other two phases to reduce their interfacial energy. As a result, an extensive substructure is form

  5. Development and Testing of Abrasion Resistant Hard Coats For Polymer Film Reflectors: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Jorgensen, G.; Gee, R.; DiGrazia, M.

    2010-10-01

    Reflective polymer film technology can significantly reduce the cost of solar reflectors and installed Concentrated Solar Power (CSP) plants by both reduced material cost and lower weight. One challenge of polymer reflectors in the CSP environment pertains to contact cleaning methods typically used with glass mirrors. Such contact cleaning methods can scratch the surface of polymer reflectors and thereby reduce specular reflectance. ReflecTech, Inc. (a subsidiary of SkyFuel, Inc.) and the National Renewable Energy Laboratory (NREL) initiated a cooperative research and development agreement (CRADA) to devise and develop an abrasion resistant coating (ARC) suitable for deposition onto polymer based mirror film. A number of candidate ARC products were identified as candidate formulations. Industrial collaborators prepared samples having their ARCs deposited onto ReflecTech Mirror Film pre-laminated to aluminum sheet substrates. Samples were provided for evaluation and subjected to baseline (unweathered) and accelerated exposure conditions and subsequently characterized for abrasion resistance and adhesion. An advanced ARC product has been identified that exhibits outstanding initial abrasion resistance and adhesion to ReflecTech Mirror Film. These properties were also retained after exposure to the various accelerated stress conditions. This material has been successfully manufactured as a 1.5 m wide roll-to-roll construction in a production environment.

  6. Sub-nanometer expansions of redox responsive polymer films monitored by imaging ellipsometry

    NARCIS (Netherlands)

    Cumurcu, Aysegul; Feng, X.; Dos Ramos, L.; Hempenius, M.A.; Schon, P.M.; Vancso, G.J.

    2014-01-01

    We describe a novel approach to quantitatively visualize sub nm height changes occurring in thin films of redox active polymers upon reversible electrochemical oxidation/reduction in situ and in real-time with electrochemical imaging ellipsometry (EC-IE). Our approach is based on the utilization of

  7. Gas Permeation Related to the Moisture Sorption in Films of Glassy Hydrophilic Polymers

    NARCIS (Netherlands)

    Laksmana, F. L.; Kok, P. J. A. Hartman; Frijlink, H. W.; Vromans, H.; Maarschalk, K. Van Der Voort

    2010-01-01

    The purpose of this article is to elucidate the effect of integral sorption of moisture on gas permeation in glassy hydrophilic polymers. The oxygen and the simultaneous moisture sorption into various hydroxypropyl methylcellulose (HPMC) films were measured under a wide range of relative humidities

  8. Substructure formation during pattern transposition from substrate into polymer blend film

    NARCIS (Netherlands)

    Cyganik, P; Budkowski, A; Steiner, U; Rysz, J; Bernasik, A; Walheim, S; Postawa, Z; Raczkowska, J

    2003-01-01

    A chemical pattern on a substrate is transposed into thin films of a ternary polymer blend during spin-casting from a common solvent. One of the blend components intercalates at interfaces between the other two phases to reduce their interfacial energy. As a result, an extensive substructure is form

  9. Alternating deposition films of a polymer and dendrimers bearing diphenylanthracene

    Institute of Scientific and Technical Information of China (English)

    SUN Jing; WANG Liyan; GAO Jian; YU Xi; WANG Zhiqiang

    2005-01-01

    Two generations of carboxyl-terminated poly (aryl ether) dendrimers bearing 9,10-diphenylanthracene cores are designed and synthesized. Alternating deposition of two dendrimers and poly(4-vinylpyridine) is studied with UV-Vis spectroscopy, FT-IR spectroscopy and atomic force microscopy. Experimental results indicate that this method to introduce chromophore into multilayer film can effectively prevent desorption of dye molecule. Moreover, it is found that dendrimer can inhibit the aggregation of fluorophore in film using fluorescence spectroscopy. Increase of dendrimer's generation can enhance fluorescence intensity of each fluorophore. This provides a new approach to design luminescent thin film.

  10. Undulatory delamination of thin polymer films on gold surfaces.

    Science.gov (United States)

    Chah, Soonwoo; Noolandi, Jaan; Zare, Richard N

    2005-10-20

    Using two-dimensional surface plasmon resonance measurements, we have observed the formation of traveling waves in the delamination of thin films of polydimethylsilane (PDMS) exposed to methanol. Films were spin-coated on a gold surface and the methanol was added to the top surface. The stress-induced instability caused by the swelling of the PDMS thin film when its edge is pinned to the gold surface leads to wrinkle formation and propagation at the interface. The periodic pattern is thought to be the result of an Asaro-Tiller-Grinfeld (ATG) instability.

  11. The Influence of Polymer Films on an APGD in Helium

    Science.gov (United States)

    Della Croce, Damian; Nersisyan, Gagik; Graham, William

    2006-10-01

    Electrical and optical diagnostic techniques have been used to study the influence of various polymers in the gap of a Helium APGD. A gated ICCD was used to record short exposure time images (2μs) through the development of the discharge current pulse. The APGD was generated between two parallel, glass 4mm thick) plates which cover copper mesh electrodes. The gap was 5mm. Typically a 4.4kV (peak to peak) sinusoidal voltage was applied to the powered electrode with a frequency of 30kHz. The other electrode was grounded. The system was housed in an evacuated chamber, previously evacuated to a base pressure of 10-4 Pa, before Helium was introduced to static atmospheric pressure. A spectrometer was used to record the emission spectra from the discharge. To date studies on polypropylene (PP) and polyester (PET) have been conducted and polyamide will follow. Interesting trends are evident when they are compared to those for the He APGD with no polymer present. Electrically the traces for PET are dramatically different to those for PP and no polymer, which are comparable. Imaging shows that PP yields a filamentary discharge. PET on the other hand produces a glow --type discharge. We are currently studying if the different results are intrinsic to the polymer or the anti-cling surface treatments that the polymer suppliers may be applying. DD is supported by EPSRC and Dow Corning Plasma Solutions.

  12. The role of polymer films on the oxidation of magnetite nanoparticles

    Science.gov (United States)

    Letti, C. J.; Paterno, L. G.; Pereira-da-Silva, M. A.; Morais, P. C.; Soler, M. A. G.

    2017-02-01

    A detailed investigation about the role of polymer films on the oxidation process of magnetite nanoparticles (∼7 nm diameter), under laser irradiation is performed employing micro Raman spectroscopy. To support this investigation, Fe3O4-np are synthesized by the co-precipitation method and assembled layer-by-layer with sodium sulfonated polystyrene (PSS). Polymer films (Fe3O4-np/PSS)n with n=2,3,5,7,10 and 25 bilayers are employed as a model system to study the oxidation process under laser irradiation. Raman data are further processed by principal component analysis. Our findings suggest that PSS protects Fe3O4-np from oxidation when compared to powder samples, even for the sample with the greater number of bilayers. Further, the oxidation of magnetite to maghemite occurs preferably for thinner films up to 7 bilayers, while the onset for the formation of the hematite phase depends on the laser intensity for thicker films. Water takes part on the oxidation processes of magnetite, the oxidation/phase transformation of Fe3O4-np is intensified in films with more bilayers, since more water is included in those films. Encapsulation of Fe3O4-np by PSS in layer-by-layer films showed to be very efficient to avoid the oxidation process in nanosized magnetite.

  13. Hydrodynamic surface fluctuations of polymer films by coherent X-ray scattering

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyunjung [Department of Physics and Interdisciplinary Program of Integrated Biotechnology, Sogang University, 1 Shinsu-Dong, Mapo-Gu Seoul 121-742 (Korea, Republic of)]. E-mail: hkim@sogang.ac.kr; Jiang, Zhang [Department of Physics, University of California San Diego, La Jolla, CA 92093 United States (United States); Lee, Heeju [Department of Physics and Interdisciplinary Program of Integrated Biotechnology, Sogang University, 1 Shinsu-Dong, Mapo-Gu Seoul 121-742 (Korea, Republic of); Lee, Young Joo [Department of Physics and Interdisciplinary Program of Integrated Biotechnology, Sogang University, 1 Shinsu-Dong, Mapo-Gu Seoul 121-742 (Korea, Republic of); Jiao, Xuesong; Li, Chunhua [Department of Materials Science and Engineering, SUNY at Stony Brook, Stony Brook, NY 11794 United States (United States); Lurio, Laurence [Department of Physics, Northern Illinois University, De Kalb, IL 60115 United States (United States); Rafailovich, Miriam [Department of Materials Science and Engineering, SUNY at Stony Brook, Stony Brook, NY 11794 United States (United States); Sinha, S.K. [Department of Physics and Interdisciplinary Program of Integrated Biotechnology, Sogang University, 1 Shinsu-Dong, Mapo-Gu Seoul 121-742 (Korea, Republic of); LANSCE, Los Alamos National Laboratory, Los Alamos, NM 87545 United States (United States)

    2007-05-23

    We have applied X-ray photon correlation spectroscopy (XPCS) to measure the surface dynamics of polymer films of thicknesses down to a few times of the polymer radius of gyration. XPCS is currently the only technique to measure selectively dynamics of surface and/or interfacial fluctuations of the films thanks to high brilliance and coherence of the third generation synchrotron source. The results show the behavior of the capillary waves expected in viscous liquid when the film thickness is thicker than four times of the radius of gyration. However, thinner films show a deviation indicating the need to account for viscoelasticity. We present also the theory for surface dynamics of the thermally excited fluctuations on homogenous single-layer film with arbitrary depth is generalized to describe surface and interfacial dynamics of polymeric liquid bilayer films in terms of susceptibilities, power spectra and characteristic relaxation time constants. The effects on surface dynamics originating from viscosity inhomogeneities close to surface region are investigated by the bilayer theory and compared with the surface dynamics from homogeneous single-layer films under non-slip and slip boundary conditions.

  14. Combinatorial Synthesis of and high-throughput protein release from polymer film and nanoparticle libraries.

    Science.gov (United States)

    Petersen, Latrisha K; Chavez-Santoscoy, Ana V; Narasimhan, Balaji

    2012-09-06

    Polyanhydrides are a class of biomaterials with excellent biocompatibility and drug delivery capabilities. While they have been studied extensively with conventional one-sample-at-a-time synthesis techniques, a more recent high-throughput approach has been developed enabling the synthesis and testing of large libraries of polyanhydrides(1). This will facilitate more efficient optimization and design process of these biomaterials for drug and vaccine delivery applications. The method in this work describes the combinatorial synthesis of biodegradable polyanhydride film and nanoparticle libraries and the high-throughput detection of protein release from these libraries. In this robotically operated method (Figure 1), linear actuators and syringe pumps are controlled by LabVIEW, which enables a hands-free automated protocol, eliminating user error. Furthermore, this method enables the rapid fabrication of micro-scale polymer libraries, reducing the batch size while resulting in the creation of multivariant polymer systems. This combinatorial approach to polymer synthesis facilitates the synthesis of up to 15 different polymers in an equivalent amount of time it would take to synthesize one polymer conventionally. In addition, the combinatorial polymer library can be fabricated into blank or protein-loaded geometries including films or nanoparticles upon dissolution of the polymer library in a solvent and precipitation into a non-solvent (for nanoparticles) or by vacuum drying (for films). Upon loading a fluorochrome-conjugated protein into the polymer libraries, protein release kinetics can be assessed at high-throughput using a fluorescence-based detection method (Figures 2 and 3) as described previously(1). This combinatorial platform has been validated with conventional methods(2) and the polyanhydride film and nanoparticle libraries have been characterized with (1)H NMR and FTIR. The libraries have been screened for protein release kinetics, stability and

  15. Making Glasses Conduct: Electrochemical Doping of Redox-Active Polymer Thin Films

    Science.gov (United States)

    Boudouris, Bryan

    Optoelectronically-active macromolecules have been established as promising materials in myriad organic electronic applications (e.g., organic field-effect transistors (OFETs) and organic photovoltaic (OPV) devices). To date, however, the majority of the work surrounding these materials has focused on materials with a great deal of conjugation along their macromolecular backbones and with varying degrees of crystalline structure. Here, we describe an emerging class of macromolecular charge conductors, radical polymers, that: (1) do not contain conjugation and (2) are completely amorphous glasses. Radical polymers contain non-conjugated macromolecular backbones and stable radical sites along the side chains of the electronically-active materials. In contrast to conjugated polymer systems, these materials conduct charge in the solid state through oxidation-reduction (redox) reactions along these pendant groups. Specifically, we demonstrate that controlling the chemical functionality of the pendant groups and the molecular mobility of the macromolecular backbones significantly impacts the charge transport ability of the pristine (i.e., not doped) radical polymers species. Through proper control of these crucial parameters, we show that radical polymers can have electrical conductivity and charge mobility values on par with commonly-used conjugated polymers. Importantly, we also highlight the ability to dope radical polymers with redox-active small molecule species. This doping, in turn, increases the electrical conductivity of the glassy radical polymer thin films in a manner akin to what is observed in traditional conjugated polymer systems. In this way, we establish a means by which to fabricate optically-transparent and colorless thin film glasses capable of conducting charge in a rather rapid manner. We anticipate that these fundamental insights will prove crucial in developing new transparent conducting layers for future electronic applications.

  16. Synthetic Reference Materials Based on Polymer Films for the Control of Welding Fumes Composition

    Science.gov (United States)

    Kuznetsova, O. V.; Kuznetsova, A. N.; Begunova, L. A.

    2017-04-01

    Analysis of the current hygienic situation in the welding production showed that the intensification of welding processes involves the deterioration of air quality, which negatively affects the welders health. Welders are exposed to a variety of metal fumes, including manganese that may elevate the risk for neurological diseases. The control of metals concentration in the air of the working area is difficult due to the lack of reference materials. The creation of reference materials of welding fumes composition is a challenge due to chemical characteristics of their physical properties. Synthetic samples in a form of the polymer film containing powder particles of welding fumes were create. Studies on the selection of the polymer were done. Experiments proved that the qualitative materials of synthetic welding fumes are obtained by using polyvinyl alcohol. The metals concentration in the samples was determined by X-ray fluorescence analysis. The obtained data demonstrates indirectly the uniform distribution of welding fumes powder particles on the polymer film.

  17. Phase Separation of Silicon-Containing Polymer/Polystyrene Blends in Spin-Coated Films.

    Science.gov (United States)

    Li, Yang; Hu, Kai; Han, Xiao; Yang, Qinyu; Xiong, Yifeng; Bai, Yuhang; Guo, Xu; Cui, Yushuang; Yuan, Changsheng; Ge, Haixiong; Chen, Yanfeng

    2016-04-19

    In this Article, two readily available polymers that contain silicon and have different surface tensions, polydimethylsiloxane (PDMS) and polyphenylsilsequioxane (PPSQ), were used to produce polymer blends with polystyrene (PS). Spin-coated thin films of the polymer blends were treated by O2 reactive-ion etching (RIE). The PS constituent was selectively removed by O2 RIE, whereas the silicon-containing phase remained because of the high etching resistance of silicon. This selective removal of PS substantially enhanced the contrast of the phase separation morphologies for better scanning electron microscope (SEM) and atomic force microscope (AFM) measurements. We investigated the effects of the silicon-containing constituents, polymer blend composition, concentration of the polymer blend solution, surface tension of the substrate, and the spin-coating speed on the ultimate morphologies of phase separation. The average domain size, ranging from 100 nm to 10 μm, was tuned through an interplay of these factors. In addition, the polymer blend film was formed on a pure organic layer, through which the aspect ratio of the phase separation morphologies was further amplified by a selective etching process. The formed nanostructures are compatible with existing nanofabrication techniques for pattern transfer onto substrates.

  18. Roll-to-roll embossing of optical linear Fresnel lens polymer film for solar concentration.

    Science.gov (United States)

    Zhang, XinQuan; Liu, Kui; Shan, Xuechuan; Liu, Yuchan

    2014-12-15

    Roll-to-roll manufacturing has been proven to be a high-throughput and low-cost technology for continuous fabrication of functional optical polymer films. In this paper, we have firstly studied a complete manufacturing cycle of linear Fresnel lens polymer film for solar concentration in the aspects of ultra-precision diamond machining of metal roller mold, roll-to-roll embossing, and measurement on film profile and functionality. A metal roller mold patterned with linear Fresnel lenses is obtained using single point diamond turning technique. The roller mold is installed onto a self-developed roll-to-roll UV embossing system to realize continuous manufacturing of linear Fresnel lens film. Profile measurement of the machined roller mold and the embossed polymer film, which is conducted using a stylus profilometer, shows good agreement between measured facet angles with designed ones. Functionality test is conducted on a solar simulation system with a reference solar cell, and results show that strong light concentration is realized.

  19. Resonant Infrared Matrix Assisted Pulsed Laser Deposition of Polymers: Improving the Morphology of As-Deposited Films

    Science.gov (United States)

    Bubb, Daniel; Papantonakis, Michael; Collins, Brian; Brookes, Elijah; Wood, Joshua; Gurudas, Ullas

    2008-03-01

    Resonant infrared matrix assisted pulsed laser deposition has been used to deposit thin films of PMMA, a widely used industrial polymer. This technique is similar to conventional pulsed laser deposition, except that the polymer to be deposited is dissolved in a solvent and the solution is frozen before ablation in a vacuum chamber. The laser wavelength is absorbed by a vibrational band in the frozen matrix. The polymer lands on the substrate to form a film, while the solvent is pumped away. Our preliminary results show that the surface roughness of the as-deposited films depends strongly on the differential solubility radius, as defined by Hansen solubility parameters of the solvent and the solubility radius of the polymer. Our results will be compared with computational and experimental studies of the same polymer using a KrF (248 nm) laser. The ejection mechanism will be discussed as well as the implications of these results for the deposition of smooth high quality films.

  20. Styromal based polymer films modified with copper microparticles

    Directory of Open Access Journals (Sweden)

    Viktor F. Vargalyuk

    2016-12-01

    Full Text Available A method for the synthesis of polymeric film based on a copolymer of styrene and maleic anhydride (stiromal and oligodiol was suggested. Block copolymer of ethylene glycol and propylene glycol was used as oligodiol. It was shown that synthesized materials have moderate water swelling capacity in and ion-exchange properties. Static exchange capacity in 0.1 mol/L NaOH aqueous solution is within the interval of 1.44–1.76 mmol/g. At air-dry state films have a tensile strength of 4–6.6 MPa and an elongation at break tensile 38–61 %. The effect of stiromal molecular weight and oligodiol type, and conditions of film formation on ion-exchange and physical-mechanical properties of the films was studied. The synthesized material appeared to be able to sorb Cu2+-ions from neutral and acidic solutions. The distribution coefficient in case of sorption from slightly acidic solution with Cu2+ concentration of 50 mg/L was 48–50. Composite material with a metal submicroparticles uniformly distributed in the polymeric matrix was obtained by chemical reduction of copper ions sorbed. It was found that the film acquires electric conductivity, as a result of filling of metal particles, which allows copper electrodeposition on the film surface.

  1. Electrochemical co-deposition of conductive polymer-silica hybrid thin films.

    Science.gov (United States)

    Raveh, Moran; Liu, Liang; Mandler, Daniel

    2013-07-14

    Conductive polymers, such as polypyrrole (ppy), have been the subject of numerous studies due to their promising applications in organic solar cells, flexible electronics, electrochromic devices, super capacitors, etc. Yet, their application is still limited as a result of poor processability. Silica has been reported to improve the mechanical strength and adhesion of conductive polymer films. In this work, we propose a controllable electrochemical approach for preparing ppy-silica hybrid thin films from a solution containing both pyrrole and silane monomers. It is known that pyrrole can be electropolymerised using anodic potentials, while silica can be electrodeposited under cathodic potentials. Thus, we studied the formation of ppy-silica hybrid thin films on a stainless steel surface by applying alternating potentials, i.e. cathodic followed by anodic pulses (denoted C + A) or anodic followed by cathodic pulses (denoted A + C). We show that by controlling the deposition potential and time for the cathodic and anodic pulses, the film thickness and composition can be manipulated well as analysed using profilometry and EDX. The element depth profile of the films was characterized using secondary ion mass spectroscopy (SIMS). In essence, for the C + A process, pyrrole diffuses through the cathodically electrodeposited wet silica gel layer and undergoes anodic polymerisation on the substrate, while for the A + C process, silane can be electrodeposited both on top of the anodically electrodeposited conductive ppy films as well as on the stainless steel through the pinholes in the ppy film. This offers a simple approach for tuning the structure of conductive polymer-sol-gel composite films.

  2. Highly efficient Cu(In,Ga)Se2 solar cells grown on flexible polymer films.

    Science.gov (United States)

    Chirilă, Adrian; Buecheler, Stephan; Pianezzi, Fabian; Bloesch, Patrick; Gretener, Christina; Uhl, Alexander R; Fella, Carolin; Kranz, Lukas; Perrenoud, Julian; Seyrling, Sieghard; Verma, Rajneesh; Nishiwaki, Shiro; Romanyuk, Yaroslav E; Bilger, Gerhard; Tiwari, Ayodhya N

    2011-09-18

    Solar cells based on polycrystalline Cu(In,Ga)Se(2) absorber layers have yielded the highest conversion efficiency among all thin-film technologies, and the use of flexible polymer films as substrates offers several advantages in lowering manufacturing costs. However, given that conversion efficiency is crucial for cost-competitiveness, it is necessary to develop devices on flexible substrates that perform as well as those obtained on rigid substrates. Such comparable performance has not previously been achieved, primarily because polymer films require much lower substrate temperatures during absorber deposition, generally resulting in much lower efficiencies. Here we identify a strong composition gradient in the absorber layer as the main reason for inferior performance and show that, by adjusting it appropriately, very high efficiencies can be obtained. This implies that future manufacturing of highly efficient flexible solar cells could lower the cost of solar electricity and thus become a significant branch of the photovoltaic industry.

  3. Near-field lithography on the azobenzene polymer liquid crystal films

    Institute of Scientific and Technical Information of China (English)

    Douguo Zhang; Jian Liu; Zebo Zhang; Li Cao; Anlian Pan; Pei Wang; Yonghua Lu; Ming Bai; Jun Yang; Lin Tang; Jiangying Zhang; Hai Ming; Qijin Zhang

    2005-01-01

    @@ In this article, we reported near-field research on azobenzene polymer liquid crystal films using scanning near-field optical microscopy (SNOM). Optical writing and subsequently topographic reading of the patterns with subwavelength resolution were carried out in our experiments. Nanometer scale dots and lines were successfully fabricated on the films and the smallest dot diameter is about 120 nm. The width of the line fabricated is about 250 nm. This method is also a choice for nanolithography. The mechanism of the surface deformation on the polymer films was briefly analyzed from the viewpoint of gradient force in the optical near field. The intensity distribution of the electric field near the tip aperture was numerically simulated using finite-difference time-domain (FDTD) method and the numerical simulation results were consistent with the experimental results.

  4. Physical and thermal properties of 8 MeV electron beam irradiated HPMC polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Sangappa [Department of Studies in Physics, Mangalore University, Mangalagangotri 574 199 (India)], E-mail: sangappa@mangaloreuniversity.ac.in; Demappa, T.; Mahadevaiah [Department of Polymer Science, Sir M V, P G Center, University of Mysore, Mandya 575 007 (India); Ganesha, S. [Microtron Center, Mangalore University, Mangalagangotri 574 199 (India); Divakara, S. [Department of Physics, East Point College of Engineering and Technology, Bangalore 560049 (India); Pattabi, Manjunath [Department of Material Science, Mangalore University, Mangalagangotri 574 199 (India); Somashekar, R. [Department of Studies in Physics, University of Mysore, Manasagangotri, Mysore 570 006 (India)

    2008-09-15

    Microstructural modification in hydroxypropyl methylcellulose (HPMC) polymer films induced by electron irradiation is studied. Irradiation was performed in air at room temperature using a 8 MeV electron accelerator at doses of 25, 50, 75 and 100 kGy. Irradiation can be used to crosslink or degrade the desired component or to fix the polymer morphology. Changes in microstructural parameters, crystallinity and thermal properties in virgin and irradiated HPMC films have been studied using wide angle X-ray scattering data and differential scanning calorimetry. The heat of fusion and the degree of crystallinity are found to be highest for unirradiated HPMC and the crystallite size is larger in virgin HPMC films.

  5. Synthesis and characterization of nanocomposite polymer blend electrolyte thin films by spin-coating method

    Science.gov (United States)

    Chapi, Sharanappa; Niranjana, M.; Devendrappa, H.

    2016-05-01

    Solid Polymer blend electrolytes based on Polyethylene oxide (PEO) and poly vinyl pyrrolidone (PVP) complexed with zinc oxide nanoparticles (ZnO NPs; Synthesized by Co-precipitation method) thin films have prepared at a different weight percent using the spin-coating method. The complexation of the NPs with the polymer blend was confirmed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR). The variation in film morphology was examined by polarized optical micrographs (POMs). The thermal behavior of blends was investigated under non-isothermal conditions by differential thermal analyses (DTA). A single glass transition temperature for each blend was observed, which supports the existence of compatibility of such system. The obtained results represent that the ternary based thin films are prominent materials for battery and optoelectronic device applications.

  6. Refractometric discrimination of void-space filling and swelling during vapour sorption in polymer films.

    Science.gov (United States)

    Cross, G H; Ren, Y; Swann, M J

    2000-12-01

    Thin polymeric films have been deposited as upper cladding layers on a new integrated optical interferometer fabricated from layers of silicon oxynitride on a silicon wafer. The evanescent field of the probing waveguide mode transduces refractive index changes in the polymer layer into the measured phase changes in the device. Real-time measurement of index change and its sign is obtained. Upon exposure to humid air, we record water sorption by films of poly(vinyl pyrrolidone) by a rapid positive index change for void-space filling followed by a slow negative index change for swelling. Sorption of water vapor into a thin film of the viscous liquid polymer polyethylenimine shows only swelling mode behaviour and a simple constitutive model can be applied to give the fractional water occupied volume.

  7. Imaging the Effect of Electrical Breakdown in Multilayer Polymer Capacitor Films

    Science.gov (United States)

    Wolak, Mason

    2013-03-01

    Multilayer polymer films show great promise as the dielectric material in high energy density capacitors. Such films show enhancement in both dielectric strength (EB) and energy density (Ud) relative to monolithic films of either source polymer. Composites are typically comprised of alternating layers of a high EB polymer and a high permittivity polymer. Here, we discuss a multilayer system based on polycarbonate (PC) interleaved with polyvinylidene fluoride-hexafluoropropylene (PVDF-HFP). The dielectric properties of the PC/PVDF-HFP films are influenced by both composition and individual layer thickness. Optimized films show EB = 750 kV/mm and Ud = 13 J/cm3. Further enhancements in EB and Ud are expected through optimization of the component polymers, composition, and layer structure. To guide next generation design, it is important to understand the breakdown mechanism, as it directly influences EB. To elucidate the role of the layer structure during electrical breakdown, we use a tandem focused ion beam (FIB) / scanning electron microscope (SEM) imaging technique. The technique allows us to image the internal layer structure of both `as fabricated' control films, and those subjected to high electric fields. It is therefore a powerful tool to assess film quality and analyze failure mechanisms. Specifically, the FIB is used to mill site-specific holes in a film and the resulting cross-sections are imaged via SEM. Individual layers are easily resolved down to 50 nm. For films subjected to electrical breakdown, the location and propagation of damage is tracked with sequential FIB milling and SEM imaging. Spatially resolved FIB/SEM imaging allows preparation of quasi-3D maps displaying the evolution of internal voids in areas adjacent to the breakdown location (pinhole of d = 30-80 microns). A majority of the voids are localized at the interfaces between layers and may propagate as far as 30-50 microns from the pinhole. The data suggest that the enhancement in

  8. Measuring Exciton Migration in Conjugated Polymer Films with Ultrafast Time Resolved Stimulated Emission Depletion Microscopy

    Science.gov (United States)

    Penwell, Samuel

    Conjugated polymers are highly tunable organic semiconductors, which can be solution processed to form thin films, making them prime candidates for organic photovoltaic devices. One of the most important parameters in a conjugated polymer solar cell is the exciton diffusion length, which depends on intermolecular couplings, and is typically on the order of 10 nm. This mean exciton migration can vary dramatically between films and within a single film due to heterogeneities in morphology on length scales of 10's to 100's nm. To study the variability of exciton diffusion and morphology within individual conjugated polymer films, we are adapting stimulated emission depletion (STED) microscopy. STED is typically used in biology with sparse well-engineered fluorescent labels or on NV-centers in diamond. I will, however, describe how we have demonstrated the extension of STED to conjugated polymer films and nanoparticles of MEH-PPV and CN-PPV, despite the presence of two photon absorption, by taking care to first understand the material's photophysical properties. We then further adapt this approach, by introducing a second ultrafast STED pulse at a variable delay. Excitons that migrate away from the initial subdiffraction excitation volume during the ps-ns time delay, are preferentially quenched by the second STED pulse, while those that remain in the initial volume survive. The resulting effect of the second STED pulse is modulated by the degree of migration over the ultrafast time delay, thus providing a new method to study exciton migration. Since this technique utilizes subdiffraction optical excitation and detection volumes with ultrafast time resolution, it provides a means of spatially and temporally resolving measurements of exciton migration on the native length and time scales. In this way, we will obtain a spatiotemporal map of exciton distributions and migration that will help to correlate the energetic landscape to film morphology at the nanoscale.

  9. Polymer Films with Ion-Synthesized Cobalt and Iron Nanoparticles

    DEFF Research Database (Denmark)

    Popok, Vladimir

    2014-01-01

    The current paper presents an overview and analysis of data obtained on a few sets of polymer samples implanted by iron and cobalt. The low-energy (40 keV) implantations were carried out into polyimide and polyethyleneterephthalate with fluences between 2.5x10e16-1.5x10e17 cm-2. The samples were...

  10. Physics and technology of optical storage in polymer thin films

    DEFF Research Database (Denmark)

    Ramanujam, P.S.; Hvilsted, Søren; Ujhelyi, F.

    2001-01-01

    system based on polarization holography is described. A storage density of greater than 10MB/cm2 has been achieved so far, with a potential increase to 100MB/cm(2) using multiplexing techniques and software correction. Finally the role of surface relief in azobenzene polymers on irradiation...

  11. Self-Supported Crack-Free Conducting Polymer Films with Stabilized Wrinkling Patterns and Their Applications

    Science.gov (United States)

    Xie, Jixun; Han, Xue; Ji, Haipeng; Wang, Juanjuan; Zhao, Jingxin; Lu, Conghua

    2016-11-01

    Self-supported conducting polymer films with controlled microarchitectures are highly attractive from fundamental and applied points of view. Here a versatile strategy is demonstrated to fabricate thin free-standing crack-free polyaniline (PANI)-based films with stable wrinkling patterns. It is based on oxidization polymerization of pyrrole inside a pre-wrinkled PANI film, in which the wrinkled PANI film is used both as a template and oxidizing agent for the first time. The subsequently grown polypyrrole (PPy) and the formation of interpenetrated PANI/PPy networks play a decisive role in enhancing the film integrity and the stability of wrinkles. This enhancing effect is attributed to the modification of internal stresses by the interpenetrated PANI/PPy microstructures. Consequently, a crack-free film with stable controlled wrinkles such as the wavelength, orientation and spatial location has been achieved. Moreover, the wrinkling PANI/PPy film can be removed from the initially deposited substrate to become free-standing. It can be further transferred onto target substrates to fabricate hierarchical patterns and functional devices such as flexible electrodes, gas sensors, and surface-enhanced Raman scattering substrates. This simple universal enhancing strategy has been extended to fabrication of other PANI-based composite systems with crack-free film integrity and stabilized surface patterns, irrespective of pattern types and film geometries.

  12. Influence of processing and intrinsic polymer parameters on photochemical stability of polythiophene thin films

    DEFF Research Database (Denmark)

    Vesterager Madsen, Morten; Tromholt, Thomas; Böttiger, Arvid P.L.

    2012-01-01

    Intrinsic polymer parameters such as regio-regularity, molecular weight, and crystallinity play an important role when studying polymer stability. 18 different batches of poly-3-hexyl-thiophene (P3HT) were degraded in a solar simulator (AM1.5G, 1000 W/m2) and the degradation kinetics were monitored......-to-tail connected thiophene units. Annealing was found to relax the P3HT films and increase conjugation length and, in turn, increase stability observed as a delayed spectral blueshift caused by photochemical degradation. Crystallinity was found to play a minor role in terms of stability. Oxygen diffusion and light...... shielding effects were shown to have a negligible effect on the photochemical degradation rate. The results obtained in this work advance the understanding of polymer stability and will help improve the design of materials used for polymer solar cells resulting in longer lifetimes, which will push...

  13. Polymer assisted solution processing of Ti-doped indium oxide transparent conducting thin films for organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Vishwanath, Sujaya Kumar [Division of Advanced Materials Engineering, Kongju National University, Cheonan, Chungchungnam-do 331-717 (Korea, Republic of); Jin, Won-Yong [The Graduate School of Flexible and Printable Electronics, Polymer BIN Fusion Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Kang, Jae-Wook, E-mail: jwkang@jbnu.ac.kr [The Graduate School of Flexible and Printable Electronics, Polymer BIN Fusion Research Center, Chonbuk National University, Jeonju 561-756 (Korea, Republic of); Kim, Jihoon, E-mail: jihoon.kim@kongju.ac.kr [Division of Advanced Materials Engineering, Kongju National University, Cheonan, Chungchungnam-do 331-717 (Korea, Republic of)

    2015-05-15

    Highlights: • Polymer assisted solution process. • Ti-doped indium oxide (TIO) transparent conducting films. • Replacement of sputtered ITO with polymer-assisted-solution-coated TIO films. • High mobility transparent conducting films. • Application of polymer-assisted-solution-coated TIO films to organic solar cells. - Abstract: We report the preparation and evaluation of Ti-doped indium oxide (TIO) transparent conducting films by a polymer-assisted solution (PAS) process, as well as the evaluation of this type of film as a transparent cathode in an inverted organic solar cell (IOCS). Both Ti- and In-PASs have been synthesized by coordinating Ti- and In-anionic complexes with polyethyleneimine. The final TIO–PAS was formed by mixing Ti-PAS into In-PAS with a Ti concentration between 1 at.% and 7 at.%. The TIO–PAS was spin-coated onto glass substrates to form uniform thin films of Ti-doped indium oxide, which were then annealed at high temperature. The optimum Ti concentration to achieve the best electrical and optical properties of PAS–TIO films was found to be 3 at.%. With the film thickness of 650 nm, PAS–TIO films had a sheet resistance of 65 Ω/sq and an optical transmittance greater than 85%. The feasibility of PAS-coated TIO thin film as a transparent electrode was evaluated by applying it to the fabrication of IOSCs, which showed the energy conversion efficiency of 4.60%.

  14. Liposomes as drug deposits in multilayered polymer films.

    Science.gov (United States)

    Lynge, Martin E; Laursen, Marie Baekgaard; Hosta-Rigau, Leticia; Jensen, Bettina E B; Ogaki, Ryosuke; Smith, Anton A A; Zelikin, Alexander N; Städler, Brigitte

    2013-04-24

    The ex vivo growth of implantable hepatic or cardiac tissue remains a challenge and novel approaches are highly sought after. We report an approach to use liposomes embedded within multilayered films as drug deposits to deliver active cargo to adherent cells. We verify and characterize the assembly of poly(l-lysine) (PLL)/alginate, PLL/poly(l-glutamic acid), PLL/poly(methacrylic acid) (PMA), and PLL/cholesterol-modified PMA (PMAc) films, and assess the myoblast and hepatocyte adhesion to these coatings using different numbers of polyelectrolyte layers. The assembly of liposome-containing multilayered coatings is monitored by QCM-D, and the films are visualized using microscopy. The myoblast and hepatocyte adhesion to these films using PLL/PMAc or poly(styrenesulfonate) (PSS)/poly(allyl amine hydrochloride) (PAH) as capping layers is evaluated. Finally, the uptake of fluorescent lipids from the surface by these cells is demonstrated and compared. The activity of this liposome-containing coating is confirmed for both cell lines by trapping the small cytotoxic compound thiocoraline within the liposomes. It is shown that the biological response depends on the number of capping layers, and is different for the two cell lines when the compound is delivered from the surface, while it is similar when administered from solution. Taken together, we demonstrate the potential of liposomes as drug deposits in multilayered films for surface-mediated drug delivery.

  15. Fluorescent molecularly imprinted polymer film binds glucose with a concomitant changes in fluorescence.

    Science.gov (United States)

    Manju, S; Hari, P R; Sreenivasan, K

    2010-10-15

    A fluorescent molecularly imprinted polymeric formulation capable of picking up glucose from aqueous media is reported. The fluorescence intensity of the polymer film was found to reduce proportionally with the concentration of glucose facilitating its use as a glucose sensing element. We used commercially available tear fluid to demonstrate the ability of the film to recognize glucose among other sugar molecules. Fluorescence was measured after equilibrating the film in tear fluid in the presence of a mixture of different sugars. We observed a reduction in fluorescence intensity due to the nonspecific binding of the sugars. The intensity remains the same even if we added additional quantities of the sugars. Interestingly, the fluorescence intensity of the film was found to decrease proportionally when varied concentrations of glucose was added indicating the ability of the film to recognize and bind glucose from a mixture of other sugars. Detectable changes in fluorescence intensity were observed with a concentration of 10 μg/mL of glucose. The results show that the polymer film could be used for detecting glucose in aqueous fluids such as tear. Copyright © 2010 Elsevier B.V. All rights reserved.

  16. Temperature- and thickness-dependent elastic moduli of polymer thin films

    Directory of Open Access Journals (Sweden)

    Ao Zhimin

    2011-01-01

    Full Text Available Abstract The mechanical properties of polymer ultrathin films are usually different from those of their counterparts in bulk. Understanding the effect of thickness on the mechanical properties of these films is crucial for their applications. However, it is a great challenge to measure their elastic modulus experimentally with in situ heating. In this study, a thermodynamic model for temperature- (T and thickness (h-dependent elastic moduli of polymer thin films Ef(T,h is developed with verification by the reported experimental data on polystyrene (PS thin films. For the PS thin films on a passivated substrate, Ef(T,h decreases with the decreasing film thickness, when h is less than 60 nm at ambient temperature. However, the onset thickness (h*, at which thickness Ef(T,h deviates from the bulk value, can be modulated by T. h* becomes larger at higher T because of the depression of the quenching depth, which determines the thickness of the surface layer δ.

  17. Preparation and photochromic behavior of crosslinked polymer thin films containing polyoxometalates

    Energy Technology Data Exchange (ETDEWEB)

    Chen Jie; Liu Yan; Xiong Deqi [College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026 (China); Feng Wei [College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026 (China)], E-mail: weifeng@newmail.dlmu.edu.cn; Cai Weimin [College of Environmental Science and Engineering, Dalian Maritime University, Dalian 116026 (China)

    2008-03-31

    A series of reversible photochromic nanocomposite films were prepared by entrapping phosphotungstic acid (PWA) and molybdenumphsophoric acid (PMoA) into P(VP-BVA), which was a crosslinked polymer based on N-vinylpyrrolidone (VP) and bisvinyl-A (BVA). The microstructure, photochromic behavior and mechanism of the films were studied with transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), ultraviolet-visible spectra (UV-vis) and electron resonance spectra (ESR). The TEM image showed that the polyoxometalates particles had regular microstructure with narrow size distribution (average diameter of 30 nm) in hybrid films. FT-IR results showed that the Keggin geometry of polyoxometalates (POM) was still preserved inside the composites and strong coulombic interaction between POM and crosslinked polymer matrix was built. Irradiated with ultraviolet light, the transparent films changed from colorless to blue and showed reversible photochromism. Oxygen plays an important role during the bleaching process. PMoA/P(VP-BVA) film had higher photochromic efficiency and slower bleaching reaction than PWA/P(VP-BVA) film. The characteristic signals of W (V) or Mo (V) in ESR spectra indicated that electron transfer occurred between the organic substrates and heteropolyanions under UV irradiation, which induced heteropolyanions to heteropolybules with simultaneous oxidation of the organic substrates.

  18. Electron beam and gamma ray irradiated polymer electrolyte films: Dielectric properties

    Directory of Open Access Journals (Sweden)

    S. Raghu

    2016-04-01

    Full Text Available In this study, polymer electrolyte films were irradiated with electron beam (EB and Gamma ray (GR at 50 and 150 kGy. The induced chemical changes in films due to irradiations have been confirmed from the Fourier Transform Infra red (FT-IR spectra. The X-ray Diffractometry (XRD results show that crystallinity decreases by ∼20% in EB and ∼10% in GR irradiated films respectively compared to non-irradiated film. The micro structural arrangement was investigated by Scanning Electronic Microscopy (SEM and the images reveal that there is a substantial improvement in the surface morphology in irradiated films. The real (ε′ and imaginary (ε″ dielectric constant and AC conductivity are found to increase with increase in irradiation dose. Improved dielectric properties and conductivity (1.74 x 10−4 & 1.15 x 10−4 S/cm, respectively, for EB and GR irradiated films at room temperature after irradiation and it confirm that EB and GR irradiation can be simple and effective route to obtaining highly conductive polymer electrolytes. From this study it is confirm that EB is more effectiveness than GR irradiation.

  19. Humidity versus photo-stability of metal halide perovskite films in a polymer matrix.

    Science.gov (United States)

    Manshor, Nurul Ain; Wali, Qamar; Wong, Ka Kan; Muzakir, Saifful Kamaluddin; Fakharuddin, Azhar; Schmidt-Mende, Lukas; Jose, Rajan

    2016-08-21

    Despite the high efficiency of over 21% reported for emerging thin film perovskite solar cells, one of the key issues prior to their commercial deployment is to attain their long term stability under ambient and outdoor conditions. The instability in perovskite is widely conceived to be humidity induced due to the water solubility of its initial precursors, which leads to decomposition of the perovskite crystal structure; however, we note that humidity alone is not the major degradation factor and it is rather the photon dose in combination with humidity exposure that triggers the instability. In our experiment, which is designed to decouple the effect of humidity and light on perovskite degradation, we investigate the shelf-lifetime of CH3NH3PbI3 films in the dark and under illumination under high humidity conditions (Rel. H. > 70%). We note minor degradation in perovskite films stored in a humid dark environment whereas upon exposure to light, the films undergo drastic degradation, primarily owing to the reactive TiO2/perovskite interface and also the surface defects of TiO2. To enhance its air-stability, we incorporate CH3NH3PbI3 perovskite in a polymer (poly-vinylpyrrolidone, PVP) matrix which retained its optical and structural characteristics in the dark for ∼2000 h and ∼800 h in room light soaking, significantly higher than a pristine perovskite film, which degraded completely in 600 h in the dark and in less than 100 h when exposed to light. We attribute the superior stability of PVP incorporated perovskite films to the improved structural stability of CH3NH3PbI3 and also to the improved TiO2/perovskite interface upon incorporating a polymer matrix. Charge injection from the polymer embedded perovskite films has also been confirmed by fabricating solar cells using them, thereby providing a promising future research pathway for stable and efficient perovskite solar cells.

  20. Measurement of in-plane thermal conductivity in polymer films

    OpenAIRE

    Qingshuo Wei; Chinatsu Uehara; Masakazu Mukaida; Kazuhiro Kirihara; Takao Ishida

    2016-01-01

    Measuring the in-plane thermal conductivity of organic thermoelectric materials is challenging but is critically important. Here, a method to study the in-plane thermal conductivity of free-standing films (via the use of commercial equipment) based on temperature wave analysis is explored in depth. This subject method required a free-standing thin film with a thickness larger than 10 μm and an area larger than 1 cm2, which are not difficult to obtain for most solution-processable organic ther...

  1. Polymer Stress-Gradient Induced Migration in Thin Film Flow Over Topography

    Science.gov (United States)

    Tsouka, Sophia; Dimakopoulos, Yiannis; Tsamopoulos, John

    2014-11-01

    We consider the 2D, steady film flow of a dilute polymer solution over a periodic topography. We examine how the distribution of polymer in the planarization of topographical features is affected by flow intensity and physical properties. The thermodynamically acceptable, Mavrantzas-Beris two-fluid Hamiltonian model is used for polymer migration. The resulting system of differential equations is solved via the mixed FE method combined with an elliptic grid generation scheme. We present numerical results for polymer concentration, stress, velocity and flux of components as a function of the non-dimensional parameters of the problem (Deborah, Peclet, Reynolds and Capillary numbers, ratio of solvent viscosity to total liquid viscosity and geometric features of the topography). Polymer migration to the free surface is enhanced when the cavity gets steeper and deeper. This increases the spatial extent of the polymer depletion layer and induces strong banding in the stresses away from the substrate wall, especially in low polymer concentration. Macromolecules with longer relaxation times are predicted to migrate towards the free surface more easily, while high surface tension combined with a certain range of Reynolds numbers affects the free surface deformations. Work supported by the General Secretariat of Research & Technology of Greece through the program ``Excellence'' (Grant No. 1918) in the framework ``Education and Lifelong Learning'' co-funded by the ESF.

  2. Electrically Conducting Polymer-Copper Sulphide Composite Films, Preparation by Treatment of Polymer-Copper (2) Acetate Composites with Hydrogen Sulfide

    Science.gov (United States)

    Yamamoto, Takakazu; Kamigaki, Takahira; Kubota, Etsuo

    1988-01-01

    Polymer copper sulfide composite films were prepared by treatment of polymer poly(vinyl chloride), poly(acrylonitrile), copolymer of vinyl chloride and vinyl acetate (90:10), and ABS resin copper (2) acetate composites with hydrogen sulfide. The films showed electrical conductivity higher than 0.015 S/cm when they contained more than 20 wt percent of copper sulfide. A poly(acrylonitrile)-copper sulfide composite film containing 40 to 50 wt percent of copper sulfide showed electrical conductivity of 10 to 150.0 S/cm and had relatively high mechanical strength to be used in practical purposes.

  3. Chemical and microstructural characterizations of plasma polymer films by time-of-flight secondary ion mass spectrometry and principal component analysis

    Energy Technology Data Exchange (ETDEWEB)

    Cossement, Damien, E-mail: damien.cossement@materianova.be [Materia Nova Research Center, Parc Initialis, 1, Avenue Nicolas Copernic, B-7000 Mons (Belgium); Renaux, Fabian [Materia Nova Research Center, Parc Initialis, 1, Avenue Nicolas Copernic, B-7000 Mons (Belgium); Thiry, Damien; Ligot, Sylvie [Chimie des Interactions Plasma-Surface (ChIPS), CIRMAP, Université de Mons, 23 Place du Parc, B-7000 Mons (Belgium); Francq, Rémy; Snyders, Rony [Materia Nova Research Center, Parc Initialis, 1, Avenue Nicolas Copernic, B-7000 Mons (Belgium); Chimie des Interactions Plasma-Surface (ChIPS), CIRMAP, Université de Mons, 23 Place du Parc, B-7000 Mons (Belgium)

    2015-11-15

    Graphical abstract: - Highlights: • Plasma polymer films have a chemical selectivity and a cross-linking degree which are known to vary in opposite trends. • Three plasma polymers families were used as model organic layers for cross-linking evaluation by ToF-SIMS and principal component analysis. • The data were cross-checked with related functional properties that are known to depend on the cross-linking degree (stability in solvent, mechanical properties, …). • The suggested cross-linking evaluation method was validated for different families of plasma polymers demonstrating that it can be seen as a “general” method. - Abstract: It is accepted that the macroscopic properties of functional plasma polymer films (PPF) are defined by their functional density and their crosslinking degree (χ) which are quantities that most of the time behave in opposite trends. If the PPF chemistry is relatively easy to evaluate, it is much more challenging for χ. This paper reviews the recent work developed in our group on the application of principal component analysis (PCA) to time-of-flight secondary ion mass spectrometric (ToF-SIMS) positive spectra data in order to extract the relative cross-linking degree (χ) of PPF. NH{sub 2}-, COOR- and SH-containing PPF synthesized in our group by plasma enhanced chemical vapor deposition (PECVD) varying the applied radiofrequency power (P{sub RF}), have been used as model surfaces. For the three plasma polymer families, the scores of the first computed principal component (PC1) highlighted significant differences in the chemical composition supported by X-Ray photoelectron spectroscopy (XPS) data. The most important fragments contributing to PC1 (loadings > 90%) were used to compute an average C/H ratio index for samples synthesized at low and high P{sub RF}. This ratio being an evaluation of χ, these data, accordingly to the literature, indicates an increase of χ with P{sub RF} excepted for the SH-PPF. These results have

  4. Thermally stimulated discharge conductivity in polymer composite thin films

    Indian Academy of Sciences (India)

    V S Sangawar; P S Chikhalikar; R J Dhokne; A U Ubale; S D Meshram

    2006-08-01

    This paper describes the results of thermally stimulated discharge conductivity study of activated charcoal–polyvinyl chloride (PVC) thin film thermoelectrets. TSDC has been carried out in the temperature range 308–400°K and at four different polarizing fields. Results are discussed on the basis of mobility of activated charcoal and polyvinyl chloride chains.

  5. Dynamics of Polymer Blend Film Formation During Spin Coating

    Science.gov (United States)

    Mouhamad, Youmna; Clarke, Nigel; Jones, Richard A. L.; Geoghegan, Mark

    2012-02-01

    Spin casting is a process broadly used to obtain a uniform film on a flat substrate. A homogeneous film results from the balance between centrifugal and viscous forces. Here we revisit the Meyerhofer model of the spin casting process by taking in account the centrifugal forces, a uniform time dependent evaporation rate, and account for the changes in viscosity using the Huggins intrinsic viscosity. Time resolved light reflectometry is used to monitor the thickness changes of a polystyrene-poly(methyl methacrylate)(which we denote as PS and PMMA) film initially dissolved in toluene and spin cast for ten seconds at 1000 rpm. The experimental data are in good agreement with the model. We also investigate how the volume fraction of PS and PMMA influences the thinning of the film during spin casting. A distinct change in the temporal evolution of thickness as a function of time delimits the first phase of the spin casting process where centrifugal forces are dominant from a second phase dominated by the solvent evaporation. This hypothesis is supported by in-situ off specular scattering data. The time at which this change from centrifugal to evaporation-dominated behaviour is delayed as the volume fraction of PMMA increases.

  6. Polymer Thin Film Buckling: Wrinkling and Strain Localizations

    Science.gov (United States)

    Ebata, Yuri; Croll, Andrew B.; Crosby, Alfred J.

    2011-03-01

    Out of plane deformations of thin films are observed in everyday life, e.g. wrinkled aging human skin or folded fabrics. Recently, these deformations are being pursued for fabricating unique patterned surfaces. In this study, the transition from wrinkling, a low-strain buckling behavior, to localized deformations such as fold and delamination, is investigated for polystyrene films with thickness ranging from 5nm to 180nm. The thin films are attached to a uniaxially strained polydimethysiloxane substrate and the strain is released incrementally to apply increasing compressive strain to the attached film. The wavelength and the amplitude of local out-of-plane deformation are measured as global compression is increased to distinguish between wrinkling, folding, and delamination. The transition from wrinkling to strain localizing events is observed by tracking the statistics of amplitude distribution sampled across a large lateral area. A critical strain map is constructed to denote the strain regimes at which wrinkle, fold, and delamination occur. NSF-DMR 0907219.

  7. Mass Transfer in Amperometric Biosensors Based on Nanocomposite Thin Films of Redox Polymers and Oxidoreductases

    Directory of Open Access Journals (Sweden)

    Aleksandr L. Simonian

    2002-03-01

    Full Text Available Mass transfer in nanocomposite hydrogel thin films consisting of alternating layers of an organometallic redox polymer (RP and oxidoreductase enzymes was investigated. Multilayer nanostructures were fabricated on gold surfaces by the deposition of an anionic self-assembled monolayer of 11-mercaptoundecanoic acid, followed by the electrostatic binding of a cationic redox polymer, poly[vinylpyridine Os(bis-bipyridine2Clco-allylamine], and an anionic oxidoreductase. Surface plasmon resonance spectroscopy, Fourier transform infrared external reflection spectroscopy (FTIR-ERS, ellipsometry and electrochemistry were employed to characterize the assembly of these nanocomposite films. Simultaneous SPR/electrochemistry enabled real time observation of the assembly of sensing components, changes in film structure with electrode potential, and the immediate, in situ electrochemical verification of substrate-dependent current upon the addition of enzyme to the multilayer structure. SPR and FTIR-ERS studies also showed no desorption of polymer or enzyme from the nanocomposite structure when stored in aqueous environment occurred over the period of three weeks, suggesting that decreasing in substrate sensitivity were due to loss of enzymatic activity rather than loss of film compounds from the nanostructure.

  8. In-situ ATR-FTIR for characterization of thin biorelated polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Müller, M., E-mail: mamuller@ipfdd.de [Leibniz Institute of Polymer Research Dresden (IPF Dresden), Hohe Straße 6, 01069 Dresden (Germany); Technical University of Dresden (TUD), Department of Chemistry and Food Chemistry, 01062 Dresden (Germany); Torger, B. [Leibniz Institute of Polymer Research Dresden (IPF Dresden), Hohe Straße 6, 01069 Dresden (Germany); Technical University of Dresden (TUD), Department of Chemistry and Food Chemistry, 01062 Dresden (Germany); Bittrich, E. [Leibniz Institute of Polymer Research Dresden (IPF Dresden), Hohe Straße 6, 01069 Dresden (Germany); Kaul, E.; Ionov, L. [Leibniz Institute of Polymer Research Dresden (IPF Dresden), Hohe Straße 6, 01069 Dresden (Germany); Technical University of Dresden (TUD), Department of Chemistry and Food Chemistry, 01062 Dresden (Germany); Uhlmann, P. [Leibniz Institute of Polymer Research Dresden (IPF Dresden), Hohe Straße 6, 01069 Dresden (Germany); Stamm, M. [Leibniz Institute of Polymer Research Dresden (IPF Dresden), Hohe Straße 6, 01069 Dresden (Germany); Technical University of Dresden (TUD), Department of Chemistry and Food Chemistry, 01062 Dresden (Germany)

    2014-04-01

    We present and review in-situ-attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopic data from thin biorelated polymer films useful for the modification and functionalization of polymer and inorganic materials and discuss their applications related to life sciences. A special ATR mirror attachment operated by the single-beam-sample-reference (SBSR) concept and housing a homebuilt thermostatable flow cell was used, which allows for appropriate background compensation and signal to noise ratio. ATR-FTIR data on the reactive deposition of dopamine on inorganic model surfaces are shown. Information on the structure and deposition pathway for such bioinspired melanin-like films is provided. ATR-FTIR data on thermosensitive polymer brushes of poly(N-isopropylacrylamide) (PNIPAAM) is then presented. The thermotropic hydration and hydrogen bonding behavior of PNIPAAM brush films is described. Finally, ATR-FTIR data on biorelated polyelectrolyte multilayers (PEM) are given together with details on PEM growth and detection. Applications of these latter films for biopassivation/activation and local drug delivery are addressed.

  9. Polymer-Silica nanoparticles composite films as protective coatings for stone-based monuments

    Energy Technology Data Exchange (ETDEWEB)

    Manoudis, P [Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124, Thessaloniki (Greece); Papadopoulou, S [Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124, Thessaloniki (Greece); Karapanagiotis, I [' Ormylia' Art Diagnosis Centre, Ormylia, Chalkidiki, 63071 (Greece); Tsakalof, A [Medical Department, University of Thessaly, Larissa, 41222 (Greece); Zuburtikudis, I [Department of Industrial Design Engineering, TEI of Western Macedonia, Kozani, 50100 (Greece); Panayiotou, C [Department of Chemical Engineering, Aristotle University of Thessaloniki, 54124, Thessaloniki (Greece)

    2007-04-15

    The decrease of surface energy of mineral substrates similar to those used in many stone monuments of cultural heritage by the application of protective polymer coatings along with the simultaneous increase of their surface roughness can increase their ability to repel water substantially. In this work, the effect of artificially induced roughness on the water repellency of mineral substrates coated with protective polymer films was investigated. Natural marble samples or home made calcium carbonate blocks were tried as the mineral substrates. The roughness increase was achieved by mineral chemical etching or by creation of nanoscale binary composition film on the substrate surface. PMMA and PFPE were the polymers used, while different-sized silica nanoparticles were employed for the production of the nanocomposite films. Examination of the coated and uncoated surfaces with profilometry and AFM and measurements of water contact angles reveal a pronounced effect of the surface roughness on water repellency. Especially in the case of nanocomposite coatings, the surfaces become super-hydrophobic. This result indicates that the nanoscale binary composition film scheme, which is characterized by its simplicity and low cost, is a suitable candidate for the water protection of stone-based monuments on large scale.

  10. Polymer-Carbon Nanotube Composite Films at the Oil/Water Interface: Assembly and Properties

    Science.gov (United States)

    Hoagland, David; Feng, Tao; Russell, Thomas P.

    2015-03-01

    Efficient carbon nanotube assembly at the oil/water interface was achieved by dissolving cationic polymers in the oil phase and oxidized nanotubes in the water phase, the two components spontaneously forming salt bridges to produce a composite interfacial film of nanoscopic thickness. As seen by pendant drop tensiometry, parameters such as carbon nanotube and polymer concentration, pH, polymer molecular weight, and degree of nanotube oxidation all affect assembly strongly, with measured trends to be described and explained. The frequency-dependent elastic and viscous moduli of films in dilation were characterized by interfacial pendant drop rheology. Structural (fast, minutes) and adsorption/desorption (slow, tens of minutes) relaxations were both noted, and at frequencies intermediate to the two, almost insensitive to assembly parameters, the films displayed expected behaviors for 2D critical gels, i.e., at the crossover between fluid and solid. Tan(delta) was frequency-independent over one to two decades of frequency, and the modulus of linear stress relaxation was a power law in time. Films wrinkled by larger (nonlinear) strains recovered over the structural relaxation time. Support: NSF-sponsored UMass MRSEC and the US DoE Office of Basic Energy Science through Contract DE-FG02-04ER46126.

  11. SAXS Studies of TiO2 Nanoparticles in Polymer Electrolytes and in Nanostructured Films

    Directory of Open Access Journals (Sweden)

    Sigrid Bernstorff

    2010-11-01

    Full Text Available Polymer electrolytes as nanostructured materials are very attractive components for batteries and opto-electronic devices. (PEO8ZnCl2 polymer electrolytes were prepared from PEO and ZnCl2. The nanocomposites (PEO8ZnCl2/TiO2 themselves contained TiO2 nanograins. In this work, the influence of the TiO2 nanograins on the morphology and ionic conductivity of the nanocomposite was systematically studied by transmission small-angle X-ray scattering (SAXS simultaneously recorded with wide-angle X-ray diffraction (WAXD and differential scanning calorimetry (DSC at the synchrotron ELETTRA. Films containing nanosized grains of titanium dioxide (TiO2 are widely used in the research of optical and photovoltaic devices. The TiO2 films, prepared by chemical vapor deposition and e-beam epitaxy, were annealed in hydrogen atmospheres in the temperature range between 20 °C and 900 °C in order to study anatase-rutile phase transition at 740 °C. Also, grazing-incidence small angle X-ray scattering (GISAXS spectra for each TiO2 film were measured in reflection geometry at different grazing incident angles. Environmentally friendly galvanic cells, as well as solar cells of the second generation, are to be constructed with TiO2 film as working electrode, and nanocomposite polymer as electrolyte.

  12. Gate-induced superconductivity in a solution-processed organic polymer film.

    Science.gov (United States)

    Schön, J H; Dodabalapur, A; Bao, Z; Kloc, C; Schenker, O; Batlogg, B

    2001-03-08

    The electrical and optical properties of conjugated polymers have received considerable attention in the context of potentially low-cost replacements for conventional metals and inorganic semiconductors. Charge transport in these organic materials has been characterized in both the doped-metallic and the semiconducting state, but superconductivity has not hitherto been observed in these polymers. Here we report a distinct metal-insulator transition and metallic levels of conductivity in a polymer field-effect transistor. The active material is solution-cast regioregular poly(3-hexylthiophene), which forms relatively well ordered films owing to self-organization, and which yields a high charge carrier mobility (0.05-0.1 cm2 V(-1) s(-1)) at room temperature. At temperatures below approximately 2.35 K with sheet carrier densities exceeding 2.5 x 10(14) cm(-2), the polythiophene film becomes superconducting. The appearance of superconductivity seems to be closely related to the self-assembly properties of the polymer, as the introduction of additional disorder is found to suppress superconductivity. Our findings therefore demonstrate the feasibility of tuning the electrical properties of conjugated polymers over the largest range possible-from insulating to superconducting.

  13. Polymer multilayer films obtained by electrochemically catalyzed click chemistry.

    Science.gov (United States)

    Rydzek, Gaulthier; Thomann, Jean-Sébastien; Ben Ameur, Nejla; Jierry, Loïc; Mésini, Philippe; Ponche, Arnaud; Contal, Christophe; El Haitami, Alae E; Voegel, Jean-Claude; Senger, Bernard; Schaaf, Pierre; Frisch, Benoît; Boulmedais, Fouzia

    2010-02-16

    We report the covalent layer-by-layer construction of polyelectrolyte multilayer (PEM) films by using an efficient electrochemically triggered Sharpless click reaction. The click reaction is catalyzed by Cu(I) which is generated in situ from Cu(II) (originating from the dissolution of CuSO(4)) at the electrode constituting the substrate of the film. The film buildup can be controlled by the application of a mild potential inducing the reduction of Cu(II) to Cu(I) in the absence of any reducing agent or any ligand. The experiments were carried out in an electrochemical quartz crystal microbalance cell which allows both to apply a controlled potential on a gold electrode and to follow the mass deposited on the electrode through the quartz crystal microbalance. Poly(acrylic acid) (PAA) modified with either alkyne (PAA(Alk)) or azide (PAA(Az)) functions grafted onto the PAA backbone through ethylene glycol arms were used to build the PEM films. Construction takes place on gold electrodes whose potentials are more negative than a critical value, which lies between -70 and -150 mV vs Ag/AgCl (KCl sat.) reference electrode. The film thickness increment per bilayer appears independent of the applied voltage as long as it is more negative than the critical potential, but it depends upon Cu(II) and polyelectrolyte concentrations in solution and upon the reduction time of Cu(II) during each deposition step. An increase of any of these latter parameters leads to an increase of the mass deposited per layer. For given buildup conditions, the construction levels off after a given number of deposition steps which increases with the Cu(II) concentration and/or the Cu(II) reduction time. A model based on the diffusion of Cu(II) and Cu(I) ions through the film and the dynamics of the polyelectrolyte anchoring on the film, during the reduction period of Cu(II), is proposed to explain the major buildup features.

  14. High proton conductivity in the molecular interlayer of a polymer nanosheet multilayer film.

    Science.gov (United States)

    Sato, Takuma; Hayasaka, Yuta; Mitsuishi, Masaya; Miyashita, Tokuji; Nagano, Shusaku; Matsui, Jun

    2015-05-12

    High proton conductivity was achieved in a polymer multilayer film with a well-defined two-dimensional lamella structure. The multilayer film was prepared by deposition of poly(N-dodecylacryamide-co-acrylic acid) (p(DDA/AA)) monolayers onto a solid substrate using the Langmuir-Blodgett technique. Grazing-angle incidence X-ray diffraction measurement of a 30-layer film of p(DDA/AA) showed strong diffraction peaks in the out-of-plane direction at 2θ = 2.26° and 4.50°, revealing that the multilayer film had a highly uniform layered structure with a monolayer thickness of 2.0 nm. The proton conductivity of the p(DDA/AA) multilayer film parallel to the layer plane direction was 0.051 S/cm at 60 °C and 98% relative humidity with a low activation energy of 0.35 eV, which is comparable to perfluorosulfonic acid membranes. The high conductivity and low activation energy resulted from the formation of uniform two-dimensional proton-conductive nanochannels in the hydrophilic regions of the multilayer film. The proton conductivity of the multilayer film perpendicular to the layer plane was determined to be 2.1 × 10(-13) S/cm. Therefore, the multilayer film showed large anisotropic conductivity with an anisotropic ratio of 2.4 × 10(11).

  15. Non-Vacuum Processed Polymer Composite Antireflection Coating Films for Silicon Solar Cells

    Directory of Open Access Journals (Sweden)

    Abdullah Uzum

    2016-08-01

    Full Text Available A non-vacuum processing method for preparing polymer-based ZrO2/TiO2 multilayer structure antireflection coating (ARC films for crystalline silicon solar cells by spin coating is introduced. Initially, ZrO2, TiO2 and surface deactivated-TiO2 (SD-TiO2 based films were examined separately and the effect of photocatalytic properties of TiO2 film on the reflectivity on silicon surface was investigated. Degradation of the reflectance performance with increasing reflectivity of up to 2% in the ultraviolet region was confirmed. No significant change of the reflectance was observed when utilizing SD-TiO2 and ZrO2 films. Average reflectance (between 300 nm–1100 nm of the silicon surface coated with optimized polymer-based ZrO2 single or ZrO2/SD-TiO2 multilayer composite films was decreased down to 6.5% and 5.5%, respectively. Improvement of photocurrent density (Jsc and conversion efficiency (η of fabricated silicon solar cells owing to the ZrO2/SD-TiO2 multilayer ARC could be confirmed. The photovoltaic properties of Jsc, the open-circuit photo voltage (VOC, the fill factor (FF, and the η were 31.42 mA cm−2, 575 mV, 71.5% and 12.91%. Efficiency of the solar cells was improved by the ZrO2-polymer/SD-TiO2 polymer ARC composite layer by a factor of 0.8% with an increase of Jsc (2.07 mA cm−2 compared to those of fabricated without the ARC.

  16. Influence of metallic and semiconducting nanostructures on the optical properties of dye-doped polymer thin films

    Energy Technology Data Exchange (ETDEWEB)

    Enculescu, M., E-mail: mdatcu@infim.ro; Matei, E.

    2016-09-01

    Dye-doped polymer thin films were obtained by spin-coating of 8% polyvinylpyrrolidone (PVP) solutions (in ethanol). Ni or ZnO nanowires were incorporated in Rhodamine 6G doped polymer films (10{sup −4} M dye concentration). Optical and morphological properties of simple dye-doped polymer films and films containing metallic or semiconducting nanostructures were investigated. Optical microscopy and scanning electron microscopy were used to image the nanowires. The presence of Ni nanowires induces a small shift (2–3 nm) to longer wavelengths on the emission band of Rh 6G doped PVP film. The ZnO nanowires' presence was confirmed by X-ray diffraction measurements. An enhancement of the emission of the dye doped polymer is induced by the semiconducting structures. - Highlights: • Rhodamine 6G doped polyvinylpyrrolidone thin films were obtained by spin-coating. • Ni or ZnO nanowires were incorporated in Rhodamine 6G doped polymer films. • Ni nanowires' presence induces a shift to shorter wavelengths on the emission band. • Enhancement of dye-doped polymer emission induced by the semiconducting structures.

  17. Effect of plasticizer on surface of free films prepared from aqueous solutions of salts of cationic polymers with different plasticizers

    Science.gov (United States)

    Bajdik, János; Fehér, Máté; Pintye-Hódi, Klára

    2007-06-01

    Acquisition of a more detailed understanding of all technological processes is currently a relevant tendency in pharmaceutical technology and hence in industry. A knowledge of film formation from dispersion of polymers is very important during the coating of solid dosage forms. This process and the structure of the film can be influenced by different additives. In the present study, taste-masking films were prepared from aqueous citric acid solutions of a cationic polymer (Eudragit ® E PO) with various hydrophilic plasticizers (glycerol, propylene glycol and different poly(ethylene glycols)). The mechanical properties, film thickness, wetting properties and surface free energy of the free films were studied. The aim was to evaluate the properties of surface of free films to predict the arrangement of macromolecules in films formed from aqueous solutions of salts of cationic polymers. A high molecular weight of the plasticizer decreased the work of deformation. The surface free energy and the polarity were highest for the film without plasticizer; the hydrophilic additives decreased these parameters. The direction of the change in polarity (a hydrophilic component caused a decrease in the polarity) was unexpected. It can be explained by the change in orientation of the macromolecules, a hydrophobic surface being formed. Examination of the mechanical properties and film thickness can furnish additional results towards a knowledge of film formation by this not frequently applied type of polymer from aqueous solution.

  18. Synthesis of environmentally responsive organic materials by application of ion track holes in polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Omichi, Hideki; Yoshida, Masaru; Asano, Masaharu [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Katakai, Ryoichi; Spohr, R.; Vetter, J.

    1997-03-01

    Polymer films were irradiated by heavy ion beams and etched by a concentrated alkali solution to produce particle track membranes (PTMs). Then the PTMs were chemically modified by grafting such monomers as amino acid group containing methacryloyl and N-isopropylacrylamide the polymers of which are known as environmentally responsive hydrogels. The size of pores of the modified PTMs under different temperatures in water was followed by electron microscopy. The pore was controlled from an open state to a completely closed state by changing temperature. The conductivity through the membrane was measured by changing the temperature of the cell. (author)

  19. Organic thin film transistors with polymer brush gate dielectrics synthesized by atom transfer radical polymerization

    DEFF Research Database (Denmark)

    Pinto, J.C.; Whiting, G.L.; Khodabakhsh, S.

    2008-01-01

    , synthesized by atom transfer radical polymerization (ATRP), were used to fabricate low voltage OFETs with both evaporated pentacene and solution deposited poly(3-hexylthiophene). The semiconductor-dielectric interfaces in these systems were studied with a variety of methods including scanning force microscopy......Low operating voltage is an important requirement that must be met for industrial adoption of organic field-effect transistors (OFETs). We report here solution fabricated polymer brush gate insulators with good uniformity, low surface roughness and high capacitance. These ultra thin polymer films...

  20. Glass-to-Rubber Transition of Polymer Thin Films and Their Surface Dynamical Properties

    Institute of Scientific and Technical Information of China (English)

    X.P.Wang; H.F.Zhang; Xudong Xiao; Ophelia K.C.Tsui

    2000-01-01

    @@ Glass-to-rubber transition temperature, Tg' of polystyrene(PS) (Mw=500K, Mw/Mn=1.03)thin films (thickness, d= 100 to 2000 A) deposited on Si with native oxide was determined by variable angle spectroscopic ellipsometry(VASE. We observed that the Tg of the polymer films decreased monotonically as the film thickness was decreased. It had previously been proposed that this was due to a highly mobile surface rubbery layer that existed even well below Tg' We used atomic force microscopic(AFM)adhesion measurement as a direct probe to investigate the surface dynamical properties of the PS samples and a thin film ofpoly(tert-butyl acrylate) (PtBA) (Mw= 148K, Mw/Mn=17, and Tg bullk=50℃). By comparing the AFM results and those obtained from shear modulus measurements of a bulk sample, we found no enhancement in the molecular relaxation at the free surface of these samples.

  1. Chemical solution deposition of YBCO thin film by different polymer additives

    Energy Technology Data Exchange (ETDEWEB)

    Wang, W.T.; Li, G.; Pu, M.H.; Sun, R.P.; Zhou, H.M.; Zhang, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu 610031 (China); Zhang, H. [Department of Physics, Peking University, Beijing 100871 (China); Yang, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu 610031 (China); Cheng, C.H. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu 610031 (China); School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia); Zhao, Y. [Key Laboratory of Magnetic Levitation Technologies and Maglev Trains, Ministry of Education of China, Superconductivity R and D Center (SRDC), Mail Stop 165, Southwest Jiaotong University, Chengdu 610031 (China); School of Materials Science and Engineering, University of New South Wale, Sydney, 2052 NSW (Australia)], E-mail: yzhao@swjtu.edu.cn

    2008-09-15

    A polymer-assisted chemical solution deposition approach has been proposed for the preparation of YBCO thin film. Different additives like PVB (polyvinyl butyral), PEG (polyethylene glycol) and PVP (polyvinylpyrrolidone) have been used to adjust the final viscosity of the precursor solution and thus the film formation. In this fluorine-free approach, YBCO has been deposited on single crystal substrates with metal acetates being starting materials. Biaxially textured YBCO thin films have been obtained. However, different additives lead to different microstructure. Dense, smooth and crack-free YBCO film prepared with PVB as additive yields sharp superconducting transition around T{sub c} = 90 K as well as high J{sub c} (0 T, 77 K) over 3 MA/cm{sup 2}.

  2. Chemical solution deposition of YBCO thin film by different polymer additives

    Science.gov (United States)

    Wang, W. T.; Li, G.; Pu, M. H.; Sun, R. P.; Zhou, H. M.; Zhang, Y.; Zhang, H.; Yang, Y.; Cheng, C. H.; Zhao, Y.

    2008-09-01

    A polymer-assisted chemical solution deposition approach has been proposed for the preparation of YBCO thin film. Different additives like PVB (polyvinyl butyral), PEG (polyethylene glycol) and PVP (polyvinylpyrrolidone) have been used to adjust the final viscosity of the precursor solution and thus the film formation. In this fluorine-free approach, YBCO has been deposited on single crystal substrates with metal acetates being starting materials. Biaxially textured YBCO thin films have been obtained. However, different additives lead to different microstructure. Dense, smooth and crack-free YBCO film prepared with PVB as additive yields sharp superconducting transition around Tc = 90 K as well as high Jc (0 T, 77 K) over 3 MA/cm 2.

  3. Improved Adhesion of Gold Thin Films Evaporated on Polymer Resin: Applications for Sensing Surfaces and MEMS

    Directory of Open Access Journals (Sweden)

    Behrang Moazzez

    2013-05-01

    Full Text Available We present and analyze a method to improve the morphology and mechanical properties of gold thin films for use in optical sensors or other settings where good adhesion of gold to a substrate is of importance and where controlled topography/roughness is key. To improve the adhesion of thermally evaporated gold thin films, we introduce a gold deposition step on SU-8 photoresist prior to UV exposure but after the pre-bake step of SU-8 processing. Shrinkage and distribution of residual stresses, which occur during cross-linking of the SU-8 polymer layer in the post-exposure baking step, are responsible for the higher adhesion of the top gold film to the post-deposition cured SU-8 sublayer. The SU-8 underlayer can also be used to tune the resulting gold film morphology. Our promoter-free protocol is easily integrated with existing sensor microfabrication processes.

  4. Structure and interaction of polymer thin films with supercritical carbon dioxide

    Science.gov (United States)

    Sirard, Stephen Michael

    2003-06-01

    An understanding of colloid stability in CO2 as well as the interaction of CO2 with polymer thin films is necessary for the intelligent design of CO2-based processes for future materials applications. In-situ spectroscopic ellipsometry (SE) was used to measure the thickness and optical properties of nanoscale poly(dimethylsiloxane) (PDMS) and poly(methyl methacrylate) films exposed to compressed CO2 . Both the sorption and CO2-induced dilation of the thin films were measured simultaneously with SE and deviations between the thin films and the corresponding bulk films may be attributed to excess CO 2 at the free interface as well as the influence of film confinement and the compressible nature of CO2 on the orientation and mobility of the polymers. SE was also used to measure sorption equilibrium and kinetics and CO2-induced dilation of polyimide (6FDA-DAM:DABA 2:1) thin films to determine how a gas separation membrane's structure affects its susceptibility to CO2-induced plasticization. Both thermal annealing and chemical crosslinking reduced the polymer dilation to prevent large increases in the CO2 diffusion coefficient at high CO2 pressures. The CO2 permeability and polymer free volume strongly depend on the annealing temperature, and different effects are observed for the crosslinked and uncrosslinked membranes and for the thick and thin membranes. Neutron reflectivity (NR) and SE were used to characterize the structure of end-grafted d-PDMS brushes on SiOx wafers exposed to compressed CO2. NR revealed two distinct regions in the segment density profile as a function of distance from the surface. The thickness and volume fraction profiles for the brush change much more with solvent quality than has been seen in previous studies with incompressible solvents, due to the high asymmetry in the intermolecular interactions, as well as the large compressibility and free volume differences between the polymer segments and the solvent. Turbidity versus time measurements

  5. Structural and ionic conductivity behavior in hydroxypropylmethylcellulose (HPMC) polymer films complexed with sodium iodide (NaI)

    Science.gov (United States)

    Rani, N. Sandhya; Sannappa, J.; Demappa, T.; Mahadevaiah

    2013-02-01

    Solid polymer electrolyte films based on Hydroxypropylmethylcellulose (HPMC) complexed with Sodium Iodide (NaI) were prepared using solution cast method. The dissolution of the salt into the polymer host and the micro structural properties of pure and NaI complexed HPMC polymer electrolyte films were confirmed by X - Ray diffraction (XRD) studies. The XRD results revealed that the amorphous domains of HPMC polymer matrix was increased with increase in the NaI salt concentration. The degree of crystallanity and crystallite size is high for pure HPMC samples. Direct current (dc) conductivity was measured in the temperature range of 313-383k. Temperature dependence of dc electrical conductivity and activation energy regions data indicated the dominance of ion type charge transport in these polymer electrolyte films.

  6. INVESTIGATION OF SANITARY-HYGIENIC CHARACTERISTICS OF MULTILAYER POLYMER FILMS USED FOR VACUUM PACKAGING MODIFIED BY NATIVE ANTIMICROBIAL COMPONENTS

    Directory of Open Access Journals (Sweden)

    O. B. Fedotova

    2016-01-01

    Full Text Available The results of the research works related to investigation of sanitary-hygienic characteristics of multilayer polymer film materials where the inner layer contacting directly with food product is modified by native antimicrobial components.

  7. Development of polymer-bound fast-dissolving metformin buccal film with disintegrants

    Science.gov (United States)

    Haque, Shaikh Ershadul; Sheela, Angappan

    2015-01-01

    Fast-dissolving drug-delivery systems are considered advantageous over the existing conventional oral dosage forms like tablets, capsules, and syrups for being patient friendly. Buccal films are one such system responsible for systemic drug delivery at the desired site of action by avoiding hepatic first-pass metabolism. Metformin hydrochloride (Met), an antidiabetic drug, has poor bioavailability due to its high solubility and low permeability. The purpose of the study reported here was to develop a polymer-bound fast-dissolving buccal film of metformin to exploit these unique properties. In the study, metformin fast-dissolving films were prepared by the solvent-casting method using chitosan, a bioadhesive polymer. Further, starch, sodium starch glycolate, and microcrystalline cellulose were the disintegrants added to different ratios, forming various formulations (F1 to F7). The buccal films were evaluated for various parameters like weight variation, thickness, folding endurance, surface pH, content uniformity, tensile strength, and percentage of elongation. The films were also subjected to in vitro dissolution study, and the disintegration time was found to be less than 30 minutes for all formulations, which was attributed to the effect of disintegrants. Formulation F6 showed 92.2% drug release within 6 minutes due to the combined effect of sodium starch glycolate and microcrystalline cellulose. PMID:26491321

  8. Thin-film solid-state proton NMR measurements using a synthetic mica substrate: Polymer blends

    Science.gov (United States)

    VanderHart, David L.; Prabhu, Vivek M.; Lavery, Kristopher A.; Dennis, Cindi L.; Rao, Ashwin B.; Lin, Eric K.

    2009-11-01

    Solid-state proton nuclear magnetic resonance (NMR) measurements are performed successfully on polymer blend thin films through the use of synthetic mica as a substrate. When used as a substrate, synthetic fluorophlogopite mica with its proton-free, diamagnetic character, allows for adequate measurement sensitivity while minimally perturbing the proton thin-film spectra, especially relative to more commonly available natural micas. Specifically, we use multiple-pulse techniques in the presence of magic-angle spinning to measure the degree of mixing in two different polymer blend thin films, polystyrene/poly(xylylene ether) and poly(1-methyladamantyl methacrylate) (PMAdMA)/triphenylsulfonium perfluorobutanesulfonate (TPS-PFBS), spin-coated onto mica substrates. Our earlier studies had focused on bulk systems where NMR signals are stronger, but may not be representative of thin films of the same systems that are relevant to many applications such as photoresist formulations in the electronics industry. The superiority of synthetic over natural paramagnetic mica is demonstrated by the maintenance of resolution and spinning sideband intensities (relative to bulk samples) for the synthetic mica samples. In contrast, degraded resolution and large spinning sidebands are shown to typify spectra of the natural mica samples. This approach can be applied to many other proton measurements of solid thin films, thereby greatly extending the types of systems to be investigated. Magnetic susceptibility measurements are also reported for all micas used.

  9. Nanoscale investigations on interchain organization in thin films of polymer-liquid crystal blend

    Science.gov (United States)

    Villeneuve-Faure, C.; Le Borgne, D.; Ventalon, V.; Seguy, I.; Moineau-Chane Ching, K. I.; Bedel-Pereira, E.

    2017-07-01

    Optimized nanomorphology in organic thin active layers is crucial for good performance in organic solar cells. However, the relation between morphology and electronic properties at nanoscale remains not completely understood. Here, we study the effect of film thickness and temperature annealing on the ordering of poly(3-hexylthiophene) chains when the polymer is blended with a columnar liquid crystalline molecule. Electronic absorption, atomic force microscopy measurements, and Raman spectroscopy show that morphology and chain ordering of the blend depend on the film thickness. We highlight the benefit of using a liquid crystal in organic blends, opening the way to use simple processing methods for the fabrication of organic electronic devices.

  10. Characteristics of Electro-Optic Device Using Conducting Polymers, Polythiophene and Polypyrrole Films

    Science.gov (United States)

    Kaneto, Keiichi; Yoshino, Katsumi; Inuishi, Yoshio

    1983-07-01

    Detailed characteristics of electro-optic elements (color switching and memory) utilizing the spectral change of conducting polymers by electrochemical doping and undoping are studied. The response time of color switching, for example, red≤ftrightarrowblue in polythiophene film in the electrolyte of LiBF4/acetonitrile is 30˜100 msec under the applied voltages of -2.0{≤ftrightarrow}+4.0 V vs. Li plate. More than 103 cycles of color switch are observed quite reproducibly. Three color states of yellow green, dark brown and blue are demonstrated for polypyrrole film.

  11. Surface imprinted thin polymer film systems with selective recognition for bovine serum albumin.

    Science.gov (United States)

    Kryscio, David R; Peppas, Nicholas A

    2012-03-09

    Molecularly imprinted polymers are synthetic antibody mimics formed by the crosslinking of organic or inorganic polymers in the presence of an analyte which yields recognitive polymer networks with specific binding pockets for that biomolecule. Surface imprinted polymers were synthesized via a novel technique for the specific recognition of bovine serum albumin (BSA). Thin films of recognitive networks based on 2-(dimethylamino)ethyl methacrylate (DMAEMA) as the functional monomer and varying amounts of either N,N'-methylenebisacrylamide (MBA) or poly(ethylene glycol) (400) dimethacrylate (PEG400DMA) as the crosslinking agent were synthesized via UV free-radical polymerization and characterized. A clear and reproducible increase in recognition of the template BSA was demonstrated for these systems at 1.6-2.5 times more BSA recognized by the MIP sample relative to the control polymers. Additionally, these polymers exhibited selective recognition of the template relative to competing proteins with up to 2.9 times more BSA adsorbed than either glucose oxidase or bovine hemoglobin. These synthetic antibody mimics hold significant promise as the next generation of robust recognition elements in a wide range of bioassay and biosensor applications.

  12. Relaxation in Thin Polymer Films Mapped across the Film Thickness by Astigmatic Single-Molecule Imaging

    KAUST Repository

    Oba, Tatsuya

    2012-06-19

    We have studied relaxation processes in thin supported films of poly(methyl acrylate) at the temperature corresponding to 13 K above the glass transition by monitoring the reorientation of single perylenediimide molecules doped into the films. The axial position of the dye molecules across the thickness of the film was determined with a resolution of 12 nm by analyzing astigmatic fluorescence images. The average relaxation times of the rotating molecules do not depend on the overall thickness of the film between 20 and 110 nm. The relaxation times also do not show any dependence on the axial position within the films for the film thickness between 70 and 110 nm. In addition to the rotating molecules we observed a fraction of spatially diffusing molecules and completely immobile molecules. These molecules indicate the presence of thin (<5 nm) high-mobility surface layer and low-mobility layer at the interface with the substrate. (Figure presented) © 2012 American Chemical Society.

  13. Polymer Light-Emitting Diode Prepared by Floating-Off Film-Transfer Technique

    KAUST Repository

    Park, Jihoon

    2015-12-22

    © 2015 Copyright Taylor & Francis Group, LLC. Floating-off film-transfer technique was used for the formation of semiconducting polymer multi-layers and the effect on the performance of polymer light-emitting diode (PLED) was studied. This method made it possible to avoid the solvent compatibility problem that was typically encountered in successive coating of polymeric multilayer by solution processing. F8BT and MEH-PPV were used for electron transporting layer (ETL) and for emissive layer, respectively. Current-voltage-luminance characteristics and luminescence efficiency results showed that the insertion of ETL by floating-off film-transfer technique followed by proper heat treatment resulted in a significant improvement in PLED operation due to its electron-transporting and hole-blocking abilities.

  14. Numerical Self-Consistent Field Theory of Flat and Curved Polymer Thin Films

    Science.gov (United States)

    Chantawansri, Tanya L.; Garcia-Cervera, Carlos J.; Ceniceros, Hector D.; Fredrickson, Glenn H.

    2008-03-01

    Using self-consistent field theory, we explore the numerical methods and boundary conditions involved in modeling the self-assembly of inhomogeneous polymer thin films deposited on flat and curved substrates. The model is simulated using a fourth-order accurate spectral collocation method first used by Cochran et al. [Macromolecules 2006, 39, 2449-2451] to model bulk polymeric systems, but where we apply finite difference approximations and non-periodic boundary conditions for the film in the direction normal to the substrate. Boundary conditions are employed to model experimentally relevant substrate conditions such as a ``neutral'' or attractive bounding surface. For a neutral surface where the substrate has no preferential attraction to either polymer segment, it is appropriate to utilize Neumann boundary conditions, while a surface with a preferential attraction can be modeled using Robins or mixed boundary conditions.

  15. Molecular Water Lilies: Orienting Single Molecules in a Polymer Film by Solvent Vapor Annealing

    CERN Document Server

    Wuersch, Dominik; Eder, Theresa; Aggarwal, A Vikas; Idelson, Alissa; Hoeger, Sigurd; Lupton, John M; Vogelsang, Jan

    2016-01-01

    The microscopic orientation and position of photoactive molecules is crucial to the operation of optoelectronic devices such as OLEDs and solar cells. Here, we introduce a shape-persistent macrocyclic molecule as an excellent fluorescent probe to simply measure (i) its orientation by rotating the excitation polarization and recording the strength of modulation in photoluminescence (PL), and (ii) its position in a film by analyzing the overall PL brightness at the molecular level. The unique shape, the absorption and the fluorescence properties of this probe yields information on molecular orientation and position. We control orientation and positioning of the probe in a polymer film by solvent vapor annealing (SVA). During the SVA process the molecules accumulate at the polymer/air interface, where they adopt a flat conformation, much like water lilies on the surface of a pond. The results are significant for OLED fabrication and single-molecule spectroscopy (SMS) in general.

  16. Studying the Performance of Conductive Polymer Films as Textile Electrodes for Electrical Bioimpedance Measurements

    Science.gov (United States)

    Cunico, F. J.; Marquez, J. C.; Hilke, H.; Skrifvars, M.; Seoane, F.

    2013-04-01

    With the goal of finding novel biocompatible materials suitable to replace silver in the manufacturing of textile electrodes for medical applications of electrical bioimpedance spectroscopy, three different polymeric materials have been investigated. Films have been prepared from different polymeric materials and custom bracelets have been confectioned with them. Tetrapolar total right side electrical bioimpedance spectroscopy (EBIS) measurements have been performed with polymer and with standard gel electrodes. The performance of the polymer films was compared against the performance of the gel electrodes. The results indicated that only the polypropylene 1380 could produce EBIS measurements but remarkably tainted with high frequency artefacts. The influence of the electrode mismatch, stray capacitances and large electrode polarization impedance are unclear and they need to be clarified with further studies. If sensorized garments could be made with such biocompatible polymeric materials the burden of considering textrodes class III devices could be avoided.

  17. PHOTOCHROMISM AND LUMINESCENCE OF DOPANT CHROMOPHORES THROUGH TWO-PHOTON IONIZATION IN POLYMER FILMS

    Institute of Scientific and Technical Information of China (English)

    Masahide Yamamoto; Hideo Ohkita; Shinzaburo Ito

    2001-01-01

    Two-photon ionization and recombination processes of an aromatic chromophore doped in polymer films were studied and the features of these processes were discussed in relation to photofunctional polymers. An aromatic molecule having low ionization potential, e.g., N,N,N',N'-tetramethyl-p-phenylene diamine doped in poly(methyl methacrylate)(PMMA) film was easily photoionized by intense laser light excitation, giving a colored radical cation (photochromism) and a trapped electron in PMMA matrix. As a reversed process, the radical cation recombined with the trapped electron, showing discoloration and emitting luminescence, either isothermal luminescence (ITL), or thermoluminescence (TL). In this report,ITL and TL through the charge recombination process were studied and the luminescence was suggested as a mean of the read-out of photorecording.

  18. Composite materials obtained by the ion-plasma sputtering of metal compound coatings on polymer films

    Science.gov (United States)

    Khlebnikov, Nikolai; Polyakov, Evgenii; Borisov, Sergei; Barashev, Nikolai; Biramov, Emir; Maltceva, Anastasia; Vereshchagin, Artem; Khartov, Stas; Voronin, Anton

    2016-01-01

    In this article, the principle and examples composite materials obtained by deposition of metal compound coatings on polymer film substrates by the ion-plasma sputtering method are presented. A synergistic effect is to obtain the materials with structural properties of the polymer substrate and the surface properties of the metal deposited coatings. The technology of sputtering of TiN coatings of various thicknesses on polyethylene terephthalate films is discussed. The obtained composites are characterized by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), atomic force microscopy (AFM), and scanning tunneling microscopy (STM) is shown. The examples of application of this method, such as receiving nanocomposite track membranes and flexible transparent electrodes, are considered.

  19. Orientation of azobenzene molecules in polymer films induced by all-optical poling

    Institute of Scientific and Technical Information of China (English)

    Xiaoxia Zhong(钟晓霞); Shouyu Luo(罗售余); Xiuqin Yu(虞秀琴); Qu Li(李劬); Yingli Chen(陈英礼); Yu Sui(隋郁); Jie Yin(印杰)

    2003-01-01

    A model of the alignment of azobenzene molecules in polymer film induced by all-optical poling is proposedand verified by experiment. We found that when the writing beams of frequencies ω and 2ω are both linearlypolarized with their polarization directions parallel to each other, azobenzene molecules tend to reorientto the direction perpendicular to the writing beams polarization. At the end of the writing process, moremolecules orient to the direction perpendicular to the writing beams polarization than those which orientto the parallel direction. The alignment of molecules parallel or perpendicular to the polarization of thewriting beams is characteristic of polarity or no polarity, respectively. The alignment of molecules alongthe polarization of writing beams results in the second order nonlinearity in the polymer film. Accordingto the model, a new method to improve the optical poling efficiency is put forward.

  20. Linear dichroism and optical anisotropy of silver nanoprisms in polymer films

    Science.gov (United States)

    Requena, S.; Doan, H.; Raut, S.; D'Achille, A.; Gryczynski, Z.; Gryczynski, I.; Strzhemechny, Y. M.

    2016-08-01

    We present optical studies of two different size distributions of silver triangular nanoprisms, one with a dipole resonance at 520 nm and the other with a dipole resonance at 650 nm, placed in different media. Significant wavelength-dependent depolarization of scattered light from the silver nanoprisms suspended in water indicates strong interference of multiple surface plasmon resonant modes in the same particle. We use this depolarization as a probe of light scattering by the nanoprisms in a lipid solution due to the rejection of a polarized background scattering. Also, the silver nanoprisms were embedded in a polyvinyl alcohol polymer matrix and oriented by stretching the polymer/nanoprism nanocomposite films. We observe significantly increased linear dichroism in the region associated with the plasmonic in-plane dipole mode upon stretching. Additionally, there is a weaker linear dichroism in the region associated with out-of-plane modes, which vanish in the extinction spectrum of the stretched nanocomposite film.

  1. Direct immobilization of antibodies on a new polymer film for fabricating an electrochemical impedance immunosensor.

    Science.gov (United States)

    Zhang, Xiangyang; Shen, Guangyu; Shen, Youming; Yin, Dan; Zhang, Chunxiang

    2015-09-15

    A new polymer bearing aldehyde groups was designed and synthesized by grafting 4-pyridinecarboxaldehyde onto poly(epichlorohydrin). Antibodies can be directly immobilized on the surface of the polymer film through the covalent bonding of aldehyde groups of the film with amino groups of antibodies. In this study, human immunoglobulin G (IgG) was used as a model analyte for the fabrication of an electrochemical impedance immunosensor. Using the proposed immunosensor, IgG in the range from 0.1 to 80 ng ml(-1) was detected with a detection limit of 0.07 ng ml(-1) (signal/noise [S/N]=3). In addition, the electrochemical impedance immunosensor displays good stability and reproducibility.

  2. Preparation and Characterization of Potentially Antimicrobial Polymer Films Containing Starch Nano- and Microparticles

    Directory of Open Access Journals (Sweden)

    Paulius Pavelas DANILOVAS

    2014-09-01

    Full Text Available The forming conditions of biodegradable polymer films containing iodine-modified starch particles as well as the properties of the obtained films were investigated. Cationic cross-linked starch microparticles and cationic starch nanoparticles were dispersed in cellulose acetate and hydroxyethyl cellulose solution, respectively, and composite films were spin-casted. The obtained films were characterized and their mechanical properties were assessed. The cellulose acetate solution has been found to be an appropriate matrix for the dispersion of dry modified starch microparticles, but not in the case of nanoparticles. Starch nanoparticles were obtained in an aqueous medium, and the mechanical properties of the formed cellulose acetate films are significantly reduced by water present in the casting solution. It has been estimated that a fairly high amount of nanoparticles (18 wt% can be immobilized into films of water-soluble hydroxyethyl cellulose without markedly affecting the mechanical properties of the films. DOI: http://dx.doi.org/10.5755/j01.ms.20.3.5426

  3. A molecular scale perspective: Monte Carlo simulation for rupturing of ultra thin polymer film melts

    Science.gov (United States)

    Singh, Satya Pal

    2017-04-01

    Monte Carlo simulation has been performed to study the rupturing process of thin polymer film under strong confinement. The change in mean square displacement; pair correlation function; density distribution; average bond length and microscopic viscosity are sampled by varying the molecular interaction parameters such as the strength and the equilibrium positions of the bonding, non-bonding potentials and the sizes of the beads. The variation in mean square angular displacement χθ = [ - 2 ] fits very well to a function of type y (t) = A + B *e-t/τ. This may help to study the viscous properties of the films and its dependence on different parameters. The ultra thin film annealed at high temperature gets ruptured and holes are created in the film mimicking spinodal dewetting. The pair correlation function and density profile reveal rich information about the equilibrium structure of the film. The strength and equilibrium bond length of finite extensible non-linear elastic potential (FENE) and non-bonding Morse potential have clear impact on microscopic rupturing of the film. The beads show Rouse or repetition motion forming rim like structures near the holes created inside the film. The higher order interaction as dipole-quadrupole may get prominence under strong confinement. The enhanced excluded volume interaction under strong confinement may overlap with the molecular dispersion forces. It can work to reorganize the molecules at the bottom of the scale and can imprint its signature in complex patterns evolved.

  4. Electron irradiation effects on partially fluorinated polymer films: Structure-property relationships

    CERN Document Server

    Nasef, M M

    2003-01-01

    The effects of electron beam irradiation on two partially fluorinated polymer films i.e. poly(vinylidene fluoride) (PVDF) and poly(ethylene-tetrafluoroethylene) copolymer (ETFE) are studied at doses ranging from 100 to 1200 kGy in air at room temperature. Chemical structure, thermal and mechanical properties of irradiated films are investigated. FTIR show that both PVDF and ETFE films undergo similar changes in their chemical structures including the formation of carbonyl groups and double bonding. The changes in melting and crystallisation temperatures (T sub m and T sub c) in both irradiated films are functions of irradiation dose and reflect the disorder in the chemical structure caused by the competition between crosslinking and chain scission. The heat of melting (DELTA H sub m) and the degree of crystallinity (X sub c) of PVDF films show no significant changes with the dose increase, whereas those of ETFE films are reduced rapidly after the first 100 kGy. The tensile strength of PVDF films is improved b...

  5. Tensile characteristics of metal nanoparticle films on flexible polymer substrates for printed electronics applications

    Science.gov (United States)

    Kim, Sanghyeok; Won, Sejeong; Sim, Gi-Dong; Park, Inkyu; Lee, Soon-Bok

    2013-03-01

    Metal nanoparticle solutions are widely used for the fabrication of printed electronic devices. The mechanical properties of the solution-processed metal nanoparticle thin films are very important for the robust and reliable operation of printed electronic devices. In this paper, we report the tensile characteristics of silver nanoparticle (Ag NP) thin films on flexible polymer substrates by observing the microstructures and measuring the electrical resistance under tensile strain. The effects of the annealing temperatures and periods of Ag NP thin films on their failure strains are explained with a microstructural investigation. The maximum failure strain for Ag NP thin film was 6.6% after initial sintering at 150 °C for 30 min. Thermal annealing at higher temperatures for longer periods resulted in a reduction of the maximum failure strain, presumably due to higher porosity and larger pore size. We also found that solution-processed Ag NP thin films have lower failure strains than those of electron beam evaporated Ag thin films due to their highly porous film morphologies.

  6. Polymer-based triphenyl tetrazolium chloride films for ultraviolet radiation monitoring

    Science.gov (United States)

    Ebraheem, S.; Abdel-Fattah, A. A.; Said, F. I.; Ali, Z. I.

    2000-02-01

    Ultraviolet (UV) radiation monitoring films were prepared from solutions of polymers (polyvinyl, alcohol, PVA, or polyvinyl butyral, PVB), containing triphenyl tetrazolium chloride dye (TTC). These films have a pronounced response to the main UV radiation spectral regions [UV-A (400-320 nm), UV-B (320-280 nm), and UV-C (280-180 nm)] showing different sensitivities. PVA/TTC film has its maximum sensitivity in the UV-A region, while PVB/TTC film has its maximum sensitivity in the UV-C region. Both films have almost the same sensitivity in the UV-B region. The radiation-induced colour change is analysed spectrophotometrically at the maximum of the visible absorption band peaking at 492 nm wavelength. The measurement uncertainty of estimating ultraviolet radiation energy incident per unit area on the films is found to be about 3.5% (1 σ). The study of the effect of radiance exposure, incident wavelength, and storage conditions have been carried out to characterise the use of these films for actinometric monitoring artificial ultraviolet radiation sources which are used for medical and industrial applications.

  7. Biodegradation and in vivo biocompatibility of rosin: a natural film-forming polymer.

    Science.gov (United States)

    Satturwar, Prashant M; Fulzele, Suniket V; Dorle, Avinash K

    2003-10-22

    The specific aim of the present study was to investigate the biodegradation and biocompatibility characteristics of rosin, a natural film-forming polymer. Both in vitro as well as in vivo methods were used for assessment of the same. The in vitro degradation of rosin films was followed in pH 7.4 phosphate buffered saline at 37 degrees C and in vivo by subdermal implantation in rats for up to 90 days. Initial biocompatibility was followed on postoperative days 7, 14, 21, and 28 by histological observations of the surrounding tissues around the implanted films. Poly (DL-lactic-co-glycolic acid) (PLGA) (50:50) was used as reference material for biocompatibility. Rate and extent of degradation were followed in terms of dry film weight loss, molecular weight (MW) decline, and surface morphological changes. Although the rate of in vitro degradation was slow, rosin-free films showed complete degradation between 60 and 90 days following subdermal implantation in rats. The films degraded following different rates, in vitro and in vivo, but the mechanism followed was primarily bulk degradation. Rosin films demonstrated inflammatory reactions similar to PLGA, indicative of good biocompatibility. Good biocompatibility comparable to PLGA is demonstrated by the absence of necrosis or abscess formation in the surrounding tissues. The study provides valuable insight, which may lead to new applications of rosin in the field of drug delivery.

  8. Composite thin film by hydrogen-bonding assembly of polymer brush and poly(vinylpyrrolidone).

    Science.gov (United States)

    Yang, Shuguang; Zhang, Yongjun; Wang, Li; Hong, Song; Xu, Jian; Chen, Yongming; Li, Chengming

    2006-01-03

    Based on hydrogen-bonding layer-by-layer (LBL) assembly in aqueous solution, poly(vinylpyrrolidone) (PVPON) and a spherical polymer brush with a poly(methylsilsesquioxane) (PSQ) core and poly(acrylic acid) (PAA) hair chains were used to fabricate composite multilayer thin films. Hydrogen bonding as the driving force was confirmed by FT-IR spectrometry. A simple method (Filmetric F20) was introduced to determine the thickness and refractive index of the films. The film thickness was found to be a linear function of the number of bilayers. The average increase in thickness per bilayer is 28.3 nm. The film morphology was characterized with scanning electron microscopy and atomic force microscopy. The images obtained from the two instruments show a great resemblance. The films were further calcined to get an inorganic film by removing the organic components, or treated with tetrabutylammonium fluoride (TBAF) to remove the PSQ core and get an organic film. The optical properties and morphological changes induced by these treatments were also studied.

  9. Tensile characteristics of metal nanoparticle films on flexible polymer substrates for printed electronics applications.

    Science.gov (United States)

    Kim, Sanghyeok; Won, Sejeong; Sim, Gi-Dong; Park, Inkyu; Lee, Soon-Bok

    2013-03-01

    Metal nanoparticle solutions are widely used for the fabrication of printed electronic devices. The mechanical properties of the solution-processed metal nanoparticle thin films are very important for the robust and reliable operation of printed electronic devices. In this paper, we report the tensile characteristics of silver nanoparticle (Ag NP) thin films on flexible polymer substrates by observing the microstructures and measuring the electrical resistance under tensile strain. The effects of the annealing temperatures and periods of Ag NP thin films on their failure strains are explained with a microstructural investigation. The maximum failure strain for Ag NP thin film was 6.6% after initial sintering at 150 °C for 30 min. Thermal annealing at higher temperatures for longer periods resulted in a reduction of the maximum failure strain, presumably due to higher porosity and larger pore size. We also found that solution-processed Ag NP thin films have lower failure strains than those of electron beam evaporated Ag thin films due to their highly porous film morphologies.

  10. Layer-by-layer structured polymer/TiO2 thin film and its gate dielectric application.

    Science.gov (United States)

    Park, Bong Jun; Park, Jae Hoon; Choi, Jong Sun; Choi, Hyoung Jin

    2010-07-01

    Composite materials of the polymer and inorganic dielectric material have been investigated due to synergistic effect of both flexible properties of the polymer and dielectric properties of the inorganic material. In this study, poly(methyl methacrylate-co-methacrylic acid)/titanium dioxide (PMMA-co-MAA/TiO2) bilayer films were fabricated using a spin coating method followed by a self assembled sol-gel process and then examined for a gate dielectric application of the OTFT. Fracture and surface morphologies of the bilayer film on silicon wafer was observed via both SEM and AFM. Dielectric constant of the composite film synthesized was found to be larger than that of pure polymer film. In addition, with pentacene as a conducting layer, device performance of the composite film was characterized, and it was found that the threshold gate voltage was reduced while the field induced current was increased.

  11. Structural characterization and thermally stimulated discharge conductivity (TSDC) study in polymer thin films

    Indian Academy of Sciences (India)

    V S Sangawar; R J Dhokne; A U Ubale; P S Chikhalikar; S D Meshram

    2007-04-01

    The electrical conductivity of naphthalene doped polystyrene (PS) films (≈ 61.58 m thick) was studied as a function of dopant concentration and temperature. The formation of charge transfer (CT) complexes and strong concentration dependence of carrier mobility point out that the current carriers are transported through doped polymer system via hopping among sites associated with the dopant molecules. The activation energy, a, was calculated from the graph of logvs 103/ plot within low and high temperature regions.

  12. Polymer-modified halide perovskite films for efficient and stable planar heterojunction solar cells

    Science.gov (United States)

    Zuo, Lijian; Guo, Hexia; deQuilettes, Dane W.; Jariwala, Sarthak; De Marco, Nicholas; Dong, Shiqi; DeBlock, Ryan; Ginger, David S.; Dunn, Bruce; Wang, Mingkui; Yang, Yang

    2017-01-01

    The solution processing of polycrystalline perovskite films introduces trap states that can adversely affect their optoelectronic properties. Motivated by the use of small-molecule surfactants to improve the optoelectronic performance of perovskites, we demonstrate the use of polymers with coordinating groups to improve the performance of solution-processed semiconductor films. The use of these polymer modifiers results in a marked change in the electronic properties of the films, as measured by both carrier dynamics and overall device performance. The devices grown with the polymer poly(4-vinylpyridine) (PVP) show significantly enhanced power conversion efficiency from 16.9 ± 0.7% to 18.8 ± 0.8% (champion efficiency, 20.2%) from a reverse scan and stabilized champion efficiency from 17.5 to 19.1% [under a bias of 0.94 V and AM (air mass) 1.5-G, 1-sun illumination over 30 min] compared to controls without any passivation. Treating the perovskite film with PVP enables a VOC of up to 1.16 V, which is among the best reported for a CH3NH3PbI3 perovskite solar cell and one of the lowest voltage deficits reported for any perovskite to date. In addition, perovskite solar cells treated with PVP show a long shelf lifetime of up to 90 days (retaining 85% of the initial efficiency) and increased by a factor of more than 20 compared to those without any polymer (degrading to 85% after ~4 days). Our work opens up a new class of chemical additives for improving perovskite performance and should pave the way toward improving perovskite solar cells for high efficiency and stability. PMID:28845446

  13. Investigation of Polymer Thick-film Piezoresistors for Medical Wrist Rehabilitation and Artificial Knee Load Sensors

    OpenAIRE

    2014-01-01

    Readily-available and low-cost commercial polymer-based composite materials, such as standard epoxy-fibreglass printed circuit board (PCB) substrates and resin-carbon thick-film piezoresistors, were evaluated as a solution for medical force sensors, such as a wrist rehabilitation device and an implantable wireless artificial knee force sensor. We show that such materials have high sensitivity, and sufficient short-term stability – provided careful mechanical design and materials selection are...

  14. Bias-stress-induced instability of polymer thin-film transistor based on poly(3-hexylthiophene)

    OpenAIRE

    Liu, YR; Liao, R.; Lai, PT; Yao, RH

    2012-01-01

    A polymer thin-film transistor (PTFT) based on poly(3-hexylthiophene) (P3HT) is fabricated by a spin-coating process and characterized. Its bias-stress-induced instability during operation is investigated as a function of time and temperature. For negative gate-bias stress, the carrier mobility remains unchanged, the off-state current decreases, and the threshold voltage shifts toward the negative direction. On the other hand, for negative drain-bias stress, the carrier mobility decreases sli...

  15. DNA-SMART: Biopatterned Polymer Film Microchannels for Selective Immobilization of Proteins and Cells.

    Science.gov (United States)

    Schneider, Ann-Kathrin; Nikolov, Pavel M; Giselbrecht, Stefan; Niemeyer, Christof M

    2017-02-22

    A novel SMART module, dubbed "DNA-SMART" (DNA substrate modification and replication by thermoforming) is reported, where polymer films are premodified with single-stranded DNA capture strands, microthermoformed into 3D structures, and postmodified with complementary DNA-protein conjugates to realize complex biologically active surfaces within microfluidic devices. As a proof of feasibility, it is demonstrated that microchannels presenting three different proteins on their inner curvilinear surface can be used for selective capture of cells under flow conditions.

  16. Stochastic model for photoinduced surface relief grating formation through molecular transport in polymer films.

    Energy Technology Data Exchange (ETDEWEB)

    Juan, M.; Plain, J.; Bachelot, R.; Royer, P.; Gray, S. K.; Wiederrecht, G. P.; Univ. de Technologie de Troyes

    2008-09-01

    We use a stochastic model to study photoinduced surface relief grating (SRG) formation due to molecular transport in azobenzene polymer films. The model is shown to reproduce the essential experimental features of SRG formation. In particular, it predicts SRG formation under both p and s polarizations, and the double peaked topographies that can occur at early times of the process. The evolving molecular positions and orientations during exposure are also followed, providing a useful mechanistic picture of SRG dynamics.

  17. Assessment of Femtosecond Laser Induced Periodic Surface Structures on Polymer Films

    OpenAIRE

    Rebollar, Esther; Vázquez De Aldana, Javier R.; Martín-Fabiani, Ignacio; Hernández, Margarita; Rueda, Daniel R.; Ezquerra, Tiberio A.; Domingo, Concepción; Moreno, Pablo; Castillejo, Marta

    2013-01-01

    In this work we present the formation of laser induced periodic surface structures (LIPSS) on spin-coated thin films of several model aromatic polymers including poly(ethylene terephthalate), poly(trimethylene terephthalate) and poly carbonate bis-phenol A upon irradiation with femtosecond pulses of 795 and 265 nm at fluences well below the ablation threshold. LIPSS are formed with period lengths similar to the laser wavelength and parallel to the direction of the laser polarization vector. F...

  18. Structural and electrochemical characterisation of [Pd(salen)]-type conducting polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Fonseca, J. [REQUIMTE, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); Tedim, J. [Department of Chemistry, University of Leicester, Leicester LE1 7 RH (United Kingdom); Biernacki, K.; Magalhaes, A.L. [REQUIMTE, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); Gurman, S.J. [Department of Physics, University of Leicester, Leicester LE1 7 RH (United Kingdom); Freire, C., E-mail: acfreire@fc.up.p [REQUIMTE, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 4169-007 Porto (Portugal); Hillman, A.R., E-mail: arh7@le.ac.u [Department of Chemistry, University of Leicester, Leicester LE1 7 RH (United Kingdom)

    2010-11-01

    The oxidative polymerisation of four structurally-related [Pd(salen)] complexes and characterisation of the resulting polymeric films by cyclic voltammetry (CV), UV-visible transmission spectroscopy, X-ray absorption spectroscopy (XAS) and X-ray photoelectron spectroscopy (XPS) is reported. The voltammetric technique gives insight into the electrochemical properties of the polymeric films whereas UV-visible spectroscopy is used to characterise the electronic structure of Pd electroactive films, of particular relevance to the type of charge carriers. X-ray techniques (supported by density functional theory, DFT) provide information related to composition and structural features of [Pd(salen)] precursors and the resulting polymers. Characterisation of poly[Pd(salen)] films shows that the electrochemical response of these supramolecular systems is ligand-based and dependent upon substituents in the diimine bridge and aldehyde moieties. XAS measurements near the Pd K-edge demonstrate that polymerisation of the Pd complexes does not change the coordination sphere of the Pd centre; this is consistent with the coupling of monomers units via phenyl rings. As further evidence of ligand-based electrochemical responses, polymer doping does not impart any changes at the Pd centre or its coordination sphere. Compositional analysis by XPS confirms that C: Pd, N: Pd and O: Pd surface atomic ratios do not change significantly from monomer to undoped or doped polymer, except for small variations associated with incorporation of electrolyte and solvent upon polymerisation and polymer oxidation. Overall, the data provide a picture of a polyaromatic delocalised electroactive system, in which the metal atom plays a templating (rather than electroactive) role.

  19. THE ESTIMATION OF ORDERING DEGREE OF CORONA-POLED NONLINEAR OPTICAL POLYMER FILMS

    Institute of Scientific and Technical Information of China (English)

    YE Cheng; DONG Haiou; WANG Jiafu

    1992-01-01

    The investigation of electrochromic effect of corona-poled nonlinear optical polymer films is an effective method for the estimation of poling level and the selection of poling conditions. The poling electric field Ep and orientational order parameter φ, which are the important parameters to predict d33 of poled tilms, can be calculated by a simple operation from the number of red shift of charge transfer absorption band. The calculated results are in good agreement with the experimental data.

  20. Optical properties of self-organized gold nanorod-polymer hybrid films.

    Science.gov (United States)

    Tritschler, Ulrich; Zlotnikov, Igor; Keckeis, Philipp; Schlaad, Helmut; Cölfen, Helmut

    2014-11-25

    High fractions of gold nanorods were locally aligned by means of a polymeric liquid crystalline phase. The gold nanorods constituting >80 wt % of the thin organic-inorganic composite films form a network with side-by-side and end-to-end combinations. Organization into these network structures was induced by shearing gold nanorod-LC polymer dispersions via spin-coating. The LC polymer is a polyoxazoline functionalized with pendent cholesteryl and carboxyl side groups enabling the polymer to bind to the CTAB stabilizer layer of the gold nanorods via electrostatic interactions, thus forming the glue between organic and inorganic components, and to form a chiral nematic lyotropic phase. The self-assembled locally oriented gold nanorod structuring enables control over collective optical properties due to plasmon resonance coupling, reminiscent of enhanced optical properties of natural biomaterials.

  1. Interfacial design and structure of protein/polymer films on oxidized AlGaN surfaces

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Samit K; Casal, Patricia; Nicholson III, Theodore R; Lee, Stephen Craig [Department of Biomedical Engineering, Ohio State University, Columbus, OH 43210 (United States); Wu, Hao-Hsuan; Wen Xuejin; Anisha, R; Berger, Paul R; Lu, Wu; Brillson, Leonard J [Department of Electrical and Computer Engineering, Ohio State University, Columbus, OH 43210 (United States); Kwak, Kwang J; Bhushan, Bharat, E-mail: lee.1996@osu.edu [Department of Mechanical Engineering, Ohio State University, Columbus, OH 43210 (United States)

    2011-01-26

    Protein detection using biologically or immunologically modified field-effect transistors (bio/immunoFETs) depends on the nanoscale structure of the polymer/protein film at sensor interfaces (Bhushan 2010 Springer Handbook of Nanotechnology 3rd edn (Heidelberg: Springer); Gupta et al 2010 The effect of interface modification on bioFET sensitivity, submitted). AlGaN-based HFETs (heterojunction FETs) are attractive platforms for many protein sensing applications due to their electrical stability in high osmolarity aqueous environments and favourable current drive capabilities. However, interfacial polymer/protein films on AlGaN, though critical to HFET protein sensor function, have not yet been fully characterized. These interfacial films are typically comprised of protein-polymer films, in which analyte-specific receptors are tethered to the sensing surface with a heterobifunctional linker molecule (often a silane molecule). Here we provide insight into the structure and tribology of silane interfaces composed of one of two different silane monomers deposited on oxidized AlGaN, and other metal oxide surfaces. We demonstrate distinct morphologies and wear properties for the interfacial films, attributable to the specific chemistries of the silane monomers used in the films. For each specific silane monomer, film morphologies and wear are broadly consistent on multiple oxide surfaces. Differences in interfacial film morphology also drive improvements in sensitivity of the underlying HFET (coincident with, though not necessarily caused by, differences in interfacial film thickness). We present a testable model of the hypothetical differential interfacial depth distribution of protein analytes on FET sensor interfaces with distinct morphologies. Empirical validation of this model may rationalize the actual behaviour of planar immunoFETs, which has been shown to be contrary to expectations of bio/immunoFET behaviour prevalent in the literature for the last 20 years

  2. Nanoparticles Stabilize Thin Polymer Films: A Fundamental Study to Understand the Phenomenon

    Energy Technology Data Exchange (ETDEWEB)

    Michael E. Mackay

    2009-03-04

    A new understanding of thermodynamics at the nanoscale resulted in a recently discovered first order phase transition that nanoparticles in a polymer film will all segregate to the supporting substrate. This is an unusual phase transition that was predicted using a modeling technique developed at Sandia National Laboratories and required the equivalent of many computational years on one computer. This project is a collaboration between Prof. Michael Mackay's group and Dr. Amalie Frischknecht (Sandia National Laboratories) where experimental observation and theoretical rationalization and prediction are brought together. Other discoveries were that this phase transition could be avoided by changing the nanoparticle properties yielding control of the assembly process at the nanoscale. In fact, the nanoparticles could be made to assemble to the supporting substrate, to the air interface or not assemble at all within a thin polymer film of order 100 nm in thickness. However, when the assembly process is present it is so robust that it is possible to make rough liquid films at the nanoscale due to nanoparticles assembling around three-dimensional objects. From this knowledge we are able to design and manufacture new coatings with particular emphasis on polymer-based solar cells. Careful control of the morphology at the nanoscale is expected to provide more efficient devices since the physics of these systems is dictated at this length scale and assembly of nanoparticles to various interfaces is critical to operation.

  3. Programming Surface Energy Driven Marangoni Convection in Polymer Thin Films to Generate Topographic Patterns

    Science.gov (United States)

    Kim, Chae Bin; Janes, Dustin; Arshad, Talha; Katzenstein, Joshua; Prisco, Nathan; McGuffin, Dana; Bonnecaze, Roger; Ellison, Christopher

    2015-03-01

    The Marangoni effect describes how fluid flows in response to gradients in surface energy. We recently developed a method for photochemically preprograming spatial surface energy patterns in glassy polystyrene (PS) thin films. UV irradiation through a mask selectively dehydrogenates the PS, thus increasing surface energy in the UV exposed regions compared to the unexposed regions. After heating the film to the liquid state, transport of polymer occurs from regions of low surface energy to regions of high surface energy. This method can be harnessed to rapidly manufacture polymer films possessing prescribed three-dimensional topographies reflective of the original light exposure pattern. To quantify and verify this phenomenon, a theoretical model that gives a more thorough understanding of the physics of this process, its limits and ways to apply it efficiently for various target metrics will also be presented along with comparisons between theoretical predictions and experimental observations. Finally, while PS dehydrogenation can be used to produce a variety of topographical patterns, judicious selection of the photosensitizing compounds in an otherwise transparent polymer expands the use of this method to more readily available light sources.

  4. Structural studies of thin films of semiconducting nanoparticles in polymer matrices

    Energy Technology Data Exchange (ETDEWEB)

    Di Luccio, Tiziana [ENEA, Centro Ricerche Brindisi, SS7 Appia Km 706, I-72100 Brindisi (Italy)], E-mail: tiziana.diluccio@portici.enea.it; Piscopiello, Emanuela; Laera, Anna Maria [ENEA, Centro Ricerche Brindisi, SS7 Appia Km 706, I-72100 Brindisi (Italy); Antisari, Marco Vittori [ENEA, Centro Ricerche Casaccia, Via Anguillarese 301, I-00060 S. Maria di Galeria (Roma) (Italy)

    2007-09-15

    Ordered films of nanoscale materials are issue of wide interest for applications in several fields, such as optics, catalysis, and bioelectronics. In particular, semiconducting nanoparticles incorporation in a processable polymer film is an easy way to manipulate such materials for their application. We deposited thin layers of cadmium sulphide (CdS) and zinc sulphide (ZnS) nanoparticles embedded in a thermoplastic cyclo-olephin copolymer (COC) with elevated optical transparency and highly bio-compatible. The nanoparticles were obtained by thiolate precursors previously dispersed in the polymer upon thermal treatment at temperatures ranging between 200 and 300 deg. C depending on the desired size. The precursor/polymer solutions were spin-coated in order to get thin films. The spinning conditions were changed in order to optimise the layer thickness and uniformity. The samples were mainly characterised by X-ray reflectivity (XRR) and by high-resolution transmission electron microscopy (HRTEM) analyses. The thinnest layer we have deposited is 8 nm thick, as evaluated by XRR. The HRTEM measurements showed that the nanoparticles have quasi-spherical shape without evident microstructural defects. The size of the nanoparticles depends on the annealing temperature, e.g. at 232 deg. C the size of the CdS nanoparticles is about 4-5 nm.

  5. Ambient low temperature plasma etching of polymer films for secondary ion mass spectrometry molecular depth profiling.

    Science.gov (United States)

    Muramoto, Shin; Staymates, Matthew E; Brewer, Tim M; Gillen, Greg

    2012-12-18

    The feasibility of a low temperature plasma (LTP) probe as a way to prepare polymer bevel cross sections for secondary ion mass spectrometry (SIMS) applications was investigated. Poly(lactic acid) and poly(methyl methacrylate) films were etched using He LTP, and the resulting crater walls were depth profiled using time-of-flight secondary ion mass spectrometry (ToF-SIMS) to examine changes in chemistry over the depth of the film. ToF-SIMS results showed that while exposure to even 1 s of plasma resulted in integration of atmospheric nitrogen and contaminants to the newly exposed surface, the actual chemical modification to the polymer backbone was found to be chemistry-dependent. For PLA, sample modification was confined to the top 15 nm of the PLA surface regardless of plasma exposure dose, while measurable change was not seen for PMMA. The confinement of chemical modification to 15 nm or less of the top surface suggests that LTP can be used as a simple method to prepare cross sections or bevels of polymer thin films for subsequent analysis by surface-sensitive molecular depth profiling techniques such as SIMS, X-ray photoelectron spectroscopy (XPS), and other spatially resolved mass spectrometric techniques.

  6. Enhanced anisotropy of gold nanorods-polymer composite films for optical applications

    Science.gov (United States)

    Stoenescu, Stefan; Badilescu, Simona; Packirisamy, Muthukumaran; Truong, Vo-Van

    2012-10-01

    The strong optical absorption, scattering and local electric field enhancement associated with the longitudinal Surface Plasmon Resonance (SPR) of gold nanorods (AuNRs) have important applications in imaging, sensing, nonlinear optics, thermal therapy and data encoding. The longitudinal SPR mode can be optimally excited only in the NRs that are most aligned with the electric field of a linearly polarized incident light. Thus, in cast polymer based nanorod composite films, where the NRs orientation is random, only a fraction of the embedded NRs is actually usable to the maximal extent for the intended applications. To enhance the degree of alignment of the AuNRs by uniaxial stretching and increase the application efficiency, we have improved the polymer matrix with respect to plastic deformation and designed a suitable drawing device to reduce the fracture risks of the polymer. The resulting nanocomposite film was characterized by Scanning Electron Microscopy (SEM) and by spectroscopy using linearly polarized light in the UV-Visible range. The linear dichroic ratio of the stretched nanocomposite film was calculated based on the ratio of the peak absorbance of the incident light parallelly polarized, to that of the light polarized perpendicularly to the NRs long axes.

  7. Optical behavior of silver nanoparticles embedded in polymer thin film layers

    Science.gov (United States)

    Carlberg, M.; Pourcin, F.; Margeat, O.; Le Rouzo, J.; Berginc, G.; Sauvage, R.-M.; Ackermann, J.; Escoubas, L.

    2016-09-01

    The study of metal nanoparticles (NPs) is challenging for the control of the light matter interaction phenomena. In this context, our work is focused on optical characterization and modeling of polymer thin films layers with inclusions of previously chemically synthesized NPs. Through the presence of metallic NPs in polymer thin films, the optical properties are assumed to become tunable. Thin film layers with inclusions of differently shaped and sized silver NPs, such as nanospheres and nanoprisms, are optically characterized to get the scattering, the reflection and the absorption of the layers. One step and two step seed based methods of silver ions reduction are used for the chemical synthesis of nanospheres and nanoprisms. The plasmonic resonance peaks of these colloidal solutions range from 360 to 1300 nm. A poly vinyl pyrrolidone (PVP) polymer matrix is chosen for its light non-absorbing and NP-stabilizing properties. Knowledge on the shape and size of the NPs embedded in the spin coated layers is obtained by transmission electron microscopy (TEM) imaging. The optical properties include spectrophotometry and spectroscopic ellipsometry (SE) measurements to get the reflectance, the transmittance, the absorptance and the optical indices n and k of the heterogeneous layers. A redshift in absorption is measured between deposited nanospheres and other shaped NPs. FDTD simulations allow calculation of far and near field properties. The visualization of the NP interactions and the electric field enhancement, on and around the NPs, are studied to improve the understanding of the far field properties.

  8. Synthesis and characterization of polymer-silica hybrid latexes and sol-gel-derived films

    Science.gov (United States)

    Petcu, Cristian; Purcar, Violeta; Ianchiş, Raluca; Spătaru, Cătălin-Ilie; Ghiurea, Marius; Nicolae, Cristian Andi; Stroescu, Hermine; Atanase, Leonard-Ionuţ; Frone, Adriana Nicoleta; Trică, Bogdan; Donescu, Dan

    2016-12-01

    Sol-gel derived organic-inorganic hybrid systems were obtained by applying alkaline-catalyzed co-hydrolysis and copolycondensation reactions of tetraethoxysilane (TEOS), methyltriethoxysilane (MTES), isobutyltriethoxysilane (IBTES), diethoxydimethylsilane (DMDES), and vinyltriethoxysilane (VTES), respectively, into a polymer latex functionalized with vinyltriethoxysilane (VTES). The properties of the latex hybrid materials were analyzed by FTIR, water contact angle, environmental scanning electron microscopy (ESEM), TEM and AFM analysis, respectively. FT-IR spectra confirmed that the chemical structures of the sol-gel derived organic-inorganic materials are changed as function of inorganic precursor and Sisbnd Osbnd Si networks are formed during the co-hydrolysis and copolycondensation reactions. The water contact angle on the sol-gel latex film containing TEOS + VTES increased to 135° ± 2 compared to 65° ± 5 for the blank latex, due VTES incorporation into latex material. TGA curves of hybrid sample modifies against neat polymer, the thermal stability being influenced by the presence of the inorganic partner. ESEM analysis showed that the latex hybrid films prepared with different inorganic precursors were formed and the Si-based polymers were distributed on the surface of the dried sol-gel hybrid films. TEM and AFM photos revealed that the latex emulsion morphology was modified due to the VTES incorporation into system.

  9. Analysis of Osteoblast Differentiation on Polymer Thin Films Embedded with Carbon Nanotubes.

    Directory of Open Access Journals (Sweden)

    Jin Woo Lee

    Full Text Available Osteoblast differentiation can be modulated by variations in order of nanoscale topography. Biopolymers embedded with carbon nanotubes can cause various orders of roughness at the nanoscale and can be used to investigate the dynamics of extracellular matrix interaction with cells. In this study, clear relationship between the response of osteoblasts to integrin receptor activation, their phenotype, and transcription of certain genes on polymer composites embedded with carbon nanotubes was demonstrated. We generated an ultrathin nanocomposite film embedded with carbon nanotubes and observed improved adhesion of pre-osteoblasts, with a subsequent increase in their proliferation. The expression of genes encoding integrin subunits α5, αv, β1, and β3 was significantly upregulated at the early of time-point when cells initially attached to the carbon nanotube/polymer composite. The advantage of ultrathin nanocomposite film for pre-osteoblasts was demonstrated by staining for the cytoskeletal protein vinculin and cell nuclei. The expression of essential transcription factors for osteoblastogenesis, such as Runx2 and Sp7 transcription factor 7 (known as osterix, was upregulated after 7 days. Consequently, the expression of genes that determine osteoblast phenotype, such as alkaline phosphatase, type I collagen, and osteocalcin, was accelerated on carbon nanotube embedded polymer matrix after 14 days. In conclusion, the ultrathin nanocomposite film generated various orders of nanoscale topography that triggered processes related to osteoblast bone formation.

  10. Analysis of Osteoblast Differentiation on Polymer Thin Films Embedded with Carbon Nanotubes.

    Science.gov (United States)

    Lee, Jin Woo; Park, Jin-Woo; Khang, Dongwoo

    2015-01-01

    Osteoblast differentiation can be modulated by variations in order of nanoscale topography. Biopolymers embedded with carbon nanotubes can cause various orders of roughness at the nanoscale and can be used to investigate the dynamics of extracellular matrix interaction with cells. In this study, clear relationship between the response of osteoblasts to integrin receptor activation, their phenotype, and transcription of certain genes on polymer composites embedded with carbon nanotubes was demonstrated. We generated an ultrathin nanocomposite film embedded with carbon nanotubes and observed improved adhesion of pre-osteoblasts, with a subsequent increase in their proliferation. The expression of genes encoding integrin subunits α5, αv, β1, and β3 was significantly upregulated at the early of time-point when cells initially attached to the carbon nanotube/polymer composite. The advantage of ultrathin nanocomposite film for pre-osteoblasts was demonstrated by staining for the cytoskeletal protein vinculin and cell nuclei. The expression of essential transcription factors for osteoblastogenesis, such as Runx2 and Sp7 transcription factor 7 (known as osterix), was upregulated after 7 days. Consequently, the expression of genes that determine osteoblast phenotype, such as alkaline phosphatase, type I collagen, and osteocalcin, was accelerated on carbon nanotube embedded polymer matrix after 14 days. In conclusion, the ultrathin nanocomposite film generated various orders of nanoscale topography that triggered processes related to osteoblast bone formation.

  11. Development of biodegradable metaloxide/polymer nanocomposite films based on poly-ε-caprolactone and terephthalic acid.

    Science.gov (United States)

    Varaprasad, Kokkarachedu; Pariguana, Manuel; Raghavendra, Gownolla Malegowd; Jayaramudu, Tippabattini; Sadiku, Emmanuel Rotimi

    2017-01-01

    The present investigation describes the development of metal-oxide polymer nanocomposite films from biodegradable poly-ε-caprolactone, disposed poly(ethylene terephthalate) oil bottles monomer and zinc oxide-copper oxide nanoparticles. The terephthalic acid and zinc oxide-copper oxide nanoparticles were synthesized by using a temperature-dependent precipitation technique and double precipitation method, respectively. The terephthalic acid synthesized was confirmed by FTIR analysis and furthermore, it was characterized by thermal analysis. The as-prepared CuO-ZnO nanoparticles structure was confirmed by XRD analysis and its morphology was analyzed by SEM/EDS and TEM. Furthermore, the metal-oxide polymer nanocomposite films have excellent mechanical properties, with tensile strength and modulus better than pure films. The metal-oxide polymer nanocomposite films that were successfully developed show a relatively brighter colour when compared to CuO film. These new metal-oxide polymer nanocomposite films can replace many non-degradable plastics. The new metal-oxide polymer nanocomposite films developed are envisaged to be suitable for use in industrial and domestic packaging applications.

  12. Vacuum-integrated electrospray deposition for highly reliable polymer thin film.

    Science.gov (United States)

    Park, Soohyung; Lee, Younjoo; Yi, Yeonjin

    2012-10-01

    Vacuum electrospray deposition (ESD) equipment was designed to prepare polymer thin films. The polymer solution can be injected directly into vacuum system through multi-stage pumping line, so that the solvent residues and ambient contaminants are highly reduced. To test the performance of ESD system, we fabricated organic photovoltaic cells (OPVCs) by injecting polymer solution directly onto the substrate inside a high vacuum chamber. The OPVC fabricated has the structure of Al∕P3HT:PCBM∕PEDOT:PSS∕ITO and was optimized by varying the speed of solution injection and concentration of the solution. The power conversion efficiency (PCE) of the optimized OPVC is 3.14% under AM 1.5G irradiation without any buffer layer at the cathode side. To test the advantages of the vacuum ESD, we exposed the device to atmosphere between the deposition steps of the active layer and cathode. This showed that the PCE of the vacuum processed device is 24% higher than that of the air exposed device and confirms the advantages of the vacuum prepared polymer film for high performance devices.

  13. Computerized Stokes analysis of optically active polymer films

    CERN Document Server

    Georgiev, Georgi

    2010-01-01

    Optics labs are an integral part of the advanced curriculum for physics majors. Students majoring in other disciplines, like chemistry, biology or engineering rarely have the opportunity to learn about the most recent optical techniques and mathematical representation used in today’s science and industry optics. Stokes analysis of polarization of light is one of those methods that are increasingly necessary but are seldom taught outside advanced physics or optics classes that are limited to physics majors. On the other hand biology and chemistry majors already use matrix and polarization techniques in the labs for their specialty, which makes the transition to matrix calculations seamless. Since most of the students in those majors postpone their enrollment in physics, most of the registered in those classes are juniors and seniors, enabling them to handle those techniques. We chose to study polymer samples to aid students majoring in other disciplines, especially chemistry and engineering, with understa...

  14. Microanalysis of Ar and He bombarded biomedical polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Manso Silvan, M. [Departamento de Fisica Aplicada C-XII, Universidad Autonoma de Madrid, 28049 Madrid (Spain)]. E-mail: miguel.manso@uam.es; Gago, R. [Departamento de Fisica Aplicada C-XII, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Centro de Microanalisis de Materiales, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Valsesia, A. [European Commission, Institute for Health and Consumer Protection, Via Enrico Fermi, 21020 Ispra (Italy); Climent Font, A. [Departamento de Fisica Aplicada C-XII, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Centro de Microanalisis de Materiales, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Duart, J.M. Martinez [Departamento de Fisica Aplicada C-XII, Universidad Autonoma de Madrid, 28049 Madrid (Spain); Rossi, F. [European Commission, Institute for Health and Consumer Protection, Via Enrico Fermi, 21020 Ispra (Italy)

    2007-04-15

    Implantations onto polyethyleneglycol, polycaprolactone and polymethylmethacrylate, carried out with Ar and He ions at 25 and 100 KeV with fluences of 5 x 10{sup 13} cm{sup -2}, have been made with identical ion currents (20 {mu}A) but different sweep areas in order to take into account the effect of the ion flux on the composition and structure of these biopolymers. Vibrational (Fourier transformed infrared spectroscopy), microanalytical (Rutherford backscattering and energy recoil detection) and microscopic techniques (atomic force microscopy) confirm that, even in this low fluence regime, the ion flux effect is responsible of scaled modifications. More interestingly, these techniques indicate that the damage seems to be higher for He. All these factors suggest that He could be preferentially used to engineer biomedical polymers exploiting the tailoring opportunities offered by ion flux effects.

  15. Dynamic wetting on a thin film of soluble polymer: effects of nonlinearities in the sorption isotherm.

    Science.gov (United States)

    Dupas, Julien; Verneuil, Emilie; Ramaioli, Marco; Forny, Laurent; Talini, Laurence; Lequeux, Francois

    2013-10-08

    The wetting dynamics of a solvent on a soluble substrate interestingly results from the rates of the solvent transfers into the substrate. When a supported film of a hydrosoluble polymer with thickness e is wet by a spreading droplet of water with instantaneous velocity U, the contact angle is measured to be inversely proportionate to the product of thickness and velocity, eU, over two decades. As for many hydrosoluble polymers, the polymer we used (a polysaccharide) has a strongly nonlinear sorption isotherm φ(a(w)), where φ is the volume fraction of water in the polymer and aw is the activity of water. For the first time, this nonlinearity is accounted for in the dynamics of water uptake by the substrate. Indeed, by measuring the water content in the polymer around the droplet φ at distances as small as 5 μm, we find that the hydration profile exhibits (i) a strongly distorted shape that results directly from the nonlinearities of the sorption isotherm and (ii) a cutoff length ξ below which the water content in the substrate varies very slowly. The nonlinearities in the sorption isotherm and the hydration at small distances from the line were not accounted for by Tay et al., Soft Matter 2011, 7, 6953. Here, we develop a comprehensive description of the hydration of the substrate ahead of the contact line that encompasses the two water transfers at stake: (i) the evaporation-condensation process by which water transfers into the substrate through the atmosphere by the condensation of the vapor phase, which is fed by the evaporation from the droplet itself, and (ii) the diffusion of liquid water along the polymer film. We find that the eU rescaling of the contact angle arises from the evaporation-condensation process at small distances. We demonstrate why it is not modified by the second process.

  16. Thickness-Dependent Surfactant Behavior in Trilayer Polymer Films

    Science.gov (United States)

    Sun, Yan; Shull, Kenneth; Wang, Jin

    2010-03-01

    The ability for thin liquid films to wet and remain thermodynamically stable on top of one another is a fundamental challenge in developing high quality paints, coatings, adhesives, and other industrial products. Since intermolecular interactions and interfacial energies dominate in the film thickness regime from tens to hundreds of nanometers, it is desirable to tune these long-range and short-range forces in a simple, controllable manner. Starting from an unstable model homopolymer bilayer (poly(styrene)/poly(4-vinylpyridine)), we demonstrate that sandwiching an additional homopolymer layer (poly(4-bromostyrene)) between the two layers can provide needed surfactancy. As the thickness of this center layer is increased, the full trilayer transitions from unstable (thin) to stable (moderate) to unstable (thick). We experimentally show using x-ray standing waves generated via total external reflection (TER-XSW), atomic force microscopy (AFM), and time-of-flight secondary ion mass spectroscopy (ToF-SIMS) that this behavior can be directly attributed to the autophobic dewetting phenomenon, in which the surfactant layer is thin enough to remain stable but thick enough to shield the neighboring layers, highlighting a general approach to stabilizing multilayer systems.

  17. Interference of macroscopic superpositions

    CERN Document Server

    Vecchi, I

    2000-01-01

    We propose a simple experimental procedure based on the Elitzur-Vaidman scheme to implement a quantum nondemolition measurement testing the persistence of macroscopic superpositions. We conjecture that its implementation will reveal the persistence of superpositions of macroscopic objects in the absence of a direct act of observation.

  18. Chemical and microstructural characterizations of plasma polymer films by time-of-flight secondary ion mass spectrometry and principal component analysis

    Science.gov (United States)

    Cossement, Damien; Renaux, Fabian; Thiry, Damien; Ligot, Sylvie; Francq, Rémy; Snyders, Rony

    2015-11-01

    It is accepted that the macroscopic properties of functional plasma polymer films (PPF) are defined by their functional density and their crosslinking degree (χ) which are quantities that most of the time behave in opposite trends. If the PPF chemistry is relatively easy to evaluate, it is much more challenging for χ. This paper reviews the recent work developed in our group on the application of principal component analysis (PCA) to time-of-flight secondary ion mass spectrometric (ToF-SIMS) positive spectra data in order to extract the relative cross-linking degree (χ) of PPF. NH2-, COOR- and SH-containing PPF synthesized in our group by plasma enhanced chemical vapor deposition (PECVD) varying the applied radiofrequency power (PRF), have been used as model surfaces. For the three plasma polymer families, the scores of the first computed principal component (PC1) highlighted significant differences in the chemical composition supported by X-Ray photoelectron spectroscopy (XPS) data. The most important fragments contributing to PC1 (loadings > 90%) were used to compute an average C/H ratio index for samples synthesized at low and high PRF. This ratio being an evaluation of χ, these data, accordingly to the literature, indicates an increase of χ with PRF excepted for the SH-PPF. These results have been cross-checked by the evaluation of functional properties of the plasma polymers namely a linear correlation with the stability of NH2-PPF in ethanol and a correlation with the mechanical properties of the COOR-PPF. For the SH-PPF family, the peculiar evolution of χ is supported by the understanding of the growth mechanism of the PPF from plasma diagnostic. The whole set of data clearly demonstrates the potential of the PCA method for extracting information on the microstructure of plasma polymers from ToF-SIMS measurements.

  19. Thermal sensor properties of PANI(EB)–CSA ( = 0.4 ± 0.1 mol) polymer thin films

    Indian Academy of Sciences (India)

    T Prakash; S A K Narayan Dass; K Prem Nazeer

    2002-11-01

    Films of polyaniline(EB) doped with camphor sulfonic acid (CSA) from -cresol on glass substrates exhibit considerable metallic properties. Such polymer metallic films have thermal sensitivity superior to ceramic metal (Cermet) films, prepared by metallo organic deposition (MOD) technique on silicon substrates. These PANI(EB)–CSA ( = 0.5, 0.4, 0.3 mol) polymer films were developed through controlled temperature atmosphere 60 ± 2°C for 60 min, and with the help of temperature dependence of resistivity (ρ) values, high temperature coefficient of resistance (TCR) i.e. values, and figure of merit (ρ ) values of these films, thermal sensitivity were compared from that we observed. Among the three doping ratios the PANI(EB)–CSA$_{0.3 mol}$ film (4.4 m thick) on glass substrate resistivity (ρ) values in the range of 838–1699 .m with high TCR i.e. = 10,291 ppm/°C and figure of merit (ρ ) value in range of 8.62–17.48 m/°C seems to be the best. This paper deals with these superior thermal-sensing properties together with optical studies and surface topography by atomic force microscopy (AFM). These polymer films offer design advantages in developing ‘thin film polymer thermal sensor’.

  20. Fabrication of Robust Biomolecular Patterns by Reactive Microcontact Printing on N-Hydroxysuccinimide Ester-Containing Polymer Films

    NARCIS (Netherlands)

    Feng, Chuan Liang; Vancso, G. Julius; Schönherr, Holger

    2006-01-01

    The fabrication of robust biomolecule microarrays by reactive microcontact printing (CP) on spin-coated thin films of poly(N-hydroxysuccinimidyl methacrylate) (PNHSMA) on oxidized silicon and glass is described. The approach combines the advantages of activated polymer thin films as coupling layers,

  1. Effect of plasma fluorination variables on the deposition and growth of partially fluorinated polymer over PMMA films

    Directory of Open Access Journals (Sweden)

    Giovana da Silva Padilha

    2013-01-01

    Full Text Available In this work, an investigation was made of the modification of film surface of Poly(methylmethacrylate (PMMA using the plasma polymerization technique. PMMA films 10 µm thick were obtained by Spin-Coating starting from a chloroform solution (15.36% w/w. The films were exposed to the plasma of CHF3 at different gas pressures and exposure times to increase the thickness of fluorinated polymers onto PMMA films. The plasma fluorinated optical films were characterized by gravimetry, FTIR-ATR, contact angle of wetting, SEM and AFM. The surface fluorination of PMMA films can be inferred by the increase in contact angle under all experimental conditions, and confirmed with FTIR-ATR analysis. Gravimetry showed an increase of the fluorinated polymer layer over PMMA films, being 1.55 µm thick at 0.7 torr and 40 minutes of plasma exposure. The SEM analysis showed a well-defined layer of fluorinated polymer, with fluorine being detected in the EDS analysis. The film roughness for the fluorinated polymers was around of 200 Å, quite satisfactory for a 1.55 µm cladding.

  2. Effect of crystalline microstructure on the photophysical performance of polymer/perylene composite films

    Institute of Scientific and Technical Information of China (English)

    封伟; 徐友龙; 易文辉; 周峰; 王晓工; 吉野勝美

    2003-01-01

    To obtain high carrier mobility, better charge injection capability, and high photovoltaic device conversion efficiency, a powerful strategy is to improve the morphology of the polymer/dye composite films. Conjugated conducting polymer (CP) thin films doped with perylene derivative (PV) of various concentrations were prepared by spin-casting method, and their morphology and photovoltaic characteristics were examined. The change in morphology and molecular reorientation occurring in CP-PV composite films upon annealing at different temperatures was investigated using scanning electron microscopy, x-ray diffraction, Fourier transform infrared and UV-vis absorption. By changing the annealing temperature, PV microcrystallines of 8-10μm in size lying parallel to the substrate surface can be obtained.Annealing effect improved the photovoltaic performance of ITO/CP-PV/A1 Schottky-type solar cells, which can be attributed to the formation of an electron conducting PV crystal network. Preliminary studies indicate that the morphological structure in CP-PV composite films has an important influence to their photovoltaic properties.

  3. Mimicking conjugated polymer thin-film photophysics with a well-defined triblock copolymer in solution.

    Science.gov (United States)

    Brazard, Johanna; Ono, Robert J; Bielawski, Christopher W; Barbara, Paul F; Vanden Bout, David A

    2013-04-25

    Conjugated polymers (CPs) are promising materials for use in electronic applications, such as low-cost, easily processed organic photovoltaic (OPV) devices. Improving OPV efficiencies is hindered by a lack of a fundamental understanding of the photophysics in CP-based thin films that is complicated by their heterogeneous nanoscale morphologies. Here, we report on a poly(3-hexylthiophene)-block-poly(tert-butyl acrylate)-block-poly(3-hexylthiophene) rod-coil-rod triblock copolymer. In good solvents, this polymer resembles solutions of P3HT; however, upon the addition of a poor solvent, the two P3HT chains within the triblock copolymer collapse, affording a material with electronic spectra identical to those of a thin film of P3HT. Using this new system as a model for thin films of P3HT, we can attribute the low fluorescence quantum yield of films to the presence of a charge-transfer state, providing fundamental insights into the condensed phase photophysics that will help to guide the development of the next generation of materials for OPVs.

  4. Ultrasonic spray coating polymer and small molecular organic film for organic light-emitting devices

    Science.gov (United States)

    Liu, Shihao; Zhang, Xiang; Zhang, Letian; Xie, Wenfa

    2016-11-01

    Ultrasonic spray coating process (USCP) with high material -utilization, low manufacture costs and compatibility to streamline production has been attractive in researches on photoelectric devices. However, surface tension exists in the solvent is still a huge obstacle to realize smooth organic film for organic light emitting devices (OLEDs) by USCP. Here, high quality polymer anode buffer layer and small molecular emitting layer are successfully realized through USCP by introducing extra-low surface tension diluent and surface tension control method. The introduction of low surface tension methyl alcohol is beneficial to the formation of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) films and brings obvious phase separation and improved conductivity to PEDOT:PSS film. Besides, a surface tension control method, in which new stable tension equilibrium is built at the border of wetting layer, is proposed to eliminate the effect of surface tension during the solvent evaporation stage of ultrasonic spray coating the film consists of 9,9-Spirobifluoren-2-yl-diphenyl-phosphine oxide doped with 10 wt% tris [2-(p -tolyl) pyridine] iridium (III). A smooth and homogenous small molecular emitting layer without wrinkles is successfully realized. The effectiveness of the ultrasonic spray coating polymer anode buffer layer and small molecular emitting layer are also proved by introducing them in OLEDs.

  5. Sub-Rouse modes in polymer thin films: Coupling to density and responding to physical aging

    Science.gov (United States)

    Ngai, K. L.; Capaccioli, S.; Prevosto, D.

    2016-05-01

    The presence of sub-Rouse modes in bulk polymers with length scale and relaxation times in between the segmental α-relaxation and the Rouse modes had long been justified by theoretical consideration, and found in many experimental studies. The sub-Rouse modes had been seen directly in creep compliance measurements of polymer thin films by McKenna and co-workers. On decreasing film thickness, the sub-Rouse modes shift to shorter times like the segmental α-relaxation, but the shift of the former is less than the latter. We had used the sub-Rouse modes and the segmental mode to explain the two transitions found by ellipsometry in freestanding high molecular weight PS films by Pye and Roth (PR). The upper transition at a higher temperature originates from the sub-Rouse modes, and the lower transition comes from the segmental α-relaxation. On the other hand, PR suggested that the upper and the lower transitions both came from the segmental α-relaxation, and the upper transition occurs in ~90% of the material. In this paper we use dielectric relaxation data of freestanding films to rule out their suggestion. Furthermore, we demonstrate by experimental evidences that the sub-Rouse modes are coupled to density, and respond to physical aging to validate our interpretation.

  6. Polymer Thin Films and Interfaces; a Layer-by-Layer Approach

    Science.gov (United States)

    White, Ronald; Lipson, Jane

    2013-03-01

    In this talk we discuss new ways to model polymer films and interfaces, including properties such as density and concentration gradients, interfacial tension, and surface enrichment. We build on recent work where we developed a very simple equation of state approach for polymer thin films, and successfully applied it to determine thermodynamic properties and even to make predictions for the thickness-dependent depression of the thin film glass transition temperature. In that very simplified mean field model, the film properties across the entire interface region were treated as a ``whole sample'' average. Here, we take the next step, and develop a layer-by-layer equation of state model wherein details of the interface region are captured by allowing properties to vary from one discretized layer (within which properties are uniform) to the next. The model can be solved by imposing hydrostatic equilibrium in each layer, which then leads to predictions for the corresponding density gradient and other key interface properties. Work supported by the National Science Foundation.

  7. Ultrasonic spray coating polymer and small molecular organic film for organic light-emitting devices.

    Science.gov (United States)

    Liu, Shihao; Zhang, Xiang; Zhang, Letian; Xie, Wenfa

    2016-11-22

    Ultrasonic spray coating process (USCP) with high material -utilization, low manufacture costs and compatibility to streamline production has been attractive in researches on photoelectric devices. However, surface tension exists in the solvent is still a huge obstacle to realize smooth organic film for organic light emitting devices (OLEDs) by USCP. Here, high quality polymer anode buffer layer and small molecular emitting layer are successfully realized through USCP by introducing extra-low surface tension diluent and surface tension control method. The introduction of low surface tension methyl alcohol is beneficial to the formation of poly (3,4-ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS) films and brings obvious phase separation and improved conductivity to PEDOT:PSS film. Besides, a surface tension control method, in which new stable tension equilibrium is built at the border of wetting layer, is proposed to eliminate the effect of surface tension during the solvent evaporation stage of ultrasonic spray coating the film consists of 9,9-Spirobifluoren-2-yl-diphenyl-phosphine oxide doped with 10 wt% tris [2-(p -tolyl) pyridine] iridium (III). A smooth and homogenous small molecular emitting layer without wrinkles is successfully realized. The effectiveness of the ultrasonic spray coating polymer anode buffer layer and small molecular emitting layer are also proved by introducing them in OLEDs.

  8. High temperature behaviour of thermoelectric power of implanted polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Moreau, C.; Ratier, B.; Moliton, A.; Francois, B. [LEPOFI, Faculte des Sciences, Limoges (France)]|[Institut Charles Sadron, Strasbourg (France)

    1995-12-31

    The results of thermopower S measurements performed on implanted polyparaphenylene and polyimide films between 150 K and 450 K are presented. The implantations of Caesium or Iodine ions in polyparaphenylene with low parameters induce a sign of S characteristic to chemical nature of the implanted ions and an increase of lSl at around 350 K due to a transition from a VRH process to a polaronic conduction. With Iodine implanted sample at higher energy (E = 250 keV) and low dose (D = 2 x 10{sup 15} ions/cm{sup 2}) a transition from p type to n type doping at 400 K is attributed to a migration of negative oxygen ions as in the case of polyimide samples implanted with Caesium and Iodine ions where a similar behaviour of S is found. (Author).

  9. Dynamic Mechanical Properties of Bio-Polymer Graphite Thin Films

    Science.gov (United States)

    Saddam Kamarudin, M.; Rus, Anika Zafiah M.; Munirah Abdullah, Nur; Abdullah, M. F. L.

    2017-08-01

    Waste cooking oil is used as the main substances in producing graphite biopolymer thin films. Biopolymer is produce from the reaction of bio-monomer and cross linker with the ratio of 2:1 and addition of graphite with an increment of 2% through a slip casting method. The morphological surface properties of the samples are observed by using Scanning Electron Microscope (SEM). It is shown that the graphite particle is well mixed and homogenously dispersed in biopolymer matrix. Meanwhile, the mechanical response of materials by monitoring the change in the material properties in terms of frequency and temperature of the samples were determined using Dynamic Mechanical Analysis (DMA). The calculated cross-linked density of biopolymer composites revealed the increment of graphite particle loading at 8% gives highest results with 260.012 x 103 M/m3.

  10. Ion Transport and Discharge Characteristics of Polymer Blend (PVP/PVA) Electrolyte Films Doped with Potassium Iodide

    Science.gov (United States)

    Umadevi, C.; Mohan, K. R.; Achari, V. B. S.; Sharma, A. K.; Rao, V. V. R. N.

    2010-12-01

    Solid polymer blend electrolyte films based on PVP/PVA complexed with KI were prepared by the solution cast technique. Various experimental techniques such as electrical conductivity and transport number measurement were used to characterize the polymer electrolyte films. Electrochemical cells with the polymer electrolytes (PVP+PVA+KI) were fabricated in the configuration K/(PVP+PVA+KI)/ (I2+C+electrode). The discharge characteristics of the cells were studied under a constant load of 100 KΩ. The open-circuit voltage, short-circuit current and discharge time for the plateau region are measured. Several other cell parameters were evaluated and are reported.

  11. Electrical four-point probing of spherical metallic thin films coated onto micron sized polymer particles

    Energy Technology Data Exchange (ETDEWEB)

    Pettersen, Sigurd R., E-mail: sigurd.r.pettersen@ntnu.no, E-mail: jianying.he@ntnu.no; Stokkeland, August Emil; Zhang, Zhiliang; He, Jianying, E-mail: sigurd.r.pettersen@ntnu.no, E-mail: jianying.he@ntnu.no [NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Kristiansen, Helge [NTNU Nanomechanical Lab, Department of Structural Engineering, Norwegian University of Science and Technology (NTNU), NO-7491 Trondheim (Norway); Conpart AS, Dragonveien 54, NO-2013 Skjetten (Norway); Njagi, John; Goia, Dan V. [Center for Advanced Materials Processing, Clarkson University, Potsdam, New York 13699-5814 (United States); Redford, Keith [Conpart AS, Dragonveien 54, NO-2013 Skjetten (Norway)

    2016-07-25

    Micron-sized metal-coated polymer spheres are frequently used as filler particles in conductive composites for electronic interconnects. However, the intrinsic electrical resistivity of the spherical thin films has not been attainable due to deficiency in methods that eliminate the effect of contact resistance. In this work, a four-point probing method using vacuum compatible piezo-actuated micro robots was developed to directly investigate the electric properties of individual silver-coated spheres under real-time observation in a scanning electron microscope. Poly(methyl methacrylate) spheres with a diameter of 30 μm and four different film thicknesses (270 nm, 150 nm, 100 nm, and 60 nm) were investigated. By multiplying the experimental results with geometrical correction factors obtained using finite element models, the resistivities of the thin films were estimated for the four thicknesses. These were higher than the resistivity of bulk silver.

  12. Fullerenes as adhesive layers for mechanical peeling of metallic, molecular and polymer thin films.

    Science.gov (United States)

    Wieland, Maria B; Slater, Anna G; Mangham, Barry; Champness, Neil R; Beton, Peter H

    2014-01-01

    We show that thin films of C60 with a thickness ranging from 10 to 100 nm can promote adhesion between a Au thin film deposited on mica and a solution-deposited layer of the elastomer polymethyldisolaxane (PDMS). This molecular adhesion facilitates the removal of the gold film from the mica support by peeling and provides a new approach to template stripping which avoids the use of conventional adhesive layers. The fullerene adhesion layers may also be used to remove organic monolayers and thin films as well as two-dimensional polymers which are pre-formed on the gold surface and have monolayer thickness. Following the removal from the mica support the monolayers may be isolated and transferred to a dielectric surface by etching of the gold thin film, mechanical transfer and removal of the fullerene layer by annealing/dissolution. The use of this molecular adhesive layer provides a new route to transfer polymeric films from metal substrates to other surfaces as we demonstrate for an assembly of covalently-coupled porphyrins.

  13. Improvement of hemocompatibility of polycaprolactone film surfaces with zwitterionic polymer brushes.

    Science.gov (United States)

    Jiang, H; Wang, X B; Li, C Y; Li, J S; Xu, F J; Mao, C; Yang, W T; Shen, J

    2011-09-20

    Polycaprolactone (PCL) has been widely adopted as a scaffold biomaterial, but further improvement of the hemocompatibility of a PCL film surface is still needed for wide biomedical applications. In this work, the PCL film surface was functionalized with zwitterionic poly(3-dimethyl(methacryloyloxyethyl) ammonium propane sulfonate) (P(DMAPS)) brushes via surface-initiated atom transfer radical polymerization (ATRP) for enhancing hemocompatibility. Kinetics study revealed an approximately linear increase in graft yield of the functional P(DMAPS) brushes with polymerization time. The blood compatibilities of the modified PCL film surfaces were studied by platelet adhesion tests of platelet-rich plasma and human whole blood, hemolysis assay, and plasma recalcification time (PRT) assay. The improvement of hemocompatibility is dependent on the coverage of the grafted P(DMAPS) brushes on the PCL film. Lower or no platelet and blood cell adhesion was observed on the P(DMAPS)-grafted film surfaces. The P(DMAPS) grafting can further decrease hemolysis and enhance the PRT of the PCL surface. With the versatility of surface-initiated ATRP and the excellent hemocompatibility of zwitterionic polymer brushes, PCL films with desirable blood properties can be readily tailored to cater to various biomedical applications.

  14. NOVEL POLYMER WIDE VIEWING ANGLE COMPENSATION FILMS FOR LIQUID CRYSTAL DISPLAYS (LCDS)

    Institute of Scientific and Technical Information of China (English)

    Jason J.Ge; Bruce F.Li; Frank W.Harris; Stephen Z.D.Cheng

    2003-01-01

    We report on generating uniaxial negative birefringent compensation films, made of specifically designed polyimides. These polymers were synthesized via a polycondensation of dianhydride [such as 2,2′-bis(3,4-dicarboxyphenyl)hexafluoropropane dianhydride] and 2,2′-bis(trifiuoromethyl)-4,4′-diaminobiphenyl. The uniaxial negative birefiingent (nx =ny > nz) polyimide substrates are achieved using a solution-casting method in conventional solvents, which exhibit the desirable optical phase retardation [(nx - nz) x d] values from 50 to 400 nm varying with the film thickness. In these polyimide films, the long chain rigid molecules adopt intrinsic planar orientation. In detail, the majority of phenylene-imide rings and phenylenes preferentially adopt nearly planar conformations parallel to the film substrate. In addition, these films also possess high transparency (or transmittance) and little color shift. The unique color dispersion curve indicates that this type of materials is very suitable for the applications in LCDs due to an excellent mimic for the retardation color dispersion curve with respect to LC molecules. Significantly low in-plane retardation (< 1 nm) allows this new technology based film to achieve sufficiently high contrast ratio while highly negative retardation dramatically suppresses the gray scale inversion to improve the viewing angle performance in a variety of new mode LCDs.

  15. Relative humidity sensing using dye-doped polymer thin-films on metal substrates

    Science.gov (United States)

    Kumari, Madhuri; Ding, Boyang; Blaikie, Richard

    2015-12-01

    We demonstrate humidity sensors based on optical resonances sustained in sub-wavelength thick dye-doped polymer coatings on reflecting surfaces. As a result of coupling between dye molecular absorption and Fabry-Perot resonances in the air-coating-surface cavity, the absorption spectra of such thin-film structures show a strong resonant peak under certain illumination conditions. These resonances are sensitive to the structural and material properties of the thin-film, metal underlayer and ambient conditions and hence can be used for gas and vapor sensing applications. Specifically, we present our proof of principle experimental results for humidity sensing using a thin-film structure comprising Rhodamine6G-doped polyvinyl alcohol (PVA) films on silver substrates. Depending on the PVA film thickness, dye-concertation and angle of incidence, the resonant absorption peak can undergo either red-shift or blue-shift as RH level increases in the range 20% to 60%. Also, the absorption magnitude at certain wavelengths near to resonance show almost linear reduction which can be used as the sensing signal. Our simulation studies show a very good agreement with the experimental data. The spectral and temporal sensitivity of this thin-film structure is attributed to the changes in the thickness of the PVA layer which swells by absorbing water molecules

  16. Kinetic Effects on Self-Assembly and Function of Protein-Polymer Bioconjugates in Thin Films Prepared by Flow Coating

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Dongsook [Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave Cambridge MA 02142 USA; Huang, Aaron [Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave Cambridge MA 02142 USA; Olsen, Bradley D. [Department of Chemical Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave Cambridge MA 02142 USA

    2016-11-04

    The self-assembly of nanostructured globular protein arrays in thin films is demonstrated using protein–polymer block copolymers based on a model protein mCherry and the polymer poly(oligoethylene glycol acrylate) (POEGA). Conjugates are flow coated into thin films on a poly(ethylene oxide) grafted Si surface, forming self-assembled cylindrical nanostructures with POEGA domains selectively segregating to the air–film interface. Long-range order and preferential arrangement of parallel cylinders templated by selective surfaces are demonstrated by controlling relative humidity. Long-range order increases with coating speed when the film thicknesses are kept constant, due to reduced nucleation per unit area of drying film. Fluorescence emission spectra of mCherry in films prepared at <25% relative humidity shows a small shift suggesting that proteins are more perturbed at low humidity than high humidity or the solution state.

  17. Corrosion resistance and durability of siloxane ceramic/polymer films for aluminum alloys in marine environments

    Science.gov (United States)

    Kusada, Kentaro

    The objective of this study is to evaluate corrosion resistance and durability of siloxane ceramic/polymer films for aluminum alloys in marine environments. Al5052-H3 and Al6061-T6 were selected as substrates, and HCLCoat11 and HCLCoat13 developed in the Hawaii Corrosion Laboratory were selected for the siloxane ceramic/polymer coatings. The HCLCoat11 is a quasi-ceramic coating that has little to no hydrocarbons in its structure. The HCLCoat13 is formulated to incorporate more hydrocarbons to improve adhesion to substrate surfaces with less active functionalities. In this study, two major corrosion evaluation methods were used, which were the polarization test and the immersion test. The polarization tests provided theoretical corrosion rates (mg/dm 2/day) of bare, HCLCoat11-coated, and HCLCoat13-coated aluminum alloys in aerated 3.15wt% sodium chloride solution. From these results, the HCLCoat13-coated Al5052-H3 was found to have the lowest corrosion rate which was 0.073mdd. The next lowest corrosion rate was 0.166mdd of the HCLCoat11-coated Al5052-H3. Corrosion initiation was found to occur at preexisting breaches (pores) in the films by optical microscopy and SEM analysis. The HCLCoat11 film had many preexisting breaches of 1-2microm in diameter, while the HCLCoat13 film had much fewer preexisting breaches of less than 1microm in diameter. However, the immersion tests showed that the seawater immersion made HCLCoat13 film break away while the HCLCoat11 film did not apparently degrade, indicating that the HCLCoat11 film is more durable against seawater than the HCLCoat13. Raman spectroscopy revealed that there was some degradation of HCLCoat11 and HCLCoat13. For the HCLCoat11 film, the structure relaxation of Si-O-Si linkages was observed. On the other hand, seawater generated C-H-S bonds in the HCLCoat13 film resulting in the degradation of the film. In addition, it was found that the HCLCoat11 coating had anti-fouling properties due to its high water contact

  18. Preparation and characterization of grafted polyethylene based azo-polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Pilar Carreon-Castro, Maria del, E-mail: pilar@nucleares.unam.m [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Circuito Exterior Ciudad Universitaria C.P. 04510, Mexico D.F. (Mexico); Rivera, Ernesto [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior Ciudad Universitaria C.P. 04510, Mexico D.F. (Mexico); Jesus Cruz, Jose de; Zavaleta, Gerardo [Instituto de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Circuito Exterior Ciudad Universitaria C.P. 04510, Mexico D.F. (Mexico); Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior Ciudad Universitaria C.P. 04510, Mexico D.F. (Mexico); Gutierrez-Nava, Manuel [Instituto de Investigaciones en Materiales, Universidad Nacional Autonoma de Mexico, Circuito Exterior Ciudad Universitaria C.P. 04510, Mexico D.F. (Mexico)

    2010-05-31

    A series of grafted azo-polymers was prepared from commercial low density polyethylene thin plates (PE). Polyethylene was reacted in the presence of acryloyl chloride using gamma irradiation to give precursor grafted polymers. These materials were esterified in the presence of six different commercial azo-dyes: (E)-2-(ethyl(4-((4-nitrophenyl)diazenyl)phenyl)amino)ethanol (Disperse Red-1, DR-1), (E)-2-((4-((2-chloro-4-nitrophenyl)diazenyl)phenyl)(ethyl)amino)ethanol (Disperse Red-13, DR-13), (E)-2,2'-(4-((4-nitrophenyl)diazenyl)phenylazanediyl)diethanol (Disperse Red-19, DR-19), (E)-4-((4-nitrophenyl)diazenyl)aniline (Disperse Orange-3, DO-3), 4-((E)-(4-((E)-phenyldiazenyl)naphthalen-1-yl)diazenyl)phenol (Disperse Orange-13, DO-13) and 2-methyl-4-((E)-(4-((E)-phenyldiazenyl)phenyl)diazenyl)phenol (Disperse Yellow-7, DY-7) to give the expected grafted azo-polymer films. The obtained polymers were fully characterized; their thermal, optical properties and morphology were studied. In particular, the influence of the irradiation conditions and the incorporated azo-dye on the polymer properties is discussed.

  19. OPTICAL PHASE CONJUGATION RESPONSE OF PHOTOINDUCED POLYMER FILMS CONTAINING AZOBENZENE MOIETIES WITH CHIRAL GROUP

    Institute of Scientific and Technical Information of China (English)

    Ze-da Xu; Yong Zhang; Xing-he Fan; Xin-hua Wan; Qi-feng Zhou

    2002-01-01

    An optically active monomer containing azobenzene moieties with chiral group (s-2-methyl-butyl), 4-[2-(methacryloyloxy)ethyloxy]-4'-(s-2-methyl-1-butyloxycarbonyl) azobenzene (M1) was synthesized. Polymer (PM1) possessing optical phase conjugated response was obtained by homopolymerization of the optically active monomer (M1) using free radical polymerization. The polymer was very soluble in common solvents and good optical quality films could be easily fabricated by spin coating. The optical phase conjugated responses of the polymer PM1 were measured by degenerate four-wave mixing (DFWM). In comparison with polymer containing no chiral group, it was found from the preliminary measurement of photoisomeric change that optical phase conjugated response of the PM1 in the long-range order hexagonal symmetry microstructure could be easily controlled by choosing the appropriate polarization direction of the irradiating beams (514.5 nm) and the irradiating number, presumably due to the chiral group in the PM1 molecular structure. For the case of the polymer investigated here, a chiral group side chain was introduced to increase optical phase conjugated response intensity with different polarization directions of the irradiating beams, which aims originally at searching for a new photoactive material.

  20. Refractive indices of polymer-dispersed liquid-crystal film materials: Epoxy-based systems

    Science.gov (United States)

    Vaz, Nuno A.; Montgomery, G. Paul, Jr.

    1987-10-01

    Polymer-dispersed liquid crystal (PDLC) films are potentially useful in applications requiring electrically controllable light transmission. In these applications, both a high on-state transmittance and a strong off-state attenuation are often needed over a wide operating temperature range. These transmittance characteristics depend strongly on the refractive indices of the materials in the PDLC films. We have measured the temperature dependent refractive indices of typical PDLC film materials and the temperature dependent electro-optic transmittance of a PDLC film composed of liquid crystal microdroplets dispersed in an epoxy matrix. We show that our refractive index measurements can account for all the features in the measured transmittance characteristics and discuss several methods for controlling refractive indices to optimize electro-optic transmittance over an extended temperature range. We have also measured the room temperature refractive indices of mixtures of epoxy resins and hardeners as a function of composition. We discuss the problems associated with predicting the refractive indices of such mixtures in terms of either the volume fractions or mole fractions of the mixture components. These considerations are important in matching refractive indices of droplets and matrix materials to maximize on-state transmittance. The refractive indices of epoxy matrix materials increase monotonically with time during their chemical cure. The measured time dependence can be described by a simple model in which the concentrations of the reacting resin and hardener each decay exponentially in time with their own characteristic time constants while the concentration of the cured polymer increases. Finally, we relate the measured rates of index change with temperature to the coefficients of volume expansion of PDLC film materials; the results are used to discuss the mechanical stability of PDLC films.

  1. Mucoadhesive polymer films for tissue retraction in laparoscopic surgery: Ex-vivo study on their mechanical properties.

    Science.gov (United States)

    Wang, Zhigang; Tai, Lik-Ren; McLean, Donald; Wright, Emma J; Florence, Gordon J; Brown, Stuart I; Andre, Pascal; Cuschieri, Alfred

    2014-01-01

    Safe and effective manipulation of soft tissue during laparoscopic procedures can be achieved by the use of mucoadhesive polymer films. A series of novel adhesive polymer films were formulated in house based on either Carbopol or Chitosan modified systems. The mechanical properties of the polymers and their adherence to bowel were evaluated using ex-vivo pig bowel immersed in 37°C water bath and connected to an Instron tensiometer. Young's modulus was 300 kPa for the Carbopol-polymer and 5 kPa for the Chitosan-polymer. The Chitosan-polymer exhibited much larger shear adhesion than its tensile adhesion: 3.4 N vs. 1.2. Both tensile and shear adhesions contributed to the large retraction force (2.6 N) obtained during l polymer-bowel retraction testing. Work of adhesion at the polymer/serosa interface, defined as the area under the force curve, was 64 mJ, which is appreciably larger than that reported with existing polymers. In conclusion, adhesive polymers can stick to the serosal side of the bowel with an adhesive force, which is sufficient to lift the bowel, providing a lower retraction stress than that caused by laparoscopic grasping which induces high localized pressures on the tissue.

  2. Generation of Hierarchically Ordered Structures on a Polymer Film by Electrohydrodynamic Structure Formation.

    Science.gov (United States)

    Tian, Hongmiao; Shao, Jinyou; Hu, Hong; Wang, Li; Ding, Yucheng

    2016-06-29

    The extensive applications of hierarchical structures in optoelectronics, micro/nanofluidics, energy conservation, etc., have led to the development of a variety of approaches for their fabrication, which can be categorized as bottom-up or top-down strategies. Current bottom-up and top-down strategies bear a complementary relationship to each other due to their processing characteristics, i.e., the advantages of one method correspond to the disadvantages of the other, and vice versa. Here we propose a novel method based on electrohydrodynamic structure formation, aimed at combining the main advantages of the two strategies. The method allows the fabrication of a hierarchically ordered structure with well-defined geometry and high mechanical durability on a polymer film, through a simple and low-cost process also suitable for mass-production. In this approach, upon application of an electric field between a template and a substrate sandwiching an air gap and a polymer film, the polymer is pulled toward the template and further flows into the template cavities, resulting in a hierarchical structure with primary and secondary patterns determined by electrohydrodynamic instability and by the template features, respectively. In this work, the fabrication of a hierarchical structure by electrohydrodynamic structure formation is studied using numerical simulations and experimental tests. The proposed method is then employed for the one-step fabrication of a hierarchical structure exhibiting a gradual transition in the periodicity of the primary structure using a slant template and a flat polymer film, which presents an excellent performance on controllable wettability.

  3. Superhydrophobic polymer films via aerosol assisted deposition - Taking a leaf out of nature's book

    Energy Technology Data Exchange (ETDEWEB)

    Crick, Colin R. [Materials Chemistry Research Centre, Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ (United Kingdom); Parkin, Ivan P., E-mail: i.p.parkin@ucl.ac.u [Materials Chemistry Research Centre, Department of Chemistry, University College London, 20 Gordon Street, London WC1H OAJ (United Kingdom)

    2010-05-31

    Aerosol assisted deposition of three sets of polymer films based on commercially available resins was achieved on various substrates. The films were characterised using a range of methods, including water contact and slip angle to determine water repellent properties. The aerosol assisted deposition inside the chemical vapour deposition reactor was unique in generating a highly rough superhydrophobic surface with water contact angles up to 170{sup o}. During the deposition process, two of the polymers were cured resulting in the development of high surface morphology. It was observed that the polymer that did not cure did not develop such a rough surface resulting in a lower water contact angle ({approx} 99{sup o}). The superhydrophobic films had a Cassie-Baxter type wetting with water failing to penetrate the surface porosity, water spraying on the surface would bounce off. These films had exceptionally low slide angles of ca 1-2{sup o} from the horizontal.

  4. Development of Zingiber officinale in oral dissolving films: Effect of polymers on in vitro, in vivo parameters and clinical efficacy

    Directory of Open Access Journals (Sweden)

    Anwar S Daud

    2011-01-01

    Full Text Available Oral dissolving drug delivery system offers a solution for those patients having difficulty in swallowing tablets/capsules, etc. Zingiber officinale, has been used for medicinal purpose since antiquity to treat motion sickness, pregnancy, and cancer-chemotherapy-induced vomiting, mild stomach upset, cough, chronic bronchial problems, and low-grade infections of all kinds and anorexia condition. This work investigates the possibility of developing Zingiber officinale oral dissolving films allowing fast, reproducible dissolution in oral cavity; thus bypassing first pass metabolism. The oral dissolving films were prepared by solvent-casting method. Prepared films were evaluated for film-forming properties, physico-mechanical properties, palatability, microbial limit test, accelerated stability studies, and clinical efficacy test. The different polymers such as hydroxypropyl methylcellulose 5cps, maltodextrin, pullulan, and polyvinyl alcohol were explored individually and in combination with each other for the formation of film. Among all polymers, maltodextrin and HPMC 5 cps alone and in combination showed excellent film-forming properties as well as very good physico-mechanical properties. The films resulted into excellent palatability along with least disintegrating time. But at accelerated stability studies, only HPMC 5 cps was found to be stable when compared with other formulations. So, it was concluded that HPMC 5 cps is the best film forming as well as stable polymer with respect to Zingiber officinale oral dissolving film.

  5. Influence of structure 3,5,7,3‧,4‧-Pentahydroxyflavone-based polymer films on their optical transparency

    Science.gov (United States)

    Mishurov, Dmytro; Voronkin, Andrii; Roshal, Alexander; Bogatyrenko, Sergey

    2017-02-01

    Optical properties and morphology of polymer films based on diglycidyl ether of bis-phenol A and on natural compound 3,5,7,3‧,4‧-pentahydroxyflavone (quercetin) using UV-vis spectroscopy, scanning electron microscopy and powder X-ray diffraction methods have been investigated. The influence of ordering degree of the polymers, flexibility of their chains, intensity of intermolecular interaction between the quercetine moieties on the polymers' morphology was discussed. It is shown that all the quercetine-based polymer films are transparent at visible and near infrared regions beginning from 420 to 450 nm. Low optical transparency in the short-wavelength region can be explained the self-absorption of quercetin moieties in the polymer chains.

  6. Water-Resistant and Transparent Plastic Films from Functionalizable Organic Polymers: Coordination Polymers as Templates for Solid-State [2+2]-Photopolymerization.

    Science.gov (United States)

    Garai, Mousumi; Biradha, Kumar

    2017-01-05

    An organic polymer containing cyclobutanes and amides as backbones and pyridyl groups as sidearms was synthesized by single-crystal-to-single-crystal (SCSC) [2+2]-photopolymerization in the coordination polymers (CPs) of diene. The diene molecule was photo-inactive in its crystals and formed a triply intertwined 1D-helical CP with Cd(NO3 )2 and Cu(NO3 )2 salts. The 1D-CP was transformed into a coordination polymer of organic polymers containing threefold interpenetrated 3D-networks of CdSO4 topology through a [2+2]-reaction in SCSC manner upon irradiation. The organic polymer was separated from its CPs and found to have an unusually high degree of polymerization for this type of reaction. Furthermore, the organic polymer was amenable for N-alkylation reactions such as methylation, propylation, and decylation. The formate salts of the organic polymer and the methylated polymer were shown to form plastic films with a combination of properties such as high transparency, tensile strengths, gas permeability, thermal stability, water-resistance, and resistance to other organic solvents. The methylated polymer was also able to capture chromate ions and anionic dyes from aqueous solutions.

  7. Thin film thermistor with positive temperature coefficient of resistance based on phase separated blends of ferroelectric and semiconducting polymers

    Science.gov (United States)

    Lenz, Thomas; Sharifi Dehsari, Hamed; Asadi, Kamal; Blom, Paul W. M.; Groen, Wilhelm A.; de Leeuw, Dago M.

    2016-09-01

    We demonstrate that ferroelectric memory diodes can be utilized as switching type positive temperature coefficient (PTC) thermistors. The diode consists of a phase separated blend of a ferroelectric and a semiconducting polymer stacked between two electrodes. The current through the semiconducting polymer depends on the ferroelectric polarization. At the Curie temperature the ferroelectric polymer depolarizes and consequently the current density through the semiconductor decreases by orders of magnitude. The diode therefore acts as switching type PTC thermistor. Unlike their inorganic counterparts, the PTC thermistors presented here are thin film devices. The switching temperature can be tuned by varying the Curie temperature of the ferroelectric polymer.

  8. Heavy ion irradiation effects of polymer film on absorption of light

    Energy Technology Data Exchange (ETDEWEB)

    Kasai, Noboru; Seguchi, Tadao [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Arakawa, Tetsuhito

    1997-03-01

    Ion irradiation effects on the absorption of light for three types of polymer films; polyethylene-terephthalate (PET), polyethylene-naphthalate (PEN), and polyether-ether-ketone (PEEK) were investigated by irradiation of heavy ions with Ni{sup 4+}(15MeV), O{sup 6+}(160MeV), and Ar{sup 8+}(175MeV), and compared with electron beams(EB) irradiation. The change of absorption at 400nm by a photometer was almost proportional to total dose for ions and EB. The absorption per absorbed dose was much high in Ni{sup 4+}, but rather small in O{sup 6+} and Ar{sup 8+} irradiation, and the absorption by EB irradiation was accelerated by the temperature of polymer film during irradiation. The beam heating of materials during ion irradiation was assumed, especially for Ni ion irradiation. The heavy ion irradiation effect of polymers was thought to be much affected by the ion beam heating than the linear energy transfer(LET) of radiation source. (author)

  9. Edge isolation of transparent conductive polymer (TCP) thin films on flexible substrates using UV laser ablation.

    Science.gov (United States)

    Hsiao, Wen-Tse; Tseng, Shih-Feng; Huang, Kuo-Cheng; Chiang, Donyau; Chen, Ming-Fei

    2012-06-01

    The purpose of this study was to directly use the writing techniques for the complex electrode edge isolation of transparent conductive polymer (TCP) thin films by a nanosecond pulsed UV laser processing system. The processing parameters including the laser pulse energy, the pulse repetition frequency, and the scan speed of galvanometers were examined to ablate the TCP films deposited on polyethylene terephtalate substrates of 188 microm thick. The thickness of TCP films was approximately 20 nm. The laser pulse repetition frequency and the scan speed of galvanometers were applied to calculate the overlapping rate of laser spots and to discuss the patterning region quality. Surface morphology, edge quality, and width and depth of edge isolated patterning structures after laser ablation process were measured by a three-dimensional confocal laser scanning microscope. In addition, the electrical conductivity of ablated TCP films was measured by a four-point probes instrument. After isolated line patterning was formed, the ablated TCP films with a better edge quality were obtained directly when the overlapping rate of laser spots, the scan speed, and the pulse repetition rate were 83.3%, 200 mm/s, and 40 kHz, respectively. The better surface morphology of electrode pattern structures was also obtained when the scan speed and the pulse repetition rate were 500 mm/s and 40 kHz, respectively.

  10. Effects of rf power on chemical composition and surface roughness of glow discharge polymer films

    Science.gov (United States)

    Zhang, Ling; He, Xiaoshan; Chen, Guo; Wang, Tao; Tang, Yongjian; He, Zhibing

    2016-03-01

    The glow discharge polymer (GDP) films for laser fusion targets were successfully fabricated by plasma enhanced chemical vapor deposition (PECVD) at different radio frequency (rf) powers. The films were deposited using trans-2-butene (T2B) mixed with hydrogen as gas sources. The composition and state of plasma were diagnosed by quadrupole mass spectrometer (QMS) and Langmuir probe during the deposition process. The composition, surface morphology and roughness were investigated by Fourier transform infrared spectroscopy (FTIR), scanning electron microscope (SEM) and white-light interferometer (WLI), respectively. Based on these observation and analyses, the growth mechanism of defects in GDP films were studied. The results show that, at low rf power, there is a larger probability for secondary polymerization and formation of multi-carbon C-H species in the plasma. In this case, the surface of GDP film turns to be cauliflower-like. With the increase of rf power, the degree of ionization is high, the relative concentration of smaller-mass hydrocarbon species increases, while the relative concentration of larger-mass hydrocarbon species decreases. At higher rf power, the energy of smaller-mass species are high and the etching effects are strong correspondingly. The GDP film's surface roughness shows a trend of decrease firstly and then increase with the increasing rf power. At rf power of 30 W, the surface root-mean-square roughness (Rq) drops to the lowest value of 12.8 nm, and no "void" defect was observed.

  11. Plasma polymers deposited in atmospheric pressure dielectric barrier discharges: Influence of process parameters on film properties

    Energy Technology Data Exchange (ETDEWEB)

    Fricke, Katja, E-mail: k.fricke@inp-greifswald.de [Leibniz Institute for Plasma Science and Technology e.V. (INP Greifswald), Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Girard-Lauriault, Pierre-Luc [Plasma Processing Laboratory, Department of Chemical Engineering, McGill University, 3610 rue University, Montreal, QC H3A 0C5 (Canada); Weltmann, Klaus-Dieter [Leibniz Institute for Plasma Science and Technology e.V. (INP Greifswald), Felix-Hausdorff-Str. 2, 17489 Greifswald (Germany); Wertheimer, Michael R. [Department of Engineering Physics, École Polytechnique de Montréal, Box 6079, Station Centre-Ville, Montreal, QC H3C 3A7 (Canada)

    2016-03-31

    We present results on the deposition of plasma polymer (PP) films in a dielectric barrier discharge system fed with mixtures of argon or nitrogen carrier gas plus different hydrocarbon precursors, where the latter possess different carbon-to-hydrogen ratios: CH{sub 4} < C{sub 2}H{sub 6} < C{sub 2}H{sub 4} = C{sub 3}H{sub 6} < C{sub 2}H{sub 2}. The influence of precursor gas mixture and flow rate, excitation frequency, and absorbed power on PP film compositions and properties has been investigated. The discharge was characterized by electrical measurements, while the chemical compositions and structures of coatings were analysed by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, total combustion, and elastic recoil detection analyses, the latter two for determining carbon-to-hydrogen ratios. Scanning electron microscopy was used to study the coatings' morphology, and profilometry for evaluating deposition rates. - Highlights: • Atmospheric pressure DBD is used to deposit organic hydrocarbon films. • High deposition rates can be achieved by varying the power and/or gas mixture ratio. • Process parameters affect the films' surface chemical composition and morphology. • Deposited films are not soluble in aqueous environment. • No delamination of coatings produced from argon plasma.

  12. Dual Imprinted Polymer Thin Films via Pattern Directed Self-Organization.

    Science.gov (United States)

    Grolman, Danielle; Bandyopadhyay, Diya; Al-Enizi, Abdullah; Elzatahry, Ahmed; Karim, Alamgir

    2017-06-21

    Synthetic topographically patterned films and coatings are typically contoured on one side, yet many of nature's surfaces have distinct textures on different surfaces of the same object. Common examples are the top and bottom sides of the butterfly wing or lotus leaf, onion shells, and the inside versus outside of the stem of a flower. Inspired by nature, we create dual (top and bottom) channel patterned polymer films. To this end, we first develop a novel fabrication method to create ceramic line channel relief structures by converting the oligomeric residue of stamped poly(dimethylsiloxane) (PDMS) nanopatterns on silicon substrates to glass (SiOx, silica) by ultraviolet-ozone (UVO) exposure. These silica patterned substrates are flow coated with polystyrene (PS) films and confined within an identically patterned top confining soft PDMS elastomer film. Annealing of the sandwich structures drives the PS to rapidly mold fill the top PDMS pattern in conjunction with a dewetting tendency of the PS on the silica pattern. Varying the film thickness h, from less than to greater than the pattern height, and varying the relative angle between the top-down and bottom-up patterned confinement surfaces create interesting uniform and nonuniform digitized defects in PS channel patterns, as also a defect-free channel regime. Our dual patterned polymer channels provide a novel fabrication route to topographically imprinted Moiré patterns (whose applications range from security encrypting holograms to sensitive strain gauges), and their basic laser light diffractions properties are illustrated and compared to graphical simulations and 2D-FFT of real-space AFM channel patterns. While traditional "geometrical" and "fringe" Moiré patterns function by superposition of two misaligned optical patterned transmittance gratings, our topographic pattern gratings are quite distinct and may allow for more unique holographic optical characteristics with further development.

  13. Analysis of polymer surfaces and thin-film coatings with Raman and surface enhanced Raman scattering

    CERN Document Server

    McAnally, G D

    2001-01-01

    This thesis investigates the potential of surface-enhanced Raman scattering (SERS) for the analysis and characterisation of polymer surfaces. The Raman and SERS spectra from a PET film are presented. The SERS spectra from the related polyester PBT and from the monomer DMT are identical to PET, showing that only the aromatic signals are enhanced. Evidence from other compounds is presented to show that loss of the carbonyl stretch (1725 cm sup - sup 1) from the spectra is due to a chemical interaction between the silver and surface carbonyl groups. The interaction of other polymer functional groups with silver is discussed. A comparison of Raman and SERS spectra collected from three faces of a single crystal shows the SERS spectra are depolarised. AFM images of the silver films used to obtain SERS are presented. They consist of regular islands of silver, fused together to form a complete film. The stability and reproducibility and of these surfaces is assessed. Band assignments for the SERS spectrum of PET are ...

  14. A simple two-step method to fabricate highly transparent ITO/polymer nanocomposite films

    Science.gov (United States)

    Liu, Haitao; Zeng, Xiaofei; Kong, Xiangrong; Bian, Shuguang; Chen, Jianfeng

    2012-09-01

    Transparent functional indium tin oxide (ITO)/polymer nanocomposite films were fabricated via a simple approach with two steps. Firstly, the functional monodisperse ITO nanoparticles were synthesized via a facile nonaqueous solvothermal method using bifunctional chemical agent (N-methyl-pyrrolidone, NMP) as the reaction solvent and surface modifier. Secondly, the ITO/acrylics polyurethane (PUA) nanocomposite films were fabricated by a simple sol-solution mixing method without any further surface modification step as often employed traditionally. Flower-like ITO nanoclusters with about 45 nm in diameter were mono-dispersed in ethyl acetate and each nanocluster was assembled by nearly spherical nanoparticles with primary size of 7-9 nm in diameter. The ITO nanoclusters exhibited an excellent dispersibility in polymer matrix of PUA, remaining their original size without any further agglomeration. When the loading content of ITO nanoclusters reached to 5 wt%, the transparent functional nanocomposite film featured a high transparency more than 85% in the visible light region (at 550 nm), meanwhile cutting off near-infrared radiation about 50% at 1500 nm and blocking UV ray about 45% at 350 nm. It could be potential for transparent functional coating materials applications.

  15. Rapid and selective detection of viruses using virus-imprinted polymer films.

    Science.gov (United States)

    Karthik, A; Margulis, K; Ren, K; Zare, R N; Leung, L W

    2015-12-01

    We prepared a nanopatterned polymer film of polydimethylsiloxane (PDMS) via virus imprinting. The imprinted surface exhibited nanoscale cavities with the mean size of 120 ± 4 nm. These cavities demonstrated the ability to preferentially capture a target virus from an aqueous suspension of ultralow volume (5 μL) after only 1 minute of contact. Two inactivated viruses with similar shape, Influenza A (HK68) and Newcastle Disease Virus (NDV), were employed as model pathogens. The polymer film, which was first imprinted with HK68 and exposed sequentially to suspensions containing fluorescently labeled NDV and HK68, was able to preferentially bind HK68 at a capture ratio of 1 : 8.0. When we reversed the procedure and imprinted with NDV, the capture ratio was 1 : 7.6. These results were obtained within 20 minutes of static exposure. The suspensions contained viruses at concentrations close to those occurring physiologically in influenza infections. The limit of detection was approximately 8 fM. Production of virus-imprinted films can be readily scaled to large quantities and yields a disposable, simple-to-use device that allows for rapid detection of viruses.

  16. Effect of chain end group on surface glass transition temperature of thin polymer film

    Science.gov (United States)

    Jiang, Xiqun; Yang, Chang Zheng; Tanaka, Keiji; Takahara, Atsushi; Kajiyama, Tisato

    2001-04-01

    Surface glass transition behaviors of proton end capped poly(2-vinylpyridine) (P2VP-H) and perfluoroalkyl end capped poly(2-vinylpyridine) (P2VP-C 2C 8F) thin films were investigated based on temperature-dependent lateral force microscopic (TDLFM) measurement. It is found that the species of chain end groups have significant influence on the surface glass transition temperature of the thin polymer film. For both samples, it is revealed that the surface glass transition temperatures decrease significantly in comparison to the bulk ones, and the magnitude order of reduction in surface Tg for P2VP-C 2C 8F is larger than that for P2VP-H. The apparent activation energy of surface α-relaxation calculated from the Arrhenius plot is ca. 292±40 and 212±40 kJ/mol for P2VP-H and P2VP-C 2C 8F, respectively, and is much smaller than the bulk one. The depression of the surface Tg for thin polymer films is explained by the excess free volume induced by the enrichment of chain end groups at the surface.

  17. Nanocomposite metal/plasma polymer films prepared by means of gas aggregation cluster source

    Energy Technology Data Exchange (ETDEWEB)

    Polonskyi, O.; Solar, P.; Kylian, O.; Drabik, M.; Artemenko, A.; Kousal, J.; Hanus, J.; Pesicka, J.; Matolinova, I. [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic); Kolibalova, E. [Tescan, Libusina trida 21, 632 00 Brno (Czech Republic); Slavinska, D. [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic); Biederman, H., E-mail: bieder@kmf.troja.mff.cuni.cz [Charles University in Prague, Faculty of Mathematics and Physics, V Holesovickach 2, 18000 Prague 8 (Czech Republic)

    2012-04-02

    Nanocomposite metal/plasma polymer films have been prepared by simultaneous plasma polymerization using a mixture of Ar/n-hexane and metal cluster beams. A simple compact cluster gas aggregation source is described and characterized with emphasis on the determination of the amount of charged clusters and their size distribution. It is shown that the fraction of neutral, positively and negatively charged nanoclusters leaving the gas aggregation source is largely influenced by used operational conditions. In addition, it is demonstrated that a large portion of Ag clusters is positively charged, especially when higher currents are used for their production. Deposition of nanocomposite Ag/C:H plasma polymer films is described in detail by means of cluster gas aggregation source. Basic characterization of the films is performed using transmission electron microscopy, ultraviolet-visible and Fourier-transform infrared spectroscopies. It is shown that the morphology, structure and optical properties of such prepared nanocomposites differ significantly from the ones fabricated by means of magnetron sputtering of Ag target in Ar/n-hexane mixture.

  18. Flexible thin-film battery based on solid-like ionic liquid-polymer electrolyte

    Science.gov (United States)

    Li, Qin; Ardebili, Haleh

    2016-01-01

    The development of high-performance flexible batteries is imperative for several contemporary applications including flexible electronics, wearable sensors and implantable medical devices. However, traditional organic liquid-based electrolytes are not ideal for flexible batteries due to their inherent safety and stability issues. In this study, a non-volatile, non-flammable and safe ionic liquid (IL)-based polymer electrolyte film with solid-like feature is fabricated and incorporated in a flexible lithium ion battery. The ionic liquid is 1-Ethyl-3-methylimidazolium dicyanamide (EMIMDCA) and the polymer is composed of poly(vinylidene fluoride-co-hexafluoropropene) (PVDF-HFP). The electrolyte exhibits good thermal stability (i.e. no weight loss up to 300 °C) and relatively high ionic conductivity (6 × 10-4 S cm-1). The flexible thin-film lithium ion battery based on solid-like electrolyte film is encapsulated using a thermal-lamination process and demonstrates excellent electrochemical performance, in both flat and bent configurations.

  19. Brush-Coated Nanoparticle Polymer Thin Films: structure-mechanical-optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Green, Peter F. [Univ. of Michigan, Ann Arbor, MI (United States). Dept. of Materials Science and Engineering

    2014-08-15

    Our work was devoted to understanding the structure and properties of a class of thin film polymer nanocomposites (PNCs). PNCs are composed of polymer hosts into which nanoparticles (metallic nanoparticles, quantum dots, nanorods, C60, nanotubes) are incorporated. PNCs exhibit a diverse range of functional properties (optical, electronic, mechanical, biomedical, structural), determined in part by the chemical composition of the polymer host and the type of nanoparticle. The properties PNCs rely not only on specific functional, size-dependent, behavior of the nanoparticles, but also on the dispersion, and organizational order in some cases, inter-nanoparticle separation distances, and on relative interactions between the nanoparticles and the host. Therefore the scientific challenges associated with understanding the interrelations between the structure and function/properties of PNCs are far more complex than may be understood based only on the knowledge of the compositions of the constituents. The challenges of understanding the structure-function behavior of PNCs are further compounded by the fact that control of the dispersion of the nanoparticles within the polymer hosts is difficult; one must learn how to disperse inorganic particles within an organic host. The goal of this proposal was to develop an understanding of the connection between the structure and the thermal (glass transition), mechanical and optical properties of a specific class of PNCs. Specifically PNCs composed of polymer chain grafted gold nanoparticles within polymer hosts. A major objective was to understand how to develop basic principles that enable the fabrication of functional materials possessing optimized morphologies and combinations of materials properties.

  20. Ultrafast All-Optical Phenomena and Devices Using Conjugated Polymer Thin Films

    Science.gov (United States)

    Hays, Andrew Wayne

    The Su-Schrieffer-Heeger formalism predicts shifts of oscillator strength from the valence and conduction bands to new sub-gap absorptions for both degenerate and nondegenerate ground state conjugated polymers. Photoinduced absorption studies on polyacetylene confirmed this behavior in degenerate ground state polymers. The shift in oscillator strength to form solitons takes place in less than one optical phonon period (family) with similar time scale for the creation of polarons and with time decays on the order of 10-1000 ps. These fast (and large) changes in the optical absorption spectrum suggest that the materials are excellent candidates for use in nonlinear optical devices and systems. Thin film waveguides are the obvious first choice. We have used the focused light attenuated total reflection technique (FLATR) to measure both the sign and the magnitude of the change in the complex index of refraction of a conjugated polymer in a waveguide configuration. In poly(3-hexylthiophene) we observe a picosecond decrease in the refractive index correlated with the subgap induced absorption. The magnitude of the picosecond modulation is | n_2 | ~eq 1 times 10^{ -4} (MW/cm^2)^{ -1}. Optical devices based on waveguiding are inherently serial devices. These sorts of devices would find use in general purpose digital optical computers and switching application for telecommunications. We have explored the possibility of using an engineered polymer in a parallel processing architecture. The final project in this thesis describes a femtosecond optical correlator based on degenerate four-wave mixing in the conjugated polymer poly (1,6 heptadiester) (PHDE). PHDE is a degenerate ground state polymer with a backbone similar to trans-polyacetylene. This material was synthesized to retain the ultrafast time response of polyacetylene and large optical nonlinearities. Additionally, side groups were added to yield solubility in organic solvents and improve environmental stability. Our

  1. Conformal organic-inorganic hybrid network polymer thin films by molecular layer deposition using trimethylaluminum and glycidol.

    Science.gov (United States)

    Gong, Bo; Peng, Qing; Parsons, Gregory N

    2011-05-19

    Growing interest in nanoscale organic-inorganic hybrid network polymer materials is driving exploration of new bulk and thin film synthesis reaction mechanisms. Molecular layer deposition (MLD) is a vapor-phase deposition process, based on atomic layer deposition (ALD) which proceeds by exposing a surface to an alternating sequence of two or more reactant species, where each surface half-reaction goes to completion before the next reactant exposure. This work describes film growth using trimethyl aluminum and heterobifunctional glycidol at moderate temperatures (90-150 °C), producing a relatively stable organic-inorganic network polymer of the form (-Al-O-(C(4)H(8))-O-)(n). Film growth rate and in situ reaction analysis indicate that film growth does not initially follow a steady-state rate, but increases rapidly during early film growth. The mechanism is consistent with subsurface species transport and trapping, previously documented during MLD and ALD on polymers. A water exposure step after the TMA produces a more linear growth rate, likely by blocking TMA subsurface diffusion. Uniform and conformal films are formed on complex nonplanar substrates. Upon postdeposition annealing, films transform into microporous metal oxides with ∼5 Å pore size and surface area as high as ∼327 m(2)/g, and the resulting structures duplicate the shape of the original substrate. These hybrid films and porous materials could find uses in several research fields including gas separations and diffusion barriers, biomedical scaffolds, high surface area coatings, and others.

  2. Observing phthalate leaching from plasticized polymer films at the molecular level.

    Science.gov (United States)

    Zhang, Xiaoxian; Chen, Zhan

    2014-05-06

    Phthalates, the most widely used plasticizers in poly(vinyl chloride) (PVC), have been extensively studied. In this paper, a highly sensitive, easy, and effective method was developed to examine short-term phthalate leaching from PVC/phthalate films at the molecular level using sum frequency generation vibrational spectroscopy (SFG). Combining SFG and Fourier transform infrared spectroscopy (FTIR), surface and bulk molecular structures of PVC/phthalate films were also comprehensively evaluated during the phthalate leaching process under various environments. The leaching processes of two phthalates, diethyl phthalate (DEP) and dibutyl phthalate (DBP), from the PVC/phthalate films with various weight ratios were studied. Oxygen plasma was applied to treat the PVC/phthalate film surfaces to verify its efficacy on preventing/reducing phthalate leaching from PVC. Our results show that DBP is more stable than DEP in PVC/phthalate films. Even so, DBP molecules were still found to very slowly leach to the environment from PVC at 30 °C, at a rate much slower than DEP. Also, the bulk DBP content substantially influences the DBP leaching. Higher DBP bulk concentration yields less stable DBP molecules in the PVC matrix, allowing molecules to leach from the polymer film more easily. Additionally, DBP leaching is very sensitive to temperature changes; higher temperature can strongly enhance the leaching process. For most cases, the oxygen plasma treatment can effectively prevent phthalate leaching from PVC films (e.g., for samples with low bulk concentrations of DBP-5 and 30 wt %). It is also capable of reducing phthalate leaching from high DBP bulk concentration PVC samples (e.g., 70 wt % DBP in PVC/DBP mixture). This research develops a highly sensitive method to detect chemicals at the molecular level as well as provides surface and bulk molecular structural changes. The method developed here is general and can be applied to detect small amounts of chemical

  3. Using in-situ polymerization of conductive polymers to enhance the electrical properties of solution-processed carbon nanotube films and fibers.

    Science.gov (United States)

    Allen, Ranulfo; Pan, Lijia; Fuller, Gerald G; Bao, Zhenan

    2014-07-09

    Single-walled carbon nanotubes/polymer composites typically have limited conductivity due to a low concentration of nanotubes and the insulating nature of the polymers used. Here we combined a method to align carbon nanotubes with in-situ polymerization of conductive polymer to form composite films and fibers. Use of the conducting polymer raised the conductivity of the films by 2 orders of magnitude. On the other hand, CNT fiber formation was made possible with in-situ polymerization to provide more mechanical support to the CNTs from the formed conducting polymer. The carbon nanotube/conductive polymer composite films and fibers had conductivities of 3300 and 170 S/cm, respectively. The relatively high conductivities were attributed to the polymerization process, which doped both the SWNTs and the polymer. In-situ polymerization can be a promising solution-processable method to enhance the conductivity of carbon nanotube films and fibers.

  4. 'All-solid-state' electrochemistry of a protein-confined polymer electrolyte film.

    Science.gov (United States)

    Parthasarathy, Meera; Pillai, Vijayamohanan K; Mulla, Imtiaz S; Shabab, Mohammed; Khan, M I

    2007-12-07

    Interfacial redox behavior of a heme protein (hemoglobin) confined in a solid polymer electrolyte membrane, Nafion (a perfluoro sulfonic acid ionomer) is investigated using a unique 'all-solid-state' electrochemical methodology. The supple phase-separated structure of the polymer electrolyte membrane, with hydrophilic pools containing solvated protons and water molecules, is found to preserve the incorporated protein in its active form even in the solid-state, using UV-visible, Fluorescence (of Tryptophan and Tyrosine residues) and DRIFT (diffuse reflectance infrared Fourier transform) spectroscopy. More specifically, solid-state cyclic voltammetry and electrochemical impedance of the protein-incorporated polymer films reveal that the Fe2+-form of the entrapped protein is found to bind molecular oxygen more strongly than the native protein. In the 'all-solid-state' methodology, as there is no need to dip the protein-modified electrode in a liquid electrolyte (like the conventional electrochemical methods), it offers an easier means to study a number of proteins in a variety of polymer matrices (even biomimetic assemblies). In addition, the results of the present investigation could find interesting application in a variety of research disciplines, in addition to its fundamental scientific interest, including protein biotechnology, pharmaceutical and biomimetic chemistry.

  5. Assessment of femtosecond laser induced periodic surface structures on polymer films.

    Science.gov (United States)

    Rebollar, Esther; Vázquez de Aldana, Javier R; Martín-Fabiani, Ignacio; Hernández, Margarita; Rueda, Daniel R; Ezquerra, Tiberio A; Domingo, Concepción; Moreno, Pablo; Castillejo, Marta

    2013-07-21

    In this work we present the formation of laser induced periodic surface structures (LIPSS) on spin-coated thin films of several model aromatic polymers including poly(ethylene terephthalate), poly(trimethylene terephthalate) and poly carbonate bis-phenol A upon irradiation with femtosecond pulses of 795 and 265 nm at fluences well below the ablation threshold. LIPSS are formed with period lengths similar to the laser wavelength and parallel to the direction of the laser polarization vector. Formation of LIPSS upon IR irradiation at 795 nm, a wavelength at which the polymers absorb weakly, contrasts with the absence of LIPSS in this spectral range upon irradiation with nanosecond pulses. Real and reciprocal space characterization of LIPSS obtained by Atomic Force Microscopy (AFM) and Grazing Incidence Small Angle X-ray Scattering (GISAXS), respectively, yields well correlated morphological information. Comparison of experimental and simulated GISAXS patterns suggests that LIPSS can be suitably described considering a quasi-one-dimensional paracrystalline lattice and that irradiation parameters have an influence on the order of such a lattice. Fluorescence measurements, after laser irradiation, provide indirect information about dynamics and structure of the polymer at the molecular level. Our results indicate that the LIPSS are formed by interference of the incident and surface scattered waves. As a result of this process, heating of the polymer surface above its glass transition temperature takes place enabling LIPSS formation.

  6. Effect of transition metal salts on the initiated chemical vapor deposition of polymer thin films

    Energy Technology Data Exchange (ETDEWEB)

    Kwong, Philip; Seidel, Scott; Gupta, Malancha, E-mail: malanchg@usc.edu [Mork Family Department of Chemical Engineering and Materials Science, University of Southern California, 925 Bloom Walk, Los Angeles, California 90089 (United States)

    2015-05-15

    In this work, the effect of transition metal salts on the initiated chemical vapor deposition of polymer thin films was studied using x-ray photoelectron spectroscopy. The polymerizations of 4-vinyl pyridine and 1H,1H,2H,2H-perfluorodecyl acrylate were studied using copper(II) chloride (CuCl{sub 2}) and iron(III) chloride (FeCl{sub 3}) as the transition metal salts. It was found that the surface coverages of both poly(4-vinyl pyridine) (P4VP) and poly(1H,1H,2H,2H-perfluorodecyl acrylate) were decreased on CuCl{sub 2}, while the surface coverage of only P4VP was decreased on FeCl{sub 3}. The decreased polymer surface coverage was found to be due to quenching of the propagating radicals by the salt, which led to a reduction of the oxidation state of the metal. The identification of this reaction mechanism allowed for tuning of the effectiveness of the salts to decrease the polymer surface coverage through the adjustment of processing parameters such as the filament temperature. Additionally, it was demonstrated that the ability of transition metal salts to decrease the polymer surface coverage could be extended to the fabrication of patterned cross-linked coatings, which is important for many practical applications such as sensors and microelectronics.

  7. Atmospheric Pressure non-thermal plasmas for surface treatment of polymer films

    Science.gov (United States)

    Huang, Hsiao-Feng; Wen, Chun-Hsiang; Wei, Hsiao-Kuan; Kou, Chwung-Shan

    2006-10-01

    Interest has grown over the past few years in applying atmospheric pressure non-thermal plasmas to surface treatment. In this work, we used an asymmetric glow dielectric-barrier discharge (GDBD), at atmospheric pressure in nitrogen, to improve the surface hydrophilicity of three kinds of polymer films, biaxially oriented polypropylene (BOPP), polyimide (PI), and triacetyl cellulose (TAC). This set-up consists of two asymmetric electrodes covered by dielectrics. And to prevent the filamentary discharge occur, the frequency, gas flow rate and uniformity of gas flow distribution should be carefully controlled. The discharge performance is monitored through an oscilloscope, which is connected to a high voltage probe and a current monitor. The physical and chemical properties of polymer surfaces before and after GDBD treatment were analyzed via water contact angle (CA) measurements, atomic force microscopy (AFM), and X-ray photoelectron spectroscopy (XPS) techniques.

  8. Polarization holographic recording in Disperse Red1 doped polyurethane polymer film

    Science.gov (United States)

    Aleksejeva, J.; Gerbreders, A.; Gertners, U.; Reinfelde, M.; Teteris, J.

    2011-06-01

    In this report holographic recording of polarisation and surface relief gratings in Disperse Red 1 (DR1) doped polyurethane polymer films was studied. In this material DR1 is chemically bounded to polyurethane polymer main chain. Polarization holographic recording was performed by two orthogonal circularly polarized 532 nm laser beams. Photoinduced birefringence is a precondition for polarization holograms recording, therefore a detailed study of a photoinduced birefringence and changes of optical properties was performed. The lasers with wavelengths of 375nm, 448nm, 532 nm and 632.8 nm were used as pumping beam for sample excitation. The photoinduced birefringence Δn was measured at 532 nm and 632.8 nm wavelengths. The photoinduced birefringence dependence on the pumping beam wavelength and intensity was investigated. Surface relief grating (SRG) formation was observed during polarization holographic recording process. A profile of SRG was studied by AFM. A relationship between SRG formation and photoinduced birefringence has been discussed.

  9. Melting of a nonequilibrium vortex crystal in a fluid film with polymers : elastic versus fluid turbulence

    CERN Document Server

    Gupta, Anupam

    2016-01-01

    We perform a direct numerical simulation (DNS) of the forced, incompressible two-dimensional Navier-Stokes equation coupled with the FENE-P equations for the polymer-conformation tensor. The forcing is such that, without polymers and at low Reynolds numbers $Re$, the film attains a steady state that is a square lattice of vortices and anti-vortices. We find that, as we increase the Weissenberg number ${\\mathcal Wi}$, this lattice undergoes a series of nonequilibrium phase transitions, first to spatially distorted, but temporally steady, crystals and then to a sequence of crystals that oscillate in time, periodically, at low ${\\mathcal Wi}$, and quasiperiodically, for slightly larger ${\\mathcal Wi}$. Finally, the system becomes disordered and displays spatiotemporal chaos and elastic turbulence. We then obtain the nonequilibrium phase diagram for this system, in the ${\\mathcal Wi} - Re$ plane, and show that (a) the boundary between the crystalline and turbulent phases has a complicated, fractal-type character ...

  10. Polymer waveguide grating sensor integrated with a thin-film photodetector.

    Science.gov (United States)

    Song, Fuchuan; Xiao, Jing; Xie, Antonio Jou; Seo, Sang-Woo

    2014-01-01

    This paper presents a planar waveguide grating sensor integrated with a photodetector (PD) for on-chip optical sensing systems which are suitable for diagnostics in the field and in-situ measurements. III-V semiconductor-based thin-film PD is integrated with a polymer based waveguide grating device on a silicon platform. The fabricated optical sensor successfully discriminates optical spectral characteristics of the polymer waveguide grating from the on-chip PD. In addition, its potential use as a refractive index sensor is demonstrated. Based on a planar waveguide structure, the demonstrated sensor chip may incorporate multiple grating waveguide sensing regions with their own optical detection PDs. In addition, the demonstrated processing is based on a post-integration process which is compatible with silicon complementary metal-oxide semiconductor (CMOS) electronics. Potentially, this leads a compact, chip-scale optical sensing system which can monitor multiple physical parameters simultaneously without need for external signal processing.

  11. Layered conductive polymer on nylon membrane templates for high performance, thin-film supercapacitor electrodes

    Science.gov (United States)

    Shi, HaoTian Harvey; Naguib, Hani E.

    2016-04-01

    Flexible Thin-film Electrochemical Capacitors (ECs) are emerging technology that plays an important role as energy supply for various electronics system for both present era and the future. Intrinsically conductive polymers (ICPs) are promising pseudo-capacitive materials as they feature both good electrical conductivity and high specific capacitance. This study focuses on the construction and characterization of ultra-high surface area porous electrodes based on coating of nano-sized conductive polymer materials on nylon membrane templates. Herein, a novel nano-engineered electrode material based on nylon membranes was presented, which allows the creation of super-capacitor devices that is capable of delivering competitive performance, while maintaining desirable mechanical characteristics. With the formation of a highly conductive network with the polyaniline nano-layer, the electrical conductivity was also increased dramatically to facilitate the charge transfer process. Cyclic voltammetry and specific capacitance results showed promising application of this type of composite materials for future smart textile applications.

  12. Polymer thin-film transistor based on a high dielectric constant gate insulator

    Institute of Scientific and Technical Information of China (English)

    Lü Wen; Peng Jun-Biao; Yang Kai-Xia; Lan Lin-Feng; Niu Qiao-Li; Cao Yong

    2007-01-01

    In this paper full polymer thin-film transistors (PTFTs) based on Poly (acrylonitrile) (PAN) as the gate dielectric and poly (2-methoxy-5-(2'-ethyl-hexyloxy)-1,4-phenylene-vinylene) (MEH-PPV) as the semiconductor layer were investigated by using different channel width/length ratios. Relatively high dielectric constant of the polymer dielectric layer (6.27) can remarkably reduce the threshold voltage of the transistors to below-3 V. Hole field-effect mobility of MEH-PPV of the PTFTs was about 4.8 × 10-4 cm2/Vs, and on/off current ratio was larger than 102, which was comparable with that of transistors with widely used Poly (4-vinyl phenol) (PVP) or SiO2 as gate dielectrics.

  13. Effect of polymer/clay composition on processability of polylactide nanocomposites by film blowing

    Science.gov (United States)

    Garofalo, E.; Galdi, M. R.; D'Arienzo, L.; Di Maio, L.; Incarnato, L.

    2015-12-01

    The blown extrusion of poly(lactic acid) presents several challenges mainly due to its poor elongation properties. This work deals on the possibility to enhance the processabiliy of PLA by film blowing by functionalizing the polymer with nanosilicates. In particular, two types of polylactic acid (PLA 4032D and PLA 4042D) and different types of filler, selected from montmorillonites (Cloisite 30B) and bentonites (Nanofil SE3010) families, were used to prepare the hybrid systems by using a twin-screw extruder. The interaction between the polymer and the clay was evaluated by FTIR analysis and correlated to the structure of the obtained nanocomposites in terms of clay dispersion. All the samples were then submitted to rheological measurements both in shear and elongational mode.

  14. Spectroscopic properties of (PVA+ZnO):Mn{sup 2+} polymer films

    Energy Technology Data Exchange (ETDEWEB)

    Rani, Ch.; Raju, D. Siva; Bindu, S. Hima; Krishna, J. Suresh; Raju, Ch. Linga [Dept. of Physics, Acharya Nagarjuna University, N. Nagar-522510, A.P (India)

    2015-05-15

    Electron Paramagnetic Resonance (EPR), optical absorption and infrared spectral studies have been carried out on Mn{sup 2+} ions doped in poly(vinyl alcohol) complexed with zinc oxide polymer films prepared by solution cast technique. The EPR spectra of 1 mol% Mn{sup 2+} ions doped polymer complex (PVA+ZnO) at room temperature exhibit sextet hyperfine structure (hfs), centered at 2.01. The spin-Hamiltonian parameter values indicate that the ground state of Mn{sup 2+} ion in d{sup 5} and the site symmetry around Mn{sup 2+} ions in tetragonally distorted octa hedral site. The optical absorption spectra exhibits two bands centered at 275nm at 437nm. The FTIR spectrum exhibits bands characteristic of stretching and banding vibrations of O-H, C-H and C=C groups.

  15. Process parameters for fast production of ultra-thin polymer film with electrospray deposition under ambient conditions.

    Science.gov (United States)

    Rietveld, Ivo B; Kobayashi, Kei; Yamada, Hirofumi; Matsushige, Kazumi

    2009-11-15

    Poly(vinylidene fluoride) films between 60 and 120nm have been prepared with electrostatic spray deposition (ESD) in 25-45s. The films are robust and exhibit a strong adhesion to the substrate surface. The important electrospray parameters for ultra-thin film formation are droplet size, initial polymer concentration, shear rate at impact, and volume flux. The latter can be understood as a measure for the solvent balance between deposition and evaporation; it affects overall film quality. The droplet size determines the minimum film thickness at which continuous film forms without voids. Polymer concentration affects thin-film smoothness and below a fixed concentration threshold, films cease to appear. For the very first droplets, wetting behavior on the substrate is most important. Subsequently, shear rate determines how voids are filled up and it determines final film smoothness. In addition to the electrospray conditions, substrates that favor wetting and have a capability to conduct charges away from the surface contribute to the formation of well-defined, ultra-thin films.

  16. Bis(thienothiophenyl) diketopyrrolopyrrole-based conjugated polymers with various branched alkyl side chains and their applications in thin-film transistors and polymer solar cells.

    Science.gov (United States)

    Shin, Jicheol; Park, Gi Eun; Lee, Dae Hee; Um, Hyun Ah; Lee, Tae Wan; Cho, Min Ju; Choi, Dong Hoon

    2015-02-11

    New thienothiophene-flanked diketopyrrolopyrrole and thiophene-containing π-extended conjugated polymers with various branched alkyl side-chains were successfully synthesized. 2-Octyldodecyl, 2-decyltetradecyl, 2-tetradecylhexadecyl, 2-hexadecyloctadecyl, and 2-octadecyldocosyl groups were selected as the side-chain moieties and were anchored to the N-positions of the thienothiophene-flanked diketopyrrolopyrrole unit. All five polymers were found to be soluble owing to the bulkiness of the side chains. The thin-film transistor based on the 2-tetradecylhexadecyl-substituted polymer showed the highest hole mobility of 1.92 cm2 V(-1) s(-1) due to it having the smallest π-π stacking distance between the polymer chains, which was determined by grazing incidence X-ray diffraction. Bulk heterojunction polymer solar cells incorporating [6,6]-phenyl-C71-butyric acid methyl ester as the n-type molecule and the additive 1,8-diiodooctane (1 vol %) were also constructed from the synthesized polymers without thermal annealing; the device containing the 2-octyldodecyl-substituted polymer exhibited the highest power conversion efficiency of 5.8%. Although all the polymers showed similar physical properties, their device performance was clearly influenced by the sizes of the branched alkyl side-chain groups.

  17. Hydrodynamic effects on phase separation morphologies in evaporating thin films of polymer solutions

    Science.gov (United States)

    Zoumpouli, Garyfalia A.; Yiantsios, Stergios G.

    2016-08-01

    We examine effects of hydrodynamics on phase separation morphologies developed during drying of thin films containing a volatile solvent and two dissolved polymers. Cahn-Hilliard and Flory-Huggins theories are used to describe the free energy of the phase separating systems. The thin films, considered as Newtonian fluids, flow in response to Korteweg stresses arising due to concentration non-uniformities that develop during solvent evaporation. Numerical simulations are employed to investigate the effects of a Peclet number, defined in terms of system physical properties, as well as the effects of parameters characterizing the speed of evaporation and preferential wetting of the solutes at the gas interface. For systems exhibiting preferential wetting, diffusion alone is known to favor lamellar configurations for the separated phases in the dried film. However, a mechanism of hydrodynamic instability of a short length scale is revealed, which beyond a threshold Peclet number may deform and break the lamellae. The critical Peclet number tends to decrease as the evaporation rate increases and to increase with the tendency of the polymers to selectively wet the gas interface. As the Peclet number increases, the instability moves closer to the gas interface and induces the formation of a lateral segregation template that guides the subsequent evolution of the phase separation process. On the other hand, for systems with no preferential wetting or any other property asymmetries between the two polymers, diffusion alone favors the formation of laterally separated configurations. In this case, concentration perturbation modes that lead to enhanced Korteweg stresses may be favored for sufficiently large Peclet numbers. For such modes, a second mechanism is revealed, which is similar to the solutocapillary Marangoni instability observed in evaporating solutions when interfacial tension increases with the concentration of the non-volatile component. This mechanism may lead

  18. Viscoelastic characterization of thin-film polymers exposed to low Earth orbit

    Science.gov (United States)

    Letton, Alan; Farrow, Allan; Strganac, Thomas

    1993-01-01

    should be noted that the dependence on directionality for the polymer films was considered since these films were manufactured by a blown-film process.

  19. Random lasing in dye-doped polymer dispersed liquid crystal film

    Science.gov (United States)

    Wu, Rina; Shi, Rui-xin; Wu, Xiaojiao; Wu, Jie; Dai, Qin

    2016-09-01

    A dye-doped polymer-dispersed liquid crystal film was designed and fabricated, and random lasing action was studied. A mixture of laser dye, nematic liquid crystal, chiral dopant, and PVA was used to prepare the dye-doped polymer-dispersed liquid crystal film by means of microcapsules. Scanning electron microscopy analysis showed that most liquid crystal droplets in the polymer matrix ranged from 30 μm to 40 μm, the size of the liquid crystal droplets was small. Under frequency doubled 532 nm Nd:YAG laser-pumped optical excitation, a plurality of discrete and sharp random laser radiation peaks could be measured in the range of 575-590 nm. The line-width of the lasing peak was 0.2 nm and the threshold of the random lasing was 9 mJ. Under heating, the emission peaks of random lasing disappeared. By detecting the emission light spot energy distribution, the mechanism of radiation was found to be random lasing. The random lasing radiation mechanism was then analyzed and discussed. Experimental results indicated that the size of the liquid crystal droplets is the decisive factor that influences the lasing mechanism. The surface anchor role can be ignored when the size of the liquid crystal droplets in the polymer matrix is small, which is beneficial to form multiple scattering. The transmission path of photons is similar to that in a ring cavity, providing feedback to obtain random lasing output. Project supported by the National Natural Science Foundation of China (Grant No. 61378042), the Colleges and Universities in Liaoning Province Outstanding Young Scholars Growth Plans, China (Grant No. LJQ2015093), and Shenyang Ligong University Laser and Optical Information of Liaoning Province Key Laboratory Open Funds, China.

  20. Quantitative evaluation of evaporation rate during spin-coating of polymer blend films: Control of film structure through defined-atmosphere solvent-casting.

    Science.gov (United States)

    Mokarian-Tabari, P; Geoghegan, M; Howse, J R; Heriot, S Y; Thompson, R L; Jones, R A L

    2010-12-01

    Thin films of polymer mixtures made by spin-coating can phase separate in two ways: by forming lateral domains, or by separating into distinct layers. The latter situation (self-stratification or vertical phase separation) could be advantageous in a number of practical applications, such as polymer optoelectronics. We demonstrate that, by controlling the evaporation rate during the spin-coating process, we can obtain either self-stratification or lateral phase separation in the same system, and we relate this to a previously hypothesised mechanism for phase separation during spin-coating in thin films, according to which a transient wetting layer breaks up due to a Marangoni-type instability driven by a concentration gradient of solvent within the drying film. Our results show that rapid evaporation leads to a laterally phase-separated structure, while reducing the evaporation rate suppresses the interfacial instability and leads to a self-stratified final film.

  1. Facility and Methods Developed for Simulated Space Vacuum Ultraviolet Exposure Testing of Polymer Films

    Science.gov (United States)

    Dever, Joyce A.; Pietromica, Anthony J.; Stueber, Thomas J.; Sechkar, Edward A.; Messer, Russell K.

    2002-01-01

    Vacuum ultraviolet (VUV) radiation of wavelengths between 115 and 200 nm produced by the Sun in the space environment can degrade polymer films, producing changes in their optical, mechanical, and chemical properties. These effects are particularly important for thin polymer films being considered for ultralightweight space structures, because, for most polymers, VUV radiation is absorbed in a thin surface layer. The NASA Glenn Research Center has developed facilities and methods for long-term ground testing of polymer films to evaluate space environmental VUV radiation effects. VUV exposure can also be used as part of combined or sequential simulated space environmental exposures to determine combined damaging effects with other aspects of the space environment, which include solar ultraviolet radiation, solar flare x-rays, electron and proton radiation, atomic oxygen (for low-Earth-orbit missions), and temperature effects. Because the wavelength sensitivity of VUV damage is not well known for most materials, Glenn's VUV facility uses a broad-spectrum deuterium lamp with a magnesium fluoride window that provides output between 115 and 200 nm. Deuterium lamps of this type were characterized by the National Institute of Standards and Technology and through measurements at Glenn. Spectral irradiance measurements show that from approximately 115 to 160 nm, deuterium lamp irradiance can be many times that of air mass zero solar irradiance, and as wavelength increases above approximately 160 nm, deuterium lamp irradiance decreases in comparison to the Sun. The facility is a cryopumped vacuum chamber that achieves a system pressure of approximately 5310(exp -6) torr. It contains four individual VUV-exposure compartments in vacuum, separated by water-cooled copper walls to minimize VUV radiation and any sample contamination cross interactions between compartments. Each VUV-exposure compartment contains a VUV deuterium lamp, a motor-controlled sample stage coupled with a

  2. Growth of thin Al{sub 2}O{sub 3} films on biaxially oriented polymer films by atomic layer deposition

    Energy Technology Data Exchange (ETDEWEB)

    Vaehae-Nissi, Mika, E-mail: mika.vaha-nissi@vtt.fi [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT (Finland); Kauppi, Emilia, E-mail: emilia.kauppi@vti.fi [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT (Finland); Sahagian, Khoren, E-mail: khoren@anasysinstruments.com [Anasys Instruments, 121 Gray Avenue, Suite 100, Santa Barbara, CA 93101 (United States); Johansson, Leena-Sisko, E-mail: leena-sisko.johansson@aalto.fi [Aalto University, School of Chemical Technology, Department of Forest Products Technology, P.O. Box 16100, FI-00076 AALTO (Finland); Peresin, Maria Soledad; Sievaenen, Jenni; Harlin, Ali [VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT (Finland)

    2012-11-01

    The effects of thin film nucleation and initial growth on roughness, chemistry and thermomechanical properties of polymer film surfaces were studied. Al{sub 2}O{sub 3} was deposited onto commercial biaxially oriented polypropylene and polylactic acid films at 80 Degree-Sign C by using atomic layer deposition technique. Both substrates, especially the more hydrophobic polypropylene, showed initial growth through Al{sub 2}O{sub 3} clusters. There was a faster deposition of Al{sub 2}O{sub 3} on polylactic acid film than on polypropylene at the early stages of the Al{sub 2}O{sub 3} deposition. There were also indications of chemical interactions between polylactic acid and trimethyl aluminum used as a precursor for Al{sub 2}O{sub 3}. Changes in the thermo-mechanical properties of the polymer surfaces with Al{sub 2}O{sub 3} also evidenced the differences between the substrate polymer films. The near surface interphase formed in polylactic acid probably contributed to the strong increase and scattering in the softening temperature during the early thin film growth. - Highlights: Black-Right-Pointing-Pointer Growth of atomic layer deposited Al{sub 2}O{sub 3} at 80 Degree-Sign C was studied on commercial films. Black-Right-Pointing-Pointer Both substrate films showed early Al{sub 2}O{sub 3} growth through clusters. Black-Right-Pointing-Pointer Initial growth rate depends on the nature of the substrate film surface. Black-Right-Pointing-Pointer There were indications of chemical interactions between substrate and precursor. Black-Right-Pointing-Pointer Film thickness and chemical interactions affect thermo-mechanical properties.

  3. [Synthesis and Characterization of a Sugar Based Electrolyte for Thin-film Polymer Batteries

    Science.gov (United States)

    1998-01-01

    The work performed during the current renewal period, March 1,1998 focused primarily on the synthesis and characterization of a sugar based electrolyte for thin-film polymer batteries. The initial phase of the project involved developing a suitable sugar to use as the monomer in the polymeric electrolyte synthesis. The monomer has been synthesized and characterized completely. Overall the yield of this material is high and it can be produced in relatively large quantity easily and in high purity. The scheme used for the preparation of the monomer is outlined along with pertinent yields.

  4. Electrochemical Synthesis of a Microporous Conductive Polymer Based on a Metal-Organic Framework Thin Film

    KAUST Repository

    Lu, Chunjing

    2014-05-22

    A new approach to preparing 3D microporous conductive polymer has been demonstrated in the electrochemical synthesis of a porous polyaniline network with the utilization of a MOF thin film supported on a conducting substrate. The prepared porous polyaniline with well-defined uniform micropores of 0.84 nm exhibits a high BET surface area of 986 m2 g−1 and a high electric conductivity of 0.125 S cm−1 when doped with I2, which is superior to existing porous conducting materials of porous MOFs, CMPs, and COFs.

  5. Organic Thin-Film Transistors with Phase Separation of Polymer-Blend Small-Molecule Semiconductors: Dependence on Molecular Weight and Types of Polymer

    Science.gov (United States)

    Ohe, Takahiro; Kuribayashi, Miki; Tsuboi, Ami; Satori, Kotaro; Itabashi, Masao; Nomoto, Kazumasa

    2009-12-01

    We have investigated effect of polymer on solution-processed organic thin-film transistors (TFTs) with polymer-blend semiconductors. Organic TFTs made from a solution of 6,13-bis(triisopropylsilylethynyl)-pentacene with a poly(α-methylstyrene) (PaMS) molecular weight of 20 k or above, exhibited mobility around 0.1 cm2/(V.s). On the other hand, the organic TFTs with a PaMS molecular weight of 2 k or with a poly(isobutyl methacrylate), exhibited much lower mobility. This can be explained in terms of the structure and crystallinity of the films. The results of film structure can be explained by applying the Flory-Huggins theory.

  6. Crack density and electrical resistance in indium-tin-oxide/polymer thin films under cyclic loading

    KAUST Repository

    Mora Cordova, Angel

    2014-11-01

    Here, we propose a damage model that describes the degradation of the material properties of indium-tin-oxide (ITO) thin films deposited on polymer substrates under cyclic loading. We base this model on our earlier tensile test model and show that the new model is suitable for cyclic loading. After calibration with experimental data, we are able to capture the stress-strain behavior and changes in electrical resistance of ITO thin films. We are also able to predict the crack density using calibrations from our previous model. Finally, we demonstrate the capabilities of our model based on simulations using material properties reported in the literature. Our model is implemented in the commercially available finite element software ABAQUS using a user subroutine UMAT.[Figure not available: see fulltext.].

  7. Flexible, thin films of graphene-polymer composites for EMI shielding

    Science.gov (United States)

    Jan, Rahim; Habib, Amir; Aftab Akram, Muhammad; Ahmad, Imtiaz; Shah, Attaullah; Sadiq, Muhammad; Hussain, Akhtar

    2017-03-01

    Liquid-phase-exfoliated, pristine graphene nanosheets (GNSs) are dispersed in thermoplastic polyurethane (TPU) to obtain free-standing conducting composite films. The composites are tested for electromagnetic interference (EMI) shielding applications in the X-band (8-12 GHz). A constant increase in the electromagnetic attenuation is observed as a function of GNS loading (0-0.12 V f). The EMI shielding effectiveness of about 1 dB for the neat polymer is enhanced to about 14 dB at 0.12 V f GNS as the electromagnetic energy is dissipated due to the GNS conducting network formed inside. Conducting behavior of GNS-TPU composites is confirmed by electrical conductivity measurements along with cyclic voltammetry as the band gap is reduced with a graphene increment. Scanning electron microscopy predicts a homogeneous dispersion of GNS inside composites. For such thin composite films (0.03-0.05 mm), the EMI shielding effectiveness is considerable.

  8. High-performance ferroelectric memory based on phase-separated films of polymer blends

    KAUST Repository

    Khan, Mohammad A.

    2013-10-29

    High-performance polymer memory is fabricated using blends of ferroelectric poly(vinylidene-fluoride-trifluoroethylene) (P(VDF-TrFE)) and highly insulating poly(p-phenylene oxide) (PPO). The blend films spontaneously phase separate into amorphous PPO nanospheres embedded in a semicrystalline P(VDF-TrFE) matrix. Using low molecular weight PPO with high miscibility in a common solvent, i.e., methyl ethyl ketone, blend films are spin cast with extremely low roughness (Rrms ≈ 4.92 nm) and achieve nanoscale phase seperation (PPO domain size < 200 nm). These blend devices display highly improved ferroelectric and dielectric performance with low dielectric losses (<0.2 up to 1 MHz), enhanced thermal stability (up to ≈353 K), excellent fatigue endurance (80% retention after 106 cycles at 1 KHz) and high dielectric breakdown fields (≈360 MV/m). © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Deposition of calcium carbonate films by a polymer-induced liquid-precursor (PILP) process

    Science.gov (United States)

    Gower, Laurie B.; Odom, Damian J.

    2000-03-01

    A polypeptide additive has been used to transform the solution crystallization of calcium carbonate to a solidification process of a liquid-phase mineral precursor. In situ observations reveal that polyaspartate induces liquid-liquid phase separation of droplets of a mineral precursor. The droplets deposit on the substrate and coalesce to form a coating, which then solidifies into calcitic tablets and films. Transition bars form during the amorphous to crystalline transition, leading to sectorization of calcite tablets, and the defect textures and crystal morphologies are atypical of solution grown crystals. The formation of nonequilibrium crystal morphologies using an acidic polypeptide may have implications in the field of biomineralization, and the environmentally friendly aspects of this polymer-induced liquid-precursor (PILP) process may offer new techniques for aqueous-based processing of ceramic films, coatings, and particulates.

  10. Tunable Gas Permeability of Polymer-Clay Nano Brick Wall Thin Film Assemblies

    Science.gov (United States)

    Gamboa, Daniel; Priolo, Morgan; Grunlan, Jaime

    2010-03-01

    Thin films of anionic natural montmorrilonite (MMT) clay and cationic polyethylenimine (PEI) have been produced by alternately dipping a plastic substrate into dilute aqueous mixtures containing each ingredient. After 40 polymer-clay layers have been deposited, the resulting transparent film exhibits an oxygen transmission rate (OTR) below 0.35 cm^3/m^2 . day when the pH of PEI solution is 10. This low permeability is due to a brick wall nanostructure comprised of completely exfoliated clay bricks in polymeric mortar. This brick wall creates an extremely tortuous path at thicknesses below 250 nm and clay concentration above 80 wt%. A 70-bilayer PEI-MMT assembly has an undetectable OTR (packaging and foil replacement for food.

  11. Solvent-Free Patterning of Colloidal Quantum Dot Films Utilizing Shape Memory Polymers

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    Hohyun Keum

    2017-01-01

    Full Text Available Colloidal quantum dots (QDs with properties that can be tuned by size, shape, and composition are promising for the next generation of photonic and electronic devices. However, utilization of these materials in such devices is hindered by the limited compatibility of established semiconductor processing techniques. In this context, patterning of QD films formed from colloidal solutions is a critical challenge and alternative methods are currently being developed for the broader adoption of colloidal QDs in functional devices. Here, we present a solvent-free approach to patterning QD films by utilizing a shape memory polymer (SMP. The high pull-off force of the SMP below glass transition temperature (Tg in conjunction with the conformal contact at elevated temperatures (above Tg enables large-area, rate-independent, fine patterning while preserving desired properties of QDs.

  12. Dropwise Condensation of Low Surface Tension Fluids on iCVD Grafted Polymer Films

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    Khalil, Karim; Gleason, Karen; Varanasi, Kripa

    2016-11-01

    A large majority of the work devoted to surface engineering for promoting dropwise condensation heat transfer has focused on steam. Much less attention has been dedicated to the condensation of low surface tension fluids such as hydrocarbons, cryogens, and fluorinated refrigerants, which are used in several industrial applications, including LNG storage and organic Rankine cycles used for heat recovery from low temperature sources such as biomass combustion, industrial waste, or geothermal heat sources. Most hydrophobic modifiers used previously to promote dropwise condensation are silane-based monolayers that have been shown to rapidly degrade under industrial conditions. Here we investigate condensation behavior of a variety of low surface tension liquids on durable covalently-grafted polymer films deposited using initiated chemical vapor deposition (iCVD) on metals such as titanium. We observe a four to seven-fold improvement in the vapor-side heat transfer coefficient by promoting dropwise condensation of low surface tension fluids on these stable films.

  13. Mapping a plasmonic hologram with photosensitive polymer films: standing versus propagating waves.

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    Papke, Thomas; Yadavalli, Nataraja Sekhar; Henkel, Carsten; Santer, Svetlana

    2014-08-27

    We use a photosensitive layer containing azobenzene moieties to map near-field intensity patterns in the vicinity of nanogrids fabricated within a thin silver layer. It is known that azobenzene containing films deform permanently during irradiation, following the pattern of the field intensity. The photosensitive material reacts only to stationary waves whose intensity patterns do not change in time. In this study, we have found a periodic deformation above the silver film outside the nanostructure, even if the latter consists of just one groove. This is in contradiction to the widely accepted viewpoint that propagating surface plasmon modes dominate outside nanogrids. We explain our observation based on an electromagnetic hologram formed by the constructive interference between a propagating surface plasmon wave and the incident light. This hologram contains a stationary intensity and polarization grating that even appears in the absence of the polymer layer.

  14. Sub-nanometer expansions of redox responsive polymer films monitored by imaging ellipsometry.

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    Cumurcu, Aysegul; Feng, Xueling; Ramos, Lionel Dos; Hempenius, Mark A; Schön, Peter; Vancso, G Julius

    2014-10-21

    We describe a novel approach to quantitatively visualize sub nm height changes occurring in thin films of redox active polymers upon reversible electrochemical oxidation/reduction in situ and in real-time with electrochemical imaging ellipsometry (EC-IE). Our approach is based on the utilization of a micro-patterned substrate containing circular patterns of passive (non-redox active) 11-mercapto-1-undecanol (MCU) within a redox-responsive oligoethylene sulfide end-functionalized poly(ferrocenyldimethylsilane) (ES-PFS) film on a gold substrate. The non-redox responsive MCU layer was used as a molecular reference layer for the direct visualization of the minute thickness variations of the ES-PFS film. The ellipsometric microscopy images were recorded in aqueous electrolyte solutions at potentials of -0.1 V and 0.6 V vs. Ag/AgCl corresponding to the reduced and oxidized redox states of ES-PFS, respectively. The ellipsometric contrast images showed a 37 (±2)% intensity increase in the ES-PFS layer upon oxidation. The thickness of the ES-PFS layer reversibly changed between 4.0 (±0.1) nm and 3.4 (±0.1) nm upon oxidation and reduction, respectively, as determined by IE. Additionally, electrochemical atomic force microscopy (EC-AFM) was used to verify the redox controlled thickness variations. The proposed method opens novel avenues to optically visualize minute and rapid height changes occurring e.g. in redox active (and other stimulus responsive) polymer films in a fast and non-invasive manner.

  15. Warpage Analysis of Electroplated Cu Films on Fiber-Reinforced Polymer Packaging Substrates

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    Cheolgyu Kim

    2015-06-01

    Full Text Available This paper presents a warpage analysis method that predicts the warpage behavior of electroplated Cu films on glass fiber-reinforced polymer (GFRP packaging substrates. The analysis method is performed using the following sequence: fabricate specimens for scanning 3D contours, transform 3D data into curvatures, compute the built-in stress of the film using a stress-curvature analytic model, and verify it through comparisons of the finite element method (FEM simulations with the measured data. The curvature is used to describe the deflection and warpage modes and orientations of the specimen. Two primary factors that affect the warpage behavior of the electroplated Cu film on FRP substrate specimens are investigated. The first factor is the built-in stress in a Cu film that explains the room temperature warpage of the specimen under no thermal process. The second factor is the misfit of the coefficient of thermal expansion (CTE between the Cu and FRP layer, which is a dominant factor during the temperature change. The calculated residual stress, and predicted curvatures using FEM simulation throughout the reflow process temperature range between 25 and 180 °C are proven to be accurate by the comparison of the FEM simulations and experiment measurements.

  16. Energetic-assisted scanning thermal lithography for patterning silver nanoparticles in polymer films.

    Science.gov (United States)

    Huang, Chun-Min; Yeh, Chung-Hsien; Chen, Lung; Huang, De-An; Kuo, Changshu

    2013-01-01

    Energetic-assisted scanning thermal lithography (SThL) was demonstrated with the addition of benzoyl peroxide (BPO) for patterning silver nanoparticles. SThL samples were prepared by spin-coating poly(methyl methacrylate) (PMMA) thin films preloaded with BPO and silver nitrate precursors. Localized thermal analysis via probe heating demonstrated that the BPO decomposition in the polymer film took place at the temperature of 80 °C. Above this temperature, the thermal probe initiated the decomposition of the peroxide, which resulted in the in situ discharge of exothermal energy to compensate the joule shortage and the rapid cooling in the SThL thin film samples. The additional joule energy thermally enhanced the synthesis of silver nanoparticles, which were patterned and embedded in the PMMA thin film. Surface plasmon resonance scattering of these silver nanoparticles was observed by dark-field optical microscopy, whereas the nanoparticle distribution was examined by transmission electron microscopy. Variations in the scanning probe temperatures and peroxide concentrations were carefully investigated to optimize the thermal lithography efficiency upon the addition of energetics.

  17. Laser-induced in situ synthesis of Pd and Pt nanoparticles on polymer films

    Science.gov (United States)

    Mehrabanian, Mehran; Morselli, Davide; Caputo, Gianvito; Scarpellini, Alice; Palazon, Francisco; Athanassiou, Athanassia; Fragouli, Despina

    2016-12-01

    We present the localized in situ formation of Pd and Pt nanoparticles embedded in chitosan solid films. This is achieved by the photo-induced reduction of metallic precursors, previously incorporated in chitosan films, through controlled UV pulsed laser irradiation. Interestingly, at high number of laser pulses, Pd and Pt follow different formation pathways, contrary to their common photoreduction mechanism occurring at low irradiation pulses. Specifically, in the case of the Pd, a photofragmentation process takes place fracturing the previously formed nanoparticles into smaller ones; whereas in the case of Pt, the prolonged irradiation promotes the nanoparticles agglomeration. The combination of both precursors in a binary solid system results in the combined formation of both Pd and Pt nanoparticles in the polymer film upon laser irradiation. The herein reported approach is an efficient and precise tool to generate size- and density-controlled Pd and Pt nanoparticles in desired areas of polymeric films, rendering this method a potential candidate for the fabrication of flexible polymeric devices for gas-sensing or electro-catalysis applications.

  18. Laser-processing of VO2 thin films synthesized by polymer-assisted-deposition

    Science.gov (United States)

    Breckenfeld, Eric; Kim, Heungsoo; Gorzkowski, Edward P.; Sutto, Thomas E.; Piqué, Alberto

    2017-03-01

    We investigate a novel route for synthesis and laser-sintering of VO2 thin films via solution-based polymer-assisted-deposition (PAD). By replacing the traditional solvent for PAD (water) with propylene glycol, we are able to control the viscosity and improve the environmental stability of the precursor. The solution stability and ability to control the viscosity makes for an ideal solution to pattern simple or complex shapes via direct-write methods. We demonstrate the potential of our precursor for printing applications by combining PAD with laser induced forward transfer (LIFT). We also demonstrate large-area film synthesis on 4 in. diameter glass wafers. By varying the annealing temperature, we identify the optimal synthesis conditions, obtaining optical transmittance changes of 60% at a 2500 nm wavelength and a two-order-of-magnitude semiconductor-to-metal transition. We go on to demonstrate two routes for improved semiconductor-to-metal characteristics. The first method uses a multi-coating process to produce denser films with large particles. The second method uses a pulsed-UV-laser sintering step in films annealed at low temperatures (<450° C) to promote particle growth and improve the semiconductor-to-metal transition. By comparing the hysteresis width and semiconductor-to-metal transition magnitude in these samples, we demonstrate that both methods yield high quality VO2 with a three-order-of-magnitude transition.

  19. Carbon Nanotube/Conductive Additive/Space Durable Polymer Nanocomposite Films for Electrostatic Charge Dissipation

    Science.gov (United States)

    Smith, Joseph G., Jr.; Watson, Kent A.; Delozier, Donavon M.; Connell, John W.

    2003-01-01

    Thin film membranes of space environmentally stable polymeric materials possessing low color/solar absorptivity (alpha) are of interest for potential applications on Gossamer spacecraft. In addition to these properties, sufficient electrical conductivity is required in order to dissipate electrostatic charge (ESC) build-up brought about by the charged orbital environment. One approach to achieve sufficient electrical conductivity for ESC mitigation is the incorporation of single wall carbon nanotubes (SWNTs). However, when the SWNTs are dispersed throughout the polymer matrix, the nanocomposite films tend to be significantly darker than the pristine material resulting in a higher alpha. The incorporation of conductive additives in combination with a decreased loading level of SWNTs is one approach for improving alpha while retaining conductivity. Taken individually, the low loading level of conductive additives and SWNTs is insufficient in achieving the percolation level necessary for electrical conductivity. When added simultaneously to the film, conductivity is achieved through a synergistic effect. The chemistry, physical, and mechanical properties of the nanocomposite films will be presented.

  20. Biodegradable polymer films from seaweed polysaccharides: A review on cellulose as a reinforcement material

    Directory of Open Access Journals (Sweden)

    H. P. S. Abdul Khalil

    2017-04-01

    Full Text Available Seaweed and cellulose are promising natural polymers. This article reviews the basic information and recent developments of both seaweed and cellulose biopolymer materials as well as analyses the feasible formation of seaweed/cellulose composite films. Seaweed and cellulose both exhibit interesting film-forming properties. Nevertheless, seaweed has poor water vapour barrier and mechanical properties, whereas cellulose is neither meltable nor soluble in water or common organic solvents due to its highly crystalline structure. Therefore, modification of these hydrocolloids has been done to exploit their useful properties. Blending of biopolymers is a must recommended approach to improve the desired characteristics. From the review, seaweed is well compatible with cellulose, which possesses excellent mechanical strength and water resistance properties. Moreover, seaweed/cellulose composite films can prolong a product’s shelf life while maintaining its biodegradability. Additionally, the films show potential in contributing to the bioeconomy. In order to widen seaweed and cellulose in biocomposite application across various industries, some of the viewpoints are highlighted to be focused for future developments and applications.