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Sample records for conjugated polymers application

  1. Nanostructured conjugated polymers in chemical sensors: synthesis, properties and applications.

    Science.gov (United States)

    Correa, D S; Medeiros, E S; Oliveira, J E; Paterno, L G; Mattoso, Luiz C

    2014-09-01

    Conjugated polymers are organic materials endowed with a π-electron conjugation along the polymer backbone that present appealing electrical and optical properties for technological applications. By using conjugated polymeric materials in the nanoscale, such properties can be further enhanced. In addition, the use of nanostructured materials makes possible miniaturize devices at the micro/nano scale. The applications of conjugated nanostructured polymers include sensors, actuators, flexible displays, discrete electronic devices, and smart fabric, to name a few. In particular, the use of conjugated polymers in chemical and biological sensors is made feasible owning to their sensitivity to the physicochemical conditions of its surrounding environment, such as chemical composition, pH, dielectric constant, humidity or even temperature. Subtle changes in these conditions bring about variations on the electrical (resistivity and capacitance), optical (absorptivity, luminescence, etc.), and mechanical properties of the conjugated polymer, which can be precisely measured by different experimental methods and ultimately associated with a specific analyte and its concentration. The present review article highlights the main features of conjugated polymers that make them suitable for chemical sensors. An especial emphasis is given to nanostructured sensors systems, which present high sensitivity and selectivity, and find application in beverage and food quality control, pharmaceutical industries, medical diagnosis, environmental monitoring, and homeland security, and other applications as discussed throughout this review.

  2. Nanostructured Conjugated Polymers for Energy-Related Applications beyond Solar Cells.

    Science.gov (United States)

    Xie, Jian; Zhao, Cui-E; Lin, Zong-Qiong; Gu, Pei-Yang; Zhang, Qichun

    2016-05-20

    To meet the ever-increasing requirements for the next generation of sustainable and versatile energy-related devices, conjugated polymers, which have potential advantages over small molecules and inorganic materials, are among the most promising types of green candidates. The properties of conjugated polymers can be tuned through modification of the structure and incorporation of different functional moieties. In addition, superior performances can be achieved as a result of the advantages of nanostructures, such as their large surface areas and the shortened pathways for charge transfer. Therefore, nanostructured conjugated polymers with different properties can be obtained to be applied in different energy-related organic devices. This review focuses on the application and performance of the recently reported nanostructured conjugated polymers for high-performance devices, including rechargeable lithium batteries, microbial fuel cells (MFCs), thermoelectric generators, and photocatalytic systems. The design strategies, reaction mechanisms, advantages, and limitations of nanostructured conjugated polymers are further discussed in each section. Finally, possible routes to improve the performances of the current systems are also included in the conclusion. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Bio-degradable highly fluorescent conjugated polymer nanoparticles for bio-medical imaging applications.

    Science.gov (United States)

    Repenko, Tatjana; Rix, Anne; Ludwanowski, Simon; Go, Dennis; Kiessling, Fabian; Lederle, Wiltrud; Kuehne, Alexander J C

    2017-09-07

    Conjugated polymer nanoparticles exhibit strong fluorescence and have been applied for biological fluorescence imaging in cell culture and in small animals. However, conjugated polymer particles are hydrophobic and often chemically inert materials with diameters ranging from below 50 nm to several microns. As such, conjugated polymer nanoparticles cannot be excreted through the renal system. This drawback has prevented their application for clinical bio-medical imaging. Here, we present fully conjugated polymer nanoparticles based on imidazole units. These nanoparticles can be bio-degraded by activated macrophages. Reactive oxygen species induce scission of the conjugated polymer backbone at the imidazole unit, leading to complete decomposition of the particles into soluble low molecular weight fragments. Furthermore, the nanoparticles can be surface functionalized for directed targeting. The approach opens a wide range of opportunities for conjugated polymer particles in the fields of medical imaging, drug-delivery, and theranostics.Conjugated polymer nanoparticles have been applied for biological fluorescence imaging in cell culture and in small animals, but cannot readily be excreted through the renal system. Here the authors show fully conjugated polymer nanoparticles based on imidazole units that can be bio-degraded by activated macrophages.

  4. Near-infrared (NIR) emitting conjugated polymers for biomedical applications (Presentation Recording)

    Science.gov (United States)

    Repenko, Tatjana; Kuehne, Alexander J. C.

    2015-10-01

    Fluorescent biomedical markers of today such as dye-infiltrated colloids, microgels and quantum dots suffer from fast bleaching, lack surface functionality (for targets or pharmaceutical agents) and potentially leach heavy metals in case of quantum dots (e.g. Cd). By contrast, conjugated polymer particles are non-cytotoxic, exhibit reduced bleaching, as the entire particle consists of fluorophore, they are hydrophobic and show high quantum yields. Consequently, conjugated polymer particles represent ideal materials for biological applications and imaging. However currently, conjugated polymer particles for biomedical imaging usually lack near-infrared (NIR) emission and are polydisperse. Fluorescent agents with emission in the NIR spectrum are interesting for biomedical applications due to their low photo-damage towards biological species and the ability of NIR radiation to penetrate deep into biological tissue.. I will present the development and synthesis of new conjugated polymers particles with fluorescence in the NIR spectral region for bio-imaging and clinical diagnosis. The particle synthesis proceeds in a one-step Pd or Ni-catalyzed dispersion polymerization of functional NIR emitters. The resulting monodisperse conjugated polymer particles are obtained as a dispersion in a non-hazardous solvent. Different sizes in the sub-micrometer range with a narrow size distribution can be produced. Furthermore biological recognition motifs can be easily attached to the conjugated polymers via thiol-yne click-chemistry providing specific tumor targeting without quenching of the fluorescence. References [1] Kuehne AJC, Gather MC, Sprakel J., Nature Commun. 2012, 3, 1088. [2] Repenko T, Fokong S, De Laporte L, Go D, Kiessling F, Lammers T, Kuehne AJC.,Chem Commun 2015, accepted.

  5. Conjugated Polymer Solar Cells

    National Research Council Canada - National Science Library

    Paraschuk, Dmitry Y

    2006-01-01

    This report results from a contract tasking Moscow State University as follows: Conjugated polymers are promising materials for many photonics applications, in particular, for photovoltaic and solar cell devices...

  6. Thermo-cleavable solvents for printing conjugated polymers: Application in polymer solar cells

    DEFF Research Database (Denmark)

    Jørgensen, Mikkel; Hagemann, Ole; Alstrup, Jan

    2009-01-01

    large-scale production of polymer solar cells using screen printing. Screen-printed solar cells are still very inferior to state of the art P3HT/PCBM technology, but it is our view that it is necessary to explore these printing technologies if polymer solar cells are to ever become commercial products.......The synthesis and characterization of a number of so-called thermo-cleavable solvents are described with their application in all-air, all-solution and all-screen-printed polymer solar cells. These solvents were developed to meet some requirements for printing techniques such as long “open time...... (TGA) and high-temperature NMR established the onset temperature of decomposition, the rate of the reaction and the nature of the products. Printing experiments with inks based on these solvents together with conjugated polymers are exemplified for polymer solar cell devices to show how they enable...

  7. Conjugated Polymers for Flexible Energy Harvesting and Storage.

    Science.gov (United States)

    Zhang, Zhitao; Liao, Meng; Lou, Huiqing; Hu, Yajie; Sun, Xuemei; Peng, Huisheng

    2018-03-01

    Since the discovery of conjugated polymers in the 1970s, they have attracted considerable interest in light of their advantages of having a tunable bandgap, high electroactivity, high flexibility, and good processability compared to inorganic conducting materials. The above combined advantages make them promising for effective energy harvesting and storage, which have been widely studied in recent decades. Herein, the key advancements in the use of conjugated polymers for flexible energy harvesting and storage are reviewed. The synthesis, structure, and properties of conjugated polymers are first summarized. Then, their applications in flexible polymer solar cells, thermoelectric generators, supercapacitors, and lithium-ion batteries are described. The remaining challenges are then discussed to highlight the future direction in the development of conjugated polymers. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Polymers for Protein Conjugation

    Directory of Open Access Journals (Sweden)

    Gianfranco Pasut

    2014-01-01

    Full Text Available Polyethylene glycol (PEG at the moment is considered the leading polymer for protein conjugation in view of its unique properties, as well as to its low toxicity in humans, qualities which have been confirmed by its extensive use in clinical practice. Other polymers that are safe, biodegradable and custom-designed have, nevertheless, also been investigated as potential candidates for protein conjugation. This review will focus on natural polymers and synthetic linear polymers that have been used for protein delivery and the results associated with their use. Genetic fusion approaches for the preparation of protein-polypeptide conjugates will be also reviewed and compared with the best known chemical conjugation ones.

  9. Conjugated polymer zwitterions and solar cells comprising conjugated polymer zwitterions

    Science.gov (United States)

    Emrick, Todd; Russell, Thomas; Page, Zachariah; Liu, Yao

    2018-06-05

    A conjugated polymer zwitterion includes repeating units having structure (I), (II), or a combination thereof ##STR00001## wherein Ar is independently at each occurrence a divalent substituted or unsubstituted C3-30 arylene or heteroarylene group; L is independently at each occurrence a divalent C1-16 alkylene group, C6-30arylene or heteroarylene group, or alkylene oxide group; and R1 is independently at each occurrence a zwitterion. A polymer solar cell including the conjugated polymer zwitterion is also disclosed.

  10. Photoluminescence in conjugated polymers

    International Nuclear Information System (INIS)

    Furst, J.E.; Laugesen, R.; Dastoor, P.; McNeill, C.

    2002-01-01

    Full text: Conjugated polymers combine the electronic and optical properties of semiconductors with the processability of polymers. They contain a sequence of alternate single and double carbon bonds so that the overlap of unhybridised p z orbitals creates a delocalised ρ system which gives semiconducting properties with p-bonding (valence) and p* -antibonding (conduction) bands. Photoluminesence (PL) in conjugated polymers results from the radiative decay of singlet excitons confined to a single chain. The present work is the first in a series of studies in our laboratory that will characterize the optical properties of conjugated polymers. The experiment involves the illumination of thin films of conjugated polymer with UV light (I=360 nm) and observing the subsequent fluorescence using a custom-built, fluorescence spectrometer. Photoluminesence spectra provide basic information about the structure of the polymer film. A typical spectrum is shown in the accompanying figure. The position of the first peak is related to the polymer chain length and resolved multiple vibronic peaks are an indication of film structure and morphology. We will also present results related to the optical degradation of these materials when exposed to air and UV light

  11. Micelle-like nanoassemblies based on polymer-drug conjugates as an emerging platform for drug delivery.

    Science.gov (United States)

    Liu, Zhihong; Wang, Yutao; Zhang, Na

    2012-07-01

    During the past decades, polymer-drug conjugates are one of the hottest topics in novel drug development fields. Amphiphilic polymer-drug conjugates in aqueous solution could form micelles or micelle-like nanoassemblies. Compared with polymer-drug conjugates and the micelles into which drugs are physically entrapped, micelles or micelle-like nanoassemblies based on polymer-drug conjugates bring several additional advantages, including increased drug-loading capacity, enhanced intracellular uptake, reduced systemic toxicity, and improved therapeutic efficacy. This review focuses on recent progress achieved in the research field of micelles or micelle-like nanoassemblies based on polymer-drug conjugates. Firstly, properties of polymers, drugs, and linkers which could be used to build polymer-drug conjugate micelles or micelle-like nanoassemblies are summarized. Then, the characterization methods are described. Finally, the drug-targeting mechanisms are discussed. Micelles or micelle-like nanoassemblies based on polymer-drug conjugates as an emerging platform have the potential to achieve medical treatments with enhanced therapeutic effect. The application of micelles or micelle-like nanoassemblies based on polymer-drug conjugates may give new life to old active compounds abandoned due to their low solubility problems. For clinical application, there is a need to further optimize the properties of the polymer, drug, and linker.

  12. Synthesis of Donor-Acceptor Conjugated Polymers by "CLICK" Polymerization for OPV applications

    DEFF Research Database (Denmark)

    Brandt, Rasmus Guldbæk; Yu, Donghong

    The intent of this study was to utilize the Copper(I)-catalyzed Azide Alkyne Cycloaddition (CuAAC) as a polymerization technique (“Click” Polymerization) for synthesizing novel π-conjugated low band gap polymers for organic photovoltaic applications (OPV). The chosen approach was to synthesize...... an alternating electron donating (donor, D) and electron withdrawing (acceptor, A) co-polymer. The chosen monomers were well known units, and the novelty lies in using the monomer units with the click methodology. An insoluble alternating copolymer consisting of 2,7-diazido-9,9-dioctyl-9Hflourene and 1...

  13. Non-classical light emission from single conjugated polymers

    Science.gov (United States)

    Hollars, Christopher; Lane, Stephen; Huser, Thomas

    2002-03-01

    Photon-antibunching from single, isolated molecules of collapsed-chain poly[2-methoxy,5-(2’-ethyl-hexyloxy)-p-phenylene-vinylene] (MEH-PPV) has been observed using confocal microscopy techniques. Efficient inter-segment energy transfer in collapsed-chain conjugated polymers leads to emission from an average of only 2-3 active sites on a polymer chain that is composed of hundreds of quasi-chromophores. These few centers consist of the segments with the lowest excitation energy and are supplied by the efficient light-harvesting and energy transfer of the surrounding higher-energy segments. This effect depends on the conformation of the polymer molecules, which is controlled by solvent polarity. These results provide new insight into the controversial photophysics of conjugated polymers and their application in optoelectronic devices.

  14. Molecular design toward highly efficient photovoltaic polymers based on two-dimensional conjugated benzodithiophene.

    Science.gov (United States)

    Ye, Long; Zhang, Shaoqing; Huo, Lijun; Zhang, Maojie; Hou, Jianhui

    2014-05-20

    As researchers continue to develop new organic materials for solar cells, benzo[1,2-b:4,5-b']dithiophene (BDT)-based polymers have come to the fore. To improve the photovoltaic properties of BDT-based polymers, researchers have developed and applied various strategies leading to the successful molecular design of highly efficient photovoltaic polymers. Novel polymer materials composed of two-dimensional conjugated BDT (2D-conjugated BDT) have boosted the power conversion efficiency of polymer solar cells (PSCs) to levels that exceed 9%. In this Account, we summarize recent progress related to the design and synthesis of 2D-conjugated BDT-based polymers and discuss their applications in highly efficient photovoltaic devices. We introduce the basic considerations for the construction of 2D-conjugated BDT-based polymers and systematic molecular design guidelines. For example, simply modifying an alkoxyl-substituted BDT to form an alkylthienyl-substituted BDT can improve the polymer hole mobilities substantially with little effect on their molecular energy level. Secondly, the addition of a variety of chemical moieties to the polymer can produce a 2D-conjugated BDT unit with more functions. For example, the introduction of a conjugated side chain with electron deficient groups (such as para-alkyl-phenyl, meta-alkoxyl-phenyl, and 2-alkyl-3-fluoro-thienyl) allowed us to modulate the molecular energy levels of 2D-conjugated BDT-based polymers. Through the rational design of BDT analogues such as dithienobenzodithiophene (DTBDT) or the insertion of larger π bridges, we can tune the backbone conformations of these polymers and modulate their photovoltaic properties. We also discuss the influence of 2D-conjugated BDT on polymer morphology and the blends of these polymers with phenyl-C61 (or C71)-butyric acid methyl ester (PCBM). Finally, we summarize the various applications of the 2D-conjugated BDT-based polymers in highly efficient PSC devices. Overall, this Account

  15. Effects of the Substituents of Boron Atoms on Conjugated Polymers Containing B←N Units.

    Science.gov (United States)

    Liu, Jun; Wang, Tao; Dou, Chuandong; Wang, Lixiang

    2018-06-15

    Organoboron chemistry is a new tool to tune the electronic structures and properties of conjugated polymers, which are important for applications in organic opto-electronic devices. To investigate the effects of substituents of boron atoms on conjugated polymers, we synthesized three conjugated polymers based on double B←N bridged bipyridine (BNBP) with various substituents on the boron atoms. By changing the substituents from four phenyl groups and two phenyl groups/two fluorine atoms to four fluorine atoms, the BNBP-based polymers show the blue-shifted absorption spectra, decreased LUMO/HOMO energy levels and enhanced electron affinities, as well as the increased electron mobilities. Moreover, these BNBP-based polymers can be used as electron acceptors for all-polymer solar cells. These results demonstrate that the substituents of boron atoms can effectively modulate the electronic properties and applications of conjugated polymers. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Conjugated polymers developed from alkynes

    Institute of Scientific and Technical Information of China (English)

    Yajing Liu; Jacky W.Y.Lam; Ben Zhong Tang

    2015-01-01

    The numerous merits of conjugated polymers(CPs) have encouraged scientists to develop a variety of synthetic routes to CPs with diverse structures and functionalities. Among the large scope of substrates,alkyne plays an important role in constructing polymers with conjugated backbones. In addition to some well-developed reactions including Glaser–Hay and Sonogashira coupling, azide/thiol-yne click reaction and cyclotrimerization, some novel alkyne-based reactions have also been explored such as oxidative polycoupling, decarbonylative polycoupling and multicomponent tandem polymerizations. his review focuses on the recent progress on the synthetic methodology of CPs in the last ive years using monomers with two or more triple bonds and some of their high-technological applications. Selected examples of materials properties of these CPs are given in this review, such as luorescence response to chemical or physical stimuli, magnetism, white light emission, cell imaging and bioprobing. Finally, a short perspective is raised in regard to the outlook of the preparation methodologies, functionalities as well as potential applications of CPs in the future.

  17. Controlling photophysical properties of ultrasmall conjugated polymer nanoparticles through polymer chain packing

    KAUST Repository

    Piwonski, Hubert Marek

    2017-05-16

    Applications of conjugated polymer nanoparticles (Pdots) for imaging and sensing depend on their size, fluorescence brightness and intraparticle energy transfer. The molecular design of conjugated polymers (CPs) has been the main focus of the development of Pdots. Here we demonstrate that proper control of the physical interactions between the chains is as critical as the molecular design. The unique design of twisted CPs and fine-tuning of the reprecipitation conditions allow us to fabricate ultrasmall (3.0–4.5 nm) Pdots with excellent photostability. Extensive photophysical and structural characterization reveals the essential role played by the packing of the polymer chains in the particles in the intraparticle spatial alignment of the emitting sites, which regulate the fluorescence brightness and the intraparticle energy migration efficiency. Our findings enhance understanding of the relationship between chain interactions and the photophysical properties of CP nanomaterials, providing a framework for designing and fabricating functional Pdots for imaging applications.

  18. Functional Hybrid Biomaterials based on Peptide-Polymer Conjugates for Nanomedicine

    Science.gov (United States)

    Shu, Jessica Yo

    , biological evaluations were performed to investigate the potential of micelles as drug delivery vehicles. In vitro cell studies demonstrated that the micelles can be used as a delivery vehicle to tailor the cellular uptake, time release, and intracellular trafficking of drugs. In vivo biodistribution and pharmacokinetic experiments showed long blood circulation. This work demonstrates that peptide-polymer conjugates can be used as building blocks to generate hierarchical functional nanostructures with a wide range of applications, only one of which is drug delivery.

  19. Conjugated polymer nanoparticles, methods of using, and methods of making

    KAUST Repository

    Habuchi, Satoshi; Piwonski, Hubert Marek; Michinobu, Tsuyoshi

    2017-01-01

    Embodiments of the present disclosure provide for conjugated polymer nanoparticle, method of making conjugated polymer nanoparticles, method of using conjugated polymer nanoparticle, polymers, and the like.

  20. Conjugated polymer nanoparticles, methods of using, and methods of making

    KAUST Repository

    Habuchi, Satoshi

    2017-03-16

    Embodiments of the present disclosure provide for conjugated polymer nanoparticle, method of making conjugated polymer nanoparticles, method of using conjugated polymer nanoparticle, polymers, and the like.

  1. Integrated circuits based on conjugated polymer monolayer.

    Science.gov (United States)

    Li, Mengmeng; Mangalore, Deepthi Kamath; Zhao, Jingbo; Carpenter, Joshua H; Yan, Hongping; Ade, Harald; Yan, He; Müllen, Klaus; Blom, Paul W M; Pisula, Wojciech; de Leeuw, Dago M; Asadi, Kamal

    2018-01-31

    It is still a great challenge to fabricate conjugated polymer monolayer field-effect transistors (PoM-FETs) due to intricate crystallization and film formation of conjugated polymers. Here we demonstrate PoM-FETs based on a single monolayer of a conjugated polymer. The resulting PoM-FETs are highly reproducible and exhibit charge carrier mobilities reaching 3 cm 2  V -1  s -1 . The high performance is attributed to the strong interactions of the polymer chains present already in solution leading to pronounced edge-on packing and well-defined microstructure in the monolayer. The high reproducibility enables the integration of discrete unipolar PoM-FETs into inverters and ring oscillators. Real logic functionality has been demonstrated by constructing a 15-bit code generator in which hundreds of self-assembled PoM-FETs are addressed simultaneously. Our results provide the state-of-the-art example of integrated circuits based on a conjugated polymer monolayer, opening prospective pathways for bottom-up organic electronics.

  2. Conjugated Polymers Atypically Prepared in Water

    Science.gov (United States)

    Invernale, Michael A.; Pendergraph, Samuel A.; Yavuz, Mustafa S.; Ombaba, Matthew; Sotzing, Gregory A.

    2010-01-01

    Processability remains a fundamental issue for the implementation of conducting polymer technology. A simple synthetic route towards processable precursors to conducting polymers (main chain and side chain) was developed using commercially available materials. These soluble precursor systems were converted to conjugated polymers electrochemically in aqueous media, offering a cheaper and greener method of processing. Oxidative conversion in aqueous and organic media each produced equivalent electrochromics. The precursor method enhances the yield of the electrochromic polymer obtained over that of electrodeposition, and it relies on a less corruptible electrolyte bath. However, electrochemical conversion of the precursor polymers often relies on organic salts and solvents. The ability to achieve oxidative conversion in brine offers a less costly and a more environmentally friendly processing step. It is also beneficial for biological applications. The electrochromics obtained herein were evaluated for electronic, spectral, and morphological properties. PMID:20959869

  3. Recent Advances in Conjugated Polymers for Light Emitting Devices

    Science.gov (United States)

    AlSalhi, Mohamad Saleh; Alam, Javed; Dass, Lawrence Arockiasamy; Raja, Mohan

    2011-01-01

    A recent advance in the field of light emitting polymers has been the discovery of electroluminescent conjugated polymers, that is, kind of fluorescent polymers that emit light when excited by the flow of an electric current. These new generation fluorescent materials may now challenge the domination by inorganic semiconductor materials of the commercial market in light-emitting devices such as light-emitting diodes (LED) and polymer laser devices. This review provides information on unique properties of conjugated polymers and how they have been optimized to generate these properties. The review is organized in three sections focusing on the major advances in light emitting materials, recent literature survey and understanding the desirable properties as well as modern solid state lighting and displays. Recently, developed conjugated polymers are also functioning as roll-up displays for computers and mobile phones, flexible solar panels for power portable equipment as well as organic light emitting diodes in displays, in which television screens, luminous traffic, information signs, and light-emitting wallpaper in homes are also expected to broaden the use of conjugated polymers as light emitting polymers. The purpose of this review paper is to examine conjugated polymers in light emitting diodes (LEDs) in addition to organic solid state laser. Furthermore, since conjugated polymers have been approved as light-emitting organic materials similar to inorganic semiconductors, it is clear to motivate these organic light-emitting devices (OLEDs) and organic lasers for modern lighting in terms of energy saving ability. In addition, future aspects of conjugated polymers in LEDs were also highlighted in this review. PMID:21673938

  4. Photoinduced partial charge transfer between conjugated polymer and fullerene in solutions

    International Nuclear Information System (INIS)

    Lin Hongzhen; Weng Yufeng; Huang Hongmin; He Qingguo; Zheng Min; Bai Fenglian

    2004-01-01

    Photoinduced charge transfer between a conjugated polymer and C 60 and the related processes were investigated in dilute solutions. The substantial fluorescence quenching is correlated with the efficient exciton diffusion within the polymer chains, according to which a sphere-of-action mechanism is proposed. An emissive exciplex was found formed between the conjugated polymer and fullerene in a nonpolar solvent, indicating the occurrence of a photoinduced partial charge transfer process. The low-energy sites in the polymer are believed to play a crucial role in the partial charge transfer. The asymmetry of the exciplex provides a method for evaluating the tendency of photoinduced charge separation between the donor and the acceptor. This method allows screening candidates for photovoltaic applications

  5. Femtosecond Pump-Push-Probe and Pump-Dump-Probe Spectroscopy of Conjugated Polymers: New Insight and Opportunities.

    Science.gov (United States)

    Kee, Tak W

    2014-09-18

    Conjugated polymers are an important class of soft materials that exhibit a wide range of applications. The excited states of conjugated polymers, often referred to as excitons, can either deactivate to yield the ground state or dissociate in the presence of an electron acceptor to form charge carriers. These interesting properties give rise to their luminescence and the photovoltaic effect. Femtosecond spectroscopy is a crucial tool for studying conjugated polymers. Recently, more elaborate experimental configurations utilizing three optical pulses, namely, pump-push-probe and pump-dump-probe, have been employed to investigate the properties of excitons and charge-transfer states of conjugated polymers. These studies have revealed new insight into femtosecond torsional relaxation and detrapping of bound charge pairs of conjugated polymers. This Perspective highlights (1) the recent achievements by several research groups in using pump-push-probe and pump-dump-probe spectroscopy to study conjugated polymers and (2) future opportunities and potential challenges of these techniques.

  6. Polymer-Block-Polypeptides and Polymer-Conjugated Hybrid Materials as Stimuli-Responsive Nanocarriers for Biomedical Applications.

    Science.gov (United States)

    John, Johnson V; Johnson, Renjith P; Heo, Min Seon; Moon, Byeong Kyu; Byeon, Seong Jin; Kim, Il

    2015-01-01

    Stimuli-responsive nanocarriers are a class of soft materials that includes natural polymers, synthetic polymers, and polypeptides. Recently, modern synthesis tools such as atom transfer radical polymerization, reversible addition-fragmentation chain transfer polymerization, nitroxide-mediated radical polymerization, ring-opening polymerization of α-amino acid N-carboxyanhydrides, and various "click" chemistry strategies were simultaneously employed for the design and synthesis of nanosized drug delivery vehicles. Importantly, the research focused on the improvement of the nanocarrier targetability and the site-specific, triggered release of therapeutics with high drug loading efficiency and minimal drug leakage during the delivery to specific targets. In this context, nanocarriers responsive to common stimuli such as pH, temperature, redox potential, light, etc. have been widely used for the controlled delivery of therapeutics to pathological sites. Currently, different synthesis and self-assembly strategies improved the drug loading efficacy and targeted delivery of therapeutic agents to the desired site. In particular, polypeptide-containing hybrid materials have been developed for the controlled delivery of therapeutic agents. Therefore, stimuli-sensitive synthetic polypeptide-based materials have been extensively investigated in recent years. This review focuses on recent advances in the development of polymer-block-polypeptides and polymer-conjugated hybrid materials that have been designed and evaluated for various stimuli-responsive drug and gene delivery applications.

  7. Bis-polymer lipid-peptide conjugates and nanoparticles thereof

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Ting; Dong, He; Shu, Jessica; Dube, Nikhil

    2018-04-24

    The present invention provides bis-polymer lipid-peptide conjugates containing a hydrophobic block and headgroup containing a helical peptide and two polymer blocks. The conjugates can self-assemble to form helix bundle subunits, which in turn assemble to provide micellar nanocarriers for drug cargos and other agents. Particles containing the conjugates and methods for forming the particles are also disclosed.

  8. Electrochromic in conjugated polymers

    International Nuclear Information System (INIS)

    Picado Valenzuela, Alfredo

    2007-01-01

    This revision considered object the description of one of the materials with the greatest potential in the field of electrochromic (mainly in the visible region): the conjugated polymers (CP), area of enormous potential both now and in a short time ahead. The CP are insulating materials and organic semiconductors in a state not doped. They can be doped positively or negatively being observed a significant increase in the conductivity and being generated a color change in these materials. The understanding of how optical properties vary based on the chemical structure of the polymer or its mixtures and more precisely of the alternatives that can be entered into the conjugated system or π system to obtain a material that besides to be flexible, environmentally stable, presents the colored states. The revision was centred chiefly in the polypyrrole (Ppy), the polythiophene (PTh) and their derivatives such as poly (3.4-ethylenedioxythiophene) (PEDOT). The advantage of using monomers with variable structure, to adjust the composition of the copolymer, or to blend with the PC, allows to obtain a variety of colored states that can be modulated through the visible spectrum and even with applications to wavelengths outside of this region. Because the PC presented at least two different colored states can be varied continuously as a function of the voltage applied. In some cases, they may submit multicoloured statements, which offers a range of possibilities for their application in flexible electronic devices type screens and windows. Applications include smart windows, camouflage clothing and data screens. This type of material is emerging as one of the substitutes of the traditional inorganic semiconductor, with the advantage of its low cost, high flexibility and the possibility to generate multiple colors through the handling of the monomers in the structure and control of energy of his band gap. (author) [es

  9. Lipid-peptide-polymer conjugates and nanoparticles thereof

    Science.gov (United States)

    Xu, Ting; Dong, He; Shu, Jessica

    2015-06-02

    The present invention provides a conjugate having a peptide with from about 10 to about 100 amino acids, wherein the peptide adopts a helical structure. The conjugate also includes a first polymer covalently linked to the peptide, and a hydrophobic moiety covalently linked to the N-terminus of the peptide, wherein the hydrophobic moiety comprises a second polymer or a lipid moiety. The present invention also provides helix bundles form by self-assembling the conjugates, and particles formed by self-assembling the helix bundles. Methods of preparing the helix bundles and particles are also provided.

  10. Effect of backbone structure on charge transport along isolated conjugated polymer chains

    International Nuclear Information System (INIS)

    Siebbeles, Laurens D.A.; Grozema, Ferdinand C.; Haas, Matthijs P. de; Warman, John M.

    2005-01-01

    Fast charge transport in conjugated polymers is essential for their application in opto-electronic devices. In the present paper, measurements and theoretical modeling of the mobility of excess charges along isolated chains of conjugated polymers in dilute solution are presented. Charge carriers were produced by irradiation of the polymer solution with 3-MeV electrons from a Van de Graaff accelerator. The mobilities of the charges along the polymer chains were obtained from time-resolved microwave conductivity measurements. The mobilities are strongly dependent on the chemical nature of the polymer backbone. Comparison of the experimental data with results from ab initio quantum mechanical calculations shows that the measured mobilities are strongly limited by torsional disorder, chemical defects and chain ends. Improvement of the structure of polymer backbones is therefore expected to significantly enhance the performance of these materials in 'plastic electronics'

  11. Thiolated polymers: synthesis and in vitro evaluation of polymer-cysteamine conjugates.

    Science.gov (United States)

    Bernkop-Schnürch, A; Clausen, A E; Hnatyszyn, M

    2001-09-11

    The purpose of the present study was to synthesize and characterize novel thiolated polymers. Mediated by a carbodiimide cysteamine was covalently linked to sodium carboxymethylcellulose (CMC) and polycarbophil (PCP). The resulting CMC-cysteamine conjugates displayed 77.9+/-6.7 and 365.1+/-8.7 micromol thiol groups per gram of polymer, whereas the PCP-cysteamine conjugates showed 26.3+/-1.9 and 122.7+/-3.8 micromol thiol groups per gram of polymer (mean+/-S.D.; n=3). In aqueous solutions above pH 5.0 both modified polymers were capable of forming inter- and/or intra-molecular disulfide bonds. The reaction velocity of this oxidation process was accelerated with a decrease in the proton concentration. The oxidation proceeded more rapidly within thiolated CMC than within thiolated PCP. Permeation studies carried out in Ussing-type chambers with freshly excised intestinal mucosa from guinea pigs utilizing sodium fluorescein as model drug for the paracellular uptake revealed an enhancement ratio (R=P(app) (conjugate)/P(app) (control)) of 1.15 and 1.41 (mean+/-S.D.; n=3) for the higher thiolated CMC-cysteamine (0.5%; m/v) and PCP-cysteamine conjugate (1.0%; m/v), respectively. The decrease in the transepithelial electrical resistance values was in good correlation with the enhancement ratios. Due to a high crosslinking tendency by the formation of disulfide bonds stabilizing drug carrier systems based on thiolated polymers and a permeation enhancing effect, CMC- and PCP-cysteamine conjugates represent promising excipients for the development of novel drug delivery systems.

  12. Hierarchical assembly of branched supramolecular polymers from (cyclic Peptide)-polymer conjugates.

    Science.gov (United States)

    Koh, Ming Liang; Jolliffe, Katrina A; Perrier, Sébastien

    2014-11-10

    We report the synthesis and assembly of (N-methylated cyclic peptide)-polymer conjugates for which the cyclic peptide is attached to either the α- or both α- and ω- end groups of a polymer. A combination of chromatographic, spectroscopic, and scattering techniques reveals that the assembly of the conjugates follows a two-level hierarchy, initially driven by H-bond formation between two N-methylated cyclic peptides, followed by unspecific, noncovalent aggregation of this peptide into small domains that behave as branching points and lead to the formation of branched supramolecular polymers.

  13. Side Chain Engineering in Solution-Processable Conjugated Polymers

    KAUST Repository

    Mei, Jianguo

    2014-01-14

    Side chains in conjugated polymers have been primarily utilized as solubilizing groups. However, these side chains have roles that are far beyond. We advocate using side chain engineering to tune a polymer\\'s physical properties, including absorption, emission, energy level, molecular packing, and charge transport. To date, numerous flexible substituents suitable for constructing side chains have been reported. In this Perspective article, we advocate that the side chain engineering approach can advance better designs for next-generation conjugated polymers. © 2013 American Chemical Society.

  14. Conjugated Polymers for Energy Production

    DEFF Research Database (Denmark)

    Livi, Francesco

    This dissertation is aimed at developing materials for flexible, large area, ITO-free polymer solar cells (PSCs) fully printed under ambient conditions. A large screening of conjugated polymers, both novel and well-known materials, has been carried out in order to find suitable candidates...... polymerization method for industrial production of polymers. Several DArP protocols have been employed for the synthesis of PPDTBT leading to polymers with high structural regularity and photovoltaic performances comparable with the same materials synthesized via Stille cross-coupling polymerization...

  15. Subgap Absorption in Conjugated Polymers

    Science.gov (United States)

    Sinclair, M.; Seager, C. H.; McBranch, D.; Heeger, A. J; Baker, G. L.

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination.

  16. Degradable conjugated polymers for the selective sorting of semiconducting carbon nanotubes

    Science.gov (United States)

    Gopalan, Padma; Arnold, Michael Scott; Kansiusarulsamy, Catherine Kanimozhi; Brady, Gerald Joseph; Shea, Matthew John

    2018-04-10

    Conjugated polymers composed of bi-pyridine units linked to 9,9-dialkyl fluorenyl-2,7-diyl units via imine linkages along the polymer backbone are provided. Also provided are semiconducting single-walled carbon nanotubes coated with the conjugated polymers and methods of sorting and separating s-SWCNTs from a sample comprising a mixture of s-SWCNTs and metallic single-walled carbon nanotubes using the conjugated polymers.

  17. Hemoglobin Detection on a Microfluidic Sensor Chip with a Partially Conjugated Polymer

    International Nuclear Information System (INIS)

    Eo, Soo Han; Won, Kwang Jae; Song, Simon; Yoon, Bora; Kim, Jong Man

    2010-01-01

    The development of efficient chemosensors based on the conjugated polymers has been the central focus of a large number of recent research programs. The presence of extensively delocalized electrons and conformational restrictions of the backbone structures make conjugated polymers attractive sensory materials. In these polymers, molecular recognition events influence electronic absorption and emission properties. Thus, a wide variety of conjugated polymer-based sensors have been investigated. However, the majority of the conjugated polymer sensors described to date have been explored in the form of solutions or thin films. Most biologically interesting target molecules, such as proteins, carbohydrates, nucleic acids, or ions, are only soluble in water. Thus, it is desirable to use water-soluble conjugated polymers as sensor matrices. In general, in order to make water-soluble conjugated polymers tedious procedures are required since most synthetic methods developed for this purpose are incompatible with sidechain functionalities. Accordingly, protecting group strategies are required to prepare polymers with requisite functional groups that foster water solubility

  18. Conjugated Polymers as Actuators: Modes of Actuation

    DEFF Research Database (Denmark)

    Skaarup, Steen

    2004-01-01

    The physical and chemical properties of conjugated polymers often depend very strongly on the degree of doping with anions or cations. The movement of ions in and out of the polymer matrix as it is redox cycled is also accompanied by mechanical changes. Both the volume and the stiffness can exhibit...... significant differences between the oxidized and reduced states. These effects form the basis of the use of conjugated polymers as actuators (or “artificial muscles”) controllable by a small (1-10 V) voltage. Three basic modes of actuation (bending, linear extension and stiffness change) have been proposed...

  19. Conjugated polymers as actuators: modes of actuation

    DEFF Research Database (Denmark)

    Skaarup, Steen

    2007-01-01

    The physical and chemical properties of conjugated polymers often depend very strongly on the degree of doping with anions or cations. The movement of ions in and out of the polymer matrix as it is redox cycled is also accompanied by mechanical changes. Both the volume and the stiffness can exhibit...... significant differences between the oxidized and reduced states. These effects form the basis of the use of conjugated polymers as actuators (or “artificial muscles”) controllable by a small (1-10 V) voltage. Three basic modes of actuation (bending, linear extension and stiffness change) have been proposed...

  20. Conjugated Polymer with Intrinsic Alkyne Units for Synergistically Enhanced Raman Imaging in Living Cells.

    Science.gov (United States)

    Li, Shengliang; Chen, Tao; Wang, Yunxia; Liu, Libing; Lv, Fengting; Li, Zhiliang; Huang, Yanyi; Schanze, Kirk S; Wang, Shu

    2017-10-16

    Development of Raman-active materials with enhanced and distinctive Raman vibrations in the Raman-silent region (1800-2800 cm -1 ) is highly required for specific molecular imaging of living cells with high spatial resolution. Herein, water-soluble cationic conjugated polymers (CCPs), poly(phenylene ethynylene) (PPE) derivatives, are explored for use as alkyne-state-dependent Raman probes for living cell imaging due to synergetic enhancement effect of alkyne vibrations in Raman-silent region compared to alkyne-containing small molecules. The enhanced alkyne signals result from the integration of alkyne groups into the rigid backbone and the delocalized π-conjugated structure. PPE-based conjugated polymer nanoparticles (CPNs) were also prepared as Raman-responsive nanomaterials for distinct imaging application. This work opens a new way into the development of conjugated polymer materials for enhanced Raman imaging. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Molecular Orientation of Conjugated Polymer Chains in Nanostructures and Thin Films: Review of Processes and Application to Optoelectronics

    Directory of Open Access Journals (Sweden)

    Varun Vohra

    2017-01-01

    Full Text Available Semiconducting polymers are composed of elongated conjugated polymer backbones and side chains with high solubility and mechanical properties. The combination of these two features results in a high processability and a potential to orient the conjugated backbones in thin films and nanofibers. The thin films and nanofibers are usually composed of highly crystalline (high charge transport and amorphous parts. Orientation of conjugated polymer can result in enhanced charge transport or optical properties as it induces increased crystallinity or preferential orientation of the crystallites. After summarizing the potential strategies to exploit molecular order in conjugated polymer based optoelectronic devices, we will review some of the fabrication processes to induce molecular orientation. In particular, we will review the cases involving molecular and interfacial interactions, unidirectional deposition processes, electrospinning, and postdeposition mechanical treatments. The studies presented here clearly demonstrate that process-controlled molecular orientation of the conjugated polymer chains can result in high device performances (mobilities over 40 cm2·V−1·s−1 and solar cells with efficiencies over 10%. Furthermore, the peculiar interactions between molecularly oriented polymers and polarized light have the potential not only to generate low-cost and low energy consumption polarized light sources but also to fabricate innovative devices such as solar cell integrated LCDs or bipolarized LEDs.

  2. Dual-Color Fluorescence Imaging of Magnetic Nanoparticles in Live Cancer Cells Using Conjugated Polymer Probes

    Science.gov (United States)

    Sun, Minjie; Sun, Bin; Liu, Yun; Shen, Qun-Dong; Jiang, Shaojun

    2016-01-01

    Rapid growth in biological applications of nanomaterials brings about pressing needs for exploring nanomaterial-cell interactions. Cationic blue-emissive and anionic green-emissive conjugated polymers are applied as dual-color fluorescence probes to the surface of negatively charged magnetic nanoparticles through sequentially electrostatic adsorption. These conjugated polymers have large extinction coefficients and high fluorescence quantum yield (82% for PFN and 62% for ThPFS). Thereby, one can visualize trace amount (2.7 μg/mL) of fluorescence-labeled nanoparticles within cancer cells by confocal laser scanning microscopy. Fluorescence labeling by the conjugated polymers is also validated for quantitative determination of the internalized nanoparticles in each individual cell by flow cytometry analysis. Extensive overlap of blue and green fluorescence signals in the cytoplasm indicates that both conjugated polymer probes tightly bind to the surface of the nanoparticles during cellular internalization. The highly charged and fluorescence-labeled nanoparticles non-specifically bind to the cell membranes, followed by cellular uptake through endocytosis. The nanoparticles form aggregates inside endosomes, which yields a punctuated staining pattern. Cellular internalization of the nanoparticles is dependent on the dosage and time. Uptake efficiency can be enhanced three-fold by application of an external magnetic field. The nanoparticles are low cytotoxicity and suitable for simultaneously noninvasive fluorescence and magnetic resonance imaging application. PMID:26931282

  3. Subgap absorption in conjugated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Sinclair, M.; Seager, C.H. (Sandia National Labs., Albuquerque, NM (USA)); McBranch, D.; Heeger, A.J. (California Univ., Santa Barbara, CA (USA)); Baker, G.L. (Bell Communications Research, Inc., Red Bank, NJ (USA))

    1991-01-01

    Along with X{sup (3)}, the magnitude of the optical absorption in the transparent window below the principal absorption edge is an important parameter which will ultimately determine the utility of conjugated polymers in active integrated optical devices. With an absorptance sensitivity of < 10{sup {minus}5}, Photothermal Deflection Spectroscopy (PDS) is ideal for determining the absorption coefficients of thin films of transparent'' materials. We have used PDS to measure the optical absorption spectra of the conjugated polymers poly(1,4-phenylene-vinylene) (and derivitives) and polydiacetylene-4BCMU in the spectral region from 0.55 eV to 3 eV. Our spectra show that the shape of the absorption edge varies considerably from polymer to polymer, with polydiacetylene-4BCMU having the steepest absorption edge. The minimum absorption coefficients measured varied somewhat with sample age and quality, but were typically in the range 1 cm{sup {minus}1} to 10 cm{sup {minus}1}. In the region below 1 eV, overtones of C-H stretching modes were observed, indicating that further improvements in transparency in this spectral region might be achieved via deuteration of fluorination. 11 refs., 4 figs.

  4. Dye linked conjugated homopolymers: using conjugated polymer electroluminescence to optically pump porphyrin-dye emission

    DEFF Research Database (Denmark)

    Nielsen, K.T.; Spanggaard, H.; Krebs, Frederik C

    2004-01-01

    . Electroluminescent devices of the homopolymer itself and of the zinc-porphyrin containing polymer were prepared and the nature of the electroluminescence was characterized. The homopolymer segments were found to optically pump the emission of the zinc-porphyrin dye moities. The homopolymer exhibits blue......Zinc-porphyrin dye molecules were incorporated into the backbone of a conjugated polymer material by a method, which allowed for the incorporation of only one zinc-porphyrin dye molecule into the backbone of each conjugated polymer molecule. The electronic properties of the homopolymer were...

  5. A Triphenylamine-Based Conjugated Polymer with Donor-π-Acceptor Architecture as Organic Sensitizer for Dye-Sensitized Solar Cells.

    Science.gov (United States)

    Zhang, Wei; Fang, Zhen; Su, Mingjuan; Saeys, Mark; Liu, Bin

    2009-09-17

    A conjugated polymer containing an electron donating backbone (triphenylamine) and an electron accepting side chain (cyanoacetic acid) with conjugated thiophene units as the linkers has been synthesized. Dye-sensitized solar cells (DSSCs) are fabricated utilizing this material as the dye sensitizer, resulting a typical power conversion efficiency of 3.39% under AM 1.5 G illumination, which represents the highest efficiency for polymer dye-sensitized DSSCs reported so far. The results show the good promise of conjugated polymers as sensitizers for DSSC applications. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Excitons in conjugated polymers: Do we need a paradigma change?

    Energy Technology Data Exchange (ETDEWEB)

    Beenken, Wichard J.D. [Department of Theoretical Physics I, Ilmenau University of Thechnology (Germany)

    2009-12-15

    We have previously shown that both, polymer conformation and dynamics are crucial for the exciton transport in conjugated polymers. Thereby we found that the usual Foerster-type hopping transfer model - even if one applies the line-dipole approximation - falls short in one crucial aspect: the nature of the sites the excitons are transferred between is still unclear. We found that the simple model of spectroscopic units defined as segments of the polymer chains separated by structural defects breaking the {pi}-conjugation is only justified for chemical defects like hydrogenated double bonds, or extreme gauche (90 ) torsions between the monomers. Both defects are far too rare in a well-prepared conjugated polymer to explain the mean spectroscopic-unit length of typically 6-7 monomers. Meanwhile, also the concept of dynamical formation of the spectroscopic units, we had previously suggested, has also failed. Thus the question of a paradigma change concerning the exciton transport in conjugated polymers appears on the agenda. (Abstract Copyright [2009], Wiley Periodicals, Inc.)

  7. Conjugated polymer photovoltaic devices and materials

    International Nuclear Information System (INIS)

    Mozer, A.J.; Niyazi, Serdar Sariciftci

    2006-01-01

    The science and technology of conjugated polymer-based photovoltaic devices (bulk heterojunction solar cells) is highlighted focusing on three major issues, i.e. (i) nano-morphology optimization, (ii) improving charge carrier mobility, (iii) improving spectral sensitivity. Successful strategies towards improved photovoltaic performance are presented using various novel materials, including double-cable polymers, regioregular polymers and low bandgap polymers. The examples presented herein demonstrate that the bulk heterojunction concept is a viable approach towards developing photovoltaic systems by inexpensive solution-based fabrication technologies. (authors)

  8. Polarized Emission from Conjugated Polymer Chains Aligned by Epitaxial Growth during Off-Center Spin-Coating

    Directory of Open Access Journals (Sweden)

    Takuya Anzai

    2017-01-01

    Full Text Available Due to their macromolecular nature, conjugated polymers can be relatively easily aligned by applying a variety of processes resulting in either elongation or ordering of their conjugated backbones. Processes that induce chain alignment include electrospinning, mechanical rubbing, epitaxial growth, and nanoconfinement and unidirectional deposition techniques such as off-center spin-coating. In this study, we compare these deposition techniques by applying them to a green-emitting conjugated polymer material that exhibits liquid crystalline phase behavior. Our study reveals that while methods such as electrospinning and mechanical rubbing can be useful to locally generate polymer chain alignment, the combination of epitaxial growth using 1,3,5-trichlorobenzene as crystallizing agent with off-center spin-coating results in the formation of anisotropic nanofiber-like structures with enhanced crystallinity degree and polarized light-emission properties. The unidirectional epitaxial growth was also applied to a red-emitting polymer that exhibits polarization ratios up to 4.1. Our results emphasize that this simple solution formulation and process can be used for the fabrication of polarized thin films of a variety of conjugated polymers with potential applications in the advanced display technologies or analytical equipment fields.

  9. Water Soluble Polymers for Pharmaceutical Applications

    Directory of Open Access Journals (Sweden)

    Veeran Gowda Kadajji

    2011-11-01

    Full Text Available Advances in polymer science have led to the development of novel drug delivery systems. Some polymers are obtained from natural resources and then chemically modified for various applications, while others are chemically synthesized and used. A large number of natural and synthetic polymers are available. In the present paper, only water soluble polymers are described. They have been explained in two categories (1 synthetic and (2 natural. Drug polymer conjugates, block copolymers, hydrogels and other water soluble drug polymer complexes have also been explained. The general properties and applications of different water soluble polymers in the formulation of different dosage forms, novel delivery systems and biomedical applications will be discussed.

  10. Preparation of conjugated polymer suspensions by using ultrasonic atomizer

    Energy Technology Data Exchange (ETDEWEB)

    Tada, Kazuya, E-mail: tada@eng.u-hyogo.ac.jp; Onoda, Mitsuyoshi

    2010-11-30

    The electrophoretic deposition is a method useful to prepare conjugated polymer films for electronic devices. This method provides high material recovery rate on the substrate from the suspension, in contrast to the conventional spin-coating in which most of the material placed on the substrate is blown away. Although manual reprecipitation technique successfully yields suspensions of various conjugated polymers including polyfluorene derivatives, it is favorable to control the preparation process of suspensions. In this context, this paper reports preliminary results on the preparation of suspension of conjugated polymer by using an ultrasonic atomizer. While the resultant films do not show particular difference due to the preparation methods of the suspension, the electric current profiles during the electrophoretic deposition suggests that the ultrasonic atomization of polymer solution prior to be mixed with poor solvent results in smaller and less uniform colloidal particles than the conventional manual pouring method.

  11. Water Soluble Polymers for Pharmaceutical Applications

    OpenAIRE

    Veeran Gowda Kadajji; Guru V. Betageri

    2011-01-01

    Advances in polymer science have led to the development of novel drug delivery systems. Some polymers are obtained from natural resources and then chemically modified for various applications, while others are chemically synthesized and used. A large number of natural and synthetic polymers are available. In the present paper, only water soluble polymers are described. They have been explained in two categories (1) synthetic and (2) natural. Drug polymer conjugates, block copolymers, hydrogel...

  12. Preparation and characterization of conjugated polymers made by postpolymerization reactions of alternating polyketones.

    Science.gov (United States)

    Cheng, Chen; Guironnet, Damien; Barborak, James; Brookhart, Maurice

    2011-06-29

    Conjugated polymers possessing a poly(2,5-dimethylene-2,5-dihydrofuran) backbone were prepared through postpolymerization reaction of styrenic polyketones with bromine in one-pot reactions. The modification is proposed to proceed via condensation of two repeating units to form a fully characterized polymer with a poly(2,5-dimethylenetetrahydrofuran) backbone. Subsequent bromination and elimination of HBr yield a polymer with a fully conjugated carbon backbone. The new conjugated polymers were characterized by NMR, IR, and UV-vis spectroscopies and by CV. These polymers have strong absorption in the visible region, with the absorption peaks shifted to the NIR region upon doping with acids. The ease of the synthesis of the starting polyketone and of the modifications allows large-scale preparation of those conjugated polymers.

  13. Synthesis of regioregular pentacene-containing conjugated polymers

    KAUST Repository

    Okamoto, Toshihiro; Jiang, Ying; Becerril, Hector A.; Hong, Sanghyun; Senatore, Michelle L.; Tang, Ming L.; Toney, Michael F.; Siegrist, Theo; Bao, Zhenan

    2011-01-01

    We report the synthesis and characterization of a new class of regioregular pentacene-containing conjugated polymers via our synthetic routes reported previously. We found that our regioregular pentacene polymers showed improved ordering than their regiorandom counterpart as well as ambipolar OFET performance. © 2011 The Royal Society of Chemistry.

  14. Side Chain Engineering in Solution-Processable Conjugated Polymers

    KAUST Repository

    Mei, Jianguo; Bao, Zhenan

    2014-01-01

    Side chains in conjugated polymers have been primarily utilized as solubilizing groups. However, these side chains have roles that are far beyond. We advocate using side chain engineering to tune a polymer's physical properties, including absorption

  15. Syntheses and optical properties of triphenylene-containing conjugated polymers

    International Nuclear Information System (INIS)

    Chou, C.-E.; Wang Degang; Bagui, Mahuya; Hsu, Jeffrey; Chakraborty, Sanjiban; Peng Zhonghua

    2010-01-01

    In this paper, we report the detailed synthesis and optical properties of three new conjugated polymers containing triphenylene units in the backbone. Polymer PTPT exhibits strong folding propensity and forms foldamers in both polar and nonpolar solvents. PTPA, with two long alkyl chains attached to the bridging phenyl ring, exhibits mainly as interchain aggregates in 'poor' solvents (DMSO and acetonitrile), but adopts a folding conformation in solvent mixtures with a high poor solvent content. PTPV, on the other hand, adopts a random nonfolding conformation in both polar and nonpolar solvents. The low folding propensity of PTPV is likely due to the added geometrical flexibility of the vinyl bonds. Among the three polymers, PTPV is most fluorescent with a fluorescence quantum yield as high as 0.87, suggesting its potential applications as light-emitting materials or fluorescence-based sensors. PTPT, on the other hand, with its strong folding property, may find applications as efficient charge-transporting materials.

  16. Quantum dot-polymer conjugates for stable luminescent displays.

    Science.gov (United States)

    Ghimire, Sushant; Sivadas, Anjaly; Yuyama, Ken-Ichi; Takano, Yuta; Francis, Raju; Biju, Vasudevanpillai

    2018-05-23

    The broad absorption of light in the UV-Vis-NIR region and the size-based tunable photoluminescence color of semiconductor quantum dots make these tiny crystals one of the most attractive antennae in solar cells and phosphors in electrooptical devices. One of the primary requirements for such real-world applications of quantum dots is their stable and uniform distribution in optically transparent matrices. In this work, we prepare transparent thin films of polymer-quantum dot conjugates, where CdSe/ZnS quantum dots are uniformly distributed at high densities in a chitosan-polystyrene copolymer (CS-g-PS) matrix. Here, quantum dots in an aqueous solution are conjugated to the copolymer by a phase transfer reaction. With the stable conjugation of quantum dots to the copolymer, we prevent undesired phase separation between the two and aggregation of quantum dots. Furthermore, the conjugate allows us to prepare transparent thin films in which quantum dots are uniformly distributed at high densities. The CS-g-PS copolymer helps us in not only preserving the photoluminescence properties of quantum dots in the film but also rendering excellent photostability to quantum dots at the ensemble and single particle levels, making the conjugate a promising material for photoluminescence-based devices.

  17. Particle-in-a-box model of one-dimensional excitons in conjugated polymers

    Science.gov (United States)

    Pedersen, Thomas G.; Johansen, Per M.; Pedersen, Henrik C.

    2000-04-01

    A simple two-particle model of excitons in conjugated polymers is proposed as an alternative to usual highly computationally demanding quantum chemical methods. In the two-particle model, the exciton is described as an electron-hole pair interacting via Coulomb forces and confined to the polymer backbone by rigid walls. Furthermore, by integrating out the transverse part, the two-particle equation is reduced to one-dimensional form. It is demonstrated how essentially exact solutions are obtained in the cases of short and long conjugation length, respectively. From a linear combination of these cases an approximate solution for the general case is obtained. As an application of the model the influence of a static electric field on the electron-hole overlap integral and exciton energy is considered.

  18. 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

  19. Two-dimensional charge transport in self-organized, high-mobility conjugated polymers

    DEFF Research Database (Denmark)

    Sirringhaus, H.; Brown, P.J.; Friend, R.H.

    1999-01-01

    Self-organization in many solution-processed, semiconducting conjugated polymers results in complex microstructures, in which ordered microcrystalline domains are embedded in an amorphous matrix(I). This has important consequences for electrical properties of these materials: charge transport...... of the ordered microcrystalline domains in the conjugated polymer poly(3-hexylthiophene), P3HT, Self-organization in P3HT results in a lamella structure with two-dimensional conjugated sheets formed by interchain stacking. We find that, depending on processing conditions, the lamellae can adopt two different...... of polymer transistors in logic circuits(5) and active-matrix displays(4,6)....

  20. Substituted Polyacetylenes Prepared with Rh Catalysts: From Linear to Network-Type Conjugated Polymers

    Czech Academy of Sciences Publication Activity Database

    Sedláček, J.; Balcar, Hynek

    2017-01-01

    Roč. 57, č. 1 (2017), s. 31-51 ISSN 1558-3724 Institutional support: RVO:61388955 Keywords : conjugated polymers * polyacetylenes * conjugated polymer networks Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Polymer science Impact factor: 6.459, year: 2016

  1. 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

  2. π-Conjugated polymer anisotropic organogel nanofibrous assemblies for thermoresponsive photonic switches.

    Science.gov (United States)

    Narasimha, Karnati; Jayakannan, Manickam

    2014-11-12

    The present work demonstrates one of the first examples of π-conjugated photonic switches (or photonic wave plates) based on the tailor-made π-conjugated polymer anisotropic organogel. New semicrystalline segmented π-conjugated polymers are designed with rigid aromatic oligophenylenevinylene π-core and flexible alkyl chain along the polymer backbone. These polymers are found to be self-assembled as semicrystalline or amorphous with respect to the number of carbon atoms in the alkyl units. These semicrystalline polymers produce organogels having nanofibrous morphology of 20 nm thickness with length up to 5 μm. The polymer organogel is aligned in a narrow glass capillary, and this anisotropic gel device is further demonstrated as photonic switches. The glass capillary device behaves as typical λ/4 photonic wave plates upon the illumination of the plane polarized light. The λ/4 photonic switching ability is found to be maximum at θ = 45° angle under the cross polarizers. The orthogonal arrangements of the gel capillaries produce dark and bright spots as on-and-off optical switches. Thermoreversibility of the polymer organogel (also its xerogel) was exploited to construct thermoresponsive photonic switches for the temperature window starting from 25 to 160 °C. The organic photonic switch concept can be adapted to large number of other π-conjugated materials for optical communication and storage.

  3. Peptide/protein-polymer conjugates: synthetic strategies and design concepts.

    Science.gov (United States)

    Gauthier, Marc A; Klok, Harm-Anton

    2008-06-21

    This feature article provides a compilation of tools available for preparing well-defined peptide/protein-polymer conjugates, which are defined as hybrid constructs combining (i) a defined number of peptide/protein segments with uniform chain lengths and defined monomer sequences (primary structure) with (ii) a defined number of synthetic polymer chains. The first section describes methods for post-translational, or direct, introduction of chemoselective handles onto natural or synthetic peptides/proteins. Addressed topics include the residue- and/or site-specific modification of peptides/proteins at Arg, Asp, Cys, Gln, Glu, Gly, His, Lys, Met, Phe, Ser, Thr, Trp, Tyr and Val residues and methods for producing peptides/proteins containing non-canonical amino acids by peptide synthesis and protein engineering. In the second section, methods for introducing chemoselective groups onto the side-chain or chain-end of synthetic polymers produced by radical, anionic, cationic, metathesis and ring-opening polymerization are described. The final section discusses convergent and divergent strategies for covalently assembling polymers and peptides/proteins. An overview of the use of chemoselective reactions such as Heck, Sonogashira and Suzuki coupling, Diels-Alder cycloaddition, Click chemistry, Staudinger ligation, Michael's addition, reductive alkylation and oxime/hydrazone chemistry for the convergent synthesis of peptide/protein-polymer conjugates is given. Divergent approaches for preparing peptide/protein-polymer conjugates which are discussed include peptide synthesis from synthetic polymer supports, polymerization from peptide/protein macroinitiators or chain transfer agents and the polymerization of peptide side-chain monomers.

  4. Non-Fullerene Polymer Solar Cells Based on Alkylthio and Fluorine Substituted 2D-Conjugated Polymers Reach 9.5% Efficiency.

    Science.gov (United States)

    Bin, Haijun; Zhang, Zhi-Guo; Gao, Liang; Chen, Shanshan; Zhong, Lian; Xue, Lingwei; Yang, Changduk; Li, Yongfang

    2016-04-06

    Non-fullerene polymer solar cells (PSCs) with solution-processable n-type organic semiconductor (n-OS) as acceptor have seen rapid progress recently owing to the synthesis of new low bandgap n-OS, such as ITIC. To further increase power conversion efficiency (PCE) of the devices, it is of a great challenge to develop suitable polymer donor material that matches well with the low bandgap n-OS acceptors thus providing complementary absorption and nanoscaled blend morphology, as well as suppressed recombination and minimized energy loss. To address this challenge, we synthesized three medium bandgap 2D-conjugated bithienyl-benzodithiophene-alt-fluorobenzotriazole copolymers J52, J60, and J61 for the application as donor in the PSCs with low bandgap n-OS ITIC as acceptor. The three polymers were designed with branched alkyl (J52), branched alkylthio (J60), and linear alkylthio (J61) substituent on the thiophene conjugated side chain of the benzodithiophene (BDT) units for studying effect of the substituents on the photovoltaic performance of the polymers. The alkylthio side chain, red-shifted absorption down-shifted the highest occupied molecular orbital (HOMO) level and improved crystallinity of the 2D conjugated polymers. With linear alkylthio side chain, the tailored polymer J61 exhibits an enhanced JSC of 17.43 mA/cm(2), a high VOC of 0.89 V, and a PCE of 9.53% in the best non-fullerene PSCs with the polymer as donor and ITIC as acceptor. To the best of our knowledge, the PCE of 9.53% is one of the highest values reported in literature to date for the non-fullerene PSCs. The results indicate that J61 is a promising medium bandgap polymer donor in non-fullerene PSCs.

  5. Core/Shell Conjugated Polymer/Quantum Dot Composite Nanofibers through Orthogonal Non-Covalent Interactions

    Directory of Open Access Journals (Sweden)

    Brad W. Watson

    2016-11-01

    Full Text Available Nanostructuring organic polymers and organic/inorganic hybrid materials and controlling blend morphologies at the molecular level are the prerequisites for modern electronic devices including biological sensors, light emitting diodes, memory devices and solar cells. To achieve all-around high performance, multiple organic and inorganic entities, each designed for specific functions, are commonly incorporated into a single device. Accurate arrangement of these components is a crucial goal in order to achieve the overall synergistic effects. We describe here a facile methodology of nanostructuring conjugated polymers and inorganic quantum dots into well-ordered core/shell composite nanofibers through cooperation of several orthogonal non-covalent interactions including conjugated polymer crystallization, block copolymer self-assembly and coordination interactions. Our methods provide precise control on the spatial arrangements among the various building blocks that are otherwise incompatible with one another, and should find applications in modern organic electronic devices such as solar cells.

  6. Photovoltaic cells made from conjugated polymers infiltrated into ordered nanoporous hosts

    Science.gov (United States)

    Coakley, Kevin M.

    Semiconducting (conjugated) polymers have several properties which make them ideal candidates for use in low-cost photovoltaic (PV) cells, including their typically high (105 cm-1) optical absorption coefficients, their ability to be cast from solution using a variety of wet-processing techniques, and the ability to tune their band gap. While most approaches for making conjugated polymer-based PV cells involve randomly intermixing the polymers with electron acceptors that act as sites for exciton dissociation, we have sought to obtain a more optimized morphology of the blended materials through a self-assembly technique. In the first half of this dissertation, we describe our preliminary attempts to make PV cells from conjugated polymers infiltrated into a self-assembled mesoporous titanic (TiO 2) electron acceptor that is ordered on the nanometer length scale. We first present a procedure for fabricating films of mesoporous TiO 2 and then show how its pores can be filled with a conjugated polymer, regioregular poly(3-hexylthiophene) (P3HT). In these films we have achieved precise control of the morphology of the two materials that has not yet been achieved elsewhere. However, as discussed subsequently, the photovoltaic performance of these films has not yet reached the level achieved by other types of conjugated polymer-based PV cells, with a maximum achieved power efficiency of approximately 0.45%. In the second half of this dissertation, we embark on a more fundamental study of the materials requirements for efficient polymer photovoltaics, including models that show how the maximum achievable power efficiency is limited by energy loss during forward electron transfer, and how the maximum achievable photocurrent is limited by the limiting carrier mobility and back electron transfer. Our modeling suggests that, for a back recombination time constant of 1 mus, a limiting carrier mobility of 10-3--10 -2 cm2/Vs is required in order to achieve a large photocurrent

  7. Effect of oligonucleic acid (ONA) backbone features on assembly of ONA-star polymer conjugates: a coarse-grained molecular simulation study.

    Science.gov (United States)

    Condon, Joshua E; Jayaraman, Arthi

    2017-10-04

    Understanding the impact of incorporating new physical and chemical features in oligomeric DNA mimics, termed generally as "oligonucleic acids" (ONAs), on their structure and thermodynamics will be beneficial in designing novel materials for a variety of applications. In this work, we conduct coarse-grained molecular simulations of ONA-star polymer conjugates with varying ONA backbone flexibility, ONA backbone charge, and number of arms in the star polymer at a constant ONA strand volume fraction to elucidate the effect of these design parameters on the thermodynamics and assembly of multi-arm ONA-star polymer conjugates. We quantify the thermo-reversible behavior of the ONA-star polymer conjugates by quantifying the hybridization of the ONA strands in the system as a function of temperature (i.e. melting curve). Additionally, we characterize the assembly of the ONA-star polymer conjugates by tracking cluster formation and percolation as a function of temperature, as well as cluster size distribution at temperatures near the assembly transition region. The key results are as follows. The melting temperature (T m ) of the ONA strands decreases upon going from a neutral to a charged ONA backbone and upon increasing flexibility of the ONA backbone. Similar behavior is seen for the assembly transition temperature (T a ) with varying ONA backbone charge and flexibility. While the number of arms in the ONA-star polymer conjugate has a negligible effect on the ONA T m in these systems, as the number of ONA-star polymer arms increase, the assembly temperature T a increases and local ordering in the assembled state improves. By understanding how factors like ONA backbone charge, backbone flexibility, and ONA-star polymer conjugate architecture impact the behavior of ONA-star polymer conjugate systems, we can better inform how the selection of ONA chemistry will influence resulting ONA-star polymer assembly.

  8. Conjugated Polymer Actuators: Prospects and Limitations

    DEFF Research Database (Denmark)

    Skaarup, Steen

    2007-01-01

    Actuators constructed with a conjugated polymer as the active part have been predicted to have a number of highly desirable properties: Large mechanical strength, high power density, i.e. high actuation speeds possible, sufficient maximum strain values, high reversibility and safe, low voltages (1...

  9. Analytical characterization of polymer-drug conjugates

    International Nuclear Information System (INIS)

    Rizzo, V.; Gigli, M.; Pinciroli, V.

    1998-01-01

    A few polymeric conjugates of antitumor drugs have been recently developed in view of possible therapeutic advantages: solubilization of sparingly soluble drugs in water, improvement of therapeutic index, organ targeting through a second chemical species bound to the same polymeric chain. In this article it's described the analytical approach used in the characterization of the conjugates for chemical identity, purity and strength of the contained active ingredient. The techniques are: high field NMR and size exclusion chromatography with non-aqueous mobile phase for identity; selective hydrolysis and HPLC for strength and purity. A complete and reliable picture is thus obtained both for qualitative and for quantitative aspects. This is an important step forward in the direction of further development and marketing of polymer-drug conjugates [it

  10. Conjugated polymer energy level shifts in lithium-ion battery electrolytes.

    Science.gov (United States)

    Song, Charles Kiseok; Eckstein, Brian J; Tam, Teck Lip Dexter; Trahey, Lynn; Marks, Tobin J

    2014-11-12

    The ionization potentials (IPs) and electron affinities (EAs) of widely used conjugated polymers are evaluated by cyclic voltammetry (CV) in conventional electrochemical and lithium-ion battery media, and also by ultraviolet photoelectron spectroscopy (UPS) in vacuo. By comparing the data obtained in the different systems, it is found that the IPs of the conjugated polymer films determined by conventional CV (IPC) can be correlated with UPS-measured HOMO energy levels (EH,UPS) by the relationship EH,UPS = (1.14 ± 0.23) × qIPC + (4.62 ± 0.10) eV, where q is the electron charge. It is also found that the EAs of the conjugated polymer films measured via CV in conventional (EAC) and Li(+) battery (EAB) media can be linearly correlated by the relationship EAB = (1.07 ± 0.13) × EAC + (2.84 ± 0.22) V. The slopes and intercepts of these equations can be correlated with the dielectric constants of the polymer film environments and the redox potentials of the reference electrodes, as modified by the surrounding electrolyte, respectively.

  11. Thermocleavable pi-Conjugated polymers. Synthesis and photovoltaic applications

    Energy Technology Data Exchange (ETDEWEB)

    Helgesen, M

    2009-10-15

    Polymer solar cells (plastic solar cells) have seen remarkable improvements in recent years where power conversion efficiencies of up to 6% have been reported for small area devices. However in terms of stability polymer solar cells degrade during illumination and in the dark leading to operational lifetimes that are generally very poor. There has been a recent interest in the operational stability of devices and more importantly on the understanding of why devices and materials break down. This has lead to the discovery of a new class of materials that enable exceptionally long device lifetimes (>20000 hours). This Ph.D. thesis describes the synthesis, characterization and photovoltaic applications of these novel polymer materials. A key feature of these materials is that solubilizing thermocleavable alkyl ester side chains are introduced on the polymer backbone. The side chains make the polymer soluble in organic solvents and allow film formation via solution processing. Subsequently they can be removed by heating in a post-processing step forming a harder insoluble material with enhanced stability. These new thermocleavable materials can potentially offer higher chromophore density, higher level processing and improved stability in a solar cell device. Methods are developed for the incorporation of alkoxy chains and thermocleavable ester groups on the benzothiadiazole and the thiophene units in an attempt to evolve the PDTBT system to a more advanced level. The synthesis and photovoltaic applications of the PDTTP and PDTBT systems is described. (author)

  12. Synthesis and Characterisation of Biocompatible Polymer-Conjugated Magnetic Beads for Enhancement Stability of Urease.

    Science.gov (United States)

    Doğaç, Yasemin Ispirli; Teke, Mustafa

    2016-04-01

    We reported natural polymer-conjugated magnetic featured urease systems for removal of urea effectively. The optimum temperature (20-60 °C), optimum pH (3.0-10.0), kinetic parameters, thermal stability (4-70 °C), pH stability (4.0-9.0), operational stability (0-250 min), reusability (18 times) and storage stability (24 weeks) were studied for characterisation of the urease-encapsulated biocompatible polymer-conjugated magnetic beads. Also, the surface groups and chemical structure of the magnetic beads were determined by using attenuated total reflectance Fourier transform infrared spectroscopy (ATR-FTIR). The all urease-encapsulated magnetic beads protected their stability of 30-45 % relative activity at 70 °C. A significant increase was observed at their pH stability compared with the free urease for both acidic and alkaline medium. Besides this, their repeatability activity were approximately 100 % during 4(th) run. They showed residual activity of 50 % after 16 weeks. The importance of this work is enhancement stability of immobilised urease by biocompatible polymer-conjugated magnetic beads for the industrial application based on removal of urea.

  13. Exploration of a Doxorubicin-Polymer Conjugate in Lipid-Polymer Hybrid Nanoparticle Drug Delivery

    Science.gov (United States)

    Lough, Emily

    Nanoparticle (NP) drug delivery is a major focus in the research community because of its potential to use existing drugs in safer and more effective ways. Chemotherapy encapsulation in NPs shields the drug from the rest of the body while it is within the NP, with less systemic exposure leading to fewer off-target effects of the drug. However, passive loading of drugs into NPs is a suboptimal method, often leading to burst release upon administration. This work explores the impact of incorporating the drug-polymer conjugate doxorubicin-poly (lactic-co-glycolic) acid (Dox-PLGA) into a lipid-polymer hybrid nanoparticle (LPN). The primary difference in using a drug-polymer conjugate for NP drug delivery is the drug's release kinetics. Dox-PLGA LPNs showed a more sustained and prolonged release profile over 28 days compared to LPNs with passively loaded, unconjugated doxorubicin. This sustained release translates to cytotoxicity; when systemic circulation was simulated using dialysis, Dox-PLGA LPNs retained their cytotoxicity at a higher level than the passively loaded LPNs. The in vivo implication of preserving cytotoxic potency through a slower release profile is that the majority of Dox delivered via Dox-PLGA LPNs will be kept within the LPN until it reaches the tumor. This will result in fewer systemic side effects and more effective treatments given the higher drug concentration at the tumor site. An intriguing clinical application of this drug delivery approach lies in using Dox-PLGA LPNs to cross the blood-brain barrier (BBB). The incorporation of Dox-PLGA is hypothesized to have a protective effect on the BBB as its slow release profile will prevent drug from harming the BBB. Using induced pluripotent stem cells differentiated to human brain microvascular endothelial cells that comprise the BBB, the Dox-PLGA LPNs were shown to be less destructive to the BBB than their passively loaded counterparts. Dox-PLGA LPNs showed superior cytotoxicity against plated tumor

  14. Incorporating functionalized polyethylene glycol lipids into reprecipitated conjugated polymer nanoparticles for bioconjugation and targeted labeling of cells

    Science.gov (United States)

    Kandel, Prakash K.; Fernando, Lawrence P.; Ackroyd, P. Christine; Christensen, Kenneth A.

    2011-03-01

    We report a simple and rapid method to prepare extremely bright, functionalized, stable, and biocompatible conjugated polymer nanoparticles incorporating functionalized polyethylene glycol (PEG) lipids by reprecipitation. These nanoparticles retain the fundamental spectroscopic properties of conjugated polymer nanoparticles prepared without PEG lipid, but demonstrate greater hydrophilicity and quantum yield compared to unmodified conjugated polymer nanoparticles. The sizes of these nanoparticles, as determined by TEM, were 21-26 nm. Notably, these nanoparticles were prepared with several PEG lipid functional end groups, including biotin and carboxy moieties that can be easily conjugated to biomolecules. We have demonstrated the availability of these end groups for functionalization using the interaction of biotin PEG lipid conjugated polymer nanoparticles with streptavidin. Biotinylated PEG lipid conjugated polymer nanoparticles bound streptavidin-linked magnetic beads, while carboxy and methoxy PEG lipid modified nanoparticles did not. Similarly, biotinylated PEG lipid conjugated polymer nanoparticles bound streptavidin-coated glass slides and could be visualized as diffraction-limited spots, while nanoparticles without PEG lipid or with non-biotin PEG lipid end groups were not bound. To demonstrate that nanoparticle functionalization could be used for targeted labelling of specific cellular proteins, biotinylated PEG lipid conjugated polymer nanoparticles were bound to biotinylated anti-CD16/32 antibodies on J774A.1 cell surface receptors, using streptavidin as a linker. This work represents the first demonstration of targeted delivery of conjugated polymer nanoparticles and demonstrates the utility of these new nanoparticles for fluorescence based imaging and sensing.We report a simple and rapid method to prepare extremely bright, functionalized, stable, and biocompatible conjugated polymer nanoparticles incorporating functionalized polyethylene glycol (PEG

  15. Compositions for directed alignment of conjugated polymers

    Science.gov (United States)

    Kim, Jinsang; Kim, Bong-Gi; Jeong, Eun Jeong

    2016-04-19

    Conjugated polymers (CPs) achieve directed alignment along an applied flow field and a dichroic ratio of as high as 16.67 in emission from well-aligned thin films and fully realized anisotropic optoelectronic properties of CPs in field-effect transistor (FET).

  16. Simple Protein Modification Using Zwitterionic Polymer to Mitigate the Bioactivity Loss of Conjugated Insulin.

    Science.gov (United States)

    Xie, Jinbing; Lu, Yang; Wang, Wei; Zhu, Hui; Wang, Zhigang; Cao, Zhiqiang

    2017-06-01

    Polymer-protein conjugation has been extensively explored toward a better protein drug with improved pharmacokinetics. However, a major problem with polymer-protein conjugation is that the polymers drastically reduce the bioactivity of the modified protein. There is no perfect solution to prevent the bioactivity loss, no matter the polymer is conjugated in a non-site specific way, or a more complex site-specific procedure. Here the authors report for the first time that when zwitterionic carboxybetaine polymer (PCB) is conjugated to insulin through simple conventional coupling chemistry. The resulting PCB-insulin does not show a significant reduction of in vitro bioactivity. The obtained PCB-insulin shows two significant advantages as a novel pharmaceutical agent. First, its therapeutic performance is remarkable. For PCB-insulin, there is a 24% increase of in vivo pharmacological activity of lowering blood glucose compared with native insulin. Such uncommonly seen increase has rarely been reported and is expected to be due to both the improved pharmacokinetics and retained bioactivity of PCB-insulin. Second, the production is simple from manufacturing standpoints. Conjugation procedure involves only one-step coupling reaction without complex site-specific linkage technique. The synthesized PCB-insulin conjugates do not require chromatographic separation to purify and obtain particular isoforms. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. RIR-MAPLE deposition of conjugated polymers and hybrid nanocomposites for application to optoelectronic devices

    International Nuclear Information System (INIS)

    Stiff-Roberts, Adrienne D.; Pate, Ryan; McCormick, Ryan; Lantz, Kevin R.

    2012-01-01

    Resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) is a variation of pulsed laser deposition that is useful for organic-based thin films because it reduces material degradation by selective absorption of infrared radiation in the host matrix. A unique emulsion-based RIR-MAPLE approach has been developed that reduces substrate exposure to solvents and provides controlled and repeatable organic thin film deposition. In order to establish emulsion-based RIR-MAPLE as a preferred deposition technique for conjugated polymer or hybrid nanocomposite optoelectronic devices, studies have been conducted to demonstrate the value added by the approach in comparison to traditional solution-based deposition techniques, and this work will be reviewed. The control of hybrid nanocomposite thin film deposition, and the photoconductivity in such materials deposited using emulsion-based RIR-MAPLE, will also be reviewed. The overall result of these studies is the demonstration of emulsion-based RIR-MAPLE as a viable option for the fabrication of conjugated polymer and hybrid nanocomposite optoelectronic devices that could yield improved device performance.

  18. Particle-in-a-box model of exciton absorption and electroabsorption in conjugated polymers

    Science.gov (United States)

    Pedersen, Thomas G.

    2000-12-01

    The recently proposed particle-in-a-box model of one-dimensional excitons in conjugated polymers is applied in calculations of optical absorption and electroabsorption spectra. It is demonstrated that for polymers of long conjugation length a superposition of single exciton resonances produces a line shape characterized by a square-root singularity in agreement with experimental spectra near the absorption edge. The effects of finite conjugation length on both absorption and electroabsorption spectra are analyzed.

  19. Exploring the origin of high optical absorption in conjugated polymers

    KAUST Repository

    Vezie, Michelle S.; Few, Sheridan; Meager, Iain; Pieridou, Galatia; Dö rling, Bernhard; Ashraf, Raja Shahid; Goñ i, Alejandro R.; Bronstein, Hugo; McCulloch, Iain; Hayes, Sophia C.; Campoy-Quiles, Mariano; Nelson, Jenny

    2016-01-01

    The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure.

  20. Exploring the origin of high optical absorption in conjugated polymers

    KAUST Repository

    Vezie, Michelle S.

    2016-05-16

    The specific optical absorption of an organic semiconductor is critical to the performance of organic optoelectronic devices. For example, higher light-harvesting efficiency can lead to higher photocurrent in solar cells that are limited by sub-optimal electrical transport. Here, we compare over 40 conjugated polymers, and find that many different chemical structures share an apparent maximum in their extinction coefficients. However, a diketopyrrolopyrrole-thienothiophene copolymer shows remarkably high optical absorption at relatively low photon energies. By investigating its backbone structure and conformation with measurements and quantum chemical calculations, we find that the high optical absorption can be explained by the high persistence length of the polymer. Accordingly, we demonstrate high absorption in other polymers with high theoretical persistence length. Visible light harvesting may be enhanced in other conjugated polymers through judicious design of the structure.

  1. Color tunable hybrid light-emitting diodes based on perovskite quantum dot/conjugated polymer

    Science.gov (United States)

    Germino, José C.; Yassitepe, Emre; Freitas, Jilian N.; Santiago, Glauco M.; Bonato, Luiz Gustavo; de Morais, Andréia; Atvars, Teresa D. Z.; Nogueira, Ana F.

    2017-08-01

    Inorganic organic metal halide perovskite materials have been investigated for several technological applications, such as photovoltaic cells, lasers, photodetectors and light emitting diodes (LEDs), either in the bulk form or as colloidal nanoparticles. Recently, all inorganic Cesium Lead Halide (CsPbX3, X=Cl,Br, I) perovskite quantum dots (PQDs) were reported with high photoluminescence quantum yield with narrow emission lines in the visible wavelengths. Here, green-emitting perovskite quantum dots (PQDs) prepared by a synthetic method based on a mixture of oleylamine and oleic acid as surfactants were applied in the electroluminescent layer of hybrid LEDs in combination with two different conjugated polymers: polyvinylcarbazole (PVK) or poly(9,9-di-n-octylfluorenyl-2,7-diyl) (PFO). The performance of the diodes and the emission color tuning upon dispersion of different concentrations of the PQDs in the polymer matrix is discussed. The presented approach aims at the combination of the optical properties of the PQDs and their interaction with wide bandgap conjugated polymers, associated with the solution processing ability of these materials.

  2. Stabilization of Resveratrol in Blood Circulation by Conjugation to mPEG and mPEG-PLA Polymers: Investigation of Conjugate Linker and Polymer Composition on Stability, Metabolism, Antioxidant Activity and Pharmacokinetic Profile

    Science.gov (United States)

    Siddalingappa, Basavaraj; Benson, Heather A. E.; Brown, David H.; Batty, Kevin T.; Chen, Yan

    2015-01-01

    Resveratrol is naturally occurring phytochemical with diverse biological activities such as chemoprevention, anti-inflammatory, anti-cancer, anti-oxidant. But undergoes rapid metabolism in the body (half life 0.13h). Hence Polymer conjugation utilizing different chemical linkers and polymer compositions was investigated for enhanced pharmacokinetic profile of resveratrol. Ester conjugates such as α-methoxy-ω-carboxylic acid poly(ethylene glycol) succinylamide resveratrol (MeO-PEGN-Succ-RSV) (2 and 20 kDa); MeO-PEG succinyl ester resveratrol (MeO-PEGO-Succ-RSV) (2 kDa); α-methoxy poly(ethylene glycol)-co-polylactide succinyl ester resveratrol (MeO-PEG-PLAO-Succ-RSV) (2 and 6.6kDa) were prepared by carbodiimide coupling reactions. Resveratrol-PEG ethers (2 and 5 kDa) were synthesized by alkali-mediated etherification. All polymer conjugates were fully characterized in vitro and the pharmacokinetic profile of selected conjugates was characterized in rats. Buffer and plasma stability of conjugates was dependent on polymer hydrophobicity, aggregation behavior and PEG corona, with MeO-PEG-PLAO-Succ-RSV (2 kDa) showing a 3h half-life in rat plasma in vitro. Polymer conjugates irrespective of linker chemistry protected resveratrol against metabolism in vitro. MeO-PEG-PLAO-Succ-RSV (2 kDa), Resveratrol-PEG ether (2 and 5 kDa) displayed improved pharmacokinetic profiles with significantly higher plasma area under curve (AUC), slower clearance and smaller volume of distribution, compared to resveratrol. PMID:25799413

  3. Impact of Backbone Fluorination on π-Conjugated Polymers in Organic Photovoltaic Devices: A Review

    Directory of Open Access Journals (Sweden)

    Nicolas Leclerc

    2016-01-01

    Full Text Available Solution-processed bulk heterojunction solar cells have experienced a remarkable acceleration in performances in the last two decades, reaching power conversion efficiencies above 10%. This impressive progress is the outcome of a simultaneous development of more advanced device architectures and of optimized semiconducting polymers. Several chemical approaches have been developed to fine-tune the optoelectronics and structural polymer parameters required to reach high efficiencies. Fluorination of the conjugated polymer backbone has appeared recently to be an especially promising approach for the development of efficient semiconducting polymers. As a matter of fact, most currently best-performing semiconducting polymers are using fluorine atoms in their conjugated backbone. In this review, we attempt to give an up-to-date overview of the latest results achieved on fluorinated polymers for solar cells and to highlight general polymer properties’ evolution trends related to the fluorination of their conjugated backbone.

  4. Methyllithium-Doped Naphthyl-Containing Conjugated Microporous Polymer with Enhanced Hydrogen Storage Performance.

    Science.gov (United States)

    Xu, Dan; Sun, Lei; Li, Gang; Shang, Jin; Yang, Rui-Xia; Deng, Wei-Qiao

    2016-06-01

    Hydrogen storage is a primary challenge for using hydrogen as a fuel. With ideal hydrogen storage kinetics, the weak binding strength of hydrogen to sorbents is the key barrier to obtain decent hydrogen storage performance. Here, we reported the rational synthesis of a methyllithium-doped naphthyl-containing conjugated microporous polymer with exceptional binding strength of hydrogen to the polymer guided by theoretical simulations. Meanwhile, the experimental results showed that isosteric heat can reach up to 8.4 kJ mol(-1) and the methyllithium-doped naphthyl-containing conjugated microporous polymer exhibited an enhanced hydrogen storage performance with 150 % enhancement compared with its counterpart naphthyl-containing conjugated microporous polymer. These results indicate that this strategy provides a direction for design and synthesis of new materials that meet the US Department of Energy (DOE) hydrogen storage target. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Scanning-tunneling spectroscopy on conjugated polymer films

    NARCIS (Netherlands)

    Kemerink, M.; Alvarado, S.F.; Koenraad, P.M.; Janssen, R.A.J.; Salemink, H.W.M.; Wolter, J.H.; Blom, P.W.M.

    2003-01-01

    Scanning-tunneling spectroscopy experiments have been performed on conjugated polymer films and have been compared to a three-dimensional numerical model for charge injection and transport. It is found that field enhancement near the tip apex leads to significant changes in the injected current,

  6. Theoretical and computational studies of excitons in conjugated polymers

    Science.gov (United States)

    Barford, William; Bursill, Robert J.; Smith, Richard W.

    2002-09-01

    We present a theoretical and computational analysis of excitons in conjugated polymers. We use a tight-binding model of π-conjugated electrons, with 1/r interactions for large r. In both the weak-coupling limit (defined by W>>U) and the strong-coupling limit (defined by Wparticle models. We compare these to density matrix renormalization group (DMRG) calculations, and find good agreement in the extreme limits. We use these analytical results to interpret the DMRG calculations in the intermediate-coupling regime (defined by W~U), most applicable to conjugated polymers. We make the following conclusions. (1) In the weak-coupling limit the bound states are Mott-Wannier excitons, i.e., conduction-band electrons bound to valence-band holes. Singlet and triplet excitons whose relative wave functions are odd under a reflection of the relative coordinate are degenerate. Thus, the 2 1A+g and 1 3A-g states are degenerate in this limit. (2) In the strong-coupling limit the bound states are Mott-Hubbard excitons, i.e., particles in the upper Hubbard band bound to holes in the lower Hubbard band. These bound states occur in doublets of even and odd parity excitons. Triplet excitons are magnons bound to the singlet excitons, and hence are degenerate with their singlet counterparts. (3) In the intermediate-coupling regime Mott-Wannier excitons are the more appropriate description for large dimerization, while for the undimerized chain Mott-Hubbard excitons are the correct description. For dimerizations relevant to polyacetylene and polydiacetylene both Mott-Hubbard and Mott-Wannier excitons are present. (4) For all coupling strengths an infinite number of bound states exist for 1/r interactions for an infinite polymer. As a result of the discreteness of the lattice and the restrictions on the exciton wave functions in one dimension, the progression of states does not follow the Rydberg series. In practice, excitons whose particle-hole separation exceeds the length of the polymer

  7. Photochemical stability of π-conjugated polymers for polymer solar cells: a rule of thumb

    DEFF Research Database (Denmark)

    Manceau, Matthieu; Bundgaard, Eva; Carlé, Jon Eggert

    2011-01-01

    A comparative photochemical stability study of a wide range of π-conjugated polymers relevant to polymer solar cells is presented. The behavior of each material has been investigated under simulated sunlight (1 sun, 1000 W m−2, AM 1.5G) and ambient atmosphere. Degradation was monitored during age...... ageing combining UV-visible and infrared spectroscopies. From the comparison of the collected data, the influence of the polymer chemical structure on its stability has been discussed. General rules relative to the polymer structure–stability relationship are proposed....

  8. α-Methylprednisolone conjugated cyclodextrin polymer-based nanoparticles for rheumatoid arthritis therapy

    Directory of Open Access Journals (Sweden)

    Jungyeon Hwang

    2008-10-01

    Full Text Available Jungyeon Hwang1, Kathleen Rodgers2, James C Oliver3, Thomas Schluep11Insert Therapeutics, Inc., Pasadena, CA, USA; 2Livingston Research Institute, Los Angeles, CA, USA; James C Oliver, Peptagen, Inc., Raleigh, NC USAAbstract: A glycinate derivative of α-methylprednisolone (MP was prepared and conjugated to a linear cyclodextrin polymer (CDP with a loading of 12.4% w/w. The polymer conjugate (CDP-MP self-assembled into nanoparticles with a size of 27 nm. Release kinetics of MP from the polymer conjugate showed a half-life (t1/2 of 50 h in phosphate buffer solution (PBS and 19 h in human plasma. In vitro, the proliferation of human lymphocytes was suppressed to a similar extent but with a delayed effect when CDP-MP was compared with free MP. In vivo, CDP-MP was administered intravenously to mice with collagen-induced arthritis and compared with free MP. CDP-MP was administered weekly for six weeks (0.07, 0.7, and 7 mg/kg/week and MP was administered daily for six weeks (0.01, 0.1, and 1 mg/kg/day. Body weight changes were minimal in all animals. After 28 days, a significant decrease in arthritis score was observed in animals treated weekly with an intermediate or high dose of CDP-MP. Additionally, dorsoplantar swelling was reduced to baseline in animals treated with CDP-MP at the intermediate and high dose level. Histological evaluation showed a reduction in synovitis, pannus formation and disruption of architecture at the highest dose level of CDP-MP. MP administered daily at equivalent cumulative doses showed minimal efficacy in this model. This study demonstrates that conjugation of MP to a cyclodextrin-polymer may improve its efficacy, leading to lower doses and less frequent administration for a safer and more convenient management of rheumatoid arthritis.Keywords: α-methylprednisolone (MP, cyclodextrin polymer (CDP, polymer conjugate (CDP-MP, rheumatoid arthritis (RA, enhanced permeability and retention effect (EPR

  9. Impact of morphology on polaron delocalization in a semicrystalline conjugated polymer

    KAUST Repository

    Steyrleuthner, Robert

    2016-12-20

    We investigate the delocalization of holes in the semicrystalline conjugated polymer poly(2,5-bis(3-alkylthiophene-2-yl)thieno[3,2-b]thiophene) (PBTTT) by directly measuring the hyperfine coupling between photogenerated polarons and bound nuclear spins using electron nuclear double resonance spectroscopy. An extrapolation of the corresponding oligomer spectra reveals that charges tend to delocalize over 4.0-4.8 nm with delocalization strongly dependent on molecular order and crystallinity of the PBTTT polymer thin films. Density functional theory calculations of hyperfine couplings confirm that long-range corrected functionals appropriately describe the change in coupling strength with increasing oligomer size and agree well with the experimentally measured polymer limit. Our discussion presents general guidelines illustrating the various pitfalls and opportunities when deducing polaron localization lengths from hyperfine coupling spectra of conjugated polymers.

  10. Thiolated polymers--thiomers: development and in vitro evaluation of chitosan-thioglycolic acid conjugates.

    Science.gov (United States)

    Kast, C E; Bernkop-Schnürch, A

    2001-09-01

    The aim of this study was to improve mucoadhesive properties of chitosan by the covalent attachment of thiol moieties to this cationic polymer. Mediated by a carbodiimide, thioglycolic acid (TGA) was covalently attached to chitosan. This was achieved by the formation of amide bonds between the primary amino groups of the polymer and the carboxylic acid group of TGA. Dependent on the pH-value and the weight ratio of polymer to TGA during the coupling reaction the resulting thiolated polymers, the so-called thiomers, displayed 6.58, 9.88, 27.44, and 38.23 micromole thiol groups per gram polymer. Tensile studies carried out with these chitosan-TGA conjugates on freshly excised porcine intestinal mucosa demonstrated a 6.3-, 8.6-, 8.9-, and 10.3-fold increase in the total work of adhesion (TWA) compared to the unmodified polymer, respectively. In contrast, the combination of chitosan and free unconjugated TGA showed almost no mucoadhesion. These data were in good correlation with further results obtained by another mucoadhesion test demonstrating a prolonged residence time of thiolated chitosan on porcine mucosa. The swelling behavior of all conjugates was thereby exactly in the same range as for an unmodified polymer pretreated in the same way. Furthermore, it could be shown that chitosan-TGA conjugates are still biodegradable by the glycosidase lysozyme. According to these results. chitosan-TGA conjugates represent a promising tool for the development of mucoadhesive drug delivery systems.

  11. Novel Luminescent Multilayer Films Containing π-Conjugated Anionic Polymer with Electronic Microenvironment

    Directory of Open Access Journals (Sweden)

    Tianlei Wang

    2016-09-01

    Full Text Available Layered double hydroxides (LDHs, luminescent π-conjugated anionic polymer and montmorillonite (MMT were orderly assembled into luminescent multilayer films via layer-by-layer self-assembly method. The electronic microenvironment (EME, the structure of which is like a traditional capacitor, can be constructed by exfoliated LDHs or MMT nanosheets. In addition, the rigid inorganic laminated configuration can offer stable surroundings between the interlayers. As a result, we conclude that EME can extend the luminescent lifespans of multilayer films substantially, due to affecting relaxation times of π-conjugated anionic polymer. Consequently, because of the remarkable impact on better photoemission behaviors of luminescent π-conjugated anionic polymer, EME assembled by LDHs or MMT nanosheets have had high hopes attached to them. They are expected to have the potential for designing, constructing, and investigating novel light-emitting thin films.

  12. Modelling the effect of nonplanarity on charge transport along conjugated polymer chains

    International Nuclear Information System (INIS)

    Correia, Helena M.G.; Ramos, Marta M.D.

    2007-01-01

    Conjugated polymers show interesting properties that make them appropriated for nanoelectronics. Several studies of poly(p-phenylene vinylene) (PPV) have suggested that each polymer chain consists of several planar segments, with conjugation length of nanoscale dimension, linked by twists or kinks. A pronounced twist between two planar segments in a PPV chain not only causes loss of main-chain conjugation but it may also alter electron and hole mobility along the chain, which has further implications for the percolation of charge through the polymer film. We used self-consistent quantum molecular dynamics calculations to provide information on the electric field needed to move the injected charges (either electrons or holes) along the planar segments of PPV and to cross the twist between two planar segments perpendicular to each other. Field-dependent charge mobility was also estimated for conjugated segments of various lengths. Our results suggest that electrons can cross the twist between adjacent planar segments for lower applied electric fields than holes if there is no more than one electronic charge (electron or hole) on the PPV chain, otherwise similar fields are needed

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

    KAUST Repository

    Dimitrov, Stoichko; Schroeder, Bob; Nielsen, Christian; Bronstein, Hugo; Fei, Zhuping; McCulloch, Iain; Heeney, Martin; Durrant, James

    2016-01-01

    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

  14. Stiffness, strength and adhesion characterization of electrochemically deposited conjugated polymer films

    Science.gov (United States)

    Qu, Jing; Ouyang, Liangqi; Kuo, Chin-chen; Martin, David C.

    2015-01-01

    Conjugated polymers such as poly(3,4-ethylenedioxythiphene) (PEDOT) are of interest for a variety of applications including interfaces between electronic biomedical devices and living tissue. The mechanical properties, strength, and adhesion of these materials to solid substrates are all vital for long-term applications. We have been developing methods to quantify the mechanical properties of conjugated polymer thin films. In this study the stiffness, strength and the interfacial shear strength (adhesion) of electrochemically deposited PEDOT and PEDOT-co-1,3,5-tri[2-(3,4-ethylene dioxythienyl)]-benzene (EPh) were studied. The estimated Young’s modulus of the PEDOT films was 2.6 ± 1.4 GPa, and the strain to failure was around 2%. The tensile strength was measured to be 56 ± 27 MPa. The effective interfacial shear strength was estimated with a shear-lag model by measuring the crack spacing as a function of film thickness. For PEDOT on gold/palladium-coated hydrocarbon film substrates an interfacial shear strength of 0.7 ± 0.3 MPa was determined. The addition of 5 mole% of a tri-functional EDOT crosslinker (EPh) increased the tensile strength of the films to 283 ± 67 MPa, while the strain to failure remained about the same (2%). The effective interfacial shear strength was increased to 2.4 ± 0.6 MPa. PMID:26607768

  15. Realization of large area flexible fullerene - conjugated polymer photocells: a route to plastic solar cells

    NARCIS (Netherlands)

    Brabec, C.J.; Padinger, F.; Hummelen, J.C.; Janssen, R.A.J.; Sariciftci, N.S.

    1999-01-01

    Bulk donor — acceptor heterojunctions between conjugated polymers and fullerenes have been utilized for photovoltaic devices with quantum efficiencies of around 1%. These devices are based on the photoinduced, ultrafast electron transfer between non degenerate ground state conjugated polymers and

  16. A possibility for generation of two species of charge carriers along main-chain and side-chains for a π-conjugated polymer

    International Nuclear Information System (INIS)

    Kudo, Yuki; Kawabata, Kohsuke; Goto, Hiromasa

    2013-01-01

    Iodide doping produces charge carriers in π-conjugated polymers. Solitons can be generated in the case of polyacetylene, and polarons in the case of aromatic-type conjugated polymers. We synthesized a conjugated main-chain/side-chain polymer, which consists of polyene in the main-chain and aromatic-type conjugated units in the side-chains. Based on the SSH (Su, Schrieffer, Heeger) theoretical model of solitons in one-dimensional conjugated polymers, we experimentally carried out chemical doping to the main-chain/side-chains conjugated polymer. Generation of the charge carriers was examined by electron spin resonance spectroscopy. This study may lead to realization of a dual doping system of solitons and polarons in π-conjugation expanded to two-dimensional directions in polymers.

  17. Synthesis and characterization of a cysteine xyloglucan conjugate as mucoadhesive polymer

    Directory of Open Access Journals (Sweden)

    Mangesh Bhalekar

    2013-06-01

    Full Text Available The aim of this study was to improve the mucoadhesive potential of xyloglucan polymer by the covalent attachment of cysteine as thiol moiety. The parent polymer xyloglucan was chemically modified by introducing sulphydryl bearing compound L-cysteine HCl. Different batches of xyloglucan-cysteine conjugates were prepared at varying reaction pH (2-6 and evaluated for optimum thiol incorporation, disulphide group content, swelling behavior, rheological properties and mucoadhesive properties. The obtained conjugates characterized in vitro by quantification of immobilized thiol groups; showed maximum thiol incorporation on xyloglucan (7.67 ± 0.14 % at pH 5. The disulphide group content was found maximum (2.83 ± 0.12 at pH 6. The water uptake at end of 4 h was 5.0 for xyloglucan and was found to decrease in thiolated derivatives with increase in thiolation. Mucoadhesion studies revealed that mucoadhesion of xyloglucan-cysteine conjugate increased more than twice compared to the unmodified polymer. The viscosity of thiomer was more than that of xyloglucan because of formation of disulphide bonds.

  18. Peptides, proteins and peptide/protein-polymer conjugates as drug delivery system.

    Science.gov (United States)

    Mukherjee, Biswajit; Karmakar, Swapna D; Hossain, Chowdhury M; Bhattacharya, Sanchari

    2014-01-01

    In the last few decades, novel drug delivery strategies have been a big priority to the formulation scientists. Peptides and proteins have drawn a special attention for their wide scope in the area. Serum albumin, transferrin, recom- binant proteins, virus capsids etc. are used as carrier for drug and biomolecules. Conjugates of polymers with proteins have also shown strong potency in the field of drug delivery. Polyethylene glycol is one of the most successful polymers that has been used extensively to develop protein conjugated formulations. Besides, polyvinyl pyrrolidone, polylactic-co- glycolic acid, N-(2-hydroxypropyl) methacrylamide copolymer, polyglutamic acid have also been investigated. In this re- view, we will highlight on the most recent overview of various advantages, limitations and marketed products of proteins, peptides and protein/peptide-polymer conjugates as drug carriers, such products in clinical trials and their various uses in the field of modern drug delivery. Understanding the key features of these materials and the vigorous research in this field will develop new drug formulations that will combat various types of life-threatening diseases.

  19. Synthesis and study of conjugated polymers containing Di- or Triphenylamine

    Energy Technology Data Exchange (ETDEWEB)

    Sukwattanasinitt, M.

    1996-06-21

    This thesis consists of two separate parts. The first part addresses the synthesis and study of conjugated polymers containing di- or triphenylamine. Two types of polymers: linear polymers and dendrimers, were synthesized. The polymers were characterized by NMR, IR, UV, GPC, TGA and DSC. Electronic and optical properties of the polymers were studied through the conductivity measurements and excitation- emission spectra. the second part of this thesis deals with a reaction of electron-rich acetylenes with TCNE. The discovery of the reaction from charge transfer complex studies and the investigation of this reaction on various electron-rich acetylenes are presented.

  20. Thermocleavable π‐Conjugated Polymers – Synthesis and photovoltaic applications

    DEFF Research Database (Denmark)

    Petersen, Martin Helgesen

    Polymer solar cells (plastic solar cells) have seen remarkable improvements in recent years where power conversion efficiencies of up to 6% have been reported for small area devices. However in terms of stability polymer solar cells degrade during illumination and in the dark leading to operational...... lifetimes that are generally very poor. There has been a recent interest in the operational stability of devices and more importantly on the understanding of why devices and materials break down. This has lead to the discovery of a new class of materials that enable exceptionally long device lifetimes...... (>20000 hours). This Ph.D. thesis describes the synthesis, characterization and photovoltaic applications of these novel polymer materials. A key feature of these materials is that solubilizing thermocleavable alkyl ester side chains are introduced on the polymer backbone. The side chains make the polymer...

  1. In situ measurements of the optical absorption of dioxythiophene-based conjugated polymers

    Science.gov (United States)

    Hwang, J.; Schwendeman, I.; Ihas, B. C.; Clark, R. J.; Cornick, M.; Nikolou, M.; Argun, A.; Reynolds, J. R.; Tanner, D. B.

    2011-05-01

    Conjugated polymers can be reversibly doped by electrochemical means. This doping introduces new subband-gap optical absorption bands in the polymer while decreasing the band-gap absorption. To study this behavior, we have prepared an electrochemical cell allowing in situ measurements of the optical properties of the polymer. The cell consists of a thin polymer film deposited on gold-coated Mylar behind which is another polymer that serves as a counterelectrode. An infrared transparent window protects the upper polymer from ambient air. By adding a gel electrolyte and making electrical connections to the polymer-on-gold films, one may study electrochromism in a wide spectral range. As the cell voltage (the potential difference between the two electrodes) changes, the doping level of the conjugated polymer films is changed reversibly. Our experiments address electrochromism in poly(3,4-ethylenedioxythiophene) (PEDOT) and poly(3,4-dimethylpropylenedioxythiophene) (PProDOT-Me2). This closed electrochemical cell allows the study of the doping induced subband-gap features (polaronic and bipolaronic modes) in these easily oxidized and highly redox switchable polymers. We also study the changes in cell spectra as a function of polymer thickness and investigate strategies to obtain cleaner spectra, minimizing the contributions of water and gel electrolyte features.

  2. Time Evolution of the Excimer State of a Conjugated Polymer Laser

    Directory of Open Access Journals (Sweden)

    Wafa Musa Mujamammi

    2017-11-01

    Full Text Available An excited dimer is an important complex formed in nano- or pico-second time scales in many photophysics and photochemistry applications. The spectral and temporal profile of the excimer state of a laser from a new conjugated polymer, namely, poly (9,9-dioctylfluorenyl-2,7-diyl (PFO, under several concentrations in benzene were investigated. These solutions were optically pumped by intense pulsed third-harmonic Nd:YAG laser (355-nm to obtain the amplified spontaneous emission (ASE spectra of a monomer and an excimer with bandwidths of 6 and 7 nm, respectively. The monomer and excimer ASEs were dependent on the PFO concentration, pump power, and temperature. Employing a sophisticated picosecond spectrometer, the time evolution of the excimer state of this polymer, which is over 400 ps, can be monitored.

  3. 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.

  4. Surface and Interface Engineering of Conjugated Polymers and Nanomaterials in Applications of Supercapacitors and Surface-functionalization

    KAUST Repository

    Hou, Yuanfang

    2016-05-23

    In this dissertation, three aspects about surface and interface engineering of conjugated polymers and nanomaterials will be discussed. (i) There is a significant promise for electroactive conjugated polymers (ECPs) in applications of electrochemical devices including energy harvesting, electrochromic displays, etc. Among these, ECPs has also been developed as electroactive materials in electrochemical supercapacitors (ESCs). Compared with metal oxides, ECPs are attractive because they have good intrinsic conductivity, low band-gaps, relatively fast doping-and-undoping process, the ease of synthesis, and tunable electronic and structural properties through structural modifications. Here, Multiple-branch-chain 3,4-ethylenedioxythiophene (EDOT) derivatives was designed as crosslinkers in the co-electropolymerization of EDOT to optimize its morphology and improve the cycling stability of PEDOT in the supercapacitor applications. High-surface-area π-conjugated polymeric networks can be synthesized via the electrochemical copolymerization of the 2D (trivalent) motifs benzo[1,2-b:3,4-b’:5,6-b’’]trithiophene (BTT) and tris-EDOT-benzo[1,2-b:3,4-b’:5,6-b’’]trithiophene (TEBTT) with EDOT. Of all the material systems studied, P(TEBTT/EDOT)-based frameworks achieved the highest areal capacitance with values as high as 443.8 mF cm-2 (at 1 mA cm-2), higher than those achieved by the respective homopolymers (PTEBTT and PEDOT) in the same experimental conditions of electrodeposition (PTEBTT: 271.1 mF cm-2 (at 1 mA cm-2); PEDOT: 12.1 mF cm-2 (at 1 mA cm-2). (ii) In electrochemical process, the suitable choice of appropriate electrolytes to enlarge the safe working potential window with electrolyte stability is well known to improve ECPs’ performance in ESCs applications. Ionic liquids (ILs) are ion-composed salts and usually fluid within a wide temperature range with low melting points. There are many unique characteristics for these intrinsic ion conductors

  5. Vinyl Flanked Difluorobenzothiadiazole-Dithiophene Conjugated Polymer for High Performance Organic Field-Effect Transistors.

    Energy Technology Data Exchange (ETDEWEB)

    Liang, Xianfeng; Sun, Wandong; Chen, Yanlin; Tan, Luxi; Cai, Zheng-Xu; Liu, Zitong; Wang, Lin; Li, Jing; Chen, Wei; Dong, Lichun

    2018-02-21

    Fluorine containing conjugated polymers have been widely applied in high performance organic solar cells, but their use in field-effect transistors is still quite limited. In this work, a conjugated polymer PTFBTV based on difluorobenzothiadiazole (DFBT) and dithiophene was synthesized, utilizing multiple vinylene as linkers. The polymer exhibits a relatively high hole mobility up to 2.0 cm(2) V-1 s(-1) compared with the reported DFBT-oligothiophene based polymers, yet its structural complexity is much simpler. The polymer thin film exhibits a typical 'face on' molecular orientation. A single crystal of its monomer revealed a non-covalent intramolecular contact between fluorine and the neighbouring proton, which strengthens the backbone co-planarity. Meanwhile an intermolecular F...F contact was also observed, which might cause rather scattered lamellar crystallinity for PTFBTV in the solid state.

  6. Conjugated Polymers and Oligomers: Structural and Soft Matter Aspects

    DEFF Research Database (Denmark)

    This book identifies modern topics and current trends of structural and soft matter aspects of conjugated polymers and oligomers. Each chapter recognizes an active research line where structural perspective dominates research and therefore the book covers fundamental aspects of persistent...

  7. Photoinduced FT-IR spectroscopy and CW-photocurrent measurements of conjugated polymers and fullerenes blended into a conventional polymer matrix

    NARCIS (Netherlands)

    Brabec, C.J.; Johannson, H.; Padinger, F.; Neugebauer, H.; Hummelen, J.C.; Sariciftci, N.S.

    2000-01-01

    In this work we present an investigation of the photoexcited states in conjugated polymer (donor) - fullerene (acceptor) interpenetrating networks embedded into conventional polymer hosts like polystyrene (PS), polyvinylcarbazole (PVK) or polyvinylbenzylchloride (PVBC) (guest - host approach), using

  8. Delocalization Drives Free Charge Generation in Conjugated Polymer Films

    Energy Technology Data Exchange (ETDEWEB)

    Rumbles, Garry [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Reid, Obadiah G [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Pace, Natalie A [National Renewable Energy Laboratory (NREL), Golden, CO (United States)

    2018-02-19

    We demonstrate that the product of photoinduced electron transfer between a conjugated polymer host and a dilute molecular sensitizer is controlled by the structural state of the polymer. Ordered semicrystalline solids exhibit free charge generation, while disordered polymers in the melt phase do not. We use photoluminescence (PL) and time-resolved microwave conductivity (TRMC) measurements to sweep through polymer melt transitions in situ. Free charge generation measured by TRMC turns off upon melting, whereas PL quenching of the molecular sensitizers remains constant, implying unchanged electron transfer efficiency. The key difference is the intermolecular order of the polymer host in the solid state compared to the melt. We propose that this order-disorder transition modulates the localization length of the initial charge-transfer state, which controls the probability of free charge formation.

  9. Laterally Ordered Bulk Heterojunction of Conjugated Polymers : Nanoskiving a Jelly Roll

    NARCIS (Netherlands)

    Lipomi, Darren J.; Chiechi, Ryan C.; Reus, William F.; Whitesides, George M.

    2008-01-01

    This paper describes the fabrication of a nanostructured heterojunction of two conjugated polymers by a three-step process: i) spin-coating a multilayered film of the two polymers, ii) rolling the film into a cylinder (a ‘‘jelly roll’’) and iii) sectioning the film perpendicular to the axis of the

  10. Entanglements in Conjugated Polymers

    Science.gov (United States)

    Xie, Renxuan; Lee, Youngmin; Aplan, Melissa; Caggiano, Nick; Gomez, Enrique; Colby, Ralph

    Conjugated polymers, such as poly(3-hexylthiophene-2,5-diyl) (P3HT) and poly-((9,9-dioctylfluorene)-2,7-diyl-alt-[4,7-bis(thiophen-5-yl)-2,1,3-benzothiadiazole]-2',2''-diyl) (PFTBT), are widely used as hole and electron transport materials in a variety of electronic devices. However, fundamental knowledge regarding chain entanglements and nematic-to-isotropic transition is still lacking and are crucial to maximize charge transport properties. A systematic melt rheology study on P3HT with various molecular weights and regio regularities was performed. We find that the entanglement molecular weight Me is 5.0 kg/mol for regiorandom P3HT, but the apparent Me for regioregular P3HT is significantly higher. The difference is postulated to arise from the presence of a nematic phase only in regioregular P3HT. Analogously, PFTBT shows a clear rheological signature of the nematic-to-isotropic transition as a reversible sharp transition at 278 C. Shearing of this nematic phase leads to anisotropic crystalline order in PFTBT. We postulate that aligning the microstructure will impact charge transport and thereby advance the field of conducting polymers. National Science Foundation.

  11. Surface chemistry of photoluminescent F8BT conjugated polymer nanoparticles determines protein corona formation and internalization by phagocytic cells.

    Science.gov (United States)

    Ahmad Khanbeigi, Raha; Abelha, Thais Fedatto; Woods, Arcadia; Rastoin, Olivia; Harvey, Richard D; Jones, Marie-Christine; Forbes, Ben; Green, Mark A; Collins, Helen; Dailey, Lea Ann

    2015-03-09

    Conjugated polymer nanoparticles are being developed for a variety of diagnostic and theranostic applications. The conjugated polymer, F8BT, a polyfluorene derivative, was used as a model system to examine the biological behavior of conjugated polymer nanoparticle formulations stabilized with ionic (sodium dodecyl sulfate; F8BT-SDS; ∼207 nm; -31 mV) and nonionic (pegylated 12-hydroxystearate; F8BT-PEG; ∼175 nm; -5 mV) surfactants, and compared with polystyrene nanoparticles of a similar size (PS200; ∼217 nm; -40 mV). F8BT nanoparticles were as hydrophobic as PS200 (hydrophobic interaction chromatography index value: 0.96) and showed evidence of protein corona formation after incubation with serum-containing medium; however, unlike polystyrene, F8BT nanoparticles did not enrich specific proteins onto the nanoparticle surface. J774A.1 macrophage cells internalized approximately ∼20% and ∼60% of the F8BT-SDS and PS200 delivered dose (calculated by the ISDD model) in serum-supplemented and serum-free conditions, respectively, while cell association of F8BT-PEG was minimal (<5% of the delivered dose). F8BT-PEG, however, was more cytotoxic (IC50 4.5 μg cm(-2)) than F8BT-SDS or PS200. The study results highlight that F8BT surface chemistry influences the composition of the protein corona, while the properties of the conjugated polymer nanoparticle surfactant stabilizer used determine particle internalization and biocompatibility profile.

  12. Real-time observation of conformational switching in single conjugated polymer chains.

    Science.gov (United States)

    Tenopala-Carmona, Francisco; Fronk, Stephanie; Bazan, Guillermo C; Samuel, Ifor D W; Penedo, J Carlos

    2018-02-01

    Conjugated polymers (CPs) are an important class of organic semiconductors that combine novel optoelectronic properties with simple processing from organic solvents. It is important to study CP conformation in solution to understand the physics of these materials and because it affects the properties of solution-processed films. Single-molecule techniques are unique in their ability to extract information on a chain-to-chain basis; however, in the context of CPs, technical challenges have limited their general application to host matrices or semiliquid environments that constrain the conformational dynamics of the polymer. We introduce a conceptually different methodology that enables measurements in organic solvents using the single-end anchoring of polymer chains to avoid diffusion while preserving polymer flexibility. We explore the effect of organic solvents and show that, in addition to chain-to-chain conformational heterogeneity, collapsed and extended polymer segments can coexist within the same chain. The technique enables real-time solvent-exchange measurements, which show that anchored CP chains respond to sudden changes in solvent conditions on a subsecond time scale. Our results give an unprecedented glimpse into the mechanism of solvent-induced reorganization of CPs and can be expected to lead to a new range of techniques to investigate and conformationally manipulate CPs.

  13. In-situ fabrication of diketopyrrolopyrrole-carbazole-based conjugated polymer/TiO2 heterojunction for enhanced visible light photocatalysis

    Science.gov (United States)

    Yang, Long; Yu, Yuyan; Zhang, Jianling; Chen, Fu; Meng, Xiao; Qiu, Yong; Dan, Yi; Jiang, Long

    2018-03-01

    Aiming at developing highly efficient photocatalysts by broadening the light-harvesting region and suppressing photo-generated electron-hole recombination simultaneously, this work reports rational design and fabrication of donor-acceptor (D-A) conjugated polymer/TiO2 heterojunction catalyst with strong interfacial interactions by a facile in-situ thermal treatment. To expand the light-harvesting window, soluable conjugated copolymers with D-A architecture are prepared by Pd-mediated polycondensation of diketopyrrolopyrrole (DPP) and t-butoxycarbonyl (t-Boc) modified carbazole (Car), and used as visible-light-harvesting antenna to couple with TiO2 nanocrystals. The DPP-Car/TiO2 composites show wide range absorption in 300-1000 nm. To improve the interfacial binding at the interface, a facile in-situ thermal treatment is carried out to cleave the pendant t-Boc groups in carbazole units and liberate the polar amino groups (-NH-) which strongly bind to the surface of TiO2 through dipole-dipole interactions, forming a heterojunction interface. This in-situ thermal treatment changes the surface elemental distribution of TiO2, reinforces the interface bonding at the boundary of conjugated polymers/TiO2 and finally improves the photocatalytic efficiency of DPP-Car/TiO2 under visible-light irradiation. The interface changes are characterized and verified through Fourier-transform infrared spectroscopy (FT-IR), photo images, UV/Vis (solution state and powder diffuse reflection spectroscopy), X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS), fluorescence, scanning electron microscopy(SEM) and transmission electron microscopy (TEM) techniques. This study provides a new strategy to avoid the low solubility of D-A conjugated polymers and construct highly-efficient conjugated polymer/TiO2 heterojunction by enforcing the interface contact and facilitating charge or energy transfer for the applications in photocatalysis.

  14. 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.

  15. Synthesis and photocatalytic activity of TiO2/conjugated polymer complex nanoparticles

    Institute of Scientific and Technical Information of China (English)

    Shi Xiong Min; Fang Wang; Lei Feng; Yong Chun Tong; Zi Rong Yang

    2008-01-01

    A photocatalyst of nanometer TiO2/conjugated polymer complex was successfully synthesized and characterized by spectroscopic methods and photocatalytic experiments. The complex photocatalyst could be activated by absorbing both ultraviolet and visible light (λ=190-800nm). Methylene blue (MB) could be degraded more efficiently on the complex photocatalyst than on the TiO2 under natural light. The conjugated polymer played a promoting role in the photocatalytic degradation of MB. The calcination temperature had an important effect in degradation of dye and could be summarized as 260℃>300℃>340℃>220℃>180℃.

  16. Asymmetric diketopyrrolopyrrole conjugated polymers for field-effect transistors and polymer solar cells processed from a non-chlorinated solvent

    NARCIS (Netherlands)

    Ji, Y.; Xiao, C.; Wang, Q.; Zhang, J.; Li, C.; Wu, Y.; Wei, Z.; Zhan, X.; Hu, W.; Wang, Z.; Janssen, R.A.J.; Li, W.W.

    2016-01-01

    Newly designed asymmetric diketopyrrolopyrrole conjugated polymers with two different aromatic substituents possess a hole mobility of 12.5 cm2 V−1 s−1 in field-effect transistors and a power conversion efficiency of 6.5% in polymer solar cells, when solution processed from a nonchlorinated

  17. Photoluminescence quenching through resonant energy transfer in blends of conjugated polymer with low-molecular acceptor

    International Nuclear Information System (INIS)

    Zapunidi, S. A.; Paraschuk, D. Yu.

    2008-01-01

    A model is proposed for photoluminescence quenching due to resonant energy transfer in a blend of a conjugated polymer and a low-molecular energy acceptor. An analytical dependence of the normalized photoluminescence intensity on the acceptor concentration is derived for the case of a homogeneous blend. This dependence can be described by two fitting parameters related to the Foerster radii for energy transfer between conjugated segments of the polymer and between the conjugated polymer segment and the energy acceptor. Asymptotic approximations are obtained for the model dependence that make it possible to estimate the contribution from the spatial migration of excitons to the photoluminescence quenching. The proposed model is used to analyze experimental data on the photoluminescence quenching in a blend of the soluble derivative of poly(p-phenylene vinylene) and trinitrofluorenone [13]. The Foerster radius for resonant energy transfer between the characteristic conjugated segment of poly(p-phenylene vinylene) and the energy acceptor is determined to be r F = 2.6 ± 0.3 nm

  18. A general relationship between disorder, aggregation and charge transport in conjugated polymers

    KAUST Repository

    Noriega, Rodrigo; Rivnay, Jonathan; Vandewal, Koen; Koch, Felix P. V.; Stingelin, Natalie; Smith, Paul; Toney, Michael F.; Salleo, Alberto

    2013-01-01

    Conjugated polymer chains have many degrees of conformational freedom and interact weakly with each other, resulting in complex microstructures in the solid state. Understanding charge transport in such systems, which have amorphous and ordered phases exhibiting varying degrees of order, has proved difficult owing to the contribution of electronic processes at various length scales. The growing technological appeal of these semiconductors makes such fundamental knowledge extremely important for materials and process design. We propose a unified model of how charge carriers travel in conjugated polymer films. We show that in high-molecular-weight semiconducting polymers the limiting charge transport step is trapping caused by lattice disorder, and that short-range intermolecular aggregation is sufficient for efficient long-range charge transport. This generalization explains the seemingly contradicting high performance of recently reported, poorly ordered polymers and suggests molecular design strategies to further improve the performance of future generations of organic electronic materials. © 2013 Macmillan Publishers Limited. All rights reserved.

  19. A general relationship between disorder, aggregation and charge transport in conjugated polymers

    KAUST Repository

    Noriega, Rodrigo

    2013-08-04

    Conjugated polymer chains have many degrees of conformational freedom and interact weakly with each other, resulting in complex microstructures in the solid state. Understanding charge transport in such systems, which have amorphous and ordered phases exhibiting varying degrees of order, has proved difficult owing to the contribution of electronic processes at various length scales. The growing technological appeal of these semiconductors makes such fundamental knowledge extremely important for materials and process design. We propose a unified model of how charge carriers travel in conjugated polymer films. We show that in high-molecular-weight semiconducting polymers the limiting charge transport step is trapping caused by lattice disorder, and that short-range intermolecular aggregation is sufficient for efficient long-range charge transport. This generalization explains the seemingly contradicting high performance of recently reported, poorly ordered polymers and suggests molecular design strategies to further improve the performance of future generations of organic electronic materials. © 2013 Macmillan Publishers Limited. All rights reserved.

  20. Effects of π-conjugation attenuation on the photophysics and exciton dynamics of poly(p-phenylenevinylene) polymers incorporating 2,2'-bipyridines

    International Nuclear Information System (INIS)

    Chen, L. X.; Jager, W. J.; Niemczyk, M. P.; Wasielewski, M. R.

    1999-01-01

    The effect of π-conjugation attenuation on the photophysics and exciton dynamics of two conjugated polymers 1 and 2 are examined in solution. The structures of polymers 1 and 2 have 2,2'-bipyridyl-5-vinylene units that alternate with one and three 2,5-bis(n-decyloxy)-1,4-phenylenevinylene monomer units, respectively. The photophysics and exciton dynamics of polymers 1 and 2 were compared to those of the homopolymer, poly(2,5-bis(2'-ethylhexyloxy)-1,4-phenylenevinylene) (BEH-PPV). A series of changes in the photophysics of polymers 1 and 2 were found as a result of π-conjugation attenuation. These changes include blue shifts in absorption and emission spectra, spectral diffusion in stimulated emission, enhancement in photoluminescence quantum yields and lifetimes, and increases in photoinduced absorption intensities and lifetimes. These changes are systematically more pronounced in polymer 1 than in polymer 2 and are correlated with π-conjugation attenuation in the polymers due to twisting of the 2,2'-bipyridine groups about the 2,2' single bond. An exciton dynamics model involving an ensemble of initial exciton states localized on oligomeric segments within the polymer with different conjugation lengths is proposed to describe the observed differences between polymers 1 and 2 and BEH-PPV. When the electronic coupling between these segments is strong, the polymer displays characteristics that are close to those of a one-dimensional semiconductor. However, when these couplings are weakened by groups, such as the 2,2'-bipyridine that attenuate π-conjugation, the polymer displays properties of an ensemble of oligomers

  1. Emulsion-Based RIR-MAPLE Deposition of Conjugated Polymers: Primary Solvent Effect and Its Implications on Organic Solar Cell Performance.

    Science.gov (United States)

    Ge, Wangyao; Li, Nan K; McCormick, Ryan D; Lichtenberg, Eli; Yingling, Yaroslava G; Stiff-Roberts, Adrienne D

    2016-08-03

    Emulsion-based, resonant infrared matrix-assisted pulsed laser evaporation (RIR-MAPLE) has been demonstrated as an alternative technique to deposit conjugated polymer films for photovoltaic applications; yet, a fundamental understanding of how the emulsion target characteristics translate into film properties and solar cell performance is unclear. Such understanding is crucial to enable the rational improvement of organic solar cell (OSC) efficiency and to realize the expected advantages of emulsion-based RIR-MAPLE for OSC fabrication. In this paper, the effect of the primary solvent used in the emulsion target is studied, both experimentally and theoretically, and it is found to determine the conjugated polymer cluster size in the emulsion as well as surface roughness and internal morphology of resulting polymer films. By using a primary solvent with low solubility-in-water and low vapor pressure, the surface roughness of deposited P3HT and PCPDTBT polymer films was reduced to 10 nm, and the efficiency of P3HT:PC61BM OSCs was increased to 3.2% (∼100 times higher compared to the first MAPLE OSC demonstration [ Caricato , A. P. ; Appl. Phys. Lett. 2012 , 100 , 073306 ]). This work unveils the mechanism of polymer film formation using emulsion-based RIR-MAPLE and provides insight and direction to determine the best ways to take advantage of the emulsion target approach to control film properties for different applications.

  2. Impact of the Crystallite Orientation Distribution on Exciton Transport in Donor–Acceptor Conjugated Polymers

    KAUST Repository

    Ayzner, Alexander L.; Mei, Jianguo; Appleton, Anthony; DeLongchamp, Dean; Nardes, Alexandre; Benight, Stephanie; Kopidakis, Nikos; Toney, Michael F.; Bao, Zhenan

    2015-01-01

    © 2015 American Chemical Society. Conjugated polymers are widely used materials in organic photovoltaic devices. Owing to their extended electronic wave functions, they often form semicrystalline thin films. In this work, we aim to understand whether distribution of crystallographic orientations affects exciton diffusion using a low-band-gap polymer backbone motif that is representative of the donor/acceptor copolymer class. Using the fact that the polymer side chain can tune the dominant crystallographic orientation in the thin film, we have measured the quenching of polymer photoluminescence, and thus the extent of exciton dissociation, as a function of crystal orientation with respect to a quenching substrate. We find that the crystallite orientation distribution has little effect on the average exciton diffusion length. We suggest several possibilities for the lack of correlation between crystallographic texture and exciton transport in semicrystalline conjugated polymer films.

  3. Impact of the Crystallite Orientation Distribution on Exciton Transport in Donor–Acceptor Conjugated Polymers

    KAUST Repository

    Ayzner, Alexander L.

    2015-12-30

    © 2015 American Chemical Society. Conjugated polymers are widely used materials in organic photovoltaic devices. Owing to their extended electronic wave functions, they often form semicrystalline thin films. In this work, we aim to understand whether distribution of crystallographic orientations affects exciton diffusion using a low-band-gap polymer backbone motif that is representative of the donor/acceptor copolymer class. Using the fact that the polymer side chain can tune the dominant crystallographic orientation in the thin film, we have measured the quenching of polymer photoluminescence, and thus the extent of exciton dissociation, as a function of crystal orientation with respect to a quenching substrate. We find that the crystallite orientation distribution has little effect on the average exciton diffusion length. We suggest several possibilities for the lack of correlation between crystallographic texture and exciton transport in semicrystalline conjugated polymer films.

  4. A two-dimensional conjugated aromatic polymer via C-C coupling reaction

    Science.gov (United States)

    Liu, Wei; Luo, Xin; Bao, Yang; Liu, Yan Peng; Ning, Guo-Hong; Abdelwahab, Ibrahim; Li, Linjun; Nai, Chang Tai; Hu, Zhi Gang; Zhao, Dan; Liu, Bin; Quek, Su Ying; Loh, Kian Ping

    2017-06-01

    The fabrication of crystalline 2D conjugated polymers with well-defined repeating units and in-built porosity presents a significant challenge to synthetic chemists. Yet they present an appealing target because of their desirable physical and electronic properties. Here we report the preparation of a 2D conjugated aromatic polymer synthesized via C-C coupling reactions between tetrabromopolyaromatic monomers. Pre-arranged monomers in the bulk crystal undergo C-C coupling driven by endogenous solid-state polymerization to produce a crystalline polymer, which can be mechanically exfoliated into micrometre-sized lamellar sheets with a thickness of 1 nm. Isothermal gas-sorption measurements of the bulk material reveal a dominant pore size of ~0.6 nm, which indicates uniform open channels from the eclipsed stacking of the sheets. When employed as an organic anode in an ambient-temperature sodium cell, the material allows a fast charge/discharge of sodium ions, with impressive reversible capacity, rate capability and stability metrics.

  5. Poly(ethylene glycol-Prodrug Conjugates: Concept, Design, and Applications

    Directory of Open Access Journals (Sweden)

    Shashwat S. Banerjee

    2012-01-01

    Full Text Available Poly(ethylene glycol (PEG is the most widely used polymer in delivering anticancer drugs clinically. PEGylation (i.e., the covalent attachment of PEG of peptides proteins, drugs, and bioactives is known to enhance the aqueous solubility of hydrophobic drugs, prolong circulation time, minimize nonspecific uptake, and achieve specific tumor targetability through the enhanced permeability and retention effect. Numerous PEG-based therapeutics have been developed, and several have received market approval. A vast amount of clinical experience has been gained which has helped to design PEG prodrug conjugates with improved therapeutic efficacy and reduced systemic toxicity. However, more efforts in designing PEG-based prodrug conjugates are anticipated. In light of this, the current paper highlights the synthetic advances in PEG prodrug conjugation methodologies with varied bioactive components of clinical relevance. In addition, this paper discusses FDA-approved PEGylated delivery systems, their intended clinical applications, and formulations under clinical trials.

  6. Rapid, facile synthesis of conjugated polymer zwitterions in ionic liquids

    Energy Technology Data Exchange (ETDEWEB)

    Page, Zachariah A. [Polymer Science & Engineering Department; Conte Center for Polymer Research; University of Massachusetts; Amherst, USA; Liu, Feng [Polymer Science & Engineering Department; Conte Center for Polymer Research; University of Massachusetts; Amherst, USA; Russell, Thomas P. [Polymer Science & Engineering Department; Conte Center for Polymer Research; University of Massachusetts; Amherst, USA; Emrick, Todd [Polymer Science & Engineering Department; Conte Center for Polymer Research; University of Massachusetts; Amherst, USA

    2014-01-01

    Ionic liquids (ILs) were utilized for the rapid air-stable Suzuki polymerization of polar zwitterionic thiophene monomers, precluding the need for volatile organic solvents, phosphine ligands and phase transfer catalysts typically used in conjugated polymer synthesis.

  7. Geometrical relaxation of excitations in one-dimensional conjugated polymers; Giichijigen kyoeki kobunshi reiki jotai no shusa kozo kanwa

    Energy Technology Data Exchange (ETDEWEB)

    Yoshizawa, M. [Tohoku University, Sendai (Japan). Faculty of Engineering

    1995-12-15

    Large ultrafast optical nonlinearities in conjugated polymers have attracted much attention because of possible applications to nonlinear optical devices. One-dimensional systems such as conjugated polymers have localized excited states with geometrical relaxation. In this study, photoexcited states in polydiacetylene has been investigated by femtosecond Raman gain spectroscopy with 300-fs resolution. A new photoinduced Raman peak with lifetime of 1.5 ps has been observed at 1200cm{sup -1} for the first time. This peak indicates acetylene-like structure of the main chain relaxes to butatriene-like structure due to the formation of self-trapped exciting with the geometrical relaxation. The formation and decay kinetics of the Raman signals is consistent with the relaxation processes of exciting observed by femtosecond absorption spectroscopy. 8 refs., 5 figs.

  8. Functional Conducting Polymers in the Application of SPR Biosensors

    Directory of Open Access Journals (Sweden)

    Rapiphun Janmanee

    2012-01-01

    Full Text Available In recent years, conducting polymers have emerged as one of the most promising transducers for both chemical, sensors and biosensors owing to their unique electrical, electrochemical and optical properties that can be used to convert chemical information or biointeractions into electrical or optical signals, which can easily be detected by modern techniques. Different approaches to the application of conducting polymers in chemo- or biosensing applications have been extensively studied. In order to enhance the application of conducting polymers into the area of biosensors, one approach is to introduce functional groups, including carboxylic acid, amine, sulfonate, or thiol groups, into the conducting polymer chain and to form a so-called “self-doped” or by doping with negatively charged polyelectrolytes. The functional conducting polymers have been successfully utilized to immobilize enzymes for construction of biosensors. Recently, the combination of SPR and electrochemical, known as electrochemical-surface plasmon resonance (EC-SPR, spectroscopy, has been used for in situ investigation of optical and electrical properties of conducting polymer films. Moreover, EC-SPR spectroscopy has been applied for monitoring the interaction between biomolecules and electropolymerized conjugated polymer films in biosensor and immunosensor applications. In this paper, recent development and applications on EC-SPR in biosensors will be reviewed.

  9. Solvent-dependent self-assembly and ordering in slow-drying semi-crystalline conjugated polymer solutions

    KAUST Repository

    Zhao, Kui

    2015-09-07

    The mechanistic understanding of the intrinsic molecular self-assembly of conjugated polymers is of immense importance to controlling the microstructure development in organic semiconducting thin films, with meaningful impact on charge transport and optoelectronic properties. Yet, to date the vast majority of studies have focused on the fast solution process itself, with studies of slower intrinsic molecular self-assembly in formulations lagging behind. Here we have investigated molecular self-assembly during spontaneous organization and uncovered how changes in formulation influence the microstructure, morphology and transport properties of conjugated polymer thin films. Our results suggest that the polymer-solvent interaction is the key factor for the molecular self-assembly and changes in macroscopic charge transport, which is in contrast with most solution processes, such as spin-coating and blade coating, where solvent drying kinetics dominates the aggregation and crystallization processes. Energetically favourable interactions between the polymer and its solvent are shown to cause chain expansion, resulting in a large hydrodynamic volume and few chain entanglements in solution. This provides molecular freedom for self-assembly and is shown to greatly enhance the local and long range order of the polymer, intra-chain backbone planarity and crystallite size. These improvements, in turn, are shown to endow the conjugated polymer with high carrier transport, as demonstrated by organic thin film transistors.

  10. Theory of optical transitions in conjugated polymers. I. Ideal systems.

    Science.gov (United States)

    Barford, William; Marcus, Max

    2014-10-28

    We describe a theory of linear optical transitions in conjugated polymers. The theory is based on three assumptions. The first is that the low-lying excited states of conjugated polymers are Frenkel excitons coupled to local normal modes, described by the Frenkel-Holstein model. Second, we assume that the relevant parameter regime is ℏω ≪ J, i.e., the adiabatic regime, and thus the Born-Oppenheimer factorization of the electronic and nuclear degrees of freedom is generally applicable. Finally, we assume that the Condon approximation is valid, i.e., the exciton-polaron wavefunction is essentially independent of the normal modes. Using these assumptions we derive an expression for an effective Huang-Rhys parameter for a chain (or chromophore) of N monomers, given by S(N) = S(1)/IPR, where S(1) is the Huang-Rhys parameter for an isolated monomer. IPR is the inverse participation ratio, defined by IPR = (∑(n)|Ψ(n)|(4))(-1), where Ψ(n) is the exciton center-of-mass wavefunction. Since the IPR is proportional to the spread of the exciton center-of-mass wavefunction, this is a key result, as it shows that S(N) decreases with chain length. As in molecules, in a polymer S(N) has two interpretations. First, ℏωS(N) is the relaxation energy of an excited state caused by its coupling to the normal modes. Second, S(N) appears in the definition of an effective Franck-Condon factor, F(0v)(N) = S(N)(v)exp ( - S(N))/v! for the vth vibronic manifold. We show that the 0 - 0 and 0 - 1 optical intensities are proportional to F00(N) and F01(N), respectively, and thus the ratio of the 0 - 1 to 0 - 0 absorption and emission intensities are proportional to S(N). These analytical results are checked by extensive DMRG calculations and found to be generally valid, particularly for emission. However, for large chain lengths higher-lying quasimomentum exciton states become degenerate with the lowest vibrational excitation of the lowest exciton state. When this happens there is

  11. Hybrid zinc oxide conjugated polymer bulk heterojunction solar cells

    NARCIS (Netherlands)

    Beek, W.J.E.; Wienk, M.M.; Kemerink, M.; Yang, X.N.; Janssen, R.A.J.

    2005-01-01

    Bulk heterojunction photovoltaic devices based on blends of a conjugated polymer poly[2-methoxy-5-(3‘,7‘-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) as electron donor and crystalline ZnO nanoparticles (nc-ZnO) as electron acceptor have been studied. Composite nc-ZnO:MDMO-PPV films were cast

  12. Transmissive-to-black fast electrochromic switching from a long conjugated pendant group and a highly dispersed polymer/SWNT

    KAUST Repository

    Zhang, Qiang

    2018-01-03

    In this study, a novel conjugated polymer, denoted as ECPblack, is synthesized. ECPblack demonstrated a unique electrochromic behavior with an ultrahigh contrast ratio (over 80%) in most of the visible regions, boasting an ultrahigh integrated contrast ratio of 71.8% between 380 nm and 880 nm. The long conjugated pendant group (pyrene) in ECPblack enhances the absorption in the blue region in its second oxidized state and results in transmissive-to-black electrochromic switching between the neutral state and the oxidized state. The transmissive-to-black electrochromic switching polymer with an ultrahigh contrast ratio could be especially attractive for applications in electronic displays. In addition, when polytriarylamine/nanotube (SWNT/P2) dispersion is doped in ECPblack, the response time of its electrochemical and electrochromic behaviors is further reduced. The electrochromic switching and bleaching time of SWNT/P2/ECPblack decreased by 73% and 80%, respectively. The improvement is caused by the phase separation of the rigid SWNT and the flexible polymer, which generates a rough surface morphology and provides more pathways for faster diffusion of counterions (ClO4-). The polymer/SWNT doping technique provides a simple way to accelerate ion diffusion in anodically coloring materials.

  13. Transmissive-to-black fast electrochromic switching from a long conjugated pendant group and a highly dispersed polymer/SWNT

    KAUST Repository

    Zhang, Qiang; Tsai, Chou-Yi; Abidin, Taufik; Jiang, Jyh-Chiang; Shie, Wan-Ru; Li, Lain-Jong; Liaw, Der-Jang

    2018-01-01

    In this study, a novel conjugated polymer, denoted as ECPblack, is synthesized. ECPblack demonstrated a unique electrochromic behavior with an ultrahigh contrast ratio (over 80%) in most of the visible regions, boasting an ultrahigh integrated contrast ratio of 71.8% between 380 nm and 880 nm. The long conjugated pendant group (pyrene) in ECPblack enhances the absorption in the blue region in its second oxidized state and results in transmissive-to-black electrochromic switching between the neutral state and the oxidized state. The transmissive-to-black electrochromic switching polymer with an ultrahigh contrast ratio could be especially attractive for applications in electronic displays. In addition, when polytriarylamine/nanotube (SWNT/P2) dispersion is doped in ECPblack, the response time of its electrochemical and electrochromic behaviors is further reduced. The electrochromic switching and bleaching time of SWNT/P2/ECPblack decreased by 73% and 80%, respectively. The improvement is caused by the phase separation of the rigid SWNT and the flexible polymer, which generates a rough surface morphology and provides more pathways for faster diffusion of counterions (ClO4-). The polymer/SWNT doping technique provides a simple way to accelerate ion diffusion in anodically coloring materials.

  14. Improving the in vivo therapeutic index of siRNA polymer conjugates through increasing pH responsiveness.

    Science.gov (United States)

    Guidry, Erin N; Farand, Julie; Soheili, Arash; Parish, Craig A; Kevin, Nancy J; Pipik, Brenda; Calati, Kathleen B; Ikemoto, Nori; Waldman, Jacob H; Latham, Andrew H; Howell, Bonnie J; Leone, Anthony; Garbaccio, Robert M; Barrett, Stephanie E; Parmar, Rubina Giare; Truong, Quang T; Mao, Bing; Davies, Ian W; Colletti, Steven L; Sepp-Lorenzino, Laura

    2014-02-19

    Polymer based carriers that aid in endosomal escape have proven to be efficacious siRNA delivery agents in vitro and in vivo; however, most suffer from cytotoxicity due in part to a lack of selectivity for endosomal versus cell membrane lysis. For polymer based carriers to move beyond the laboratory and into the clinic, it is critical to find carriers that are not only efficacious, but also have margins that are clinically relevant. In this paper we report three distinct categories of polymer conjugates that improve the selectivity of endosomal membrane lysis by relying on the change in pH associated with endosomal trafficking, including incorporation of low pKa heterocycles, acid cleavable amino side chains, or carboxylic acid pH sensitive charge switches. Additionally, we determine the therapeutic index of our polymer conjugates in vivo and demonstrate that the incorporation of pH responsive elements dramatically expands the therapeutic index to 10-15, beyond that of the therapeutic index (less than 3), for polymer conjugates previously reported.

  15. Effect of disorder on exciton dissociation in conjugated polymers

    International Nuclear Information System (INIS)

    Feng Yuwen; Zhao Hui; Chen Yuguang; Yan Yonghong

    2017-01-01

    By using a multi-configurational time-dependent Hartree–Fock (MCTDHF) method for the time-dependent Schrödinger equation and a Newtonian equation of motion for lattice, we investigate the disorder effects on the dissociation process of excitons in conjugated polymer chains. The simulations are performed within the framework of an extended version of the Su–Schrieffer–Heeger model modified to include on-site disorder, off-diagonal, electron–electron interaction, and an external electric field. Our results show that Coulomb correlation effects play an important role in determining the exciton dissociation process. The electric field required to dissociate an exciton can practically impossibly occur in a pure polymer chain, especially in the case of triplet exciton. However, when the on-site disorder effects are taken into account, this leads to a reduction in mean dissociation electric fields. As the disorder strength increases, the dissociation field decreases effectively. On the contrary, the effects of off-diagonal disorder are negative in most cases. Moreover, the dependence of exciton dissociation on the conjugated length is also discussed. (paper)

  16. The optical and electrical properties of graphene oxide with water-soluble conjugated polymer composites by radiation.

    Science.gov (United States)

    Jungo, Seung Tae; Oh, Seung-Hwan; Kim, Hyun Bin; Jeun, Joon-Pyo; Lee, Bum-Jae; Kang, Phil-Hyun

    2013-11-01

    In order to overcome the difficulty of dispersion and low conductivity in composite containing graphene, graphene oxide (GO) has been used instead of neat graphene. And the GO treated by radiation, could give improved conductivity of the GO-containing polymer composite. In this study, fluorene based water-soluble conjugated polymer (WPF-6-oxy-F) was introduced in GO solution to investigate the change of optical and electrical properties through radiation process. UV-Vis absorption of irradiated WPF-6-oxy-F-GO composite was red shifted and I(D)/I(G) ratio of Raman spectra decreased. XPS analysis showed that C-N bonds was formed after the irradiation and confirmed the increased bonds between the GO and the water-soluble conjugated polymer matrix. From the AFM and XPS analysis, it was found that the water-soluble conjugated polymer matrix was stacked between the modified GO in the morphology of irradiated WPF-6-oxy-F-GO composite was increased after gamma ray irradiation up to 10(-2) S/cm.

  17. BRCAA1 antibody- and Her2 antibody-conjugated amphiphilic polymer engineered CdSe/ZnS quantum dots for targeted imaging of gastric cancer

    Science.gov (United States)

    Li, Chao; Ji, Yang; Wang, Can; Liang, Shujing; Pan, Fei; Zhang, Chunlei; Chen, Feng; Fu, Hualin; Wang, Kan; Cui, Daxiang

    2014-05-01

    Successful development of safe and highly effective nanoprobes for targeted imaging of in vivo early gastric cancer is a great challenge. Herein, we choose the CdSe/ZnS (core-shell) quantum dots (QDs) as prototypical materials, synthesized one kind of a new amphiphilic polymer including dentate-like alkyl chains and multiple carboxyl groups, and then used the prepared amphiphilic polymer to modify QDs. The resultant amphiphilic polymer engineered QDs (PQDs) were conjugated with BRCAA1 and Her2 monoclonal antibody, and prepared BRCAA1 antibody- and Her2 antibody-conjugated QDs were used for in vitro MGC803 cell labeling and in vivo targeted imaging of gastric cancer cells. Results showed that the PQDs exhibited good water solubility, strong photoluminescence (PL) intensity, and good biocompatibility. BRCAA1 antibody- and Her2 antibody-conjugated QD nanoprobes successfully realized targeted imaging of in vivo gastric cancer MGC803 cells. In conclusion, BRCAA1 antibody- and Her2 antibody-conjugated PQDs have great potential in applications such as single cell labeling and in vivo tracking, and targeted imaging and therapeutic effects' evaluation of in vivo early gastric cancer cells in the near future.

  18. Impact of morphology on polaron delocalization in a semicrystalline conjugated polymer

    KAUST Repository

    Steyrleuthner, Robert; Zhang, Yuexing; Zhang, Lei; Kraffert, Felix; Cherniawski, Benjamin P.; Bittl, Robert; Briseno, Alejandro L.; Bredas, Jean-Luc; Behrends, Jan

    2016-01-01

    We investigate the delocalization of holes in the semicrystalline conjugated polymer poly(2,5-bis(3-alkylthiophene-2-yl)thieno[3,2-b]thiophene) (PBTTT) by directly measuring the hyperfine coupling between photogenerated polarons and bound nuclear

  19. Photovoltaic properties of conjugated polymer/fullerene composites on large area flexible substrates

    Directory of Open Access Journals (Sweden)

    Desta Gebeyehu

    2000-06-01

    Full Text Available In this paper we present measurements of the photovoltaic response of bulk donor-acceptor heterojunction between the conjugated polymer, poly(3-octylthiophene, P3OT, (as a donor, D and fullerene (methanofullerene, (as acceptor, A, deposited between indium tin oxide and aluminum electrodes. The innovation involves the substrate, which is a polymer foil instead of glass. These devices are based on ultrafast, reversible, metastable photoinduced electron transfer and charge separation. We also present the efficiency and stability studies on large area (6 cm x 6 cm flexible plastic solar cells with monochromatic energy conversion efficiency (e of about 1.5% and carrier collection efficiency of nearly 20%. Further more, we have investigated the surface network morphology of these films layers by atomic force microscope (AFM. The development of solar cells based on composites of organic conjugated semi-conducting polymers with fullerene derivatives can provide a new method in the exploitation of solar energy.

  20. Ultrafast intersystem-crossing in platinum containing π-conjugated polymers with tunable spin-orbit coupling.

    Science.gov (United States)

    Sheng, C-X; Singh, S; Gambetta, A; Drori, T; Tong, M; Tretiak, S; Vardeny, Z V

    2013-01-01

    The development of efficient organic light-emitting diodes (OLED) and organic photovoltaic cells requires control over the dynamics of spin sensitive excitations. Embedding heavy metal atoms in π-conjugated polymer chains enhances the spin-orbit coupling (SOC), and thus facilitates intersystem crossing (ISC) from the singlet to triplet manifolds. Here we use various nonlinear optical spectroscopies such as two-photon absorption and electroabsorption in conjunction with electronic structure calculations, for studying the energies, emission bands and ultrafast dynamics of spin photoexcitations in two newly synthesized π-conjugated polymers that contain intrachain platinum (Pt) atoms separated by one (Pt-1) or three (Pt-3) organic spacer units. The controllable SOC in these polymers leads to a record ISC time of white OLEDs.

  1. Ultrafast photophysics of pi-conjugated polymers for organic light emitting diode applications

    Science.gov (United States)

    Olejnik, Ella

    In this work we used the pump-probe photomodulation (PM) spectroscopy technique to measure the transient PM spectrum and decay kinetics in various pi -- conjugated polymers (PCPs) films and blends. Using two ultrafast laser systems, we covered a broad spectral range from 0.25 -- 2.5 eV in the time domain from 200 fs to 1 ns with 150 fs time resolution. We also used continuous wave (CW) photomodulation spectroscopy, photoluminescence (PL), electro-absorption and doping-induced absorption to study the photoexcitations and other optical properties of PCPs and guest/ host blends. In particular we studied two different types of Poly(thienylenevinylene) polymer derivatives. One polymer type is the ordered regio-regular (RR) and regio-random (RRa) -- PTV in which the dark exciton, 2Ag is the lowest excited state. In these polymers the photoexcited exciton shows very fast decay kinetics due to the internal conversion to the dark exciton, which results in weak PL emission; thus these two polymers are non-luminescent. The other PTV derivative is the imide -- PTV which is more luminescent due to the proximity of 1Bu and 2Ag states, that results in longer decay kinetics and a difference between the calculated value of the QEPL (9%) and the measured one (1%). We also demonstrate transient strain spectroscopy in RR -- PTV thin films, where the ultrafast energy release associated with the exciton decay gives rise to substantial static and dynamic strains in the film that dramatically influences the film's transient PM response. We also study the photophysics of poly(dioctyloxy) phenylenevinylene polymer with different isotopes, where we substituted hydrogen (H-polymer) by deuterium (D-polymer), and 12C by 13C isotopes. From the transient decay kinetics measurements we found that the exciton recombination in DOO -- PPV consists of two processes. These are: intrinsic monomolecular, and exciton-exciton annihilation (bimolecular). In the D -- polymer, different probe frequencies of

  2. First-principles calculation of optical absorption spectra in conjugated polymers: Role of electron-hole interaction

    International Nuclear Information System (INIS)

    Rohlfing, Michael; Tiago, M.L.; Louie, Steven G.

    2000-01-01

    Experimental and theoretical studies have shown that excitonic effects play an important role in the optical properties of conjugated polymers. The optical absorption spectrum of trans-polyacetylene, for example, can be understood as completely dominated by the formation of exciton bound states. We review a recently developed first-principles method for computing the excitonic effects and optical spectrum, with no adjustable parameters. This theory is used to study the absorption spectrum of two conjugated polymers: trans-polyacetylene and poly-phenylene-vinylene(PPV)

  3. First-principles calculation of optical absorption spectra in conjugated polymers: Role of electron-hole interaction

    Energy Technology Data Exchange (ETDEWEB)

    Rohlfing, Michael; Tiago, M.L.; Louie, Steven G.

    2000-03-20

    Experimental and theoretical studies have shown that excitonic effects play an important role in the optical properties of conjugated polymers. The optical absorption spectrum of trans-polyacetylene, for example, can be understood as completely dominated by the formation of exciton bound states. We review a recently developed first-principles method for computing the excitonic effects and optical spectrum, with no adjustable parameters. This theory is used to study the absorption spectrum of two conjugated polymers: trans-polyacetylene and poly-phenylene-vinylene(PPV).

  4. Direct measurement of the microscale conductivity of conjugated polymer monolayers

    DEFF Research Database (Denmark)

    Bøggild, Peter; Grey, Francois; Hassenkam, T.

    2000-01-01

    The in-plane conductivity of conjugated polymer monolayers is mapped here for the first time on the microscale using a novel scanning micro four-point probe (see Figure). The probe allows the source, drain, and voltage electrodes to be positioned within the same domain and the mapping results...

  5. Dye sensitized photovoltaic cells: Attaching conjugated polymers to zwitterionic ruthenium dyes

    DEFF Research Database (Denmark)

    Krebs, Frederik C; Biancardo, M.

    2006-01-01

    The synthesis of a zwitterionic ruthenium dye that binds to anatase surfaces and has a built-in functionality that allows for the attachment of a conjugated polymer chain is presented. The system was found to adsorb on the surface of anatase anchored by the ruthenium dye. Two types of devices were...... prepared: standard photoelectrochemical (PEC) solar cells and polymer solar cells. The PEC solar cells employed a sandwich geometry between TiO2 nanoporous photoanodes and Pt counter electrodes using LiI/I-2 in CH3CN as an electrolyte. The polymer solar cells employed planar anatase electrodes...

  6. The Curious Case of Fluorination of Conjugated Polymers for Solar Cells.

    Science.gov (United States)

    Zhang, Qianqian; Kelly, Mary Allison; Bauer, Nicole; You, Wei

    2017-09-19

    Organic solar cells (OSCs) have been a rising star in the field of renewable energy since the introduction of the bulk heterojunction (BHJ) in 1992. Recent advances have pushed the efficiencies of OSCs to over 13%, an impressive accomplishment via collaborative efforts in rational materials design and synthesis, careful device engineering, and fundamental understanding of device physics. Throughout these endeavors, several design principles for the conjugated donor polymers used in such solar cells have emerged, including optimizing the conjugated backbone with judicious selection of building blocks, side-chain engineering, and substituents. Among all of the substituents, fluorine is probably the most popular one; improved device characteristics with fluorination have frequently been reported for a wide range of conjugated polymers, in particular, donor-acceptor (D-A)-type polymers. Herein we examine the effect of fluorination on the device performance of solar cells as a function of the position of fluorination (on the acceptor unit or on the donor unit), aiming to outline a clear understanding of the benefits of this curious substituent. As fluorination of the acceptor unit is the most adopted strategy for D-A polymers, we first discuss the effect of fluorination of the acceptor units, highlighting the five most widely utilized acceptor units. While improved device efficiency has been widely observed with fluorinated acceptor units, the underlying reasons vary from case to case and highly depend on the chemical structure of the polymer. Second, the effect of fluorination of the donor unit is addressed. Here we focus on four donor units that have been most studied with fluorination. While device-performance-enhancing effects by fluorination of the donor units have also been observed, it is less clear that fluorine will always benefit the efficiency of the OSC, as there are several cases where the efficiency drops, in particular with "over-fluorination", i.e., when

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

    International Nuclear Information System (INIS)

    Matterson, B.J.

    2002-03-01

    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 found that the photoluminescence quantum yield of a film spun onto a substrate inscribed with a grating is increased. It is also found that the photoluminescence spectrum of the film is dramatically altered and varies substantially with viewing angle. The features in the spectrum caused by the grating are strongly polarized. These effects are analysed and are attributed to the scattering of waveguided light out of the film. It is found that films spun onto metal gratings exhibit especially strong scattering. The effect of metal gratings with various grating depths is analysed. The possible contribution of band gaps to the photoluminescence spectrum from polymers on strong metal gratings is discussed. LEDs that include grating structures are constructed and analysed. It is found that having grating structures on the 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. (author)

  8. Study of a thiophene-based polymer for optoelectronic applications

    International Nuclear Information System (INIS)

    Cheylan, S.; Fraleoni-Morgera, A.; Puigdollers, J.; Voz, C.; Setti, L.; Alcubilla, R.; Badenes, G.; Costa-Bizzarri, P.; Lanzi, M.

    2006-01-01

    A thiophene-based conjugated polymer bearing a cyano group (-CN) as a side chain substituent was successfully synthesized. The polymer evidences an excellent film ability from various organic solvents as well as an enhanced photoluminescence. The polymer has been characterized optically (Fourier Transformed Infrared spectroscopy, absorption and photoluminescence) in solution and in film, while X-ray diffraction measurements (XRD) of thin films were performed to investigate its bulk morphological features. From the absorption edge of the spectrum of a thin polymer film, the optical band gap of the polymer is estimated to be 2.0 eV, which corresponds to orange emission. Furthermore, a single layer light emitting diode (LED) was fabricated. The device produced bright stable electroluminescence at room temperature. All of the results indicate that this polymer is a promising emissive material for application in polymeric LEDs

  9. Conducting polymers, buckminsterfullerenes, and carbon nanotubes: optoelectronic materials based on architectural diversity of the π-conjugated structure

    International Nuclear Information System (INIS)

    Dai, L.

    2001-01-01

    Recent discovery of superconductivity in self assembled poly(3-hexylthiophene) two-dimensional conjugated sheets indicates the possible applications of plastics even in superconducting optoelectronic devices. Just as the discovery of C 60 has created an entirely new branch of carbon chemistry, the subsequent discovery of carbon nanotubes by lijima in 1991 opened up a new era in material science and nanotechnology. These elongated nanotubes consist of carbon hexagons arranged in a concentric manner with both ends normally capped by fullerene-like structures containing pentagons. Having a conjugated all-carbon structure with unusual molecular symmetries, fullerenes and carbon nanotubes also show interesting electronic, photonic, magnetic and mechanical properties, attractive for various applications, including optical limiters, photovoltaic cells and field emitting displays. For most of the above applications, it is highly desirable to prepare ordered/micropatterned conducting polymers, fullerenes, and carbon nanotubes. Although the microfabrication of conducting polymers has been an active research area for some years, it is a very recent development for fullerenes and carbon nanotubes. Recently, we doped polyaniline (PANI) with a hydrogensulfated fullerenol derivative containing multiple -OSO 3 H groups (i.e. C 60 (OH) 6 (OSO 3 H) 6 ) to produce three-dimensional PANI conductors with a room-temperature conductivity of up to 100 S cm -1 . This value of conductivity is about six orders of magnitude higher than the typical value for C 60 doped conducting polymers. Later, in collaboration with Wan's group at the Chinese Academy of Sciences, we have also synthesized PANI nanotubes via a self assembled C 60 (OH) 6 (OSO 3 H) 6 supramolecular template using (NH 4 ) 2 S 2 O 8 as an oxidant. These results, together with the more recent discovery of a hollow sphere, self assembled by the potassium salt of pentaphenyl fullerene (Ph 5 C 60 K) in water, clearly indicate that

  10. Hydrophilic Conjugated Polymers with Large Bandgaps and Deep-Lying HOMO Levels as an Efficient Cathode Interlayer in Inverted Polymer Solar Cells.

    Science.gov (United States)

    Kan, Yuanyuan; Zhu, Yongxiang; Liu, Zhulin; Zhang, Lianjie; Chen, Junwu; Cao, Yong

    2015-08-01

    Two hydrophilic conjugated polymers, PmP-NOH and PmP36F-NOH, with polar diethanol-amine on the side chains and main chain structures of poly(meta-phenylene) and poly(meta-phenylene-alt-3,6-fluorene), respectively, are successfully synthesized. The films of PmP-NOH and PmP36F-NOH show absorption edges at 340 and 343 nm, respectively. The calculated optical bandgaps of the two polymers are 3.65 and 3.62 eV, respectively, the largest ones so far reported for hydrophilic conjugated polymers. PmP-NOH and PmP36F-NOH also possess deep-lying highest occupied molecular orbital levels of -6.19 and -6.15 eV, respectively. Inserting PmP-NOH and PmP36F-NOH as a cathode interlayer in inverted polymer solar cells with a PTB7/PC71 BM blend as the active layer, high power conversion efficiencies of 8.58% and 8.33%, respectively, are achieved, demonstrating that the two hydrophilic polymers are excellent interlayers for efficient inverted polymer solar cells. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Distinct Interfacial Fluorescence in Oil-in-Water Emulsions via Exciton Migration of Conjugated Polymers.

    Science.gov (United States)

    Koo, Byungjin; Swager, Timothy M

    2017-09-01

    Commercial dyes are extensively utilized to stain specific phases for the visualization applications in emulsions and bioimaging. In general, dyes emit only one specific fluorescence signal and thus, in order to stain various phases and/or interfaces, one needs to incorporate multiple dyes and carefully consider their compatibility to avoid undesirable interactions with each other and with the components in the system. Herein, surfactant-type, perylene-endcapped fluorescent conjugated polymers that exhibit two different emissions are reported, which are cyan in water and red at oil-water interfaces. The interfacially distinct red emission results from enhanced exciton migration from the higher-bandgap polymer backbone to the lower-bandgap perylene endgroup. The confocal microscopy images exhibit the localized red emission exclusively from the circumference of oil droplets. This exciton migration and dual fluorescence of the polymers in different physical environments can provide a new concept of visualization methods in many amphiphilic colloidal systems and bioimaging. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Molecular-weight dependence of interchain polaron delocalization and exciton bandwidth in high-mobility conjugated polymers

    DEFF Research Database (Denmark)

    Chang, J.F.; Clark, J.; Zhao, N.

    2006-01-01

    delocalization with increasing conjugation length and crystalline quality. From comparative studies of field-effect transistor characteristics, film morphology, and optical properties our study provides a microscopic understanding of the factors which limit the charge transport in P3HT to field-effect mobilities......Interchain interactions have a profound effect on the optical as well as charge transport properties of conjugated polymer thin films. In contrast to oligomeric model systems in solution-deposited polymer thin films the study of such effects is complicated by the complex microstructure. We present...

  13. New electroluminescent carbazole-containing conjugated polymer: synthesis, photophysics, and electroluminescence

    Czech Academy of Sciences Publication Activity Database

    Cimrová, Věra; Ulbricht, C.; Dzhabarov, Vagif; Výprachtický, Drahomír; Egbe, D. A. M.

    2014-01-01

    Roč. 55, č. 24 (2014), s. 6220-6226 ISSN 0032-3861 R&D Projects: GA ČR GAP106/12/0827; GA ČR(CZ) GA13-26542S Institutional support: RVO:61389013 Keywords : carbazole-containing conjugated polymer * synthesis * photophysics and electroluminescence Subject RIV: CD - Macromolecular Chemistry Impact factor: 3.562, year: 2014

  14. Bio-Conjugates for Nanoscale Applications

    DEFF Research Database (Denmark)

    Villadsen, Klaus

    Bio-conjugates for Nanoscale Applications is the title of this thesis, which covers three different projects in chemical bio-conjugation research, namely synthesis and applications of: Lipidated fluorescent peptides, carbohydrate oxime-azide linkers and N-aryl O-R2 oxyamine derivatives. Lipidated...

  15. Comparison of eosin and fluorescein conjugates for the photoinitiation of cell-compatible polymer coatings.

    Directory of Open Access Journals (Sweden)

    Jacob L Lilly

    Full Text Available Targeted photopolymerization is the basis for multiple diagnostic and cell encapsulation technologies. While eosin is used in conjunction with tertiary amines as a water-soluble photoinitiation system, eosin is not widely sold as a conjugate with antibodies and other targeting biomolecules. Here we evaluate the utility of fluorescein-labeled bioconjugates to photopolymerize targeted coatings on live cells. We show that although fluorescein conjugates absorb approximately 50% less light energy than eosin in matched photopolymerization experiments using a 530 nm LED lamp, appreciable polymer thicknesses can still be formed in cell compatible environments with fluorescein photosensitization. At low photoinitiator density, eosin allows more sensitive initiation of gelation. However at higher functionalization densities, the thickness of fluorescein polymer films begins to rival that of eosin. Commercial fluorescein-conjugated antibodies are also capable of generating conformal, protective coatings on mammalian cells with similar viability and encapsulation efficiency as eosin systems.

  16. Comparison of eosin and fluorescein conjugates for the photoinitiation of cell-compatible polymer coatings.

    Science.gov (United States)

    Lilly, Jacob L; Gottipati, Anuhya; Cahall, Calvin F; Agoub, Mohamed; Berron, Brad J

    2018-01-01

    Targeted photopolymerization is the basis for multiple diagnostic and cell encapsulation technologies. While eosin is used in conjunction with tertiary amines as a water-soluble photoinitiation system, eosin is not widely sold as a conjugate with antibodies and other targeting biomolecules. Here we evaluate the utility of fluorescein-labeled bioconjugates to photopolymerize targeted coatings on live cells. We show that although fluorescein conjugates absorb approximately 50% less light energy than eosin in matched photopolymerization experiments using a 530 nm LED lamp, appreciable polymer thicknesses can still be formed in cell compatible environments with fluorescein photosensitization. At low photoinitiator density, eosin allows more sensitive initiation of gelation. However at higher functionalization densities, the thickness of fluorescein polymer films begins to rival that of eosin. Commercial fluorescein-conjugated antibodies are also capable of generating conformal, protective coatings on mammalian cells with similar viability and encapsulation efficiency as eosin systems.

  17. Bulk Heterojunction Solar Cells Based on Blends of Conjugated Polymers with II–VI and IV–VI Inorganic Semiconductor Quantum Dots

    Directory of Open Access Journals (Sweden)

    Ryan Kisslinger

    2017-01-01

    Full Text Available Bulk heterojunction solar cells based on blends of quantum dots and conjugated polymers are a promising configuration for obtaining high-efficiency, cheaply fabricated solution-processed photovoltaic devices. Such devices are of significant interest as they have the potential to leverage the advantages of both types of materials, such as the high mobility, band gap tunability and possibility of multiple exciton generation in quantum dots together with the high mechanical flexibility and large molar extinction coefficient of conjugated polymers. Despite these advantages, the power conversion efficiency (PCE of these hybrid devices has remained relatively low at around 6%, well behind that of all-organic or all-inorganic solar cells. This is attributed to major challenges that still need to be overcome before conjugated polymer–quantum dot blends can be considered viable for commercial application, such as controlling the film morphology and interfacial structure to ensure efficient charge transfer and charge transport. In this work, we present our findings with respect to the recent development of bulk heterojunctions made from conjugated polymer–quantum dot blends, list the ongoing strategies being attempted to improve performance, and highlight the key areas of research that need to be pursued to further develop this technology.

  18. Planar conjugated polymers containing 9,10-disubstituted phenanthrene units for efficient polymer solar cells.

    Science.gov (United States)

    Li, Guangwu; Kang, Chong; Li, Cuihong; Lu, Zhen; Zhang, Jicheng; Gong, Xue; Zhao, Guangyao; Dong, Huanli; Hu, Wenping; Bo, Zhishan

    2014-06-01

    Four novel conjugated polymers (P1-4) with 9,10-disubstituted phenanthrene (PhA) as the donor unit and 5,6-bis(octyloxy)benzothiadiazole as the acceptor unit are synthesized and characterized. These polymers are of medium bandgaps (2.0 eV), low-lying HOMO energy levels (below -5.3 eV), and high hole mobilities (in the range of 3.6 × 10(-3) to 0.02 cm(2) V(-1) s(-1) ). Bulk heterojunction (BHJ) polymer solar cells (PSCs) with P1-4:PC71 BM blends as the active layer and an alcohol-soluble fullerene derivative (FN-C60) as the interfacial layer between the active layer and cathode give the best power conversion efficiency (PCE) of 4.24%, indicating that 9,10-disubstituted PhA are potential donor materials for high-efficiency BHJ PSCs. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Adaptive sliding mode control of tri-layer conjugated polymer actuators

    International Nuclear Information System (INIS)

    Wang, Xiangjiang; Alici, Gursel; Nguyen, Chuc Huu

    2013-01-01

    This paper proposes an adaptive sliding mode control methodology to enhance the positioning ability of conducting polymer actuators typified by tri-layer conjugated polymer actuators. This is motivated by the search for an effective control strategy to command such actuators to a desired configuration in the presence of parametric uncertainties and unmodeled disturbances. After analyzing the stability of the adaptive sliding mode control system, experiments were conducted to demonstrate its satisfactory tracking ability, based on a series of experimental results. Implementation of the control law requires a valid model of the conducting polymer actuator and boundaries of the uncertainties and disturbances. Based on the theoretical and experimental results presented, the adaptive sliding mode control methodology is very attractive in the field of smart actuators which contain significant uncertainties and disturbances. (paper)

  20. Bispecific antibody complex pre-targeting and targeted delivery of polymer drug conjugates for imaging and therapy in dual human mammary cancer xenografts. Targeted polymer drug conjugates for cancer diagnosis and therapy

    Energy Technology Data Exchange (ETDEWEB)

    Khaw, Ban-An; Gada, Keyur S.; Patil, Vishwesh; Panwar, Rajiv; Mandapati, Savitri [Northeastern University, Department of Pharmaceutical Sciences, Bouve College of Health Sciences, School of Pharmacy, Boston, MA (United States); Hatefi, Arash [Rutgers University, Department of Pharmaceutics, New Brunswick, NJ (United States); Majewski, Stan [West Virginia University, Department of Radiology, Morgantown, WV (United States); Weisenberger, Andrew [Thomas Jefferson National Accelerator Facility, Jefferson Lab, Newport News, VA (United States)

    2014-08-15

    Doxorubicin, a frontline chemotherapeutic agent, limited by its cardiotoxicity and other tissue toxicities, was conjugated to N-terminal DTPA-modified polyglutamic acid (D-Dox-PGA) to produce polymer pro-drug conjugates. D-Dox-PGA or Tc-99 m labeled DTPA-succinyl-polylysine polymers (DSPL) were targeted to HER2-positive human mammary carcinoma (BT-474) in a double xenografted SCID mouse model also hosting HER2-negative human mammary carcinoma (BT-20). After pretargeting with bispecific anti-HER2-affibody-anti-DTPA-Fab complexes (BAAC), anti-DTPA-Fab or only phosphate buffered saline, D-Dox-PGA or Tc-99 m DSPL were administered. Positive therapeutic control mice were injected with Dox alone at maximum tolerated dose (MTD). Only BT-474 lesions were visualized by gamma imaging with Tc-99 m-DSPL; BT-20 lesions were not. Therapeutic efficacy was equivalent in mice pretargeted with BAAC/targeted with D-Dox-PGA to mice treated only with doxorubicin. There was no total body weight (TBW) loss at three times the doxorubicin equivalent MTD with D-Dox-PGA, whereas mice treated with doxorubicin lost 10 % of TBW at 2 weeks and 16 % after the second MTD injection leading to death of all mice. Our cancer imaging and pretargeted therapeutic approaches are highly target specific, delivering very high specific activity reagents that may result in the development of a novel theranostic application. HER/2 neu specific affibody-anti-DTPA-Fab bispecific antibody pretargeting of HER2 positive human mammary xenografts enabled exquisite targeting of polymers loaded with radioisotopes for molecular imaging and doxorubicin for effective therapy without the associating non-tumor normal tissue toxicities. (orig.)

  1. Electro-Optical and Electrochemical Properties of a Conjugated Polymer Prepared by the Cyclopolymerization of Diethyl Dipropargylmalonate

    Directory of Open Access Journals (Sweden)

    Yeong-Soon Gal

    2008-01-01

    Full Text Available The electro-optical and electrochemical properties of poly(diethyl dipropargylmalonate were measured and discussed. Poly(diethyl dipropargylmalonate prepared by (NBDPdCl2 catalyst was used for study. The chemical structure of poly(diethyl dipropargylmalonate was characterized by such instrumental methods as NMR (1H-, 13C-, IR, and UV-visible spectroscopies to have the conjugated cyclopolymer backbone system. The microstructure analysis of polymer revealed that this polymer have the six-membered ring moieties majorly. The photoluminescence peak of polymer was observed at 543 nm, which is corresponded to the photon energy of 2.51 eV. The cyclovoltamograms of the polymer exhibited the irreversible electrochemical behaviors between the doping and undoping peaks. It was found that the kinetics of the redox process of this conjugated cyclopolymer might be controlled by the diffusion-control process from the experiment of the oxidation current density of polymer versus the scan rate.

  2. Conducting Polymers for Neutron Detection

    International Nuclear Information System (INIS)

    Clare Kimblin; Kirk Miller; Bob Vogel; Bill Quam; Harry McHugh; Glen Anthony; Steve Jones; Mike Grover

    2007-01-01

    Conjugated polymers have emerged as an attractive technology for large-area electronic applications. As organic semiconductors, they can be used to make large-area arrays of diodes or transistors using fabrication techniques developed for polymer coatings, such as spraying and screen-printing. We have demonstrated both neutron and alpha detection using diodes made from conjugated polymers and have done preliminary work to integrate a boron carbide layer into the conventional polymer device structure to capture thermal neutrons. The polymer devices appear to be insensitive to gamma rays, due to their small physical thickness and low atomic number

  3. Synthesis, characterisation and biomedical applications of curcumin conjugated chitosan microspheres.

    Science.gov (United States)

    Saranya, T S; Rajan, V K; Biswas, Raja; Jayakumar, R; Sathianarayanan, S

    2018-04-15

    Curcumin is a diaryl heptanoid of curcuminoids class obtained from Curcuma longa. It possesses various biological activities like anti-inflammatory, hypoglycemic, antioxidant, wound-healing, and antimicrobial activities. Chitosan is a biocompatible, biodegradable and non-toxic natural polymer which enhances the adhesive property of the skin. Chemical conjugation will leads to sustained release action and to enhance the bioavailability. This study aims to synthesis and characterize biocompatible curcumin conjugated chitosan microspheres for bio-medical applications. The Schiff base reaction was carried out for the preparation of curcumin conjugated chitosan by microwave method and it was characterised using FTIR and NMR. Curcumin conjugated chitosan microspheres (CCCMs) were prepared by wet milling solvent evaporation method. SEM analysis showed these CCCMs were 2-5μm spherical particles. The antibacterial activities of the prepared CCCMs were studied against Staphylococcus aureus and Escherichia coli, the zone of inhibition was 28mm and 23mm respectively. Antioxidant activity of the prepared CCCMs was also studied by DPPH and H 2 O 2 method it showed IC 50 esteem value of 216μg/ml and 228μg/ml, and anti-inflammatory activity results showed that CCCMs having IC 50 value of 45μg/ml. The results conclude that the CCCMs having a good antibacterial, antioxidant and anti-inflammatory activities. This, the prepared CCCMs have potential application in preventing skin infections. Copyright © 2017. Published by Elsevier B.V.

  4. Naphtho[1,2-b:5,6-b']dithiophene-Based Conjugated Polymers for Fullerene-Free Inverted Polymer Solar Cells.

    Science.gov (United States)

    Jiang, Zhaoyan; Li, Huan; Wang, Zhen; Zhang, Jianqi; Zhang, Yajie; Lu, Kun; Wei, Zhixiang

    2018-03-23

    Three novel copolymers based on zigzag naphthodithiophene (zNDT) with different aromatic rings as π bridges and different core side substitutions are designed and synthesized (PzNDT-T-1,3-bis(4-(2-ethylhexyl)-thiophen-2-yl)-5,7-bis(2-ethylhexyl)benzo[1,2-c:4,5-c']-dithiophene-4,8-dione (BDD), PzNDT-TT-BDD, and PzNDTP-T-BDD, respectively). The 2D conjugation structure and molecular planarity of the polymers can be effectively altered through the modification of conjugated side chains and π-bridges. These alterations contribute to the variation in energy levels, light absorption capacity, and morphology compatibility of the polymers. When blended with the nonfullerene acceptor (2,2'-[(4,4,9,9-tetrahexyl-4,9-dihydro-sindaceno[1,2-b:5,6-b']dithiophene-2,7-diyl)bis[methylidyne(3-oxo-1H-indene-2,1(3H)-diylidene)

  5. Conjugated Polymers Containing BODIPY and Fluorene Units for Sensitive Detection of CN− Ions: Site-Selective Synthesis, Photo-Physical and Electrochemical Properties

    Directory of Open Access Journals (Sweden)

    Tian He

    2017-10-01

    Full Text Available Conjugated polymers containing distinct molecular units are expected to be very interesting because of their unique properties endowed by these units and the formed conjugated polymers. Herein, four new conjugated copolymers based on fluorene and 4,4’-difluoro-4-bora-3a,4a-diaza-s-indacene (BODIPY have been designed and synthesized via Sonogashira polymerization. The fluorene unit was attached to the 3,5- or 2,6-positions of BODIPY by ethynylenes or p-diacetylenebenzene. The obtained polymers show good thermal stability and broad absorption in the wavelength range from 300 to 750 nm. The effects of site-selective copolymerization and conjugation length along the polymer backbone on the optoelectronic and electrochemical properties of these copolymers were systematically studied by UV-Vis spectroscopy, photoluminescence (PL and cyclic voltammetry. Besides, it is found that the BODIPY-based copolymers exhibit selectively sensitive responses to cyanide anions, resulting in obvious change of UV-Vis absorption spectra and significant fluorescence quenching of the polymers among various common anions.

  6. Semi-metallic, strong and stretchable wet-spun conjugated polymer microfibers

    KAUST Repository

    Zhou, Jian

    2015-01-21

    A dramatic improvement in electrical conductivity is necessary to make conductive polymer fibers viable candidates in applications such as flexible electrodes, conductive textiles, and fast-response sensors and actuators. In this study, high-performance poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS) conjugated polymer microfibers were fabricated via wet-spinning followed by hot-drawing. Due to the combined effects of the vertical hot-drawing process and doping/de-doping the microfibers with ethylene glycol (EG), we achieved a record electrical conductivity of 2804 S cm−1. This is, to the best of our knowledge, a six-fold improvement over the best previously reported value for PEDOT/PSS fibers (467 S cm−1) and a two-fold improvement over the best values for conductive polymer films treated by EG de-doping (1418 S cm−1). Moreover, we found that these highly conductive fibers experience a semiconductor–metal transition at 313 K. They also have superior mechanical properties with a Young\\'s modulus up to 8.3 GPa, a tensile strength reaching 409.8 MPa and a large elongation before failure (21%). The most conductive fiber also demonstrates an extraordinary electrical performance during stretching/unstretching: the conductivity increased by 25% before the fiber rupture point with a maximum strain up to 21%. Simple fabrication of the semi-metallic, strong and stretchable wet-spun PEDOT/PSS microfibers described here could make them available for conductive smart electronics.

  7. Acyclic Diene Metathesis (ADMET Polymerization for Precise Synthesis of Defect-Free Conjugated Polymers with Well-Defined Chain Ends

    Directory of Open Access Journals (Sweden)

    Tahmina Haque

    2015-03-01

    Full Text Available This accounts introduces unique characteristics by adopting the acyclic diene metathesis (ADMET polymerization for synthesis of conjugated polymers, poly(arylene vinylenes, known as promising molecular electronics. The method is more suitable than the other methods in terms of atom efficiency affording defect-free, stereo-regular (exclusive trans polymers with well-defined chain ends; the resultant polymers possess better property than those prepared by the conventional methods. The chain ends (vinyl group in the resultant polymer prepared by ruthenium-carbene catalyst(s can be modified by treating with molybdenum-alkylidene complex (olefin metathesis followed by addition of various aldehyde (Wittig type cleavage, affording the end-functionalized polymers exclusively. An introduction of initiating fragment, the other conjugated segment, and one-pot synthesis of end-functionalized block copolymers, star shape polymers can be achieved by adopting this methodology.

  8. Real-time detection of metal ions using conjugated polymer composite papers.

    Science.gov (United States)

    Lee, Ji Eun; Shim, Hyeon Woo; Kwon, Oh Seok; Huh, Yang-Il; Yoon, Hyeonseok

    2014-09-21

    Cellulose, a natural polymeric material, has widespread technical applications because of its inherent structural rigidity and high surface area. As a conjugated polymer, polypyrrole shows practical potential for a diverse and promising range of future technologies. Here, we demonstrate a strategy for the real-time detection and removal of metal ions with polypyrrole/cellulose (PPCL) composite papers in solution. Simply, the conjugated polymer papers had different chemical/physical properties by applying different potentials to them, which resulted in differentiable response patterns and adsorption efficiencies for individual metal ions. First, large-area PPCL papers with a diameter of 5 cm were readily obtained via vapor deposition polymerization. The papers exhibited both mechanical flexibility and robustness, in which polypyrrole retained its redox property perfectly. The ability of the PPCL papers to recognize metal ions was examined in static and flow cells, in which real-time current change was monitored at five different applied potentials (+1, +0.5, 0, -0.5, and -1 V vs. Ag/AgCl). Distinguishable signals in the PPCL paper responses were observed for individual metal ions through principal component analysis. Particularly, the PPCL papers yielded unique signatures for three metal ions, Hg(ii), Ag(i), and Cr(iii), even in a real sample, groundwater. The sorption of metal ions by PPCL papers was examined in the flow system. The PPCL papers had a greatly superior adsorption efficiency for Hg(ii) compared to that of the other metal ions. With the strong demand for the development of inexpensive, flexible, light-weight, and environmentally friendly devices, the fascinating characteristics of these PPCL papers are likely to provide good opportunities for low-cost paper-based flexible or wearable devices.

  9. Fine-tuning of electronic properties in donor-acceptor conjugated polymers based on oligothiophenes

    Science.gov (United States)

    Imae, Ichiro; Sagawa, Hitoshi; Harima, Yutaka

    2018-03-01

    A novel series of donor-acceptor conjugated polymers having oligothiophenes with well-defined structures were synthesized and their optical, electrochemical, and photovoltaic properties were investigated. It was found that the absorption bands of polymers were red-shifted with increasing number of ethylenedioxy groups added to each oligothiophene unit and that their band edges reached over 1000 nm. The systematical fine-tuning of the electronic properties was achieved using the chemical structures of oligothiophene units. Photovoltaic cells based on polymer/(6,6)-phenyl C61 butyric acid methyl ester (PC61BM) exhibited power conversion efficiencies in the range from 0.004 to 1.10%, reflecting the electronic properties of the polymers.

  10. Nature of the Binding Interactions between Conjugated Polymer Chains and Fullerenes in Bulk Heterojunction Organic Solar Cells

    KAUST Repository

    Ravva, Mahesh Kumar; Wang, Tonghui; Bredas, Jean-Luc

    2016-01-01

    Blends of π-conjugated polymers and fullerene derivatives are ubiquitous as the active layers of organic solar cells. However, a detailed understanding of the weak noncovalent interactions at the molecular level between the polymer chains

  11. Bipolar and Unipolar Silylene-Diphenylene σ-π Conjugated Polymer Route for Highly Efficient Electrophosphorescence

    Science.gov (United States)

    Chang, Yao-Tang; Sharma, Sunil; Hung, Miao-Ken; Lee, Yu-Hsuan; Chen, Show-An

    2016-12-01

    σ-π conjugated polymer strategy is proposed for designing electroluminescent host polymers with silylene-diphenylene as the backbone repeat unit giving a high triplet energy (ET = 2.67 eV). By incorporation of high ET (3.0 eV) electron (oxadiazole, OXD) and hole (triphenyl amine, TPA) transport moieties, or TPA alone (in this case, the main chain acts as electron transport channel) as side arms on the silylene, the high ET bipolar and unipolar polymers are formed, allowing a use of iridium green phosphor (Ir(ppy)2(acac), Ir-G) (ET = 2.40 eV) as the dopant. The matching of energy levels of the dopant with the hosts, leading to charge trapping into it; and singlets and triplets of the exciplex and excimer can be harvested via energy transfer to the dopant. Using these host-guest systems as the emitting layer, chlorinated indium-tin-oxide (Cl-ITO) as the anode, and benzimidazole derivative (TPBI) as the electron transport layer, this two-layer device gives the high luminance efficiency 80.1 cd/A and external quantum efficiency 21.2%, which is the best among the report values for polymer light emitting diode (PLED) in the literatures. This example manifests that σ-π conjugated polymer strategy is a promising route for designing polymer host for efficient electrophosphorescence.

  12. Design, synthesis and photovoltaic properties of a series of new acceptor-pended conjugated polymers

    Institute of Scientific and Technical Information of China (English)

    Zhihong; Wu; Yongxiang; Zhu; Wei; Li; Yunping; Huang; Junwu; Chen; Chunhui; Duan; Fei; Huang; Yong; Cao

    2016-01-01

    A series of novel acceptor-pended conjugated polymers featuring a newly developed carbazole-derived unit are designed and synthesized. The relationships between chemical structure and optoelectronic properties of the polymers are systematically investigated.The control of UV-Vis absorption spectra and energy levels in resulting polymers are achieved by introducing suitable pended acceptor units. The photovoltaic properties of the resulting polymers are evaluated by blending the polymers with(6,6)-phenyl-C71-butyric acid methyl ester. The resulting solar cells exhibit moderate performances with high open-circuit voltage. Charge transport properties and morphology were investigated to understand the performance of corresponding solar cells.

  13. Carrier heating in disordered conjugated polymers in electric field

    Energy Technology Data Exchange (ETDEWEB)

    Vukmirovic, Nenad; Wang, Lin-Wang

    2010-01-26

    The electric field dependence of charge carrier transport and the effect of carrier heating in disordered conjugated polymers were investigated. A parameter-free multiscale methodology consisting of classical molecular dynamics simulation for the generation of the atomic structure, large system electronic structure and electron-phonon coupling constants calculations and the procedure for extracting the bulk polymer mobility, was used. The results suggested that the mobility of a fully disordered poly(3-hexylthiophene) (P3HT) polymer increases with electric field which is consistent with the experimental results on samples of regiorandom P3HT and different from the results on more ordered regioregular P3HT polymers, where the opposite trend is often observed at low electric fields. We calculated the electric field dependence of the effective carrier temperature and showed however that the effective temperature cannot be used to replace the joint effect of temperature and electric field, in contrast to previous theoretical results from phenomenological models. Such a difference was traced to originate from the use of simplified Miller-Abrahams hopping rates in phenomenological models in contrast to our considerations that explicitly take into account the electronic state wave functions and the interaction with all phonon modes.

  14. Control of gain in conjugated polymers and perylene dyes

    International Nuclear Information System (INIS)

    Sheridan, A.

    2001-03-01

    This thesis presents an investigation into the factors which control the gain and amplification properties in conjugated materials. Conjugated polymers and perylene dyes are highly fluorescent, are easy to process into thin films, and exhibit strong amplification over a broad gain bandwidth making them ideal for use in lasers and amplifiers. The stimulated emission created when thin films of the red emitting polymer poly(2-methoxy-5-(2'-ethylhexyloxy)-p-phenylenvinylene) (MEH-PPV) were photoexcited with high energy laser pulses was investigated. This was characterised by a dramatic narrowing of the emission spectrum which has been assigned to amplified spontaneous emission (ASE). The emission was found to have a gaussian profile and the gain coefficient was found to be 4 cm -1 . The temperature dependence of the absorption, photoluminescence and ASE of films of MEH-PPV was measured. The effect of film morphology on the photophysical properties was investigated by using films cast from two spinning solvents, chlorobenzene (CB) and tetrahydrofuran (THF). Film morphology was found to greatly affect the temperature dependence. A particularly important property is the spectral position of the ASE and the factors which affect it. By controlling the film thickness close to the cut-off thickness for waveguiding in the polymer film it was shown that the peak position of the ASE could be tuned by 31 nm. Modelling of the waveguide modes in the polymer films was used to explain this effect. The cut-off wavelength for each film was measured and good agreement with the theory was found. In order to investigate ways in which energy transfer could be used to control the emission, two perylene dyes were used as a donor-acceptor pair in a host matrix of poly methymethacralate (PMMA). The position of the ASE was found to depend on the acceptor concentration. Measurements of the photoluminescence quantum yield and time-resolved luminescence measurements showed that the energy transfer

  15. Influence of Molecular Conformations and Microstructure on the Optoelectronic Properties of Conjugated Polymers

    KAUST Repository

    Botiz, Ioan; Stingelin, Natalie

    2014-01-01

    It is increasingly obvious that the molecular conformations and the long-range arrangement that conjugated polymers can adopt under various experimental conditions in bulk, solutions or thin films, significantly impact their resulting optoelectronic properties. As a consequence, the functionalities and efficiencies of resulting organic devices, such as field-effect transistors, light-emitting diodes, or photovoltaic cells, also dramatically change due to the close structure/property relationship. A range of structure/optoelectronic properties relationships have been investigated over the last few years using various experimental and theoretical methods, and, further, interesting correlations are continuously revealed by the scientific community. In this review, we discuss the latest findings related to the structure/optoelectronic properties interrelationships that exist in organic devices fabricated with conjugated polymers in terms of charge mobility, absorption, photoluminescence, as well as photovoltaic properties. © 2014 by the authors.

  16. Influence of Molecular Conformations and Microstructure on the Optoelectronic Properties of Conjugated Polymers

    Directory of Open Access Journals (Sweden)

    Ioan Botiz

    2014-03-01

    Full Text Available It is increasingly obvious that the molecular conformations and the long-range arrangement that conjugated polymers can adopt under various experimental conditions in bulk, solutions or thin films, significantly impact their resulting optoelectronic properties. As a consequence, the functionalities and efficiencies of resulting organic devices, such as field-effect transistors, light-emitting diodes, or photovoltaic cells, also dramatically change due to the close structure/property relationship. A range of structure/optoelectronic properties relationships have been investigated over the last few years using various experimental and theoretical methods, and, further, interesting correlations are continuously revealed by the scientific community. In this review, we discuss the latest findings related to the structure/optoelectronic properties interrelationships that exist in organic devices fabricated with conjugated polymers in terms of charge mobility, absorption, photoluminescence, as well as photovoltaic properties.

  17. Influence of Molecular Conformations and Microstructure on the Optoelectronic Properties of Conjugated Polymers

    KAUST Repository

    Botiz, Ioan

    2014-03-19

    It is increasingly obvious that the molecular conformations and the long-range arrangement that conjugated polymers can adopt under various experimental conditions in bulk, solutions or thin films, significantly impact their resulting optoelectronic properties. As a consequence, the functionalities and efficiencies of resulting organic devices, such as field-effect transistors, light-emitting diodes, or photovoltaic cells, also dramatically change due to the close structure/property relationship. A range of structure/optoelectronic properties relationships have been investigated over the last few years using various experimental and theoretical methods, and, further, interesting correlations are continuously revealed by the scientific community. In this review, we discuss the latest findings related to the structure/optoelectronic properties interrelationships that exist in organic devices fabricated with conjugated polymers in terms of charge mobility, absorption, photoluminescence, as well as photovoltaic properties. © 2014 by the authors.

  18. Charge carrier motion in disordered conjugated polymers: a multiscale ab-initio study

    Energy Technology Data Exchange (ETDEWEB)

    Vukmirovic, Nenad; Wang, Lin-Wang

    2009-11-10

    We developed an ab-initio multiscale method for simulation of carrier transport in large disordered systems, based on direct calculation of electronic states and electron-phonon coupling constants. It enabled us to obtain the never seen before rich microscopic details of carrier motion in conjugated polymers, which led us to question several assumptions of phenomenological models, widely used in such systems. The macroscopic mobility of disordered poly(3- hexylthiophene) (P3HT) polymer, extracted from our simulation, is in agreement with experimental results from the literature.

  19. Solvent-dependent self-assembly and ordering in slow-drying semi-crystalline conjugated polymer solutions

    KAUST Repository

    Zhao, Kui; Yu, Xinhong; Li, Ruipeng; Amassian, Aram; Han, Yanchun

    2015-01-01

    The mechanistic understanding of the intrinsic molecular self-assembly of conjugated polymers is of immense importance to controlling the microstructure development in organic semiconducting thin films, with meaningful impact on charge transport

  20. Bactericidal Specificity and Resistance Profile of Poly(Quaternary Ammonium) Polymers and Protein-Poly(Quaternary Ammonium) Conjugates.

    Science.gov (United States)

    Ji, Weihang; Koepsel, Richard R; Murata, Hironobu; Zadan, Sawyer; Campbell, Alan S; Russell, Alan J

    2017-08-14

    Antibacterial polymers are potentially powerful biocides that can destroy bacteria on contact. Debate in the literature has surrounded the mechanism of action of polymeric biocides and the propensity for bacteria to develop resistance to them. There has been particular interest in whether surfaces with covalently coupled polymeric biocides have the same mechanism of action and resistance profile as similar soluble polymeric biocides. We designed and synthesized a series of poly(quaternary ammonium) polymers, with tailorable molecular structures and architectures, to engineer their antibacterial specificity and their ability to delay the development of bacterial resistance. These linear poly(quaternary ammonium) homopolymers and block copolymers, generated using atom transfer radical polymerization, had structure-dependent antibacterial specificity toward Gram positive and negative bacterial species. When single block copolymers contained two polymer segments of differing antibacterial specificity, the polymer combined the specificities of its two components. Nanoparticulate human serum albumin-poly(quaternary ammonium) conjugates of these same polymers, synthesized via "grafting from" atom transfer radical polymerization, were strongly biocidal and also exhibited a marked decrease in the rate of bacterial resistance development relative to linear polymers. These protein-biocide conjugates mimicked the behavior of surface-presented polycationic biocides rather than their nonproteinaceous counterparts.

  1. High operational and environmental stability of high-mobility conjugated polymer field-effect transistors through the use of molecular additives

    KAUST Repository

    Nikolka, Mark; Nasrallah, Iyad; Rose, Bradley Daniel; Ravva, Mahesh Kumar; Broch, Katharina; Sadhanala, Aditya; Harkin, David; Charmet, Jerome; Hurhangee, Michael; Brown, Adam; Illig, Steffen; Too, Patrick; Jongman, Jan; McCulloch, Iain; Bredas, Jean-Luc; Sirringhaus, Henning

    2016-01-01

    Due to their low-temperature processing properties and inherent mechanical flexibility, conjugated polymer field-effect transistors (FETs) are promising candidates for enabling flexible electronic circuits and displays. Much progress has been made on materials performance; however, there remain significant concerns about operational and environmental stability, particularly in the context of applications that require a very high level of threshold voltage stability, such as active-matrix addressing of organic light-emitting diode displays. Here, we investigate the physical mechanisms behind operational and environmental degradation of high-mobility, p-type polymer FETs and demonstrate an effective route to improve device stability. We show that water incorporated in nanometre-sized voids within the polymer microstructure is the key factor in charge trapping and device degradation. By inserting molecular additives that displace water from these voids, it is possible to increase the stability as well as uniformity to a high level sufficient for demanding industrial applications.

  2. High operational and environmental stability of high-mobility conjugated polymer field-effect transistors through the use of molecular additives

    KAUST Repository

    Nikolka, Mark

    2016-12-12

    Due to their low-temperature processing properties and inherent mechanical flexibility, conjugated polymer field-effect transistors (FETs) are promising candidates for enabling flexible electronic circuits and displays. Much progress has been made on materials performance; however, there remain significant concerns about operational and environmental stability, particularly in the context of applications that require a very high level of threshold voltage stability, such as active-matrix addressing of organic light-emitting diode displays. Here, we investigate the physical mechanisms behind operational and environmental degradation of high-mobility, p-type polymer FETs and demonstrate an effective route to improve device stability. We show that water incorporated in nanometre-sized voids within the polymer microstructure is the key factor in charge trapping and device degradation. By inserting molecular additives that displace water from these voids, it is possible to increase the stability as well as uniformity to a high level sufficient for demanding industrial applications.

  3. Alcohol vapor sensory properties of nanostructured conjugated polymers

    International Nuclear Information System (INIS)

    Bearzotti, Andrea; Macagnano, Antonella; Pantalei, Simone; Zampetti, Emiliano; Venditti, Iole; Fratoddi, Ilaria; Vittoria Russo, Maria

    2008-01-01

    The response to relative humidity (RH) and alcohol vapors of resistive-type sensors based on nanobeads of conjugated polymers, namely polyphenylacetylene (PPA) and copolymer poly[phenylacetylene-(co-2-hydroxyethyl methacrylate)] (P(PA/HEMA)), were investigated. Sensors based on ordered arrays of these nanostructured polymeric materials showed stable and reproducible current intensity variations in the range 10-90% of relative humidity at room temperature. Both polymers also showed sensitivity to aliphatic chain primary alcohols, and a fine tuning of the sensor response was obtained by varying the chain length of the alcohol in relation to the polarity. The nanostructured feature of polymeric-based membranes seems to have an effect on the sensing response and an enhancement of the sensitivity was observed for the response to water and alcohol vapor variations with respect to previous studies based on amorphous polyphenylacetylene. High stability of the polymeric nanostructured membranes was detected with no aging after two weeks in continuum stressing measurement conditions.

  4. Anthracene-containing wide-band-gap conjugated polymers for high-open-circuit-voltage polymer solar cells.

    Science.gov (United States)

    Gong, Xue; Li, Cuihong; Lu, Zhen; Li, Guangwu; Mei, Qiang; Fang, Tao; Bo, Zhishan

    2013-07-25

    The synthesis, characterization, and photophysical and photovoltaic properties of two anthracene-containing wide-band-gap donor and acceptor (D-A) alternating conjugated polymers (P1 and P2) are described. These two polymers absorb in the range of 300-600 nm with a band gap of about 2.12 eV. Polymer solar cells with P1:PC71 BM as the active layer demonstrate a power conversion efficiency (PCE) of 2.23% with a high Voc of 0.96 V, a Jsc of 4.4 mA cm(-2) , and a comparable fill factor (FF) of 0.53 under simulated solar illumination of AM 1.5 G (100 mW cm(-2) ). In addition, P2:PC71 BM blend-based solar cells exhibit a PCE of 1.42% with a comparable Voc of 0.89 V, a Jsc of 3.0 mA cm(-2) , and an FF of 0.53. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. Stability issues of conjugated polymer / fullerene solar cells from a chemical viewpoint

    NARCIS (Netherlands)

    Hummelen, J.C.; Knol, J.; Sánchez, L.

    2001-01-01

    The efficiency of energy conversion and the stability or lifetime of ‘plastic’ photovoltaic cells, based on conjugated polymer/ fullerene blends, are the two main issues to be improved for this type of devices. The stability of these PV cells depends potentially on a large number of factors. A brief

  6. Effects of chemical modifications on photophysics and exciton dynamics on {pi}-conjugation attenuated and metal-chelated photoconducting polymers

    Energy Technology Data Exchange (ETDEWEB)

    Chen, L. X.; Jager, W. J. H.; Gosztola, D. J.; Niemczyk, M. P.; Wasielewski, M. R.

    2000-03-11

    Effects of two types of chemical modifications on photoconducting polymers consisting of polyphenylenevinylene (PPV) derivatives are studied by static and ultrafast transient optical spectroscopy as well as semi-empirical ZINDO calculations. The first type of modification inserts 2,2{prime}-bipyridyl-5-vinylene units (bpy V) in the PPV backbone, and the second type involves metal-chelation with the bpy sites. Photoluminescence and exciton dynamics of polymers 1 and 2 with PV:bpyV ratios of 1 and 3 were examined in solution, and compared to those of the homopolymer, poly(2,5-bis(2{prime}-ethylhexyloxy)-1,4-phenylenevinylene) (BEH-PPV). Similar studies were carried out for several metal-chelated polymers. These results can be explained by changes in {pi}-conjugation throughout the polymer backbone. The attenuation in {pi}-conjugation by the chemical modifications transforms a conducting polymer from one-dimensional semiconductor to molecular aggregates.

  7. Pluronic-lysozyme conjugates as anti-adhesive and antibacterial bifunctional polymers for surface coating

    NARCIS (Netherlands)

    Muszanska, A.K.; Busscher, H.J.; Herrmann, A.; Mei, van der H.C.; Norde, W.

    2011-01-01

    This paper describes the preparation and characterization of polymer protein conjugates composed of a synthetic triblock copolymer with a central polypropylene oxide (PPO) block and two terminal polyethylene oxide (PEO) segments, Pluronic F-127, and the antibacterial enzyme lysozyme attached to the

  8. Carrier Transport Enhancement in Conjugated Polymers through Interfacial Self-Assembly of Solution-State Aggregates

    KAUST Repository

    Zhao, Kui; Khan, Hadayat Ullah; Li, Ruipeng; Hu, Hanlin; Amassian, Aram

    2016-01-01

    and extension of the conjugated backbone of the polymer which clearly translate to significant improvements of carrier transport at the semiconductor-dielectric interface in organic thin film transistors. This study points to opportunities in combining

  9. Synthesis and characterization of a low bandgap conjugated polymer for bulk heterojunction photovoltaic cells

    NARCIS (Netherlands)

    Dhanabalan, A.; Duren, van J.K.J.; Hal, van P.A.; Dongen, van J.L.J.; Janssen, R.A.J.

    2001-01-01

    Low optical bandgap conjugated polymers may improve the efficiency of organic photovoltaic devices by increasing the absorption in the visible and near infrared region of the solar spectrum. Here we demonstrate that condensation polymerization of

  10. Theory of interfacial charge-transfer complex photophysics in π-conjugated polymer-fullerene blends

    Science.gov (United States)

    Aryanpour, K.; Psiachos, D.; Mazumdar, S.

    2010-03-01

    We present a theory of the electronic structure and photophysics of 1:1 blends of derivatives of polyparaphenylenevinylene and fullerenes [1]. Within the same Coulomb-correlated Hamiltonian applied previously to interacting chains of single-component π-conjugated polymers [2], we find an exciplex state that occurs below the polymer's optical exciton. Weak absorption from the ground state occurs to the exciplex. We explain transient photoinduced absorptions in the blend [3], observed for both above-gap and below-gap photoexcitations, within our theory. Photoinduced absorptions for above-gap photoexcitation are from the optical exciton as well as the exciplex, while for below-gap photoexcitation induced absorptions are from the exciplex alone. In neither case are free polarons generated in the time scale of the experiment. Importantly, the photophysics of films of single-component π-conjugated polymers and blends can both be understood by extending Mulliken's theory of ground state charge-transfer to the case of excited state charge-transfer. [1] K. Aryanpour, D. Psiachos, and S. Mazumdar, arXiv:0908.0366 [2] D. Psiachos and S. Mazumdar, Phys. Rev. B. 79 155106 (2009) [3] T. Drori et al., Phys. Rev. Lett. 101, 037402 (2008)

  11. Impact of the Enhanced Permeability and Retention (EPR Effect and Cathepsins Levels on the Activity of Polymer-Drug Conjugates

    Directory of Open Access Journals (Sweden)

    Amit K. Rajora

    2014-08-01

    Full Text Available Polymer-drug conjugates have demonstrated clinical potential in the context of anticancer therapy. However, such promising results have, to date, failed to translate into a marketed product. Polymer-drug conjugates rely on two factors for activity: (i the presence of a defective vasculature, for passive accumulation of this technology into the tumour tissue (enhanced permeability and retention (EPR effect and (ii the presence of a specific trigger at the tumour site, for selective drug release (e.g., the enzyme cathepsin B. Here, we retrospectively analyse literature data to investigate which tumour types have proved more responsive to polymer-drug conjugates and to determine correlations between the magnitude of the EPR effect and/or expression of cathepsin B. Lung, breast and ovarian cancers showed the highest response rate (30%, 47% and 41%, respectively for cathepsin-activated conjugates and 31%, 43%, 40%, across all conjugates. An analysis of literature data on cathepsin content in various tumour types showed that these tumour types had high cathepsin content (up to 3835 ng/mg for lung cancer, although marked heterogeneity was observed across different studies. In addition, these tumour types were also reported as having a high EPR effect. Our results suggest that a pre-screening of patient population could bring a more marked clinical benefit.

  12. Solvent-resistant organic transistors and thermally stable organic photovoltaics based on cross-linkable conjugated polymers

    KAUST Repository

    Kim, Hyeongjun

    2012-01-10

    Conjugated polymers, in general, are unstable when exposed to air, solvent, or thermal treatment, and these challenges limit their practical applications. Therefore, it is of great importance to develop new materials or methodologies that can enable organic electronics with air stability, solvent resistance, and thermal stability. Herein, we have developed a simple but powerful approach to achieve solvent-resistant and thermally stable organic electronic devices with a remarkably improved air stability, by introducing an azide cross-linkable group into a conjugated polymer. To demonstrate this concept, we have synthesized polythiophene with azide groups attached to end of the alkyl chain (P3HT-azide). Photo-cross-linking of P3HT-azide copolymers dramatically improves the solvent resistance of the active layer without disrupting the molecular ordering and charge transport. This is the first demonstration of solvent-resistant organic transistors. Furthermore, the bulk-heterojunction organic photovoltaics (BHJ OPVs) containing P3HT-azide copolymers show an average efficiency higher than 3.3% after 40 h annealing at an elevated temperature of 150 °C, which represents one of the most thermally stable OPV devices reported to date. This enhanced stability is due to an in situ compatibilizer that forms at the P3HT/PCBM interface and suppresses macrophase separation. Our approach paves a way toward organic electronics with robust and stable operations. © 2011 American Chemical Society.

  13. Sensitization of nano-porous ZnO photo-anode by a conjugated conducting polymer

    Energy Technology Data Exchange (ETDEWEB)

    Sirimanne, P.M. [Nano-Science Laboratory, Institute of Fundamental Studies, Hantana Road, Kandy (Sri Lanka); Environmental and Renewable Energy Systems Division, Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193 (Japan); Premalal, E.V.A. [Nano-Science Laboratory, Institute of Fundamental Studies, Hantana Road, Kandy (Sri Lanka); Minoura, H. [Environmental and Renewable Energy Systems Division, Graduate School of Engineering, Gifu University, 1-1 Yanagido, Gifu 501-1193 (Japan)

    2011-01-15

    Hybrid ZnO films are prepared via one-step electrochemical process. Extraction of organic component from hybrid films results tiny wires like ZnO columns perpendicular to the substrate. Visible light sensitive-conjugated polymer poly(2-methoxy-5-[2 ethylhexyloxy]-1-4-phenylenevinylene, MEH-PPV) was embedded in highly porous ZnO ceramic by a solvent vaporization technique. An attempt was made to fabricate polymer sensitized photovoltaic cell by coupling polymer embedded ZnO electrodes with an electrolyte. Maximum photovoltage of 490 mV is observed for the cell with the configuration of ZnO vertical stroke MEH-PPV vertical stroke I{sup -}/I{sub 3}{sup -} cell. (author)

  14. Carrier Transport Enhancement in Conjugated Polymers through Interfacial Self-Assembly of Solution-State Aggregates

    KAUST Repository

    Zhao, Kui

    2016-07-13

    We demonstrate that local and long range orders of poly(3-hexylthiophene) (P3HT) semicrystalline films can be synergistically improved by combining chemical functionalization of the dielectric surface with solution-state disentanglement and pre-aggregation of P3HT in a theta solvent, leading to a very significant enhancement of the field effect carrier mobility. The pre-aggregation and surface functionalization effects combine to enhance the carrier mobility nearly 100-fold as compared with standard film preparation by spin-coating, and nearly 10-fold increase over the benefits of pre-aggregation alone. In situ quartz crystal microbalance with dissipation (QCM-D) experiments reveal enhanced deposition of pre-aggregates on surfaces modified with an alkyl-terminated self-assembled monolayer (SAM) in comparison to un-aggregated polymer chains. Additional investigations reveal the combined pre-aggregation and surface functionalization significantly enhances local order of the conjugated polymer through planarization and extension of the conjugated backbone of the polymer which clearly translate to significant improvements of carrier transport at the semiconductor-dielectric interface in organic thin film transistors. This study points to opportunities in combining complementary routes, such as well-known pre-aggregation with substrate chemical functionalization, to enhance the polymer self-assembly and improve its interfacial order with benefits for transport properties.

  15. Understanding Interfacial Alignment in Solution Coated Conjugated Polymer Thin Films

    International Nuclear Information System (INIS)

    Qu, Ge; Zhao, Xikang; Newbloom, Gregory M.; Zhang, Fengjiao; Mohammadi, Erfan

    2017-01-01

    Domain alignment in conjugated polymer thin films can significantly enhance charge carrier mobility. However, the alignment mechanism during meniscus-guided solution coating remains unclear. Furthermore, interfacial alignment has been rarely studied despite its direct relevance and critical importance to charge transport. In this study, we uncover a significantly higher degree of alignment at the top interface of solution coated thin films, using a donor–acceptor conjugated polymer, poly(diketopyrrolopyrrole-co-thiopheneco- thieno[3,2-b]thiophene-co-thiophene) (DPP2T-TT), as the model system. At the molecular level, we observe in-plane π–π stacking anisotropy of up to 4.8 near the top interface with the polymer backbone aligned parallel to the coating direction. The bulk of the film is only weakly aligned with the backbone oriented transverse to coating. At the mesoscale, we observe a well-defined fibril-like morphology at the top interface with the fibril long axis pointing toward the coating direction. Significantly smaller fibrils with poor orientational order are found on the bottom interface, weakly aligned orthogonal to the fibrils on the top interface. The high degree of alignment at the top interface leads to a charge transport anisotropy of up to 5.4 compared to an anisotropy close to 1 on the bottom interface. We attribute the formation of distinct interfacial morphology to the skin-layer formation associated with high Peclet number, which promotes crystallization on the top interface while suppressing it in the bulk. As a result, we further infer that the interfacial fibril alignment is driven by the extensional flow on the top interface arisen from increasing solvent evaporation rate closer to the meniscus front.

  16. Hybrid polymer-inorganic photovoltaic cells

    NARCIS (Netherlands)

    Beek, W.J.E.; Janssen, R.A.J.; Merhari, L.

    2009-01-01

    Composite materials made from organic conjugated polymers and inorganic semiconductors such as metal oxides attract considerable interest for photovoltaic applications. Hybrid polymer-inorganic solar cells offer the opportunity to combine the beneficial properties of the two materials in charge

  17. Ambipolar Organic Phototransistors with p-Type/n-Type Conjugated Polymer Bulk Heterojunction Light-Sensing Layers

    KAUST Repository

    Nam, Sungho; Han, Hyemi; Seo, Jooyeok; Song, Myeonghun; Kim, Hwajeong; Anthopoulos, Thomas D.; McCulloch, Iain; Bradley, Donal D C; Kim, Youngkyoo

    2016-01-01

    Ambipolar organic phototransistors with sensing channel layers, featuring p-type and n-type conjugated polymer bulk heterojunctions, exhibit outstanding light-sensing characteristics in both p-channel and n-channel sensing operation modes.

  18. Ambipolar Organic Phototransistors with p-Type/n-Type Conjugated Polymer Bulk Heterojunction Light-Sensing Layers

    KAUST Repository

    Nam, Sungho

    2016-11-18

    Ambipolar organic phototransistors with sensing channel layers, featuring p-type and n-type conjugated polymer bulk heterojunctions, exhibit outstanding light-sensing characteristics in both p-channel and n-channel sensing operation modes.

  19. Design of porphyrin-based conjugated microporous polymers with enhanced singlet oxygen productivity

    Czech Academy of Sciences Publication Activity Database

    Hynek, Jan; Rathouský, Jiří; Demel, Jan; Lang, Kamil

    2016-01-01

    Roč. 6, č. 50 (2016), s. 44279-44287 ISSN 2046-2069 R&D Projects: GA ČR(CZ) GA16-15020S Institutional support: RVO:61388980 ; RVO:61388955 Keywords : Conjugated microporous polymers * Crystalline materials * Metal organic framework * biomimetic catalysis Subject RIV: CA - Inorganic Chemistry; CF - Physical ; Theoretical Chemistry (UFCH-W) Impact factor: 3.108, year: 2016

  20. Alkylated indacenodithieno[3,2-b]thiophene-based all donor ladder-type conjugated polymers for organic thin film transistors

    KAUST Repository

    Lu, Rimei

    2018-01-29

    We report the synthesis of a series of indacenodithieno[3,2-b]thiophene (IDTT) based conjugated polymers by copolymerization with three different electron rich co-monomers [thiophene (T), thieno[3,2-b]thiophene (TT) and dithieno[3,2-b:2\\',3\\'-d]thiophene (DTT)] under Stille coupling conditions. The resulting all-donor polymers show very good solubility in common solvents and exhibit similar optical, thermal and electronic properties. However, the performance of these semiconductors in thin film transistor devices varied and was highly dependent on the nature of the co-monomer. All polymers exhibited unipolar p-type charge transport behaviour, with the mobility values following the trend of IDTT-TT>IDTT-DTT>IDTT-T. The peak saturation mobility value of IDTT-TT was extracted to be 1.1 cm2V-1s-1, amongst the highest mobility for all-donor conjugated polymers reported to date.

  1. Indaceno-Based Conjugated Polymers for Polymer Solar Cells.

    Science.gov (United States)

    Yin, Yuli; Zhang, Yong; Zhao, Liancheng

    2018-01-04

    Polymer solar cells have received considerable attention due to the advantages of low material cost, tunable band gaps, ultralight weight, and high flexible properties, and they have been a promising organic photovoltaic technology for alternative non-renewable fossil fuels for the past decade. Inspired by these merits, numerous state-of-the-art organic photovoltaic materials have been constructed. Among them, indaceno-based polymer materials have made an impact in obtaining an impressive power conversion efficiency of more than 11%, which shows the momentous potential of this class of materials for commercial applications. In this review, recent progress of indaceno-based organic polymer solar cells are reviewed, and the structure-property device performance correlations of the reported materials are highlighted. Then, common regularities of these successful cases are collected, and encouraging viewpoints on the further development of more exciting indaceno-based organic photovoltaic materials are provided. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Effects of alkyl chain positioning on conjugated polymer microstructure and field-effect mobilities

    KAUST Repository

    Schroeder, Bob C.; Nielsen, Christian B.; Westacott, Paul; Smith, Jeremy; Rossbauer, Stephan; Anthopoulos, Thomas D.; Stingelin, Natalie; McCulloch, Iain

    2015-01-01

    Solubilizing alkyl chains play a crucial role in the design of semiconducting polymers because they define the materials solubility and processability as well as both the crystallinity and solid-state microstructure. In this paper, we present a scarcely explored design approach by attaching the alkyl side chains on one side (cis-) or on both sides (trans-) of the conjugated backbone. We further investigate the effects of this structural modification on the solid-state properties of the polymers and on the charge-carrier mobilities in organic thin-film transistors. Copyright © Materials Research Society 2015

  3. Effects of alkyl chain positioning on conjugated polymer microstructure and field-effect mobilities

    KAUST Repository

    Schroeder, Bob C.

    2015-07-02

    Solubilizing alkyl chains play a crucial role in the design of semiconducting polymers because they define the materials solubility and processability as well as both the crystallinity and solid-state microstructure. In this paper, we present a scarcely explored design approach by attaching the alkyl side chains on one side (cis-) or on both sides (trans-) of the conjugated backbone. We further investigate the effects of this structural modification on the solid-state properties of the polymers and on the charge-carrier mobilities in organic thin-film transistors. Copyright © Materials Research Society 2015

  4. Comparison of selenophene and thienothiophene incorporation into pentacyclic lactam-based conjugated polymers for organic solar cells

    KAUST Repository

    Kroon, Renee; Melianas, Armantas; Zhuang, Wenliu; Bergqvist, Jonas; Diaz De Zerio Mendaza, Amaia; Steckler, Timothy T.; Yu, Liyang; Bradley, Siobhan J.; Musumeci, Chiara; Gedefaw, Desta; Nann, Thomas; Amassian, Aram; Mü ller, Christian; Inganä s, Olle; Andersson, Mats R.

    2015-01-01

    In this work, we compare the effect of incorporating selenophene versus thienothiophene spacers into pentacyclic lactam-based conjugated polymers for organic solar cells. The two cyclic lactam-based copolymers were obtained via a new synthetic method for the lactam moiety. Selenophene incorporation results in a broader and red-shifted optical absorption while retaining a deep highest occupied molecular orbital level, whereas thienothienophene incorporation results in a blue-shifted optical absorption. Additionally, grazing-incidence wide angle X-ray scattering data indicates edge- and face-on solid state order for the selenophene-based polymer as compared to the thienothiophene-based polymer, which orders predominantly edge-on with respect to the substrate. In polymer:PCBM bulk heterojunction solar cells both materials show a similar open-circuit voltage of ∼0.80-0.84 V, however the selenophene-based polymer displays a higher fill factor of ∼0.70 vs. ∼0.65. This is due to the partial face-on backbone orientation of the selenophene-based polymer, leading to a higher hole mobility, as confirmed by single-carrier diode measurements, and a concomitantly higher fill factor. Combined with improved spectral coverage of the selenophene-based polymer, as confirmed by quantum efficiency experiments, it offers a larger short-circuit current density of ∼12 mA cm. Despite the relatively low molecular weight of both materials, a very robust power conversion efficiency ∼7% is achieved for the selenophene-based polymer, while the thienothiophene-based polymer demonstrates only a moderate maximum PCE of ∼5.5%. Hence, the favorable effects of selenophene incorporation on the photovoltaic performance of pentacyclic lactam-based conjugated polymers are clearly demonstrated.

  5. Comparison of selenophene and thienothiophene incorporation into pentacyclic lactam-based conjugated polymers for organic solar cells

    KAUST Repository

    Kroon, Renee

    2015-09-08

    In this work, we compare the effect of incorporating selenophene versus thienothiophene spacers into pentacyclic lactam-based conjugated polymers for organic solar cells. The two cyclic lactam-based copolymers were obtained via a new synthetic method for the lactam moiety. Selenophene incorporation results in a broader and red-shifted optical absorption while retaining a deep highest occupied molecular orbital level, whereas thienothienophene incorporation results in a blue-shifted optical absorption. Additionally, grazing-incidence wide angle X-ray scattering data indicates edge- and face-on solid state order for the selenophene-based polymer as compared to the thienothiophene-based polymer, which orders predominantly edge-on with respect to the substrate. In polymer:PCBM bulk heterojunction solar cells both materials show a similar open-circuit voltage of ∼0.80-0.84 V, however the selenophene-based polymer displays a higher fill factor of ∼0.70 vs. ∼0.65. This is due to the partial face-on backbone orientation of the selenophene-based polymer, leading to a higher hole mobility, as confirmed by single-carrier diode measurements, and a concomitantly higher fill factor. Combined with improved spectral coverage of the selenophene-based polymer, as confirmed by quantum efficiency experiments, it offers a larger short-circuit current density of ∼12 mA cm. Despite the relatively low molecular weight of both materials, a very robust power conversion efficiency ∼7% is achieved for the selenophene-based polymer, while the thienothiophene-based polymer demonstrates only a moderate maximum PCE of ∼5.5%. Hence, the favorable effects of selenophene incorporation on the photovoltaic performance of pentacyclic lactam-based conjugated polymers are clearly demonstrated.

  6. Multifunctional adhesive polymers: Preactivated thiolated chitosan-EDTA conjugates.

    Science.gov (United States)

    Netsomboon, Kesinee; Suchaoin, Wongsakorn; Laffleur, Flavia; Prüfert, Felix; Bernkop-Schnürch, Andreas

    2017-02-01

    The aim of this study was to synthesis preactivated thiolated chitosan-EDTA (Ch-EDTA-cys-2MNA) conjugates exhibiting in particular high mucoadhesive, cohesive and chelating properties. Thiol groups were coupled with chitosan by carbodiimide reaction and further preactivated by attachment with 2-mercaptonicotinic acid (2MNA) via disulfide bond formation. Determinations of primary amino and sulfhydryl groups were performed by TNBS and Ellman's tests, respectively. Cytotoxicity was screened by resazurin assay in Caco-2 cells. Mucoadhesive properties and bivalent cation binding capacity with Mg 2+ and Ca 2+ in comparison to chitosan-EDTA (Ch-EDTA) and thiolated Ch-EDTA (Ch-EDTA-cys) were evaluated. Determination of 2MNA and total sulfhydryl groups indicated that 80% of thiol groups were preactivated. The results from cytotoxicity studies demonstrated that Ch-EDTA-cys and Ch-EDTA-cys-2MNA were not toxic to the cells at the polymer test concentration of 0.25% (w/v) while cell viability decreased by increasing the concentration of Ch-EDTA. Although EDTA molecule was modified by thiolation and preactivation, approximately 50% of chelating properties of the conjugates were maintained compared to Ch-EDTA. Ch-EDTA-cys-2MNA adhered on freshly excised porcine intestinal mucosa up to 6h while Ch-EDTA adhered for just 1h. According to the combination of mucoadhesive and chelating properties of the conjugates synthesized in this study, Ch-EDTA-cys-2MNA might be useful for various mucosal drug delivery systems. Copyright © 2016 Elsevier B.V. All rights reserved.

  7. 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.

  8. Diketopyrrolopyrrole polymers for organic solar cells

    NARCIS (Netherlands)

    Li, Wei Wei; Hendriks, K.H.; Wienk, M.M.; Janssen, R.A.J.

    2016-01-01

    Conspectus Conjugated polymers have been extensively studied for application in organic solar cells. In designing new polymers, particular attention has been given to tuning the absorption spectrum, molecular energy levels, crystallinity, and charge carrier mobility to enhance performance. As a

  9. The Role of Molecular Structure and Conformation in Polymer Electronics

    NARCIS (Netherlands)

    von Hauff, Elizabeth

    2011-01-01

    ABSTRACT Conjugated polymers have unique material properties that make them promising for a wide range of applications. The potential lies in the virtually infinite possibilities for creating new materials for specific applications by simply chemically tuning the molecular structure. Conjugated

  10. Recent Advances in Wide-Bandgap Photovoltaic Polymers.

    Science.gov (United States)

    Cai, Yunhao; Huo, Lijun; Sun, Yanming

    2017-06-01

    The past decade has witnessed significant advances in the field of organic solar cells (OSCs). Ongoing improvements in the power conversion efficiency of OSCs have been achieved, which were mainly attributed to the design and synthesis of novel conjugated polymers with different architectures and functional moieties. Among various conjugated polymers, the development of wide-bandgap (WBG) polymers has received less attention than that of low-bandgap and medium-bandgap polymers. Here, we briefly summarize recent advances in WBG polymers and their applications in organic photovoltaic (PV) devices, such as tandem, ternary, and non-fullerene solar cells. Addtionally, we also dissuss the application of high open-circuit voltage tandem solar cells in PV-driven electrochemical water dissociation. We mainly focus on the molecular design strategies, the structure-property correlations, and the photovoltaic performance of these WBG polymers. Finally, we extract empirical regularities and provide invigorating perspectives on the future development of WBG photovoltaic materials. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Synthesis and functions of well-defined polymer-drug conjugates as efficient nanocarriers for intravesical chemotherapy of bladder cancer(a).

    Science.gov (United States)

    Yu, Qingsong; Zhang, Jiajing; Zhang, Guan; Gan, Zhihua

    2015-04-01

    Novel poly(ethylene glycol) and poly(N-(2-hydroxypropyl)methacrylamide) block copolymer (PEG-b-PHPMA) with well-defined composition was synthesized by RAFT polymerization. Folate and doxorubicin (DOX) were quantitatively introduced into the copolymer. The influences of folate content and pH value on folate receptor (FR) mediated cell endocytosis and pH-responsive DOX release were studied. It has been demonstrated that minimum folate content is needed for the enrichment of hydrophobic folate on the hydrophilic part of polymer conjugates. The cytotoxicity of targetable polymer drug conjugates was much higher than that of non-targetable ones and free DOX. It could be concluded that the folate plays a significant role in targeting and internalization of the conjugates against bladder cancer cells. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Polythiophenes Comprising Conjugated Pendants for Polymer Solar Cells: A Review

    Directory of Open Access Journals (Sweden)

    Hsing-Ju Wang

    2014-03-01

    Full Text Available Polythiophene (PT is one of the widely used donor materials for solution-processable polymer solar cells (PSCs. Much progress in PT-based PSCs can be attributed to the design of novel PTs exhibiting intense and broad visible absorption with high charge carrier mobility to increase short-circuit current density (Jsc, along with low-lying highest occupied molecular orbital (HOMO levels to achieve large open circuit voltage (Voc values. A promising strategy to tailor the photophysical properties and energy levels via covalently attaching electron donor and acceptor pendants on PTs backbone has attracted much attention recently. The geometry, electron-donating capacity, and composition of conjugated pendants are supposed to be the crucial factors in adjusting the conformation, energy levels, and photovoltaic performance of PTs. This review will go over the most recent approaches that enable researchers to obtain in-depth information in the development of PTs comprising conjugated pendants for PSCs.

  13. Developments in the chemistry and band gap engineering of donor-acceptor substituted conjugated polymers

    NARCIS (Netherlands)

    Mullekom, van H.A.M.; Vekemans, J.A.J.M.; Havinga, E.E.; Meijer, E.W.

    2001-01-01

    This paper reviews the tools to manipulate and minimize the band gap of conjugated (co)polymers. The effects of minimization of the bond length alternation and of the incorporation of donor-K-acceptor units are discussed in particular. A systematic study of a series of alternating donor-acceptor

  14. Application of optical phase conjugation to plasma diagnostics (invited)

    International Nuclear Information System (INIS)

    Jahoda, F.C.; Anderson, B.T.; Forman, P.R.; Weber, P.G.

    1985-01-01

    Several possibilities for plasma diagnostics provided by optical phase conjugation and, in particular, self-pumped phase conjugation in barium titanate (BaTiO 3 ) are discussed. These include placing a plasma within a dye laser cavity equipped with a phase conjugate mirror for intracavity absorption measurements, time differential refractometry with high spatial resolution, and simplified real-time holographic interferometry. The principles of phase conjugation with particular reference to photorefractive media and the special advantages of self-pumped phase conjugation are reviewed prior to the discussion of the applications. Distinctions are made in the applications between those for which photorefractive conjugators are essential and those for which they only offer experimental simplification relative to other types of phase conjugators

  15. Biomedical applications of polymers derived by reversible addition - fragmentation chain-transfer (RAFT).

    Science.gov (United States)

    Fairbanks, Benjamin D; Gunatillake, Pathiraja A; Meagher, Laurence

    2015-08-30

    RAFT- mediated polymerization, providing control over polymer length and architecture as well as facilitating post polymerization modification of end groups, has been applied to virtually every facet of biomedical materials research. RAFT polymers have seen particularly extensive use in drug delivery research. Facile generation of functional and telechelic polymers permits straightforward conjugation to many therapeutic compounds while synthesis of amphiphilic block copolymers via RAFT allows for the generation of self-assembled structures capable of carrying therapeutic payloads. With the large and growing body of literature employing RAFT polymers as drug delivery aids and vehicles, concern over the potential toxicity of RAFT derived polymers has been raised. While literature exploring this complication is relatively limited, the emerging consensus may be summed up in three parts: toxicity of polymers generated with dithiobenzoate RAFT agents is observed at high concentrations but not with polymers generated with trithiocarbonate RAFT agents; even for polymers generated with dithiobenzoate RAFT agents, most reported applications call for concentrations well below the toxicity threshold; and RAFT end-groups may be easily removed via any of a variety of techniques that leave the polymer with no intrinsic toxicity attributable to the mechanism of polymerization. The low toxicity of RAFT-derived polymers and the ability to remove end groups via straightforward and scalable processes make RAFT technology a valuable tool for practically any application in which a polymer of defined molecular weight and architecture is desired. Copyright © 2015. Published by Elsevier B.V.

  16. Photochemical stability of conjugated polymers, electron acceptors and blends for polymer solar cells resolved in terms of film thickness and absorbance

    DEFF Research Database (Denmark)

    Tromholt, Thomas; Vesterager Madsen, Morten; Carlé, Jon Eggert

    2012-01-01

    Photochemical degradation at 1 sun under AM1.5G illumination was performed on six conjugated polymers and five different electron acceptors. Additionally, the respective polymer:PC60BM and P3HT:electron acceptor blends were studied, and all degradations were resolved in terms of film thickness...... within each material group were found to vary for both the pure polymers and the blends. The stability ranking between the materials of the pure polymers was found to be similar to the ranking for their respective blends, implying that the photochemical stability of a pure polymer is a good measure...... of its associated blend stability. Different electron acceptors were found to stabilize P3HT decreasingly with decreasing donor–acceptor LUMO–LUMO gap. Destabilization of P3HT was observed in the case of the electron acceptor ICBA. Additionally, the decreased stabilization of P3HT by high LUMO electron...

  17. Charge transport in conjugated polymers: a multiscale picture

    Science.gov (United States)

    Ruehle, Victor; Kirkpatrick, James; Kremer, Kurt; Andrienko, Denis

    2009-03-01

    A framework to study charge transport in conjugated polymers using realistic morphologies is developed. First, the atomistic force field is refined using first-principles calculations. Systematic coarse graining is then performed to extend simulation times and system sizes accessible to molecular dynamics simulations. Material morphologies are generated using the coarse grained and atomistic models. Finally, the charge mobility is obtained using temperature activated hopping picture for charge transport [1]. The framework is tested on neutral and oxidized polypyrrole with different structural ordering [2]. [4pt] [1] J. Kirkpatrick, V. Marcon, J. Nelson, K. Kremer, D. Andrienko, Phys. Rev. Lett. 98, 227402 (2007)[0pt] [2] V. Ruehle, J. Kirkpatrick, K. Kremer, D. Andrienko, Phys. Stat. Solidi B, 245, 844 (2008)

  18. Star polymer-drug conjugates with pH-controlled drug release and carrier degradation

    Czech Academy of Sciences Publication Activity Database

    Kostková, Hana; Schindler, Lucie; Kotrchová, Lenka; Kovář, Marek; Šírová, Milada; Kostka, Libor; Etrych, Tomáš

    2017-01-01

    Roč. 2017, 3 January (2017), s. 1-10, č. článku 8675435. ISSN 1687-4110 R&D Projects: GA MŠk(CZ) LQ1604 Institutional support: RVO:61389013 ; RVO:61388971 Keywords : star conjugate * HPMA copolymer * doxorubicin Subject RIV: CD - Macromolecular Chemistry; EE - Microbiology, Virology (MBU-M) OBOR OECD: Polymer science; Microbiology (MBU-M) Impact factor: 1.871, year: 2016

  19. Charge transport behavior of benodithiophene-diketopyrrololpyrrole-based conjugated polymer in organic field-effect transistors

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jin Kuen [Dept. of Chemistry, Hankuk University of Foreign Studies, Yongin (Korea, Republic of)

    2015-07-15

    Organic optoelectronic devices, such as light-emitting diodes, organic solar cells (OSCs), and organic field effect transistors (OFETs), have emerged due to the development of π-conjugated polymers. Because the delocalized π-framework can significantly reduce the energy gap between the highest-occupied molecular orbital (HOMO) and the lowest-unoccupied molecular orbital (LUMO), their intrinsic optoelectronic properties can be tunable with their conjugation length in terms of average molecular weights and their π-backbone structures. The new type of low bandgap conjugated polymer (P1) has been successively polymerized via a palladium- catalyzed Stille cross-coupling reaction with bis-ethylhexyl BDT and bis-n-decane DPP. With a linear alkyl chain in the DPP units, the intermolecular packing structure was thought to be enhanced by proving the UV–Vis and UPS spectra. In addition, the electronic properties of P1 via field-effect transistors well illustrate the typical p-type semiconducting property without showing the significant improvement by thermal annealing. From a broader perspective, this research indicates that a wider choice of linear alkyl chain length in DPP units and modification of the interface between dielectric and active layers should be sought to further optimize device performance. Hence, progressive works with the strategy presented in this report will be pursued to address the different challenges in attaining target OFET performances.

  20. Clinically Relevant Anticancer Polymer Paclitaxel Therapeutics

    Directory of Open Access Journals (Sweden)

    Danbo Yang

    2010-12-01

    Full Text Available The concept of utilizing polymers in drug delivery has been extensively explored for improving the therapeutic index of small molecule drugs. In general, polymers can be used as polymer-drug conjugates or polymeric micelles. Each unique application mandates its own chemistry and controlled release of active drugs. Each polymer exhibits its own intrinsic issues providing the advantage of flexibility. However, none have as yet been approved by the U.S. Food and Drug Administration. General aspects of polymer and nano-particle therapeutics have been reviewed. Here we focus this review on specific clinically relevant anticancer polymer paclitaxel therapeutics. We emphasize their chemistry and formulation, in vitro activity on some human cancer cell lines, plasma pharmacokinetics and tumor accumulation, in vivo efficacy, and clinical outcomes. Furthermore, we include a short review of our recent developments of a novel poly(L-g-glutamylglutamine-paclitaxel nano-conjugate (PGG-PTX. PGG-PTX has its own unique property of forming nano-particles. It has also been shown to possess a favorable profile of pharmacokinetics and to exhibit efficacious potency. This review might shed light on designing new and better polymer paclitaxel therapeutics for potential anticancer applications in the clinic.

  1. Clinically Relevant Anticancer Polymer Paclitaxel Therapeutics

    International Nuclear Information System (INIS)

    Yang, Danbo; Yu, Lei; Van, Sang

    2010-01-01

    The concept of utilizing polymers in drug delivery has been extensively explored for improving the therapeutic index of small molecule drugs. In general, polymers can be used as polymer-drug conjugates or polymeric micelles. Each unique application mandates its own chemistry and controlled release of active drugs. Each polymer exhibits its own intrinsic issues providing the advantage of flexibility. However, none have as yet been approved by the U.S. Food and Drug Administration. General aspects of polymer and nano-particle therapeutics have been reviewed. Here we focus this review on specific clinically relevant anticancer polymer paclitaxel therapeutics. We emphasize their chemistry and formulation, in vitro activity on some human cancer cell lines, plasma pharmacokinetics and tumor accumulation, in vivo efficacy, and clinical outcomes. Furthermore, we include a short review of our recent developments of a novel poly(l-γ-glutamylglutamine)-paclitaxel nano-conjugate (PGG-PTX). PGG-PTX has its own unique property of forming nano-particles. It has also been shown to possess a favorable profile of pharmacokinetics and to exhibit efficacious potency. This review might shed light on designing new and better polymer paclitaxel therapeutics for potential anticancer applications in the clinic

  2. Clinically Relevant Anticancer Polymer Paclitaxel Therapeutics

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Danbo [Biomedical Engineering and Technology Institute, Institutes for Advanced Interdisciplinary Research, East China Normal University, 3663 North Zhongshan Road, Shanghai, 200062 (China); Yu, Lei, E-mail: yu-lei@gg.nitto.co.jp [Biomedical Engineering and Technology Institute, Institutes for Advanced Interdisciplinary Research, East China Normal University, 3663 North Zhongshan Road, Shanghai, 200062 (China); Biomedical Group, Nitto Denko Technical Corporation, 501 Via Del Monte, Oceanside, CA 92058 (United States); Van, Sang [Biomedical Group, Nitto Denko Technical Corporation, 501 Via Del Monte, Oceanside, CA 92058 (United States)

    2010-12-23

    The concept of utilizing polymers in drug delivery has been extensively explored for improving the therapeutic index of small molecule drugs. In general, polymers can be used as polymer-drug conjugates or polymeric micelles. Each unique application mandates its own chemistry and controlled release of active drugs. Each polymer exhibits its own intrinsic issues providing the advantage of flexibility. However, none have as yet been approved by the U.S. Food and Drug Administration. General aspects of polymer and nano-particle therapeutics have been reviewed. Here we focus this review on specific clinically relevant anticancer polymer paclitaxel therapeutics. We emphasize their chemistry and formulation, in vitro activity on some human cancer cell lines, plasma pharmacokinetics and tumor accumulation, in vivo efficacy, and clinical outcomes. Furthermore, we include a short review of our recent developments of a novel poly(l-γ-glutamylglutamine)-paclitaxel nano-conjugate (PGG-PTX). PGG-PTX has its own unique property of forming nano-particles. It has also been shown to possess a favorable profile of pharmacokinetics and to exhibit efficacious potency. This review might shed light on designing new and better polymer paclitaxel therapeutics for potential anticancer applications in the clinic.

  3. Planar-Processed Polymer Transistors.

    Science.gov (United States)

    Xu, Yong; Sun, Huabin; Shin, Eul-Yong; Lin, Yen-Fu; Li, Wenwu; Noh, Yong-Young

    2016-10-01

    Planar-processed polymer transistors are proposed where the effective charge injection and the split unipolar charge transport are all on the top surface of the polymer film, showing ideal device characteristics with unparalleled performance. This technique provides a great solution to the problem of fabrication limitations, the ambiguous operating principle, and the performance improvements in practical applications of conjugated-polymer transistors. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Effect of interchain coupling on the excited polaron in conjugated polymers

    International Nuclear Information System (INIS)

    Li, Xiao-xue; Chen, Gang

    2017-01-01

    Based on the one-dimensional extended Su–Schrieffer–Heeger model, we theoretically investigate the effect of interchain coupling on the formation and polarization of the single-excited state of polaron in conjugated polymers. It is found that there exists a turnover value of the coupling strength, over which the excited polaron could not be formed in either of the two coupled chains. Instead, a polaron-like particle is localized at the center of each chain. In addition, we also find that the reverse polarization of the excited polaron could be enhanced for some cases in polymer when the interchain coupling becomes strong until it exceeds the critical value. - Highlights: • Effect of interchain coupling on the single-excited state of polaron is studied. • When coupling strength exceeds critical value, the excited polaron is dissociated. • Soliton pair could be dissociated into polaron-like particle with strong coupling. • Reverse polarization of excited polaron is enhanced by weak interchain coupling. • Reverse polarization is obtained more easily in solid film of polymer molecules.

  5. Effect of interchain coupling on the excited polaron in conjugated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Li, Xiao-xue, E-mail: sps_lixx@ujn.edu.cn; Chen, Gang, E-mail: ss_cheng@ujn.edu.cn

    2017-02-05

    Based on the one-dimensional extended Su–Schrieffer–Heeger model, we theoretically investigate the effect of interchain coupling on the formation and polarization of the single-excited state of polaron in conjugated polymers. It is found that there exists a turnover value of the coupling strength, over which the excited polaron could not be formed in either of the two coupled chains. Instead, a polaron-like particle is localized at the center of each chain. In addition, we also find that the reverse polarization of the excited polaron could be enhanced for some cases in polymer when the interchain coupling becomes strong until it exceeds the critical value. - Highlights: • Effect of interchain coupling on the single-excited state of polaron is studied. • When coupling strength exceeds critical value, the excited polaron is dissociated. • Soliton pair could be dissociated into polaron-like particle with strong coupling. • Reverse polarization of excited polaron is enhanced by weak interchain coupling. • Reverse polarization is obtained more easily in solid film of polymer molecules.

  6. Hybrid fluorescent nanoparticles fabricated from pyridine-functionalized polyfluorene-based conjugated polymer as reversible pH probes over a broad range of acidity-alkalinity

    International Nuclear Information System (INIS)

    Cui, Haijun; Chen, Ying; Li, Lianshan; Tang, Zhiyong; Wu, Yishi; Fu, Hongbing; Tian, Zhiyuan

    2014-01-01

    Conjugated polymer nanoparticles (CPNs) were developed based on a polyfluorene-based conjugated polymer with thiophene units carrying pyridyl moieties incorporated in the backbone of polymer chains (PFPyT). Hybrid CPNs fabricated from PFPyT and an amphiphilic polymer (NP1) displayed pH-sensitive fluorescence emission features in the range from pH 4.8 to 13, which makes them an attractive nanomaterial for wide range optical sensing of pH values. The fluorescence of hybrid CPNs based on chemically close polyfluorene derivatives without pyridyl moieties (NP3), in contrast, remains virtually unperturbed by pH values in the same range. The fluorescence emission features of NP1 underwent fully reversible changes upon alternating acidification/basification of aqueous dispersions of the CPNs and also displayed excellent repeatability. The observed pH sensing properties of NP1 are attributed to protonation/deprotonation of the nitrogen atoms of the pyridine moieties. This, in turn, leads to the redistribution of electron density of pyridine moieties and their participation in the π-conjugation within the polymer main chains. The optically transparent amphiphilic polymers also exerted significant influence on the pH sensing features of the CPNs, likely by acting as proton sponge and/or acid chaperone. (author)

  7. Hopping approach towards exciton dissociation in conjugated polymers

    International Nuclear Information System (INIS)

    Emelianova, E. V.; Auweraer, M. van der; Baessler, H.

    2008-01-01

    By employing random walk an analytic theory for the dissociation of singlet excitons in a random organic solid, for instance, a conjugated polymer, has been developed. At variance of conventional three-dimensional Onsager theory, it is assumed that an exciton with finite lifetime can first transfer endothermically an electron to an adjacent site, thereby generating a charge transfer state whose energy is above the energy of that of the initial exciton. In a second step the latter can fully dissociate in accordance with Onsager's concept Brownian motion. The results indicate that, depending of the energy required for the first jump, the first jump contributes significantly to the field dependence of the dissociation yield. Disorder weakens the temperature dependence of the yield dramatically and precludes extracting information on the exciton binding energy from it

  8. HPMA copolymer-based polymer conjugates for the delivery and controlled release of retinoids

    Czech Academy of Sciences Publication Activity Database

    Lidický, Ondřej; Šírová, Milada; Etrych, Tomáš

    2016-01-01

    Roč. 65, Suppl. 2 (2016), S233-S241 ISSN 0862-8408 R&D Projects: GA MŠk(CZ) LQ1604 Institutional support: RVO:61389013 ; RVO:61388971 Keywords : polymer conjugate * retinoid * HPMA Subject RIV: EB - Genetics ; Molecular Biology; EA - Cell Biology (MBU-M) Impact factor: 1.461, year: 2016 http://www.biomed.cas.cz/physiolres/pdf/65%20Suppl%202/65_S233.pdf

  9. Single-Molecule Luminescence and High Efficiency Photovoltaic Cells Based on Percolated Conducting Carbon Nanotubes Scaffolds Templated with Light-Harvesting Conjugated Polymers and Nanohybrids

    National Research Council Canada - National Science Library

    Yang, Arnold C

    2009-01-01

    .... Nanocomposites constructed by surface-grafted multiwall carbon nanotubes (CNTs) with conjugated polymers dispersed in a polymer matrix were synthesized to form novel optoelectronic materials that exploit single-molecule effects...

  10. Effect of side chain length on charge transport, morphology, and photovoltaic performance of conjugated polymers in bulk heterojunction solar cells

    NARCIS (Netherlands)

    Duan, C.; Willems, R.E.M.; van Franeker, J.J.; Bruijnaers, B.J.; Wienk, M.M.; Janssen, R.A.J.

    2016-01-01

    The effect of side chain length on the photovoltaic properties of conjugated polymers is systematically investigated with two sets of polymers that bear different alkyl side chain lengths based on benzodithiophene and benzo[2,1,3]thiadiazole or 5,6-difluorobenzo[2,1,3]thiadiazole. Characterization

  11. Development and validation of an in vitro pharmacokinetic/pharmacodynamic model to test the antibacterial efficacy of antibiotic polymer conjugates.

    Science.gov (United States)

    Azzopardi, Ernest A; Ferguson, Elaine L; Thomas, David W

    2015-04-01

    This study describes the use of a novel, two-compartment, static dialysis bag model to study the release, diffusion, and antibacterial activity of a novel, bioresponsive dextrin-colistin polymer conjugate against multidrug resistant (MDR) wild-type Acinetobacter baumannii. In this model, colistin sulfate, at its MIC, produced a rapid and extensive drop in viable bacterial counts (growth for up to 48 h, with 3 log10 CFU/ml lower bacterial counts after 48 h than those of controls. Doubling the concentration of dextrin-colistin conjugate (to 2× MIC) led to an initial bacterial killing of 3 log10 CFU/ml at 8 h, with a similar regrowth profile to 1× MIC treatment thereafter. The addition of colistin sulfate (1× MIC) to dextrin-colistin conjugate (1× MIC) resulted in undetectable bacterial counts after 4 h, followed by suppressed bacterial growth (3.5 log10 CFU/ml lower than that of control at 48 h). Incubation of dextrin-colistin conjugates with infected wound exudate from a series of burn patients (n = 6) revealed an increasing concentration of unmasked colistin in the outer compartment (OC) over time (up to 86.3% of the initial dose at 48 h), confirming that colistin would be liberated from the conjugate by endogenous α-amylase within the wound environment. These studies confirm the utility of this model system to simulate the pharmacokinetics of colistin formation in humans administered dextrin-colistin conjugates and further supports the development of antibiotic polymer conjugates in the treatment of MDR infections. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  12. Modelling of charge carrier transport in conjugated polymers doped by polar additives

    Czech Academy of Sciences Publication Activity Database

    Toman, Petr; Nešpůrek, Stanislav; Bartkowiak, W.

    2009-01-01

    Roč. 27, č. 3 (2009), s. 797-812 ISSN 0137-1339. [International Conference on Electrical and Related Properties of Organic Solids /11./. Piechowice, 13.07.2008-17.07.2008] R&D Projects: GA ČR GA203/06/0285; GA AV ČR KAN400720701; GA MŠk MEB050815 Institutional research plan: CEZ:AV0Z40500505 Keywords : conjugated polymers * charge carrier transport * molecular electronics Subject RIV: CD - Macromolecular Chemistry Impact factor: 0.384, year: 2009

  13. Pronounced Side Chain Effects in Triple Bond-Conjugated Polymers Containing Naphthalene Diimides for n-Channel Organic Field-Effect Transistors

    KAUST Repository

    Nam, Sungho

    2018-03-23

    Three triple bond-conjugated naphthalene diimide (NDI) copolymers, poly{[N,N′-bis(2-R1)-naphthalene-1,4,5,8-bis(dicarboximide)-2,6-diyl]-alt-[(2,5-bis(2-R2)-1,4-phenylene)bis(ethyn-2,1-diyl)]} (PNDIR1-R2), were synthesized via Sonogashira coupling polymerization with varying alkyl side chains at the nitrogen atoms of the imide ring and 2,5-positions of the 1,4-diethynylbenzene moiety. Considering their identical polymer backbone structures, the side chains were found to have a strong influence on the surface morphology/nanostructure, thus playing a critical role in charge-transporting properties of the three NDI-based copolymers. Among the polymers, the one with an octyldodecyl (OD) chain at the nitrogen atoms of imide ring and a hexadecyloxy (HO) chain at the 2,5-positions of 1,4-diethynylbenzene, P(NDIOD-HO), exhibited the highest electron mobility of 0.016 cm2 V–1 s–1, as compared to NDI-based copolymers with an ethylhexyl chain at the 2,5-positions of 1,4-diethynylbenzene. The enhanced charge mobility in the P(NDIOD-HO) layers is attributed to the well-aligned nano-fiber-like surface morphology and highly ordered packing structure with a dominant edge-on orientation, thus enabling efficient in-plane charge transport. Our results on the molecular structure–charge transport property relationship in these materials may provide an insight into novel design of n-type conjugated polymers for applications in the organic electronics of the future.

  14. Microfluidic Fabrication of Conjugated Polymer Sensor Fibers

    Energy Technology Data Exchange (ETDEWEB)

    Yoo, Imsung; Song, Simon [Hanyang University, Seoul (Korea, Republic of)

    2014-10-15

    We propose a fabrication method for polydiacetylene (PDA)-embedded hydrogel microfibers on a microfluidic chip. These fibers can be applied to the detection of cyclodextrines (CDs), which are a family of sugar and aluminum ions. PDA, a family of conjugated polymers, has unique characteristics when used for a sensor, because it undergoes a blue-to-red color transition and nonfluorescence-to-fluorescence transition in response to environmental stimulation. PDAs have different sensing characteristics depending on the head group of PCDA. By taking advantage of ionic crosslinking-induced hydrogel formation and the 3D hydrodynamic focusing effect on a microfluidic chip, PCDA-EDEA-derived diacetylene (DA) monomer-embedded microfibers were successfully fabricated. UV irradiation of the fibers afforded blue-colored PDA, and the resulting blue PDA fibers underwent a phase transition to red and emitted red fluorescence upon exposure to CDs and aluminum ions. Their fluorescence intensity varied depending on the CDs and aluminum ion concentrations. This phase transition was also observed when the fibers were dried.

  15. Interplay of alternative conjugated pathways and steric interactions on the electronic and optical properties of donor-acceptor conjugated polymers

    KAUST Repository

    Lima, Igo T.; Risko, Chad; Aziz, Saadullah Gary; Da Silva Filho, Demé trio A Da Silva; Bredas, Jean-Luc

    2014-01-01

    Donor-acceptor π-conjugated copolymers are of interest for a wide range of electronic applications, including field-effect transistors and solar cells. Here, we present a density functional theory (DFT) study of the impact of varying the conjugation pathway on the geometric, electronic, and optical properties of donor-acceptor systems. We consider both linear ("in series"), traditional conjugation among the donor-acceptor moieties versus structures where the acceptor units are appended orthogonally to the linear, donor-only conjugated backbone. Long-range-corrected hybrid functionals are used in the investigation with the values of the tuned long-range separation parameters providing an estimate of the extent of conjugation as a function of the oligomer architecture. Considerable differences in the electronic and optical properties are determined as a function of the nature of the conjugation pathway, features that should be taken into account in the design of donor-acceptor copolymers.

  16. BEAM applications to polymer materials

    International Nuclear Information System (INIS)

    Tagawa, Seiichi

    1994-01-01

    Recently papers about beam applications to polymers have been increasing rapidly both in the fundamental and applied fields. Fairly large number of papers have been published in the fundamental aspects of radiation effects of beam applications to polymers such as pulse radiolysis and high density electronic excitation effects. A number of papers have been published in the more applied aspects of beam applications to polymers such as radiation processing and curing. The present paper describes recent beam applications to polymers. 1. Radiation Effects on Polymers; Radiation effects on polymers have been studied for more than 40 years. Most of work on radiation effects on polymers has been carried out by using high energy photon (gamma-ray) and electron beams, since polymers are sensitive to any kinds of ionizing radiation. Even non-ionizing radiation such as ultraviolet and visible light excites electronic excited states of polymers and then photo-chemical reactions of polymers are induced from the electronic excited states. Studies on radiation effects of other ionizing radiation on polymers have not been so popular for a long time. Recently application of new radiation such as ion beams to polymers have been worthy of remark in fields of advanced science and technology, since new radiation beams induce different radiation effects from those induced by high energy gamma-rays and electrons. 2. Beam Applications of Polymers; Recent progress in beam applications to polymers such as radiation processing and curing, x-ray and electron beam microlithography, and applications of new beams such as ion beams to polymers has been reviewed. (author)

  17. Fluorinated arene, imide and unsaturated pyrrolidinone based donor acceptor conjugated polymers: Synthesis, structure-property and device studies

    Science.gov (United States)

    Liyanage, Arawwawala Don Thilanga

    After the discovery of doped polyacetylene, organic semiconductor materials are widely studied as high impending active components in consumer electronics. They have received substantial consideration due to their potential for structural tailoring, low cost, large area and mechanically flexible alternatives to common inorganic semiconductors. To acquire maximum use of these materials, it is essential to get a strong idea about their chemical and physical nature. Material chemist has an enormous role to play in this novel area, including development of efficient synthetic methodologies and control the molecular self-assembly and (opto)-electronic properties. The body of this thesis mainly focuses on the substituent effects: how different substituents affect the (opto)-electronic properties of the donor-acceptor (D-A) conjugated polymers. The main priority goes to understand, how different alkyl substituent effect to the polymer solubility, crystallinity, thermal properties (e.g.: glass transition temperature) and morphological order. Three classes of D-A systems were extensively studied in this work. The second chapter mainly focuses on the synthesis and structure-property study of fluorinated arene (TFB) base polymers. Here we used commercially available 1,4-dibromo-2,3,5,6-tetrafluorobenzene (TFB) as the acceptor material and prepare several polymers using 3,3'-dialkyl(3,3'-R2T2) or 3,3'-dialkoxy bithiophene (3,3'-RO2T2) units as electron donors. A detail study was done using 3,3'-bithiophene donor units incorporating branched alkoxy-functionalities by systematic variation of branching position and chain length. The study allowed disentangling the branching effects on (i) aggregation tendency, intermolecular arrangement, (iii) solid state optical energy gaps, and (iv) electronic properties in an overall consistent picture, which might guide future polymer synthesis towards optimized materials for opto-electronic applications. The third chapter mainly focused on

  18. Theory of even-parity states and two-photon spectra of conjugated polymers

    Science.gov (United States)

    McWilliams, P. C. M.; Hayden, G. W.; Soos, Z. G.

    1991-04-01

    The two-photon absorption (TPA) spectrum of interacting π electrons in conjugated polymers is shown to be qualitatively different from any single-particle description, including the Hartree-Fock limit. Alternating transfer integrals t(1+/-δ) along the backbone lead to a weak TPA below the one-photon gap Eg for arbitrarily weak correlations at δ=0, for intermediate correlations at δ=0.07 in polyenes, and for strong correlations at any δtheory to Eg in the limit of strong correlations in Hubbard models and is around 1.5Eg for Pariser-Parr-Pople (PPP) parameters. The PPP model, which accounts for one- and two-photon excitations of finite polyenes, is extended to even-parity states in polydiacetylenes (PDA's), polyacetylene (PA), and polysilanes (PS's). Previous experimental data for PDA and PS support both the strong TPA above Eg and weak TPA slightly below Eg for δ=0.15 in PDA and above Eg for δ~0.3 in PS. The strong TPA expected around 1.5Eg in isolated PA strands shifts to ~Eg due to interchain π-electron dispersion forces. TPA intensities in correlated states are shown to reflect both ionicity and mean-square charge separation. The even-parity states of conjugated polymers, like those of polyenes, show qualitatively different features associated with electron-electron correlations.

  19. Recent advances in polymer solar cells: realization of high device performance by incorporating water/alcohol-soluble conjugated polymers as electrode buffer layer.

    Science.gov (United States)

    He, Zhicai; Wu, Hongbin; Cao, Yong

    2014-02-01

    This Progress Report highlights recent advances in polymer solar cells with special attention focused on the recent rapid-growing progress in methods that use a thin layer of alcohol/water-soluble conjugated polymers as key component to obtain optimized device performance, but also discusses novel materials and device architectures made by major prestigious institutions in this field. We anticipate that due to drastic improvements in efficiency and easy utilization, this method opens up new opportunities for PSCs from various material systems to improve towards 10% efficiency, and many novel device structures will emerge as suitable architectures for developing the ideal roll-to-roll type processing of polymer-based solar cells. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Thickness dependent structural ordering, degradation and metastability in polysilane thin films: A photoluminescence study on representative σ-conjugated polymers

    International Nuclear Information System (INIS)

    Urbánek, Pavel; Kuřitka, Ivo

    2015-01-01

    We present a fundamental experimental study based on the fluorescence investigation of thin σ-conjugated polymer films, where the dependence of optoelectrical properties and UV degradation on film thickness ranging from nano- to microscale was studied. Such extensive and detailed study was performed for the first time and observed spectral shifts in emission and excitation spectra and UV degradation retardation point towards the conclusions that there exists a threshold thickness where the material degradation behavior, electron delocalization and structure suddenly change. The development of well aligned polymeric chain structure between the nano- and micrometer thickness (on the mesoscale) was shown responsible for the manifested phenomena. The material thicker than critical 500 nm has extremely small Stokes' shift, maximum extended σ-delocalization along the silicon polymer backbone and exhibits remarkable UV degradation slowdown and self-recovery ability. On the contrary, the electronic properties of thin films below 80 nm resemble those of random coils in solutions. The films of moderate thickness show relatively steep transition between these two modes of structural ordering and resulting properties. Altogether, we consider this complex phenomenon as a consequence of the mesoscale effect, which is an only recently introduced concept in polymer thin films. - Highlights: • Photoluminescence was used as a tool for structural investigation of polysilanes. • Primary study of strong dependence of thin polymer film structure on mesoscale. • A mesoscale effect observed for the first time on sigma conjugated polymers. • Conjugation length is dramatically extended in thicker films than in nanoscale. • Self-recovery effect was shown to be dependent on the mesoscale as well.

  1. Tunable Semiconducting Polymer Nanoparticles with INDT-Based Conjugated Polymers for Photoacoustic Molecular Imaging.

    Science.gov (United States)

    Stahl, Thomas; Bofinger, Robin; Lam, Ivan; Fallon, Kealan J; Johnson, Peter; Ogunlade, Olumide; Vassileva, Vessela; Pedley, R Barbara; Beard, Paul C; Hailes, Helen C; Bronstein, Hugo; Tabor, Alethea B

    2017-06-21

    Photoacoustic imaging combines both excellent spatial resolution with high contrast and specificity, without the need for patients to be exposed to ionizing radiation. This makes it ideal for the study of physiological changes occurring during tumorigenesis and cardiovascular disease. In order to fully exploit the potential of this technique, new exogenous contrast agents with strong absorbance in the near-infrared range, good stability and biocompatibility, are required. In this paper, we report the formulation and characterization of a novel series of endogenous contrast agents for photoacoustic imaging in vivo. These contrast agents are based on a recently reported series of indigoid π-conjugated organic semiconductors, coformulated with 1,2-dipalmitoyl-sn-glycero-3-phosphocholine, to give semiconducting polymer nanoparticles of about 150 nm diameter. These nanoparticles exhibited excellent absorption in the near-infrared region, with good photoacoustic signal generation efficiencies, high photostability, and extinction coefficients of up to three times higher than those previously reported. The absorption maximum is conveniently located in the spectral region of low absorption of chromophores within human tissue. Using the most promising semiconducting polymer nanoparticle, we have demonstrated wavelength-dependent differential contrast between vasculature and the nanoparticles, which can be used to unambiguously discriminate the presence of the contrast agent in vivo.

  2. Control of charge carrier dynamics in disordered conjugated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Hertel, Dirk [Physical Chemistry, University of Cologne, Luxemburgerstr. 116, 50939 Cologne, Germany, (Germany)

    2011-07-01

    We developed a new method to probe charge carrier mobility on ultrafast time scale. It is based on electric field induced second harmonic generation. The method is applied to prototypical amorphous conjugated polymers of the polyphenylene- and polyfluorene-type. Typically the carrier mobility in these organic polymers decreases with time in a power law fashion from about 1 cm{sup 2}Vs{sup -1} at 1 ps to its stationary value of about 10{sup -6} cm{sup 2}Vs{sup -1} in hundreds of ns. The dynamics of the mobility is discussed. It is shown, that in nanoscale devices the macroscopic mobility is not adequate to describe charge transport. We study the influence of disorder, morphology and temperature on ultrafast transport. At early times the transport is dominated by tunneling and disorder plays already an essential role. Comparison of transient photocurrents with Monte-Carlo simulation reveals that on-chain transport has to be invoked to rationalize our results. The hopping rates for intrachain transport are much larger compared with interchain transport. The results give access to essential transport properties for the development of advanced theoretical models and may help to design improved solar cells.

  3. The Influence of Conjugated Polymer Side Chain Manipulation on the Efficiency and Stability of Polymer Solar Cells

    DEFF Research Database (Denmark)

    Heckler, Ilona Maria; Kesters, Jurgen; Defour, Maxime

    2016-01-01

    ]thiazole (TzTz) acceptor units, were selected toward effective device scalability by roll-coating. The influence of the partial exchange (5% or 10%) of the solubilizing 2-hexyldecyloxy by alternative 2-phenylethoxy groups on efficiency and stability was investigated. With an increasing 2-phenylethoxy ratio...... studies under constant sun irradiance showed a diminishing initial degradation rate for the BT-based devices upon including the alternative side chains, whereas the (more stable) TzTz-based devices degraded at a faster rate from the start of the experiment upon partly exchanging the side chains. No clear......The stability of polymer solar cells (PSCs) can be influenced by the introduction of particular moieties on the conjugated polymer side chains. In this study, two series of donor-acceptor copolymers, based on bis(thienyl)dialkoxybenzene donor and benzo[c][1,2,5]thiadiazole (BT) or thiazolo[5,4-d...

  4. Hepatoma targeting peptide conjugated bio-reducible polymer complexed with oncolytic adenovirus for cancer gene therapy.

    Science.gov (United States)

    Choi, Joung-Woo; Kim, Hyun Ah; Nam, Kihoon; Na, Youjin; Yun, Chae-Ok; Kim, SungWan

    2015-12-28

    Despite adenovirus (Ad) vector's numerous advantages for cancer gene therapy, such as high ability of endosomal escape, efficient nuclear entry mechanism, and high transduction, and therapeutic efficacy, tumor specific targeting and antiviral immune response still remain as a critical challenge in clinical setting. To overcome these obstacles and achieve cancer-specific targeting, we constructed tumor targeting bioreducible polymer, an arginine grafted bio-reducible polymer (ABP)-PEG-HCBP1, by conjugating PEGylated ABP with HCBP1 peptides which has high affinity and selectivity towards hepatoma. The ABP-PEG-HCBP1-conjugated replication incompetent GFP-expressing ad, (Ad/GFP)-ABP-PEG-HCBP1, showed a hepatoma cancer specific uptake and transduction compared to either naked Ad/GFP or Ad/GFP-ABP. Competition assays demonstrated that Ad/GFP-ABP-PEG-HCBP1-mediated transduction was specifically inhibited by HCBP1 peptide rather than coxsackie and adenovirus receptor specific antibody. In addition, ABP-PEG-HCBP1 can protect biological activity of Ad against serum, and considerably reduced both innate and adaptive immune response against Ad. shMet-expressing oncolytic Ad (oAd; RdB/shMet) complexed with ABP-PEG-HCBP1 delivered oAd efficiently into hepatoma cancer cells. The oAd/ABP-PEG-HCBP1 demonstrated enhanced cancer cell killing efficacy in comparison to oAd/ABP complex. Furthermore, Huh7 and HT1080 cancer cells treated with oAd/shMet-ABP-PEG-HCBP1 complex had significantly decreased Met and VEGF expression in hepatoma cancer, but not in non-hepatoma cancer. In sum, these results suggest that HCBP1-conjugated bioreducible polymer could be used to deliver oncolytic Ad safely and efficiently to treat hepatoma. Copyright © 2015 Elsevier B.V. All rights reserved.

  5. Amplified spontaneous emission from the exciplex state of a conjugated polymer "PFO" in oleic acid

    Science.gov (United States)

    Idriss, Hajo; Taha, Kamal K.; Aldaghri, O.; Alhathlool, R.; AlSalhi, M. S.; Ibnaouf, K. H.

    2016-09-01

    The amplified spontaneous emission (ASE) characteristics of a conjugated polymer poly (9, 9-dioctylfluorenyl-2, 7-diyl) (PFO) in oleic acid have been studied under different concentrations and temperatures. Here, the ASE spectra of PFO in oleic acid have been obtained using a transverse cavity configuration where the conjugated PFO was pumped by laser pulses from the third harmonic of Nd: YAG laser (355 nm). The PFO in oleic acid produces ASE from an exciplex state - a new molecular species. The obtained results were compared with the PFO in benzene. Such ASE spectra from the exciplex state have not been observed for the PFO in benzene.

  6. Roughening Conjugated Polymer Surface for Enhancing the Charge Collection Efficiency of Sequentially Deposited Polymer/Fullerene Photovoltaics

    Directory of Open Access Journals (Sweden)

    Yoonhee Jang

    2015-08-01

    Full Text Available A method that enables the formation of a rough nano-scale surface for conjugated polymers is developed through the utilization of a polymer chain ordering agent (OA. 1-Chloronaphthalene (1-CN is used as the OA for the poly(3-hexylthiophene-2,5-diyl (P3HT layer. The addition of 1-CN to the P3HT solution improves the chain ordering of the P3HT during the film formation process and increases the surface roughness of the P3HT film compared to the film prepared without 1-CN. The roughened surface of the P3HT film is utilized to construct a P3HT/fullerene bilayer organic photovoltaic (OPV by sequential solution deposition (SqSD without thermal annealing process. The power conversion efficiency (PCE of the SqSD-processed OPV utilizing roughened P3HT layer is 25% higher than that utilizing a plain P3HT layer. It is revealed that the roughened surface of the P3HT increases the heterojunction area at the P3HT/fullerene interface and this resulted in improved internal charge collection efficiency, as well as light absorption efficiency. This method proposes a novel way to improve the PCE of the SqSD-processed OPV, which can be applied for OPV utilizing low band gap polymers. In addition, this method allows for the reassessment of polymers, which have shown insufficient performance in the BSD process.

  7. Functionalized conjugated polyelectrolytes design and biomedical applications

    CERN Document Server

    Wang, Shu

    2014-01-01

    Functionalized Conjugated Polyelectrolytes presents a comprehensive review of these polyelectrolytes and their biomedical applications. Basic aspects like molecular design and optoelectronic properties are covered in the first chapter. Emphasis is placed on the various applications including sensing (chemical and biological), disease diagnosis, cell imaging, drug/gene delivery and disease treatment. This book explores a multi-disciplinary topic of interest to researchers working in the fields of chemistry, materials, biology and medicine. It also offers an integrated perspective on both basic research and application issues. Functionalized conjugated polyelectrolyte materials, which have already drawn considerable interest, will become a major new direction for biomedicine development.

  8. Correlations between structure and optoelectronic properties of conjugated polymers

    International Nuclear Information System (INIS)

    Sims, Marc

    2002-01-01

    An understanding of the fundamental processes that govern the electro-optical properties of conjugated polymers is essential for the improvement of polymer light-emitting diodes (PLEDs). The majority of the work in this thesis comprises a study on a group of sterically congested poly(para-phenylenevinylene)s (PPVs). It deals initially with the discovery and development of a highly ordered crystalline phase of a chloro-derived n-butyl analogue. A thorough structural characterisation of this phase is then made from the results of X-ray Diffraction, FT-IR and Raman scattering spectroscopies. The effective conjugation length of the chains that comprise the crystalline sample is longer than that found in two relatively disordered films, one that was prepared by spin-coating and the other by drop-casting. The spin-coated film was found to exhibit a higher photoluminescence quantum efficiency (PLQE) value than the drop-cast film, which has been attributed to the presence of lower density of aggregate states in the former. The PLQE of the crystalline sample is considerably lower than that of both of the films and this is ascribed to the rapid migration of excitons to defect sites e.g. grain boundaries. PLE measurements for all the samples strongly suggest that singlet exciton quenching is intimately related to energy migration processes. Through the study of a novel, reversible, light-induced photoluminescence quenching effect, it was concluded that photogenerated polaronic species can be trapped sufficiently deeply that they can stabilise for periods in excess of hours at low temperatures. Furthermore, it is demonstrated that the photogenerated polaronic species are less stable in the crystalline sample, yet most stable in the most disordered spin-cast film. It is shown by excitation into the tail states of the crystalline sample that the first vibronic feature in the quasi-resonantly excited PL spectrum undergoes gain. This phenomenon is not observed in the more

  9. Synthesis of metalloporphyrin-based conjugated microporous polymer spheres directed by bipyridine-type ligands.

    Science.gov (United States)

    Ji, Guipeng; Yang, Zhenzhen; Zhao, Yanfei; Zhang, Hongye; Yu, Bo; Xu, Jilei; Xu, Huanjun; Liu, Zhimin

    2015-04-30

    Zinc porphyrin (TP-Zn)-based conjugated microporous polymer (Zn-CMP) spheres were obtained via Sonagashira-Hagihara cross coupling reactions between 5,10,15,20-tetrakis(4-ethynylphenyl)porphyrin-Zn(II) and brominated monomers directed by bidentate bipyridine (BP)-type ligands for the first time, and the sphere diameters could be adjusted from 320 to 740 nm. The coordination between BP and TP-Zn was proved to be the key to forming spheres.

  10. Photoinduced charge and energy transfer in dye-doped conjugated polymers

    International Nuclear Information System (INIS)

    Veldman, Dirk; Bastiaansen, Jolanda J.A.M.; Langeveld-Voss, Bea M.W.; Sweelssen, Joergen; Koetse, Marc M.; Meskers, Stefan C.J.; Janssen, Rene A.J.

    2006-01-01

    Conjugated polymer-molecular dye blends of MDMO-PPV (poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene]) and PF1CVTP (poly[9,9-dioctylfluorene-2,7-diyl-alt-2,5-bis(2-thienyl-1-cyanovinyl) -1-(3',7= '-dimethyloctyloxy)-4-methoxybenzene-5'',5''-diyl]) with three dipyrrometheneboron difluoride (bodipy) dyes were studied by (time-resolved) fluorescence and photoinduced absorption spectroscopy to determine quantitatively the relation between the electronic HOMO and LUMO levels and the occurrence of energy or charge transfer after optical excitation. We find that for MDMO-PPV photoinduced charge transfer to the dyes occurs, while photoexcitation of PF1CVTP exclusively results in energy transfer. The differences can be rationalized by assuming that the energy of the charge separated state is 0.33-0.45 eV higher than the energy determined from oxidation and reduction potentials of donor and acceptor, respectively. This provides an important design rule to identify appropriate materials for polymer solar cells that can have a high open-circuit voltage

  11. The Influence of Conjugated Polymer Side Chain Manipulation on the Efficiency and Stability of Polymer Solar Cells.

    Science.gov (United States)

    Heckler, Ilona M; Kesters, Jurgen; Defour, Maxime; Madsen, Morten V; Penxten, Huguette; D'Haen, Jan; Van Mele, Bruno; Maes, Wouter; Bundgaard, Eva

    2016-03-09

    The stability of polymer solar cells (PSCs) can be influenced by the introduction of particular moieties on the conjugated polymer side chains. In this study, two series of donor-acceptor copolymers, based on bis(thienyl)dialkoxybenzene donor and benzo[ c ][1,2,5]thiadiazole (BT) or thiazolo[5,4- d ]thiazole (TzTz) acceptor units, were selected toward effective device scalability by roll-coating. The influence of the partial exchange (5% or 10%) of the solubilizing 2-hexyldecyloxy by alternative 2-phenylethoxy groups on efficiency and stability was investigated. With an increasing 2-phenylethoxy ratio, a decrease in solar cell efficiency was observed for the BT-based series, whereas the efficiencies for the devices based on the TzTz polymers remained approximately the same. The photochemical degradation rate for PSCs based on the TzTz polymers decreased with an increasing 2-phenylethoxy ratio. Lifetime studies under constant sun irradiance showed a diminishing initial degradation rate for the BT-based devices upon including the alternative side chains, whereas the (more stable) TzTz-based devices degraded at a faster rate from the start of the experiment upon partly exchanging the side chains. No clear trends in the degradation behavior, linked to the copolymer structural changes, could be established at this point, evidencing the complex interplay of events determining PSCs' lifetime.

  12. The Influence of Conjugated Polymer Side Chain Manipulation on the Efficiency and Stability of Polymer Solar Cells

    Directory of Open Access Journals (Sweden)

    Ilona M. Heckler

    2016-03-01

    Full Text Available The stability of polymer solar cells (PSCs can be influenced by the introduction of particular moieties on the conjugated polymer side chains. In this study, two series of donor-acceptor copolymers, based on bis(thienyldialkoxybenzene donor and benzo[c][1,2,5]thiadiazole (BT or thiazolo[5,4-d]thiazole (TzTz acceptor units, were selected toward effective device scalability by roll-coating. The influence of the partial exchange (5% or 10% of the solubilizing 2-hexyldecyloxy by alternative 2-phenylethoxy groups on efficiency and stability was investigated. With an increasing 2-phenylethoxy ratio, a decrease in solar cell efficiency was observed for the BT-based series, whereas the efficiencies for the devices based on the TzTz polymers remained approximately the same. The photochemical degradation rate for PSCs based on the TzTz polymers decreased with an increasing 2-phenylethoxy ratio. Lifetime studies under constant sun irradiance showed a diminishing initial degradation rate for the BT-based devices upon including the alternative side chains, whereas the (more stable TzTz-based devices degraded at a faster rate from the start of the experiment upon partly exchanging the side chains. No clear trends in the degradation behavior, linked to the copolymer structural changes, could be established at this point, evidencing the complex interplay of events determining PSCs’ lifetime.

  13. Novel bioadhesive polymers as intra-articular agents: Chondroitin sulfate-cysteine conjugates.

    Science.gov (United States)

    Suchaoin, Wongsakorn; Bonengel, Sonja; Griessinger, Julia Anita; Pereira de Sousa, Irene; Hussain, Shah; Huck, Christian W; Bernkop-Schnürch, Andreas

    2016-04-01

    The aim of this study was to generate and characterize a chondroitin sulfate-cysteine conjugate (CS-cys) as a novel bioadhesive agent for intra-articular use. Mucoadhesive properties of synthesized CS-cys were investigated by rheological measurement of polymer-mucus mixture and rotating cylinder method, while bioadhesive features of CS-cys on porcine articular cartilage were evaluated via tensile studies. Thiolation was achieved by attachment of l-cysteine to CS via amide bond formation mediated by carbodiimide as a coupling reagent. The conjugate exhibited 421.17±35.14 μmol free thiol groups per gram polymer. The reduced CS-cys displayed 675.09±39.67 μmol free thiol groups per gram polymer after disulfide bonds reduction using tris(2-carboxyethyl)phosphine hydrochloride. The increase in dynamic viscosity of thiolated CS due to oxidative disulfide bond formation was demonstrated using capillary viscometer. The combination of CS-cys and mucus led to 4.57-fold increase in dynamic viscosity in comparison with mucus control. Furthermore, adhesion time to porcine mucosa of CS-cys-based test disk was enhanced by 2.48-fold compared to unmodified CS as measured by rotating cylinder method suggesting the interaction between thiomers and mucus gel layer via disulfide bonds formation. Tensile studies of thiolated CS on porcine articular cartilage showed 5.37- and 1.76-fold increase in the total work of adhesion and the maximum detachment force, respectively, in comparison with unmodified CS indicating bioadhesive features of CS-cys. Cytotoxicity of CS-cys was assessed in Caco-2 cells and rat primary articular chondrocytes using MTT and LDH release assay, thereby showing the safety of CS-cys at a concentration of 0.25% (w/v) in Caco-2 cells. Furthermore, 0.1% of CS-cys was found non-toxic to rat primary articular chondrocytes. According to these results, CS-cys provides improved bioadhesive properties that might be useful as an intra-articular agent for treatment of

  14. Controlling Film Morphology in Conjugated Polymer

    Science.gov (United States)

    Park, Lee Y.; Munro, Andrea M.; Ginger, David S.

    2009-01-01

    We study the effects of patterned surface chemistry on the microscale and nanoscale morphology of solution-processed donor/acceptor polymer-blend films. Focusing on combinations of interest in polymer solar cells, we demonstrate that patterned surface chemistry can be used to tailor the film morphology of blends of semiconducting polymers such as poly-[2-(3,7-dimethyloctyloxy)-5-methoxy-p-phenylenevinylene] (MDMO-PPV), poly-3-hexylthiophene (P3HT), poly[(9,9-dioctylflorenyl-2,7-diyl)-co-benzothiadiazole)] (F8BT), and poly(9,9-dioctylfluorene-co-bis-N,N’-(4-butylphenyl)-bis-N,N’-phenyl-1,4-phenylendiamine) (PFB) with the fullerene derivative, [6,6]-phenyl-C61-butyric acid methyl ester (PCBM). We present a method for generating patterned, fullerene-terminated monolayers on gold surfaces, and use microcontact printing and Dip-Pen Nanolithography (DPN) to pattern alkanethiols with both micro- and nanoscale features. After patterning with fullerenes and other functional groups, we backfill the rest of the surface with a variety of thiols to prepare substrates with periodic variations in surface chemistry. Spin coating polymer:PCBM films onto these substrates, followed by thermal annealing under nitrogen, leads to the formation of structured polymer films. We characterize these films with Atomic Force Microscopy (AFM), Raman spectroscopy, and fluorescence microscopy. The surface patterns are effective in guiding phase separation in all of the polymer:PCBM systems investigated, and lead to a rich variety of film morphologies that are inaccessible with unpatterned substrates. We demonstrate our ability to guide pattern formation in films thick enough of be of interest for actual device applications (up to 200 nm in thickness) using feature sizes as small as 100 nm. Finally, we show that the surface chemistry can lead to variations in film morphology on length scales significantly smaller than those used in generating the original surface patterns. The variety of

  15. Enzyme-Polymers Conjugated to Quantum-Dots for Sensing Applications

    Directory of Open Access Journals (Sweden)

    Alexandra Mansur

    2011-10-01

    Full Text Available In the present research, the concept of developing a novel system based on polymer-enzyme macromolecules was tested by coupling carboxylic acid functionalized poly(vinyl alcohol (PVA-COOH to glucose oxidase (GOx followed by the bioconjugation with CdS quantum-dots (QD. The resulting organic-inorganic nanohybrids were characterized by UV-visible spectroscopy, infrared spectroscopy, Photoluminescence spectroscopy (PL and transmission electron microscopy (TEM. The spectroscopy results have clearly shown that the polymer-enzyme macromolecules (PVA-COOH/GOx were synthesized by the proposed zero-length linker route. Moreover, they have performed as successful capping agents for the nucleation and constrained growth of CdS quantum-dots via aqueous colloidal chemistry. The TEM images associated with the optical absorption results have indicated the formation of CdS nanocrystals with estimated diameters of about 3.0 nm. The “blue-shift” in the visible absorption spectra and the PL values have provided strong evidence that the fluorescent CdS nanoparticles were produced in the quantum-size confinement regime. Finally, the hybrid system was biochemically assayed by injecting the glucose substrate and detecting the formation of peroxide with the enzyme horseradish peroxidase (HRP. Thus, the polymer-enzyme-QD hybrid has behaved as a nanostructured sensor for glucose detecting.

  16. Naphthalene Diimide Based n-Type Conjugated Polymers as Efficient Cathode Interfacial Materials for Polymer and Perovskite Solar Cells.

    Science.gov (United States)

    Jia, Tao; Sun, Chen; Xu, Rongguo; Chen, Zhiming; Yin, Qingwu; Jin, Yaocheng; Yip, Hin-Lap; Huang, Fei; Cao, Yong

    2017-10-18

    A series of naphthalene diimide (NDI) based n-type conjugated polymers with amino-functionalized side groups and backbones were synthesized and used as cathode interlayers (CILs) in polymer and perovskite solar cells. Because of controllable amine side groups, all the resulting polymers exhibited distinct electronic properties such as oxidation potential of side chains, charge carrier mobilities, self-doping behaviors, and interfacial dipoles. The influences of the chemical variation of amine groups on the cathode interfacial effects were further investigated in both polymer and perovskite solar cells. We found that the decreased electron-donating property and enhanced steric hindrance of amine side groups substantially weaken the capacities of altering the work function of the cathode and trap passivation of the perovskite film, which induced ineffective interfacial modifications and declining device performance. Moreover, with further improvement of the backbone design through the incorporation of a rigid acetylene spacer, the resulting polymers substantially exhibited an enhanced electron-transporting property. Upon use as CILs, high power conversion efficiencies (PCEs) of 10.1% and 15.2% were, respectively, achieved in polymer and perovskite solar cells. Importantly, these newly developed n-type polymers were allowed to be processed over a broad thickness range of CILs in photovoltaic devices, and a prominent PCE of over 8% for polymer solar cells and 13.5% for perovskite solar cells can be achieved with the thick interlayers over 100 nm, which is beneficial for roll-to-roll coating processes. Our findings contribute toward a better understanding of the structure-performance relationship between CIL material design and solar cell performance, and provide important insights and guidelines for the design of high-performance n-type CIL materials for organic and perovskite optoelectronic devices.

  17. Effect of introduction of chondroitin sulfate into polymer-peptide conjugate responding to intracellular signals

    Science.gov (United States)

    Tomiyama, Tetsuro; Toita, Riki; Kang, Jeong-Hun; Koga, Haruka; Shiosaki, Shujiro; Mori, Takeshi; Niidome, Takuro; Katayama, Yoshiki

    2011-09-01

    We recently developed a novel tumor-targeted gene delivery system responding to hyperactivated intracellular signals. Polymeric carrier for gene delivery consists of hydrophilic neutral polymer as main chains and cationic peptide substrate for target enzyme as side chains, and was named polymer-peptide conjugate (PPC). Introduction of chondroitin sulfate (CS), which induces receptor-medicated endocytosis, into polymers mainly with a high cationic charge density such as polyethylenimine can increase tumor-targeted gene delivery. In the present study, we examined whether introduction of CS into PPC containing five cationic amino acids can increase gene expression in tumor cells. Size and zeta potential of plasmid DNA (pDNA)/PPC/CS complex were <200 nm and between -10 and -15 mV, respectively. In tumor cell experiments, pDNA/PPC/CS complex showed lower stability and gene regulation, compared with that of pDNA/PPC. Moreover, no difference in gene expression was identified between positive and negative polymer. These results were caused by fast disintegration of pDNA/PPC/CS complexes in the presence of serum. Thus, we suggest that introduction of negatively charged CS into polymers with a low charge density may lead to low stability and gene regulation of complexes.

  18. Non-covalent functionalization of single wall carbon nanotubes and graphene by a conjugated polymer

    KAUST Repository

    Jiwuer, Jilili

    2014-07-07

    We report first-principles calculations on the binding of poly[(9,9-bis-(6-bromohexylfluorene-2,7-diyl)-co-(benzene-1,4-diyl)] to a (8,0) single wall carbon nanotube (SWCNT) and to graphene. Considering different relative orientations of the subsystems, we find for the generalized gradient approximation a non-binding state, whereas the local density approximation predicts reasonable binding energies. The results coincide after inclusion of van der Waals corrections, which demonstrates a weak interaction between the polymer and SWCNT/graphene, mostly of van der Waals type. Accordingly, the density of states shows essentially no hybridization. The physisorption mechanism explains recent experimental observations and suggests that the conjugated polymer can be used for non-covalent functionalization.

  19. Non-covalent functionalization of single wall carbon nanotubes and graphene by a conjugated polymer

    KAUST Repository

    Jiwuer, Jilili; Abdurahman, Ayjamal; Gü lseren, Oğuz; Schwingenschlö gl, Udo

    2014-01-01

    We report first-principles calculations on the binding of poly[(9,9-bis-(6-bromohexylfluorene-2,7-diyl)-co-(benzene-1,4-diyl)] to a (8,0) single wall carbon nanotube (SWCNT) and to graphene. Considering different relative orientations of the subsystems, we find for the generalized gradient approximation a non-binding state, whereas the local density approximation predicts reasonable binding energies. The results coincide after inclusion of van der Waals corrections, which demonstrates a weak interaction between the polymer and SWCNT/graphene, mostly of van der Waals type. Accordingly, the density of states shows essentially no hybridization. The physisorption mechanism explains recent experimental observations and suggests that the conjugated polymer can be used for non-covalent functionalization.

  20. Solid-phase based synthesis of ureidopyrimidinone-peptide conjugates for supramolecular biomaterials

    NARCIS (Netherlands)

    Feijter, de I.; Goor, O.J.G.M.; Hendrikse, S.I.S.; Comellas Aragones, M.; Sontjens, S.H.M.; Zaccaria, S.; Fransen, P.P.K.H.; Peeters, J.W.; Milroy, L.G.; Dankers, P.Y.W.

    2015-01-01

    Supramolecular polymers have shown to be powerful scaffolds for tissue engineering applications. Supramolecular biomaterials functionalized with ureidopyrimidinone (UPy) moieties, which dimerize via quadruple hydrogen-bond formation, are eminently suitable for this purpose. The conjugation of the

  1. Non-covalent functionalization of carbon nanotubes: Controlling Chirality Selectivity via Alkyl Groups of Conjugated Co-Polymers

    Science.gov (United States)

    Weight, Braden; Gifford, Brendan; Kilina, Svetlana

    Carbon nanotubes (CNTs) play an important role in nanotechnology, including electronics, chemical sensors, and solar cells. Their electronic and optical properties depend on the size and geometry (chirality) of the nanotube. However, one main concern regarding nanotube application in optoelectronic devices is the difficulty of separating them based upon chirality after synthesis, as all known synthesis methods produce more than one chirality simultaneously. To get around this, one method is the functionalization of the CNTs via non-covalent bonding of co-polymers by wrapping them around the tube. We use force field simulations to explore the effects of various structural manipulations to the co-polymer 9,9-dialkylfluorenyl-2,7-diyl bipyridine (PFO-BPY) to find the preferential mechanisms of selective interactions between the PFO-BPY and CNTs of various chiralities. In particular, we focus on the effect of the branching in alkyl side-groups of PFO-BPY on their binding to the CNT surface. We have observed correlations between the side-group structures and their wrapping morphology on the CNT-Polymer interactions. Our calculations demonstrate that the branching in the position closest to the conjugated backboned results in the strongest interaction with all CNT. This research was supported by the National Science Foundation (CHE 1413614) and the Center for Computationally-Assisted Science and Technology at NDSU.

  2. Review of Polymer, Dye-Sensitized, and Hybrid Solar Cells

    Directory of Open Access Journals (Sweden)

    S. N. F. Mohd-Nasir

    2014-01-01

    Full Text Available The combination of inorganic nanoparticles semiconductor, conjugated polymer, and dye-sensitized in a layer of solar cell is now recognized as potential application in developing flexible, large area, and low cost photovoltaic devices. Several conjugated low bandgap polymers, dyes, and underlayer materials based on the previous studies are quoted in this paper, which can provide guidelines in designing low cost photovoltaic solar cells. All of these materials are designed to help harvest more sunlight in a wider range of the solar spectrum besides enhancing the rate of charge transfer in a device structure. This review focuses on developing solid-state dye-synthesized, polymer, and hybrid solar cells.

  3. Bioinspired dopamine-conjugated polyaspartamide as a novel and versatile adhesive material

    Directory of Open Access Journals (Sweden)

    B. Wang

    2017-08-01

    Full Text Available Biomimetic dopamine-conjugated polyaspartamides as novel adhesive materials were synthesized and characterized. These modified polyaspartamides contain three different groups combined with dopamine (DOPA, i.e., γ-amino butyric acid (GABA, ethanolamine (EA and octylamine (OA, which are referred to as PolyAspAm (DOPA/GABA, PolyAspAm(DOPA/EA and PolyAspAm(DOPA/OA, respectively. These three water-swollen polymer glues show good adhesion (0.1~0.4 MPa with various daily-life materials (aluminum foil, glass and paper as well as some plastic substrates (PET and PMMA. Compared to the polymers with more hydrophilic groups (GABA and EA, the polymer glue with the hydrophobic alkyl group (OA exhibited higher adhesive strength values on most substrates. In addition, when applied to biological porcine skin, these glues demonstrated adhesion of values of 15~20 kPa with EA- and OA-conjugated polymers. These results suggest the great potential of dopamine-modified polyaspartamides as versatile and efficient polymeric glues for industrial and biomedical applications.

  4. Diketopyrrolopyrrole-Based Conjugated Polymer Entailing Triethylene Glycols as Side Chains with High Thin-Film Charge Mobility without Post-Treatments

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Si-Fen [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; University of Chinese Academy of Sciences, Beijing 100049 P. R. China; Liu, Zi-Tong [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; Cai, Zheng-Xu [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; Dyson, Matthew J. [Department of Materials and Centre for Plastic Electronics, Imperial College London, London SW72AZ UK; Stingelin, Natalie [Department of Materials and Centre for Plastic Electronics, Imperial College London, London SW72AZ UK; Chen, Wei [Materials Science Division, Argonne National Laboratory, 9700 Cass Avenue Lemont IL 60439 USA; Institute for Molecular Engineering, The University of Chicago, 5640 South Ellis Avenue Chicago IL 60637 USA; Ju, Hua-Jun [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; Zhang, Guan-Xin [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; Zhang, De-Qing [Beijing National Laboratory for Molecular Sciences, CAS Key Laboratory of Organic Solids, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 P. R. China; University of Chinese Academy of Sciences, Beijing 100049 P. R. China

    2017-04-18

    Side chain engineering of conjugated donor-acceptor polymers is a new way to manipulate their optoelectronic properties. Two new diketopyrrolopyrrole (DPP)-terthiophene-based conjugated polymers PDPP3T-1 and PDPP3T-2, with both hydrophilic triethylene glycol (TEG) and hydrophobic alkyl chains, are reported. It is demonstrated that the incorporation of TEG chains has a significant effect on the interchain packing and thin-film morphology with noticeable effect on charge transport. Polymer chains of PDPP3T-1 in which TEG chains are uniformly distributed can self-assemble spontaneously into a more ordered thin film. As a result, the thin film of PDPP3T-1 exhibits high saturated hole mobility up to 2.6 cm(2) V-1 s(-1) without any post-treatment. This is superior to those of PDPP3T with just alkyl chains and PDPP3T-2. Moreover, the respective field effect transistors made of PDPP3T-1 can be utilized for sensing ethanol vapor with high sensitivity (down to 100 ppb) and good selectivity.

  5. Fabrication of multicolor fluorescent polyvinyl alcohol through surface modification with conjugated polymers by oxidative polymerization

    Science.gov (United States)

    Hai, Thien An Phung; Sugimoto, Ryuichi

    2018-06-01

    A simple method for the preparation of multicolor polyvinyl alcohol (PVA) by chemical oxidative polymerization is introduced. The PVA surface was successfully modified with conjugated polymers composed of 3-hexylthiophene (3HT) and fluorene (F). The incorporation of the 3HT/F copolymer onto the PVA surface was confirmed by Fourier-transform infrared (FT-IR), ultraviolet-visible (UV-vis), and fluorescence spectroscopies, X-ray diffraction (XRD), as well as thermogravimetric analysis (TGA), contact angle, and field-emission scanning electron microscopy (FE-SEM) coupled with energy dispersive X-ray (EDX) analysis. Different 3HT/F ratios on the PVA surface result in optical properties that include multicolor-emission and absorption behavior. The color of the resultant (3HT/F)-g-PVA shifted from red to blue, and the quantum yield increased with increasing F content. The surface hydrophobicity of the modified PVA increased significantly through grafting with the conjugated polymers, with the water contact angle increasing by 30° compared to pristine PVA. The PVA XRD peaks were less intense following surface modification. Thermogravimetric analyses reveal that the thermal stability of the PVA decreases as a result of grafting with the 3HT/F copolymers.

  6. Alkylated indacenodithieno[3,2-b]thiophene-based all donor ladder-type conjugated polymers for organic thin film transistors

    KAUST Repository

    Lu, Rimei; Han, Yang; Zhang, Weimin; Zhu, Xiuxiu; Fei, Zhuping; Hodsden, Thomas; Anthopoulos, Thomas D.; Heeney, Martin

    2018-01-01

    We report the synthesis of a series of indacenodithieno[3,2-b]thiophene (IDTT) based conjugated polymers by copolymerization with three different electron rich co-monomers [thiophene (T), thieno[3,2-b]thiophene (TT) and dithieno[3,2-b:2',3'-d

  7. Immunoglobulin and enzyme-conjugated dextran polymers enhance u-PAR staining intensity of carcinoma cells in peripheral blood smears

    DEFF Research Database (Denmark)

    Werther, K; Normark, M; Hansen, B F

    1999-01-01

    phenotyping of disseminated carcinoma cells in bone marrow and peripheral blood smears. In the first step, the cells were incubated with antibodies against urokinase plasminogen activator receptor (u-PAR) and subsequently with secondary antibodies conjugated to peroxidase-labeled dextran polymers. A brown...

  8. Excited State Assignment and Laser Action in π-Conjugated Polymers

    Science.gov (United States)

    Vardeny, Z. V.

    1998-03-01

    We have applied a variety of ps transient and cw spectroscopies to elucidate the ground and excited electronic states of luminescent and nonluminescent thin films and solutions of π-conjugated polymers. These techniques include photoinduced absorption (PA), photoluminescence (PL), resonant Raman scattering (RRS), electro-absorption (EA), two photon absorption (TPA), and PA detected magnetic resonance. We found that the luminescence efficiency, the resonant and subgap third-order nonlinear optical properties and the RRS dispersion in these polymers are determined by the energies and symmetries of a subset of the excited states, including a series of singlet excitons with odd (B_u) and even (A_g) parity lying below a continuum band. Among them, the lowest Bu exciton (1B_u) and two other dominant Ag excitons (mAg and kA_g) are particularly important in determining the EA, TPA, and excitonic ps PA spectra.(S.V. Frolov, M. Liess, P.A. Lane, W. Gellermann, Z.V. Vardeny, M. Ozaki, and K. Yoshino, Phys. Rev. Lett). 78, 4285 (1997). We also found(M. Ozaki, E. Ehrenfreund, R.E. Benner, T.J. Baron, K. Yoshino, and Z.V. Vardeny, Phys. Rev. Lett). 79, 1762 (1997). that the RRS phonon dispersion with the laser excitation energy is governed by the dependence of lowest Ag exciton (2A_g) on the chain length distribution in the polymer. This leads to stronger RRS dispersion in nonluminescent polymers. Moreover the relative energies of the 1Bu and 2Ag excitons determine the PL quantum efficiency η, regardless of the ground state degeneracy. If E(2A_g) < E(1B_u) then η is small because of the dipole forbidden character of the lowest singlet. We will give examples of nonluminescent polymers which belong to this class with both degenerate and nondegenerate ground state, respectively. On the other hand, if E(1B_u) < E(2A_g) then η is large and the polymer might be considered as active material for display applications. Again we give examples of highly luminescent polymers with

  9. A New Property of Conjugated Polymer PFP: Catalytic Degradation of Methylene Blue Aqueous Solution

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    A new property of conjugated polymer poly(furancarbinol-co-phenol)(PFP) was studied.The target copolymer was used as a catalyst after proper heating treatment. And dye methylene blue (MB) could be fully degraded and largely mineralized on PFP, under natural light or even in dark, in a few minutes. Furthermore, the catalytic activity could be preserved after several runs and the catalyst was readily separated. The effect of calcination temperature was also observed.

  10. Driving High-Performance n- and p-type Organic Transistors with Carbon Nanotube/Conjugated Polymer Composite Electrodes Patterned Directly from Solution

    KAUST Repository

    Hellstrom, Sondra L.; Jin, Run Zhi; Stoltenberg, Randall M.; Bao, Zhenan

    2010-01-01

    We report patterned deposition of carbon nanotube/conjugated polymer composites from solution with high nanotube densities and excellent feature resolution. Such composites are suited for use as electrodes in high-performance transistors

  11. BioArtificial polymers

    Science.gov (United States)

    Szałata, Kamila; Gumi, Tania

    2017-07-01

    Nowadays, the polymer science has impact in practically all life areas. Countless benefits coming from the usage of materials with high mechanical and chemical resistance, variety of functionalities and potentiality of modification drive to the development of new application fields. Novel approaches of combining these synthetic substances with biomolecules lead to obtain multifunctional hybrid conjugates which merge the bioactivity of natural component with outstanding properties of artificial polymer. Over the decades, an immense progress in bioartificial composites domain allowed to reach a high level of knowledge in terms of natural-like systems engineering, leading to diverse strategies of biomolecule immobilization. Together with different available options, including covalent and noncovalent attachment, come various challenges, related mainly with maintaining the biological activity of fixed molecules. Even though the amount of applications that achieve commercial status is still not substantial, and is expanding continuously in the disciplines like "smart materials," biosensors, delivery systems, nanoreactors and many others. A huge number of remarkable developments reported in the literature present a potential of bioartificial conjugates as a fabrics with highly controllable structure and multiple functionalities, serving as a powerful nanotechnological tool. This novel approach brings closer biologists, chemists and engineers, who sharing their effort and complementing the knowledge can revolutionize the field of bioartificial polymer science.

  12. Curdlan-conjugated PLGA nanoparticles possess macrophage stimulant activity and drug delivery capabilities

    CSIR Research Space (South Africa)

    Tukulula, M

    2015-02-01

    Full Text Available There is significant interest in the application of nanoparticles to deliver immunostimulatory signals to cells. We hypothesized that curdlan (immune stimulating polymer) could be conjugated to PLGA and nanoparticles from this copolymer would...

  13. Diketopyrrolopyrrole Polymers for Organic Solar Cells.

    Science.gov (United States)

    Li, Weiwei; Hendriks, Koen H; Wienk, Martijn M; Janssen, René A J

    2016-01-19

    Conjugated polymers have been extensively studied for application in organic solar cells. In designing new polymers, particular attention has been given to tuning the absorption spectrum, molecular energy levels, crystallinity, and charge carrier mobility to enhance performance. As a result, the power conversion efficiencies (PCEs) of solar cells based on conjugated polymers as electron donor and fullerene derivatives as electron acceptor have exceeded 10% in single-junction and 11% in multijunction devices. Despite these efforts, it is notoriously difficult to establish thorough structure-property relationships that will be required to further optimize existing high-performance polymers to their intrinsic limits. In this Account, we highlight progress on the development and our understanding of diketopyrrolopyrrole (DPP) based conjugated polymers for polymer solar cells. The DPP moiety is strongly electron withdrawing and its polar nature enhances the tendency of DPP-based polymers to crystallize. As a result, DPP-based conjugated polymers often exhibit an advantageously broad and tunable optical absorption, up to 1000 nm, and high mobilities for holes and electrons, which can result in high photocurrents and good fill factors in solar cells. Here we focus on the structural modifications applied to DPP polymers and rationalize and explain the relationships between chemical structure and organic photovoltaic performance. The DPP polymers can be tuned via their aromatic substituents, their alkyl side chains, and the nature of the π-conjugated segment linking the units along the polymer chain. We show that these building blocks work together in determining the molecular conformation, the optical properties, the charge carrier mobility, and the solubility of the polymer. We identify the latter as a decisive parameter for DPP-based organic solar cells because it regulates the diameter of the semicrystalline DPP polymer fibers that form in the photovoltaic blends with

  14. Well-defined degradable brush polymer-drug conjugates for sustained delivery of Paclitaxel.

    Science.gov (United States)

    Yu, Yun; Chen, Chih-Kuang; Law, Wing-Cheung; Mok, Jorge; Zou, Jiong; Prasad, Paras N; Cheng, Chong

    2013-03-04

    To achieve a conjugated drug delivery system with high drug loading but minimal long-term side effects, a degradable brush polymer-drug conjugate (BPDC) was synthesized through azide-alkyne click reaction of acetylene-functionalized polylactide (PLA) with azide-functionalized paclitaxel (PTXL) and poly(ethylene glycol) (PEG). Well-controlled structures of the resulting BPDC and its precursors were verified by (1)H NMR and gel permeation chromatography (GPC) characterizations. With nearly quantitative click efficiency, drug loading amount of the BPDC reached 23.2 wt %. Both dynamic light scattering (DLS) analysis and transmission electron microscopy (TEM) imaging indicated that the BPDC had a nanoscopic size around 10-30 nm. The significant hydrolytic degradability of the PLA backbone of the BPDC was confirmed by GPC analysis of its incubated solution. Drug release study showed that PTXL moieties can be released through the cleavage of the hydrolyzable conjugation linkage in pH 7.4 at 37 °C, with 50% release in about 22 h. As illustrated by cytotoxicity study, while the polymeric scaffold of the BPDC is nontoxic, the BPDC exhibited higher therapeutic efficacy toward MCF-7 cancer cells than free PTXL at 0.1 and 1 μg/mL. Using Nile red as encapsulated fluorescence probe, cell uptake study showed effective internalization of the BPDC into the cells.

  15. pH-responsive fluorescence chemical sensor constituted by conjugated polymers containing pyridine rings.

    Science.gov (United States)

    Adachi, Naoya; Kaneko, Yuki; Sekiguchi, Kazuki; Sugiyama, Hiroki; Sugeno, Masafumi

    2015-12-01

    Poly(p-pyridinium phenylene ethynylene)s (PPyPE) functionalized with alternating donor-acceptor repeat units were synthesized by a Pd-catalyzed Sonogashira coupling reaction between diethynyl monomer and di-iodopyridine for use as a pH-responsive fluorescence chemical sensor. The synthesized PPyPE, containing pyridine units, was characterized by FT-IR, (1)H and (13)C NMR, UV-visible and fluorescence spectroscopies. We investigated the relationship between changes of optical properties and protonation/deprotonation of PPyPE containing pyridine units in solution. Addition of HCl decreased and red-shifted the fluorescence intensity of the conjugated polymers that contained pyridine rings; fluorescence intensity of the polymers increased upon addition of NaOH solution. The synthesized PPyPE was found to be an effective and reusable chemical sensor for pH sensing. Copyright © 2015 John Wiley & Sons, Ltd.

  16. Siloxane-Terminated Solubilizing Side Chains: Bringing Conjugated Polymer Backbones Closer and Boosting Hole Mobilities in Thin-Film Transistors

    KAUST Repository

    Mei, Jianguo

    2011-12-21

    We introduce a novel siloxane-terminated solubilizing group and demonstrate its effectiveness as a side chain in an isoindigo-based conjugated polymer. An average hole mobility of 2.00 cm 2 V -1 s -1 (with a maximum mobility of 2.48 cm 2 V -1 s -1), was obtained from solution-processed thin-film transistors, one of the highest mobilities reported to date. In contrast, the reference polymer with a branched alkyl side chain gave an average hole mobility of 0.30 cm 2 V -1 s -1 and a maximum mobility of 0.57 cm 2 V -1 s -1. This is largely explained by the polymer packing: our new polymer exhibited a π-π stacking distance of 3.58 Å, while the reference polymer showed a distance of 3.76 Å. © 2011 American Chemical Society.

  17. Thiazoloisoindigo: a Building Block that Merges the Merits of Thienoisoindigo and Diazaisoindigo for Conjugated Polymers.

    Science.gov (United States)

    Wan, Xiaobo; Li, Chenchen; Wang, Xiao; Hio-Ieng, Un; Peng, Jiawei; Lan, Zhenggang; Cai, Mian; Pei, Jian; Wang, Jieyu

    2018-04-24

    Thiazoloisoindigo, a novel structural variation of isoindigo, is for the first time utilized to synthesize conjugated polymers. Polymer based on thiazoloisoindigo merges the advantages of the one based on thienoisoindigo and diazaisoindigo: It not only exhibits a greatly red shifted UV-vis absorption to the near-infrared region due to its strong tendency to form quinoidal structures, similar to that based on thienoisoindigo, but also shows excellent ambipolar mobility (hole 3.93 and electron 1.07 cm2 V-1 s-1, respectively) in organic field-effect transistors (OFETs), superior than that based on diazaisoindigo, showing the strong electron-withdrawing capability of thiazoloisoindigo. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Nature of the Binding Interactions between Conjugated Polymer Chains and Fullerenes in Bulk Heterojunction Organic Solar Cells

    KAUST Repository

    Ravva, Mahesh Kumar

    2016-10-24

    Blends of π-conjugated polymers and fullerene derivatives are ubiquitous as the active layers of organic solar cells. However, a detailed understanding of the weak noncovalent interactions at the molecular level between the polymer chains and fullerenes is still lacking and could help in the design of more efficient photoactive layers. Here, using a combination of long-range corrected density functional theory calculations and molecular dynamic simulations, we report a thorough characterization of the nature of binding between fullerenes (C60 and PC61BM) and poly(benzo[1,2-b:4,5-b′]dithiophene–thieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) chains. We illustrate the variations in binding strength when the fullerenes dock on the electron-rich vs electron-poor units of the polymer as well as the importance of the role played by the polymer and fullerene side chains and the orientations of the PC61BM molecules with respect to the polymer backbones.

  19. Biomedical applications of polymers

    CERN Document Server

    Gebelein, C G

    1991-01-01

    The biomedical applications of polymers span an extremely wide spectrum of uses, including artificial organs, skin and soft tissue replacements, orthopaedic applications, dental applications, and controlled release of medications. No single, short review can possibly cover all these items in detail, and dozens of books andhundreds of reviews exist on biomedical polymers. Only a few relatively recent examples will be cited here;additional reviews are listed under most of the major topics in this book. We will consider each of the majorclassifications of biomedical polymers to some extent, inclu

  20. Synthesis, characterization, mucoadhesion and biocompatibility of thiolated carboxymethyl dextran-cysteine conjugate.

    Science.gov (United States)

    Shahnaz, G; Perera, G; Sakloetsakun, D; Rahmat, D; Bernkop-Schnürch, A

    2010-05-21

    This study was aimed at improving the mucoadhesive properties of carboxymethyl dextran by the covalent attachment of cysteine. Mediated by a carbodiimide, l-cysteine was covalently attached to the polymer. The resulting CMD-cysteine conjugate (CMD-(273) conjugate) displayed 273+/-20 micromol thiol groups per gram of polymer (mean+/-S.D.; n=3). Within 2h the viscosity of an aqueous mucus/CMD-(273) conjugate mixture pH 7.4 increased at 37 degrees C by more than 85% compared to a mucus/carboxymethyl dextran mixture indicating enlarged interactions between the mucus and the thiolated polymer. Due to the immobilization of cysteine, the swelling velocity of the polymer was significantly accelerated (ppolymer disintegrated within 15 min, whereas tablets of the CMD-(273) conjugate remained stable for 160 min (means+/-S.D.; n=3). Results from LDH and MTT assays on Caco-2 cells revealed 4.96+/-0.98% cytotoxicity and 94.1+/-0.9% cell viability for the CMD-(273) conjugate, respectively. Controlled release of model compound from CMD-(273) conjugate tablets was observed over 6h. These findings suggest that CMD-(273) conjugate is a promising novel polymer for drug delivery systems providing improved mucoadhesive and cohesive properties, greater stability and biocompatibility. Copyright 2010 Elsevier B.V. All rights reserved.

  1. Charge carrier mobility, photovoltaic, and electroluminescent properties of anthracene-based conjugated polymers bearing randomly distributed side chains

    Czech Academy of Sciences Publication Activity Database

    Usluer, Ö.; Kästner, C.; Abbas, M.; Ulbricht, C.; Cimrová, Věra; Wild, A.; Birckner, E.; Tekin, N.; Sariciftci, N. S.; Hoppe, H.; Rathgeber, S.; Egbe, D. A. M.

    2012-01-01

    Roč. 50, č. 16 (2012), s. 3425-3436 ISSN 0887-624X R&D Projects: GA MŠk(CZ) 1M06031 Institutional research plan: CEZ:AV0Z40500505 Keywords : conjugated polymers * organic field-effect transistors * organic solar cells Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.543, year: 2012

  2. Diffuse x-ray scattering study of interfacial structure of self-assembled conjugated polymers

    International Nuclear Information System (INIS)

    Wang Jun; Park, Y.J.; Lee, K.-B.; Hong, H.; Davidov, D.

    2002-01-01

    The interfacial structures of self-assembled heterostructures through alternate deposition of conjugated and nonconjugated polymers were studied by x-ray reflectivity and nonspecular scattering. We found that the interfacial width including the effects of both interdiffusion and interfacial roughness (correlated) was mainly contributed by the latter one. The self-assembled deposition induced very small interdiffusion between layers. The lateral correlation length ξ parallel grew as a function of deposition time (or film thickness) described by a power law ξ parallel ∝t β/H and was also observed from the off-specular scattering

  3. Difluorobenzothiadiazole based two-dimensional conjugated polymers with triphenylamine substituted moieties as pendants for bulk heterojunction solar cells

    Directory of Open Access Journals (Sweden)

    W. H. Lee

    2017-11-01

    Full Text Available Three donor/acceptor (D/A-type two-dimensional polythiophenes (PTs; PBTFA13, PBTFA12, PBTFA11 featuring difluorobenzothiadiazole (DFBT derivatives as the conjugated (acceptor units in the polymer backbone and tertbutyl–substituted triphenylamine (tTPA-containing moieties as (donor pendants have been synthesized and characterized. These PTs exhibited good thermal stabilities, broad absorption spectra, and narrow optical band gaps. The cutoff wavelength of the UV–Vis absorption band was red-shifted upon increasing the content of the DFBT units in the PTs. Bulk heterojunction solar cells having an active layer comprising blends of the PTs and fullerene derivatives [6,6] phenyl-C61/71-butyric acid methyl ester (PC61BM/PC71BM were fabricated; their photovoltaic performance was strongly dependent on the content of the DFBT derivative in the PT. Incorporating a suitable content of the DFBT derivative in the polymer backbone enhanced the solar absorption ability and conjugation length of the PTs. The photovoltaic properties of the PBTFA13-based solar cells were superior to those of the PBTFA11- and PBTFA12-based solar cells.

  4. Siloxane-Terminated Solubilizing Side Chains: Bringing Conjugated Polymer Backbones Closer and Boosting Hole Mobilities in Thin-Film Transistors

    KAUST Repository

    Mei, Jianguo; Kim, Do Hwan; Ayzner, Alexander L.; Toney, Michael F.; Bao, Zhenan

    2011-01-01

    We introduce a novel siloxane-terminated solubilizing group and demonstrate its effectiveness as a side chain in an isoindigo-based conjugated polymer. An average hole mobility of 2.00 cm 2 V -1 s -1 (with a maximum mobility of 2.48 cm 2 V -1 s -1

  5. Ampicillin-Ester Bonded Branched Polymers: Characterization, Cyto-, Genotoxicity and Controlled Drug-Release Behaviour

    Directory of Open Access Journals (Sweden)

    Ewa Oledzka

    2014-06-01

    Full Text Available The development and characterization of novel macromolecular conjugates of ampicillin using branched biodegradable polymers has been described in this study. The conjugates have been prepared coupling the β-lactam antibiotic with branched polymer matrices based on the natural oligopeptide core. The cyto- and genotoxicity of the synthesized polymers were evaluated with a bacterial luminescence test, two protozoan assays and Salmonella typhimurium TA1535. The presence of a newly formed covalent bond between the drug and the polymer matrices was confirmed by 1H-NMR and FTIR studies. A drug content (15.6 and 10.2 mole % in the macromolecular conjugates has been determined. The obtained macromolecular products have been subjected to further in vitro release studies. The total percentage of ampicillin released after 21 days of incubation was nearly 60% and 14% and this resulted from the different physicochemical properties of the polymeric matrices. This is the first report on the application of branched biodegradable polymeric matrices for the covalent conjugation of ampicillin. The obtained results showed that the synthesized macromolecular drug-conjugates might slowly release the active drug molecule and improve the pharmacokinetics of ampicillin.

  6. Fullerene-biomolecule conjugates and their biomedicinal applications.

    Science.gov (United States)

    Yang, Xinlin; Ebrahimi, Ali; Li, Jie; Cui, Quanjun

    2014-01-01

    Fullerenes are among the strongest antioxidants and are characterized as "radical sponges." The research on biomedicinal applications of fullerenes has achieved significant progress since the landmark publication by Friedman et al in 1993. Fullerene-biomolecule conjugates have become an important area of research during the past 2 decades. By a thorough literature search, we attempt to update the information about the synthesis of different types of fullerene-biomolecule conjugates, including fullerene-containing amino acids and peptides, oligonucleotides, sugars, and esters. Moreover, we also discuss in this review recently reported data on the biological and pharmaceutical utilities of these compounds and some other fullerene derivatives of biomedical importance. While within the fullerene-biomolecule conjugates, in which fullerene may act as both an antioxidant and a carrier, specific targeting biomolecules conjugated to fullerene will undoubtedly strengthen the delivery of functional fullerenes to sites of clinical interest.

  7. Ultrafast photo-induced nuclear relaxation of a conformationally disordered conjugated polymer probed with transient absorption and femtosecond stimulated Raman spectroscopies

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Wenjian; Donohoo-Vallett, Paul J.; Zhou, Jiawang; Bragg, Arthur E., E-mail: artbragg@jhu.edu [Department of Chemistry, Johns Hopkins University, 3400 N. Charles St., Baltimore, Maryland 21218 (United States)

    2014-07-28

    A combination of transient absorption (TAS) and femtosecond stimulated Raman (FSRS) spectroscopies were used to interrogate the photo-induced nuclear relaxation dynamics of poly(3-cyclohexyl,4-methylthiophene) (PCMT). The large difference in inter-ring dihedral angles of ground and excited-state PCMT make it an ideal candidate for studying large-amplitude vibrational relaxation associated with exciton trapping. Spectral shifting in the S{sub 1} TA spectra on sub-ps timescales (110 ± 20 and 800 ± 100 fs) is similar to spectroscopic signatures of excited-state relaxation observed with related photoexcited conjugated polymers and which have been attributed to exciton localization and a combination of resonant energy transfer and torsional relaxation, respectively. Measurements made with both techniques reveal fast PCMT S{sub 1} decay and triplet formation (τ{sub S1} = 25–32 ps), which is similar to the excited-state dynamics of short oligothiophenes and highly twisted polyconjugated molecules. On ultrafast timescales FSRS of S{sub 1} PCMT offers a new perspective on the nuclear dynamics that underlie localization of excitons in photoexcited conjugated polymers: Spectral dynamics in the C=C stretching region (1400–1600 cm{sup −1}) include a red-shift of the in-phase C=C stretching frequency, as well as a change in the relative intensity of in-phase and out-of-phase stretch intensities on a timescale of ∼100 fs. Both changes indicate an ultrafast vibrational distortion that increases the conjugation length in the region of the localized excitation and are consistent with exciton self-localization or trapping. Wavelength-dependent excited-state FSRS measurements further demonstrate that the C=C stretching frequency provides a useful spectroscopic handle for interrogating the degree of delocalization in excited conjugated polymers given the selectivity achieved via resonance enhancement.

  8. Correlation of Disorder and Charge Transport in a Range of Indacenodithiophene-Based Semiconducting Polymers

    KAUST Repository

    Nikolka, Mark

    2017-12-13

    Over the past 25 years, various design motifs have emerged for the development of organic semiconductors for demanding applications in flexible organic light emitting diode display backplanes or even printed organic logic. Due to their large area uniformity paired with high charge carrier mobilities, conjugated polymers have attracted increasing attention in this respect. However, the performances delivered by current generation conjugated polymers still fall short of many industrial requirements demanding devices with ideal transistor characteristics and higher mobilities. The discovery of conjugated polymers with low energetic disorder, such as the indacenodithiophene-based polymer indacenodithiophene-co-benzothiadiazole, represent an exciting opportunity to breach this chasm if these materials can be further optimized while maintaining their low disorder. Here, it is shown how both the charge transport properties as well as the energetic disorder are affected by tuning the molecular structure of a large range of indacenodithiophene-based semiconducting polymer derivatives. This study allows to understand better the interplay between molecular design and structure of the polymer backbone and the degree of energetic disorder that governs the charge transport properties in thin polymer films.

  9. A salt water battery with high stability and charging rates made from solution processed conjugated polymers with polar side chains

    KAUST Repository

    Moia, Davide; Giovannitti, Alexander; Szumska, Anna A.; Schnurr, Martin; Rezasoltani, Elham; Maria, Iuliana P.; Barnes, Piers R. F.; McCulloch, Iain; Nelson, Jenny

    2017-01-01

    conjugated polymer backbones, allowed the films to maintain constant capacity at high charge and discharge rates (>1000 C-rate). The electrodes also show good stability during electrochemical cycling (less than 30% decrease in capacity over >1000 cycles) and an output voltage up to 1.4 V. The performance of these semiconducting polymers with polar side-chains demonstrates the potential of this material class for fast-charging, water based electrochemical energy storage devices.

  10. Elucidation of the Structure Formation of Polymer-Conjugated Proteins in Solution and Block Copolymer Templates

    Science.gov (United States)

    Ferebee, Rachel L.

    The broader technical objective of this work is to contribute to the development of enzyme-functionalized nanoporous membranes that can function as autonomous and target selective dynamic separators. The scientific objective of the research performed within this thesis is to elucidate the parameters that control the mixing of proteins in organic host materials and in block copolymers templates in particular. A "biomimetic" membrane system that uses enzymes to selectively neutralize targets and trigger a change in permeability of nanopores lined with a pH-responsive polymer has been fabricated and characterized. Mechanical and functional stability, as well as scalability, have been demonstrated for this system. Additional research has focused on the role of polymeric ligands on the solubility characteristics of the model protein, Bovine Serum Albumin (BSA). For this purpose BSA was conjugated with poly(ethylene glycol) (PEG) ligands of varied degree of polymerization and grafting density. Combined static and dynamic light scattering was used (in conjunction with MALDI-TOF) to determine the second virial coefficient in PBS solutions. At a given mass fraction PEG or average number of grafts, the solubility of BSA-PEG conjugates is found to increase with the degree of polymerization of conjugated PEG. This result informs the synthesis of protein-conjugate systems that are optimized for the fabrication of block copolymer blend materials with maximum protein loading. Blends of BSA-PEG conjugates and block copolymer (BCP) matrices were fabricated to evaluate the dispersion morphology and solubility limits in a model system. Electron microscopy was used to evaluate the changes in lamellar spacing with increased filling fraction of BSA-PEG conjugates.

  11. Development of quinoxaline based polymers for photovoltaic applications

    Czech Academy of Sciences Publication Activity Database

    Yuan, J.; Ouyang, J.; Cimrová, Věra; Leclerc, M.; Najari, A.; Zou, Y.

    2017-01-01

    Roč. 5, č. 8 (2017), s. 1858-1879 ISSN 2050-7526 R&D Projects: GA ČR(CZ) GA13-26542S Institutional support: RVO:61389013 Keywords : conjugated polymers * quinoxaline based * photovoltaic s Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 5.256, year: 2016

  12. Programmed Switching of Single Polymer Conformation on DNA Origami

    DEFF Research Database (Denmark)

    Krissanaprasit, Abhichart; Madsen, Mikael; Knudsen, Jakob Bach

    2016-01-01

    -molecule conjugated polymer. The polymer is functionalized with short single-stranded (ss) DNA strands that extend from the backbone of the polymer and serve as handles. The DNA polymer conjugate can be aligned on DNA origami in three well-defined geometries (straight line, left-turned, and right-turned pattern......) by DNA hybridization directed by single-stranded guiding strands and ssDNA tracks extending from the origami surface and polymer handle. We demonstrate switching of a conjugated organic polymer conformation between left- and right-turned conformations of the polymer on DNA origami based on toehold...

  13. Soluble polymer conjugates for drug delivery.

    Science.gov (United States)

    Minko, Tamara

    2005-01-01

    The use of water-soluble polymeric conjugates as drug carriers offers several possible advantages. These advantages include: (1) improved drug pharmacokinetics; (2) decreased toxicity to healthy organs; (3) possible facilitation of accumulation and preferential uptake by targeted cells; (4) programmed profile of drug release. In this review, we will consider the main types of useful polymeric conjugates and their role and effectiveness as carriers in drug delivery systems.: © 2005 Elsevier Ltd . All rights reserved.

  14. Interactions of a zwitterionic thiophene-based conjugated polymer with surfactants

    DEFF Research Database (Denmark)

    Costa, Telma; De Azevedo, Diego; Stewart, Beverly

    2015-01-01

    In this paper we investigate the optical and structural properties of a zwitterionic poly[3-(N-(4-sulfonato-1-butyl)-N,N-diethylammonium)hexyl-2,5-thiophene] (P3SBDEAHT) conjugated polyelectrolyte (CPE) and its interaction in water with surfactants, using absorption, photoluminescence (PL......), electrical conductivity, molecular dynamics simulations (MDS) and small-angle X-ray scattering (SAXS). Different surfactants were studied to evaluate the effect of the head group and chain length on the self-assembly. PL data emphasize the importance of polymer-surfactant electrostatic interactions...... in the formation of complexes. Nevertheless, conductivity and MDS data have shown that nonspecific interactions also play an important role. These seem to be responsible for the spatial position of the surfactant tail in the complex and, eventually, for breaking-up P3SBDEAHT aggregates. SAXS measurements on P3...

  15. Color optimization of conjugated-polymer/InGaN hybrid white light emitting diodes by incomplete energy transfer

    International Nuclear Information System (INIS)

    Chang, Chi-Jung; Lai, Chun-Feng; Madhusudhana Reddy, P.; Chen, Yung-Lin; Chiou, Wei-Yung; Chang, Shinn-Jen

    2015-01-01

    By using the wavelength conversion method, white light emitting diodes (WLEDs) were produced by applying mixtures of polysiloxane and fluorescent polymers on InGaN based light emitting diodes. UV curable organic–inorganic hybrid materials with high refractive index (1.561), compromised optical, thermal and mechanical properties was used as encapsulants. Red light emitting fluorescent FABD polymer (with 9,9-dioctylfluorene (F), anthracene (A) and 2,1,3-benzothiadiazole (B), and 4,7-bis(2-thienyl)-2,1,3-benzothiadiazole (D) repeating units) and green light emitting fluorescent FAB polymer were used as wavelength converters. The encapsulant/fluorescent polymer mixture and InGaN produce the white light by incomplete energy transfer mechanism. WLEDs with high color rendering index (CRI, about 93), and tunable correlated color temperature (CCT) properties can be produced by controlling the composition and chemical structures of encapsulating polymer and fluorescent polymer in hybrid materials, offering cool-white and neutral-white LEDs. - Highlights: • Highly efficient white light-emitting diodes (WLEDs) were produced. • Conjugated-polymer/InGaN hybrid WLEDs by incomplete energy transfer mechanism. • WLEDs with high color-rendering index and tunable correlated color temperature. • Polysiloxane encapsulant with superior optical, mechanical and thermal properties

  16. Polymer and polymer-hybrid nanoparticles from synthesis to biomedical applications

    CERN Document Server

    Rangelov, Stanislav

    2013-01-01

    Polymeric and hybrid nanoparticles have received increased scientific interest in terms of basic research as well as commercial applications, promising a variety of uses for nanostructures in fields including bionanotechnology and medicine. Condensing the relevant research into a comprehensive reference, Polymer and Polymer-Hybrid Nanoparticles: From Synthesis to Biomedical Applications covers an array of topics from synthetic procedures and macromolecular design to possible biomedical applications of nanoparticles and materials based on original and unique polymers. The book presents a well-r

  17. High-Performance All-Polymer Solar Cells Achieved by Fused Perylenediimide-Based Conjugated Polymer Acceptors.

    Science.gov (United States)

    Yin, Yuli; Yang, Jing; Guo, Fengyun; Zhou, Erjun; Zhao, Liancheng; Zhang, Yong

    2018-05-09

    We report three n-type polymeric electron acceptors (PFPDI-TT, PFPDI-T, and PFPDI-Se) based on the fused perylene diimide (FPDI) and thieno[3,2- b]thiophene, thiophene, or selenophene units for all-polymer solar cells (all-PSCs). These FPDI-based polymer acceptors exhibit strong absorption between 350 and 650 nm with wide optical bandgap of 1.86-1.91 eV, showing good absorption compensation with the narrow bandgap polymer donor. The lowest unoccupied molecular orbital (LUMO) energy levels were located at around -4.11 eV, which are comparable with those of the fullerene derivatives and other small molecular electron acceptors. The conventional all-PSCs based on the three polymer acceptors and PTB7-Th as polymer donor gave remarkable power conversion efficiencies (PCEs) of >6%, and the PFPDI-Se-based all-PSC achieved the highest PCE of 6.58% with a short-circuit current density ( J sc ) of 13.96 mA/cm 2 , an open-circuit voltage ( V oc ) of 0.76 V, and a fill factor (FF) of 62.0%. More interestingly, our results indicate that the photovoltaic performances of the FPDI-based polymer acceptors are mainly determined by the FPDI unit with a small effect from the comonomers, which is quite different from the others reported rylenediimide-based polymer acceptors. This intriguing phenomenon is speculated as the huge geometry configuration of the FPDI unit, which minimizes the effect of the comonomer. These results highlight a promising future for the application of the FPDI-based polymer acceptors in the highly efficient all-PSCs.

  18. Identification of excited states in conjugated polymers

    International Nuclear Information System (INIS)

    Hartwell, Lewis John

    2003-01-01

    This thesis reports quasi steady state photoinduced absorption measurements from three conjugated polymers: polypyridine (PPy), polyfluorene (PFO) and the emeraldine base (EB) form of polyaniline. The aim of these experiments was to determine the nature of the photoexcited states existing in these materials in the millisecond time domain, as this has important consequences for the operation of real devices manufactured using these materials. The results from the photoinduced absorption experiments are closely compared with published results from pulse radiolysis experiments. In all cases there is very good correspondence between the two data sets, which has enabled the photoexcited states to be assigned with a high degree of confidence. Quasi steady-state photoinduced absorption involves the measurement of the change in absorption of a material in response to optical excitation with a laser beam. The changes in absorption are small, so a dedicated instrument was developed and optimised for each different sample. Lock-in techniques were used to recover the small signals from the samples. The samples involved were thin films of the polymer spin coated onto sapphire substrates in the cases of PPy and EB. Solution state experiments were conducted on EB. The experiments on PFO were conducted on aligned and unaligned thin films provided by Sony. In the case of the aligned PFO samples, the photoinduced absorption spectrometer was modified to enable polarisation-sensitive data collection. In PPy, both triplet excitons and polarons have been shown to be long-lived photoexcitations, with photoinduced absorption features at 2.29 eV (triplet exciton transition), 1.5 eV and 0.8 eV (polaron transitions). In PFO, the one observed photoinduced band at 1.52 eV is assigned to a triplet exciton. Two photoinduced absorption bands are observed in EB, at 1.4 eV and 0.8 eV. These are assigned to a self-trapped CT singlet exciton and triplet exciton, respectively. (author)

  19. Polymer Brushes: Synthesis, Characterization, Applications

    Science.gov (United States)

    Advincula, Rigoberto C.; Brittain, William J.; Caster, Kenneth C.; Rühe, Jürgen

    2004-09-01

    Materials scientists, polymer chemists, surface physicists and materials engineers will find this book a complete and detailed treatise on the field of polymer brushes, their synthesis, characterization and manifold applications. In a first section, the various synthetic pathways and different surface materials are introduced and explained, followed by a second section covering important aspects of characterization and analysis in both flat surfaces and particles. These specific surface initiated polymerization (SIP) systems such as linear polymers, homopolymers, block copolymers, and hyperbranched polymers are unique compared to previously reported systems by chemisorption or physisorption. They have found their way in both large-scale and miniature applications of polymer brushes, which is covered in the last section. Such 'hairy' surfaces offer fascinating opportunities for addressing numerous problems of both academic and, in particular, industrial interest: high-quality, functional or protective coatings, composite materials, surface engineered particles, metal-organic interfaces, biological applications, micro-patterning, colloids, nanoparticles, functional devices, and many more. It is the desire of the authors that this book will be of benefit to readers who want to "brush-up on polymers".

  20. Hybrid active layers from a conjugated polymer and inorganic nanoparticles for organic light emitting devices with emission colour tuned by electric field

    Energy Technology Data Exchange (ETDEWEB)

    Aleshin, Andrey N; Alexandrova, Elena L; Shcherbakov, Igor P [Ioffe Physical-Technical Institute of the Russian Academy of Sciences, 26, Polytechnicheskaya Str., St Petersburg 194021 (Russian Federation)], E-mail: aleshin@transport.ioffe.ru

    2009-05-21

    We report on the investigation of the electrical and optical properties of hybrid active layers for organic devices consisting of a conjugated polymer MEH-PPV mixed with ZnO and Si nanoparticles. The effect of an electric field on the photoluminescence (PL) from a MEH-PPV : ZnO composite film is studied. We have found that in the absence of an electric field PL emission from the MEH-PPV : ZnO composites have two main maxima in the blue-red regions. Three additional minor PL maxima attributed to the exciplex states were found at {approx}420-480 nm. Application of a voltage bias to planar electrodes significantly suppresses the blue emission. Generation of excited states in the MEH-PPV : ZnO structures implies the presence of several radiative recombination mechanisms with the formation of polymer-nanoparticle complexes including exciplex states and charge transfer between the polymer and nanoparticles that can be controlled by an electric field. This effect provides the possibility to tune by an electric field the emission colour of organic light emitting diodes by combining an efficient emission from both organic/inorganic materials involved.

  1. Hybrid active layers from a conjugated polymer and inorganic nanoparticles for organic light emitting devices with emission colour tuned by electric field

    International Nuclear Information System (INIS)

    Aleshin, Andrey N; Alexandrova, Elena L; Shcherbakov, Igor P

    2009-01-01

    We report on the investigation of the electrical and optical properties of hybrid active layers for organic devices consisting of a conjugated polymer MEH-PPV mixed with ZnO and Si nanoparticles. The effect of an electric field on the photoluminescence (PL) from a MEH-PPV : ZnO composite film is studied. We have found that in the absence of an electric field PL emission from the MEH-PPV : ZnO composites have two main maxima in the blue-red regions. Three additional minor PL maxima attributed to the exciplex states were found at ∼420-480 nm. Application of a voltage bias to planar electrodes significantly suppresses the blue emission. Generation of excited states in the MEH-PPV : ZnO structures implies the presence of several radiative recombination mechanisms with the formation of polymer-nanoparticle complexes including exciplex states and charge transfer between the polymer and nanoparticles that can be controlled by an electric field. This effect provides the possibility to tune by an electric field the emission colour of organic light emitting diodes by combining an efficient emission from both organic/inorganic materials involved.

  2. CONJUGATED BLOCK-COPOLYMERS FOR ELECTROLUMINESCENT DIODES

    NARCIS (Netherlands)

    Hilberer, A; Gill, R.E; Herrema, J.K; Malliaras, G.G; Wildeman, J.; Hadziioannou, G

    In this article we review results obtained in our laboratory on the design and study of new light-emitting polymers. We are interested in the synthesis and characterisation of block copolymers with regularly alternating conjugated and non conjugated sequences. The blocks giving rise to luminescence

  3. A salt water battery with high stability and charging rates made from solution processed conjugated polymers with polar side chains

    KAUST Repository

    Moia, Davide

    2017-11-28

    We report a neutral salt water based battery which uses p-type and n-type solution processed polymer films as the cathode and the anode of the cell. The specific capacity of the electrodes (approximately 30 mAh cm-3) is achieved via formation of bipolarons in both the p-type and n-type polymers. By engineering ethylene glycol and zwitterion based side chains attached to the polymer backbone we facilitate rapid ion transport through the non-porous polymer films. This, combined with efficient transport of electronic charge via the conjugated polymer backbones, allowed the films to maintain constant capacity at high charge and discharge rates (>1000 C-rate). The electrodes also show good stability during electrochemical cycling (less than 30% decrease in capacity over >1000 cycles) and an output voltage up to 1.4 V. The performance of these semiconducting polymers with polar side-chains demonstrates the potential of this material class for fast-charging, water based electrochemical energy storage devices.

  4. Roll-to-Roll printed large-area all-polymer solar cells with 5% efficiency based on a low crystallinity conjugated polymer blend

    Science.gov (United States)

    Gu, Xiaodan; Zhou, Yan; Gu, Kevin; Kurosawa, Tadanori; Yan, Hongping; Wang, Cheng; Toney, Micheal; Bao, Zhenan

    The challenge of continuous printing in high efficiency large-area organic solar cells is a key limiting factor for their widespread adoption. We present a materials design concept for achieving large-area, solution coated all-polymer bulk heterojunction (BHJ) solar cells with stable phase separation morphology between the donor and acceptor. The key concept lies in inhibiting strong crystallization of donor and acceptor polymers, thus forming intermixed, low crystallinity and mostly amorphous blends. Based on experiments using donors and acceptors with different degree of crystallinity, our results showed that microphase separated donor and acceptor domain sizes are inversely proportional to the crystallinity of the conjugated polymers. This methodology of using low crystallinity donors and acceptors has the added benefit of forming a consistent and robust morphology that is insensitive to different processing conditions, allowing one to easily scale up the printing process from a small scale solution shearing coater to a large-scale continuous roll-to-roll (R2R) printer. We were able to continuously roll-to-roll slot die print large area all-polymer solar cells with power conversion efficiencies of 5%, with combined cell area up to 10 cm2. This is among the highest efficiencies realized with R2R coated active layer organic materials on flexible substrate. DOE BRIDGE sunshot program. Office of Naval Research.

  5. Donor and Acceptor Polymers for Bulk Hetero Junction Solar Cell and Photodetector Applications

    KAUST Repository

    Cruciani, Federico

    2018-04-01

    Bulk heterojunction (BHJ) devices represent a very versatile family of organic cells for both the fields of solar energy conversion and photodetection. Organic photovoltaics (OPV) are an attractive alternative to their silicon-based counterparts because of their potential for low-cost roll-to-roll printing, and their intended application in light-weight mechanically conformable devices and in window-type semi-transparent PV modules. Of all proposed OPV candidates, polymer donor with different absorption range are especially promising when used in conjunction with complementary absorbing acceptor materials, like fullerene derivatives (PCBM), conjugated molecules or polymers, achieving nowadays power conversion efficiencies (PCEs) in the range of 10-13% and being a step closer to practical applications. Among the photodetectors (PD), low band gap polymer blended with PCBM decked out the attention, given their extraordinary range of detection from UV to IR and high detectivity values reached so far, compared to the inorganic devices. Since the research has been focused on the enhancement of those numbers for an effective commercialization of organic cells, the topic of the following thesis has been centered on the synthesis of different polymer structures with diverse absorption ranges, used as donor or acceptor, with emphasis on performance in various BHJ devices either for solar cells and photodetectors. In the first part, two new wide band gap polymers, used as donor material in BHJ devices blended with fullerene and small molecule acceptors, are presented. The PBDT_2FT and PBDTT_2FT have shown nice efficiencies from 7% to 9.8%. The device results are implemented with a morphology study and a specific application in a semi-transparent tandem device, reaching a record PCE of 5.4% for average level of transparency of 48%. In another section two new low band gap polymers (Eopt~ 1.26 eV) named DTP_2FBT and (Eopt~ 1.1 eV) named BDTT_BTQ are presented. While the DTP

  6. Compositions, methods, and systems comprising fluorous-soluble polymers

    Science.gov (United States)

    Swager, Timothy M.; Lim, Jeewoo; Takeda, Yohei

    2015-10-13

    The present invention generally relates to compositions, methods, and systems comprising polymers that are fluorous-soluble and/or organize at interfaces between a fluorous phase and a non-fluorous phase. In some embodiments, emulsions or films are provided comprising a polymer. The polymers, emulsions, and films can be used in many applications, including for determining, treating, and/or imaging a condition and/or disease in a subject. The polymer may also be incorporated into various optoelectronic device such as photovoltaic cells, organic light-emitting diodes, organic field effect transistors, or the like. In some embodiments, the polymers comprise pi-conjugated backbones, and in some cases, are highly emissive.

  7. Charge transport in conjugated polymer-semiconductor nanoparticle composite near the percolation threshold

    Science.gov (United States)

    Cardoso, L. S.; Gonçalves, G. E.; Kanda, D. H. F.; Bianchi, R. F.; Nagashima, H. N.

    2017-12-01

    This paper describes a new statistical model to predict the frequency dependence of the conductivity of conjugated polymer-semiconductor nanoparticle composites. The model considers AC conduction in an inhomogeneous medium represented by a two-dimensional model of resistor network. The conductivity between two neighboring sites in the polymer matrix and the semiconductor particles is assumed to obey the random free energy barrier model and the Drude model, respectively. The real and imaginary parts of the AC conductivity were determined using the transfer-matrix technique, and the statistical model was applied to experimental data of thin films composed of polyaniline (PANI) and indium-tin-oxide (ITO) nanoparticles. The conductivity critical exponent ( s) obtained in two dimensions for PANI/ITO films below the percolation threshold was found to be 2.7, which is greater than the universal value of s described by the classical percolation theory ( s = 1.3). This non-universality is explained by the existence of a local electric field distribution in the bulk of the nanocomposite. Finally, these results are discussed in terms of the distribution of potential barriers that vary according to the concentration of ITO amount in the composite.

  8. Fullerene–biomolecule conjugates and their biomedicinal applications

    Directory of Open Access Journals (Sweden)

    Yang X

    2013-12-01

    Full Text Available Xinlin Yang,1 Ali Ebrahimi,1 Jie Li,1,2 Quanjun Cui11Orthopaedic Research Laboratory, Department of Orthopaedic Surgery, University of Virginia School of Medicine, Charlottesville, VA, USA; 2School of Materials Science, Beijing Institute of Technology, Beijing, People's Republic of ChinaAbstract: Fullerenes are among the strongest antioxidants and are characterized as "radical sponges." The research on biomedicinal applications of fullerenes has achieved significant progress since the landmark publication by Friedman et al in 1993. Fullerene–biomolecule conjugates have become an important area of research during the past 2 decades. By a thorough literature search, we attempt to update the information about the synthesis of different types of fullerene–biomolecule conjugates, including fullerene-containing amino acids and peptides, oligonucleotides, sugars, and esters. Moreover, we also discuss in this review recently reported data on the biological and pharmaceutical utilities of these compounds and some other fullerene derivatives of biomedical importance. While within the fullerene–biomolecule conjugates, in which fullerene may act as both an antioxidant and a carrier, specific targeting biomolecules conjugated to fullerene will undoubtedly strengthen the delivery of functional fullerenes to sites of clinical interest.Keywords: fullerene, amino acid, peptide, oligonucleotide, sugar, ester

  9. Application of the conjugate-gradient method to ground-water models

    Science.gov (United States)

    Manteuffel, T.A.; Grove, D.B.; Konikow, Leonard F.

    1984-01-01

    The conjugate-gradient method can solve efficiently and accurately finite-difference approximations to the ground-water flow equation. An aquifer-simulation model using the conjugate-gradient method was applied to a problem of ground-water flow in an alluvial aquifer at the Rocky Mountain Arsenal, Denver, Colorado. For this application, the accuracy and efficiency of the conjugate-gradient method compared favorably with other available methods for steady-state flow. However, its efficiency relative to other available methods depends on the nature of the specific problem. The main advantage of the conjugate-gradient method is that it does not require the use of iteration parameters, thereby eliminating this partly subjective procedure. (USGS)

  10. Characterization of electrosynthesized conjugated polymer-carbon nanotube composite: optical nonlinearity and electrical property.

    Science.gov (United States)

    Bahrami, Afarin; Talib, Zainal Abidin; Shahriari, Esmaeil; Yunus, Wan Mahmood Mat; Kasim, Anuar; Behzad, Kasra

    2012-01-01

    The effects of multi-walled carbon nanotube (MWNT) concentration on the structural, optical and electrical properties of conjugated polymer-carbon nanotube composite are discussed. Multi-walled carbon nanotube-polypyrrole nanocomposites were synthesized by electrochemical polymerization of monomers in the presence of different amounts of MWNTs using sodium dodecylbenzensulfonate (SDBS) as surfactant at room temperature and normal pressure. Field emission scanning electron microscopy (FESEM) indicates that the polymer is wrapped around the nanotubes. Measurement of the nonlinear refractive indices (n(2)) and the nonlinear absorption (β) of the samples with different MWNT concentrations measurements were performed by a single Z-scan method using continuous wave (CW) laser beam excitation wavelength of λ = 532 nm. The results show that both nonlinear optical parameters increased with increasing the concentration of MWNTs. The third order nonlinear susceptibilities were also calculated and found to follow the same trend as n(2) and β. In addition, the conductivity of the composite film was found to increase rapidly with the increase in the MWNT concentration.

  11. Indolo-naphthyridine-6,13-dione Thiophene Building Block for Conjugated Polymer Electronics: Molecular Origin of Ultrahigh n-Type Mobility

    KAUST Repository

    Fallon, Kealan J.

    2016-10-18

    Herein, we present the synthesis and characterization of four conjugated polymers containing a novel chromophore for organic electronics based on an indigoid structure. These polymers exhibit extremely small band gaps of ∼1.2 eV, impressive crystallinity, and extremely high n-type mobility exceeding 3 cm V s. The n-type charge carrier mobility can be correlated with the remarkably high crystallinity along the polymer backbone having a correlation length in excess of 20 nm. Theoretical analysis reveals that the novel polymers have highly rigid nonplanar geometries demonstrating that backbone planarity is not a prerequisite for either narrow band gap materials or ultrahigh mobilities. Furthermore, the variation in backbone crystallinity is dependent on the choice of comonomer. OPV device efficiencies up to 4.1% and charge photogeneration up to 1000 nm are demonstrated, highlighting the potential of this novel chromophore class in high-performance organic electronics.

  12. Indolo-naphthyridine-6,13-dione Thiophene Building Block for Conjugated Polymer Electronics: Molecular Origin of Ultrahigh n-Type Mobility

    KAUST Repository

    Fallon, Kealan J.; Wijeyasinghe, Nilushi; Manley, Eric F.; Dimitrov, Stoichko D.; Yousaf, Syeda A.; Ashraf, Raja S.; Duffy, Warren; Guilbert, Anne A. Y.; Freeman, David M. E.; Al-Hashimi, Mohammed; Nelson, Jenny; Durrant, James R.; Chen, Lin X.; McCulloch, Iain; Marks, Tobin J.; Clarke, Tracey M.; Anthopoulos, Thomas D.; Bronstein, Hugo

    2016-01-01

    Herein, we present the synthesis and characterization of four conjugated polymers containing a novel chromophore for organic electronics based on an indigoid structure. These polymers exhibit extremely small band gaps of ∼1.2 eV, impressive crystallinity, and extremely high n-type mobility exceeding 3 cm V s. The n-type charge carrier mobility can be correlated with the remarkably high crystallinity along the polymer backbone having a correlation length in excess of 20 nm. Theoretical analysis reveals that the novel polymers have highly rigid nonplanar geometries demonstrating that backbone planarity is not a prerequisite for either narrow band gap materials or ultrahigh mobilities. Furthermore, the variation in backbone crystallinity is dependent on the choice of comonomer. OPV device efficiencies up to 4.1% and charge photogeneration up to 1000 nm are demonstrated, highlighting the potential of this novel chromophore class in high-performance organic electronics.

  13. Thermoresponsive Polymers for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Theoni K. Georgiou

    2011-08-01

    Full Text Available Thermoresponsive polymers are a class of “smart” materials that have the ability to respond to a change in temperature; a property that makes them useful materials in a wide range of applications and consequently attracts much scientific interest. This review focuses mainly on the studies published over the last 10 years on the synthesis and use of thermoresponsive polymers for biomedical applications including drug delivery, tissue engineering and gene delivery. A summary of the main applications is given following the different studies on thermoresponsive polymers which are categorized based on their 3-dimensional structure; hydrogels, interpenetrating networks, micelles, crosslinked micelles, polymersomes, films and particles.

  14. Alternative Thieno[3,2-b][1]benzothiophene Isoindigo Polymers for Solar Cell Applications

    KAUST Repository

    Neophytou, Marios; Bryant, Daniel; Lopatin, Sergei; Chen, Hu; Hallani, Rawad K.; Cater, Lewis; McCulloch, Iain; Yue, Wan

    2018-01-01

    This work reports the synthesis, characterization, photophysical, and photovoltaic properties of five new thieno[3,2-b][1]benzothiophene isoindigo (TBTI)-containing low bandgap donor-acceptor conjugated polymers with a series of comonomers

  15. Small-bandgap semiconducting polymers with high near-infrared photoresponse

    NARCIS (Netherlands)

    Hendriks, K.H.; Li, W.; Wienk, M.M.; Janssen, R.A.J.

    2014-01-01

    Lowering the optical bandgap of conjugated polymers while maintaining a high efficiency for photoinduced charge transfer to suitable electron acceptors such as fullerene has remained a formidable challenge in the area of organic photovoltaics. Here we present the synthesis and application of a

  16. Preparation, Single-Molecule Manipulation, and Energy Transfer Investigation of a Polyfluorene-graft-DNA polymer.

    Science.gov (United States)

    Madsen, Mikael; Christensen, Rasmus S; Krissanaprasit, Abhichart; Bakke, Mette R; Riber, Camilla F; Nielsen, Karina S; Zelikin, Alexander N; Gothelf, Kurt V

    2017-08-04

    Conjugated polymers have been intensively studied due to their unique optical and electronic properties combined with their physical flexibility and scalable bottom up synthesis. Although the bulk qualities of conjugated polymers have been extensively utilized in research and industry, the ability to handle and manipulate conjugated polymers at the nanoscale lacks significantly behind. Here, the toolbox for controlled manipulation of conjugated polymers was expanded through the synthesis of a polyfluorene-DNA graft-type polymer (poly(F-DNA)). The polymer possesses the characteristics associated with the conjugated polyfluorene backbone, but the protruding single-stranded DNA provides the material with an exceptional addressability. This study demonstrates controlled single-molecule patterning of poly(F-DNA), as well as energy transfer between two different polymer-DNA conjugates. Finally, highly efficient DNA-directed quenching of polyfluorene fluorescence was shown. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Bright conjugated polymer nanoparticles containing a biodegradable shell produced at high yields and with tuneable optical properties by a scalable microfluidic device.

    Science.gov (United States)

    Abelha, T F; Phillips, T W; Bannock, J H; Nightingale, A M; Dreiss, C A; Kemal, E; Urbano, L; deMello, J C; Green, M; Dailey, L A

    2017-02-02

    This study compares the performance of a microfluidic technique and a conventional bulk method to manufacture conjugated polymer nanoparticles (CPNs) embedded within a biodegradable poly(ethylene glycol) methyl ether-block-poly(lactide-co-glycolide) (PEG 5K -PLGA 55K ) matrix. The influence of PEG 5K -PLGA 55K and conjugated polymers cyano-substituted poly(p-phenylene vinylene) (CN-PPV) and poly(9,9-dioctylfluorene-2,1,3-benzothiadiazole) (F8BT) on the physicochemical properties of the CPNs was also evaluated. Both techniques enabled CPN production with high end product yields (∼70-95%). However, while the bulk technique (solvent displacement) under optimal conditions generated small nanoparticles (∼70-100 nm) with similar optical properties (quantum yields ∼35%), the microfluidic approach produced larger CPNs (140-260 nm) with significantly superior quantum yields (49-55%) and tailored emission spectra. CPNs containing CN-PPV showed smaller size distributions and tuneable emission spectra compared to F8BT systems prepared under the same conditions. The presence of PEG 5K -PLGA 55K did not affect the size or optical properties of the CPNs and provided a neutral net electric charge as is often required for biomedical applications. The microfluidics flow-based device was successfully used for the continuous preparation of CPNs over a 24 hour period. On the basis of the results presented here, it can be concluded that the microfluidic device used in this study can be used to optimize the production of bright CPNs with tailored properties with good reproducibility.

  18. Interpenetrating networks of two conducting polymers

    DEFF Research Database (Denmark)

    Winther-Jensen, Bjørn; West, Keld

    2005-01-01

    Interpenetrating networks (IPNs) of two conjugated polymers are prepared by a combination of a chemical oxidation step and a vapour phase polymerisation step on non-conducting surfaces. In this work ferric tosylate was used as the oxidant as it gives very smooth and homogeneous coatings, and beca......Interpenetrating networks (IPNs) of two conjugated polymers are prepared by a combination of a chemical oxidation step and a vapour phase polymerisation step on non-conducting surfaces. In this work ferric tosylate was used as the oxidant as it gives very smooth and homogeneous coatings......, and because its reaction products can be removed efficiently after the formation of the composite. Several combinations of polymers are demonstrated, and the versatility of the proposed method allows extensions to a wide range of conjugated polymers. The IPNs show optical and electrochemical characteristics......, which are sums of the characteristics from the participating conducting polymers....

  19. HYDROGELS BASED ON POLYMERS OF DEXTRAN TYRAMINE AND TYRAMINE CONJUGATES OF NATURAL POLYMERS

    NARCIS (Netherlands)

    Feijen, Jan; Karperien, Marcel; Jin, R.; Moreira Teixeira, Liliana; Dijkstra, Pieter J.

    2012-01-01

    The invention relates to composition comprising a dextran-tyramine conjugate and a conjugate selected from the group consisting of chondroitin sulphate-tyramine, collagen-tyramine, chitosan-tyramine, chitosan-phloretic acid, gelatine-tyramine, heparan sulphate-tyramine, keratin sulphate-tyramine,

  20. HYDROGELS BASED ON POLYMERS OF DEXTRAN TYRAMINE AND TYRAMINE CONJUGATES OF NATURAL POLYMERS

    NARCIS (Netherlands)

    Karperien, H.B.J.; Jin, R.; Moreira Teixeira, Liliana; Feijen, Jan; Dijkstra, Pieter J.

    2011-01-01

    The invention relates to composition comprising a dextran-tyramine conjugate and a conjugate selected from the group consisting of chondroitin sulphate-tyramine, collagen-tyramine, chitosan-tyramine, chitosan-phloretic acid, gelatine-tyramine, heparan sulphate-tyramine, keratin sulphate tyramine,

  1. Synthesis and Properties of 1,8-Carbazole-Based Conjugated Copolymers

    Directory of Open Access Journals (Sweden)

    Tsuyoshi Michinobu

    2010-07-01

    Full Text Available A new series of conjugated carbazole polymers based on the 1,8-carbazolylene unit was synthesized by the Pd-catalyzed polycondensation between the 1,8-diiodocarbazole derivative and various bifunctional counter comonomers. An alkyne spacer was found to be a key to increasing the molecular weight of the resulting polymers. All the obtained polymers showed good solubilities in the common organic solvents, and they were fully characterized by Gel permeation chromatography (GPC, and 1H NMR and infrared (IR spectroscopies. The UV-vis absorption and fluorescence spectra revealed the relationship between the chemical structure and effective conjugation length. The efficiency order of the carbazole connectivity was 2,7-carbazolylene > 1,8-carbazolylene > 3,6-carbazolylene. The electrochemical properties of these polymers suggested the relatively facile oxidation at ca. +0.5–0.7 V vs. Fc/Fc+ or a high potential as p-type semiconductors. The combination of the electrochemical oxidation potentials and the optical band gaps allowed us to estimate the HOMO and LUMO levels of the polymers. It was shown that the energy levels of the 1,8-carbazole-based conjugated polymers can be tunable by selecting the appropriate comonomer structures.

  2. Highly efficient inverted polymer solar cells based on a cross-linkable water-/alcohol-soluble conjugated polymer interlayer.

    Science.gov (United States)

    Zhang, Kai; Zhong, Chengmei; Liu, Shengjian; Mu, Cheng; Li, Zhengke; Yan, He; Huang, Fei; Cao, Yong

    2014-07-09

    A cross-linkable water/alcohol soluble conjugated polymer (WSCP) material poly[9,9-bis(6'-(N,N-diethylamino)propyl)-fluorene-alt-9,9-bis(3-ethyl(oxetane-3-ethyloxy)-hexyl) fluorene] (PFN-OX) was designed. The cross-linkable nature of PFN-OX is good for fabricating inverted polymer solar cells (PSCs) with well-defined interface and investigating the detailed working mechanism of high-efficiency inverted PSCs based on poly[4,8-bis(2-ethylhexyloxyl)benzo[1,2-b:4,5-b']dithio-phene-2,6-diyl-alt-ethylhexyl-3-fluorothithieno[3,4-b]thiophene-2-carboxylate-4,6-diyl] (PTB7) and (6,6)-phenyl-C71-butyric acid methyl ester (PC71BM) blend active layer. The detailed working mechanism of WSCP materials in high-efficiency PSCs were studied and can be summarized into the following three effects: a) PFN-OX tunes cathode work function to enhance open-circuit voltage (Voc); b) PFN-OX dopes PC71BM at interface to facilitate electron extraction; and c) PFN-OX extracts electrons and blocks holes to enhance fill factor (FF). On the basis of this understanding, the hole-blocking function of the PFN-OX interlayer was further improved with addition of a ZnO layer between ITO and PFN-OX, which led to inverted PSCs with a power conversion efficiency of 9.28% and fill factor high up to 74.4%.

  3. Nanopatterned polymer brushes: conformation, fabrication and applications

    Science.gov (United States)

    Yu, Qian; Ista, Linnea K.; Gu, Renpeng; Zauscher, Stefan; López, Gabriel P.

    2015-12-01

    Surfaces with end-grafted, nanopatterned polymer brushes that exhibit well-defined feature dimensions and controlled chemical and physical properties provide versatile platforms not only for investigation of nanoscale phenomena at biointerfaces, but also for the development of advanced devices relevant to biotechnology and electronics applications. In this review, we first give a brief introduction of scaling behavior of nanopatterned polymer brushes and then summarize recent progress in fabrication and application of nanopatterned polymer brushes. Specifically, we highlight applications of nanopatterned stimuli-responsive polymer brushes in the areas of biomedicine and biotechnology.

  4. Synthesis of conjugated polymers with complex architecture for photovoltaic applications

    DEFF Research Database (Denmark)

    Kiriy, Anton; Krebs, Frederik C

    2017-01-01

    A common approach to bulk heterojunction solar cells involves a “trialand- error” approach in finding optimal kinetically unstable morphologies. An alternative approach assumes the utilization of complex polymer architectures, such as donor–acceptor block copolymers. Because of a covalent preorga...... preorganization of the donor and acceptor components, these materials may form desirable morphologies at thermodynamic equilibrium. This chapter reviews synthetic approaches to such architectures and shows the first photovoltaic results....

  5. The Role of Morphology and Electronic Chain Aggregation on the Optical Gain Properties of Semiconducting Conjugated Polymers

    Science.gov (United States)

    Lampert, Zachary Evan

    Conjugated polymers (CPs) are a novel class of materials that exhibit the optical and electrical properties of semiconductors while still retaining the durability and processability of plastics. CPs are also intrinsically 4-level systems with high luminescence quantum efficiencies making them particularly attractive as organic gain media for solid-state laser applications. However, before CPs can emerge as a commercially available laser technology, a more comprehensive understanding of the morphological dependence of the photophysics is required. In this thesis, the morphology and chain conformation dependence of amplified spontaneous emission (ASE) and optical gain in thin films of poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV) was investigated. By changing the chemical nature of the solvent from which films were cast, as well as the temperature at which films were annealed, CP films with different morphologies, and hence different degrees of interchain interactions were achieved. Contrary to the common perception that polymer morphology plays a decisive role in determining the ASE behavior of thin CP films, we found that chromophore aggregation and degree of conformational order have minimal impact on optical gain. In fact, experimental results indicated that an extremely large fraction of interchain aggregate species and/or exciton dissociating defects are required to significantly alter the optical properties and suppress stimulated emission. These results are pertinent to the fabrication and optimization of an electrically pumped laser device, as improvements in charge carrier mobility through controlled increases in chain aggregation may provide a viable means of optimizing injection efficiency without significantly degrading optical gain. To offset charge-induced absorption losses under electrical pumping, and to enable the use of more compact and economical sources under optical pumping, conjugated polymers exhibiting low lasing

  6. Comparison of the Photovoltaic Characteristics and Nanostructure of Fullerenes Blended with Conjugated Polymers with Siloxane-Terminated and Branched Aliphatic Side Chains

    KAUST Repository

    Kim, Do Hwan

    2013-02-12

    All-organic bulk heterojunction solar cells based on blends of conjugated polymers with fullerenes have recently surpassed the 8% efficiency mark and are well on their way to the industrially relevant ∼15% threshold. Using a low band-gap conjugated polymer, we have recently shown that polymer side chain engineering can lead to dramatic improvement in the in-plane charge carrier mobility. In this article, we investigate the effectiveness of siloxy side chain derivatization in controlling the photovoltaic performance of polymer:[6,6]-phenyl-C[71]-butyric acid methyl ester (PC71BM) blends and hence its influence on charge transport in the out-of-plane direction relevant for organic solar cells. We find that, in neat blends, the photocurrent of the polymer with siloxy side chains (PII2T-Si) is 4 times greater than that in blends using the polymer with branched aliphatic side chains (PII2T-ref). This difference is due to a larger out-of-plane hole mobility for PII2T-Si brought about by a largely face-on crystallite orientation as well as more optimal nanoscale polymer:PC71BM mixing. However, upon incorporating a common processing additive, 1,8-diiodooctane (DIO), into the spin-casting blend solution and following optimization, the PII2T-ref:PC71BM OPV device performance undergoes a large improvement and becomes the better-performing device, almost independent of DIO concentration (>1%). We find that the precise amount of DIO plays a larger role in determining the efficiency of PII2T-Si:PC71BM, and even at its maximum, the device performance lags behind optimized PII2T-ref:PC71BM blends. Using a combination of atomic force microscopy and small- and wide-angle X-ray scattering, we are able to elucidate the morphological modifications associated with the DIO-induced changes in both the nanoscale morphology and the molecular packing in blend films. © 2012 American Chemical Society.

  7. Polymer/metal nanocomposites for biomedical applications.

    Science.gov (United States)

    Zare, Yasser; Shabani, Iman

    2016-03-01

    Polymer/metal nanocomposites consisting of polymer as matrix and metal nanoparticles as nanofiller commonly show several attractive advantages such as electrical, mechanical and optical characteristics. Accordingly, many scientific and industrial communities have focused on polymer/metal nanocomposites in order to develop some new products or substitute the available materials. In the current paper, characteristics and applications of polymer/metal nanocomposites for biomedical applications are extensively explained in several categories including strong and stable materials, conductive devices, sensors and biomedical products. Moreover, some perspective utilizations are suggested for future studies. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. Structural Modifications and Photophysical Studies of Fluorescent Conjugated Polymers for Solid State Sensor Development

    Science.gov (United States)

    Chen, Anting

    Fluorescent conjugated polymers (FCPs) represent an exciting area of research in chemosensors and biosensors. Previously, the polymer tmeda-PPETE, N,N,N'-trimethylethylenediamino (tmeda) receptors on a poly[2,5-thiophenediyl-1,2-ethynediyl-1,4-phenylenediyl-1,2-ethynediyl] (PPETE) backbone, showed significant quenching when copper(II) was added. Tmeda-PPETE polymer preloaded with copper(II) was found to be a fluorescent "turn-on" sensor for iron cations. Additional investigation of this metallopolymer revealed a selective sensory system toward carbonate and phosphorus anions through a competitive binding of copper(II) between the polymer tmeda-PPETE and the anions. Fluorescent turn-on response under systematically varied pH was affected by the equilibrium shift of the ionization of polyprotic ions. A sterically hindered pentiptycene group was introduced to the PPETE polymer backbone aiming to reduce aggregation and self-quenching in the solid state. A new FCP, tmeda-PPpETE (poly[(pentiptycene ethynylene)-alt-(thienylene ethynylene)] with tmeda receptors, has been designed and synthesized via Sonogashira cross-coupling reaction. Absorption and emission spectra of tmeda-PPpETE showed blue shifting from tmeda-PPETE, suggesting increased rigidity of polymer backbone. Tmeda-PPpETE showed a high selectivity towards copper(II) with improved sensitivity compared to tmeda-PPETE. The fluorescent quenching response is over 120-fold at emission maximum, and the detection limit is 1.04 ppb, significantly lower than the EPA action level of 1.3 ppm for copper(II). A small turn-off fluorescent response of tmeda-PPpETE was also observed upon addition of iron cations. To further investigate the interaction between pentiptycene containing polymers and iron cations, tmpda-PPpETE containing N,N,N'-trimethylpropylenediamino (tmpda) receptors was designed and synthesized. The absorption and emission spectra for tmpda-PPpETE were analogous to those of tmeda-PPpETE, with a higher quantum

  9. Effects of polarons on static polarizabilities and second order hyperpolarizabilities of conjugated polymers

    International Nuclear Information System (INIS)

    Wang Ya-Dong; Meng Yan; Di Bing; Wang Shu-Ling; An Zhong

    2010-01-01

    According to the one-dimensional tight-binding Su—Schrieffer—Heeger model, we have investigated the effects of charged polarons on the static polarizability, α xx , and the second order hyperpolarizabilities, γ xxxx , of conjugated polymers. Our results are consistent qualitatively with previous ab initio and semi-empirical calculations. The origin of the universal growth is discussed using a local-view formalism that is based on the local atomic charge derivatives. Furthermore, combining the Su-Schrieffer-Heeger model and the extended Hubbard model, we have investigated systematically the effects of electron-electron interactions on α xx and γ xxxx of charged polymer chains. For a fixed value of the nearest-neighbour interaction V, the values of α xx and γ xxxx increase as the on-site Coulomb interaction U increases for U c and decrease with U for U > U c , where U c is a critical value of U at which the static polarizability or the second order hyperpolarizability reaches a maximal value of α max or γ max . It is found that the effect of the e-e interaction on the value of α xx is dependent on the ratio between U and V for either a short or a long charged polymer. Whereas, that effect on the value of γ xxxx is sensitive both to the ratio of U to V and to the size of the molecule. (rapid communication)

  10. Inkjet printing of conjugated polymer precursors on paper substrates for colorimetric sensing and flexible electrothermochromic display.

    Science.gov (United States)

    Yoon, Bora; Ham, Dae-Young; Yarimaga, Oktay; An, Hyosung; Lee, Chan Woo; Kim, Jong-Man

    2011-12-08

    Inkjet-printable aqueous suspensions of conjugated polymer precursors are developed for fabrication of patterned color images on paper substrates. Printing of a diacetylene (DA)-surfactant composite ink on unmodified paper and photopaper, as well as on a banknote, enables generation of latent images that are transformed to blue-colored polydiacetylene (PDA) structures by UV irradiation. Both irreversible and reversible thermochromism with the PDA printed images are demonstrated and applied to flexible and disposable sensors and to displays. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Functional supramolecular polymers for biomedical applications.

    Science.gov (United States)

    Dong, Ruijiao; Zhou, Yongfeng; Huang, Xiaohua; Zhu, Xinyuan; Lu, Yunfeng; Shen, Jian

    2015-01-21

    As a novel class of dynamic and non-covalent polymers, supramolecular polymers not only display specific structural and physicochemical properties, but also have the ability to undergo reversible changes of structure, shape, and function in response to diverse external stimuli, making them promising candidates for widespread applications ranging from academic research to industrial fields. By an elegant combination of dynamic/reversible structures with exceptional functions, functional supramolecular polymers are attracting increasing attention in various fields. In particular, functional supramolecular polymers offer several unique advantages, including inherent degradable polymer backbones, smart responsiveness to various biological stimuli, and the ease for the incorporation of multiple biofunctionalities (e.g., targeting and bioactivity), thereby showing great potential for a wide range of applications in the biomedical field. In this Review, the trends and representative achievements in the design and synthesis of supramolecular polymers with specific functions are summarized, as well as their wide-ranging biomedical applications such as drug delivery, gene transfection, protein delivery, bio-imaging and diagnosis, tissue engineering, and biomimetic chemistry. These achievements further inspire persistent efforts in an emerging interdisciplin-ary research area of supramolecular chemistry, polymer science, material science, biomedical engineering, and nanotechnology. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Electron beam irradiation crosslinked hydrogels based on tyramine conjugated gum tragacanth.

    Science.gov (United States)

    Tavakol, Moslem; Dehshiri, Saeedeh; Vasheghani-Farahani, Ebrahim

    2016-11-05

    In the present study, electron beam irradiation was applied to prepare a chemically crosslinked hydrogel based on tyramine conjugated gum tragacanth. Then, the gel content, swelling behavior and cytotoxicity of the hydrogels were evaluated. The gel content of the hydrogels was in the range of 75-85%. Equilibrium swelling degree of the hydrogels decreased from 51 to 14 with increasing polymer concentration and irradiation dose. Moisture retention capability of the hydrogels after 5h incubation at 37°C was in the range of 45-52 that is comparable with of commercial hydrogels. The cytotoxicity analysis showed the good biocompatibility of hydrogels. These results indicated that electron beam irradiation is a promising method to prepare chemically crosslinked tyramine conjugated gum tragacanth hydrogels for biomedical applications. Also, the versatility of electron beam irradiation for crosslinking of a variety of polymers possessing tyramine groups was demonstrated. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Interaction study on bovine serum albumin physically binding to silver nanoparticles: Evolution from discrete conjugates to protein coronas

    Energy Technology Data Exchange (ETDEWEB)

    Guo, Jun; Zhong, Ruibo; Li, Wanrong; Liu, Yushuang; Bai, Zhijun; Yin, Jun; Liu, Jingran; Gong, Pei [Agricultural Nanocenter, School of Life Science, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot 010018 (China); Zhao, Xinmin, E-mail: zhao.xinmin@hotmail.com [School of Foreign Language, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot 010018 (China); Zhang, Feng, E-mail: fengzhang1978@hotmail.com [Agricultural Nanocenter, School of Life Science, Inner Mongolia Agricultural University, 306 Zhaowuda Road, Hohhot 010018 (China)

    2015-12-30

    Graphical abstract: With the non-uniform coating of amphiphilic polymer, the silver nanoparticles (AgNPs) can form protein coronas which can become discrete protein–nanoparticle conjugates when controlling the protein–nanoparticle molar ratios. The protein's conformational changes upon binding NPs was also studied by both circular dichroism and three-dimensional fluorescence spectroscopy. - Highlights: • The amphiphilic polymer coating can not only transfer hydrophobic NPs into water soluble, but also providing a thick shell responsible for the strong physisorption to proteins without significantly changing their spatial conformations. • NP with discrete proteins can be simply obtained by a simple mixing procedure followed by a gel electrophoresis separation, and the resulting conjugates are robust enough to resist common separation techniques like gel electrophoresis. • In combination with the universal amphiphilic polymer coating strategy and the physisorption mediated protein–NP conjugation, proteins like BSA can be effectively conjugated to different materials such as noble metal, semiconductor and magnetic NPs. • In contrast to chemical coupling methods, the physisorption mediated protein–NP conjugation holds facile, robust and reversible advantages, which may find wide applications in nano-biomedicine field. - Abstract: The nanostructures formed by inorganic nanoparticles together with organic molecules especially biomolecules have attracted increasing attention from both industries and researching fields due to their unique hybrid properties. In this paper, we systemically studied the interactions between amphiphilic polymer coated silver nanoparticles and bovine serum albumins by employing the fluorescence quenching approach in combination with the Stern-Volmer and Hill equations. The binding affinity was determined to 1.30 × 10{sup 7} M{sup −1} and the interaction was spontaneously driven by mainly the van der Waals force and

  14. Electrical properties of a new sulfur-containing polymer for optoelectronic application

    Science.gov (United States)

    ElAkemi, ElMehdi; Jaballah, Nejmeddine; Ouada, Hafedh Ben; Majdoub, Mustapha

    2015-06-01

    An original polythiophene derivative was characterized to develop the optoelectronic properties of sulfur-containing π-conjugated polymer. The optical properties of the polymer were investigated by UV-visible absorption spectroscopy and atomic force microscopy. Investigations of the electrical characteristics of polymer diodes are reported. We present current-voltage characteristics and impedance spectroscopy measurements performed on partially sulfur-containing thin films in sandwich structure ITO/sulfur-containing polymer/Al. The conduction mechanisms in these layers are identified to be a space-charge-limited current. The AC electrical transport of the sulfur-containing polymer is studied as a function of frequency (100 Hz-10 MHz) and temperature in impedance spectroscopy analyses. We interpreted Cole-Cole plots in terms of the equivalent circuit model as a single parallel resistance and a capacitance network in series with a relatively small resistance. The evolution of the electrical parameters deduced from fitting of the experimental data is discussed.

  15. Facile synthesis of conjugated polymeric Schiff base as negative electrodes for lithium ion batteries

    International Nuclear Information System (INIS)

    Ye, Haijun; Jiang, Fangqing; Li, Hongqin; Xu, Zheng; Yin, Jiao; Zhu, Hui

    2017-01-01

    Graphical abstract: Polymeric Schiff base (PSB) exhibits a stable cyclability as an organic Li-ion battery anode Display Omitted -- Highlights: •A conjugated Schiff base polymer has been synthesized by a solid-phase reaction. •The polymer suppresses the dissolution of organic monomer into the organic electrolyte. •The polymer demonstrates high reversible capacity and excellent cyclic performance. -- Abstract: The redox-active organic compounds show great potentials as anodes for high energy density Li-ion batteries (LIBs), comparing with the traditional transition metal-based inorganic compounds. However, the inevitable dissolution behaviors of these organics in organic electrolyte will arouse the recession in their cycling stabilities. To circumvent this problem, we successfully applied an electrochemically active imine group to connect the carbonyl compound to form conjugated polymer, where the occurrence of multi-electron reactions suppressed the dissolution of anthraquinone in the organic electrolyte with improved cycling stability and high capacity for LIBs. In detail, by virtue of a facile solid-phase reaction between 1, 4-diaminoanthraquinone (14DAAQ) and p-phthalaldehyde (PPD), a highly conjugated polymeric Schiff base (PSB) was synthesized. The obtained PSB exhibited a reversible specific capacity of 175 mAh g −1 at a current density of 10 mA g −1 . In addition, after 100 cycles, a cycling stability with 90% capacity retention can be maintained, manifesting a promising application of the organic material in high performance anodes for LIBs.

  16. Covalently bound conjugates of albumin and heparin: Synthesis, fractionation and characterization

    NARCIS (Netherlands)

    Hennink, Wim E.; Feijen, Jan; Ebert, Charles D.; Kim, Sung Wan

    1983-01-01

    Covalently bound conjugates of human serum albumin and heparin were prepared as compounds which could improve the blood-compatibility of polymer surfaces either by preadsorption or by covalent coupling of the conjugates onto blood contacting surfaces. The conjugates (10–16 weight % of heparin) were

  17. Fluorescent molecularly imprinted polymer thin films for specific protein detection prepared with dansyl ethylenediamine-conjugated O-acryloyl L-hydroxyproline.

    Science.gov (United States)

    Inoue, Yuki; Kuwahara, Atsushi; Ohmori, Kohei; Sunayama, Hirobumi; Ooya, Tooru; Takeuchi, Toshifumi

    2013-10-15

    Protein-imprinted polymers, capable of specific transduction of protein binding events into fluorescent signal change, were designed and synthesized by using dansyl ethylenediamine-conjugated O-acryloyl L-hydroxyproline (Hyp-En-Dans). Human serum albumin (HSA) was used as a model target protein and HSA-imprinted polymers (HSA-IP) were prepared on glass substrates. Specific fluorescence change was observed for HSA binding on the imprinted polymer thin film, whereas a weaker response was observed for other proteins, including bovine serum albumin, chymotrypsin, lysozyme, and avidin. The binding specificity was found to derive from the rigid structure of the hydrogen-bondable pyrrolidine moiety. Compared with SPR measurements, the non-specific binding caused by the polymer matrix and/or randomly located fluorescent monomer residues that did not compose specific binding sites did not contribute to the observed fluorescence change. These results revealed that the proposed protein-imprinting technique using Hyp-En-Dans could provide a highly selective protein-sensing platform, in which only specific binding events would be detected by fluorescent measurements. Copyright © 2013 Elsevier B.V. All rights reserved.

  18. The effect of changes in π-conjugated terthienyl systems using thienyl and ethylenedioxybenzene functionalized thieno[3,4-b]pyrazine precursors: Multicolored low band gap polymers

    International Nuclear Information System (INIS)

    Tarkuc, Simge; Unver, Elif Kose; Udum, Yasemin Arslan; Tanyeli, Cihangir; Toppare, Levent

    2010-01-01

    New classes of thieno[3,4-b]pyrazines containing thienyl and ethylenedioxy phenyl units on electron-withdrawing moieties of π-conjugated terthienyl were synthesized. The effect of structural differences on electrochemical and optoelectronic properties of the resulting polymers was investigated. Changes in the electronic nature of the functional groups enable to tune the electrochemical properties of the π-conjugated terthienyl monomers by lowering oxidation potential from 0.62 V (DTTP) to 0.56 V (DBTP). Spectroelectrochemical analyses revealed that the neutral polymer (PDBTP) is dark green in its neutral state revealing π-π* transitions in two well-separated bands at 410 and 751 nm. The electronic band gap of polymer, defined as the onset of the π-π* transition, is found to be 1.0 eV. Using the thienyl unit instead of ethylenedioxy phenyl, a red shift in the band gap (0.95 eV) is observed. The polymer, PDTTP, exhibits multicolor electrochromism and can be switched between a dark yellow neutral state, a green intermediate state, and a brown oxidized state. PDBTP also shows a multicolored electrochromic behavior with three distinct states: dark green at the neutral state, a brown intermediate state, and a brown-violet oxidized state.

  19. Entanglement of conjugated polymer chains influences molecular self-assembly and carrier transport

    KAUST Repository

    Zhao, Kui; Khan, Hadayat Ullah; Li, Ruipeng; Su, Yisong; Amassian, Aram

    2013-01-01

    The influence of polymer entanglement on the self-assembly, molecular packing structure, and microstructure of low-Mw (lightly entangled) and high-Mw (highly entangled) poly (3-hexylthiophene) (P3HT), and the carrier transport in thin-film transistors, are investigated. The polymer chains are gradually disentangled in a marginal solvent via ultrasonication of the polymer solution, and demonstrate improved diffusivity of precursor species (coils, aggregates, and microcrystallites), enhanced nucleation and crystallization of P3HT in solution, and self-assembly of well-ordered and highly textured fibrils at the solid-liquid interface. In low-Mw P3HT, reducing chain entanglement enhances interchain and intrachain ordering, but reduces the interconnectivity of ordered domains (tie molecules) due to the presence of short chains, thus deteriorating carrier transport even in the face of improving crystallinity. Reducing chain entanglement in high-Mw P3HT solutions increases carrier mobility up to ≈20-fold, by enhancing interchain and intrachain ordering while maintaining a sufficiently large number of tie molecules between ordered domains. These results indicate that charge carrier mobility is strongly governed by the balancing of intrachain and interchain ordering, on the one hand, and interconnectivity of ordered domains, on the other hand. In high-Mw P3HT, intrachain and interchain ordering appear to be the key bottlenecks to charge transport, whereas in low-Mw P3HT, the limited interconnectivity of the ordered domains acts as the primary bottleneck to charge transport. Conjugated polymer chains of poly(3-hexylthiophene) (P3HT) are gradually disentangled in solution and trends in carrier transport mechanisms in organic thin film transistors for low- and high-molecular weight P3HT are investigated. While intrachain and interchain ordering within ordered domains are the key bottlenecks to charge transport in high-Mw P3HT films, the limited interconnectivity of ordered

  20. Entanglement of conjugated polymer chains influences molecular self-assembly and carrier transport

    KAUST Repository

    Zhao, Kui

    2013-06-26

    The influence of polymer entanglement on the self-assembly, molecular packing structure, and microstructure of low-Mw (lightly entangled) and high-Mw (highly entangled) poly (3-hexylthiophene) (P3HT), and the carrier transport in thin-film transistors, are investigated. The polymer chains are gradually disentangled in a marginal solvent via ultrasonication of the polymer solution, and demonstrate improved diffusivity of precursor species (coils, aggregates, and microcrystallites), enhanced nucleation and crystallization of P3HT in solution, and self-assembly of well-ordered and highly textured fibrils at the solid-liquid interface. In low-Mw P3HT, reducing chain entanglement enhances interchain and intrachain ordering, but reduces the interconnectivity of ordered domains (tie molecules) due to the presence of short chains, thus deteriorating carrier transport even in the face of improving crystallinity. Reducing chain entanglement in high-Mw P3HT solutions increases carrier mobility up to ≈20-fold, by enhancing interchain and intrachain ordering while maintaining a sufficiently large number of tie molecules between ordered domains. These results indicate that charge carrier mobility is strongly governed by the balancing of intrachain and interchain ordering, on the one hand, and interconnectivity of ordered domains, on the other hand. In high-Mw P3HT, intrachain and interchain ordering appear to be the key bottlenecks to charge transport, whereas in low-Mw P3HT, the limited interconnectivity of the ordered domains acts as the primary bottleneck to charge transport. Conjugated polymer chains of poly(3-hexylthiophene) (P3HT) are gradually disentangled in solution and trends in carrier transport mechanisms in organic thin film transistors for low- and high-molecular weight P3HT are investigated. While intrachain and interchain ordering within ordered domains are the key bottlenecks to charge transport in high-Mw P3HT films, the limited interconnectivity of ordered

  1. A Thieno[2,3-b]pyridine-Flanked Diketopyrrolopyrrole Polymer as an n-Type Polymer Semiconductor for All-Polymer Solar Cells and Organic Field-Effect Transistors

    KAUST Repository

    Chen, Hung-Yang

    2017-12-28

    A novel fused heterocycle-flanked diketopyrrolopyrrole (DPP) monomer, thieno[2,3-b]pyridine diketopyrrolopyrrole (TPDPP), was designed and synthesized. When copolymerized with 3,4-difluorothiophene using Stille coupling polymerization, the new polymer pTPDPP-TF possesses a highly planar conjugated polymer backbone due to the fused thieno[2,3-b]pyridine flanking unit that effectively alleviates the steric hindrance with both the central DPP core and the 3,4-difluorothiophene repeat unit. This new polymer exhibits a high electron affinity (EA) of −4.1 eV and was successfully utilized as an n-type polymer semiconductor for applications in organic field-effect transistors (OFETs) and all polymer solar cells. A promising n-type charge carrier mobility of 0.1 cm2 V–1 s–1 was obtained in bottom-contact, top-gate OFETs, and a power conversion efficiency (PCE) of 2.72% with a high open-circuit voltage (VOC) of 1.04 V was achieved for all polymer solar cells using PTB7-Th as the polymer donor.

  2. A Thieno[2,3-b]pyridine-Flanked Diketopyrrolopyrrole Polymer as an n-Type Polymer Semiconductor for All-Polymer Solar Cells and Organic Field-Effect Transistors

    KAUST Repository

    Chen, Hung-Yang; Nikolka, Mark; Wadsworth, Andrew; Yue, Wan; Onwubiko, Ada; Xiao, Mingfei; White, Andrew J. P.; Baran, Derya; Sirringhaus, Henning; McCulloch, Iain

    2017-01-01

    A novel fused heterocycle-flanked diketopyrrolopyrrole (DPP) monomer, thieno[2,3-b]pyridine diketopyrrolopyrrole (TPDPP), was designed and synthesized. When copolymerized with 3,4-difluorothiophene using Stille coupling polymerization, the new polymer pTPDPP-TF possesses a highly planar conjugated polymer backbone due to the fused thieno[2,3-b]pyridine flanking unit that effectively alleviates the steric hindrance with both the central DPP core and the 3,4-difluorothiophene repeat unit. This new polymer exhibits a high electron affinity (EA) of −4.1 eV and was successfully utilized as an n-type polymer semiconductor for applications in organic field-effect transistors (OFETs) and all polymer solar cells. A promising n-type charge carrier mobility of 0.1 cm2 V–1 s–1 was obtained in bottom-contact, top-gate OFETs, and a power conversion efficiency (PCE) of 2.72% with a high open-circuit voltage (VOC) of 1.04 V was achieved for all polymer solar cells using PTB7-Th as the polymer donor.

  3. Photoluminescence and solid state properties of rigid pi- conjugated polymers with applications to LED: Alkyl- substituted p-phenyleneethynylene polymers and triblock copolymers

    Science.gov (United States)

    Huang, Wen-Yao

    A series of substituted poly(p-phenyleneethynylene)s, PPE, were synthesized by alkyne metathesis. The substituents dibutyl (a), dioctyl (b), ditetradecyl (c), di-2-ethylhexyl (d) and di-2-cyclohexylethyl; (e)were placed on the 2,5 positions of the phenyl rings. X-ray diffraction studies indicated that the main chains of each polymer were arranged in regular, layered arrays. Liquid crystalline structures were observed by polarized optical microscopy in PPE 4b, 4c and 4d. The temperatures of isotropization of the liquid crystalline structures coincided with the disordering temperatures determined by differential scanning calorimetry. The UV absorption spectra showed a gradual blue shift of the λmax for all these polymers, suggesting a decrease in the electronic delocalization along the chain as the size and geometry of the side group changed. The photoluminescence spectra in dilute toluene solutions are consistent with vibronic coupling and emission from localized excited states. The emission spectra of thin films show characteristics typical of excimer or aggregate formation in the solid state. Lastly, an improved method of molecular weight determination by end group analysis was devised. Molecular organization and orientation in thin films (~100 nm) of a triblock copolymer, PPEPEG, was studied. The morphology of the thin film can be visualized as consisting of PMMA as the major phase in which domains of vertically oriented triblock copolymers are dispersed with PEG groups facing the air-film interface. The molecular and supramolecular structure of a series of well-defined fully conjugated poly(2,5- diakyl-p-phenyleneethynylene)s, PPE, in toluene has been studied in the sol state and in the gel state by surface tension and photoluminescence measurements. Poly (2,6[4- phenyl quinoline]), I, and poly (2,6[p-phenylene] 4- phenyl quinoline), II, were synthesized by the self- condensation of 5-acetyl-2-aminobezophenone and 4-amino- 4 '-acetyl-3-benzoyl biphenyl

  4. Surface conjugation of poly (dimethyl siloxane) with itaconic acid-based materials for antibacterial effects

    Science.gov (United States)

    Birajdar, Mallinath S.; Cho, Hyunjoo; Seo, Youngmin; Choi, Jonghoon; Park, Hansoo

    2018-04-01

    Poly (dimethyl siloxane) (PDMS) is widely used in various biomedical applications. However, the PDMS surface is known to cause bacterial adhesion and protein absorption issues due to its high hydrophobicity. Therefore, the development of antibacterial and anti-protein products is necessary to prevent these problems. In this study, to improve its antibacterial property and prevent protein adsorption, PDMS surfaces were conjugated with itaconic acid (IA) and poly (itaconic acid) (PIA) via a chemical method. Additionally, IA and PIA were physically blended with PDMS to compare the antibacterial properties of these materials with those of the chemically conjugated PDMS surfaces. The successful synthesis of the PIA polymer structure was confirmed by proton nuclear magnetic resonance (1H NMR) spectroscopy. The successful conjugation of IA and PIA on PDMS was confirmed by attenuated total reflection-Fourier transform infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), water contact angle measurements, and microbicinchoninic acid (BCA) protein assay analyses. The PDMS surfaces functionalized with IA and PIA by the conjugation method better prevented protein adsorption than the bare PDMS. Therefore, these surface-conjugated PDMS can be used in various biomedical applications.

  5. EGF Functionalized Polymer-Coated Gold Nanoparticles Promote EGF Photostability and EGFR Internalization for Photothermal Therapy.

    Directory of Open Access Journals (Sweden)

    Catarina Oliveira Silva

    Full Text Available The application of functionalized nanocarriers on photothermal therapy for cancer ablation has wide interest. The success of this application depends on the therapeutic efficiency and biocompatibility of the system, but also on the stability and biorecognition of the conjugated protein. This study aims at investigating the hypothesis that EGF functionalized polymer-coated gold nanoparticles promote EGF photostability and EGFR internalization, making these conjugated particles suitable for photothermal therapy. The conjugated gold nanoparticles (100-200 nm showed a plasmon absorption band located within the near-infrared range (650-900 nm, optimal for photothermal therapy applications. The effects of temperature, of polymer-coated gold nanoparticles and of UVB light (295nm on the fluorescence properties of EGF have been investigated with steady-state and time-resolved fluorescence spectroscopy. The fluorescence properties of EGF, including the formation of Trp and Tyr photoproducts, is modulated by temperature and by the intensity of the excitation light. The presence of polymeric-coated gold nanoparticles reduced or even avoided the formation of Trp and Tyr photoproducts when EGF is exposed to UVB light, protecting this way the structure and function of EGF. Cytotoxicity studies of conjugated nanoparticles carried out in normal-like human keratinocytes showed small, concentration dependent decreases in cell viability (0-25%. Moreover, conjugated nanoparticles could activate and induce the internalization of overexpressed Epidermal Growth Factor Receptor in human lung carcinoma cells. In conclusion, the gold nanoparticles conjugated with Epidermal Growth Factor and coated with biopolymers developed in this work, show a potential application for near infrared photothermal therapy, which may efficiently destroy solid tumours, reducing the damage of the healthy tissue.

  6. EGF Functionalized Polymer-Coated Gold Nanoparticles Promote EGF Photostability and EGFR Internalization for Photothermal Therapy

    Science.gov (United States)

    Silva, Catarina Oliveira; Petersen, Steffen B.; Reis, Catarina Pinto; Rijo, Patrícia; Molpeceres, Jesús; Fernandes, Ana Sofia; Gonçalves, Odete; Gomes, Andreia C.; Correia, Isabel; Vorum, Henrik; Neves-Petersen, Maria Teresa

    2016-01-01

    The application of functionalized nanocarriers on photothermal therapy for cancer ablation has wide interest. The success of this application depends on the therapeutic efficiency and biocompatibility of the system, but also on the stability and biorecognition of the conjugated protein. This study aims at investigating the hypothesis that EGF functionalized polymer-coated gold nanoparticles promote EGF photostability and EGFR internalization, making these conjugated particles suitable for photothermal therapy. The conjugated gold nanoparticles (100–200 nm) showed a plasmon absorption band located within the near-infrared range (650–900 nm), optimal for photothermal therapy applications. The effects of temperature, of polymer-coated gold nanoparticles and of UVB light (295nm) on the fluorescence properties of EGF have been investigated with steady-state and time-resolved fluorescence spectroscopy. The fluorescence properties of EGF, including the formation of Trp and Tyr photoproducts, is modulated by temperature and by the intensity of the excitation light. The presence of polymeric-coated gold nanoparticles reduced or even avoided the formation of Trp and Tyr photoproducts when EGF is exposed to UVB light, protecting this way the structure and function of EGF. Cytotoxicity studies of conjugated nanoparticles carried out in normal-like human keratinocytes showed small, concentration dependent decreases in cell viability (0–25%). Moreover, conjugated nanoparticles could activate and induce the internalization of overexpressed Epidermal Growth Factor Receptor in human lung carcinoma cells. In conclusion, the gold nanoparticles conjugated with Epidermal Growth Factor and coated with biopolymers developed in this work, show a potential application for near infrared photothermal therapy, which may efficiently destroy solid tumours, reducing the damage of the healthy tissue. PMID:27788212

  7. Enhancing the Photoluminescence Emission of Conjugated MEH-PPV by Light Processing

    KAUST Repository

    Botiz, Ioan

    2014-04-09

    We show here that treatment of thin films of conjugated polymers by illumination with light leads to an increase of the intensity of their photoluminescence by up to 42%. The corresponding enhancement of absorbance was much less pronounced. We explain this significant enhancement of photoluminescence by a planarization of the conjugated polymer chains induced by photoexcitations even below the glass transition temperature, possibly due to an increased conjugation length. Interestingly, the photoluminescence remains at the enhanced level for more than 71 h after treatment of the films by illumination with light, likely due to the fact that below the glass transition temperature no restoring force could return the conjugated chains into their initial conformational state. © 2014 American Chemical Society.

  8. Application of heat-balance integral method to conjugate thermal explosion

    Directory of Open Access Journals (Sweden)

    Novozhilov Vasily

    2009-01-01

    Full Text Available Conjugate thermal explosion is an extension of the classical theory, proposed and studied recently by the author. The paper reports application of heat-balance integral method for developing phase portraits for systems undergoing conjugate thermal explosion. The heat-balance integral method is used as an averaging method reducing partical differential equation problem to the set of first-order ordinary differential equations. The latter reduced problem allows natural interpretation in appropriately chosen phase space. It is shown that, with the help of heat-balance integral technique, conjugate thermal explosion problem can be described with a good accuracy by the set of non-linear first-order differential equations involving complex error function. Phase trajectories are presented for typical regimes emerging in conjugate thermal explosion. Use of heat-balance integral as a spatial averaging method allows efficient description of system evolution to be developed.

  9. A Possibility for Construction of an Iodine Cleaning System Based on Doping for π-Conjugated Polymers

    Directory of Open Access Journals (Sweden)

    Hiromasa Goto

    2011-05-01

    Full Text Available An iodine accumulation method using polyaniline (PANI and a textile composite is proposed. PANI/pulp paper sheets prepared by a paper making technique are suitable for iodine adsorption, because of good processability. The PANI-based paper sheets can be applied for iodine cleanup as air filters, water filters, and floorcloth. This concept may lead to a development of an iodine cleaning machine or iodine shield cloth based on π-conjugated polymer composites. In-situ vapor phase doping of iodine, observation of surface images, and IR measurements are carried out to examine iodine doping function for the PANI/pulp paper sheets.

  10. Alternative Thieno[3,2-b][1]benzothiophene Isoindigo Polymers for Solar Cell Applications

    KAUST Repository

    Neophytou, Marios

    2018-03-05

    This work reports the synthesis, characterization, photophysical, and photovoltaic properties of five new thieno[3,2-b][1]benzothiophene isoindigo (TBTI)-containing low bandgap donor-acceptor conjugated polymers with a series of comonomers and different side chains. When TBTI is combined with different electron-rich moieties, even small structural variations can have significant impact on thin film morphology of the polymer:phenyl C70 butyric acid methyl ester (PCBM) blends. More importantly, high-resolution electron energy loss spectroscopy is used to investigate the phase-separated bulk heterojunction domains, which can be accurately and precisely resolved, enabling an enhanced correlation between polymer chemical structure, photovoltaic device performance, and morphology.

  11. End Functionalized Nonionic Water-Dispersible Conjugated Polymers.

    Science.gov (United States)

    Zhan, Ruoyu; Liu, Bin

    2017-09-01

    2,7-Dibromofluorene monomers carrying two or four oligo(ethylene glycol) (OEG) side chains are synthesized. Heck coupling between the monomers and 1,4-divinylbenzene followed by end capping with [4-(4-bromophenoxy)butyl]carbamic acid tert-butyl ester leads to two nonionic water-dispersible poly(fluorene-alt-1,4-divinylenephenylene)s end-functionalized with amine groups after hydrolysis. In water, the polymer with a lower OEG density (P1) has poor water dispersibility with a quantum yield of 0.24, while the polymer with a higher OEG density (P2) possesses excellent water-dispersibility with a high quantum yield of 0.45. Both polymers show fluorescence enhancement and blue-shifted absorption and emission maxima in the presence of surfactant sodium dodecyl sulfate and dodecyltrimethylammonium bromide. The polymers are also resistant to ionic strength with minimal nonspecific interactions to bovine serum albumin. When biotin is incorporated into the end of the polymer backbones through N-hydroxysuccinimide/amine coupling reaction, the biotinylated polymers interact specifically with streptavidin on solid surface. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Solid-phase synthesis of protein-polymers on reversible immobilization supports.

    Science.gov (United States)

    Murata, Hironobu; Carmali, Sheiliza; Baker, Stefanie L; Matyjaszewski, Krzysztof; Russell, Alan J

    2018-02-27

    Facile automated biomacromolecule synthesis is at the heart of blending synthetic and biologic worlds. Full access to abiotic/biotic synthetic diversity first occurred when chemistry was developed to grow nucleic acids and peptides from reversibly immobilized precursors. Protein-polymer conjugates, however, have always been synthesized in solution in multi-step, multi-day processes that couple innovative chemistry with challenging purification. Here we report the generation of protein-polymer hybrids synthesized by protein-ATRP on reversible immobilization supports (PARIS). We utilized modified agarose beads to covalently and reversibly couple to proteins in amino-specific reactions. We then modified reversibly immobilized proteins with protein-reactive ATRP initiators and, after ATRP, we released and analyzed the protein polymers. The activity and stability of PARIS-synthesized and solution-synthesized conjugates demonstrated that PARIS was an effective, rapid, and simple method to generate protein-polymer conjugates. Automation of PARIS significantly reduced synthesis/purification timelines, thereby opening a path to changing how to generate protein-polymer conjugates.

  13. Stable and Efficient Organo-Metal Halide Hybrid Perovskite Solar Cells via π-Conjugated Lewis Base Polymer Induced Trap Passivation and Charge Extraction.

    Science.gov (United States)

    Qin, Ping-Li; Yang, Guang; Ren, Zhi-Wei; Cheung, Sin Hang; So, Shu Kong; Chen, Li; Hao, Jianhua; Hou, Jianhui; Li, Gang

    2018-03-01

    High-quality pinhole-free perovskite film with optimal crystalline morphology is critical for achieving high-efficiency and high-stability perovskite solar cells (PSCs). In this study, a p-type π-conjugated polymer poly[(2,6-(4,8-bis(5-(2-ethylhexyl) thiophen-2-yl)-benzo[1,2-b:4,5-b'] dithiophene))-alt-(5,5-(1',3'-di-2-thienyl-5',7'-bis(2-ethylhexyl) benzo[1',2'-c:4',5'-c'] dithiophene-4,8-dione))] (PBDB-T) is introduced into chlorobenzene to form a facile and effective template-agent during the anti-solvent process of perovskite film formation. The π-conjugated polymer PBDB-T is found to trigger a heterogeneous nucleation over the perovskite precursor film and passivate the trap states of the mixed perovskite film through the formation of Lewis adducts between lead and oxygen atom in PBDB-T. The p-type semiconducting and hydrophobic PBDB-T polymer fills in the perovskite grain boundaries to improve charge transfer for better conductivity and prevent moisture invasion into the perovskite active layers. Consequently, the PSCs with PBDB-T modified anti-solvent processing leads to a high-efficiency close to 20%, and the devices show excellent stability, retaining about 90% of the initial power conversion efficiency after 150 d storage in dry air. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Fluorescence polarization measures energy funneling in single light-harvesting antennas--LH2 vs conjugated polymers.

    Science.gov (United States)

    Camacho, Rafael; Tubasum, Sumera; Southall, June; Cogdell, Richard J; Sforazzini, Giuseppe; Anderson, Harry L; Pullerits, Tõnu; Scheblykin, Ivan G

    2015-10-19

    Numerous approaches have been proposed to mimic natural photosynthesis using artificial antenna systems, such as conjugated polymers (CPs), dendrimers, and J-aggregates. As a result, there is a need to characterize and compare the excitation energy transfer (EET) properties of various natural and artificial antennas. Here we experimentally show that EET in single antennas can be characterized by 2D polarization imaging using the single funnel approximation. This methodology addresses the ability of an individual antenna to transfer its absorbed energy towards a single pool of emissive states, using a single parameter called energy funneling efficiency (ε). We studied individual peripheral antennas of purple bacteria (LH2) and single CP chains of 20 nm length. As expected from a perfect antenna, LH2s showed funneling efficiencies close to unity. In contrast, CPs showed lower average funneling efficiencies, greatly varying from molecule to molecule. Cyclodextrin insulation of the conjugated backbone improves EET, increasing the fraction of CPs possessing ε = 1. Comparison between LH2s and CPs shows the importance of the protection systems and the protein scaffold of LH2, which keep the chromophores in functional form and at such geometrical arrangement that ensures excellent EET.

  15. Entanglements in Marginal Solutions: A Means of Tuning Pre-Aggregation of Conjugated Polymers with Positive Implications for Charge Transport

    KAUST Repository

    Hu, Hanlin

    2015-06-17

    The solution-processing of conjugated polymers, just like commodity polymers, is subject to solvent and molecular weight-dependent solubility, interactions and chain entanglements within the polymer, all of which can influence the crystallization and microstructure development in semi-crystalline polymers and consequently affect charge transport and optoelectronic properties. Disentanglement of polymer chains in marginal solvents was reported to work via ultrasonication, facilitating the formation of photophysically ordered polymer aggregates. In this contribution, we explore how a wide range of technologically relevant solvents and formulations commonly used in organic electronics influence chain entanglement and the aggregation behaviour of P3HT using a combination of rheological and spectrophotometric measurements. The specific viscosity of the solution offers an excellent indication of the degree of entanglements in the solution, which is found to be related to the solubility of P3HT in a given solvent. Moreover, deliberately disentangling the solution in the presence of solvophobic driving forces, leads consistently to formation of photophysically visible aggregates which is indicative of local and perhaps long range order in the solute. We show for a broad range of solvents and molecular weights that disentanglement ultimately leads to significant ordering of the polymer in the solid state and a commensurate increase in charge transport properties. In doing so we demonstrate a remarkable ability to tune the microstructure which has important implications for transport properties. We discuss its potential implications in the context of organic photovoltaics.

  16. Entanglements in Marginal Solutions: A Means of Tuning Pre-Aggregation of Conjugated Polymers with Positive Implications for Charge Transport

    KAUST Repository

    Hu, Hanlin; Zhao, Kui; Fernandes, Nikhil J.; Boufflet, Pierre; Bannock, James Henry; Yu, Liyang; de Mello, John C; Stingelin, Natalie; Heeney, Martin; Giannelis, Emmanuel P.; Amassian, Aram

    2015-01-01

    The solution-processing of conjugated polymers, just like commodity polymers, is subject to solvent and molecular weight-dependent solubility, interactions and chain entanglements within the polymer, all of which can influence the crystallization and microstructure development in semi-crystalline polymers and consequently affect charge transport and optoelectronic properties. Disentanglement of polymer chains in marginal solvents was reported to work via ultrasonication, facilitating the formation of photophysically ordered polymer aggregates. In this contribution, we explore how a wide range of technologically relevant solvents and formulations commonly used in organic electronics influence chain entanglement and the aggregation behaviour of P3HT using a combination of rheological and spectrophotometric measurements. The specific viscosity of the solution offers an excellent indication of the degree of entanglements in the solution, which is found to be related to the solubility of P3HT in a given solvent. Moreover, deliberately disentangling the solution in the presence of solvophobic driving forces, leads consistently to formation of photophysically visible aggregates which is indicative of local and perhaps long range order in the solute. We show for a broad range of solvents and molecular weights that disentanglement ultimately leads to significant ordering of the polymer in the solid state and a commensurate increase in charge transport properties. In doing so we demonstrate a remarkable ability to tune the microstructure which has important implications for transport properties. We discuss its potential implications in the context of organic photovoltaics.

  17. Direct observation of the ultrafast electron transfer process in a polymer/fullerene blend

    NARCIS (Netherlands)

    Cerullo, G.; Lanzani, G.; Silvestri, S. De; Brabec, Ch.J.; Zerza, G.; Sariciftci, N.S.; Hummelen, J.C.

    2000-01-01

    Photoinduced electron transfer in organic molecules is an extensively investigated topic both because of fundamental interest in the photophysics and for applications to artificial photosynthesis. Highly efficient ultrafast electron transfer from photoexcited conjugated polymers to C60 has been

  18. Study on the Antimicrobial Properties of Citrate-Based Biodegradable Polymers

    Directory of Open Access Journals (Sweden)

    Lee-Chun eSu

    2014-07-01

    Full Text Available Citrate-based polymers possess unique advantages for various biomedical applications since citric acid is a natural metabolism product, which is biocompatible and antimicrobial. In polymer synthesis, citric acid also provides multiple functional groups to control the crosslinking of polymers and active binding sites for further conjugation of biomolecules. Our group recently developed a number of citrate-based polymers for various biomedical applications by taking advantage of their controllable chemical, mechanical, and biological characteristics. In this study, various citric acid derived biodegradable polymers were synthesized and investigated for their physicochemical and antimicrobial properties. Results indicate that citric acid derived polymers reduced bacterial proliferation to different degrees based on their chemical composition. Among the studied polymers, poly(octamethylene citrate (POC showed approximately 70-80% suppression to microbe proliferation, owing to its relatively higher ratio of citric acid contents. Crosslinked urethane-doped polyester elastomers (CUPEs and biodegradable photoluminescent polymers (BPLPs also exhibited significant bacteria reduction of ~20% and ~50% for Staphylococcus aureus and Escherichia coli, respectively. Thus, the intrinsic antibacterial properties in citrate-based polymers enable them to inhibit bacteria growth without incorporation of antibiotics, silver nanoparticles, and other traditional bacteria-killing agents suggesting that they are unique beneficial materials for wound dressing, tissue engineering, and other potential medical applications where antimicrobial property is desired.

  19. Simulation Studies of LCST-like Phase Transitions in Elastin-like Polypeptides (ELPs) and Conjugates of ELP with Rigid Macromolecules

    Science.gov (United States)

    Condon, Joshua; Martin, Tyler; Jayaraman, Arthi

    We use atomistic (AA) and coarse-grained (CG) molecular dynamics simulations to elucidate the thermodynamic driving forces governing lower critical solution temperature (LCST)-like phase transition exhibited by elastin-like peptides (ELPs) and conjugates of ELP with other macromolecules. In the AA simulations, we study ELP oligomers in explicit water, and mark the transition as the temperature at which they undergo a change in ``hydration'' state. While AA simulations are restricted to small systems of short ELPs and do not capture the chain aggregation observed in experiments of ELPs, they guide the phenomenological CG model development by highlighting the solvent induced polymer-polymer effective interactions with changing temperature. In the CG simulations, we capture the LCST polymer aggregation by increasing polymer-polymer effective attractive interactions in an implicit solvent. We examine the impact of conjugating a block of LCST polymer to another rigid unresponsive macromolecular block on the LCST-like transition. We find that when multiple LCST polymers are conjugated to a rigid polymer block, increased crowding of the LCST polymers shifts the onset of chain aggregation to smaller effective polymer-polymer attraction compared to the free LCST polymers. These simulation results provide guidance on the design of conjugated bio-mimetic thermoresponsive materials, and shape the fundamental understanding of the impact of polymer crowding on phase behavior in thermoresponsive LCST polymer systems.

  20. Flexible organic/inorganic hybrid solar cells based on conjugated polymer and ZnO nanorod array

    International Nuclear Information System (INIS)

    Tong, Fei; Kim, Kyusang; Martinez, Daniel; Thapa, Resham; Ahyi, Ayayi; Williams, John; Park, Minseo; Kim, Dong-Joo; Lee, Sungkoo; Lim, Eunhee; Lee, Kyeong K

    2012-01-01

    We report on the photovoltaic characteristics of organic/inorganic hybrid solar cells fabricated on ‘flexible’ transparent substrates. The solar cell device is composed of ZnO nanorod array and the bulk heterojunction structured organic layer which is the blend of poly(3-hexylthiophene) (P3HT) and (6,6)-phenyl C61 butyric acid methyl ester (PCBM). The ZnO nanorod array was grown on indium tin oxide (ITO)-coated polyethylene terephthalate (PET) substrates via a low-temperature (85 °C) aqueous solution process. The blend solution consisting of conjugated polymer P3HT and fullerene PCBM was spin coated at a low spinning rate of 400 rpm on top of the ZnO nanorod array structure and then the photoactive layer was slow dried at room temperature in air to promote its infiltration into the nanorod network. As a top electrode, silver was sputtered on top of the photoactive layer. The flexible solar cell with the structure of PET/ITO/ZnO thin film/ZnO nanorods/P3HT:PCBM/Ag exhibited a photovoltaic performance with an open circuit voltage (V OC ) of 0.52 V, a short circuit current density (J SC ) of 9.82 mA cm −2 , a fill factor (FF) of 35% and a power conversion efficiency (η) of 1.78%. All the measurements were performed under 100 mW cm −2 of illumination with an air mass 1.5 G filter. To the best of our knowledge, this is the first presentation of investigation into the fabrication and characterization of organic/inorganic hybrid solar cells based on bulk heterojunction structured conjugated polymer/fullerene photoactive layer and ZnO nanorod array constructed on flexible transparent substrates. (paper)

  1. Applications of interface controlled pulsed-laser deposited polymer films in field-effect transistors

    Science.gov (United States)

    Adil, Danish; Ukah, Ndubuisi; Guha, Suchi; Gupta, Ram; Ghosh, Kartik

    2010-03-01

    Matrix assisted pulsed laser evaporation, a derivative of pulsed laser deposition (PLD), is an alternative method of depositing polymer and biomaterial films that allows homogeneous film coverage of high molecular weight organic materials for layer-by-layer growth without any laser induced damage. Polyfluorene (PF)-based conjugated polymers have attracted considerable attention in organic field-effect transistors (FETs). A co-polymer of PF (PFB) was deposited as a thin film using matrix assisted PLD employing a KrF excimer laser. Electrical characteristics of FETs fabricated using these PLD grown films were compared to those of FETs using spin-coated films. We show that threshold voltages, on/off ratios, and charge carrier motilities are significantly improved in PLD grown films. This is attributed to an improved dielectric-polymer interface.

  2. Fluctuating exciton localization in giant π-conjugated spoked-wheel macrocycles

    Science.gov (United States)

    Aggarwal, A. Vikas; Thiessen, Alexander; Idelson, Alissa; Kalle, Daniel; Würsch, Dominik; Stangl, Thomas; Steiner, Florian; Jester, Stefan-S.; Vogelsang, Jan; Höger, Sigurd; Lupton, John M.

    2013-11-01

    Conjugated polymers offer potential for many diverse applications, but we still lack a fundamental microscopic understanding of their electronic structure. Elementary photoexcitations (excitons) span only a few nanometres of a molecule, which itself can extend over microns, and how their behaviour is affected by molecular dimensions is not immediately obvious. For example, where is the exciton formed within a conjugated segment and is it always situated on the same repeat units? Here, we introduce structurally rigid molecular spoked wheels, 6 nm in diameter, as a model of extended π conjugation. Single-molecule fluorescence reveals random exciton localization, which leads to temporally varying emission polarization. Initially, this random localization arises after every photon absorption event because of temperature-independent spontaneous symmetry breaking. These fast fluctuations are slowed to millisecond timescales after prolonged illumination. Intramolecular heterogeneity is revealed in cryogenic spectroscopy by jumps in transition energy, but emission polarization can also switch without a spectral jump occurring, which implies long-range homogeneity in the local dielectric environment.

  3. Conformation Control of a Conjugated Polymer through Complexation with Bile Acids Generates Its Novel Spectral and Morphological Properties.

    Science.gov (United States)

    Tsuchiya, Youichi; Noguchi, Takao; Yoshihara, Daisuke; Roy, Bappaditya; Yamamoto, Tatsuhiro; Shinkai, Seiji

    2016-11-29

    Control of higher-order polymer structures attracts a great deal of interest for many researchers when they lead to the development of materials having various advanced functions. Among them, conjugated polymers that are useful as starting materials in the design of molecular wires are particularly attractive. However, an equilibrium existing between isolated chains and bundled aggregates is inevitable and has made their physical properties very complicated. As an attempt to simplify this situation, we previously reported that a polymer chain of a water-soluble polythiophene could be isolated through complexation with a helix-forming polysaccharide. More recently, a covalently self-threading polythiophene was reported, the main chain of which was physically protected from self-folding and chain-chain π-stacking. In this report, we wish to report a new strategy to isolate a water-soluble polythiophene and to control its higher-order structure by a supramolecular approach: that is, among a few bile acids, lithocholate can form stoichiometric complexes with cationic polythiophene to isolate the polymer chain, and the higher-order structure is changeable by the molar ratio. The optical and morphological studies have been thoroughly performed, and the resultant complex has been applied to the selective recognition of two AMP structural isomers.

  4. Thiophene fused azacoronenes: regioselective synthesis, self organization, charge transport, and its incorporation in conjugated polymers

    Science.gov (United States)

    Liu, Yi; He, Bo

    2015-09-15

    A regioselective synthesis of an azacoronene fused with two peripheral thiophene groups has been realized through a concise synthetic route. The resulting thienoazacoronene (TAC) derivatives show high degree of self-organization in solution, in single crystals, in the bulk, and in spuncast thin films. Spuncast thin film field-effect transistors of the TACs exhibited mobilities up to 0.028 cm.sup.2V.sup.-1 S.sup.-1, which is among the top field effect mobilities for solution processed discotic materials. Organic photovoltaic devices using TAC-containing conjugated polymers as the donor material exhibited a high open-circuit voltage of 0.89 V, which was ascribable to TAC's low-lying highest occupied molecular orbital energy level.

  5. Preparation of nanocrystals and nanocomposites of nanocrystal-conjugated polymer, and their photophysical properties in confined geometries

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Jun [Iowa State Univ., Ames, IA (United States)

    2007-01-01

    Semiconductors nanocrystals (NCs), also called quantum dots (QDs), have attracted tremendous interest over the past decade in the fields of physics, chemistry, and engineering. Due to the quantum-confined nature of QDs, the variation of particle size provides continuous and predictable changes in fluorescence emission. On the other hand, conjugated polymers (CPs) have been extensively studied for two decades due to their semiconductor-like optical and electronic properties. The electron and energy transfer between NCs and CPs occur in solar cells and light emitting diodes (LEDs), respectively. Placing CPs in direct contact with a NC (i.e., preparing NC-CP nanocomposites) carries advantage over cases where NC aggregation dominates. Such NC-CP nanocomposites possess a well-defined interface that significantly promotes the charge or energy transfer between these two components. However, very few studies have centered on such direct integration. We prepared NCs and NC-CP nanocomposites based on heck coupling and investigated the energy and charge transfer between semiconductor NCs (i.e., CdSe QDs), CPs (i.e., poly(3-hexyl thiophene) (P3HT)) in the nanocomposites in confined geometries. Two novel strategies were used to confine NC and/or NC-CP nanocomposites: (a) directly immobilizing nanohybrids, QDs and nanorods in nanoscopic porous alumina membrane (PAM) , and (b) confining the QDs and CPs in sphere-on-flat geometry to induce self-assembly. While investigating the confinement effect, gradient concentric ring patterns of high regularity form spontaneously simply by allowing a droplet of solution containing either conjugated polymer or semiconductor nanocrystal in a consecutive stick-slip mothion in a confined geometry. Such constrained evaporation can be utilized as a simple, cheap, and robust strategy for self-assembling various materials with easily tailored optical and electronic properties into spatially ordered, two-dimensional patterns. These self

  6. Synthesis and luminescent properties of new conjugated polymers based on poly(p-phenylene vinylene)

    Science.gov (United States)

    Gurge, Ronald Matthew

    The "push-pull" electronically substituted polymers poly(2 (5) -bromo-5 (2) -n-hexyloxy-1,4-phenylene vinylene), poly(2 (5) -chloro-5 (2) -n-hexyloxy-1,4-phenylene vinylene) and poly(2 (5) -fluoro-5 (2) -n-hexyloxy-1,4-phenylene vinylene) were synthesized by a soluble precursor method and were used to fabricate light emitting diode (LED) devices. Thermal elimination of the polyether precursors gives final conjugated polymers as flexible red films. Precursor polymers can be spin-cast from solutions onto indium/tin oxide (ITO) pretreated quartz plates, then thermally converted to the final red polymers. Light emitting diode fabrication is then completed by the thin film vapor deposition of calcium, followed by aluminum. LED devices of the "push-pull" polymers give light emission in the 620-635 nm range. Two fluorinated polymers, poly(2-fluoro-1,4-phenylene vinylene) and poly(2,5-difluoro-1,4-phenylene vinylene) were investigated for their electroluminescent (EL) properties. LED's using these materials as emissive layers show substantial EL wavelength shifts (560 nm and 600 nm, respectively) relative to emission from unsubstituted poly(1,4-phenylene vinylene) (565 nm). These differences in EL emission can be attributed to the electronic effects of fluorine substitution. Synthetic strategies were developed for copolymeric materials based on poly(1,4-phenylene vinylene). The alternating block copolymer, poly (1,8-octanedioxy-2,6-dimethoxy-1,4-phenylene-1,2-ethenylene-1,4-phenylene-1,2-ethenylene-1,4-phenylene-1,2-ethenylene- 3,5-dimethoxy-1,4-phenylene) was synthesized by a modified Wittig polymerization utilizing trialkyl phosphonium salts. This resulted in a regiospecific trans-olefination reaction when compared to polymeric materials synthesized through the use of common triaryl-phosphonium salts. Harsh post-Wittig isomerization procedures using Isb2 were bypassed as a result of the high trans-cis ratio of the final copolymer. It was fully characterized using the

  7. White light generation tuned by dual hybridization of nanocrystals and conjugated polymers

    International Nuclear Information System (INIS)

    Demir, Hilmi Volkan; Nizamoglu, Sedat; Ozel, Tuncay; Mutlugun, Evren; Huyal, Ilkem Ozge; Sari, Emre; Holder, Elisabeth; Tian Nan

    2007-01-01

    Dual hybridization of highly fluorescent conjugated polymers and highly luminescent nanocrystals (NCs) is developed and demonstrated in multiple combinations for controlled white light generation with high color rendering index (CRI) (> 80) for the first time. The generated white light is tuned using layer-by-layer assembly of CdSe/ZnS core-shell NCs closely packed on polyfluorene, hybridized on near-UV emitting nitride-based light emitting diodes (LEDs). The design, synthesis, growth, fabrication and characterization of these hybrid inorganic-organic white LEDs are presented. The following experimental realizations are reported: (i) layer-by-layer hybridization of yellow NCs (λ PL =580 nm) and blue polyfluorene (λ PL =439 nm) with tristimulus coordinates of (x, y)=(0.31, 0.27), correlated color temperature of T c =6962 K and CRI of R a =53.4; (ii) layer-by-layer assembly of yellow and green NCs (λ PL =580 and 540 nm) and blue polyfluorene (λ PL =439 nm) with (x, y)=(0.23, 0.30), T c =14395 K and R a =65.7; and (iii) layer-by-layer deposition of yellow, green and red NCs (λ PL =580, 540 and 620 nm) and blue polyfluorene (λ PL =439 nm) with (x, y)=(0.38, 0.39), T c =4052 K and R a = 83.0. The CRI is demonstrated to be well controlled and significantly improved by increasing multi-chromaticity of the NC and polymer emitters

  8. Labeling of DOTA-conjugated HPMA-based polymers with trivalent metallic radionuclides for molecular imaging.

    Science.gov (United States)

    Eppard, Elisabeth; de la Fuente, Ana; Mohr, Nicole; Allmeroth, Mareli; Zentel, Rudolf; Miederer, Matthias; Pektor, Stefanie; Rösch, Frank

    2018-02-27

    In this work, the in vitro and in vivo stabilities and the pharmacology of HPMA-made homopolymers were studied by means of radiometal-labeled derivatives. Aiming to identify the fewer amount and the optimal DOTA-linker structure that provides quantitative labeling yields, diverse DOTA-linker systems were conjugated in different amounts to HPMA homopolymers to coordinate trivalent radiometals Me(III)* = gallium-68, scandium-44, and lutetium-177. Short linkers and as low as 1.6% DOTA were enough to obtain labeling yields > 90%. Alkoxy linkers generally exhibited lower labeling yields than alkane analogues despite of similar chain length and DOTA incorporation rate. High stability of the radiolabel in all examined solutions was observed for all conjugates. Labeling with scandium-44 allowed for in vivo PET imaging and ex vivo measurements of organ distribution for up to 24 h. This study confirms the principle applicability of DOTA-HPMA conjugates for labeling with different trivalent metallic radionuclides allowing for diagnosis and therapy.

  9. Conjugated Polymer Solar Cells

    Science.gov (United States)

    2006-05-01

    thermal gravimetry analysis (TGA)............... 12 2.6 Photoluminescence (PL) spectroscopy... gravimetry analysis (TGA) Thermal analysis of polymer films has been accomplished by TGA and DSC methods with the aid of Perkin-Elmer Series 7 Analysers...The MEH-PPV/acceptor films were prepared by spin-casting of the resulting mixture (with or without precipitate ) on glass substrates of diameter 23 mm

  10. Hydrophobically associating polymers for oil field applications

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, K.C. [Taylor Industrial Research Inc., Victoria, BC (Canada); Nasr-El-Din, H.A. [Saudi Aramco, Dharhan (Saudi Arabia). R and D Center

    2007-07-01

    This paper discussed developments in water soluble hydrophobically associating polymers and their use in oilfield applications. The polymers are now being investigated for the potential application in enhanced oil recovery (EOR) as well as in completion fluids and profile modifications. The polymers are also purported to selectively reduce water permeability in sandstones. This study showed that the adsorption behaviour of the associating polymers is of greater significance than the rheology, particularly in non-damaging completion fluids and in profile modification. Issues related to acid diversion and conformance control applications were discussed, and drag reducing agents were reviewed. The study also discussed drilling and completion fluids; adsorption behaviour; rheology; and synthesis and characterization. It was concluded that gels are now being developed for conformance control and continued use for modification of water relative permeability. 35 refs., 5 figs.

  11. Photodynamic inactivation of bacteria using polyethylenimine-chlorin(e6) conjugates: Effect of polymer molecular weight, substitution ratio of chlorin(e6) and pH.

    Science.gov (United States)

    Huang, Liyi; Zhiyentayev, Timur; Xuan, Yi; Azhibek, Dulat; Kharkwal, Gitika B; Hamblin, Michael R

    2011-04-01

    Antimicrobial photodynamic therapy (APDT) is a novel technique to treat local infections. Previously we reported that the attachment of chlorin(e6) to polyethylenimine (PEI) polymers to form PEI-ce6 conjugates is an effective way to improve ce6 PDT activity against bacteria. The aim of this work was to explore how the polymer molecular weight, substitution ratio (SR) of ce6 and pH value affect the PDT efficacy. We have synthesized PEI-ce6(10) (MW = 60,000, SR = 1) and PEI-ce6(11) (MW = 60,000, SR = 5) and compared these with the previous PEI-ce6(9) (MW = 10,000, SR = 1). We tested the PDT efficacy of these three conjugates against Gram-negative E. coli and Gram-positive bacteria (S. aureus and E. fecalis) at three different pH values (5.0, 7.4, 10.0) that may affect the charge on both the bacterial cells and on the conjugate (that has both basic and acidic groups). PEI-ce6(9) and PEI-ce6(10) were the most effective against these tested bacteria. The PDT effect of all three conjugates depended on pH values. The effective order was pH = 10.0 > pH = 7.4 > pH = 5.0 on E. coli. For S. aureus and E. fecalis the order was pH = 5.0 > pH = 10.0 > pH = 7.4. PEI-ce6(11) PDT activity was worse than PEI-ce6(10) activity which is probably connected to the fact that ce6 molecules are self-quenched within the PEI-ce6(11) molecule. Ce6 quenching within the PEI-ce6 molecules was proved by analyzing fluorescence spectra of PEI-ce6 conjugates at different pH values. There were no differences in bacterial uptake between different pH values in three PEI-ce6 conjugates. We assume high pH (rather than low pH as was hypothesized) disaggregates the conjugates, so the higher pH was more effective than the lower pH against E. coli. But for Gram-positive bacteria, low pH was more effective possibly due to more overall positive charge on the conjugate. Copyright © 2011 Wiley-Liss, Inc.

  12. Interfacial molecular order of conjugated polymer in P3HT:ZnO bilayer photovoltaics and its impact on device performance

    KAUST Repository

    Wood, Sebastian

    2013-01-01

    Hybrid (organic-oxide) photovoltaic device performance is highly dependent on the nature and quality of the organic-oxide interface. This work investigates the details of interfacial morphology in terms of the molecular order of poly(3-hexylthiophene) (P3HT) at the planar interface with zinc oxide (ZnO) formed by pulsed laser deposition. Resonant Raman spectroscopy is employed as a powerful morphological probe for conjugated polymers to reveal that the interfacial P3HT is disrupted during the deposition process whereas the bulk polymer shows an increase in molecular order. External quantum efficiency measurements of P3HT:ZnO bilayer devices show that this disordered P3HT region is active in photocurrent generation. © 2013 AIP Publishing LLC.

  13. Novel HPC-ibuprofen conjugates: synthesis, characterization, thermal analysis and degradation kinetics

    International Nuclear Information System (INIS)

    Hussain, M.A.; Lodhi, B.A.; Abbas, K.

    2014-01-01

    Naturally occurring hydrophilic polysaccharides are advantageously used as drug carriers because they provide a mechanism to improve drug action. Hydroxypropylcellulose (HPC) is water-soluble, biocompatible and bears hydroxyl groups for drug conjugation outside the parent polymeric chains. This unique geometry allows the attachment of drug molecules with higher covalent loading. The HPC-Ibuprofen conjugates as macromolecular prodrugs were therefore synthesized employing homogenous and one pot reaction methodologies using p-toluenesulfonyl chloride in N,N-dimethylacetamide solvent at 80 degree C for 24 h under nitrogen atmosphere. The imidazole was used as a base for neutralization of acidic impurities. Present strategy appeared effective to get high yield (77-81%) and high degree of drug substitution (DS 0.88-1.40) onto the HPC polymer as determined by the acid-base titration and verified by 1H-NMR spectroscopy. The gel permeation chromatography has shown uni-modal absorption which indicates no significant degradation of polymer during reaction. Macromolecular prodrugs with different DS of ibuprofen were synthesized, purified, characterized and found soluble in organic solvents. From thermogravimetric analysis, initial, maximum and final degradation temperatures of the conjugates were calculated and compared for relative thermal stability. Thermal degradation kinetics was also studied and results have indicated that degradation of conjugates follows about first order kinetics as calculated by Kissinger model. The energy of activation was also found moderate 92.38, 99.34 and 87.34 kJ/mol as calculated using Friedman, Broido and Chang models. It was found that these novel prodrugs of ibuprofen were thermally stable therefore these may have potential pharmaceutical applications. (author)

  14. CONJUGATED POLYMERS AND POLYELECTROLYTES IN SOLAR PHOTOCONVERSION, Final Technical Report

    Energy Technology Data Exchange (ETDEWEB)

    Schanze, Kirk S [University of Florida

    2014-08-05

    This DOE-supported program investigated the fundamental properties of conjugated polyelectrolytes, with emphasis placed on studies of excited state energy transport, self-assembly into conjugated polyelectroyte (CPE) based films and colloids, and exciton transport and charge injection in CPE films constructed atop wide bandgap semiconductors. In the most recent grant period we have also extended efforts to examine the properties of low-bandgap donor-acceptor conjugated polyelectrolytes that feature strong visible light absorption and the ability to adsorb to metal-oxide interfaces.

  15. Albumin–Polymer–Drug Conjugates: Long Circulating, High Payload Drug Delivery Vehicles

    DEFF Research Database (Denmark)

    Smith, Anton Allen Abbotsford; Zuwala, Kaja; Pilgram, Oliver

    2016-01-01

    Albumin is an exquisite tool of nature used in biomedicine to achieve long blood residence time for drugs, but the payload it can carry is typically limited to one molecule per protein. In contrast, synthetic macromolecular prodrugs contain multiple copies of drugs per polymer chain but offer only...... a marginal increase in the circulation lifetime of the drugs. We combine the benefits of the two platforms and at the same time overcome their respective limitations. Specifically, we develop the synthesis of albumin–polymer–drug conjugates to obtain long circulating, high payload drug delivery vehicles....... In vivo data validate that albumin endows the conjugate with a blood residence time similar to that of the protein and well exceeding that of the polymer. Therapeutic activity of the conjugates is validated using prodrugs of panobinostat, an HIV latency reversal agent, in which case the conjugates matched...

  16. Conducting polymers: Synthesis and industrial applications

    Energy Technology Data Exchange (ETDEWEB)

    Gottesfeld, S. [Los Alamos National Laboratory, NM (United States)

    1995-05-01

    The Conducting Polymer project funded by the AIM Materials Program is developing new methods for the synthesis of electronically conducting polymers and is evaluating new industrial applications for these materials which will result in significant reductions in energy usage or industrial waste. The applications specifically addressed during FY 1994 are electrochemical capacitors and membranes for gas separation. As an active material in electrochemical capacitors, conducting polymers have the potential of storing large amounts of electrical energy in low cost materials. Such devices are needed in electronics for power failure back-up and peak power, in power supplies for filtering, and in electric vehicles for peak power and load leveling. As a gas electrically adapt the membrane for specific gas combinations. Potential energy savings in the US. for this application are estimated at 1 to 3 quads/yr.

  17. Transient photoconductivity and femtosecond nonlinear optical properties of a conjugated polymer-graphene oxide composite

    Energy Technology Data Exchange (ETDEWEB)

    Nalla, Venkatram; Ji Wei [Department of Physics, National University of Singapore, Singapore 117542 (Singapore); Polavarapu, Lakshminarayana; Manga, Kiran Kumar; Goh, Bee Min; Loh, Kian Ping; Xu Qinghua, E-mail: chmxqh@nus.edu.sg, E-mail: phyjiwei@nus.edu.sg [Department of Chemistry, National University of Singapore, Singapore 117543 (Singapore)

    2010-10-15

    A water soluble conjugated thiophene polymer, sodium salt of poly[2-(3-thienyl)ethoxy-4-butylsulfonate] (TPP), and graphene oxide (GO) composite film (GO-TPP) device was prepared. Transient photoconductivity measurements were carried out on the GO-TPP composite film using 150 ns laser pulses of 527 nm wavelength. Highly efficient photocurrent generation was observed from the GO-TPP film. The relationships of the film photoconductivity, photocurrent decay time and electron decay times with the incident light intensity were investigated. The photoconductive gain of the film was determined to be greater than 40% and to be independent of the light intensity. Furthermore, the femtosecond nonlinear optical properties of the GO-TPP film were measured using 800 nm femtosecond laser pulses and the composite film exhibited high nonlinear absorption and nonlinear refraction coefficients.

  18. Transient photoconductivity and femtosecond nonlinear optical properties of a conjugated polymer-graphene oxide composite

    International Nuclear Information System (INIS)

    Nalla, Venkatram; Ji Wei; Polavarapu, Lakshminarayana; Manga, Kiran Kumar; Goh, Bee Min; Loh, Kian Ping; Xu Qinghua

    2010-01-01

    A water soluble conjugated thiophene polymer, sodium salt of poly[2-(3-thienyl)ethoxy-4-butylsulfonate] (TPP), and graphene oxide (GO) composite film (GO-TPP) device was prepared. Transient photoconductivity measurements were carried out on the GO-TPP composite film using 150 ns laser pulses of 527 nm wavelength. Highly efficient photocurrent generation was observed from the GO-TPP film. The relationships of the film photoconductivity, photocurrent decay time and electron decay times with the incident light intensity were investigated. The photoconductive gain of the film was determined to be greater than 40% and to be independent of the light intensity. Furthermore, the femtosecond nonlinear optical properties of the GO-TPP film were measured using 800 nm femtosecond laser pulses and the composite film exhibited high nonlinear absorption and nonlinear refraction coefficients.

  19. Controlling morphology and chain aggregation in semiconducting conjugated polymers: the role of solvent on optical gain in MEH-PPV.

    Science.gov (United States)

    Lampert, Zach E; Reynolds, C Lewis; Papanikolas, John M; Aboelfotoh, M Osama

    2012-10-25

    We report the results of a detailed investigation that addresses the influence of polymer morphology and chain aggregation, as controlled by the chemical nature of the solvent, on the optical gain properties of the conjugated polymer poly[2-methoxy-5-(2'-ethylhexyloxy)-p-phenylene vinylene] (MEH-PPV). Using the variable stripe length technique in the picosecond regime, we have extensively studied the optical gain performance of asymmetric planar waveguides formed with thin MEH-PPV films spin-cast from concentrated chlorobenzene (CB) and tetrahydrofuran (THF) solutions onto thermally oxidized silicon substrates. CB and THF solvents were chosen based on their known ability to promote and effectively limit aggregate formation, respectively. Very large net gain coefficients are demonstrated, reaching values of 330 and 365 cm(-1), respectively, when optically pumping the waveguides with a maximum energy density of 85 μJ/cm(2). Our results clearly demonstrate that polymer morphology, and hence, the chain conformation dependence of the degree of aggregation in the films as controlled by the solvent, has minimal impact on the net gain. Moreover, the waveguides exhibit low loss coefficients of 10-20 cm(-1) at the ASE wavelength. These results question the importance of polymer morphology and aggregate formation in polymer-based optical devices operating at high excitation densities in the stimulated emission regime as would be characteristic of lasers and optical amplifiers.

  20. Self-Assembly and Crystallization of Conjugated Block Copolymers

    Science.gov (United States)

    Davidson, Emily Catherine

    This dissertation demonstrates the utility of molecular design in conjugated polymers to create diblock copolymers that robustly self-assemble in the melt and confine crystallization upon cooling. This work leverages the model conjugated polymer poly(3-(2'-ethyl)hexylthiophene) (P3EHT), which features a branched side chain, resulting in a dramatically reduced melting temperature (Tm 80°C) relative to the widely-studied poly(3-hexylthiophene) (P3HT) (Tm 200°C). This reduced melting temperature permits an accessible melt phase, without requiring that the segregation strength (chiN) be dramatically increased. Thus, diblock copolymers containing P3EHT demonstrate robust diblock copolymer self-assembly in the melt over a range of compositions and morphologies. Furthermore, confined crystallization in the case of both glassy (polystyrene (PS) matrix block) and soft (polymethylacrylate (PMA) matrix block) confinement is studied, with the finding that even in soft confinement, crystallization is constrained within the diblock microdomains. This success demonstrates the strategy of leveraging molecular design to decrease the driving force for crystallization as a means to achieving robust self-assembly and confined crystallization in conjugated block copolymers. Importantly, despite the relatively flexible nature of P3EHT in the melt, the diblock copolymer phase behavior appears to be significantly impacted by the stiffness (persistence length of 3 nm) of the P3EHT chain compared to the coupled amorphous blocks (persistence length 0.7 nm). In particular, it is shown that the synthesized morphologies are dominated by a very large composition window for lamellar geometries (favored at high P3EHT volume fractions); cylindrical geometries are favored when P3EHT is the minority fraction. This asymmetry of the composition window is attributed to impact of conformational asymmetry (the difference in chain stiffness, as opposed to shape) between conjugated and amorphous blocks

  1. Polymers targeting habitual diseases

    Science.gov (United States)

    The use of polymeric drug conjugates mainly for the treatment for cancer therapy has been addressed, but these polymers also find their way in treatment of various lifestyle disorders like diabetes, hypertension, cardiovascular diseases etc. The focus is being laid to develop biodegradable polymer ...

  2. Optical polymers for laser medical applications

    Science.gov (United States)

    Sultanova, Nina G.; Kasarova, Stefka N.; Nikolov, Ivan D.

    2016-01-01

    In medicine, optical polymers are used not only in ophthalmology but in many laser surgical, diagnostic and therapeutic systems. The application in lens design is determined by their refractive and dispersive properties in the considered spectral region. We have used different measuring techniques to obtain precise refractometric data in the visible and near-infrared spectral regions. Dispersive, thermal and other important optical characteristics of polymers have been studied. Design of a plastic achromatic objective, used in a surgical stereo-microscope at 1064 nm laser wavelength, is accomplished. Geometrical and wavefront aberrations are calculated. Another example of application of polymers is the designed all-mirror apochromatic micro-lens, intended for superluminescent diode fiber coupling in medical systems.

  3. Method to create gradient index in a polymer

    Science.gov (United States)

    Dirk, Shawn M; Johnson, Ross Stefan; Boye, Robert; Descour, Michael R; Sweatt, William C; Wheeler, David R; Kaehr, Bryan James

    2014-10-14

    Novel photo-writable and thermally switchable polymeric materials exhibit a refractive index change of .DELTA.n.gtoreq.1.0 when exposed to UV light or heat. For example, lithography can be used to convert a non-conjugated precursor polymer to a conjugated polymer having a higher index-of-refraction. Further, two-photon lithography can be used to pattern high-spatial frequency structures.

  4. Fluorescence polarization measures energy funneling in single light-harvesting antennas—LH2 vs conjugated polymers

    Science.gov (United States)

    Camacho, Rafael; Tubasum, Sumera; Southall, June; Cogdell, Richard J.; Sforazzini, Giuseppe; Anderson, Harry L.; Pullerits, Tõnu; Scheblykin, Ivan G.

    2015-10-01

    Numerous approaches have been proposed to mimic natural photosynthesis using artificial antenna systems, such as conjugated polymers (CPs), dendrimers, and J-aggregates. As a result, there is a need to characterize and compare the excitation energy transfer (EET) properties of various natural and artificial antennas. Here we experimentally show that EET in single antennas can be characterized by 2D polarization imaging using the single funnel approximation. This methodology addresses the ability of an individual antenna to transfer its absorbed energy towards a single pool of emissive states, using a single parameter called energy funneling efficiency (ɛ). We studied individual peripheral antennas of purple bacteria (LH2) and single CP chains of 20 nm length. As expected from a perfect antenna, LH2s showed funneling efficiencies close to unity. In contrast, CPs showed lower average funneling efficiencies, greatly varying from molecule to molecule. Cyclodextrin insulation of the conjugated backbone improves EET, increasing the fraction of CPs possessing ɛ = 1. Comparison between LH2s and CPs shows the importance of the protection systems and the protein scaffold of LH2, which keep the chromophores in functional form and at such geometrical arrangement that ensures excellent EET.

  5. Driving High-Performance n- and p-type Organic Transistors with Carbon Nanotube/Conjugated Polymer Composite Electrodes Patterned Directly from Solution

    KAUST Repository

    Hellstrom, Sondra L.

    2010-07-12

    We report patterned deposition of carbon nanotube/conjugated polymer composites from solution with high nanotube densities and excellent feature resolution. Such composites are suited for use as electrodes in high-performance transistors of pentacene and C60, with bottom-contact mobilities of ?0.5 and ?1 cm2 V-1 s-1, respectively. This represents a clear step towards development of inexpensive, high-performance all-organic circuits. © 2010 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Enhancement in fluorescence quantum yield of MEH-PPV:BT blends for polymer light emitting diode applications

    Science.gov (United States)

    Nimith, K. M.; Satyanarayan, M. N.; Umesh, G.

    2018-06-01

    We have investigated the effect of blending electron deficient heterocycle Benzothiadiazole (BT) on the photo-physical properties of conjugated polymer Poly [2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV). Quantum yield (QY) value has been found to increase from 37% for pure MEH-PPV to 45% for an optimum MEH-PPV:BT blend ratio of 1:3. This can be attributed to the efficient energy transfer from the wide bandgap BT (host) to the small bandgap MEH-PPV (guest). The FTIR spectrum of MEH-PPV:BT blended thin film indicates suppression of aromatic C-H out-of-plane and in-plane bending, suggesting planarization of the conjugated polymer chains and, hence, leading to increase in the conjugation length. The increase in conjugation length is also evident from the red-shifted PL spectra of MEH-PPV:BT blended films. Single layer MEH-PPV:BT device shows lower turn-on voltage than single layer MEH-PPV alone device. Further, the effect of electrical conductivity of PEDOT:PSS on the current-voltage characteristics is investigated in the PLED devices with MEH-PPV:BT blend as the active layer. PEDOT:PSS with higher conductivity as HIL reduces the turn on voltage from 4.5 V to 3.9 V and enhances the current density and optical output in the device.

  7. Structure-Property Relationships of Semiconducting Polymers for Flexible and Durable Polymer Field-Effect Transistors.

    Science.gov (United States)

    Kim, Min Je; Jung, A-Ra; Lee, Myeongjae; Kim, Dongjin; Ro, Suhee; Jin, Seon-Mi; Nguyen, Hieu Dinh; Yang, Jeehye; Lee, Kyung-Koo; Lee, Eunji; Kang, Moon Sung; Kim, Hyunjung; Choi, Jong-Ho; Kim, BongSoo; Cho, Jeong Ho

    2017-11-22

    We report high-performance top-gate bottom-contact flexible polymer field-effect transistors (FETs) fabricated by flow-coating diketopyrrolopyrrole (DPP)-based and naphthalene diimide (NDI)-based polymers (P(DPP2DT-T2), P(DPP2DT-TT), P(DPP2DT-DTT), P(NDI2OD-T2), P(NDI2OD-F2T2), and P(NDI2OD-Se2)) as semiconducting channel materials. All of the polymers displayed good FET characteristics with on/off current ratios exceeding 10 7 . The highest hole mobility of 1.51 cm 2 V -1 s -1 and the highest electron mobility of 0.85 cm 2 V -1 s -1 were obtained from the P(DPP2DT-T2) and P(NDI2OD-Se2) polymer FETs, respectively. The impacts of the polymer structures on the FET performance are well-explained by the interplay between the crystallinity, the tendency of the polymer backbone to adopt an edge-on orientation, and the interconnectivity of polymer fibrils in the film state. Additionally, we demonstrated that all of the flexible polymer-based FETs were highly resistant to tensile stress, with negligible changes in their carrier mobilities and on/off ratios after a bending test. Conclusively, these high-performance, flexible, and durable FETs demonstrate the potential of semiconducting conjugated polymers for use in flexible electronic applications.

  8. Synthesis, characterization and the release kinetics of antiproliferative agents from polyamidoamine conjugates

    CSIR Research Space (South Africa)

    Aderibigbe, BA

    2015-01-01

    Full Text Available Polyamidoamine conjugates containing curcumin and bisphosphonate were synthesized via a one-pot aqueous phase Michael addition reaction. In the design of the conjugate, bisphosphonate formed an integral part of the polymer carrier backbone. Curcumin...

  9. Synthesis of conjugated chitosan and its effect on drug permeation from transdermal patches.

    Science.gov (United States)

    Satheeshababu, B K; Shivakumar, K L

    2013-03-01

    The aim of this study was to synthesis the conjugated chitosan by covalent attachment of thiol moieties to the cationic polymer, mediated by a carbodiimide to improve permeation properties of chitosan. Thioglycolic acid was covalently attached to chitosan by the formation of amide bonds between the primary amino groups of the polymer and the carboxylic acid groups of thioglycolic acid. Hence, these polymers are called as thiomers or thiolated polymers. Conjugation of chitosan was confirmed by Fourier transform-infrared and differential scanning calorimetric analysis. Matrix type transdermal patches of carvedilol were prepared using the different proportions of chitosan and chitosan-thioglycolic acid conjugates (2:0, 1.7:0.3, 1.4:0.6, 1:1, 0.6:1.4 and 0.3:1.7) by solvent casting technique. Prepared matrix type patches were evaluated for their physicochemical characterization followed by in vitro evaluation. Selected formulations were subjected for their ex vivo studies on Wistar albino rat skin and human cadaver skin using the modified Franz diffusion cell. As the proportion of conjugated chitosan increased, the transdermal patches showed increased drug permeation. The mechanism of drug release was found to be nonFickian profiles. The present study concludes that the transdermal patches of carvedilol using conjugated chitosan with different proportions of chitosan were successfully developed to provide improved drug permeation. The transdermal patches can be a good approach to improve drug bioavailability by bypassing the extensive hepatic first-pass metabolism of the drug.

  10. Polymer and ceramic nanocomposites for aerospace applications

    Science.gov (United States)

    Rathod, Vivek T.; Kumar, Jayanth S.; Jain, Anjana

    2017-11-01

    This paper reviews the potential of polymer and ceramic matrix composites for aerospace/space vehicle applications. Special, unique and multifunctional properties arising due to the dispersion of nanoparticles in ceramic and metal matrix are briefly discussed followed by a classification of resulting aerospace applications. The paper presents polymer matrix composites comprising majority of aerospace applications in structures, coating, tribology, structural health monitoring, electromagnetic shielding and shape memory applications. The capabilities of the ceramic matrix nanocomposites to providing the electromagnetic shielding for aircrafts and better tribological properties to suit space environments are discussed. Structural health monitoring capability of ceramic matrix nanocomposite is also discussed. The properties of resulting nanocomposite material with its disadvantages like cost and processing difficulties are discussed. The paper concludes after the discussion of the possible future perspectives and challenges in implementation and further development of polymer and ceramic nanocomposite materials.

  11. Developing new methods for the mono-end functionalization of living ring opening metathesis polymers.

    Science.gov (United States)

    Kilbinger, Andreas F M

    2012-01-01

    In this article we present a review of our recent results in one area of research we are involved in. All research efforts in our group focus on functional polymers and new ways of gaining higher levels of control with regard to the placement of functional groups within these polymers. Here, the living ring opening metathesis polymerization (ROMP) will be reviewed for which end-functionalization methods had been rare until very recently. Polymers carrying particular functional groups only at the chain-ends are, however, very interesting for a variety of industrial and academic applications. Polymeric surfactants and polymer-protein conjugates are two examples for the former and polymer-β-sheet-peptide conjugates one example for the latter. The functionalization of macroscopic or nanoscopic surfaces often relies on mono-end functional polymers. Complex macromolecular architectures are often constructed from macromolecules carrying exactly one functional group at their chain- end. The ring opening metathesis polymerization is particularly interesting in this context as it is one of the most functional group tolerant polymerization methods known. Additionally, high molecular weight polymers are readily accessible with this technique, a feature that living radical polymerizations often struggle to achieve. Finding new ways of functionalizing the polymer chain-end of ROMP polymers has therefore been a task long overdue. Here, we present our contribution to this area of research.

  12. White light generation tuned by dual hybridization of nanocrystals and conjugated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Demir, Hilmi Volkan [Devices and Sensors Group and Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Nizamoglu, Sedat [Devices and Sensors Group and Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Ozel, Tuncay [Devices and Sensors Group and Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Mutlugun, Evren [Devices and Sensors Group and Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Huyal, Ilkem Ozge [Devices and Sensors Group and Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Sari, Emre [Devices and Sensors Group and Nanotechnology Research Center, Bilkent University, Ankara 06800 (Turkey); Holder, Elisabeth [Functional Polymers Group and Institute of Polymer Technology, University of Wuppertal, Gaussstrasse 20, D-42097 Wuppertal (Germany); Tian Nan [Functional Polymers Group and Institute of Polymer Technology, University of Wuppertal, Gaussstrasse 20, D-42097 Wuppertal (Germany)

    2007-10-15

    Dual hybridization of highly fluorescent conjugated polymers and highly luminescent nanocrystals (NCs) is developed and demonstrated in multiple combinations for controlled white light generation with high color rendering index (CRI) (> 80) for the first time. The generated white light is tuned using layer-by-layer assembly of CdSe/ZnS core-shell NCs closely packed on polyfluorene, hybridized on near-UV emitting nitride-based light emitting diodes (LEDs). The design, synthesis, growth, fabrication and characterization of these hybrid inorganic-organic white LEDs are presented. The following experimental realizations are reported: (i) layer-by-layer hybridization of yellow NCs ({lambda}{sub PL}=580 nm) and blue polyfluorene ({lambda}{sub PL}=439 nm) with tristimulus coordinates of (x, y)=(0.31, 0.27), correlated color temperature of T{sub c}=6962 K and CRI of R{sub a}=53.4; (ii) layer-by-layer assembly of yellow and green NCs ({lambda}{sub PL}=580 and 540 nm) and blue polyfluorene ({lambda}{sub PL}=439 nm) with (x, y)=(0.23, 0.30), T{sub c}=14395 K and R{sub a}=65.7; and (iii) layer-by-layer deposition of yellow, green and red NCs ({lambda}{sub PL}=580, 540 and 620 nm) and blue polyfluorene ({lambda}{sub PL}=439 nm) with (x, y)=(0.38, 0.39), T{sub c}=4052 K and R{sub a}= 83.0. The CRI is demonstrated to be well controlled and significantly improved by increasing multi-chromaticity of the NC and polymer emitters.

  13. pi-Conjugated polymers for photovoltaics

    NARCIS (Netherlands)

    Zoombelt, A.P.

    2009-01-01

    Polymer solar cells employ a nanoscopic phase separation or bulk heterojunction (BHJ) between two complementary molecular based p and n-type organic semiconductors to convert sunlight directly into electricity. The operational principle involves a complex sequence of events, starting with the

  14. Surface Modification of Polymer Substrates for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Oldřich Neděla

    2017-09-01

    Full Text Available While polymers are widely utilized materials in the biomedical industry, they are rarely used in an unmodified state. Some kind of a surface treatment is often necessary to achieve properties suitable for specific applications. There are multiple methods of surface treatment, each with their own pros and cons, such as plasma and laser treatment, UV lamp modification, etching, grafting, metallization, ion sputtering and others. An appropriate treatment can change the physico-chemical properties of the surface of a polymer in a way that makes it attractive for a variety of biological compounds, or, on the contrary, makes the polymer exhibit antibacterial or cytotoxic properties, thus making the polymer usable in a variety of biomedical applications. This review examines four popular methods of polymer surface modification: laser treatment, ion implantation, plasma treatment and nanoparticle grafting. Surface treatment-induced changes of the physico-chemical properties, morphology, chemical composition and biocompatibility of a variety of polymer substrates are studied. Relevant biological methods are used to determine the influence of various surface treatments and grafting processes on the biocompatibility of the new surfaces—mammalian cell adhesion and proliferation is studied as well as other potential applications of the surface-treated polymer substrates in the biomedical industry.

  15. Fused thiophene-based conjugated polymers and their use in optoelectronic devices

    Science.gov (United States)

    Facchetti, Antonio; Marks, Tobin J.; Takai, Atsuro; Seger, Mark; Chen; , Zhihua

    2017-07-18

    The present teachings relate to polymeric compounds and their use as organic semiconductors in organic and hybrid optical, optoelectronic, and/or electronic devices such as photovoltaic cells, light emitting diodes, light emitting transistors, and field effect transistors. The disclosed compounds generally include as repeating units at least one annulated thienyl-vinylene-thienyl (TVT) unit and at least one other pi-conjugated unit. The annulated TVT unit can be represented by the formula: ##STR00001## where Cy.sup.1 and Cy.sup.2 can be a five- or six-membered carbocyclic ring. The annulated TVT unit can be optionally substituted at any available ring atom(s), and can be covalently linked to the other pi-conjugated unit via either the thiophene rings or the carbocyclic rings Cy.sup.1 and Cy.sup.2. The other pi-conjugated unit can be a conjugated linear linker including one or more unsaturated bonds, or a conjugated cyclic linker including one or more carbocyclic and/or heterocyclic rings.

  16. Correlation of Disorder and Charge Transport in a Range of Indacenodithiophene-Based Semiconducting Polymers

    KAUST Repository

    Nikolka, Mark; Hurhangee, Michael; Sadhanala, Aditya; Chen, Hu; McCulloch, Iain; Sirringhaus, Henning

    2017-01-01

    uniformity paired with high charge carrier mobilities, conjugated polymers have attracted increasing attention in this respect. However, the performances delivered by current generation conjugated polymers still fall short of many industrial requirements

  17. Sugar-based amphiphilic polymers for biomedical applications: from nanocarriers to therapeutics.

    Science.gov (United States)

    Gu, Li; Faig, Allison; Abdelhamid, Dalia; Uhrich, Kathryn

    2014-10-21

    Various therapeutics exhibit unfavorable physicochemical properties or stability issues that reduce their in vivo efficacy. Therefore, carriers able to overcome such challenges and deliver therapeutics to specific in vivo target sites are critically needed. For instance, anticancer drugs are hydrophobic and require carriers to solubilize them in aqueous environments, and gene-based therapies (e.g., siRNA or pDNA) require carriers to protect the anionic genes from enzymatic degradation during systemic circulation. Polymeric micelles, which are self-assemblies of amphiphilic polymers (APs), constitute one delivery vehicle class that has been investigated for many biomedical applications. Having a hydrophobic core and a hydrophilic shell, polymeric micelles have been used as drug carriers. While traditional APs are typically comprised of nondegradable block copolymers, sugar-based amphiphilic polymers (SBAPs) synthesized by us are comprised of branched, sugar-based hydrophobic segments and a hydrophilic poly(ethylene glycol) chain. Similar to many amphiphilic polymers, SBAPs self-assemble into polymeric micelles. These nanoscale micelles have extremely low critical micelle concentrations offering stability against dilution, which occurs with systemic administration. In this Account, we illustrate applications of SBAPs for anticancer drug delivery via physical encapsulation within SBAP micelles and chemical conjugation to form SBAP prodrugs capable of micellization. Additionally, we show that SBAPs are excellent at stabilizing liposomal delivery systems. These SBAP-lipid complexes were developed to deliver hydrophobic anticancer therapeutics, achieving preferential uptake in cancer cells over normal cells. Furthermore, these complexes can be designed to electrostatically complex with gene therapies capable of transfection. Aside from serving as a nanocarrier, SBAPs have also demonstrated unique bioactivity in managing atherosclerosis, a major cause of cardiovascular

  18. Impact of charge carrier injection on single-chain photophysics of conjugated polymers

    Energy Technology Data Exchange (ETDEWEB)

    Hofmann, Felix J.; Vogelsang, Jan, E-mail: jan.vogelsang@physik.uni-regensburg.de; Lupton, John M. [Institut für Experimentelle und Angewandte Physik, Universität Regensburg, Universitätsstrasse 31, 93053 Regensburg (Germany)

    2016-06-27

    Charges in conjugated polymer materials have a strong impact on the photophysics and their interaction with the primary excited state species has to be taken into account in understanding device properties. Here, we employ single-molecule spectroscopy to unravel the influence of charges on several photoluminescence (PL) observables. The charges are injected either stochastically by a photochemical process or deterministically in a hole-injection sandwich device configuration. We find that upon charge injection, besides a blue-shift of the PL emission and a shortening of the PL lifetime due to quenching and blocking of the lowest-energy chromophores, the non-classical photon arrival time distribution of the multichromophoric chain is modified towards a more classical distribution. Surprisingly, the fidelity of photon antibunching deteriorates upon charging, whereas one would actually expect the opposite: the number of chromophores to be reduced. A qualitative model is presented to explain the observed PL changes. The results are of interest to developing a microscopic understanding of the intrinsic charge-exciton quenching interaction in devices.

  19. Smart conjugated polymer nanocarrier for healthy weight loss by negative feedback regulation of lipase activity

    Science.gov (United States)

    Chen, Yu-Lei; Zhu, Sha; Zhang, Lei; Feng, Pei-Jian; Yao, Xi-Kuang; Qian, Cheng-Gen; Zhang, Can; Jiang, Xi-Qun; Shen, Qun-Dong

    2016-02-01

    Healthy weight loss represents a real challenge when obesity is increasing in prevalence. Herein, we report a conjugated polymer nanocarrier for smart deactivation of lipase and thus balancing calorie intake. After oral administration, the nanocarrier is sensitive to lipase in the digestive tract and releases orlistat, which deactivates the enzyme and inhibits fat digestion. It also creates negative feedback to control the release of itself. The nanocarrier smartly regulates activity of the lipase cyclically varied between high and low levels. In spite of high fat diet intervention, obese mice receiving a single dose of the nanocarrier lose weight over eight days, whereas a control group continues the tendency to gain weight. Daily intragastric administration of the nanocarrier leads to lower weight of livers or fat pads, smaller adipocyte size, and lower total cholesterol level than that of the control group. Near-infrared fluorescence of the nanocarrier reveals its biodistribution.Healthy weight loss represents a real challenge when obesity is increasing in prevalence. Herein, we report a conjugated polymer nanocarrier for smart deactivation of lipase and thus balancing calorie intake. After oral administration, the nanocarrier is sensitive to lipase in the digestive tract and releases orlistat, which deactivates the enzyme and inhibits fat digestion. It also creates negative feedback to control the release of itself. The nanocarrier smartly regulates activity of the lipase cyclically varied between high and low levels. In spite of high fat diet intervention, obese mice receiving a single dose of the nanocarrier lose weight over eight days, whereas a control group continues the tendency to gain weight. Daily intragastric administration of the nanocarrier leads to lower weight of livers or fat pads, smaller adipocyte size, and lower total cholesterol level than that of the control group. Near-infrared fluorescence of the nanocarrier reveals its biodistribution

  20. Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications.

    Science.gov (United States)

    Viswanathan, Vinila N; Rao, Arun D; Pandey, Upendra K; Kesavan, Arul Varman; Ramamurthy, Praveen C

    2017-01-01

    A series of low band gap, planar conjugated polymers, P1 (PFDTBT), P2 (PFDTDFBT) and P3 (PFDTTBT), based on fluorene and benzothiadiazole, was synthesized. The effect of fluorine substitution and fused aromatic spacers on the optoelectronic and photovoltaic performance was studied. The polymer, derived from dithienylated benzothiodiazole and fluorene, P1 , exhibited a highest occupied molecular orbital (HOMO) energy level at -5.48 eV. Density functional theory (DFT) studies as well as experimental measurements suggested that upon substitution of the acceptor with fluorine, both the HOMO and lowest unoccupied molecular orbital (LUMO) energy levels of the resulting polymer, P2 , were lowered, leading to a higher open circuit voltage and short circuit current with an overall improvement of more than 110% for the photovoltaic devices. Moreover, a decrease in the torsion angle between the units was also observed for the fluorinated polymer P2 due to the enhanced electrostatic interaction between the fluorine substituents and sulfur atoms, leading to a high hole mobility. The use of a fused π-bridge in polymer P3 for the enhancement of the planarity as compared to the P1 backbone was also studied. This enhanced planarity led to the highest observed mobility among the reported three polymers as well as to an improvement in the device efficiency by more than 40% for P3 .

  1. Molecular-level architectural design using benzothiadiazole-based polymers for photovoltaic applications

    Science.gov (United States)

    Viswanathan, Vinila N; Rao, Arun D; Pandey, Upendra K; Kesavan, Arul Varman

    2017-01-01

    A series of low band gap, planar conjugated polymers, P1 (PFDTBT), P2 (PFDTDFBT) and P3 (PFDTTBT), based on fluorene and benzothiadiazole, was synthesized. The effect of fluorine substitution and fused aromatic spacers on the optoelectronic and photovoltaic performance was studied. The polymer, derived from dithienylated benzothiodiazole and fluorene, P1, exhibited a highest occupied molecular orbital (HOMO) energy level at −5.48 eV. Density functional theory (DFT) studies as well as experimental measurements suggested that upon substitution of the acceptor with fluorine, both the HOMO and lowest unoccupied molecular orbital (LUMO) energy levels of the resulting polymer, P2, were lowered, leading to a higher open circuit voltage and short circuit current with an overall improvement of more than 110% for the photovoltaic devices. Moreover, a decrease in the torsion angle between the units was also observed for the fluorinated polymer P2 due to the enhanced electrostatic interaction between the fluorine substituents and sulfur atoms, leading to a high hole mobility. The use of a fused π-bridge in polymer P3 for the enhancement of the planarity as compared to the P1 backbone was also studied. This enhanced planarity led to the highest observed mobility among the reported three polymers as well as to an improvement in the device efficiency by more than 40% for P3. PMID:28546844

  2. Indication of critical micelle concentration of nonionic surfactants with large emission change using water-soluble conjugated polymer as molecular light switch

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Lilin, E-mail: sunlilin126@126.com [Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Hao, Dan; Zhang, Ping; Qian, Zhangsheng; Shen, Weili [Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Shao, Taili [Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China); Department of Pharmacy, Wannan Medical College, Wuhu 241000 (China); Zhu, Changqing, E-mail: zhucq@mail.ahnu.edu.cn [Anhui Key Laboratory of Chemo-Biosensing, College of Chemistry and Materials Science, Anhui Normal University, Wuhu 241000 (China)

    2013-02-15

    A new near-infrared water-soluble conjugated polymer, i.e. poly [2,5-di (propyloxysulfonate)-1,4-phenylene-ethynylene-9,10-anthrylene] (PPEASO3) was synthesized to investigate its interaction with surfactants. It was found that PPEASO3 has only a weak fluorescence emission at about 670 nm due to its self-aggregation in water and in aqueous solution containing a low concentration of nonionic surfactants, i.e. below their critical micelle concentration (CMC). However, a dramatic fluorescence enhancement with a large emission blue-shift (>40 nm) was found once the concentration of nonionic surfactants reached the CMC (especially for Triton X-100). An orange fluorescence could be observed even with naked-eyes under UV-lamp, which gave a direct indication for the micelle forming process and provided a simple method for the CMC determination of the nonionic surfactants. The CMC values determined by this method were in good agreement with those obtained by other techniques. The dramatic emission change observed could be ascribed to the intensive hydrophobic interaction between PPEASO3 and surfactants micelle, which greatly disrupts the aggregation of the polymer and increase the fluorescence efficiency of PPEASO3. Highlights: Black-Right-Pointing-Pointer Investigated the interaction of a new water-soluble conjugated polymer with surfactants. Black-Right-Pointing-Pointer The dramatic fluorescence enhancement and emission blue-shift were observed at the CMC. Black-Right-Pointing-Pointer The obvious emission color change could be observed with naked-eyes under UV-lamp. Black-Right-Pointing-Pointer Gave a direct indication for the micelle forming process. Black-Right-Pointing-Pointer Provided a simple method for the CMC determination of the nonionic surfactants.

  3. Production and Application of Lysozyme-Gum Arabic Conjugate in Mayonnaise as a Natural Preservative and Emulsifier

    DEFF Research Database (Denmark)

    Hashemi, Marjan M.; Aminlari, Mahmoud; Forouzan, Mehdi M.

    2018-01-01

    Nowadays demand for food products made by natural sources is rising so fast. In this work Lysozyme (Lyz) was conjugated with gum Arabic (GA) in order to be applied in mayonnaise, at which the presence of both preservative and emulsifier is essential. Interestingly, the Lyz-GA conjugate exhibited...... possible the application of a natural preservative and emulsifier in food and pharmaceutical industries, whereas Lyz alone does not have a broad-spectrum antibacterial activity or emulsifying properties....... improved functional properties and antibacterial activity. In order to approve the results of this study, the Lyz-GA conjugate was applied to mayonnaise as a natural preservative and emulsifier. Application of the Lzy-GA conjugate in mayonnaise expedited the death rate of both S. aureus and E. coli K-12...

  4. Online size-exclusion high-performance liquid chromatography light scattering and differential refractometry methods to determine degree of polymer conjugation to proteins and protein-protein or protein-ligand association states.

    Science.gov (United States)

    Kendrick, B S; Kerwin, B A; Chang, B S; Philo, J S

    2001-12-15

    Characterizing the solution structure of protein-polymer conjugates and protein-ligand interactions is important in fields such as biotechnology and biochemistry. Size-exclusion high-performance liquid chromatography with online classical light scattering (LS), refractive index (RI), and UV detection offers a powerful tool in such characterization. Novel methods are presented utilizing LS, RI, and UV signals to rapidly determine the degree of conjugation and the molecular mass of the protein conjugate. Baseline resolution of the chromatographic peaks is not required; peaks need only be sufficiently separated to represent relatively pure fractions. An improved technique for determining the polypeptide-only mass of protein conjugates is also described. These techniques are applied to determining the degree of erythropoietin glycosylation, the degree of polyethylene glycol conjugation to RNase A and brain-derived neurotrophic factor, and the solution association states of these molecules. Calibration methods for the RI, UV, and LS detectors will also be addressed, as well as online methods to determine protein extinction coefficients and dn/dc values both unconjugated and conjugated protein molecules. (c)2001 Elsevier Science.

  5. Effect of temperature and ph on the drug release rate from a polymer conjugate system

    International Nuclear Information System (INIS)

    Kenawy, E.; Abdel-Hay, F.I.; El-Newehy, M.H.; Ottenbrite, R.M.

    2005-01-01

    Hydroximide and A-methylhydroxamic acid of poly(ethylene-altmaleic anhydride) (average MW 100-500 k) were used as a carrier for a new drug delivery system. The synthesis of the hydroximide and N methylhydroxamic acid of poly(ethylene-alt-maleic anhydride) were carried out by chemical modification of poly(ethylene-alt-maleic anhydride) with hydroxylamine and N-methyl hydroxylamine, respectively, in N,N- dimethylformamide at room temperature to yield water soluble copolymer. Ketoprofen was reacted with hydroximide and N-methylhydroxamic acid derivatives of poly(ethylene-alt-maleic anhydride) using dicyclohexylcarbodiimide as condensation agent at -5 degree C to yield water insoluble ketoprofen conjugates. All products were characterized by elemental analysis, FTIR and 1HNMR spectra. The in-vitro ketoprofen release was carried out by UV spectrophotometer at max =260 nm. The results demonstrated the effectiveness of hydroximide and N-methylhydroxamic acid of polyethylene-alt-maleic anhydride) as a drug delivery system. The release rates were studied at various ph and temperatures. The copolymer-drug adducts released the drug very slowly at the low ph found in the stomach thus protecting the drug from the action of high concentrations of digestive acids. These results showed the usefulness of hydroxamic acid polymer-drug conjugates as a new drug delivery system for drugs to be targeted to sites in the GI system

  6. Synthesis and organisation of poly-substituted porphyrins in thin films for the elaboration of a highly conjugated 2D polymer

    International Nuclear Information System (INIS)

    Da Cruz, Fernande

    1997-01-01

    This research thesis addresses the production and characterization of organic thin layers for the elaboration of a wholly conjugated bi-dimensional polymer. The author first reports the synthesis of molecules belonging to the substituted porphyrin family substituted by reactive functions (acetylenic and thiophene functions). He reports how these molecules are organised under the form of a plane paving by using the Langmuir-Blodgett (LB) technique and self-assembly. It has been possible to obtain steady and organised LB films from one the synthesized porphyrins. A new method of organisation based on self-assembly has been developed, and allowed polymerizable organised porphyrin single layers to be obtained. This opens a promising way to the production of the bi-dimensional polymer. Thin films have been characterized by UV-visible spectrophotometry, IR spectrometry, X-ray diffraction, and linear dichroism [fr

  7. Self-Assembled Nanocarriers Based on Amphiphilic Natural Polymers for Anti- Cancer Drug Delivery Applications.

    Science.gov (United States)

    Sabra, Sally; Abdelmoneem, Mona; Abdelwakil, Mahmoud; Mabrouk, Moustafa Taha; Anwar, Doaa; Mohamed, Rania; Khattab, Sherine; Bekhit, Adnan; Elkhodairy, Kadria; Freag, May; Elzoghby, Ahmed

    2017-01-01

    Micellization provides numerous merits for the delivery of water insoluble anti-cancer therapeutic agents including a nanosized 'core-shell' drug delivery system. Recently, hydrophobically-modified polysaccharides and proteins are attracting much attention as micelle forming polymers to entrap poorly soluble anti-cancer drugs. By virtue of their small size, the self-assembled micelles can passively target tumor tissues via enhanced permeation and retention effect (EPR). Moreover, the amphiphilic micelles can be exploited for active-targeted drug delivery by attaching specific targeting ligands to the outer micellar hydrophilic surface. Here, we review the conjugation techniques, drug loading methods, physicochemical characteristics of the most important amphiphilic polysaccharides and proteins used as anti-cancer drug delivery systems. Attention focuses on the mechanisms of tumor-targeting and enhanced anti-tumor efficacy of the encapsulated drugs. This review will highlight the remarkable advances of hydrophobized polysaccharide and protein micelles and their potential applications as anti-cancer drug delivery nanosystems. Micellar nanocarriers fabricated from amphiphilic natural polymers hold great promise as vehicles for anti-cancer drugs. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  8. Cellular delivery and antisense effects of peptide nucleic acid conjugated to polyethyleneimine via disulfide linkers

    DEFF Research Database (Denmark)

    Berthold, Peter R; Shiraishi, Takehiko; Nielsen, Peter E

    2010-01-01

    Peptide nucleic acid (PNA) is potentially an attractive antisense and antigene agent for which more efficient cellular delivery systems are still warranted. The cationic polymer polyethylenimine (PEI) is commonly used for cellular transfection of DNA and RNA complexes, but is not readily applicable...... moiety) and further reacted this with a cysteine PNA. The level of modification was determined spectrophotometrically with high accuracy, and the PNA transfection efficiency of the conjugates was evaluated in an antisense luciferase splice-correction assay using HeLa pLuc705 cells. We find that PEI...... is an efficient vector for PNA delivery yielding significantly higher (up to 10-fold) antisense activity than an analogous PNA-octaarginine conjugate, even in the presence of chloroquine, which only slightly enhances the PEI-PNA activity. The PEI-PEG conjugates are preferred due to lower acute cellular toxicity...

  9. Antibody-Conjugated Nanoparticles for Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Manuel Arruebo

    2009-01-01

    Full Text Available Nanoscience and Nanotechnology have found their way into the fields of Biotechnology and Medicine. Nanoparticles by themselves offer specific physicochemical properties that they do not exhibit in bulk form, where materials show constant physical properties regardless of size. Antibodies are nanosize biological products that are part of the specific immune system. In addition to their own properties as pathogens or toxin neutralizers, as well as in the recruitment of immune elements (complement, improving phagocytosis, cytotoxicity antibody dependent by natural killer cells, etc., they could carry several elements (toxins, drugs, fluorochroms, or even nanoparticles, etc. and be used in several diagnostic procedures, or even in therapy to destroy a specific target. The conjugation of antibodies to nanoparticles can generate a product that combines the properties of both. For example, they can combine the small size of nanoparticles and their special thermal, imaging, drug carrier, or magnetic characteristics with the abilities of antibodies, such as specific and selective recognition. The hybrid product will show versatility and specificity. In this review, we analyse both antibodies and nanoparticles, focusing especially on the recent developments for antibody-conjugated nanoparticles, offering the researcher an overview of the different applications and possibilities of these hybrid carriers.

  10. Conformational assembly and biological properties of collagen mimetic peptides and their thermally responsive polymer conjugates

    Science.gov (United States)

    Krishna, Ohm Divyam

    2011-12-01

    Collagens are one of the most abundant proteins found in body tissues and organs, endowing structural integrity, mechanical strength, and multiple biological functions. Destabilized collagen inside human body leads to various degenerative diseases (ex. osteoarthritis) and ageing. This has continued to motivate the design of synthetic peptides and bio-synthetic polypeptides to closely mimic the native collagens in terms of triple helix structure and stability, potential for higher order assembly, and biological properties. However, the widespread application of de novo collagens has been limited in part by the need for hydroxylated proline in the formation of stable triple helical structures. To address this continued need, a hydroxyproline-free, thermally stable collagen-mimetic peptide (CLP-Cys) was rationally designed via the incorporation of electrostatically stabilized amino acid triplets. CLP-Cys was synthesized via solid phase peptide synthesis. The formation and stability of the triple helical structure were indicated via circular dichroism (CD) experiments and confirmed via differential scanning calorimetry (DSC) results. CLP-Cys also self-assembled into nano-rods and micro-fibrils, as evidenced via a combination of dynamic light scattering and transmission electron microscopy. Given the high thermal stability and its propensity for higher-order assembly, CLP-Cys was further functionalized at both the ends with a thermally responsive polymer, poly(diethylene glycol methyl ether methacrylate), (PDEGMEMA) to synthesize a biohybrid triblock copolymer. The CD results indicated that the triple helical form is retained, the thermal unfolding is sustained and helix to coil transition is reversible in the triblock hybrid context. The LCST of PDEGMEMA homopolymer (26 °C) is increased (to 35 °C) upon conjugation to the hydrophilic collagen peptide domain. Further, a combination of static light scattering, Cryo-SEM, TEM and confocal microscopy elucidated that the

  11. AIE Polymers: Synthesis, Properties, and Biological Applications.

    Science.gov (United States)

    Zhan, Ruoyu; Pan, Yutong; Manghnani, Purnima Naresh; Liu, Bin

    2017-05-01

    Aggregation-caused quenching (ACQ) is a general phenomenon that is faced by traditional fluorescent polymers. Aggregation-induced emission (AIE) is exactly opposite to ACQ. AIE molecules are almost nonemissive in their molecularly dissolved state, but they can be induced to show high fluorescence in the aggregated or solid state. Incorporation of AIE phenomenon into polymer design has yielded various polymers with AIE characteristics. In this review, the recent progress of AIE polymers for biological applications is summarized. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Inorganic-whisker-reinforced polymer composites synthesis, properties and applications

    CERN Document Server

    Sun, Qiuju

    2015-01-01

    Inorganic-Whisker-Reinforced Polymer Composites: Synthesis, Properties and Applications gives a comprehensive presentation of inorganic microcrystalline fibers, or whiskers, a polymer composite filler. It covers whisker synthesis, surface modification, applications for reinforcing polymer-matrix composites, and analysis of resulting filled polymer composites. It focuses on calcium carbonate whiskers as a primary case study, introducing surface treatment methods for calcium carbonate whiskers and factors that influence them. Along with calcium carbonate, the book discusses potassium titanate and aluminum borate whiskers, which also comprise the new generation of inorganic whiskers. According to research results, composites filled by inorganic whiskers show improved strength, wear-resistance, thermal conductivity, and antistatic properties. It explains the importance of modifying polymer materials for use with inorganic whiskers and describes preparation and evaluation methods of polymers filled with inorganic ...

  13. Conjugated Polymer Chains Confined in Vertical Nanocylinders of a Block-Copolymer Film: Preparation, Characterization, and Optoelectronic Function

    KAUST Repository

    Dong, Ban Xuan; Honmou, Yoshihiro; Komiyama, Hideaki; Furumaki, Shu; Iyoda, Tomokazu; Vacha, Martin

    2013-01-01

    Hybrid materials composed of phase-separated block copolymer films and conjugated polymers of the phenylenevinylene family (PPV) are prepared. The PPV chains are embedded in vertical cylinders of nanometer diameter in the block-copolymer films. The cylinders span continuously the whole film thickness of 70 nm. Incorporation of the PPV chains into the one-dimensional cylinders leads to modified photoluminescence spectra and to large absorption anisotropy. The hybrid films show electroluminescence from the PPV chains in a simple light-emitting device at minute doping concentrations, and also exhibit a factor of 19 increase in electron transport efficiency along the single PPV chains. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Photonics of a conjugated organometallic Pt-Ir polymer and its model compounds exhibiting hybrid CT excited states.

    Science.gov (United States)

    Soliman, Ahmed M; Fortin, Daniel; Zysman-Colman, Eli; Harvey, Pierre D

    2012-04-13

    Trans- dichlorobis(tri-n-butylphosphine)platinum(II) reacts with bis(2- phenylpyridinato)-(5,5'-diethynyl-2,2'-bipyridine)iridium(III) hexafluorophosphate to form the luminescent conjugated polymer poly[trans-[(5,5'-ethynyl-2,2'-bipyridine)bis(2- phenylpyridinato)-iridium(III)]bis(tri-n-butylphosphine)platinum(II)] hexafluorophosphate ([Pt]-[Ir])n. Gel permeation chromatography indicates a degree of polymerization of 9 inferring the presence of an oligomer. Comparison of the absorption and emission band positions and their temperature dependence, emission quantum yields, and lifetimes with those for models containing only the [Pt] or the [Ir] units indicates hybrid excited states including features from both chromophores. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Conjugated Polymer Chains Confined in Vertical Nanocylinders of a Block-Copolymer Film: Preparation, Characterization, and Optoelectronic Function

    KAUST Repository

    Dong, Ban Xuan

    2013-01-15

    Hybrid materials composed of phase-separated block copolymer films and conjugated polymers of the phenylenevinylene family (PPV) are prepared. The PPV chains are embedded in vertical cylinders of nanometer diameter in the block-copolymer films. The cylinders span continuously the whole film thickness of 70 nm. Incorporation of the PPV chains into the one-dimensional cylinders leads to modified photoluminescence spectra and to large absorption anisotropy. The hybrid films show electroluminescence from the PPV chains in a simple light-emitting device at minute doping concentrations, and also exhibit a factor of 19 increase in electron transport efficiency along the single PPV chains. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. alpha-Glucosidase-albumin conjugates: effect of chronic administration in mice

    International Nuclear Information System (INIS)

    Allen, T.M.; Murray, L.; Bhardwaj, D.; Poznansky, M.J.

    1985-01-01

    Enzyme albumin conjugates have been proposed as a means of increasing the efficacy of enzyme use in vivo and decreasing immune response to the enzyme. Particulate drug carriers, however, have a pronounced tendency to localize in the mononuclear phagocyte (reticuloendothelial) system. The authors have examined in mice the effect on phagocytic index, tissue distribution and organ size of continued administration of conjugates of alpha-glucosidase with either homologous or heterologous albumin. Mice received 10 X 2-mg injections of bovine serum albumin (BSA) or mouse serum albumin (MSA), either free, polymerized or conjugated with alpha-glucosidase. Experiments involving BSA had to be terminated before the end of the experiment because of anaphylaxis, but these reactions were less severe to the polymerized albumin than to free albumin. Free BSA, BSA polymer and BSA-enzyme conjugates all caused a decrease in phagocytic index after six injections. Mice receiving MSA showed no evidence of anaphylaxis, but mice receiving six or more injections of free MSA, MSA polymer or MSA-enzyme conjugate had significantly decreased phagocytic indices as compared to controls. Phagocytic indices had returned to normal by 7 days after the final injection. Tissue distribution of 125 I-labeled albumin preparations was determined in either naive or chronically injected mice

  17. Energy Device Applications of Synthesized 1D Polymer Nanomaterials.

    Science.gov (United States)

    Huang, Long-Biao; Xu, Wei; Hao, Jianhua

    2017-11-01

    1D polymer nanomaterials as emerging materials, such as nanowires, nanotubes, and nanopillars, have attracted extensive attention in academia and industry. The distinctive, various, and tunable structures in the nanoscale of 1D polymer nanomaterials present nanointerfaces, high surface-to-volume ratio, and large surface area, which can improve the performance of energy devices. In this review, representative fabrication techniques of 1D polymer nanomaterials are summarized, including electrospinning, template-assisted, template-free, and inductively coupled plasma methods. The recent advancements of 1D polymer nanomaterials in energy device applications are demonstrated. Lastly, existing challenges and prospects of 1D polymer nanomaterials for energy device applications are presented. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Protein cages and synthetic polymers: a fruitful symbiosis for drug delivery applications, bionanotechnology and materials science.

    Science.gov (United States)

    Rother, Martin; Nussbaumer, Martin G; Renggli, Kasper; Bruns, Nico

    2016-11-07

    Protein cages are hollow protein nanoparticles, such as viral capsids, virus-like particles, ferritin, heat-shock proteins and chaperonins. They have well-defined capsule-like structures with a monodisperse size. Their protein subunits can be modified by genetic engineering at predetermined positions, allowing for example site-selective introduction of attachment points for functional groups, catalysts or targeting ligands on their outer surface, in their interior and between subunits. Therefore, protein cages have been extensively explored as functional entities in bionanotechnology, as drug-delivery or gene-delivery vehicles, as nanoreactors or as templates for the synthesis of organic and inorganic nanomaterials. The scope of functionalities and applications of protein cages can be significantly broadened if they are combined with synthetic polymers on their surface or within their interior. For example, PEGylation reduces the immunogenicity of protein cage-based delivery systems and active targeting ligands can be attached via polymer chains to favour their accumulation in diseased tissue. Polymers within protein cages offer the possibility of increasing the loading density of drug molecules, nucleic acids, magnetic resonance imaging contrast agents or catalysts. Moreover, the interaction of protein cages and polymers can be used to modulate the size and shape of some viral capsids to generate structures that do not occur with native viruses. Another possibility is to use the interior of polymer cages as a confined reaction space for polymerization reactions such as atom transfer radical polymerization or rhodium-catalysed polymerization of phenylacetylene. The protein nanoreactors facilitate a higher degree of control over polymer synthesis. This review will summarize the hybrid structures that have been synthesized by polymerizing from protein cage-bound initiators, by conjugating polymers to protein cages, by embedding protein cages into bulk polymeric

  19. Optically transparent semiconducting polymer nanonetwork for flexible and transparent electronics

    Science.gov (United States)

    Yu, Kilho; Park, Byoungwook; Kim, Geunjin; Kim, Chang-Hyun; Park, Sungjun; Kim, Jehan; Jung, Suhyun; Jeong, Soyeong; Kwon, Sooncheol; Kang, Hongkyu; Kim, Junghwan; Yoon, Myung-Han; Lee, Kwanghee

    2016-01-01

    Simultaneously achieving high optical transparency and excellent charge mobility in semiconducting polymers has presented a challenge for the application of these materials in future “flexible” and “transparent” electronics (FTEs). Here, by blending only a small amount (∼15 wt %) of a diketopyrrolopyrrole-based semiconducting polymer (DPP2T) into an inert polystyrene (PS) matrix, we introduce a polymer blend system that demonstrates both high field-effect transistor (FET) mobility and excellent optical transparency that approaches 100%. We discover that in a PS matrix, DPP2T forms a web-like, continuously connected nanonetwork that spreads throughout the thin film and provides highly efficient 2D charge pathways through extended intrachain conjugation. The remarkable physical properties achieved using our approach enable us to develop prototype high-performance FTE devices, including colorless all-polymer FET arrays and fully transparent FET-integrated polymer light-emitting diodes. PMID:27911774

  20. From Semi- to Full-Two-Dimensional Conjugated Side-Chain Design: A Way toward Comprehensive Solar Energy Absorption

    Energy Technology Data Exchange (ETDEWEB)

    Chao, Pengjie [Department; School; Wang, Huan [Department; Qu, Shiwei [Department; Mo, Daize [Department; Meng, Hong [School; Chen, Wei [Materials; Institute; He, Feng [Department

    2017-12-05

    Two polymers with fully two-dimensional (2D) conjugated side chains, 2D-PTB-Th and 2D-PTB-TTh, were synthesized and characterized through simultaneously integrating the 2D-TT and the 2D-BDT monomers onto the polymer backbone. Resulting from the synergistic effect from the conjugated side chains on both monomers, the two polymers showed remarkably efficient absorption of the sunlight and improved pi-pi intermolecular interactions for efficient charge carrier transport. The optimized bulk heterojunction device based on 2D-PTB-Th and PC71BM shows a higher PCE of 9.13% compared to PTB7-Th with a PCE of 8.26%, which corresponds to an approximately 10% improvement in solar energy conversion. The fully 2D-conjugated side-chain concept reported here developed a new molecular design strategy for polymer materials with enhanced sunlight absorption and efficient solar energy conversion.

  1. Biocompatible electrospun polymer blends for biomedical applications.

    Science.gov (United States)

    Munj, Hrishikesh Ramesh; Nelson, M Tyler; Karandikar, Prathamesh Sadanand; Lannutti, John Joseph; Tomasko, David Lane

    2014-10-01

    Blends of natural and synthetic polymers have received considerable attention as biomaterials due to the potential to optimize both mechanical and bioactive properties. Electrospinning of biocompatible polymers is an efficient method producing biomimetic topographies suited to various applications. In the ultimate application, electrospun scaffolds must also incorporate drug/protein delivery for effective cell growth and tissue repair. This study explored the suitability of a ternary Polymethylmethacrylate-Polycaprolactone-gelatin blend in the preparation of electrospun scaffolds for biomedical applications. Tuning the blend composition allows control over scaffold mechanical properties and degradation rate. Significant improvements were observed in the mechanical properties of the blend compared with the individual components. In order to study drug delivery potential, triblends were impregnated with the model compound Rhodamine-B using sub/supercritical CO₂ infusion under benign conditions. Results show significantly distinct release profiles of the impregnated dye from the triblends. Specific factors such as porosity, degradation rate, stress relaxation, dye-polymer interactions, play key roles in impregnation and release. Each polymer component of the triblends shows distinct behavior during impregnation and release process. This affects the aforementioned factors and the release profiles of the dye. Careful control over blend composition and infusion conditions creates the flexibility needed to produce biocompatible electrospun scaffolds for a variety of biomedical applications. © 2014 Wiley Periodicals, Inc.

  2. Recent Advances in Glycerol Polymers: Chemistry and Biomedical Applications

    Science.gov (United States)

    Zhang, Heng

    2015-01-01

    Glycerol polymers are attracting increased attention due to the diversity of polymer compositions and architectures available. This article provides a brief chronological review on the current status of these polymers along with representative examples of their use for biomedical applications. First, we describe the underlying chemistry of glycerol, which provides access to a range of monomers for subsequent polymerizations. We then review the various synthetic methodologies to prepare glycerol-based polymers including polyethers, polycarbonates, polyesters, and so forth. Next, we describe several biomedical applications where glycerol polymers are being investigated including carriers for drug delivery, sealants or coatings for tissue repair, and agents possessing antibacterial activity. Fourth, we describe the growing market opportunity for the use of polymers in medicine. Finally we conclude and summarize the findings, as well as discuss potential opportunities for continued research efforts. PMID:25308354

  3. Photoinduced electron transfer for an eosin-tyrosine conjugate. Activity of the tyrosinate anion in long-range electron transfer in a protein-like polymer matrix

    Energy Technology Data Exchange (ETDEWEB)

    Jones, G. II; Feng, Z.; Oh, C. [Boston Univ., MA (United States)

    1995-03-23

    The Xanthene dye eosin Y has been modified via a thiohydantoin link to the amine terminus of the amino acid L-tyrosine. Photochemical electron transfer involving the singlet state of the dye and the attached phenol-containing residue led to a reduction in eosin fluorescence quantum yield and lifetime for aqueous solutions at elevated pH. The conjugate provided an electron transfer product of relatively long lifetime (1 {mu}s range) observed by flash photolysis of solutions at pH 12.0, conditions under which the tyrosine moiety is ionized. The effects of binding of the conjugate in the polymer poly(vinylpyrrolidone) (PVP) on the rates of electron transfer of species of different charge type were examined. 30 refs., 5 figs., 1 tab.

  4. Applications of ionic liquids in polymer science and technology

    CERN Document Server

    2015-01-01

    This book summarizes the latest knowledge in the science and technology of ionic liquids and polymers in different areas. Ionic liquids (IL) are actively being investigated in polymer science and technology for a number of different applications. In the first part of the book the authors present the particular properties of ionic liquids as speciality solvents. The state-of-the art in the use of ionic liquids in polymer synthesis and modification reactions including polymer recycling is outlined. The second part focuses on the use of ionic liquids as speciality additives such as plasticizers or antistatic agents.  The third part examines the use of ionic liquids in the design of functional polymers (usually called polymeric ionic liquids (PIL) or poly(ionic liquids)). Many important applications in diverse scientific and industrial areas rely on these polymers, like polymer electrolytes in electrochemical devices, building blocks in materials science, nanocomposites, gas membranes, innovative anion sensitive...

  5. Properties and applications of polymer nanocomposites clay and carbon based polymer nanocomposites

    CERN Document Server

    Prasad Sahoo, Bibhu

    2017-01-01

    The aim of the present edited book is to furnish scientific information about manufacturing, properties, and application of clay and carbon based polymer nanocomposites. It can be used as handbook for undergraduate and post graduate courses (for example material science and engineering, polymer science and engineering, rubber technology, manufacturing engineering, etc.) as well as as reference book for research fellows and professionals. Polymer nanocomposites have received outstanding importance in the present decade because of their broad range of high-performance applications in various areas of engineering and technology due to their special material properties. A great interest is dedicated to nanofiller based polymeric materials, which exhibit excellent enhancement in macroscopic material properties (mechanical, thermal, dynamic mechanical, electrical and many more) at very low filler contents and can therefore be used for the development of next-generation composite materials.

  6. Peptide-mediated vectorization of metal complexes: conjugation strategies and biomedical applications.

    Science.gov (United States)

    Soler, Marta; Feliu, Lidia; Planas, Marta; Ribas, Xavi; Costas, Miquel

    2016-08-16

    The rich chemical and structural versatility of transition metal complexes provides numerous novel paths to be pursued in the design of molecules that exert particular chemical or physicochemical effects that could operate over specific biological targets. However, the poor cell permeability of metallodrugs represents an important barrier for their therapeutic use. The conjugation between metal complexes and a functional peptide vector can be regarded as a versatile and potential strategy to improve their bioavailability and accumulation inside cells, and the site selectivity of their effect. This perspective lies in reviewing the recent advances in the design of metallopeptide conjugates for biomedical applications. Additionally, we highlight the studies where this approach has been directed towards the incorporation of redox active metal centers into living organisms for modulating the cellular redox balance, as a tool with application in anticancer therapy.

  7. Electroluminescence of Multicomponent Conjugated Polymers. 1. Roles of Polymer/Polymer Interfaces in Emission Enhancement and Voltage-Tunable Multicolor Emission in Semiconducting Polymer/Polymer Heterojunctions

    National Research Council Canada - National Science Library

    Zhang, Xuejun, Ph.D

    1999-01-01

    Effects of the electronic structure of polymer/polymer interfaces on the electroluminescence efficiency and tunable multicolor emission of polymer heterojunction light-emitting diodes were explored...

  8. Polymer-Nanoparticle Composites: From Synthesis to Modern Applications

    Directory of Open Access Journals (Sweden)

    Thomas Hanemann

    2010-05-01

    Full Text Available The addition of inorganic spherical nanoparticles to polymers allows the modification of the polymers physical properties as well as the implementation of new features in the polymer matrix. This review article covers considerations on special features of inorganic nanoparticles, the most important synthesis methods for ceramic nanoparticles and nanocomposites, nanoparticle surface modification, and composite formation, including drawbacks. Classical nanocomposite properties, as thermomechanical, dielectric, conductive, magnetic, as well as optical properties, will be summarized. Finally, typical existing and potential applications will be shown with the focus on new and innovative applications, like in energy storage systems.

  9. Photoreconfigurable polymers for biomedical applications: chemistry and macromolecular engineering.

    Science.gov (United States)

    Zhu, Congcong; Ninh, Chi; Bettinger, Christopher J

    2014-10-13

    Stimuli-responsive polymers play an important role in many biomedical technologies. Light responsive polymers are particularly desirable because the parameters of irradiated light and diverse photoactive chemistries produce a large number of combinations between functional materials and associated stimuli. This Review summarizes recent advances in utilizing photoactive chemistries in macromolecules for prospective use in biomedical applications. Special focus is granted to selection criterion when choosing photofunctional groups. Synthetic strategies to incorporate these functionalities into polymers and networks with different topologies are also highlighted herein. Prospective applications of these materials are discussed including programmable matrices for controlled release, dynamic scaffolds for tissue engineering, and functional coatings for medical devices. The article concludes by summarizing the state of the art in photoresponsive polymers for biomedical applications including current challenges and future opportunities.

  10. Surface Modification of Carbon Nanotubes with Conjugated Polyelectrolytes: Fundamental Interactions and Applications in Composite Materials, Nanofibers, Electronics, and Photovoltaics

    KAUST Repository

    Ezzeddine, Alaa

    2015-10-01

    Ever since their discovery, Carbon nanotubes (CNTs) have been renowned to be potential candidates for a variety of applications. Nevertheless, the difficulties accompanied with their dispersion and poor solubility in various solvents have hindered CNTs potential applications. As a result, studies have been developed to address the dispersion problem. The solution is in modifying the surfaces of the nanotubes covalently or non-covalently with a desired dispersant. Various materials have been employed for this purpose out of which polymers are the most common. Non-covalent functionalization of CNTs via polymer wrapping represents an attractive method to obtain a stable and homogenous CNTs dispersion. This method is able to change the surface properties of the nanotubes without destroying their intrinsic structure and preserving their properties. This thesis explores and studies the surface modification and solublization of pristine single and multiwalled carbon nanotubes via a simple solution mixing technique through non-covalent interactions of CNTs with various anionic and cationic conjugated polyelectrolytes (CPEs). The work includes studying the interaction of various poly(phenylene ethynylene) electrolytes with MWCNTs and an imidazolium functionalized poly(3-hexylthiophene) with SWCNTs. Our work here focuses on the noncovalent modifications of carbon nanotubes using novel CPEs in order to use these resulting CPE/CNT complexes in various applications. Upon modifying the CNTs with the CPEs, the resulting CPE/CNT complex has been proven to be easily dispersed in various organic and aqueous solution with excellent homogeneity and stability for several months. This complex was then used as a nanofiller and was dispersed in another polymer matrix (poly(methyl methacrylate), PMMA). The PMMA/CPE/CNT composite materials were cast or electrospun depending on their desired application. The presence of the CPE modified CNTs in the polymer matrix has been proven to enhance

  11. Handbook of polymer nanocomposites processing, performance and application

    CERN Document Server

    Mohanty, Amar; Misra, Manjusri; Kar, Kamal K; Pandey, Jitendra; Rana, Sravendra; Takagi, Hitoshi; Nakagaito, Antonio; Kim, Hyun-Joong

    Volume A forms one volume of a Handbook about Polymer Nanocomposites. In some 20 chapters the preparation, architecture, characterisation, properties and application of polymer nanocomposites are discussed by experts in their respective fields.

  12. Spectral Signatures of Polarons in Conjugated Co-polymers

    NARCIS (Netherlands)

    Wiebeler, Christian; Tautz, Raphael; Feldmann, Jochen; von Hauff, Elizabeth; Da Como, Enrico; Schumacher, Stefan

    2013-01-01

    We study electronic and optical properties of the low-bandgap co-polymer PCPDT-BT (poly-cyclopentadithiophene-co-benzothiadiazole) and compare it with the corresponding homo-polymer PCPDT (poly-cyclopentadithiophene). We investigate the linear absorptivity in these systems for neutral molecules and

  13. Poly(2-oxazoline)-Antibiotic Conjugates with Penicillins.

    Science.gov (United States)

    Schmidt, Martin; Bast, Livia K; Lanfer, Franziska; Richter, Lena; Hennes, Elisabeth; Seymen, Rana; Krumm, Christian; Tiller, Joerg C

    2017-09-20

    The conjugation of antibiotics with polymers is rarely done, but it might be a promising alternative to low-molecular-weight derivatization. The two penicillins penicillin G (PenG) and penicillin V (PenV) were attached to the end groups of different water-soluble poly(2-oxazoline)s (POx) via their carboxylic acid function. This ester group was shown to be more stable against hydrolysis than the β-lactam ring of the penicillins. The conjugates are still antimicrobially active and up to 20 times more stable against penicillinase catalyzed hydrolysis. The antibiotic activity of the conjugates against Staphylococcus aureus in the presence of penicillinase is up to 350 times higher compared with the free antibiotics. Conjugates with a second antimicrobial function, a dodecyltrimethylammonium group (DDA-X), at the starting end of the PenG and PenV POx conjugates are more antimicrobially active than the conjugates without DDA-X and show high activity in the presence of penicillinase. For example, the conjugates DDA-X-PEtOx-PenG and DDA-X-PEtOx-PenV are 200 to 350 times more active against S. aureus in the presence of penicillinase and almost as effective as the penicillinase stable cloxacollin (Clox) under these conditions. These conjugates show even greater activity compared to cloxacollin without this enzyme present. Further, both conjugates kill Escherichia coli more effectively than PenG and Clox.

  14. Photovoltaic and Electroluminescence Characters in Hybrid ZnO and Conjugated Polymer Bulk Heterojunction Devices

    Institute of Scientific and Technical Information of China (English)

    LIU Jun-Peng; QU Sheng-Chun; XU Ying; CHEN Yong-Hai; ZENG Xiang-Bo; WANG Zhi-Jie; ZHOU Hui-Ying; WANG Zhan-Guo

    2007-01-01

    We report electroluminescence in hybrid ZnO and conjugated polymer poly[2-methoxy-5-(3',7'-dimethyloctyloxy)-1,4-phenylenevinylene] (MDMO-PPV) bulk heterojunction photovoltaic cells. Photoluminescence quenching experimental results indicate that the ultrafast photoinduced electron transfer occurs from MDMO-PPV to ZnO under illumination. The ultrafast photoinduced electron transfer effect is induced because ZnO has an electron affinity about 1.2 eV greater than that of MDMO-PPV. Electron 'back transfer' can occur if the interfacial barrier between ZnO and MDMO-PPV can be overcome by applying a substantial electric field. Therefore, electroluminescence action due to the fact that the back transfer effect can be observed in the ZnO: MDMO-PPV devices since a forward bias is applied. The photovoltaic and electroluminescence actions in the same ZnO: MDMO-PPV device can be induced by different injection ways: photoinjection and electrical injection. The devices are expected to provide an opportunity for dual functionality devices with photovoltaic effect and electroluminescence character.

  15. Surface functionalization of quantum dots with fine-structured pH-sensitive phospholipid polymer chains.

    Science.gov (United States)

    Liu, Yihua; Inoue, Yuuki; Ishihara, Kazuhiko

    2015-11-01

    To add novel functionality to quantum dots (QDs), we synthesized water-soluble and pH-responsive block-type polymers by reversible addition-fragmentation chain transfer (RAFT) polymerization. The polymers were composed of cytocompatible 2-methacryloyloxyethyl phosphorylcholine (MPC) polymer segments, which contain a small fraction of active ester groups and can be used to conjugate biologically active compounds to the polymer, and pH-responsive poly(2-(N,N-diethylamino) ethyl methacrylate (DEAEMA)) segments. One terminal of the polymer chain had a hydrophobic alkyl group that originated from the RAFT initiator. This hydrophobic group can bind to the hydrophobic layer on the QD surface. A fluorescent dye was conjugated to the polymer chains via the active ester group. The block-type polymers have an amphiphilic nature in aqueous medium. The polymers were thus easily bound to the QD surface upon evaporation of the solvent from a solution containing the block-type polymer and QDs, yielding QD/fluorescence dye-conjugated polymer hybrid nanoparticles. Fluorescence resonance energy transfer (FRET) between the QDs (donors) and the fluorescent dye molecules (acceptors) was used to obtain information on the conformational dynamics of the immobilized polymers. Higher FRET efficiency of the QD/fluorescent dye-conjugated polymer hybrid nanoparticles was observed at pH 7.4 as compared to pH 5.0 due to a stretching-shrinking conformational motion of the poly(DEAEMA) segments in response to changes in pH. We concluded that the block-type MPC polymer-modified nanoparticles could be used to evaluate the pH of cells via FRET fluorescence based on the cytocompatibility of the MPC polymer. Copyright © 2015 Elsevier B.V. All rights reserved.

  16. Conjugated polymer with carboxylate groups-Hg2 + system as a turn-on fluorescence probe for label-free detection of cysteine-containing compounds

    Science.gov (United States)

    Mi, Hongyu; Guan, Mingming; Liu, Jilin; Shan, Hongyan; Fei, Qiang; Huan, Yanfu; Feng, Guodong

    2017-04-01

    In this work, a turn on fluorescent sensor, based on Hg2 + coordination conjugated polymer, was developed to detect cysteine-containing compounds. The fluorescence of conjugated polymer (poly(2,5-bis (sodium 4-oxybutyrate) -1,4 - phenylethynylene-alt-1,4-phenyleneethynylene; PPE-OBS) would be quenched by Hg2 + because of the coordination-induced aggregation and electron transfers of PPE-OBS toward Hg2 +. When there were some cysteine-containing compounds in PPE-OBS-Hg2 + system, the fluorescence of PPE-OBS would be recovered. It indicated that the PPE-OBS-Hg2 + system could be used to detect cysteine-containing compounds. Under the optimized conditions, the experiment results showed that there were particularly linear range, high sensitivity and selectivity over other amino acids. The limit of detection (LOD) of cysteine (Cys), homocysteine (Hcy) and glutathione (GSH) were 0.725 μmol L- 1, 0.982 μmol L- 1 and 1.21 μmol L- 1 by using this sensor. In addition, Cys standard recovery in several green tea drink and honey samples was also demonstrated. The recovery of Cys was range from 96.3 to 105.0% and RSD was less than 3.25%. The satisfactory results demonstrated that the proposed method could be as a potential fluorescent method for determining cysteine-containing compounds in real samples.

  17. Antiviral Polymer Therapeutics

    DEFF Research Database (Denmark)

    Smith, Anton Allen Abbotsford

    2014-01-01

    polymerized in a controlled manner with carrier monomers of historically proven biocompatible polymers. The carrier polymers, the loading of ribavirin as well as the size of the polymer were varied systematically with the aid of an automated synthesis platform. These polymers were tested in a cellular assay...... of reversible-addition-fragmentation chain transfer polymerization, which not only controls the size of polymer, but also allows the introduction of a terminal amine on the polymer which can be used for further conjugation. This has allowed for not only fluorescent labeling of the polymer, but also protein...... is mediated through specific transporters, it is thought that the accumulation can be alleviated through the attachment of ribavirin to a macromolecule. To this end, ribavirin was enzymatically modified into a monomer compatible with controlled polymerization techniques. The ribavirin monomers were...

  18. Direct Cytoplasmic Delivery and Nuclear Targeting Delivery of HPMA-MT Conjugates in a Microtubules Dependent Fashion.

    Science.gov (United States)

    Zhong, Jiaju; Zhu, Xi; Luo, Kui; Li, Lian; Tang, Manlin; Liu, Yanxi; Zhou, Zhou; Huang, Yuan

    2016-09-06

    As the hearts of tumor cells, the nucleus is the ultimate target of many chemotherapeutic agents and genes. However, nuclear drug delivery is always hampered by multiple intracellular obstacles, such as low efficiency of lysosome escape and insufficient nuclear trafficking. Herein, an N-(2-hydroxypropyl) methacrylamide (HPMA) polymer-based drug delivery system was designed, which could achieve direct cytoplasmic delivery by a nonendocytic pathway and transport into the nucleus in a microtubules dependent fashion. A special targeting peptide (MT), derived from an endogenic parathyroid hormone-related protein, was conjugated to the polymer backbone, which could accumulate into the nucleus a by microtubule-mediated pathway. The in vitro studies found that low temperature and NaN3 could not influence the cell internalization of the conjugates. Besides, no obvious overlay of the conjugates with lysosome demonstrated that the polymer conjugates could enter the tumor cell cytoplasm by a nonendocytic pathway, thus avoiding the drug degradation in the lysosome. Furthermore, after suppression of the microtubule dynamics with microtubule stabilizing docetaxel (DTX) and destabilizing nocodazole (Noc), the nuclear accumulation of polymeric conjugates was significantly inhibited. Living cells fluorescence recovery after photobleaching study found that the nuclear import rate of conjugates was 2-fold faster compared with the DTX and Noc treated groups. These results demonstrated that the conjugates transported into the nucleus in a microtubules dependent way. Therefore, in addition to direct cytoplasmic delivery, our peptide conjugated polymeric platform could simultaneously mediate nuclear drug accumulation, which may open a new path for further intracellular genes/peptides delivery.

  19. Semiconductor-nanocrystal/conjugated polymer thin films

    Science.gov (United States)

    Alivisatos, A. Paul; Dittmer, Janke J.; Huynh, Wendy U.; Milliron, Delia

    2014-06-17

    The invention described herein provides for thin films and methods of making comprising inorganic semiconductor-nanocrystals dispersed in semiconducting-polymers in high loading amounts. The invention also describes photovoltaic devices incorporating the thin films.

  20. Neutral Polymer Micelle Carriers with pH-Responsive, Endosome-Releasing Activity Modulate Antigen Trafficking to Enhance CD8 T-Cell Responses

    Science.gov (United States)

    Keller, Salka; Wilson, John T; Patilea, Gabriela I; Kern, Hanna B; Convertine, Anthony J; Stayton, Patrick S

    2014-01-01

    Synthetic subunit vaccines need to induce CD8+ cytotoxic T-cell (CTL) responses for effective vaccination against intracellular pathogens. Most subunit vaccines primarily generate humoral immune responses, with a weaker than desired CD8+ cytotoxic T-cell response. Here, a neutral, pH-responsive polymer micelle carrier that alters intracellular antigen trafficking was shown to enhance CD8+ T-cell responses with a correlated increase in cytosolic delivery and a decrease in exocytosis. Polymer diblock carriers consisted of a N-(2-hydroxypropyl) methacrylamide corona block with pendant pyridyl disulfide groups for reversible conjugation of thiolated ovalbumin, and a tercopolymer ampholytic core-forming block composed of propylacrylic acid (PAA), dimethylaminoethyl methacrylate (DMAEMA), and butyl methacrylate (BMA). The diblock copolymers self-assembled into 25–30 nm diameter micellar nanoparticles. Conjugation of ovalbumin to the micelles significantly enhanced antigen cross-presentation in vitro relative to free ovalbumin, an unconjugated physical mixture of ovalbumin and polymer, and a non pH-responsive micelle-ovalbumin control. Mechanistic studies in a murine dendritic cell line (DC2.4) demonstrated micelle-mediated enhancements in intracellular antigen retention and cytosolic antigen accumulation. Approximately 90% of initially internalized ovalbumin-conjugated micelles were retained in cells after 1.5 h, compared to only ~40% for controls. Furthermore, cells dosed with conjugates displayed 67-fold higher cytosolic antigen levels relative to soluble ovalbumin 4 h post uptake. Subcutaneous immunization of mice with ovalbumin-polymer conjugates significantly enhanced antigen-specific CD8+ T cell responses (0.4 % IFN-γ+ of CD8+) compared to immunization with soluble protein, ovalbumin and polymer mixture, and the control micelle without endosome-releasing activity. Additionally, pH-responsive carrier facilitated antigen delivery to antigen presenting cells in the

  1. Neutral polymer micelle carriers with pH-responsive, endosome-releasing activity modulate antigen trafficking to enhance CD8(+) T cell responses.

    Science.gov (United States)

    Keller, Salka; Wilson, John T; Patilea, Gabriela I; Kern, Hanna B; Convertine, Anthony J; Stayton, Patrick S

    2014-10-10

    Synthetic subunit vaccines need to induce CD8(+) cytotoxic T cell (CTL) responses for effective vaccination against intracellular pathogens. Most subunit vaccines primarily generate humoral immune responses, with a weaker than desired CD8(+) cytotoxic T cell response. Here, a neutral, pH-responsive polymer micelle carrier that alters intracellular antigen trafficking was shown to enhance CD8(+) T cell responses with a correlated increase in cytosolic delivery and a decrease in exocytosis. Polymer diblock carriers consisted of a N-(2-hydroxypropyl) methacrylamide corona block with pendent pyridyl disulfide groups for reversible conjugation of thiolated ovalbumin, and a tercopolymer ampholytic core-forming block composed of propylacrylic acid (PAA), dimethylaminoethyl methacrylate (DMAEMA), and butyl methacrylate (BMA). The diblock copolymers self-assembled into 25-30nm diameter micellar nanoparticles. Conjugation of ovalbumin to the micelles significantly enhanced antigen cross-presentation in vitro relative to free ovalbumin, an unconjugated physical mixture of ovalbumin and polymer, and a non-pH-responsive micelle-ovalbumin control. Mechanistic studies in a murine dendritic cell line (DC 2.4) demonstrated micelle-mediated enhancements in intracellular antigen retention and cytosolic antigen accumulation. Approximately 90% of initially internalized ovalbumin-conjugated micelles were retained in cells after 1.5h, compared to only ~40% for controls. Furthermore, cells dosed with conjugates displayed 67-fold higher cytosolic antigen levels relative to soluble ovalbumin 4h post uptake. Subcutaneous immunization of mice with ovalbumin-polymer conjugates significantly enhanced antigen-specific CD8(+) T cell responses (0.4% IFN-γ(+) of CD8(+)) compared to immunization with soluble protein, ovalbumin and polymer mixture, and the control micelle without endosome-releasing activity. Additionally, pH-responsive carrier facilitated antigen delivery to antigen presenting cells

  2. Synthesis of a conjugated pyrrolopyridazinedione–benzodithiophene (PPD–BDT) copolymer and its application in organic and hybrid solar cells

    KAUST Repository

    Knall, Astrid-Caroline

    2017-03-30

    Herein, we describe the synthesis and characterization of a conjugated donor–acceptor copolymer consisting of a pyrrolopyridazinedione (PPD) acceptor unit, and a benzodithiophene (BDT) donor unit. The polymerization was done via a Stille cross-coupling polycondensation. The resulting PPD–BDT copolymer revealed an optical bandgap of 1.8 eV and good processability from chlorobenzene solutions. In an organic solar cell in combination with PC70BM, the polymer led to a power conversion efficiency of 4.5%. Moreover, the performance of the copolymer was evaluated in polymer/nanocrystal hybrid solar cells using non-toxic CuInS2 nanocrystals as inorganic phase, which were prepared from precursors directly in the polymer matrix without using additional capping ligands. The PPD–BDT/CuInS2 hybrid solar cells showed comparably high photovoltages and a power conversion efficiency of 2.2%.Graphical abstract

  3. Synthesis of a conjugated pyrrolopyridazinedione-benzodithiophene (PPD-BDT) copolymer and its application in organic and hybrid solar cells.

    Science.gov (United States)

    Knall, Astrid-Caroline; Jones, Andrew O F; Kunert, Birgit; Resel, Roland; Reishofer, David; Zach, Peter W; Kirkus, Mindaugas; McCulloch, Iain; Rath, Thomas

    2017-01-01

    Herein, we describe the synthesis and characterization of a conjugated donor-acceptor copolymer consisting of a pyrrolopyridazinedione (PPD) acceptor unit, and a benzodithiophene (BDT) donor unit. The polymerization was done via a Stille cross-coupling polycondensation. The resulting PPD-BDT copolymer revealed an optical bandgap of 1.8 eV and good processability from chlorobenzene solutions. In an organic solar cell in combination with PC 70 BM, the polymer led to a power conversion efficiency of 4.5%. Moreover, the performance of the copolymer was evaluated in polymer/nanocrystal hybrid solar cells using non-toxic CuInS 2 nanocrystals as inorganic phase, which were prepared from precursors directly in the polymer matrix without using additional capping ligands. The PPD-BDT/CuInS 2 hybrid solar cells showed comparably high photovoltages and a power conversion efficiency of 2.2%.

  4. Regioregular narrow-bandgap-conjugated polymers for plastic electronics

    Science.gov (United States)

    Ying, Lei; Huang, Fei; Bazan, Guillermo C.

    2017-03-01

    Progress in the molecular design and processing protocols of semiconducting polymers has opened significant opportunities for the fabrication of low-cost plastic electronic devices. Recent studies indicate that field-effect transistors and organic solar cells fabricated using narrow-bandgap regioregular polymers with translational symmetries in the direction of the backbone vector often outperform those containing analogous regiorandom polymers. This review addresses the cutting edge of regioregularity chemistry, in particular how to control the spatial distribution in the molecular structures and how this order translates to more ordered bulk morphologies. The effect of regioregularity on charge transport and photovoltaic properties is also outlined.

  5. Dependence of crystallite formation and preferential backbone orientations on the side chain pattern in PBDTTPD polymers

    KAUST Repository

    El Labban, Abdulrahman

    2014-11-26

    (Figure Presented) Alkyl substituents appended to the π-conjugated main chain account for the solution-processability and film-forming properties of most π-conjugated polymers for organic electronic device applications, including field-effect transistors (FETs) and bulk-heterojunction (BHJ) solar cells. Beyond film-forming properties, recent work has emphasized the determining role that side-chain substituents play on polymer self-assembly and thin-film nanostructural order, and, in turn, on device performance. However, the factors that determine polymer crystallite orientation in thin-films, implying preferential backbone orientation relative to the device substrate, are a matter of some debate, and these structural changes remain difficult to anticipate. In this report, we show how systematic changes in the side-chain pattern of poly(benzo[1,2-b:4,5-b′]dithiophene-alt-thieno[3,4-c]pyrrole-4,6-dione) (PBDTTPD) polymers can (i) influence the propensity of the polymer to order in the π-stacking direction, and (ii) direct the preferential orientation of the polymer crystallites in thin films (e.g., "face-on" vs "edge-on"). Oriented crystallites, specifically crystallites that are well-ordered in the π-stacking direction, are believed to be a key contributor to improved thin-film device performance in both FETs and BHJ solar cells.

  6. Photophysics of conjugated polymers: interplay between Förster energy migration and defect concentration in shaping a photochemical funnel in PPV.

    Science.gov (United States)

    Saini, Sangeeta; Bagchi, Biman

    2010-07-21

    Recent single molecule experiments have suggested the existence of a photochemical funnel in the photophysics of conjugated polymers, like poly[2-methoxy-5-(2'-ethylhexyl)oxy-1,4-phenylenevinylene] (MEH-PPV). The funnel is believed to be a consequence of the presence of conformational or chemical defects along the polymer chain and efficient non-radiative energy transfer among different chromophore segments. Here we address the effect of the excitation energy dynamics on the photophysics of PPV. The PPV chain is modeled as a polymer with the length distribution of chromophores given either by a Gaussian or by a Poisson distribution. We observe that the Poisson distribution of the segment lengths explains the photophysics of PPV better than the Gaussian distribution. A recently proposed version of an extended 'particle-in-a-box' model is used to calculate the exciton energies and the transition dipole moments of the chromophores, and a master equation to describe the excitation energy transfer among different chromophores. The rate of energy transfer is assumed to be given here, as a first approximation, by the well-known Förster expression. The observed excitation population dynamics confirms the photochemical funneling of excitation energy from shorter to longer chromophores of the polymer chain. The time scale of spectral shift and energy transfer for our model polymer, with realistic values of optical parameters, is in the range of 200-300 ps. We find that the excitation energy may not always migrate towards the longest chromophore segments in the polymer chain as the efficiency of energy transfer between chromophores depends on the separation distance between the two and their relative orientation.

  7. Electrical characterization of fluorinated benzothiadiazole based conjugated copolymer – a promising material for high-performance solar cells

    Directory of Open Access Journals (Sweden)

    J. Toušek

    2015-12-01

    Full Text Available Measurements of electrical conductivity, electron work function, carrier mobility of holes and the diffusion length of excitons were performed on samples of conjugated polymers relevant to polymer solar cells. A state of the art fluorinated benzothiadiazole based conjugated copolymer (PBDTTHD − DTBTff was studied and benchmarked against the reference polymer poly-3-hexylthiophene (P3HT. We employed, respectively, four electrode conductivity measurements, Kelvin probe work function measurements, carrier mobility using charge extraction by linearly increasing voltage (CELIV measurements and diffusion length determinaton using surface photovoltage measurements.

  8. Polymers in life sciences: Pharmaceutical and biomedical applications

    Science.gov (United States)

    Barba, Anna Angela; Dalmoro, Annalisa; d'Amore, Matteo; Lamberti, Gaetano; Cascone, Sara; Titomanlio, Giuseppe

    2015-12-01

    This paper deals with the work done by prof. Titomanlio and his group in the fields of pharmaceutical and biomedical applications of polymers. In particular, the main topics covered are: i) controlled drug release from pharmaceuticals based on hydrogel for oral delivery of drugs; ii) production and characterization of micro and nanoparticles based on stimuli-responsive polymers; iii) use of polymers for coronary stent gel-paving; iv) design and realization of novel methods (in-vitro and in-silico) to test polymer-based pharmaceuticals.

  9. Conducting polymer nanostructures: template synthesis and applications in energy storage.

    Science.gov (United States)

    Pan, Lijia; Qiu, Hao; Dou, Chunmeng; Li, Yun; Pu, Lin; Xu, Jianbin; Shi, Yi

    2010-07-02

    Conducting polymer nanostructures have received increasing attention in both fundamental research and various application fields in recent decades. Compared with bulk conducting polymers, conducting polymer nanostructures are expected to display improved performance in energy storage because of the unique properties arising from their nanoscaled size: high electrical conductivity, large surface area, short path lengths for the transport of ions, and high electrochemical activity. Template methods are emerging for a sort of facile, efficient, and highly controllable synthesis of conducting polymer nanostructures. This paper reviews template synthesis routes for conducting polymer nanostructures, including soft and hard template methods, as well as its mechanisms. The application of conducting polymer mesostructures in energy storage devices, such as supercapacitors and rechargeable batteries, are discussed.

  10. Conducting Polymer Nanostructures: Template Synthesis and Applications in Energy Storage

    Directory of Open Access Journals (Sweden)

    Lijia Pan

    2010-07-01

    Full Text Available Conducting polymer nanostructures have received increasing attention in both fundamental research and various application fields in recent decades. Compared with bulk conducting polymers, conducting polymer nanostructures are expected to display improved performance in energy storage because of the unique properties arising from their nanoscaled size: high electrical conductivity, large surface area, short path lengths for the transport of ions, and high electrochemical activity. Template methods are emerging for a sort of facile, efficient, and highly controllable synthesis of conducting polymer nanostructures. This paper reviews template synthesis routes for conducting polymer nanostructures, including soft and hard template methods, as well as its mechanisms. The application of conducting polymer mesostructures in energy storage devices, such as supercapacitors and rechargeable batteries, are discussed.

  11. Polyvinyl alcohol composite nanofibres containing conjugated levofloxacin-chitosan for controlled drug release

    International Nuclear Information System (INIS)

    Jalvandi, Javid; White, Max; Gao, Yuan; Truong, Yen Bach; Padhye, Rajiv; Kyratzis, Ilias Louis

    2017-01-01

    A range of biodegradable drug-nanofibres composite mats have been reported as drug delivery systems. However, their main disadvantage is the rapid release of the drug immediately after application. This paper reports an improved system based on the incorporation of drug conjugated-chitosan into polyvinyl alcohol (PVA) nanofibers. The results showed that controlled release of levofloxacin (LVF) could be achieved by covalently binding LVF to low molecular weight chitosan (CS) via a cleavable amide bond and then blending the conjugated CS with polyvinyl alcohol (PVA) nanofibres prior to electrospinning. PVA/LVF and PVA-CS/LVF nanofibres were fabricated as controls. The conjugated CS-LVF was characterized by FTIR, DSC, TGA and 1 H NMR. Scanning electron microscopy (SEM) showed that the blended CS-PVA nanofibres had a reduced fibre diameter compared to the controls. Drug release profiles showed that burst release was decreased from 90% in the control PVA/LVF electrospun mats to 27% in the PVA/conjugated CS-LVF mats after 8 h in phosphate buffer at 37 °C. This slower release is due to the cleavable bond between LVF and CS that slowly hydrolysed over time at neutral pH. The results indicate that conjugation of the drug to the polymer backbone is an effective way of minimizing burst release behaviour and achieving sustained release of the drug, LVF. - Highlights: • A novel drug delivery system for controlled release of drug was designed. • Composite PVA/conjugated CS-LVF nanofibres was fabricated by electrospinning. • Conjugated chitosan and composite nanofibres were characterized by various techniques. • Release profiles of drug were significantly improved in composite nanofibres containing drug conjugated chitosan.

  12. Polyvinyl alcohol composite nanofibres containing conjugated levofloxacin-chitosan for controlled drug release

    Energy Technology Data Exchange (ETDEWEB)

    Jalvandi, Javid, E-mail: Javid.jlv@gmail.com [CSIRO, Manufacturing Flagship, Bayview Ave, Clayton, Victoria 3168 (Australia); School of Fashion and Textiles, College of Design and Social Context, RMIT University, 25 Dawson Street, Brunswick, Victoria 3056 (Australia); White, Max, E-mail: tamrak@bigpond.com [School of Fashion and Textiles, College of Design and Social Context, RMIT University, 25 Dawson Street, Brunswick, Victoria 3056 (Australia); Gao, Yuan, E-mail: Yuan.Gao@csiro.au [CSIRO, Manufacturing Flagship, Bayview Ave, Clayton, Victoria 3168 (Australia); Truong, Yen Bach, E-mail: Yen.truong@csiro.au [CSIRO, Manufacturing Flagship, Bayview Ave, Clayton, Victoria 3168 (Australia); Padhye, Rajiv, E-mail: rajiv.padhye@rmit.edu.au [School of Fashion and Textiles, College of Design and Social Context, RMIT University, 25 Dawson Street, Brunswick, Victoria 3056 (Australia); Kyratzis, Ilias Louis, E-mail: Louis.kyratzis@csiro.au [CSIRO, Manufacturing Flagship, Bayview Ave, Clayton, Victoria 3168 (Australia)

    2017-04-01

    A range of biodegradable drug-nanofibres composite mats have been reported as drug delivery systems. However, their main disadvantage is the rapid release of the drug immediately after application. This paper reports an improved system based on the incorporation of drug conjugated-chitosan into polyvinyl alcohol (PVA) nanofibers. The results showed that controlled release of levofloxacin (LVF) could be achieved by covalently binding LVF to low molecular weight chitosan (CS) via a cleavable amide bond and then blending the conjugated CS with polyvinyl alcohol (PVA) nanofibres prior to electrospinning. PVA/LVF and PVA-CS/LVF nanofibres were fabricated as controls. The conjugated CS-LVF was characterized by FTIR, DSC, TGA and {sup 1}H NMR. Scanning electron microscopy (SEM) showed that the blended CS-PVA nanofibres had a reduced fibre diameter compared to the controls. Drug release profiles showed that burst release was decreased from 90% in the control PVA/LVF electrospun mats to 27% in the PVA/conjugated CS-LVF mats after 8 h in phosphate buffer at 37 °C. This slower release is due to the cleavable bond between LVF and CS that slowly hydrolysed over time at neutral pH. The results indicate that conjugation of the drug to the polymer backbone is an effective way of minimizing burst release behaviour and achieving sustained release of the drug, LVF. - Highlights: • A novel drug delivery system for controlled release of drug was designed. • Composite PVA/conjugated CS-LVF nanofibres was fabricated by electrospinning. • Conjugated chitosan and composite nanofibres were characterized by various techniques. • Release profiles of drug were significantly improved in composite nanofibres containing drug conjugated chitosan.

  13. Magnetoelectric polymer-based composites fundamentals and applications

    CERN Document Server

    Martins, Pedro

    2017-01-01

    The first book on this topic provides a comprehensive and well-structured overview of the fundamentals, synthesis and emerging applications of magnetoelectric polymer materials. Following an introduction to the basic aspects of polymer based magnetoelectric materials and recent developments, subsequent chapters discuss the various types as well as their synthesis and characterization. There then follows a review of the latest applications, such as memories, sensors and actuators. The book concludes with a look at future technological advances. An essential reference for entrants to the field as well as for experienced researchers.

  14. Dependency of non-homogeneity energy dispersion on absorbance line-shape of luminescent polymers

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Marcelo Castanheira da, E-mail: mar_castanheira@yahoo.com.br [Centro de Ciências Biológicas e da Natureza, Universidade Federal do Acre, CP 500, 69915-900 Rio Branco, AC (Brazil); Instituto de Física, Universidade Federal de Uberlândia, CP 593, 38400-902 Uberlândia, MG (Brazil); Santos Silva, H.; Silva, R.A.; Marletta, Alexandre [Instituto de Física, Universidade Federal de Uberlândia, CP 593, 38400-902 Uberlândia, MG (Brazil)

    2013-01-16

    In this paper, we study the importance of the non-homogeneity energy dispersion on absorption line-shape of luminescent polymers. The optical transition probability was calculated based on the molecular exciton model, Franck–Condon states, Gaussian distribution of non-entangled chains with conjugate degree n, semi-empirical parameterization of energy gap, electric dipole moment, and electron-vibrational mode coupling. Based on the approach of the energy gap functional dependence 1/n, the inclusion of the non-homogeneity energy dispersion 1/n{sup 2} is essential to obtain good experimental data agreement, mainly, where the absorption spectra display peaks width of about 65 meV. For unresolved absorption spectra, such as those observed for a large number of conjugated polymers processed via spin-coating technique, for example, the non-homogeneity energy dispersion parameterization is not significant. Results were supported by the application of the model for poly (p-phenylene vinylene) films.

  15. Nanocellulose in Polymer Composites and Biomedical: Research and Applications

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Yuan [ORNL; Tekinalp, Halil L [ORNL; Peter, William H [ORNL; Eberle, Cliff [ORNL; Naskar, Amit K [ORNL; Ozcan, Soydan [ORNL

    2014-01-01

    Nanocellulose materials are nano-sized cellulose fibers or crystals that are produced by bacteria or derived from plants. These materials exhibit exceptional strength characteristics, light weight, transparency, and excellent biocompatibility. Compared to some other nanomaterials, nanocellulose is renewable and less expensive to produce. As such, a wide range of applications for nanocellulose has been envisioned. Most extensively studied areas include polymer composites and biomedical applications. Cellulose nanofibrils and nanocrystals have been used to reinforce both thermoplastic and thermoset polymers. Given the hydrophilic nature of these materials, the interfacial properties with most polymers are often poor. Various surface modification procedures have thus been adopted to improve the interaction between polymer matrix and cellulose nanofibrils or nanocrystals. In addition, the applications of nanocellulose as biomaterials have been explored including wound dressing, tissue repair, and medical implants. Nanocellulose materials for wound healing and periodontal tissue recovery have become commercially available, demonstrating the great potential of nanocellulose as a new generation of biomaterials. In this review, we highlight the applications of nanocellulose as reinforcing fillers for composites and the effect of surface modification on the mechanical properties as well as the application as biomaterials.

  16. Hybrid ZnO:polymer bulk heterojunction solar cells from a ZnO precursor

    NARCIS (Netherlands)

    Beek, W.J.E.; Slooff, L.H.; Wienk, M.M.; Kroon, J.M.; Janssen, R.A.J.; Kafafi, Z.H.

    2005-01-01

    We describe a simple and new method to create hybrid bulk heterojunction solar cells consisting of ZnO and conjugated polymers. A gel-forming ZnO precursor, blended with conjugated polymers, is converted into crystalline ZnO at temperatures as low as 110 °C. In-situ formation of ZnO in MDMO-PPV

  17. .Pi.-conjugated donor and donor-acceptor metallo-polymers

    Czech Academy of Sciences Publication Activity Database

    Wild, A.; Schlütter, F.; Pavlov, G. M.; Friebe, Ch.; Festag, G.; Winter, A.; Hager, M. D.; Cimrová, Věra; Schubert, U.S.

    2010-01-01

    Roč. 31, 9-10 (2010), s. 868-874 ISSN 1022-1336 R&D Projects: GA MŠk(CZ) 1M06031; GA AV ČR IAA4050409 Institutional research plan: CEZ:AV0Z40500505 Keywords : analytical ultracentrifugation * conducting polymers * metallo-polymers Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 4.371, year: 2010

  18. The Recent Developments in Biobased Polymers toward General and Engineering Applications: Polymers that Are Upgraded from Biodegradable Polymers, Analogous to Petroleum-Derived Polymers, and Newly Developed

    OpenAIRE

    Nakajima, Hajime; Dijkstra, Peter; Loos, Katja

    2017-01-01

    The main motivation for development of biobased polymers was their biodegradability, which is becoming important due to strong public concern about waste. Reflecting recent changes in the polymer industry, the sustainability of biobased polymers allows them to be used for general and engineering applications. This expansion is driven by the remarkable progress in the processes for refining biomass feedstocks to produce biobased building blocks that allow biobased polymers to have more versati...

  19. High Efficiency Conjugated Polymer Donor and Fullerene Derivative Acceptor Photovoltaic Materials for Polymer Solar Cells%聚合物太阳能电池高效共轭聚合物给体和富勒烯受体光伏材料

    Institute of Scientific and Technical Information of China (English)

    李永舫

    2011-01-01

    Polymer solar ceils (PSCs) are composed of a blend film (active layer) of a conjugated polymer donor and a fullerene derivative acceptor sandwiched between a transparent ITO positive electrode and a low workfunction metal negative electrode. PSCs have become the hot research field in recent years, due to their unique advantages of simple fabrication, low cost, light weight and capability to be fabricated into flexible devices. The present research focus is to improve their photovoltaic power conversion efficiency (PCE), and the key aspects for improving PCE are high efficiency photovoltaic materials. In this paper,I will mainly introduce the recent research progress of Institute of Chemistry, Chinese Academy of Sciences (ICCAS) on the new conjugated polymer donor and fullerene derivative photovoltaic materials, including the donor materials of two-dimensional conjugated polymers with conjugated side chains, conjugated polymers with electron-withdrawing substituents for lower HOMO energy levels, D-A copolymer with broad absorption and lower HOMO energy levels,and the acceptor materials of indene-C60 bisadduct (ICBA) and indene-CT0 bisadduct. The highest PCE of the PSCs based on the conjugated polymer donor materials reached 7.59%, which is one of the highest efficiencies reported in literatures so for. The PSCs based on P3HT as donor and our ICBA as acceptor showed PCE higher than 7~ ,which is the highest efficiency for the PSCs based on P3HT.%聚合物太阳能电池(PSC)由共轭聚合物给体和富勒烯衍生物受体的共混膜(活性层)夹在ITO透明导电玻璃正极和低功函数金属负极之间所组成,具有制备过程简单、成本低、重量轻、可制备成柔性器件等突出优点,近年来成为国内外研究前沿和热点。当前研究的焦点是提高器件的光电能量转换效率,而提高效率的关键是高效共轭聚合物给体和富勒烯衍生物受体光伏材料。本文将重

  20. PEG conjugates in clinical development or use as anticancer agents: an overview.

    Science.gov (United States)

    Pasut, Gianfranco; Veronese, Francesco M

    2009-11-12

    During the almost forty years of PEGylation, several antitumour agents, either proteins, peptides or low molecular weight drugs, have been considered for polymer conjugation but only few entered clinical phase studies. The results from the first clinical trials have shared and improved the knowledge on biodistribution, clearance, mechanism of action and stability of a polymer conjugate in vivo. This has helped to design conjugates with improved features. So far, most of the PEG conjugates comprise of a protein, which in the native form has serious shortcomings that limit the full exploitation of its therapeutic action. The main issues can be short in vivo half-life, instability towards degrading enzymes or immunogenicity. PEGylation proved to be effective in shielding sensitive sites at the protein surface, such as antigenic epitopes and enzymatic degradable sequences, as well as in prolonging the drug half-life by decreasing the kidney clearance. In this review PEG conjugates of proteins or low molecular weight drugs, in clinical development or use as anticancer agents, will be taken into consideration. In the case of PEG-protein derivatives the most represented are depleting enzymes, which act by degrading amino acids essential for cancer cells. Interestingly, PEGylated conjugates have been also considered as adjuvant therapy in many standard anticancer protocols, in this regard the case of PEG-G-CSF and PEG-interferons will be presented.

  1. Imaging GABAc Receptors with Ligand-Conjugated Quantum Dots

    Directory of Open Access Journals (Sweden)

    Ian D. Tomlinson

    2007-01-01

    Full Text Available We report a methodology for labeling the GABAc receptor on the surface membrane of intact cells. This work builds upon our earlier work with serotonin-conjugated quantum dots and our studies with PEGylated quantum dots to reduce nonspecific binding. In the current approach, a PEGylated derivative of muscimol was synthesized and attached via an amide linkage to quantum dots coated in an amphiphilic polymer derivative of a modified polyacrylamide. These conjugates were used to image GABAC receptors heterologously expressed in Xenopus laevis oocytes.

  2. Application of electron beam, ion beam and positron beam to polymer sciences

    International Nuclear Information System (INIS)

    Tagawa, Seiichi

    1999-01-01

    Full text: Particle beams are finding increasing application in material sciences and the interest covers both applied as well as fundamental investigations. In the present talk application of electron and ion beams in several polymers such as polysilanes, polystyrene, polyolefins, polymethylmethacrylates and related polymers will be presented. It includes among other investigations (such as product analysis) pulse radiolysis studies and effect of LET on polymers. Importance of positron studies in material sciences especially bulk polymers is well documented. A relatively new technique, namely, positron beam application especially in thin film polymers is a new and emerging areas. The interest ranges from applied aspects as well as fundamental understanding of surfaces and interfaces. The present talk will detail the development of a pulsed positron beam using LINAC at Institute of Scientific and Industrial Research (ISIR) as well as its applications to polymer thin films

  3. Effect of thiolated polymers to textural and mucoadhesive properties of vaginal gel formulations prepared with polycarbophil and chitosan.

    Science.gov (United States)

    Cevher, Erdal; Sensoy, Demet; Taha, Mohamed A M; Araman, Ahmet

    2008-01-01

    The aim of this study was to design and evaluate of mucoadhesive gel formulations for the vaginal application of clomiphene citrate (CLM) for local treatment of human papilloma virus (HPV) infections. Chitosan (CHI) and polycarbophil (PC) were covalently modified using the thioglycolic acid and L-cysteine, respectively. The formation of thiol conjugates of chitosan (CHI-TG) and polycarbophil (PC-CYS) were confirmed by FT-IR analysis and PC-CYS and CHI-TG were found to have 148.42 +/- 4.16 and 41.17 +/- 2.34 micromol of thiol groups per gram of polymer, respectively. One percent CLM gels were prepared by combination of various concentrations of PC and CHI with thiolated conjugates of these polymers. Hardness, compressibility, elasticity, adhesiveness and cohesiveness of the gels were measured by Texture profile analysis and the vaginal mucoadhesion was investigated by mucoadhesion test. The increasing in the amount of the thiol conjugates was found to enhance the elasticity, cohesiveness, adhesiveness and mucoadhesion of the gel formulations but not their hardness and compressibility when compared to gels prepared using their respective parent formulations. Slower release rate of CLM from gels was achieved when the polymer concentrations were increased in the gel formulations. PC and its thiol conjugate were found to prolong the release of CLM longer than 70 h unlike gel formulations prepared using CHI and its thiol conjugate which were able to release CLM up to 12 h. Stability of CLM was preserved during the 3 month stability analysis under controlled room temperature and accelerated conditions.

  4. Specific bile acid radioimmunoassays for separate determinations of unconjugated cholic acid, conjugated cholic acid and conjugated deoxycholic acid in serum and their clinical application

    International Nuclear Information System (INIS)

    Matern, S.; Gerok, W.

    1977-01-01

    Specific radioimmunoassays for separate determinations of serum unconjugated cholic, conjugated cholic and conjugated deoxycholic acids have been developed. Prior to the radioimmunoassay, extraction of serum bile acids was performed with Amberlite XAD-2. Unconjugated cholic acid was separated from glyco- and taurocholic acids by thin-layer chromatography. At 50% displacement of bound labeled glyco[ 3 H]cholic acid using antiserum obtained after immunization with cholic acid-bovine serum albumin-conjugate the cross-reactivity of taurocholic acid was 100%, cholic acid 80%, glycochenodeoxycholic acid 10%, chenodeoxycholic acid 7%, conjugated deoxycholic acid 3%, and conjugated lithocholic acid 3 H]cholic acid was linear on a logit-log plot from 5 to 80 pmol of unlabeled glycocholic acid. Fasting serum conjugated cholic acid in healthy subjects was 0.68 +- 0.34 μmol/l. Unconjugated cholic acid was determined by a solid phase radioimmunoassay using the cholic acid antibody chemically bound to Sepharose. The displacement curve of [ 3 H]cholic acid in the solid phase radioimmunoassay was linear on a logit-log plot from 5 to 200 pmol of unlabeled cholic acid. The coefficient of variation between samples was 5%. Fasting serum conjugated deoxycholic acid concentrations in 10 healthy subjects ranged from 0.18 to 0.92 μmol/l determined by a radioimmunoassay using antiserum obtained after immunization with deoxycholic acid-bovine serum albumin-conjugate. The clinical application of these bile acid radioimmunoassays is shown by an 'oral cholate tolerance test' as a sensitive indicator of liver function and by an 'oral cholyglycine tolerance test' as a useful test for bile acid absorption. (orig.) [de

  5. Light-Emitting Devices Based on Pyridine-Containing Conjugated Polymers

    National Research Council Canada - National Science Library

    Wang, Y

    1997-01-01

    ...) as hole transporting/electron blocking polymer, which improves the device efficiency and brightness significantly due to the charge confinement and exciplex emission at the PVK/emitting polymer interface...

  6. Recent Development of Nanomaterial-Doped Conductive Polymers

    Science.gov (United States)

    Asyraf, Mohammad; Anwar, Mahmood; Sheng, Law Ming; Danquah, Michael K.

    2017-12-01

    Conductive polymers (CPs) have received significant research attention in material engineering for applications in microelectronics, micro-scale sensors, electromagnetic shielding, and micro actuators. Numerous research efforts have been focused on enhancing the conductivity of CPs by doping. Various conductive materials, such as metal nanoparticles and carbon-based nanoparticles, and structures, such as silver nanoparticles and graphene nanosheets, have been converted into polypyrrole and polypyrrole compounds as the precursors to developing hybrids, conjugates, or crystal nodes within the matrix to enhance the various structural properties, particularly the electrical conductivity. This article reviews nanomaterial doping of conductive polymers alongside technological advancements in the development and application of nanomaterial-doped polymeric systems. Emphasis is given to conductive nanomaterials such as nano-silver particles and carbon-based nanoparticles, graphene nano-sheets, fullerene, and carbon nanotubes (CNT) as dopants for polypyrrole-based CPs. The nature of induced electrical properties including electromagnetic absorption, electrical capacitance, and conductivities of polypyrrole systems is also discussed. The prospects and challenges associated with the development and application of CPs are also presented.

  7. Polymers in regenerative medicine biomedical applications from nano- to macro-structures

    CERN Document Server

    Monleon Pradas, Manuel

    2015-01-01

    Biomedical applications of Polymers from Scaffolds toNanostructures The ability of polymers to span wide ranges of mechanicalproperties and morph into desired shapes makes them useful for avariety of applications, including scaffolds, self-assemblingmaterials, and nanomedicines. With an interdisciplinary list ofsubjects and contributors, this book overviews the biomedicalapplications of polymers and focuses on the aspect of regenerativemedicine. Chapters also cover fundamentals, theories, and tools forscientists to apply polymers in the following ways: Matrix protein interactions with synthe

  8. Application of Thin Films of Conjugated Polymers in Novel LED's and Liquid Crystal 'Light Valves'

    National Research Council Canada - National Science Library

    MacDiarmid, A

    1997-01-01

    .... Flexible, completely organic polymer dispersed liquid crystal light valves have been fabricated from transparent plastic substrates on which a conducting film of polypyrrole has been deposited...

  9. Fluorinated Polymers as Smart Materials for Advanced Biomedical Applications

    Directory of Open Access Journals (Sweden)

    Vanessa F. Cardoso

    2018-02-01

    Full Text Available Fluorinated polymers constitute a unique class of materials that exhibit a combination of suitable properties for a wide range of applications, which mainly arise from their outstanding chemical resistance, thermal stability, low friction coefficients and electrical properties. Furthermore, those presenting stimuli-responsive properties have found widespread industrial and commercial applications, based on their ability to change in a controlled fashion one or more of their physicochemical properties, in response to single or multiple external stimuli such as light, temperature, electrical and magnetic fields, pH and/or biological signals. In particular, some fluorinated polymers have been intensively investigated and applied due to their piezoelectric, pyroelectric and ferroelectric properties in biomedical applications including controlled drug delivery systems, tissue engineering, microfluidic and artificial muscle actuators, among others. This review summarizes the main characteristics, microstructures and biomedical applications of electroactive fluorinated polymers.

  10. FTIR spectroscopy of electron irradiated polymers

    International Nuclear Information System (INIS)

    Finch, D.S.

    1988-04-01

    The chemical changes in electron beam irradiated polymers, in particular PVC, are considered in order to relate the formation of conjugated structures to changes in the electrical properties. Infrared spectroscopy has been used to measure these changes. Fourier Transform techniques and computing facilities make better data processing possible. A method for base line interpretation is demonstrated whereby a shift parallel to the abscisal axis in a region of the polymer that is non absorbing is used to evaluate the baseline. This technique has proved to be highly reproducible providing that the polymer films to be examined are optically homogeneous. Evaluation of the rate of decay of the total area of the carbon chlorine region of the polymer has been compared with the chlorine decay curve analysed by the measurement of x-ray emission during irradiation of bulk samples. The significant reduction in the evolution of atomic chlorine through x-ray analysis has been attributed to the trapping of HCl within the polymer film and its subsequent slow diffusion out of the polymer. With PVC, one of the main products as a result of irradiation is the formation of conjugated sequences. These were studied by the use of uv-visible spectroscopy. (author)

  11. Redox-active triazatruxene-based conjugated microporous polymers for high-performance supercapacitors† †Electronic supplementary information (ESI) available: Synthetic procedures and characterization data for all new compounds; general experimental method; thermogravimetry curves; PXRD patterns; SEM and TEM images; XPS spectra. See DOI: 10.1039/c6sc05532j Click here for additional data file.

    Science.gov (United States)

    Li, Xiang-Chun; Zhang, Yizhou; Wang, Chun-Yu; Wan, Yi

    2017-01-01

    Conjugated polymers (CPs) have been intensively explored for various optoelectronic applications in the last few decades. Nevertheless, CP based electrochemical energy storage devices such as supercapacitors remain largely unexplored. This is mainly owing to the low specific capacitance, poor structural/electrochemical stability, and low energy density of most existing CPs. In this contribution, a novel set of redox-active conjugated microporous polymers, TAT-CMP-1 and TAT-CMP-2, based on nitrogen-rich and highly conductive triazatruxene building blocks, were successfully designed and synthesized to explore their potential application as efficient and stable electrode materials for supercapacitors. Despite a moderate surface area of 88 m2 g–1 for TAT-CMP-1 and 106 m2 g–1 for TAT-CMP-2, exceptional specific capacitances of 141 F g–1 and 183 F g–1 were achieved at a current density of 1 A g–1. The resulting polymers exhibited unusually high areal specific capacitance (>160 μF cm–2), which is attributed to the pseudocapacitance resulting from redox-active structures with high nitrogen content. More importantly, the TAT-CMP-2 electrode exhibits excellent cycling stability: only 5% capacitance fading is observed after 10 000 cycles at a high current density of 10 A g–1, enabling the possible use of these materials as electrodes in electrochemical devices. PMID:28451362

  12. Electrical properties of .sigma.-conjugated polymers with additives and their applications in sensors

    Czech Academy of Sciences Publication Activity Database

    Nešpůrek, Stanislav; Wang, Geng; Böhm, S.; Kořínek, M.; Adler, H.-J.

    2004-01-01

    Roč. 210, - (2004), s. 513-521 ISSN 1022-1360. [International Symposium on Reactive Polymers in Inhomogeneous Systems, in Melts and at Interfaces /2./. Dresden, 28.09.2003-01.10.2003] R&D Projects: GA MŠk ME 440; GA MŠk OC D14.30 Institutional research plan: CEZ:AV0Z4050913 Keywords : polysilylenes * charge transport * doping Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.691, year: 2004

  13. Synthesis and Exciton Dynamics of Triplet Sensitized Conjugated Polymers

    KAUST Repository

    Andernach, Rolf

    2015-07-22

    We report the synthesis of a novel polythiophene-based host-guest copolymer incorporating a Pt-porphyrin complex (TTP-Pt) into the backbone for efficient singlet to triplet polymer exciton sensitization. We elucidated the exciton dynamics in thin films of the material by means of Transient Absorption Spectrosopcy (TAS) on multiple timescales and investigated the mechanism of triplet exciton formation. During sensitization, single exciton diffusion is followed by exciton transfer from the polymer backbone to the complex where it undergoes intersystem crossing to the triplet state of the complex. We directly monitored the triplet exciton back transfer from the Pt-porphyrin to the polymer and find that 60% of the complex triplet excitons are transferred with a time constant of 1087 ps. We propose an equilibrium between polymer and porphyrin triplet states as a result of the low triplet diffusion length in the polymer backbone and hence an increased local triplet population resulting in increased triplet-triplet annihilation. This novel system has significant implications for the design of novel materials for triplet sensitized solar cells and up-conversion layers.

  14. Laser surface texturing of polymers for biomedical applications

    Science.gov (United States)

    Riveiro, Antonio; Maçon, Anthony L. B.; del Val, Jesus; Comesaña, Rafael; Pou, Juan

    2018-02-01

    Polymers are materials widely used in biomedical science because of their biocompatibility, and good mechanical properties (which, in some cases, are similar to those of human tissues); however, these materials are, in general, chemically and biologically inert. Surface characteristics, such as topography (at the macro-, micro, and nanoscale), surface chemistry, surface energy, charge or wettability are interrelated properties, and they cooperatively influence the biological performance of materials when used for biomedical applications. They regulate the biological response at the implant/tissue interface (e.g., influencing the cell adhesion, cell orientation, cell motility, etc.). Several surface processing techniques have been explored to modulate these properties for biomedical applications. Despite their potentials, these methods have limitations that prevent their applicability. In this regard, laser-based methods, in particular laser surface texturing (LST), can be an interesting alternative. Different works have showed the potentiality of this technique to control the surface properties of biomedical polymers and enhance their biological performance; however, more research is needed to obtain the desired biological response. This work provides a general overview of the basics and applications of LST for the surface modification of polymers currently used in the clinical practice (e.g. PEEK, UHMWPE, PP, etc.). The modification of roughness, wettability, and their impact on the biological response is addressed to offer new insights on the surface modification of biomedical polymers.

  15. Ionic-Liquid-Based Polymer Electrolytes for Battery Applications.

    Science.gov (United States)

    Osada, Irene; de Vries, Henrik; Scrosati, Bruno; Passerini, Stefano

    2016-01-11

    The advent of solid-state polymer electrolytes for application in lithium batteries took place more than four decades ago when the ability of polyethylene oxide (PEO) to dissolve suitable lithium salts was demonstrated. Since then, many modifications of this basic system have been proposed and tested, involving the addition of conventional, carbonate-based electrolytes, low molecular weight polymers, ceramic fillers, and others. This Review focuses on ternary polymer electrolytes, that is, ion-conducting systems consisting of a polymer incorporating two salts, one bearing the lithium cation and the other introducing additional anions capable of plasticizing the polymer chains. Assessing the state of the research field of solid-state, ternary polymer electrolytes, while giving background on the whole field of polymer electrolytes, this Review is expected to stimulate new thoughts and ideas on the challenges and opportunities of lithium-metal batteries. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Polymers and its applications in agriculture

    Directory of Open Access Journals (Sweden)

    Priscila Milani

    2017-09-01

    Full Text Available Graphical Abstract Abstract Polymers are a class of soft materials with numerous and versatile mechanical and chemical properties that can be tuned specific to their application. Agriculture is an expanding area due to the requirement for indispensable food to meet the demands of a growing global population. Consequently, development of technology to improve the quality of the soil and agriculture manages is still under development. Intelligent agricultural supplies (controlled or slow release agrochemicals and superabsorbents and biosorbents contribute to an expanding niche using technology from polymers. This review elucidates the state-of-the-art and will discuss some important aspects of using polymers in intelligent fertilizers, as well as superabsorbent, biosorbent and biodegradation processes in agriculture that are environmentally, technically, socially, and economically sustainable.

  17. Cubosome formulations stabilized by a dansyl-conjugated block copolymer for possible nanomedicine applications.

    Science.gov (United States)

    Murgia, Sergio; Falchi, Angela Maria; Meli, Valeria; Schillén, Karin; Lippolis, Vito; Monduzzi, Maura; Rosa, Antonella; Schmidt, Judith; Talmon, Yeshayahu; Bizzarri, Ranieri; Caltagirone, Claudia

    2015-05-01

    We present here an innovative, fluorescent, monoolein-based cubosome dispersion. Rather than embedded within the monoolein palisade, the fluorescent imaging agent, namely dansyl, was conjugated to the terminal ethylene oxide moieties of the block copolymer Pluronic F108. We discuss the physicochemical and photophysical properties of this fluorescent Pluronic and of a cubosome formulation stabilized by a mixture of dansyl-conjugated and non-conjugated Pluronic, also including an anticancer drug (quercetin). Furthermore, we performed biocompatibility tests against HeLa cells to assess internalization and cytotoxicity features of this nanoparticles aqueous dispersion. Cryo-TEM, SAXS, and DLS analysis, proved the bicontinuous cubic inner nanostructure and the morphology of this fluorescent cubosome dispersion, while photophysical measurements and biocompatibility results basically validate their potential use for theranostic nanomedicine applications. Copyright © 2015 Elsevier B.V. All rights reserved.

  18. Nano-Star-Shaped Polymers for Drug Delivery Applications.

    Science.gov (United States)

    Yang, Da-Peng; Oo, Ma Nwe Nwe Linn; Deen, Gulam Roshan; Li, Zibiao; Loh, Xian Jun

    2017-11-01

    With the advancement of polymer engineering, complex star-shaped polymer architectures can be synthesized with ease, bringing about a host of unique properties and applications. The polymer arms can be functionalized with different chemical groups to fine-tune the response behavior or be endowed with targeting ligands or stimuli responsive moieties to control its physicochemical behavior and self-organization in solution. Rheological properties of these solutions can be modulated, which also facilitates the control of the diffusion of the drug from these star-based nanocarriers. However, these star-shaped polymers designed for drug delivery are still in a very early stage of development. Due to the sheer diversity of macromolecules that can take on the star architectures and the various combinations of functional groups that can be cross-linked together, there remain many structure-property relationships which have yet to be fully established. This review aims to provide an introductory perspective on the basic synthetic methods of star-shaped polymers, the properties which can be controlled by the unique architecture, and also recent advances in drug delivery applications related to these star candidates. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Radiation modification of polymers: fundamentals and applications

    International Nuclear Information System (INIS)

    Clough, R.L.

    2003-01-01

    When polymers were first exposed to ionizing radiation some 50 years ago, the resultant changes were found to be complex and relatively non-selective. Most importantly, irradiation was seen to give a mix of bond forming and bond breaking processes, and different polymer types were classified into two groups according to which process predominated. For polymers in the 'crosslinking' category, large industrial applications emerged within the first two decades of the initiation of this field, including heat shrink products, high performance wire insulation and tire manufacturing. There has been continuing work toward development of a wide range of new applications based on polymers and radiation, and this field remains quite active today. One approach to finding new commercial processes has been to take advantage of a variety of different radiation-induced phenomena (for example, uses for chain scission have emerged for enhancing the processing properties of various bulk polymers, for recycling of rubber, and for microlithography and LIGA). Another approach has taken advantage of progress in the science of radiation chemistry, by employing our increasing knowledge to enhance and/or reduce competing processes through the use of additives, the design of specialized resins, controlling gaseous atmospheres, varying processing conditions such as temperature, post-irradiation treatments, etc. This presentation will survey some of the exciting developments in polymer radiation processing, and will point out some of the underlying phenomena that are being manipulated to further their success. We will finish by describing progress on fundamental isotope-labeling studies of one longstanding mechanistic complexity, oxidation chemistry, which is critical in many radiation processing applications, such as retarding post-irradiation degradation problems, enhancing chain scission where desired, altering surface polarity, and providing a useful pretreatment in grafting schemes

  20. Development of polymers for large scale roll-to-roll processing of polymer solar cells

    DEFF Research Database (Denmark)

    Carlé, Jon Eggert

    Development of polymers for large scale roll-to-roll processing of polymer solar cells Conjugated polymers potential to both absorb light and transport current as well as the perspective of low cost and large scale production has made these kinds of material attractive in solar cell research....... The research field of polymer solar cells (PSCs) is rapidly progressing along three lines: Improvement of efficiency and stability together with the introduction of large scale production methods. All three lines are explored in this work. The thesis describes low band gap polymers and why these are needed....... Polymer of this type display broader absorption resulting in better overlap with the solar spectrum and potentially higher current density. Synthesis, characterization and device performance of three series of polymers illustrating how the absorption spectrum of polymers can be manipulated synthetically...

  1. Electrochemically deposited conducting polymers for reliable biomedical interfacing materials: Formulation, mechanical characterization, and failure analysis

    Science.gov (United States)

    Qu, Jing

    Conjugated polymers such as poly(3,4-ethylenedioxythiophene) (PEDOT) are of interest for a variety of applications including interfaces between electronic biomedical devices and living tissue. These polymers provide an improved interface compared to metal and semiconducting electrodes because of their ionic conductivity, relatively lower stiffness, and ability to incorporate biological molecules. Even though the signal transfer and biocompatibility of conjugated polymers are superior compared as the biointerfacing materials, the durability has been the weakest part for the long-term applications. Even though some efforts have been made to improve the durability of conjugated polymers, little quantitative information of the improved cohesion, adhesion and durability has been reported. In this thesis, the methods of improving the durability of conjugated polymer films, especially PEDOT, were investigated, including alternating the processing methods and components in synthesis. The 7-month in vivo testing showed that the durability of PEDOT films still needed to be improved. As a coating for biosignal transfer, the cohesion, adhesion and electrochemical stability of PEDOT are vital to determine the long-term performance. Not much information hd been developed around the cohesion and adhesion. A thin film cracking method was developed to measure the stiffness, strength and the interfacial shear strength (adhesion) of electrochemically deposited PEDOT. The estimated Young’s modulus of the PEDOT films was 2.6 ± 1.4 GPa, and the strain to failure was around 2%. The tensile strength was measured to be 56 ± 27 MPa. The effectiveness of crosslinker and adhesion promoter was demonstrated by this method. It was shown that 5 mole% addition of a tri-functional EDOT crosslinker (EPh) increased the tensile strength of the films to 283 ± 67 MPa, while the strain to failure remained about the same (2%). With the modification of EDOT-acid to the surface of stainless steel

  2. Structure/property relationships in polymer membranes for water purification and energy applications

    Science.gov (United States)

    Geise, Geoffrey

    Providing sustainable supplies of purified water and energy is a critical global challenge for the future, and polymer membranes will play a key role in addressing these clear and pressing global needs for water and energy. Polymer membrane-based processes dominate the desalination market, and polymer membranes are crucial components in several rapidly developing power generation and storage applications that rely on membranes to control rates of water and/or ion transport. Much remains unknown about the influence of polymer structure on intrinsic water and ion transport properties, and these relationships must be developed to design next generation polymer membrane materials. For desalination applications, polymers with simultaneously high water permeability and low salt permeability are desirable in order to prepare selective membranes that can efficiently desalinate water, and a tradeoff relationship between water/salt selectivity and water permeability suggests that attempts to prepare such materials should rely on approaches that do more than simply vary polymer free volume. One strategy is to functionalize hydrocarbon polymers with fixed charge groups that can ionize upon exposure to water, and the presence of charged groups in the polymer influences transport properties. Additionally, in many emerging energy applications, charged polymers are exposed to ions that are very different from sodium and chloride. Specific ion effects have been observed in charged polymers, and these effects must be understood to prepare charged polymers that will enable emerging energy technologies. This presentation discusses research aimed at further understanding fundamental structure/property relationships that govern water and ion transport in charged polymer films considered for desalination and electric potential field-driven applications that can help address global needs for clean water and energy.

  3. Approaches in biotechnological applications of natural polymers

    Directory of Open Access Journals (Sweden)

    José A. Teixeira

    2016-08-01

    Full Text Available Natural polymers, such as gums and mucilage, are biocompatible, cheap, easily available and non-toxic materials of native origin. These polymers are increasingly preferred over synthetic materials for industrial applications due to their intrinsic properties, as well as they are considered alternative sources of raw materials since they present characteristics of sustainability, biodegradability and biosafety. As definition, gums and mucilages are polysaccharides or complex carbohydrates consisting of one or more monosaccharides or their derivatives linked in bewildering variety of linkages and structures. Natural gums are considered polysaccharides naturally occurring in varieties of plant seeds and exudates, tree or shrub exudates, seaweed extracts, fungi, bacteria, and animal sources. Water-soluble gums, also known as hydrocolloids, are considered exudates and are pathological products; therefore, they do not form a part of cell wall. On the other hand, mucilages are part of cell and physiological products. It is important to highlight that gums represent the largest amounts of polymer materials derived from plants. Gums have enormously large and broad applications in both food and non-food industries, being commonly used as thickening, binding, emulsifying, suspending, stabilizing agents and matrices for drug release in pharmaceutical and cosmetic industries. In the food industry, their gelling properties and the ability to mold edible films and coatings are extensively studied. The use of gums depends on the intrinsic properties that they provide, often at costs below those of synthetic polymers. For upgrading the value of gums, they are being processed into various forms, including the most recent nanomaterials, for various biotechnological applications. Thus, the main natural polymers including galactomannans, cellulose, chitin, agar, carrageenan, alginate, cashew gum, pectin and starch, in addition to the current researches about them

  4. Self-Assembly of Telechelic Tyrosine End-Capped PEO Star Polymers in Aqueous Solution.

    Science.gov (United States)

    Edwards-Gayle, Charlotte J C; Greco, Francesca; Hamley, Ian W; Rambo, Robert P; Reza, Mehedi; Ruokolainen, Janne; Skoulas, Dimitrios; Iatrou, Hermis

    2018-01-08

    We investigate the self-assembly of two telechelic star polymer-peptide conjugates based on poly(ethylene oxide) (PEO) four-arm star polymers capped with oligotyrosine. The conjugates were prepared via N-carboxy anhydride-mediated ring-opening polymerization from PEO star polymer macroinitiators. Self-assembly occurs above a critical aggregation concentration determined via fluorescence probe assays. Peptide conformation was examined using circular dichroism spectroscopy. The structure of self-assembled aggregates was probed using small-angle X-ray scattering and cryogenic transmission electron microscopy. In contrast to previous studies on linear telechelic PEO-oligotyrosine conjugates that show self-assembly into β-sheet fibrils, the star architecture suppresses fibril formation and micelles are generally observed instead, a small population of fibrils only being observed upon pH adjustment. Hydrogelation is also suppressed by the polymer star architecture. These peptide-functionalized star polymer solutions are cytocompatible at sufficiently low concentration. These systems present tyrosine at high density and may be useful in the development of future enzyme or pH-responsive biomaterials.

  5. Factors Governing Intercalation of Fullerenes and Other Small Molecules Between the Side Chains of Semiconducting Polymers Used in Solar Cells

    KAUST Repository

    Miller, Nichole Cates; Cho, Eunkyung; Gysel, Roman; Risko, Chad; Coropceanu, Veaceslav; Miller, Chad E.; Sweetnam, Sean; Sellinger, Alan; Heeney, Martin; McCulloch, Iain; Bré das, Jean-Luc; Toney, Michael F.; McGehee, Michael D.

    2012-01-01

    bimolecular crystals did not form in the other studied polymer:nonfullerene blends, including those with both conjugated and non-conjugated small molecules. DSC and molecular simulations demonstrate that strong polymer-fullerene interactions can exist

  6. Multivalent conjugates of basic fibroblast growth factor enhance in vitro proliferation and migration of endothelial cells.

    Science.gov (United States)

    Zbinden, Aline; Browne, Shane; Altiok, Eda I; Svedlund, Felicia L; Jackson, Wesley M; Healy, Kevin E

    2018-05-01

    Growth factors hold great promise for regenerative therapies. However, their clinical use has been halted by poor efficacy and rapid clearance from tissue, necessitating the delivery of extremely high doses to achieve clinical effectiveness which has raised safety concerns. Thus, strategies to either enhance growth factor activity at low doses or to increase their residence time within target tissues are necessary for clinical success. In this study, we generated multivalent conjugates (MVCs) of basic fibroblast growth factor (bFGF), a key growth factor involved in angiogenesis and wound healing, to hyaluronic acid (HyA) polymer chains. Multivalent bFGF conjugates (mvbFGF) were fabricated with minimal non-specific interaction observed between bFGF and the HyA chain. The hydrodynamic radii of mvbFGF ranged from ∼50 to ∼75 nm for conjugation ratios of bFGF to HyA chains at low (10 : 1) and high (30 : 1) feed ratios, respectively. The mvbFGF demonstrated enhanced bioactivity compared to unconjugated bFGF in assays of cell proliferation and migration, processes critical to angiogenesis and tissue regeneration. The 30 : 1 mvbFGF outperformed the 10 : 1 conjugate, which could be due to either FGF receptor clustering or interference with receptor mediated internalization and signal deactivation. This study simultaneously investigated the role of both protein to polymer ratio and multivalent conjugate size on their bioactivity, and determined that increasing the protein-to-polymer ratio and conjugate size resulted in greater cell bioactivity.

  7. Detoxification of gold nanorods by conjugation with thiolated poly(ethylene glycol) and their assessment as SERS-active carriers of Raman tags

    Energy Technology Data Exchange (ETDEWEB)

    Boca, Sanda C; Astilean, Simion, E-mail: sboca@phys.ubbcluj.ro, E-mail: sastil@phys.ubbcluj.ro [Nanobiophotonics Center, Institute for Interdisciplinary Research in Nanobioscience, Babes-Bolyai University, Treboniu Laurian Street 42, 400271 Cluj-Napoca (Romania)

    2010-06-11

    We present an effective, low cost protocol to reduce the toxicity of gold nanorods induced by the presence of cetyltrimethylammonium bromide (CTAB) on their lateral surface as a result of the synthesis process. Here, we use thiolated methoxy-poly(ethylene) glycol (mPEG-SH) polymer to displace most of the CTAB bilayer cap from the particle surface. The detoxification process, chemical and structural stability of as-prepared mPEG-SH-conjugated gold nanorods were characterized using a number of techniques including localized surface plasmon resonance (LSPR), transmission electron microscopy (TEM) and surface-enhanced Raman spectroscopy (SERS). In view of future applications as near-infrared (NIR) nanoheaters in localized photothermal therapy of cancer, we investigated the thermal behaviour of mPEG-SH-conjugated gold nanorods above room temperature. We found a critical temperature at around 40 deg. C at which the adsorbed polymer layer is susceptible to undergo conformational changes. Additionally, we believe that such plasmonic nanoprobes could act as SERS-active carriers of Raman tags for application in cellular imaging. In this sense we successfully tested them as effective SERS substrates at 785 nm laser line with p-aminothiophenol (pATP) as a tag molecule.

  8. Detoxification of gold nanorods by conjugation with thiolated poly(ethylene glycol) and their assessment as SERS-active carriers of Raman tags

    Science.gov (United States)

    Boca, Sanda C.; Astilean, Simion

    2010-06-01

    We present an effective, low cost protocol to reduce the toxicity of gold nanorods induced by the presence of cetyltrimethylammonium bromide (CTAB) on their lateral surface as a result of the synthesis process. Here, we use thiolated methoxy-poly(ethylene) glycol (mPEG-SH) polymer to displace most of the CTAB bilayer cap from the particle surface. The detoxification process, chemical and structural stability of as-prepared mPEG-SH-conjugated gold nanorods were characterized using a number of techniques including localized surface plasmon resonance (LSPR), transmission electron microscopy (TEM) and surface-enhanced Raman spectroscopy (SERS). In view of future applications as near-infrared (NIR) nanoheaters in localized photothermal therapy of cancer, we investigated the thermal behaviour of mPEG-SH-conjugated gold nanorods above room temperature. We found a critical temperature at around 40 °C at which the adsorbed polymer layer is susceptible to undergo conformational changes. Additionally, we believe that such plasmonic nanoprobes could act as SERS-active carriers of Raman tags for application in cellular imaging. In this sense we successfully tested them as effective SERS substrates at 785 nm laser line with p-aminothiophenol (pATP) as a tag molecule.

  9. Detoxification of gold nanorods by conjugation with thiolated poly(ethylene glycol) and their assessment as SERS-active carriers of Raman tags

    International Nuclear Information System (INIS)

    Boca, Sanda C; Astilean, Simion

    2010-01-01

    We present an effective, low cost protocol to reduce the toxicity of gold nanorods induced by the presence of cetyltrimethylammonium bromide (CTAB) on their lateral surface as a result of the synthesis process. Here, we use thiolated methoxy-poly(ethylene) glycol (mPEG-SH) polymer to displace most of the CTAB bilayer cap from the particle surface. The detoxification process, chemical and structural stability of as-prepared mPEG-SH-conjugated gold nanorods were characterized using a number of techniques including localized surface plasmon resonance (LSPR), transmission electron microscopy (TEM) and surface-enhanced Raman spectroscopy (SERS). In view of future applications as near-infrared (NIR) nanoheaters in localized photothermal therapy of cancer, we investigated the thermal behaviour of mPEG-SH-conjugated gold nanorods above room temperature. We found a critical temperature at around 40 deg. C at which the adsorbed polymer layer is susceptible to undergo conformational changes. Additionally, we believe that such plasmonic nanoprobes could act as SERS-active carriers of Raman tags for application in cellular imaging. In this sense we successfully tested them as effective SERS substrates at 785 nm laser line with p-aminothiophenol (pATP) as a tag molecule.

  10. Piezoelectric Polymer Ultrasound Transducers and Its Biomedical Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Kang Lyeol; Cao, Yanggang [Department of Physics, Pukyong National University, Busan (Korea, Republic of)

    2012-10-15

    PVDF(poly vinylidene fluoride) and P(VDF-TrFE)(poly vinylidene fluoride-tetrafluoroethylene) are the typical piezoelectric polymers with unique properties. Even they are inferior to conventional piezoelectric ceramics PZT in electromechanical conversion efficiency and interior loss, though they are superior in receiving sensitivity and frequency bandwidth. Their acoustic impedances are relatively close to water or biological tissue and it is easier to make thin film than other piezoelectric materials. Furthermore, the film is so flexible that it is easy to attach on a complex surface. Those properties are suitable for the ultrasound transducers which are useful for medical and biological application, so that various types of polymer transducers have been developed. In this paper, several important considerations for design and fabrication of piezoelectric polymer transducers were described and their effect on the transducer performance were demonstrated through the KLM model analysis. Then, it was briefly reviewed about the structures of the polymer transducers developed for obtaining images as well as the characteristics of the images in several important medical and biological application fields.

  11. Synthesis, Morphologies and Building Applications of Nanostructured Polymers

    Directory of Open Access Journals (Sweden)

    Yong Lu

    2017-10-01

    Full Text Available Nanostructured polymers (NSPs are polymeric materials in the size of nanoscale, normally consisting of nanoparticles, nanofibers, nanowires, nanospheres and other morphologies. Polymer nanoparticles (PNPs can be fabricated either by physical methods (i.e., solvent evaporation, nanoprecipitation, salting out or by direct nanosynthesis, using micro- or nanoemulsions with nanoreactor compartments to perform polymerization. Polymer nanofibers (PNFs can be produced via various techniques and the most commonly used approach is electrospinning, whereby a charged solution of a polymer when exposed to an opposite high electric field is pulled into long thin nanofibers. NSPs in general exhibit enhanced properties such as excellent structural and mechanical properties, making them promising candidates for some particular building applications. A variety of PNFs have been developed and used for noise and air pollution filtration. Moreover, PNFs can also be fabricated with phase change materials which are usually employed for thermal energy storage in construction industry. In this review, we will summarize the morphologies and nanosynthesis methods of NSPs, in particular, PNPs and PNFs. In addition, representative NSPs mainly used in construction are introduced for building applications.

  12. Detection of bisphenol A in food packaging based on fluorescent conjugated polymer PPESO3 and enzyme system.

    Science.gov (United States)

    Huang, Hui; Li, Yongxin; Liu, Jintong; Tong, Jin; Su, Xingguang

    2015-10-15

    Bisphenol A (BPA) is a kind of carcinogen, which can interfere with the body's endocrine system. In this paper, a new kind of fluorescent sensor for BPA detection was established based on the fluorescent conjugated polymer PPESO3. The oxidative product of BPA is able to quench PPESO3 in the presence of HRP and H2O2, and the quenched PL intensity of PPESO3 was proportionally to the concentration of BPA in the range of 1-100 μmol/L with a detection limit of 4 × 10(-7) mol/L. The proposed method has been applied to detect BPA in eight food packaging samples with satisfactory results. The proposed method has the potential for the assay of BPA in food or food packaging samples. Copyright © 2015 Elsevier Ltd. All rights reserved.

  13. Polymers for electronic & photonic application

    CERN Document Server

    Wong, C P

    2013-01-01

    The most recent advances in the use of polymeric materials by the electronic industry can be found in Polymers for Electronic and Photonic Applications. This bookprovides in-depth coverage of photoresis for micro-lithography, microelectronic encapsulants and packaging, insulators, dielectrics for multichip packaging,electronic and photonic applications of polymeric materials, among many other topics. Intended for engineers and scientists who design, process, and manufacturemicroelectronic components, this book will also prove useful for hybrid and systems packaging managers who want to be info

  14. Applications of polymers for biomolecule immobilization in electrochemical biosensors

    International Nuclear Information System (INIS)

    Teles, F.R.R.; Fonseca, L.P.

    2008-01-01

    Polymers are becoming inseparable from biomolecule immobilization strategies and biosensor platforms. Their original role as electrical insulators has been progressively substituted by their electrical conductive abilities, which opens a new and broad scope of applications. In addition, recent advances in diagnostic chips and microfluidic systems, together with the requirements of mass-production technologies, have raised the need to replace glass by polymeric materials, which are more suitable for production through simple manufacturing processes. Conducting polymers (CPs), in particular, are especially amenable for electrochemical biosensor development for providing biomolecule immobilization and for rapid electron transfer. It is expected that the combination of known polymer substrates, but also new transducing and biocompatible interfaces, with nanobiotechnological structures, like nanoparticles, carbon nanotubes (CNTs) and nanoengineered 'smart' polymers, may generate composites with new and interesting properties, providing higher sensitivity and stability of the immobilized molecules, thus constituting the basis for new and improved analytical devices for biomedical and other applications. This review covers the state-of-the-art and main novelties about the use of polymers for immobilization of biomolecules in electrochemical biosensor platforms

  15. In-situ gelling polymers for biomedical applications

    CERN Document Server

    2015-01-01

    This book presents the research involving in situ gelling polymers and can be used as a guidebook for academics, industrialists and postgraduates interested in this area. This work summaries the academic contributions from the top authorities in the field and explore the fundamental principles of in situ gelling polymeric networks, along with examples of their major applications. This book aims to provide an up-to-date resource of in situ gelling polymer research.

  16. Quantum dot doped solid polymer electrolyte for device application

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Pramod K.; Kim, Kang Wook; Rhee, Hee-Woo [Department of Chemical and Biomolecular Engineering, Sogang University, Mapo-Gu, Seoul 121-742 (Korea)

    2009-06-15

    ZnS capped CdSe quantum dots embedded in PEO:KI:I{sub 2} polymer electrolyte matrix have been synthesized and characterized for dye sensitized solar cell (DSSC) application. The complex impedance spectroscopy shows enhance in ionic conductivity ({sigma}) due to charges provide by quantum dots (QD) while AFM affirm the uniform distribution of QD into polymer electrolyte matrix. Cyclic voltammetry revealed the possible interaction between polymer electrolyte, QD and iodide/iodine. The photovoltaic performances of the DSSC containing quantum dots doped polymer electrolyte was also found to improve. (author)

  17. Structural Variations to a Donor Polymer with Low Energy Losses

    KAUST Repository

    Bazan, Guillermo C; Yuan, Jianyu; Ran, Niva; Ford, Michael; Wang, Ming; Kumar, Ravva Mehesh; Mai, Cheng-Kang; Liu, Xiaofeng; Bredas, Jean-Luc; Nguyen, Thuc-Quyen Thai; Ma, Wanli

    2017-01-01

    Two regioregular narrow band gap conjugated polymers with a D’-A-D-A repeat unit architecture, namely PIFCF and PSFCF, were designed and synthesized. Both polymers contain strictly organized fluorobenzo[c][1,2,5]thiadiazole (FBT) orientations

  18. Polymers containing borane or carborane cage compounds and related applications

    Science.gov (United States)

    Bowen, III, Daniel E.; Eastwood, Eric A [Raymore, MO

    2012-06-05

    Polymers comprising residues of borane and/or carborane cage compound monomers having at least one polyalkoxy silyl substituent. Such polymers can further comprise one or more reactive matrices and/or co-monomers covalently bound with the cage compound monomer residues. Methods of making and applications for using such polymers are also disclosed.

  19. Spray-dried mucoadhesives for intravesical drug delivery using N-acetylcysteine- and glutathione-glycol chitosan conjugates.

    Science.gov (United States)

    Denora, Nunzio; Lopedota, Angela; Perrone, Mara; Laquintana, Valentino; Iacobazzi, Rosa M; Milella, Antonella; Fanizza, Elisabetta; Depalo, Nicoletta; Cutrignelli, Annalisa; Lopalco, Antonio; Franco, Massimo

    2016-10-01

    This work describes N-acetylcysteine (NAC)- and glutathione (GSH)-glycol chitosan (GC) polymer conjugates engineered as potential platform useful to formulate micro-(MP) and nano-(NP) particles via spray-drying techniques. These conjugates are mucoadhesive over the range of urine pH, 5.0-7.0, which makes them advantageous for intravesical drug delivery and treatment of local bladder diseases. NAC- and GSH-GC conjugates were generated with a synthetic approach optimizing reaction times and purification in order to minimize the oxidation of thiol groups. In this way, the resulting amount of free thiol groups immobilized per gram of NAC- and GSH-GC conjugates was 6.3 and 3.6mmol, respectively. These polymers were completely characterized by molecular weight, surface sulfur content, solubility at different pH values, substitution and swelling degree. Mucoadhesion properties were evaluated in artificial urine by turbidimetric and zeta (ζ)-potential measurements demonstrating good mucoadhesion properties, in particular for NAC-GC at pH 5.0. Starting from the thiolated polymers, MP and NP were prepared using both the Büchi B-191 and Nano Büchi B-90 spray dryers, respectively. The resulting two formulations were evaluated for yield, size, oxidation of thiol groups and ex-vivo mucoadhesion. The new spray drying technique provided NP of suitable size (polymers, avoiding thiolic oxidation during the formulation. MP with acceptable size produced by spray-dryer Büchi B-191 were compared with NP made with the apparatus Nano Büchi B-90. Copyright © 2016 Acta Materialia Inc. All rights reserved.

  20. Polymer Based Biosensors for Medical Applications

    DEFF Research Database (Denmark)

    Cherré, Solène; Rozlosnik, Noemi

    2015-01-01

    , environmental monitoring and food safety. The detected element varies from a single molecule (such as glucose), a biopolymer (such as DNA or a protein) to a whole organism (such as bacteria). Due to their easy use and possible miniaturization, biosensors have a high potential to come out of the lab...... and be available for use by everybody. To fulfil these purposes, polymers represent very appropriate materials. Many nano- and microfabrication methods for polymers are available, allowing a fast and cheap production of devices. This chapter will present the general concept of a biosensor in a first part......The objective of this chapter is to give an overview about the newest developments in biosensors made of polymers for medical applications. Biosensors are devices that can recognize and detect a target with high selectivity. They are widely used in many fields such as medical diagnostic...