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Sample records for stretchable polymer grating

  1. Stretchable supercapacitors based on highly stretchable ionic liquid incorporated polymer electrolyte

    Energy Technology Data Exchange (ETDEWEB)

    Tamilarasan, P.; Ramaprabhu, S., E-mail: ramp@iitm.ac.in

    2014-11-14

    Mechanical stability of electrolyte in all-solid-state supercapacitor attains immense attention as it addresses safety aspects. In this study, we have demonstrated, the fabrication of stretchable supercapacitor based on stretchable electrolyte and hydrogen exfoliated graphene electrode. We synthesized ionic liquid incorporated stretchable Poly(methyl methacrylate) electrolyte which plays dual role as electrolyte and stretchable support for electrode material. The molecular vibration studies show composite nature of the electrolyte. At least four-fold stretchability has been observed along with good ionic conductivity (0.78 mS cm{sup −1} at 28 °C) for this polymer electrolyte. This stretchable supercapacitor shows a low equivalent series resistance (16 Ω) due to the compatibility at electrode–electrolyte interface. The performance of the device has been determined under strain as well. - Highlights: • A stretchable supercapacitor has been fabricated using stretchable electrolyte. • Here ionic liquid incorporated polymer plays dual role as electrolyte and stretchable support. • The developed device shows low equivalent series resistance. • The device has specific capacitance of 83 F g{sup −1}, at the specific current of 2.67 A g{sup −1}. • The energy density and power density of 25.7 Wh kg{sup −1} and 35.2 kW kg{sup −1}, respectively.

  2. Plastic Deformation as a Means to Achieve Stretchable Polymer Semiconductors

    Science.gov (United States)

    O'Connor, Brendan

    Developing intrinsically stretchable semiconductors will seamlessly transition traditional devices into a stretchable platform. Polymer semiconductors are inherently soft materials due to the weak van der Waal intermolecular bonding allowing for flexible devices. However, these materials are not typically stretchable and when large strains are applied they either crack or plastically deform. Here, we study the use of repeated plastic deformation as a means of achieving stretchable films. In this talk, critical aspects of polymer semiconductor material selection, morphology and interface properties will be discussed that enable this approach of achieving stretchable films. We show that one can employ high performance donor-acceptor polymer semiconductors that are typically brittle through proper polymer blending to significantly increase ductility to achieve stretchable films. We demonstrate a polymer blend film that can be repeatedly deformed over 65%, while maintaining charge mobility consistently above 0.15 cm2/Vs. During the stretching process we show that the films follow a well-controlled repeated deformation pattern for over 100 stretching cycles.

  3. Intrinsically stretchable and healable semiconducting polymer for organic transistors.

    Science.gov (United States)

    Oh, Jin Young; Rondeau-Gagné, Simon; Chiu, Yu-Cheng; Chortos, Alex; Lissel, Franziska; Wang, Ging-Ji Nathan; Schroeder, Bob C; Kurosawa, Tadanori; Lopez, Jeffrey; Katsumata, Toru; Xu, Jie; Zhu, Chenxin; Gu, Xiaodan; Bae, Won-Gyu; Kim, Yeongin; Jin, Lihua; Chung, Jong Won; Tok, Jeffrey B-H; Bao, Zhenan

    2016-11-17

    Thin-film field-effect transistors are essential elements of stretchable electronic devices for wearable electronics. All of the materials and components of such transistors need to be stretchable and mechanically robust. Although there has been recent progress towards stretchable conductors, the realization of stretchable semiconductors has focused mainly on strain-accommodating engineering of materials, or blending of nanofibres or nanowires into elastomers. An alternative approach relies on using semiconductors that are intrinsically stretchable, so that they can be fabricated using standard processing methods. Molecular stretchability can be enhanced when conjugated polymers, containing modified side-chains and segmented backbones, are infused with more flexible molecular building blocks. Here we present a design concept for stretchable semiconducting polymers, which involves introducing chemical moieties to promote dynamic non-covalent crosslinking of the conjugated polymers. These non-covalent crosslinking moieties are able to undergo an energy dissipation mechanism through breakage of bonds when strain is applied, while retaining high charge transport abilities. As a result, our polymer is able to recover its high field-effect mobility performance (more than 1 square centimetre per volt per second) even after a hundred cycles at 100 per cent applied strain. Organic thin-film field-effect transistors fabricated from these materials exhibited mobility as high as 1.3 square centimetres per volt per second and a high on/off current ratio exceeding a million. The field-effect mobility remained as high as 1.12 square centimetres per volt per second at 100 per cent strain along the direction perpendicular to the strain. The field-effect mobility of damaged devices can be almost fully recovered after a solvent and thermal healing treatment. Finally, we successfully fabricated a skin-inspired stretchable organic transistor operating under deformations that might be

  4. Polymer optical fiber bragg grating sensors

    DEFF Research Database (Denmark)

    Stefani, Alessio; Yuan, Scott Wu; Andresen, Søren

    2010-01-01

    Fiber-optical accelerometers based on polymer optical fiber Bragg gratings are reported. We have written fiber Bragg gratings for 1550 nm and 850 nm operations, characterized their temperature and strain response, and tested their performance in a prototype accelerometer....

  5. Self-grafting carbon nanotubes on polymers for stretchable electronics

    Science.gov (United States)

    Morales, Piero; Moyanova, Slavianka; Pavone, Luigi; Fazi, Laura; Mirabile Gattia, Daniele; Rapone, Bruno; Gaglione, Anderson; Senesi, Roberto

    2018-06-01

    Elementary bidimensional circuitry made of single-wall carbon-nanotube-based conductors, self-grafted on different polymer films, is accomplished in an attempt to develop a simple technology for flexible and stretchable electronic devices. Unlike in other studies of polymer-carbon nanotube composites, no chemical functionalization of single-wall carbon nanotubes is necessary for stable grafting onto several polymeric surfaces, suggesting viable and cheap fabrication technologies for stretchable microdevices. Electrical characterization of both unstretched and strongly stretched conductors is provided, while an insight on the mechanisms of strong adhesion to the polymer is obtained by scanning electron microscopy of the surface composite. As a first example of technological application, the electrical functionality of a carbon-nanotube-based 6-sensor (electrode) grid was demonstrated by recording of subdural electrocorticograms in freely moving rats over approximately three months. The results are very promising and may serve as a basis for future work targeting clinical applications.

  6. Fabrication of Polymer Optical Fibre (POF Gratings

    Directory of Open Access Journals (Sweden)

    Yanhua Luo

    2017-03-01

    Full Text Available Gratings inscribed in polymer optical fibre (POF have attracted remarkable interest for many potential applications due to their distinctive properties. This paper overviews the current state of fabrication of POF gratings since their first demonstration in 1999. In particular we summarize and discuss POF materials, POF photosensitivity, techniques and issues of fabricating POF gratings, as well as various types of POF gratings.

  7. Holographic gratings in photorefractive polymers without external electric field

    DEFF Research Database (Denmark)

    Kukhtarev, N.; Lyuksyutov, S.; Buchhave, Preben

    1997-01-01

    Using anomalous large diffusion we report a recording of reflection type gratings in a PVK-based photorefractive polymer without any external electric field. The diffraction efficiency of the gratings was measured to be 7%. An efficient modulation of beams during two-beam coupling up to 12...

  8. Zeonex Microstructured Polymer Optical Fibre Bragg Grating Sensor

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Fasano, Andrea; Markos, Christos

    2016-01-01

    We fabricated an endlessly single mode and humidity insensitive Zeonex microstructured polymer optical fibre (mPOF) for fibre Bragg grating (FBG) temperature and strain sensors. We inscribed and characterise FBGs in Zeonex mPOF for the first time.......We fabricated an endlessly single mode and humidity insensitive Zeonex microstructured polymer optical fibre (mPOF) for fibre Bragg grating (FBG) temperature and strain sensors. We inscribed and characterise FBGs in Zeonex mPOF for the first time....

  9. Micropatterning of a stretchable conductive polymer using inkjet printing and agarose stamping

    DEFF Research Database (Denmark)

    Hansen, Thomas Steen; Hassager, Ole; Larsen, Niels Bent

    2007-01-01

    A highly conducting stretchable polymer material has been patterned using additive inkjet printing and by subtractive agarose stamping of a deactivation agent (hypochlorite). The material consisted of elastomeric polyurethane combined in an interpenetrating network with a conductive polymer, poly(3....... Inkjet printing of the material was only possible if a short-chain polyurethane was used as elastomer to overcome strain hardening at the neck of the droplets produced for printing. Reproducible line widths down to 200 μm could be achieved by inkjet printing. Both methods were used to fabricate test...

  10. Investigations on birefringence effects in polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Hu, Xiaolian; Saez-Rodriguez, D.; Bang, Ole

    2014-01-01

    Step-index polymer optical fiber Bragg gratings (POFBGs) and microstructured polymer optical fiber Bragg gratings (mPOFBGs) present several attractive features, especially for sensing purposes. In comparison to FBGs written in silica fibers, they are more sensitive to temperature and pressure...... because of the larger thermo-optic coefficient and smaller Young's modulus of polymer materials. (M)POFBGs are most often photowritten in poly(methylmethacrylate) (PMMA) materials using a continuous-wave 325 nm HeCd laser. For the first time to the best of our knowledge, we study photoinduced...... birefringence effects in (m)POFBGs. To achieve this, highly reflective gratings were inscribed with the phase mask technique. They were then monitored in transmission with polarized light. For this, (m)POF sections a few cm in length containing the gratings were glued to angled silica fibers. Polarization...

  11. Metal/Polymer Based Stretchable Antenna for Constant Frequency Far-Field Communication in Wearable Electronics

    KAUST Repository

    Hussain, Aftab M.; Ghaffar, Farhan A.; Park, Sung I.; Rogers, John A.; Shamim, Atif; Hussain, Muhammad Mustafa

    2015-01-01

    electronics which can physically stretch to absorb the strain associated with body movements. While research in stretchable electronics has started to gain momentum, a stretchable antenna which can perform far-field communications and can operate at constant

  12. 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.

  13. Humidity insensitive TOPAS polymer fiber Bragg grating sensor

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Khan, Lutul; Webb, David J.

    2011-01-01

    We report the first experimental demonstration of a humidity insensitive polymer optical fiber Bragg grating (FBG), as well as the first FBG recorded in a TOPAS polymer optical fiber in the important low loss 850nm spectral region. For the demonstration we have fabricated FBGs with resonance...... wavelength around 850 nm and 1550 nm in single-mode microstructured polymer optical fibers made of TOPAS and the conventional poly (methyl methacrylate) (PMMA). Characterization of the FBGs shows that the TOPAS FBG is more than 50 times less sensitive to humidity than the conventional PMMA FBG in both...... wavelength regimes. This makes the TOPAS FBG very appealing for sensing applications as it appears to solve the humidity sensitivity problem suffered by the PMMA FBG....

  14. Elastomeric polymer resonant waveguide grating based pressure sensor

    International Nuclear Information System (INIS)

    Song, Fuchuan; Xie, Antonio Jou; Seo, Sang-Woo

    2014-01-01

    In this paper, we demonstrate an elastomeric polymer resonant waveguide grating structure to be used as a pressure sensor. The applied pressure is measured by optical resonance spectrum peak shift. The sensitivity—as high as 86.74 pm psi −1 or 12.58 pm kPa −1 —has been experimentally obtained from a fabricated sensor. Potentially, the sensitivity of the demonstrated sensor can be tuned to different pressure ranges by the choices of elastic properties and layer thicknesses of the waveguide and cladding layers. The simulation results agree well with experimental results and indicate that the dominant effect on the sensor is the change of grating period when external pressure is applied. Based on the two-dimensional planar structure, the demonstrated sensor can be used to measure applied surface pressure optically, which has potential applications for optical ultrasound imaging and pressure wave detection/mapping

  15. Improved thermal and strain performance of annealed polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bache, Morten

    2011-01-01

    We report on a detailed study of the inscription and characterization of fiber Bragg gratings (FBGs) in commercial step index polymer optical fibers (POFs). Through the growth dynamics of the gratings, we identify the effect of UV-induced heating during the grating inscription. We found that FBGs...

  16. Embedding silica and polymer fibre Bragg gratings (FBG) in plastic 3D-printed sensing patches

    DEFF Research Database (Denmark)

    Zubel, Michal G.; Sugden, Kate; Webb, David J.

    2016-01-01

    This paper reports the first demonstration of a silica fibre Bragg grating (SOFBG) embedded in an FDM 3-D printed housing to yield a dual grating temperature-compensated strain sensor. We also report the first ever integration of polymer fibre Bragg grating (POFBG) within a 3-D printed sensing...

  17. Fibre Bragg Grating and Long Period Grating Sensors in Polymer Optical Fibres

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar

    mechanisms in polymer fibres using a CO2 laser. One is etching and the other one is perturbation of the microstructured region. After inscription of LPGs, the concept of a biocompatible distributed medical endoscope is presented, where an all-plastic LPG based device is produced. A transducer pod is made...... of applications and pushing the limits. The first part of the work focuses on the fabrication of FBGs in polymer optical fibres. FBGs are a periodic perturbation of the refractive index of the optical fibre core which act as a wavelength specific reflector. The fibres used are made of Polymethyl methacrylate....... In this system a high power CO2 laser is used for the inscription. An LPG is also a periodic perturbation of the guided core mode in fibre, but unlike FBG which reflects the core mode, the LPG couples the core mode to a cladding mode outside the core. We have shown that the LPG grating can be formed through two...

  18. Polymer Optical Fibre Bragg Grating Humidity Sensor at 100ºC

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Fasano, Andrea; Markos, Christos

    2016-01-01

    We have demonstrated a polymer optical fibre Bragg grating humidity sensor that can be operated up to 100ºC. The sensor has been fabricated from a polycarbonate (PC) microstructured polymer optical fibre Bragg grating (mPOFBG). PC mPOFBG gave a relative humidity (RH) sensitivity of 6.95±0.83 pm...

  19. Polymer-assisted metal deposition (PAMD): a full-solution strategy for flexible, stretchable, compressible, and wearable metal conductors.

    Science.gov (United States)

    Yu, You; Yan, Casey; Zheng, Zijian

    2014-08-20

    Metal interconnects, contacts, and electrodes are indispensable elements for most applications of flexible, stretchable, and wearable electronics. Current fabrication methods for these metal conductors are mainly based on conventional microfabrication procedures that have been migrated from Si semiconductor industries, which face significant challenges for organic-based compliant substrates. This Research News highlights a recently developed full-solution processing strategy, polymer-assisted metal deposition (PAMD), which is particularly suitable for the roll-to-roll, low-cost fabrication of high-performance compliant metal conductors (Cu, Ni, Ag, and Au) on a wide variety of organic substrates including plastics, elastomers, papers, and textiles. This paper presents i) the principles of PAMD, and how to use it for making ii) flexible, stretchable, and wearable conductive metal electrodes, iii) patterned metal interconnects, and d) 3D stretchable and compressible metal sponges. A critical perspective on this emerging strategy is also provided. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Metal/Polymer Based Stretchable Antenna for Constant Frequency Far-Field Communication in Wearable Electronics

    KAUST Repository

    Hussain, Aftab M.

    2015-10-06

    Body integrated wearable electronics can be used for advanced health monitoring, security, and wellness. Due to the complex, asymmetric surface of human body and atypical motion such as stretching in elbow, finger joints, wrist, knee, ankle, etc. electronics integrated to body need to be physically flexible, conforming, and stretchable. In that context, state-of-the-art electronics are unusable due to their bulky, rigid, and brittle framework. Therefore, it is critical to develop stretchable electronics which can physically stretch to absorb the strain associated with body movements. While research in stretchable electronics has started to gain momentum, a stretchable antenna which can perform far-field communications and can operate at constant frequency, such that physical shape modulation will not compromise its functionality, is yet to be realized. Here, a stretchable antenna is shown, using a low-cost metal (copper) on flexible polymeric platform, which functions at constant frequency of 2.45 GHz, for far-field applications. While mounted on a stretchable fabric worn by a human subject, the fabricated antenna communicated at a distance of 80 m with 1.25 mW transmitted power. This work shows an integration strategy from compact antenna design to its practical experimentation for enhanced data communication capability in future generation wearable electronics.

  1. Extremely stretchable thermosensitive hydrogels by introducing slide-ring polyrotaxane cross-linkers and ionic groups into the polymer network

    Science.gov (United States)

    Bin Imran, Abu; Esaki, Kenta; Gotoh, Hiroaki; Seki, Takahiro; Ito, Kohzo; Sakai, Yasuhiro; Takeoka, Yukikazu

    2014-01-01

    Stimuli-sensitive hydrogels changing their volumes and shapes in response to various stimulations have potential applications in multiple fields. However, these hydrogels have not yet been commercialized due to some problems that need to be overcome. One of the most significant problems is that conventional stimuli-sensitive hydrogels are usually brittle. Here we prepare extremely stretchable thermosensitive hydrogels with good toughness by using polyrotaxane derivatives composed of α-cyclodextrin and polyethylene glycol as cross-linkers and introducing ionic groups into the polymer network. The ionic groups help the polyrotaxane cross-linkers to become well extended in the polymer network. The resulting hydrogels are surprisingly stretchable and tough because the cross-linked α-cyclodextrin molecules can move along the polyethylene glycol chains. In addition, the polyrotaxane cross-linkers can be used with a variety of vinyl monomers; the mechanical properties of the wide variety of polymer gels can be improved by using these cross-linkers. PMID:25296246

  2. Super-stretchable metallic interconnects on polymer with a linear strain of up to 100%

    Energy Technology Data Exchange (ETDEWEB)

    Arafat, Yeasir; Dutta, Indranath; Panat, Rahul, E-mail: Rahul.panat@wsu.edu [School of Mechanical and Materials Engineering, Washington State University, Pullman, Washington 99163 (United States)

    2015-08-24

    Metal interconnects in flexible and wearable devices are heterogeneous metal-polymer systems that are expected to sustain large deformation without failure. The principal strategy to make strain tolerant interconnect lines on flexible substrates has comprised of creating serpentine structures of metal films with either in-plane or out-of-plane waves, using porous substrates, or using highly ductile materials such as gold. The wavy and helical serpentine patterns preclude high-density packing of interconnect lines on devices, while ductile materials such as Au are cost prohibitive for real world applications. Ductile copper films can be stretched if bonded to the substrate, but show high level of cracking beyond few tens of % strain. In this paper, we demonstrate a material system consisting of Indium metal film over an elastomer (PDMS) with a discontinuous Cr layer such that the metal interconnect can be stretched to extremely high linear strain (up to 100%) without any visible cracks. Such linear strain in metal interconnects exceeds that reported in literature and is obtained without the use of any geometrical manipulations or porous substrates. Systematic experimentation is carried out to explain the mechanisms that allow the Indium film to sustain the high strain level without failure. The islands forming the discontinuous Cr layer are shown to move apart from each other during stretching without delamination, providing strong adhesion to the Indium film while accommodating the large strain in the system. The Indium film is shown to form surface wrinkles upon release from the large strain, confirming its strong adhesion to PDMS. A model is proposed based upon the observations that can explain the high level of stretch-ability of the Indium metal film over the PDMS substrate.

  3. Faithful replication of grating patterns in polymer through electrohydrodynamic instabilities

    International Nuclear Information System (INIS)

    Li, H; Yu, W; Wang, T; Zhang, H; Cao, Y; Abraham, E; Desmulliez, M P Y

    2014-01-01

    Electrohydrodynamic instability patterning (EHDIP) as an alternative patterning method has attracted a great deal of attention over the past decade. This article demonstrates the faithful transfer of patterns with a high aspect ratio onto a polymer film via electrohydrodynamic instabilities for a given patterned grating mask. We perform a simple mathematical analysis to determine the influence of process parameters on the pressure difference ▵P. Through numerical simulation, it is demonstrated that thick films subject to large electric fields are essential to realize this faithful replication. In particular, the influence of the material properties of the polymer on pattern replication is discussed in detail. It is found that, to achieve the smaller periodic patterns with a higher resolution, film with a larger value of the dielectric constant and smaller value of the surface tension should be chosen. In addition, an ideal replication of the mask pattern with a short evolution time is possible by reducing the viscosity of the polymer liquid. Finally, the experiments of the pattern replication with and without defects are demonstrated to compare with the numerical simulation results. It is found that experiments are in good agreement with the simulation results and prove that the numerical simulation method provides an effective way to predict faithful replication. (paper)

  4. Imaging of Volume Phase Gratings in a Photosensitive Polymer, Recorded in Transmission and Reflection Geometry

    Directory of Open Access Journals (Sweden)

    Tina Sabel

    2014-02-01

    Full Text Available Volume phase gratings, recorded in a photosensitive polymer by two-beam interference exposure, are studied by means of optical microscopy. Transmission gratings and reflection gratings, with periods in the order of 10 μm down to 130 nm, were investigated. Mapping of holograms by means of imaging in sectional view is introduced to study reflection-type gratings, evading the resolution limit of classical optical microscopy. In addition, this technique is applied to examine so-called parasitic gratings, arising from interference from the incident reference beam and the reflected signal beam. The appearance and possible avoidance of such unintentionally recorded secondary structures is discussed.

  5. Competition between deformability and charge transport in semiconducting polymers for flexible and stretchable electronics

    Energy Technology Data Exchange (ETDEWEB)

    Printz, Adam D.; Lipomi, Darren J., E-mail: dlipomi@ucsd.edu [Department of NanoEngineering, University of California, San Diego, 9500 Gilman Drive, Mail Code 0448, La Jolla, California 92093-0448 (United States)

    2016-06-15

    enough to disrupt charge transport pathways. The aim of this review is to provide a bridge between the fields interested in electronic properties and mechanical properties of conjugated polymers. We provide a high-level introduction to some of the important electronic and mechanical properties and measurement techniques for organic electronic devices, demonstrate an apparent competition between good electronic performance and mechanical deformability, and highlight potential strategies for overcoming this undesirable competition. A marriage of these two fields would allow for rational design of materials for applications requiring large-area, low-cost, printable devices that are ultra-flexible or stretchable, such as organic photovoltaic devices and wearable, conformable, or implantable sensors.

  6. Competition between deformability and charge transport in semiconducting polymers for flexible and stretchable electronics

    International Nuclear Information System (INIS)

    Printz, Adam D.; Lipomi, Darren J.

    2016-01-01

    enough to disrupt charge transport pathways. The aim of this review is to provide a bridge between the fields interested in electronic properties and mechanical properties of conjugated polymers. We provide a high-level introduction to some of the important electronic and mechanical properties and measurement techniques for organic electronic devices, demonstrate an apparent competition between good electronic performance and mechanical deformability, and highlight potential strategies for overcoming this undesirable competition. A marriage of these two fields would allow for rational design of materials for applications requiring large-area, low-cost, printable devices that are ultra-flexible or stretchable, such as organic photovoltaic devices and wearable, conformable, or implantable sensors.

  7. Novel thermal annealing methodology for permanent tuning polymer optical fiber Bragg gratings to longer wavelengths.

    Science.gov (United States)

    Pospori, A; Marques, C A F; Sagias, G; Lamela-Rivera, H; Webb, D J

    2018-01-22

    The Bragg wavelength of a polymer optical fiber Bragg grating can be permanently shifted by utilizing the thermal annealing method. In all the reported fiber annealing cases, the authors were able to tune the Bragg wavelength only to shorter wavelengths, since the polymer fiber shrinks in length during the annealing process. This article demonstrates a novel thermal annealing methodology for permanently tuning polymer optical fiber Bragg gratings to any desirable spectral position, including longer wavelengths. Stretching the polymer optical fiber during the annealing process, the period of Bragg grating, which is directly related with the Bragg wavelength, can become permanently longer. The methodology presented in this article can be used to multiplex polymer optical fiber Bragg gratings at any desirable spectral position utilizing only one phase-mask for their photo-inscription, reducing thus their fabrication cost in an industrial setting.

  8. Moiré phase-shifted fiber Bragg gratings in polymer optical fibers

    Science.gov (United States)

    Min, Rui; Marques, Carlos; Bang, Ole; Ortega, Beatriz

    2018-03-01

    We demonstrate a simple way to fabricate phase-shifted fiber Bragg grating in polymer optical fibers as a narrowband transmission filter for a variety of applications at telecom wavelengths. The filters have been fabricated by overlapping two uniform fiber Bragg gratings with slightly different periods to create a Moiré grating with only two pulses (one pulse is 15 ns) of UV power. Experimental characterization of the filter is provided under different conditions where the strain and temperature sensitivities were measured.

  9. Moiré phase-shifted fiber Bragg gratings in polymer optical fibers

    DEFF Research Database (Denmark)

    Min, Rui; Marques, Carlos; Bang, Ole

    2018-01-01

    We demonstrate a simple way to fabricate phase-shifted fiber Bragg grating in polymer optical fibers as a narrowband transmission filter for a variety of applications at telecom wavelengths. The filters have been fabricated by overlapping two uniform fiber Bragg gratings with slightly different...

  10. Fiber-optical accelerometers based on polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bang, Ole

    2010-01-01

    Fiber-optical accelerometers based on polymer optical fiber Bragg gratings (FBGs) are reported. We have written 3mm FBGs for 1550nm operation, characterized their temperature and strain response, and tested their performance in a prototype accelerometer.......Fiber-optical accelerometers based on polymer optical fiber Bragg gratings (FBGs) are reported. We have written 3mm FBGs for 1550nm operation, characterized their temperature and strain response, and tested their performance in a prototype accelerometer....

  11. Molecular Engineering for Mechanically Resilient and Stretchable Electronic Polymers and Composites

    Science.gov (United States)

    2016-06-08

    The public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing...study, etc. 3. DATES COVERED. Indicate the time during which the work was performed and the report was written, e.g., Jun 1997 - Jun 1998; 1-10 Jun...describing its operation and its special place in the depths of medieval sadism, which proved that the stretchability of Homo sapiens is not reversible

  12. Polymer coated fiber Bragg grating thermometry for microwave hyperthermia.

    Science.gov (United States)

    Saxena, Indu Fiesler; Hui, Kaleo; Astrahan, Melvin

    2010-09-01

    Measuring tissue temperature distribution during electromagnetically induced hyperthermia (HT) is challenging. High resistance thermistors with nonmetallic leads have been used successfully in commercial HT systems for about three decades. The single 1 mm thick temperature sensing element is mechanically moved to measure tissue temperature distributions. By employing a single thermometry probe containing a fixed linear sensor array temperature, distributions during therapy can be measured with greater ease. While the first attempts to use fiber Bragg grating (FBG) technology to obtain multiple temperature points along a single fiber have been reported, improvement in the detection system's stability were needed for clinical applications. The FBG temperature sensing system described here has a very high temporal stability detection system and an order of magnitude faster readout than commercial systems. It is shown to be suitable for multiple point fiber thermometry during microwave hyperthermia when compared to conventional mechanically scanning probe HT thermometry. A polymer coated fiber Bragg grating (PFBG) technology is described that provides a number of FBG thermometry locations along the length of a single optical fiber. The PFBG probe developed is tested under simulated microwave hyperthermia treatment to a tissue equivalent phantom. Two temperature probes, the multiple PFBG sensor and the Bowman probe, placed symmetrically with respect to a microwave antenna in a tissue phantom are subjected to microwave hyperthermia. Measurements are made at start of HT and 85 min later, when a 6 degrees C increase in temperature is registered by both probes, as is typical in clinical HT therapy. The optical fiber multipoint thermometry probe performs highly stable, real-time thermometry updating each multipoint thermometry scan over a 5 cm length every 2 s. Bowman probe measurements are acquired simultaneously for comparison. In addition, the PFBG sensor's detection

  13. Bragg Grating Based Sensors in Microstructured Polymer Optical Fibers: Accelerometers and Microphones

    DEFF Research Database (Denmark)

    Stefani, Alessio

    With the growing interest towards fiber Bragg grating sensors and the growing ability in manufacturing polymer optical fibers, the development of polymer fiber Bragg sensors has catched the attention of industries with the goal of developing high performance sensors. This thesis presents...... and in microstructured fibers made of PMMA and TOPAS is reported. The gratings have been written at both 1550 nm, to take advantage of components made for telecommunications, and 850 nm, to exploit the lower loss of polymers and the fast acquisition electronics at this wavelength. A technique for writing multiplexed...

  14. Polarization-Independent Electrically Tunable Holographic Polymer Dispersed Liquid Crystals Grating Doped with Chiral Molecules

    Directory of Open Access Journals (Sweden)

    Hui LI

    2017-08-01

    Full Text Available This study proposes a holographic grating made of polymer dispersed liquid crystal (PDLC, with a small amount of chiral molecules doped into PDLC material. The major advantage of this grating is that it is independent of light polarization. This characteristic was verified by applying the interference beam intensity of a He-Cd laser at 150 mW/cm2, with an incidence angle between the two interference beams of 24°, for an irradiation curing duration of 120 s. The observed periodic structure of the grating is consistent with the theoretical value. As chiral molecules are doped, nematic-LC experiences a phase-change in the grating. However, the electro-optical features are only slightly affected. This proposed grating has greatly potential in 3D imaging because of its polarization-independent feature.DOI: http://dx.doi.org/10.5755/j01.ms.23.2.16312

  15. Direct Writing of Fiber Bragg Grating in Microstructured Polymer Optical Fiber

    DEFF Research Database (Denmark)

    Stefani, Alessio; Stecher, Matthias; Town, G. E.

    2012-01-01

    We report point-by-point laser direct writing of a 1520-nm fiber Bragg grating in a microstructured polymer optical fiber (mPOF). The mPOF is specially designed such that the microstructure does not obstruct the writing beam when properly aligned. A fourth-order grating is inscribed in the m......POF with only a 2.5-s writing time....

  16. GISAXS study of Au-coated light-induced polymer gratings

    Energy Technology Data Exchange (ETDEWEB)

    Castro-Colin, M., E-mail: miguel.castro-colin@bruker.com; Korolkov, D. [Bruker AXS, Rheinbrueckenstr. 49, 76187 Karlsruhe (Germany); Yadavalli, N. S. [Nanostructured Materials Lab, The University of Georgia, 30602 Athens, Georgia (United States); Mayorova, M.; Kentzinger, M. [Research Center Juelich, 52425 Juelich (Germany); Santer, S. [Institute of Physics and Astronomy, University of Potsdam, 14476 Potsdam (Germany)

    2015-07-23

    Surface Relief Gratings (SRGs) are inscribed in the Au-coated azobenzene containing photosensitive polymer films on a glass substrate. The structures consist of micrometer-period sinusoidal patterns of sub-micron amplitudes, formed by photo-isomerization and molecular reorientation processes in the polymer film during exposure to the light interference pattern that drove the formation of a SRG; the precursor is a stack sequence of Au, polymer, and glass. The SRG structures were exposed in GISAXS geometry to high-intensity X-ray radiation from a liquid Ga source (0.134 nm). Scattered photons were registered by a 2D detector, and their intensity distribution enabled us to characterize the structures. Analysis of the 2D patterns yielded information about the pitch of the gratings as well as the thickness of the films forming the gratings. The GISAXS experiments were carried out at the Research Center Juelich.

  17. Effect of degree of crosslinking and polymerization of 3D printable polymer/ionic liquid composites on performance of stretchable piezoresistive sensors

    Science.gov (United States)

    Lee, Jeongwoo; Faruk Emon, Md Omar; Vatani, Morteza; Choi, Jae-Won

    2017-03-01

    Ionic liquid (IL)/polymer composites (1-ethyl-3-methyl-imidazolium tetrafluoroborate (EMIMBF4)/2-[[(butylamino)carbonyl]oxy]ethyl acrylate (BACOEA)) were fabricated to use as sensing materials for stretchable piezoresistive tactile sensors. The detectability of the IL/polymer composites was enhanced because the ionic transport properties of EMIMBF4 in the composites were improved by the synergic actions between the coordinate sites generated by the local motion of BACOEA chain segments under enough activation energy. The performance of the piezoresistive sensors was investigated with the degree of crosslinking and polymerization of the IL/polymer composites. As the compressive strain was increased, the distance between two electrodes decreased, and the motion of polymer chains and IL occurred, resulting in a decrease in the electrical resistance of the sensors. We have confirmed that the sensitivity of the sensors are affected by the degree of crosslink and polymerization of the IL/polymer composites. In addition, all of the materials (skins, sensing material, and electrode) used in this study are photo-curable, and thus the stretchable piezoresistive tactile sensors can be successfully fabricated by 3D printing.

  18. Bragg gratings inscription at 1550 nm in photosensitive step-index polymer optical fiber

    Science.gov (United States)

    Hu, X.; Kinet, D.; Chah, K.; Mégret, Patrice; Caucheteur, C.

    2013-05-01

    In this paper, we report photo-inscription of uniform Bragg gratings in Trans-4-stilbenemethanol-doped photosensitive step-index polymer optical fiber characterized by a core diameter of 8.2 μm. Single-mode gratings were produced at ~1550 nm by the phase mask technique with a Helium-Cadmium emitting at 325 nm with an average power of 30 mW. The grating growth was monitored during the manufacturing process, showing that the reflected band is blue shifted by a few hundreds of picometers. Finally, the gratings were characterized in temperature in the range 25 - 50 °C. Their sensitivity has been computed equal to - 47 pm/°C.

  19. Polarization and switching properties of holographic polymer-dispersed liquid-crystal gratings. I. Theoretical model

    Science.gov (United States)

    Sutherland, Richard L.

    2002-12-01

    Polarization properties and electro-optical switching behavior of holographic polymer-dispersed liquid-crystal (HPDLC) reflection and transmission gratings are studied. A theoretical model is developed that combines anisotropic coupled-wave theory with an elongated liquid-crystal-droplet switching model and includes the effects of a statistical orientational distribution of droplet-symmetry axes. Angle- and polarization-dependent switching behaviors of HPDLC gratings are elucidated, and the effects on dynamic range are described. A new type of electro-optical switching not seen in ordinary polymer-dispersed liquid crystals, to the best of the author's knowledge, is presented and given a physical interpretation. The model provides valuable insight to the physics of these gratings and can be applied to the design of HPDLC holographic optical elements.

  20. Thermal and chemical treatment of polymer optical fiber Bragg grating sensors for enhanced mechanical sensitivity

    DEFF Research Database (Denmark)

    Pospori, Andreas; Marques, C. A. F.; Saez-Rodriguez, D.

    2017-01-01

    An investigation of the thermal annealing effects on the strain, stress, and force sensitivities of polymer optical fiber Bragg grating sensors is performed. We demonstrate for the first time that the fiber annealing can enhance both stress and force sensitivities of Bragg grating sensors......, with the possible cause being the molecular relaxation of the polymer when fiber is raised above the β-transition temperature. A simple, cost-effective, but well controlled method for fiber annealing is also presented in this work. In addition, the effects of chemical etching on the strain, stress, and force...... sensitivities have been investigated. Results show that fiber etching too can increase the force sensitivity, and it can also affect the strain and stress sensitivities of the Bragg grating sensors....

  1. Thermal and chemical treatment of polymer optical fiber Bragg grating sensors for enhanced mechanical sensitivity

    Science.gov (United States)

    Pospori, A.; Marques, C. A. F.; Sáez-Rodríguez, D.; Nielsen, K.; Bang, O.; Webb, D. J.

    2017-07-01

    An investigation of the thermal annealing effects on the strain, stress, and force sensitivities of polymer optical fiber Bragg grating sensors is performed. We demonstrate for the first time that the fiber annealing can enhance both stress and force sensitivities of Bragg grating sensors, with the possible cause being the molecular relaxation of the polymer when fiber is raised above the β -transition temperature. A simple, cost-effective, but well controlled method for fiber annealing is also presented in this work. In addition, the effects of chemical etching on the strain, stress, and force sensitivities have been investigated. Results show that fiber etching too can increase the force sensitivity, and it can also affect the strain and stress sensitivities of the Bragg grating sensors.

  2. Polymer waveguide Bragg grating Fabry–Perot filter using a nanoimprinting technique

    International Nuclear Information System (INIS)

    Binfeng, Yun; Guohua, Hu; Yiping, Cui

    2014-01-01

    A narrow band waveguide Fabry–Perot filter at 1550 nm, which is composed of two polymer waveguide Bragg gratings as reflectors, is presented. By using conventional lithography, a low-loss polymer channel waveguide was fabricated, and the submicron Bragg grating structure was transferred onto the waveguide surface using a nanoimprinting technique. The transmission spectrum of the device was measured, and the results show that there is a very narrow transmission peak, with a 3 dB bandwidth of 0.011 nm in the 0.38 nm rejection band of the waveguide Bragg grating. A quality factor of Q ≈ 1.41 × 10 5 is achieved. The insertion loss and the extinction ratio of the Fabry–Perot filter are about −12.5 dB and 17 dB, respectively. In addition, the measured transmission spectrum is in excellent accordance with the numerical simulation. (paper)

  3. A stretchable polymer-carbon nanotube composite electrode for flexible lithium-ion batteries: porosity engineering by controlled phase separation

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Hojun; Yoo, Jung-Keun; Jung, Yeon Sik [Department of Materials Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon (Korea, Republic of); Park, Jong-Hyun [Material R and D Department, LG Display Co., Ltd., Paju-si, Gyeonggi-do (Korea, Republic of); Kim, Jin Ho [Icheon Branch, Korea Institute of Ceramic Engineering and Technology, Icheon-si, Gyeonggi-do (Korea, Republic of); Kang, Kisuk [Department of Materials Science and Engineering, Seoul National University, Seoul (Korea, Republic of)

    2012-08-15

    Flexible energy-storage devices have attracted growing attention with the fast development of bendable electronic systems. However, it still remains a challenge to find reliable electrode materials with both high mechanical flexibility/toughness and excellent electron and lithium-ion conductivity. This paper reports the fabrication and characterization of highly porous, stretchable, and conductive polymer nanocomposites embedded with carbon nanotubes (CNTs) for application in flexible lithium-ion batteries. The systematic optimization of the porous morphology is performed by controllably inducing the phase separation of polymethylmethacrylate (PMMA) in polydimethylsiloxane (PDMS) and removing PMMA, in order to generate well-controlled pore networks. It is demonstrated that the porous CNT-embedded PDMS nanocomposites are capable of good electrochemical performance with mechanical flexibility, suggesting these nanocomposites could be outstanding anode candidates for use in flexible lithium-ion batteries. The optimization of the pore size and the volume fraction provides higher capacity by nearly seven-fold compared to a nonporous nanocomposite. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  4. Temperature insensitive hysteresis free highly sensitive polymer optical fiber Bragg grating humidity sensor

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Nielsen, Kristian; Stefani, Alessio

    2016-01-01

    The effect of humidity on annealing of poly (methyl methacrylate) (PMMA) based microstructured polymer optical fiber Bragg gratings (mPOFBGs) and the resulting humidity responsivity are investigated. Typically annealing of PMMA POFs is done in an oven without humidity control around 80°C...

  5. Fast Inscription of Long Period Gratings in Microstructured Polymer Optical Fibers

    DEFF Research Database (Denmark)

    Min, Rui; Marques, Carlos; Nielsen, Kristian

    2018-01-01

    We demonstrate 20 dB long period grating (LPG) fast inscription in microstructured polymer optical fibers (mPOFs) using a point-by-point technique obtaining an LPG total length of 25 mm. Two 248 nm UV laser pulses of 15 ns duration have been employed for every inscription point, which means a time...

  6. 3-D printed sensing patches with embedded polymer optical fibre Bragg gratings

    DEFF Research Database (Denmark)

    Zubel, Michal G.; Sugden, Kate; Saez-Rodriguez, D.

    2016-01-01

    The first demonstration of a polymer optical fibre Bragg grating (POFBG) embedded in a 3-D printed structure is reported. Its cyclic strain performance and temperature characteristics are examined and discussed. The sensing patch has a repeatable strain sensitivity of 0.38 pm/mu epsilon. Its...

  7. Blazed vector gratings fabricated using photosensitive polymer liquid crystals and control of polarization diffraction

    Science.gov (United States)

    Ono, Hiroshi; Kuzuwata, Mitsuru; Sasaki, Tomoyuki; Noda, Kohei; Kawatsuki, Nobuhiro

    2014-03-01

    The blazed vector grating possessing antisymmetric distributions of the birefringence were fabricated by exposing the line-focused linearly polarized ultraviolet light on the photosensitive polymer liquid crystals. The polarization states of the diffraction beams can be highly and widely controlled by designing the blazed structures, and the diffraction properties were well-explained by Jones calculus.

  8. Recent developments of Bragg gratings in PMMA and TOPAS polymer optical fibers

    DEFF Research Database (Denmark)

    Webb, David; Kyriacos, Kalli; Carroll, Karen

    temperature to the glass transition temperature, and this permanent change is affected by the thermal history of the gratings. We also report the first FBG inscription in microstructured polymer optical fibres fabricated from Topas. This material is fully polymerised and has a very low moisture absorption...

  9. Stretchable, Weavable Coiled Carbon Nanotube/MnO2/Polymer Fiber Solid-State Supercapacitors

    Science.gov (United States)

    Choi, Changsoon; Kim, Shi Hyeong; Sim, Hyeon Jun; Lee, Jae Ah; Choi, A Young; Kim, Youn Tae; Lepró, Xavier; Spinks, Geoffrey M.; Baughman, Ray H.; Kim, Seon Jeong

    2015-01-01

    Fiber and yarn supercapacitors that are elastomerically deformable without performance loss are sought for such applications as power sources for wearable electronics, micro-devices, and implantable medical devices. Previously reported yarn and fiber supercapacitors are expensive to fabricate, difficult to upscale, or non-stretchable, which limits possible use. The elastomeric electrodes of the present solid-state supercapacitors are made by using giant inserted twist to coil a nylon sewing thread that is helically wrapped with a carbon nanotube sheet, and then electrochemically depositing pseudocapacitive MnO2 nanofibers. These solid-state supercapacitors decrease capacitance by less than 15% when reversibly stretched by 150% in the fiber direction, and largely retain capacitance while being cyclically stretched during charge and discharge. The maximum linear and areal capacitances (based on active materials) and areal energy storage and power densities (based on overall supercapacitor dimensions) are high (5.4 mF/cm, 40.9 mF/cm2, 2.6 μWh/cm2 and 66.9 μW/cm2, respectively), despite the engineered superelasticity of the fiber supercapacitor. Retention of supercapacitor performance during large strain (50%) elastic deformation is demonstrated for supercapacitors incorporated into the wristband of a glove. PMID:25797351

  10. Stretchable, weavable coiled carbon nanotube/MnO2/polymer fiber solid-state supercapacitors.

    Science.gov (United States)

    Choi, Changsoon; Kim, Shi Hyeong; Sim, Hyeon Jun; Lee, Jae Ah; Choi, A Young; Kim, Youn Tae; Lepró, Xavier; Spinks, Geoffrey M; Baughman, Ray H; Kim, Seon Jeong

    2015-03-23

    Fiber and yarn supercapacitors that are elastomerically deformable without performance loss are sought for such applications as power sources for wearable electronics, micro-devices, and implantable medical devices. Previously reported yarn and fiber supercapacitors are expensive to fabricate, difficult to upscale, or non-stretchable, which limits possible use. The elastomeric electrodes of the present solid-state supercapacitors are made by using giant inserted twist to coil a nylon sewing thread that is helically wrapped with a carbon nanotube sheet, and then electrochemically depositing pseudocapacitive MnO2 nanofibers. These solid-state supercapacitors decrease capacitance by less than 15% when reversibly stretched by 150% in the fiber direction, and largely retain capacitance while being cyclically stretched during charge and discharge. The maximum linear and areal capacitances (based on active materials) and areal energy storage and power densities (based on overall supercapacitor dimensions) are high (5.4 mF/cm, 40.9 mF/cm(2), 2.6 μWh/cm(2) and 66.9 μW/cm(2), respectively), despite the engineered superelasticity of the fiber supercapacitor. Retention of supercapacitor performance during large strain (50%) elastic deformation is demonstrated for supercapacitors incorporated into the wristband of a glove.

  11. Laser formation of Bragg gratings in polymer nanocomposite materials

    Energy Technology Data Exchange (ETDEWEB)

    Nazarov, M M; Khaydukov, K V; Sokolov, V I; Khaydukov, E V [Institute on Laser and Information Technologies, Russian Academy of Sciences, Shatura, Moscow Region (Russian Federation)

    2016-01-31

    The method investigated in this work is based on the laser-induced, spatially inhomogeneous polymerisation of nanocomposite materials and allows control over the motion and structuring of nanoparticles. The mechanisms of nanoparticle concentration redistribution in the process of radical photopolymerisation are studied. It is shown that under the condition of spatially inhomogeneous illumination of a nanocomposite material, nanoparticles are diffused from the illuminated areas into the dark fields. Diffraction gratings with a thickness of 8 μm and a refractive index modulation of 1 × 10{sup -2} are written in an OCM-2 monomer impregnated by silicon nanoparticles. The gratings may be used in the development of narrowband filters, in holographic information recording and as dispersion elements in integrated optical devices. (interaction of laser radiation with matter. laser plasma)

  12. Simultaneous measurement of temperature and humidity with microstructured polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Pedersen, Jens Kristian Mølgaard; Fasano, Andrea

    2017-01-01

    A microstructured polymer optical fiber (mPOF) Bragg grating sensor system for the simultaneous measurement of temperature and relative humidity (RH) has been developed and characterized. The sensing head is based on two in-line fiber Bragg gratings recorded in a mPOF. The sensor system has a root...... mean square deviation of 1.04 % RH and 0.8 °C in the range 10 to 90% RH and 20 to 80 °C. The proposed sensor system is easy to fabricate, cheap and compact....

  13. Bragg Grating Inscription With Low Pulse Energy in Doped Microstructured Polymer Optical Fibers

    DEFF Research Database (Denmark)

    Min, Rui; Ortega, Beatriz; Nielsen, Kristian

    2018-01-01

    in the POFs without high pulse energy (mJ level) at 248-nm wavelength, which reduces maintenance costs. Furthermore, we can consider it as a solution to increase the lifetime of the laser system without high energy still allowing fast and efficient production of the FBGs for sensing applications.......We demonstrate that fiber Bragg gratings (FBGs) can be written in a doped polymer optical fiber (POF) in a low ultraviolet (UV) pulse energy regime (60Jpulse) using a 248-nm krypton fluoride excimer laser system. The total energy density per inscription necessary to obtain Bragg gratings is between...

  14. Polymer optical fiber Bragg grating inscription with a single UV laser pulse

    DEFF Research Database (Denmark)

    Pospori, Andreas; Marques, A.T.; Bang, Ole

    2017-01-01

    We experimentally demonstrate the first polymer optical fiber Bragg grating inscribed with only one krypton fluoride laser pulse. The device has been recorded in a single-mode poly(methyl methacrylate) optical fiber, with a core doped with benzyl dimethyl ketal for photosensitivity enhancement. One...... laser pulse with a duration of 15 ns, which provide energy density of 974 mJ/cm2, is adequate to introduce a refractive index change of 0.74×10-4 in the fiber core. After the exposure, the reflectivity of the grating increases for a few minutes following a second order exponential saturation...

  15. High-quality phase-shifted Bragg grating sensor inscribed with only one laser pulse in a polymer optical fiber

    DEFF Research Database (Denmark)

    Marques, C. A. F.; Pospori, A.; Pereira, L.

    2017-01-01

    We present the first phase-shifted polymer optical fiber Bragg grating sensor inscribed with only one KrF laser pulse. The phase shift defect was created directly during the grating inscription process by placing a very narrow blocking aperture, in the center of the UV beam. One laser pulse...

  16. Technology for Polymer Optical Fiber Bragg Grating Fabrication and Interrogation

    DEFF Research Database (Denmark)

    Ganziy, Denis

    The aim of this project is to develop a new, high-quality interrogator for FBG sensor systems, which combines high performance with costeffectiveness. The work includes the fields of optical system design, signal processing, and algorithm investigation. We present an efficient and fast peak...... analyze and investigate errors and drawbacks, which are typical for spectrometer-based interrogators: undersampling, grating internal reflection, photo response nonuniformity, pixel crosstalk and temperature and long term drift. We propose a novel type of multichannel Digital Micromirror Device (DMD......) based interrogator, where the linear detector is replaced with a commercially available DMD, which leads to cost reduction and better performance. Original optical design, which utilizes advantages of a retro-reflect optical scheme, has been developed in Zemax. We test the presented interrogator...

  17. Tunable Polymer Fiber Bragg Grating (FBG) Inscription: Fabrication of Dual-FBG Temperature Compensated Polymer Optical Fiber Strain Sensors

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bang, Ole

    2012-01-01

    We demonstrate stable wavelength tunable inscription of polymer optical fiber Bragg gratings (FBGs). By straining the fiber during FBG inscription, we linearly tune the center wavelength over 7 nm with less than 1% strain. Above 1% strain, the tuning curve saturates and we show a maximum tuning...... of 12 nm with 2.25% strain. We use this inscription method to fabricate a dual-FBG strain sensor in a poly (methyl methacrylate) single-mode microstructured polymer optical fiber and demonstrate temperature compensated strain sensing around 850 nm....

  18. Surface relief gratings: experiments, physical scenarios, and photoinduced (anomalous) dynamics of functionalized polymer chains

    Science.gov (United States)

    Mitus, A. C.; Radosz, W.; Wysoczanski, T.; Pawlik, G.

    2017-10-01

    Surface Relief Gratings (SRG) were demonstrated experimentally more than 20 years ago. Despite many years of research efforts the underlying physical mechanisms remain unclear. In this paper we present a short overview of the main concepts related to SRG - photofluidization and its counterpart, the orientational approach - based on a seminal paper by Saphiannikova et al. Next, we summarize the derivation of the cos2 θ potential, following the lines of recent paper of this group. Those results validate the generic Monte Carlo model for the photoinduced build-up of the density and SRG gratings in a model polymer matrix functionalized with azo-dyes, presented in another part of the paper. The characterization of the photoinduced motion of polymer chains, based on our recent paper, is briefly discussed in the last part of the paper. This discussion offers a sound insight into the mechanisms responsible for inscription of SRG as well as for single functionalized nanoparticle studies.

  19. Humidity insensitive step-index polymer optical fibre Bragg grating sensors

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Fasano, Andrea; Stefani, Alessio

    2015-01-01

    We have fabricated and characterised a humidity insensitive step index(SI) polymer optical fibre(POF) Bragg grating sensors. The fibre was made based on the injection molding technique, which is an efficient method for fast, flexible and cost effective preparation of the fibre preform. The fabric...... poly-methyl-methacrylate (PMMA) based SIPOFs. The fibre has a minimum loss of similar to 6dB/m at 770nm....

  20. Improved response time of laser etched polymer optical fiber Bragg grating humidity sensor

    OpenAIRE

    Zhang, Wei; Chen, Xianfeng; Liu, Chen; Lu, Yuanfu; Cardoso, Marcos; Webb, David J.

    2015-01-01

    The humidity sensor made of polymer optical fiber Bragg grating (POFBG) responds to the water content change in fiber induced by the change of environmental condition. The response time strongly depends on fiber size as the water change is a diffusion process. The ultra short laser pulses have been providing an effective micro fabrication method to achieve spatial localized modification in materials. In this work we used the excimer laser to create different microstructures (slot, D-shape) in...

  1. Investigation of the in-solution relaxation of polymer optical fibre Bragg gratings

    DEFF Research Database (Denmark)

    Fasano, Andrea; Woyessa, Getinet; Janting, Jakob

    2016-01-01

    We investigate the response of PMMA microstructured polymer optical fibre Bragg gratings whenimmersed in methanol/water solutions. Overall we observe a permanent blue-shift in Bragg gratingwavelength after solvent evaporation. The main contribution in the resonance wavelength shift probably...... arisesfrom a permanent change in the size of the fibre, as already reported for high-temperature annealing ofpolymer optical fibres. As a consequence of the solution concentration dependence of the glass transitiontemperature of polymers, different methanol/water solutions lead to various degrees of frozen...

  2. The effect of humidity on annealing of polymer optical fibre bragg gratings

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Nielsen, Kristian; Bang, Ole

    2015-01-01

    The effect of humidity on annealing of PMMA based microstructured polymer optical fiber (mPOF) Bragg gratings is studied. Polymer optical fibers (POFs) are annealed in order to release stress formed during the fabrication process. Un-annealed fibers will have high hysteresis and low sensitivity...... to humidity, particularly when operated at high temperature. Typically annealing of PMMA POFs is done at 80oC in an oven with no humidity control and therefor at low humidity. The response to humidity of PMMA FBGs annealed at different levels of humidity at the same temperature has also been studied. PMMA...

  3. Modeling fiber Bragg grating device networks in photomechanical polymer optical fibers

    Science.gov (United States)

    Lanska, Joseph T.; Kuzyk, Mark G.; Sullivan, Dennis M.

    2015-09-01

    We report on the modeling of fiber Bragg grating (FBG) networks in poly(methyl methacrylate) (PMMA) polymer fibers doped with azo dyes. Our target is the development of Photomechanical Optical Devices (PODs), comprised of two FBGs in series, separated by a Fabry-Perot cavity of photomechanical material. PODs exhibit photomechanical multi-stability, with the capacity to access multiple length states for a fixed input intensity when a mechanical shock is applied. Using finite-difference time-domain (FDTD) numerical methods, we modeled the photomechanical response of both Fabry-Perot and Bragg-type PODs in a single polymer optical fiber. The polymer fiber was modeled as an instantaneous Kerr-type nonlinear χ(3) material. Our model correctly predicts the essential optical features of FBGs as well as the photomechanical multi-stability of nonlinear Fabry-Perot cavity-based PODs. Networks of PODs may provide a framework for smart shape-shifting materials and fast optical computation where the decision process is distributed over the entire network. In addition, a POD can act as memory, and its response can depend on input history. Our models inform and will accelerate targeted development of novel Bragg grating-based polymer fiber device networks for a variety of applications in optical computing and smart materials.

  4. Highly reflective Bragg gratings in slightly etched step-index polymer optical fiber.

    Science.gov (United States)

    Hu, Xuehao; Pun, Chi-Fung Jeff; Tam, Hwa-Yaw; Mégret, Patrice; Caucheteur, Christophe

    2014-07-28

    During the past few years, a strong progress has been made in the photo-writing of fiber Bragg gratings (FBGs) in polymer optical fibers (POFs), animated by the constant wish to enhance the grating reflectivity and improve the sensing performances. In this paper, we report the photo-inscription of highly reflective gratings in step-index POFs, obtained thanks to a slight etching of the cladding. We demonstrate that a cladding diameter decrease of ~12% is an ideal trade-off to produce highly reflective gratings with enhanced axial strain sensitivity, while keeping almost intact their mechanical resistance. For this, we make use of Trans-4-stilbenemethanol-doped photosensitive step-index poly(methyl methacrylate) (PMMA) POFs. FBGs are inscribed at ~1550 nm by the scanning phase mask technique in POFs of different external diameters. Reflectivity reaching 97% is achieved for 6 mm long FBGs, compared to 25% for non-etched POFs. We also report that a cladding decrease enhances the FBG axial tension while keeping unchanged temperature and surrounding refractive index sensitivities. Finally and for the first time, a measurement is conducted in transmission with polarized light, showing that a photo-induced birefringence of 7 × 10(-6) is generated (one order of magnitude higher than the intrinsic fiber birefringence), which is similar to the one generated in silica fiber using ultra-violet laser.

  5. VUV treatment combined with mechanical strain of stretchable polymer foils resulting in cell alignment

    Energy Technology Data Exchange (ETDEWEB)

    Barb, R.-A. [Institute of Applied Physics, Johannes Kepler University Linz (Austria); Magnus, B. [Innovacell Biotechnologie AG, Innsbruck (Austria); Innerbichler, S. [Innerbichler GmbH, Breitenbach am Inn (Austria); Greunz, T. [CDL-MS-MACH, Johannes Kepler University Linz (Austria); Wiesbauer, M. [Institute of Applied Physics, Johannes Kepler University Linz (Austria); Marksteiner, R. [Innovacell Biotechnologie AG, Innsbruck (Austria); Stifter, D. [CDL-MS-MACH, Johannes Kepler University Linz (Austria); Heitz, J., E-mail: johannes.heitz@jku.at [Institute of Applied Physics, Johannes Kepler University Linz (Austria)

    2015-01-15

    Highlights: • Elastic polyurethane (PU) foils were exposed to the vacuum-UV in reactive atmosphere. • The photomodification resulted in improved cytocompatibilty. • Parallel microgrooves formed on the irradiated PU surfaces after strong elongation. • Cells seeded onto microgrooves aligned their shapes in the direction of the grooves. • Elongation occurred also for cells on PU subjected to cyclic mechanical stretching. - Abstract: Cell-alignment along a defined direction can have a direct effect on the cell functionality and differentiation. Oriented micro- or nanotopographic structures on cell culture substrates can induce cell-alignment. Surface chemistry, wettability, and stiffness of the substrate are also important material features as they strongly influence the cell–substrate interactions. For improved bio-compatibility, highly elastic polyurethane (PU) foils were exposed to the vacuum-UV (VUV) light of a Xe{sub 2}{sup *} excimer lamp at 172 nm in a nitrogen containing atmosphere (N{sub 2} or NH{sub 3}). The irradiation resulted in a change in the chemical surface composition. Additionally, the formation of regular parallel microgrooves was observed on the irradiated surfaces after strong uni-axial deformation (i.e., more than about 50% strain) of the photo-modified PU foils. Cell seeding experiments demonstrated that the VUV modified polymer foils strongly enhance cell adhesion and proliferation. Cells seeded onto microgrooves aligned their shapes and elongated in the direction of the grooves. A similar effect was observed for cells seeded on photo-modified PU foils subjected to cyclic mechanical stretching at lower strain levels (i.e., typically 10% strain) without groove-formation. The cells had also here an elongated shape, however they not always align in a defined direction relative to the stretching.

  6. Solution-Mediated Annealing of Polymer Optical Fiber Bragg Gratings at Room Temperature

    DEFF Research Database (Denmark)

    Fasano, Andrea; Woyessa, Getinet; Janting, Jakob

    2017-01-01

    In this letter, we investigate the response of poly(methylmethacrylate) (PMMA) microstructured polymer optical fiber Bragg gratings (POFBGs) after immersion inmethanol/water solutions at room temperature. As the glass transition temperature of solution-equilibrated PMMA differs from the one...... of solvent-free PMMA, different concentrations of methanol and water lead to various degrees of frozen-in stress relaxation in the fiber. After solvent evaporation, we observe a permanent blue-shift in the grating resonance wavelength. The main contribution in the resonance wavelength shift arises from...... a permanent change in the size of the fiber. The results are compared with conventional annealing. The proposed methodology is cost-effective as it does not require a climate chamber. Furthermore, it enables an easy-to-control tuning of the resonance wavelength of POFBGs....

  7. Aviation Fuel Gauging Sensor Utilizing Multiple Diaphragm Sensors Incorporating Polymer Optical Fiber Bragg Gratings

    DEFF Research Database (Denmark)

    Marques, C. A. F.; Pospori, A.; Saez-Rodriguez, D.

    2016-01-01

    A high-performance fuel gauging sensor is described that uses five diaphragm-based pressure sensors, which are monitored using a linear array of polymer optical fiber Bragg gratings. The sensors were initially characterized using water, revealing a sensitivity of 98 pm/cm for four of the sensors...... of sensors manufactured with a polyurethane-based diaphragm showed no measurable deterioration over a three month period immersed in fuel. These sensors exhibited a sensitivity of 39 pm/cm, which is less than the silicone rubber devices due to the stiffer nature of the polyurethane material used....

  8. Annealing and etching effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A.F.; Sáez-Rodríguez, D.

    2017-01-01

    Thermal annealing and chemical etching effects on the strain and stress sensitivity of polymer optical fibre based sensors are investigated. Bragg grating sensors have been photo-inscribed in PMMA optical fibre and their strain and stress sensitivity has been characterised before and after any...... annealing or etching process. The annealing and etching processes have been tried in different sequence in order to investigate their impact on the sensor's performance. Results show with high confidence that fibre annealing can improve both strain and stress sensitivities. The fibre etching can also...... provide stress sensitivity enhancement, however the strain sensitivity changes seems to be random....

  9. Fiber Bragg grating sensor based on cantilever structure embedded in polymer 3D printed material

    Science.gov (United States)

    Lima, Rita; Tavares, R.; Silva, S. O.; Abreu, P.; Restivo, Maria T.; Frazão, O.

    2017-04-01

    A cantilever structure in 3D printed based on a fiber Bragg grating (FBG) sensor embedded in polymer material is proposed. The FBG sensor was embedded in 3D printed coating and was tested under three physical parameters: displacement, temperature and vibration. The sensor was tested in displacement in two different regions of the cantilever, namely, on its midpoint and end point. The maximum displacement sensitivity achieved was (3 +/- 0.1) pm/mm for end point displacement, and a temperature sensitivity of (30 +/- 1) pm/°C was also attained. In the case of vibration measurements it was possible to obtain a 10.23Hz-low frequency oscillation.

  10. Bragg grating writing in PMMA microstructured polymer optical fibers in less than 7 minutes

    DEFF Research Database (Denmark)

    Bundalo, Ivan-Lazar; Nielsen, Kristian; Markos, Christos

    2014-01-01

    We demonstrate fiber Bragg grating (FBG) writing in PMMA microstructured Polymer Optical Fibers (mPOFs) using UV Phase Mask technique with writing times shorter than 10 min. The shortest writing time was 6 minutes and 50 seconds and the longest writing time was 8 min and 50 sec. The FBGs were...... written in a 125 x00B5;m PMMA mPOF having 3-rings of holes, the reflection peaks were centred at 632.6 nm and have a reflectivity as high as 26 dB. We also demonstrate how the writing dynamics depends on the intensity of the writing beam....

  11. Charging suppression in focused-ion beam fabrication of visible subwavelength dielectric grating reflector using electron conducting polymer

    KAUST Repository

    Alias, Mohd Sharizal; Liao, Hsien-Yu; Ng, Tien Khee; Ooi, Boon S.

    2015-01-01

    Nanoscale periodic patterning on insulating materials using focused-ion beam (FIB) is challenging because of charging effect, which causes pattern distortion and resolution degradation. In this paper, the authors used a charging suppression scheme using electron conducting polymer for the implementation of FIB patterned dielectric subwavelength grating (SWG) reflector. Prior to the FIB patterning, the authors numerically designed the optimal structure and the fabrication tolerance for all grating parameters (period, grating thickness, fill-factor, and low refractive index layer thickness) using the rigorous-coupled wave analysis computation. Then, the authors performed the FIB patterning on the dielectric SWG reflector spin-coated with electron conducting polymer for the anticharging purpose. They also performed similar patterning using thin conductive film anticharging scheme (30 nm Cr coating) for comparison. Their results show that the electron conducting polymer anticharging scheme effectively suppressing the charging effect during the FIB patterning of dielectric SWG reflector. The fabricated grating exhibited nanoscale precision, high uniformity and contrast, constant patterning, and complied with fabrication tolerance for all grating parameters across the entire patterned area. Utilization of electron conducting polymer leads to a simpler anticharging scheme with high precision and uniformity for FIB patterning on insulator materials.

  12. Charging suppression in focused-ion beam fabrication of visible subwavelength dielectric grating reflector using electron conducting polymer

    KAUST Repository

    Alias, Mohd Sharizal

    2015-08-19

    Nanoscale periodic patterning on insulating materials using focused-ion beam (FIB) is challenging because of charging effect, which causes pattern distortion and resolution degradation. In this paper, the authors used a charging suppression scheme using electron conducting polymer for the implementation of FIB patterned dielectric subwavelength grating (SWG) reflector. Prior to the FIB patterning, the authors numerically designed the optimal structure and the fabrication tolerance for all grating parameters (period, grating thickness, fill-factor, and low refractive index layer thickness) using the rigorous-coupled wave analysis computation. Then, the authors performed the FIB patterning on the dielectric SWG reflector spin-coated with electron conducting polymer for the anticharging purpose. They also performed similar patterning using thin conductive film anticharging scheme (30 nm Cr coating) for comparison. Their results show that the electron conducting polymer anticharging scheme effectively suppressing the charging effect during the FIB patterning of dielectric SWG reflector. The fabricated grating exhibited nanoscale precision, high uniformity and contrast, constant patterning, and complied with fabrication tolerance for all grating parameters across the entire patterned area. Utilization of electron conducting polymer leads to a simpler anticharging scheme with high precision and uniformity for FIB patterning on insulator materials.

  13. A high throughput liquid crystal light shutter for unpolarized light using polymer polarization gratings

    Science.gov (United States)

    Komanduri, Ravi K.; Lawler, Kris F.; Escuti, Michael J.

    2011-05-01

    We report on a broadband, diffractive, light shutter with the ability to modulate unpolarized light. This polarizer-free approach employs a conventional liquid crystal (LC) switch, combined with broadband Polarization Gratings (PGs) formed with polymer LC materials. The thin-film PGs act as diffractive polarizing beam-splitters, while the LC switch operates on both orthogonal polarization states simultaneously. As an initial experimental proof-of- concept for unpolarized light with +/-7° aperture, we utilize a commercial twisted-nematic LC switch and our own polymer PGs to achieve a peak transmittance of 80% and peak contrast ratio of 230:1. We characterize the optoelectronic performance, discuss the limitations, and evaluate its use in potential nonmechanical shutter applications (imaging and non-imaging).

  14. Electroactive subwavelength gratings (ESWGs) from conjugated polymers for color and intensity modulation

    Science.gov (United States)

    Bhuvana, Thiruvelu; Kim, Byeonggwan; Yang, Xu; Shin, Haijin; Kim, Eunkyoung

    2012-05-01

    Subwavelength gratings with electroactive polymers such as poly(3-hexylthiophene) (P3HT) and poly(3,4-propylenedioxythiophene-phenylene) (P(ProDOT-Ph)) controlled the color intensity for various visible colors of diffracted light in a single device. Under the illumination of a white light, at a fixed angle of incidence, the color intensity of the diffracted light was reversibly switched from the maximum value down to 15% (85% decrease) by applying -2 to 2 V due to electrochemical (EC) reaction. All spectral colors including red, green, and blue were generated by changing the angle of incidence, and the intensity of each color was modulated electrochemically at a single EC device. With electroactive subwavelength gratings (ESWGs) of P3HT, the maximum modulation of the color intensity was observed in the red-yellow quadrant in the CIE color plot, whereas for the ESWGs of P(ProDOT-Ph), the maximum modulation of the color intensity was observed in the yellow-green and green-blue quadrants. Both ESWGs showed a memory effect, keeping their color and intensity even after power was turned off for longer than 40 hours.Subwavelength gratings with electroactive polymers such as poly(3-hexylthiophene) (P3HT) and poly(3,4-propylenedioxythiophene-phenylene) (P(ProDOT-Ph)) controlled the color intensity for various visible colors of diffracted light in a single device. Under the illumination of a white light, at a fixed angle of incidence, the color intensity of the diffracted light was reversibly switched from the maximum value down to 15% (85% decrease) by applying -2 to 2 V due to electrochemical (EC) reaction. All spectral colors including red, green, and blue were generated by changing the angle of incidence, and the intensity of each color was modulated electrochemically at a single EC device. With electroactive subwavelength gratings (ESWGs) of P3HT, the maximum modulation of the color intensity was observed in the red-yellow quadrant in the CIE color plot, whereas for the

  15. Stretchable electronics

    CERN Document Server

    Someya, Takao

    2012-01-01

    With its comprehensive coverage this handbook and ready reference brings together some of the most outstanding scientists in the field to lay down the undisputed knowledge on how to make electronics stretchable.As such, it focuses on gathering and evaluating the materials, designs, models and technologies that enable the fabrication of fully elastic electronic devices which can sustain high strain. Furthermore, it provides a review of those specific applications that directly benefit from highly compliant electronics, including transistors, photonic devices and sensors. In addition to stre

  16. Stretchable antenna for wearable electronics

    KAUST Repository

    Hussain, Muhammad Mustafa

    2017-04-13

    Various examples are provided for stretchable antennas that can be used for applications such as wearable electronics. In one example, a stretchable antenna includes a flexible support structure including a lateral spring section having a proximal end and at a distal end; a metallic antenna disposed on at least a portion of the lateral spring section, the metallic antenna extending along the lateral spring section from the proximal end; and a metallic feed coupled to the metallic antenna at the proximal end of the lateral spring section. In another example, a method includes patterning a polymer layer disposed on a substrate to define a lateral spring section; disposing a metal layer on at least a portion of the lateral spring section, the metal layer forming an antenna extending along the portion of the lateral spring section; and releasing the polymer layer and the metal layer from the substrate.

  17. Fabrication and characterization of polycarbonate microstructured polymer optical fibers for high-temperature-resistant fiber Bragg grating strain sensors

    DEFF Research Database (Denmark)

    Fasano, Andrea; Woyessa, Getinet; Stajanca, Pavol

    2016-01-01

    Here we present the fabrication of a solid-core microstructured polymer optical fiber (mPOF) made of polycarbonate (PC), and report the first experimental demonstration of a fiber Bragg grating (FBG) written in a PC optical fiber. The PC used in this work has a glass transition temperature of 145°C...

  18. Strain Measurement Using Embedded Fiber Bragg Grating Sensors Inside an Anchored Carbon Fiber Polymer Reinforcement Prestressing Rod for Structural Monitoring

    DEFF Research Database (Denmark)

    Kerrouche, Abdelfateh; Boyle, William J.O.; Sun, Tong

    2009-01-01

    Results are reported from a study carried out using a series of Bragg grating based optical fiber sensors written into a very short length (60mm) optical fiber net work and integrated into carbon fiber polymer reinforcement (CFPR) rod. Such rods are used as reinforcements in concrete structures...

  19. Zeonex microstructured polymer optical fiber: fabrication friendly fibers for high temperature and humidity insensitive Bragg grating sensing

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Fasano, Andrea; Markos, Christos

    2017-01-01

    In the quest of finding the ideal polymer optical fiber (POF) for Bragg grating sensing, we have fabricated and characterized an endlessly single mode microstructured POF (mPOF). This fiber is made from cyclo-olefin homopolymer Zeonex grade 480R which has a very high glass transition temperature...

  20. Stretchable piezoelectric nanocomposite generator.

    Science.gov (United States)

    Park, Kwi-Il; Jeong, Chang Kyu; Kim, Na Kyung; Lee, Keon Jae

    2016-01-01

    Piezoelectric energy conversion that generate electric energy from ambient mechanical and vibrational movements is promising energy harvesting technology because it can use more accessible energy resources than other renewable natural energy. In particular, flexible and stretchable piezoelectric energy harvesters which can harvest the tiny biomechanical motions inside human body into electricity properly facilitate not only the self-powered energy system for flexible and wearable electronics but also sensitive piezoelectric sensors for motion detectors and in vivo diagnosis kits. Since the piezoelectric ZnO nanowires (NWs)-based energy harvesters (nanogenerators) were proposed in 2006, many researchers have attempted the nanogenerator by using the various fabrication process such as nanowire growth, electrospinning, and transfer techniques with piezoelectric materials including polyvinylidene fluoride (PVDF) polymer and perovskite ceramics. In 2012, the composite-based nanogenerators were developed using simple, low-cost, and scalable methods to overcome the significant issues with previously-reported energy harvester, such as insufficient output performance and size limitation. This review paper provides a brief overview of flexible and stretchable piezoelectric nanocomposite generator for realizing the self-powered energy system with development history, power performance, and applications.

  1. Selective vancomycin detection using optical fibre long period gratings functionalised with molecularly imprinted polymer nanoparticles.

    Science.gov (United States)

    Korposh, Sergiy; Chianella, Iva; Guerreiro, Antonio; Caygill, Sarah; Piletsky, Sergey; James, Stephen W; Tatam, Ralph P

    2014-05-07

    An optical fibre long period grating (LPG) sensor modified with molecularly imprinted polymer nanoparticles (nanoMIPs) for the specific detection of antibiotics is presented. The operation of the sensor is based on the measurement of changes in refractive index induced by the interaction of nanoMIPs deposited onto the cladding of the LPG with free vancomycin (VA). The binding of nanoMIPs to vancomycin was characterised by a binding constant of 4.3 ± 0.1 × 10(-8) M. The lowest concentration of analyte measured by the fibre sensor was 10 nM. In addition, the sensor exhibited selectivity, as much smaller responses were obtained for high concentrations (∼700 μM) of other commonly prescribed antibiotics such as amoxicillin, bleomycin and gentamicin. In addition, the response of the sensor was characterised in a complex matrix, porcine plasma, spiked with 10 μM of VA.

  2. Monitoring static shape memory polymers using a fiber Bragg grating as a vector-bending sensor

    Science.gov (United States)

    Li, Peng; Yan, Zhijun; Zhou, Kaiming; Zhang, Lin; Leng, Jinsong

    2013-01-01

    We propose and demonstrate a technique for monitoring the recovery deformation of the shape-memory polymers (SMP) using a surface-attached fiber Bragg grating (FBG) as a vector-bending sensor. The proposed sensing scheme could monitor the pure bending deformation for the SMP sample. When the SMP sample undergoes concave or convex bending, the resonance wavelength of the FBG will have red-shift or blue-shift according to the tensile or compressive stress gradient along the FBG. As the results show, the bending sensitivity is around 4.07 nm/cm-1. The experimental results clearly indicate that the deformation of such an SMP sample can be effectively monitored by the attached FBG not just for the bending curvature but also the bending direction.

  3. Fiber Bragg grating sensor for simultaneous measurement of temperature and force using polymer open loop

    Science.gov (United States)

    Huang, Yonglin; Zhang, Shiyan

    2014-07-01

    A fiber Bragg grating (FBG) sensor for simultaneous measurement of temperature and force is proposed and demonstrated. Where a part of uniform FBG (about one half length of an FBG) is attached on the polymer open loop, the FBG is divided into two parts which has an equal length. So the two parts can be regarded as two FBGs. Because of the difference of the Young's modulus and the thermal expansion coefficients for two parts of the FBG, the two Bragg reflection wavelengths are shift when the temperature and force are applied on the sensor. Simultaneous measurement of temperature and force is demonstrated experimentally. The experimental results show that the linear response to temperature and force are achieved. The value of applied temperature and force can be obtained from the two Bragg wavelength shift via the coefficient matrix. This study provides a simple and economical method to measure temperature and force simultaneously.

  4. Advances on Polymer Optical Fiber Gratings Using a KrF Pulsed Laser System Operating at 248 nm

    Directory of Open Access Journals (Sweden)

    Carlos A. F. Marques

    2018-03-01

    Full Text Available This paper presents the achievements and progress made on the polymer optical fiber (POF gratings inscription in different types of Fiber Bragg Gratings (FBGs and long period gratings (LPGs. Since the first demonstration of POFBGs in 1999, significant progress has been made where the inscription times that were higher than 1 h have been reduced to 15 ns with the application of the krypton fluoride (KrF pulsed laser operating at 248 nm and thermal treatments such as the pre-annealing of fibers. In addition, the application of dopants such as benzyl dimethyl ketal (BDK has provided a significant decrease of the fiber inscription time. Furthermore, such improvements lead to the possibility of inscribing POF gratings in 850 nm and 600 nm, instead of only the 1550 nm region. The progress on the inscription of different types of polymer optical fiber Bragg gratings (POFBGs such as chirped POFBGs and phase-shifted POFBGs are also reported in this review.

  5. Study of thermal annealing effect on Bragg gratings photo-inscribed in step-index polymer optical fibers

    Science.gov (United States)

    Hu, X.; Kinet, D.; Mégret, P.; Caucheteur, C.

    2016-04-01

    In this paper, both non-annealed and annealed trans-4-stilbenemethanol-doped step-index polymer optical fibers were photo-inscribed using a 325 nm HeCd laser with two different beam power densities reaching the fiber core. In the high density regime where 637 mW/mm2 are used, the grating reflectivity is stable over time after the photo-writing process but the reflected spectrum is of limited quality, as the grating physical length is limited to 1.2 mm. To produce longer gratings exhibiting more interesting spectral features, the beam is enlarged to 6 mm, decreasing the power density to 127 mW/mm2. In this second regime, the grating reflectivity is not stable after the inscription process but tends to decay for both kinds of fibers. A fortunate property in this case results from the possibility to fully recover the initial reflectivity using a post-inscription thermal annealing, where the gratings are annealed at 80 °C during 2 days. The observed evolutions for both regimes are attributed to the behavior of the excited intermediate states between the excited singlet and the ground singlet state of trans- and cis-isomers as well as the temperature-dependent glassy polymer matrix.

  6. Transmittance enhancement of sapphires with antireflective subwavelength grating patterned UV polymer surface structures by soft lithography.

    Science.gov (United States)

    Lee, Soo Hyun; Leem, Jung Woo; Yu, Jae Su

    2013-12-02

    We report the total and diffuse transmission enhancement of sapphires with the ultraviolet curable SU8 polymer surface structures consisting of conical subwavelength gratings (SWGs) at one- and both-side surfaces for different periods. The SWGs patterns on the silicon templates were transferred into the SU8 polymer film surface on sapphires by a simple and cost-effective soft lithography technique. For the fabricated samples, the surface morphologies, wetting behaviors, and optical characteristics were investigated. For theoretical optical analysis, a rigorous coupled-wave analysis method was used. At a period of 350 nm, the sample with SWGs on SU8 film/sapphire exhibited a hydrophobic surface and higher total transmittance compared to the bare sapphire over a wide wavelength of 450-1000 nm. As the period of SWGs was increased, the low total transmittance region of < 85% was shifted towards the longer wavelengths and became broader while the diffuse transmittance was increased (i.e., larger haze ratio). For the samples with SWGs at both-side surfaces, the total and diffuse transmittance spectra were further enhanced compared to the samples with SWGs at one-side surface. The theoretical optical calculation results showed a similar trend to the experimentally measured data.

  7. Temperature sensing of micron scale polymer fibers using fiber Bragg gratings

    KAUST Repository

    Zhou, Jian

    2015-07-02

    Highly conductive polymer fibers are key components in the design of multifunctional textiles. Measuring the voltage/temperature relationships of these fibers is very challenging due to their very small diameters, making it impossible to rely on classical temperature sensing techniques. These fibers are also so fragile that they cannot withstand any perturbation from external measurement systems. We propose here, a non-contact temperature measurement technique based on fiber Bragg gratings (FBGs). The heat exchange is carefully controlled between the probed fibers and the sensing FBG by promoting radiation and convective heat transfer rather than conduction, which is known to be poorly controlled. We demonstrate our technique on a highly conductive Poly(3,4-ethylenedioxythiophene)/poly(styrenesulfonate) (PEDOT/PSS)-based fiber. A non-phenomenological model of the sensing system based on meaningful physical parameters is validated towards experimental observations. The technique reliably measures the temperature of the polymer fibers when subjected to electrical loading. © 2015 IOP Publishing Ltd.

  8. Creation of a microstructured polymer optical fiber with UV Bragg grating inscription for the detection of extensions at temperatures up to 125°C

    DEFF Research Database (Denmark)

    Fasano, Andrea; Woyessa, Getinet; Stajanca, Pavol

    2016-01-01

    We describe the fabrication of a polycarbonate (PC) micro-structured polymer optical fiber (mPOF) and the writing offiber Bragg gratings (FBGs) in it to enable strain and temperature measurements. We demonstrate the photosensitivity ofa dopant-free PC fiber by grating inscription using a UV laser...

  9. Fabrication of three-dimensional polymer quadratic nonlinear grating structures by layer-by-layer direct laser writing technique

    Science.gov (United States)

    Bich Do, Danh; Lin, Jian Hung; Diep Lai, Ngoc; Kan, Hung-Chih; Hsu, Chia Chen

    2011-08-01

    We demonstrate the fabrication of a three-dimensional (3D) polymer quadratic nonlinear (χ(2)) grating structure. By performing layer-by-layer direct laser writing (DLW) and spin-coating approaches, desired photobleached grating patterns were embedded in the guest--host dispersed-red-1/poly(methylmethacrylate) (DR1/PMMA) active layers of an active-passive alternative multilayer structure through photobleaching of DR1 molecules. Polyvinyl-alcohol and SU8 thin films were deposited between DR1/PMMA layers serving as a passive layer to separate DR1/PMMA active layers. After applying the corona electric field poling to the multilayer structure, nonbleached DR1 molecules in the active layers formed polar distribution, and a 3D χ(2) grating structure was obtained. The χ(2) grating structures at different DR1/PMMA nonlinear layers were mapped by laser scanning second harmonic (SH) microscopy, and no cross talk was observed between SH images obtained from neighboring nonlinear layers. The layer-by-layer DLW technique is favorable to fabricating hierarchical 3D polymer nonlinear structures for optoelectronic applications with flexible structural design.

  10. Life cycle strain monitoring in glass fibre reinforced polymer laminates using embedded fibre Bragg grating sensors from manufacturing to failure

    DEFF Research Database (Denmark)

    Nielsen, Michael Wenani; Schmidt, Jacob Wittrup; Høgh, Jacob Herold

    2013-01-01

    A holistic approach to strain monitoring in fibre-reinforced polymer composites is presented using embedded fibre Bragg grating sensors. Internal strains are monitored in unidirectional E-glass/epoxy laminate beams during vacuum infusion, curing, post-curing and subsequent loading in flexure until...... of the different cure temperatures and tool/part interfaces used. Substantial internal process-induced strains develop in the transverse fibre direction, which should be taken into consideration when designing fibre-reinforced polymer laminates. Flexure tests indicate no significant difference in the mechanical...

  11. Fiber-optical microphones and accelerometers based on polymer optical fiber Bragg gratings

    DEFF Research Database (Denmark)

    Yuan, Scott Wu; Stefani, Alessio; Bang, Ole

    2010-01-01

    Polymer optical fibers (POFs) are ideal for applications as the sensing element in fiber-optical microphones and accelerometers based on fiber Bragg gratings (FBGs) due to their reduced Young’s Modulus of 3.2GPa, compared to 72GPa of Silica. To maximize the sensitivity and the dynamic range...... of the device the outer diameter and the length of the sensing fiber segment should be as small as possible. To this end we have fabricated 3mm FBGs in single-mode step-index POFs of diameter 115 micron, using 325nm UV writing and a phase-mask technique. 6mm POF sections with FBGs in the center have been glued...... to standard Silica SMF28 fibers. These POF FBGs have been characterized in terms of temperature and strain to find operating regimes with no hysteresis. Commercial fast wavelength interrogators (KHz) are shown to be able to track the thin POF FBGs and they are finally applied in a prototype accelerometer...

  12. Waterproof stretchable optoelectronics

    Science.gov (United States)

    Rogers, John A.; Kim, Rak-Hwan; Kim, Dae-Hyeong; Kaplan, David L.; Omenetto, Fiorenzo G.

    2018-04-03

    Described herein are flexible and stretchable LED arrays and methods utilizing flexible and stretchable LED arrays. Assembly of flexible LED arrays alongside flexible plasmonic crystals is useful for construction of fluid monitors, permitting sensitive detection of fluid refractive index and composition. Co-integration of flexible LED arrays with flexible photodetector arrays is useful for construction of flexible proximity sensors. Application of stretchable LED arrays onto flexible threads as light emitting sutures provides novel means for performing radiation therapy on wounds.

  13. Development of a New Stretchable and Screen Printable Conductive Ink

    Science.gov (United States)

    Mohammed, Anwar A.

    Stretchable conductive ink is a key enabler for stretchable electronics. This thesis research focuses on the development of a new stretchable and screen printable conductive ink. After print and cure, this ink would be capable of being stretched by at least 500 cycles at 20% strain without increasing its resistance by more than 30 times the original resistance, while maintaining electrical and mechanical integrity. For a stretchable and screen-printable conductive ink, the correct morphology of the metal powder selected and the ability of the binder to be stretched after the sintering process, are both indispensable. This research has shown that a bi-modal mixture of fine and large-diameter silver flakes will improve stretchability. While the smaller flakes increase the conductivity and lower the sintering temperature, the larger flake particles promote ohmic connectivity during stretching. The bi-modal flake distribution increases connection points while enhancing packing density and lowering the thermal activation barrier. The polymer binder phase plays a crucial role in offering stretchability to the stretchable conductive inks. The silver flakes by themselves are not stretchable but they are contained within a stretchable binder system. The research demonstrates that commonly used printable ink binder when combined with large-chain polymers through a process known as 'elastomeric chain polymerization' will enable the conductive ink to become more stretchable. This research has shown that the new stretchable and screen printable silver conductive ink developed based upon the two insights mentioned above; (1) bi modal flakes to improve ohmic connectivity during stretching and (2) elastomeric chain polymerized binder system which could stretch even after the ink is sintered to the substrate, can exhibit an ink stretchability of at least 500 cycles at 20% strain while increasing the resistance by less than 30 times the original resistance. Wavy print patterns can

  14. Fast bragg grating inscription in PMMA polymer optical fibres: Impact of thermal pre-treatment of preforms

    DEFF Research Database (Denmark)

    Marques, Carlos A. F.; Pospori, Andreas; Demirci, Gökhan

    2017-01-01

    In this work, fibre Bragg gratings (FBGs) were inscribed in two different undoped poly- (methyl methacrylate) (PMMA) polymer optical fibres (POFs) using different types of UV lasers and their inscription times, temperature and strain sensitivities are investigated. The POF Bragg gratings (POFBGs......) were inscribed using two UV lasers: a continuous UV HeCd @325 nm laser and a pulsed UV KrF @248 nm laser. Two PMMA POFs are used in which the primary and secondary preforms (during the two-step drawing process) have a different thermal treatment. The PMMA POFs drawn in which the primary or secondary...... preform is not specifically pre-treated need longer inscription time than the fibres drawn where both preforms have been pre-annealed at 80 °C for 2 weeks. Using both UV lasers, for the latter fibre much less inscription time is needed compared to another homemade POF. The properties of a POF fabricated...

  15. Strong guided mode resonant local field enhanced visible harmonic generation in an azo-polymer resonant waveguide grating.

    Science.gov (United States)

    Lin, Jian Hung; Tseng, Chun-Yen; Lee, Ching-Ting; Young, Jeff F; Kan, Hung-Chih; Hsu, Chia Chen

    2014-02-10

    Guided mode resonance (GMR) enhanced second- and third-harmonic generation (SHG and THG) is demonstrated in an azo-polymer resonant waveguide grating (RWG), comprised of a poled azo-polymer layer on top of a textured SU8 substrate with a thin intervening layer of TiO2. Strong SHG and THG outputs are observed by matching either in-coming fundamental- or out-going harmonic-wavelength to the GMR wavelengths of the azo-polymer RWG. Without the azo-polymer coating, pure TiO2 RWGs, do not generate any detectable SHG using a fundamental beam peak intensity of 2 MW/cm(2). Without the textured TiO2 layer, a planar poled azo-polymer layer results in 3650 times less SHG than the full nonlinear RWG structure under identical excitation conditions. Rigorous coupled-wave analysis calculations confirm that this enhancement of the nonlinear conversion is due to strong local electric fields that are generated at the interfaces of the TiO2 and azo-polymer layers when the RWG is excited at resonant wavelengths associated with both SHG and THG conversion processes.

  16. Strain Measurement Using Embedded Fiber Bragg Grating Sensors Inside an Anchored Carbon Fiber Polymer Reinforcement Prestressing Rod for Structural Monitoring

    OpenAIRE

    Kerrouche, Abdelfateh; Boyle, William J.O.; Sun, Tong; Grattan, Kenneth T. V.; Schmidt, Jacob Wittrup; Täljsten, Björn

    2009-01-01

    Results are reported from a study carried out using a series of Bragg grating-based optical fiber sensors written into a very short length (60 mm) optical fiber network and integrated into carbon fiber polymer reinforcement (CFPR) rod. Such rods are used as reinforcements in concrete structures and in tests were subjected to strain through a series of cycles of pulling tests, with applied forces of up to 30 kN. The results show that effective strain measurements can be obtained from the diffe...

  17. Effects of pre-strain on the intrinsic pressure sensitivity of polymer optical fiber Bragg-gratings

    DEFF Research Database (Denmark)

    Pedersen, Jens Kristian Mølgaard; Woyessa, Getinet; Nielsen, Kristian

    2017-01-01

    We experimentally demonstrate a scheme for improving the intrinsic pressure sensitivity of fiber Bragg-gratings (FBGs) inscribed in polymer optical fibers by applying pre-strain in order to suppress the pressure induced mechanical contraction of the fiber. This contraction would otherwise...... contribute to a blueshift of the Brag-wavelength, counteracting the dominant redshift caused by the stress-optic effect, which effectively reduces the pressure sensitivity of the FBG. By applying this technique we are able to improve the sensitivity of the FBG from 2.8 pm/bar to 7.3 pm/bar. © (2017...

  18. Cascaded holographic polymer reflection grating filters for optical-code-division multiple-access applications.

    Science.gov (United States)

    Kostuk, Raymond K; Maeda, Wendi; Chen, Chia-Hung; Djordjevic, Ivan; Vasic, Bane

    2005-12-10

    We evaluate the use of edge-illuminated holographic Bragg filters formed in phenanthrenequinone-doped poly(methyl methacrylate) for optical-code-division multiple-access (OCDMA) coding and decoding applications. Experimental cascaded Bragg filters are formed to select two different wavelengths with a fixed distance between the gratings and are directly coupled to a fiber-measurement system. The configuration and tolerances of the cascaded gratings are shown to be practical for time-wavelength OCDMA applications.

  19. A packaged, low-cost, robust optical fiber strain sensor based on small cladding fiber sandwiched within periodic polymer grating.

    Science.gov (United States)

    Chiang, Chia-Chin; Li, Chein-Hsing

    2014-06-02

    In the present study, a novel packaged long-period fiber grating (PLPFG) strain sensor is first presented. The MEMS process was utilized to fabricate the packaged optical fiber strain sensor. The sensor structure consisted of etched optical fiber sandwiched between two layers of thick photoresist SU-8 3050 and then packaged with poly (dimethylsiloxane) (PDMS) polymer material to construct the PLPFG strain sensor. The PDMS packaging material was used to prevent the glue effect, wherein glue flows into the LPFG structure and reduces coupling strength, in the surface bonding process. Because the fiber grating was packaged with PDMS material, it was effectively protected and made robust. The resonance attenuation dip of PLPFG grows when it is loading. This study explored the size effect of the grating period and fiber diameter of PLPFG via tensile testing. The experimental results found that the best strain sensitivity of the PLPFG strain sensor was -0.0342 dB/με, and that an R2 value of 0.963 was reached.

  20. Stretchable and semitransparent conductive hybrid hydrogels for flexible supercapacitors.

    Science.gov (United States)

    Hao, Guang-Ping; Hippauf, Felix; Oschatz, Martin; Wisser, Florian M; Leifert, Annika; Nickel, Winfried; Mohamed-Noriega, Nasser; Zheng, Zhikun; Kaskel, Stefan

    2014-07-22

    Conductive polymers showing stretchable and transparent properties have received extensive attention due to their enormous potential in flexible electronic devices. Here, we demonstrate a facile and smart strategy for the preparation of structurally stretchable, electrically conductive, and optically semitransparent polyaniline-containing hybrid hydrogel networks as electrode, which show high-performances in supercapacitor application. Remarkably, the stability can extend up to 35,000 cycles at a high current density of 8 A/g, because of the combined structural advantages in terms of flexible polymer chains, highly interconnected pores, and excellent contact between the host and guest functional polymer phase.

  1. Single mode step-index polymer optical fiber for humidity insensitive high temperature fiber Bragg grating sensors

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Fasano, Andrea; Stefani, Alessio

    2016-01-01

    We have fabricated the first single-mode step-index and humidity insensitive polymer optical fiber operating in the 850 nm wavelength ranges. The step-index preform is fabricated using injection molding, which is an efficient method for cost effective, flexible and fast preparation of the fiber...... preform. The fabricated single-mode step-index (SI) polymer optical fiber (POF) has a 4.8µm core made from TOPAS grade 5013S-04 with a glass transition temperature of 134°C and a 150 µm cladding made from ZEONEX grade 480R with a glass transition temperature of 138°C. The key advantages of the proposed...... SIPOF are low water absorption, high operating temperature and chemical inertness to acids and bases and many polar solvents as compared to the conventional poly-methyl-methacrylate (PMMA) and polystyrene based POFs. In addition, the fiber Bragg grating writing time is short compared to microstructured...

  2. Widely tunable asymmetric long-period fiber grating with high sensitivity using optical polymer on laser-ablated cladding.

    Science.gov (United States)

    Chen, Nan-Kuang; Hsu, Der-Yi; Chi, Sien

    2007-08-01

    We demonstrate high-efficiency, wideband-tunable, laser-ablated long-period fiber gratings that use an optical polymer overlay. Portions of the fiber cladding are periodically removed by CO(2) laser pulses to induce periodic index changes for coupling the core mode into cladding modes. An optical polymer with a high thermo-optic coefficient with a dispersion distinct from that of silica is used on a deep-ablated cladding structure so that the effective indices of cladding modes become dispersive and the resonant wavelengths can be efficiently tuned. The tuning efficiency can be as high as 15.8 nm/ degrees C, and the tuning range can be wider than 105 nm (1545-1650 nm).

  3. Highly stretchable carbon aerogels.

    Science.gov (United States)

    Guo, Fan; Jiang, Yanqiu; Xu, Zhen; Xiao, Youhua; Fang, Bo; Liu, Yingjun; Gao, Weiwei; Zhao, Pei; Wang, Hongtao; Gao, Chao

    2018-02-28

    Carbon aerogels demonstrate wide applications for their ultralow density, rich porosity, and multifunctionalities. Their compressive elasticity has been achieved by different carbons. However, reversibly high stretchability of neat carbon aerogels is still a great challenge owing to their extremely dilute brittle interconnections and poorly ductile cells. Here we report highly stretchable neat carbon aerogels with a retractable 200% elongation through hierarchical synergistic assembly. The hierarchical buckled structures and synergistic reinforcement between graphene and carbon nanotubes enable a temperature-invariable, recoverable stretching elasticity with small energy dissipation (~0.1, 100% strain) and high fatigue resistance more than 10 6 cycles. The ultralight carbon aerogels with both stretchability and compressibility were designed as strain sensors for logic identification of sophisticated shape conversions. Our methodology paves the way to highly stretchable carbon and neat inorganic materials with extensive applications in aerospace, smart robots, and wearable devices.

  4. Stretchable antenna for wearable electronics

    KAUST Repository

    Hussain, Muhammad Mustafa; Hussain, Aftab Mustansir; Shamim, Atif; Ghaffar, Farhan Abdul

    2017-01-01

    Various examples are provided for stretchable antennas that can be used for applications such as wearable electronics. In one example, a stretchable antenna includes a flexible support structure including a lateral spring section having a proximal

  5. Stretchable electronics for wearable and high-current applications

    Science.gov (United States)

    Hilbich, Daniel; Shannon, Lesley; Gray, Bonnie L.

    2016-04-01

    Advances in the development of novel materials and fabrication processes are resulting in an increased number of flexible and stretchable electronics applications. This evolving technology enables new devices that are not readily fabricated using traditional silicon processes, and has the potential to transform many industries, including personalized healthcare, consumer electronics, and communication. Fabrication of stretchable devices is typically achieved through the use of stretchable polymer-based conductors, or more rigid conductors, such as metals, with patterned geometries that can accommodate stretching. Although the application space for stretchable electronics is extensive, the practicality of these devices can be severely limited by power consumption and cost. Moreover, strict process flows can impede innovation that would otherwise enable new applications. In an effort to overcome these impediments, we present two modified approaches and applications based on a newly developed process for stretchable and flexible electronics fabrication. This includes the development of a metallization pattern stamping process allowing for 1) stretchable interconnects to be directly integrated with stretchable/wearable fabrics, and 2) a process variation enabling aligned multi-layer devices with integrated ferromagnetic nanocomposite polymer components enabling a fully-flexible electromagnetic microactuator for large-magnitude magnetic field generation. The wearable interconnects are measured, showing high conductivity, and can accommodate over 20% strain before experiencing conductive failure. The electromagnetic actuators have been fabricated and initial measurements show well-aligned, highly conductive, isolated metal layers. These two applications demonstrate the versatility of the newly developed process and suggest potential for its furthered use in stretchable electronics and MEMS applications.

  6. Time-dependent variation of fiber Bragg grating reflectivity in PMMA-based polymer optical fibers

    DEFF Research Database (Denmark)

    Saez-Rodriguez, D.; Nielsen, Kristian; Bang, Ole

    2015-01-01

    the material photosensitivity. After the inscription, the strain was released, and the FBGs spectra were monitored. We initially observed a decrease of the reflection down to zero after which it began to increase. After that, strain tests were carried out to confirm the results, and finally the gratings were...

  7. Polymer PCF Bragg grating sensors based on poly(methyl methacrylate) and TOPAS cyclic olefin copolymer

    DEFF Research Database (Denmark)

    Johnson, Ian P; Webb, David J; Kalli, Kyriacos

    2011-01-01

    mode PCF with a core diameter of 6μm based on TOPAS cyclic olefin copolymer. Bragg grating inscription was achieved using a 30mW continuous wave 325nm helium cadmium laser. Both TOPAS and PMMA fibre have a large attenuation of around 1dB/cm in the 1550nm spectral region, limiting fibre lengths...

  8. Microfluidic stretchable RF electronics.

    Science.gov (United States)

    Cheng, Shi; Wu, Zhigang

    2010-12-07

    Stretchable electronics is a revolutionary technology that will potentially create a world of radically different electronic devices and systems that open up an entirely new spectrum of possibilities. This article proposes a microfluidic based solution for stretchable radio frequency (RF) electronics, using hybrid integration of active circuits assembled on flex foils and liquid alloy passive structures embedded in elastic substrates, e.g. polydimethylsiloxane (PDMS). This concept was employed to implement a 900 MHz stretchable RF radiation sensor, consisting of a large area elastic antenna and a cluster of conventional rigid components for RF power detection. The integrated radiation sensor except the power supply was fully embedded in a thin elastomeric substrate. Good electrical performance of the standalone stretchable antenna as well as the RF power detection sub-module was verified by experiments. The sensor successfully detected the RF radiation over 5 m distance in the system demonstration. Experiments on two-dimensional (2D) stretching up to 15%, folding and twisting of the demonstrated sensor were also carried out. Despite the integrated device was severely deformed, no failure in RF radiation sensing was observed in the tests. This technique illuminates a promising route of realizing stretchable and foldable large area integrated RF electronics that are of great interest to a variety of applications like wearable computing, health monitoring, medical diagnostics, and curvilinear electronics.

  9. High-Tg TOPAS microstructured polymer optical fiber for fiber Bragg grating strain sensing at 110 degrees

    DEFF Research Database (Denmark)

    Markos, Christos; Stefani, Alessio; Nielsen, Kristian

    2013-01-01

    We present the fabrication and characterization of fiber Bragg gratings (FBGs) in an endlessly single-mode microstructured polymer optical fiber (mPOF) made of humidity-insensitive high-Tg TOPAS cyclic olefin copolymer. The mPOF is the first made from grade 5013 TOPAS with a glass transition...... temperature of Tg = 135°C and we experimentally demonstrate high strain operation (2.5%) of the FBG at 98°C and stable operation up to a record high temperature of 110°C. The Bragg wavelengths of the FBGs are around 860 nm, where the propagation loss is 5.1dB/m, close to the fiber loss minimum of 3.67d...

  10. Surface morphology of refractive-index waveguide gratings fabricated in polymer films

    Science.gov (United States)

    Dong, Yi; Song, Yan-fang; Ma, Lei; Gao, Fang-fang

    2016-09-01

    The characteristic modifications are reported on the surface of polymeric waveguide film in the process of volume- grating fabrication. The light from a mode-locked 76 MHz femtosecond laser with pulse duration of 200 fs and wavelength of 800 nm is focused normal to the surface of the sample. The surface morphology modifications are ascribed to a fact that surface swelling occurs during the process. Periodic micro-structure is inscribed with increasing incident power. The laser-induced swelling threshold on the grating, which is higher than that of two-photon initiated photo-polymerization (TPIP) (8 mW), is verified to be about 20 mW. It is feasible to enhance the surface smoothness of integrated optics devices for further encapsulation. The variation of modulation depth is studied for different values of incident power and scan spacing. Ablation accompanied with surface swelling appears when the power is higher. By optimizing the laser carving parameters, highly efficient grating devices can be fabricated.

  11. Skin electronics from scalable fabrication of an intrinsically stretchable transistor array.

    Science.gov (United States)

    Wang, Sihong; Xu, Jie; Wang, Weichen; Wang, Ging-Ji Nathan; Rastak, Reza; Molina-Lopez, Francisco; Chung, Jong Won; Niu, Simiao; Feig, Vivian R; Lopez, Jeffery; Lei, Ting; Kwon, Soon-Ki; Kim, Yeongin; Foudeh, Amir M; Ehrlich, Anatol; Gasperini, Andrea; Yun, Youngjun; Murmann, Boris; Tok, Jeffery B-H; Bao, Zhenan

    2018-03-01

    Skin-like electronics that can adhere seamlessly to human skin or within the body are highly desirable for applications such as health monitoring, medical treatment, medical implants and biological studies, and for technologies that include human-machine interfaces, soft robotics and augmented reality. Rendering such electronics soft and stretchable-like human skin-would make them more comfortable to wear, and, through increased contact area, would greatly enhance the fidelity of signals acquired from the skin. Structural engineering of rigid inorganic and organic devices has enabled circuit-level stretchability, but this requires sophisticated fabrication techniques and usually suffers from reduced densities of devices within an array. We reasoned that the desired parameters, such as higher mechanical deformability and robustness, improved skin compatibility and higher device density, could be provided by using intrinsically stretchable polymer materials instead. However, the production of intrinsically stretchable materials and devices is still largely in its infancy: such materials have been reported, but functional, intrinsically stretchable electronics have yet to be demonstrated owing to the lack of a scalable fabrication technology. Here we describe a fabrication process that enables high yield and uniformity from a variety of intrinsically stretchable electronic polymers. We demonstrate an intrinsically stretchable polymer transistor array with an unprecedented device density of 347 transistors per square centimetre. The transistors have an average charge-carrier mobility comparable to that of amorphous silicon, varying only slightly (within one order of magnitude) when subjected to 100 per cent strain for 1,000 cycles, without current-voltage hysteresis. Our transistor arrays thus constitute intrinsically stretchable skin electronics, and include an active matrix for sensory arrays, as well as analogue and digital circuit elements. Our process offers a

  12. Hydrophobic polymer covered by a grating electrode for converting the mechanical energy of water droplets into electrical energy

    Science.gov (United States)

    Helseth, L. E.; Guo, X. D.

    2016-04-01

    Water contact electric harvesting has a great potential as a new energy technology for powering small-scale electronics, but a better understanding of the dynamics governing the conversion from mechanical to electrical energy on the polymer surfaces is needed. Important questions are how current correlates with droplet kinetic energy and what happens to the charge dynamics when a large number of droplets are incident on the polymer simultaneously. Here we address these questions by studying the current that is generated in an external electrical circuit when water droplets impinge on hydrophobic fluorinated ethylene propylene film containing a grating electrode on the back side. Droplets moving down an inclined polymer plane exhibit a characteristic periodic current time trace, and it is found that the peak current scales with sine of the inclination angle. For single droplets in free fall impinging onto the polymer, it is found that the initial peak current scales with the height of the free fall. The transition from individual droplets to a nearly continuous stream was investigated using the spectral density of the current signal. In both regimes, the high frequency content of the spectral density scales as f -2. For low frequencies, the low frequency content at low volume rates was noisy but nearly constant, whereas for high volume rates an increase with frequency is observed. It is demonstrated that the output signal from the system exposed to water droplets from a garden hose can be rectified and harvested by a 33 μF capacitor, where the stored energy increases at a rate of about 20 μJ in 100 s.

  13. Investigating the Strain, Temperature and Humidity Sensitivity of a Multimode Graded-Index Perfluorinated Polymer Optical Fiber with Bragg Grating.

    Science.gov (United States)

    Zheng, Yulong; Bremer, Kort; Roth, Bernhard

    2018-05-05

    In this work we investigate the strain, temperature and humidity sensitivity of a Fiber Bragg Grating (FBG) inscribed in a near infrared low-loss multimode perfluorinated polymer optical fiber based on cyclic transparent optical polymer (CYTOP). For this purpose, FBGs were inscribed into the multimode CYTOP fiber with a core diameter of 50 µm by using a krypton fluoride (KrF) excimer laser and the phase mask method. The evolution of the reflection spectrum of the FBG detected with a multimode interrogation technique revealed a single reflection peak with a full width at half maximum (FHWM) bandwidth of about 9 nm. Furthermore, the spectral envelope of the single FBG reflection peak can be optimized depending on the KrF excimer laser irradiation time. A linear shift of the Bragg wavelength due to applied strain, temperature and humidity was measured. Furthermore, depending on irradiation time of the KrF excimer laser, both the failure strain and strain sensitivity of the multimode fiber with FBG can be controlled. The inherent low light attenuation in the near infrared wavelength range (telecommunication window) of the multimode CYTOP fiber and the single FBG reflection peak when applying the multimode interrogation set-up will allow for new applications in the area of telecommunication and optical sensing.

  14. Intrinsically stretchable supercapacitors composed of polypyrrole electrodes and highly stretchable gel electrolyte.

    Science.gov (United States)

    Zhao, Chen; Wang, Caiyun; Yue, Zhilian; Shu, Kewei; Wallace, Gordon G

    2013-09-25

    There has been an emerging interest in stretchable power sources compatible with flexible/wearable electronics. Such power sources must be able to withstand large mechanical strains and still maintain function. Here we report a highly stretchable H3PO4-poly(vinyl alcohol) (PVA) polymer electrolyte obtained by optimizing the polymer molecular weight and its weight ratio to H3PO4 in terms of conductivity and mechanical properties. The electrolyte demonstrates a high conductivity of 3.4 × 10(-3) S cm(-1), and a high fracture strain at 410% elongation. It is mechanically robust with a tensile strength of 2 MPa and a Young's modulus of 1 MPa, and displays a small plastic deformation (5%) after 1000 stretching cycles at 100% strain. A stretchable supercapacitor device has been developed based on buckled polypyrrole electrodes and the polymer electrolyte. The device shows only a small capacitance loss of 5.6% at 30% strain, and can retain 81% of the initial capacitance after 1000 cycles of such stretching.

  15. Fast Bragg Grating Inscription in PMMA Polymer Optical Fibres: Impact of Thermal Pre-Treatment of Preforms

    Directory of Open Access Journals (Sweden)

    Carlos A. F. Marques

    2017-04-01

    Full Text Available In this work, fibre Bragg gratings (FBGs were inscribed in two different undoped poly- (methyl methacrylate (PMMA polymer optical fibres (POFs using different types of UV lasers and their inscription times, temperature and strain sensitivities are investigated. The POF Bragg gratings (POFBGs were inscribed using two UV lasers: a continuous UV HeCd @325 nm laser and a pulsed UV KrF @248 nm laser. Two PMMA POFs are used in which the primary and secondary preforms (during the two-step drawing process have a different thermal treatment. The PMMA POFs drawn in which the primary or secondary preform is not specifically pre-treated need longer inscription time than the fibres drawn where both preforms have been pre-annealed at 80 °C for 2 weeks. Using both UV lasers, for the latter fibre much less inscription time is needed compared to another homemade POF. The properties of a POF fabricated with both preforms thermally well annealed are different from those in which just one preform step process is thermally treated, with the first POFs being much less sensitive to thermal treatment. The influence of annealing on the strain and temperature sensitivities of the fibres prior to FBG inscription is also discussed, where it is observed that the fibre produced from a two-step drawing process with well-defined pre-annealing of both preforms did not produce any significant difference in sensitivity. The results indicate the impact of preform thermal pre-treatment before the PMMA POFs drawing, which can be an essential characteristic in the view of developing POF sensors technology.

  16. Skin electronics from scalable fabrication of an intrinsically stretchable transistor array

    Science.gov (United States)

    Wang, Sihong; Xu, Jie; Wang, Weichen; Wang, Ging-Ji Nathan; Rastak, Reza; Molina-Lopez, Francisco; Chung, Jong Won; Niu, Simiao; Feig, Vivian R.; Lopez, Jeffery; Lei, Ting; Kwon, Soon-Ki; Kim, Yeongin; Foudeh, Amir M.; Ehrlich, Anatol; Gasperini, Andrea; Yun, Youngjun; Murmann, Boris; Tok, Jeffery B.-H.; Bao, Zhenan

    2018-03-01

    Skin-like electronics that can adhere seamlessly to human skin or within the body are highly desirable for applications such as health monitoring, medical treatment, medical implants and biological studies, and for technologies that include human-machine interfaces, soft robotics and augmented reality. Rendering such electronics soft and stretchable—like human skin—would make them more comfortable to wear, and, through increased contact area, would greatly enhance the fidelity of signals acquired from the skin. Structural engineering of rigid inorganic and organic devices has enabled circuit-level stretchability, but this requires sophisticated fabrication techniques and usually suffers from reduced densities of devices within an array. We reasoned that the desired parameters, such as higher mechanical deformability and robustness, improved skin compatibility and higher device density, could be provided by using intrinsically stretchable polymer materials instead. However, the production of intrinsically stretchable materials and devices is still largely in its infancy: such materials have been reported, but functional, intrinsically stretchable electronics have yet to be demonstrated owing to the lack of a scalable fabrication technology. Here we describe a fabrication process that enables high yield and uniformity from a variety of intrinsically stretchable electronic polymers. We demonstrate an intrinsically stretchable polymer transistor array with an unprecedented device density of 347 transistors per square centimetre. The transistors have an average charge-carrier mobility comparable to that of amorphous silicon, varying only slightly (within one order of magnitude) when subjected to 100 per cent strain for 1,000 cycles, without current-voltage hysteresis. Our transistor arrays thus constitute intrinsically stretchable skin electronics, and include an active matrix for sensory arrays, as well as analogue and digital circuit elements. Our process offers a

  17. Improving information density in ferroelectric polymer films by using nanoimprinted gratings

    Science.gov (United States)

    Martínez-Tong, Daniel E.; Soccio, Michela; Rueda, Daniel R.; Nogales, Aurora; García-Gutiérrez, Mari Cruz; Ezquerra, Tiberio A.

    2015-03-01

    The development of polymer non-volatile memories depends on the effective fabrication of devices with high density of information. Well-defined low aspect ratio nanogratings on thin films of poly(vinylidene fluoride-trifluoroethylene) copolymers can be fabricated by using Nanoimprint Lithography (NIL). By using these nanogratings, an improved management of writing and reading information can be reached as revealed by Piezoresponse Force Microscopy (PFM). Structural investigation by means of Grazing Incidence X-ray (GIX) scattering techniques indicates that the physical confinement generated by nanoimprint promotes the development of smaller and edge-on oriented crystals. Our results evidence that one-dimensional nanostructuring can be a straightforward approach to improve the control of the polarization in ferroelectric polymer thin films.

  18. Ultra-stretchable Interconnects for high-density stretchable electronics

    NARCIS (Netherlands)

    Shafqat, S.; Hoefnagels, J.P.M.; Savov, A.; Joshi, S.; Dekker, R.; Geers, M.G.D.

    2017-01-01

    The exciting field of stretchable electronics (SE) promises numerous novel applications, particularly in-body and medical diagnostics devices. However, future advanced SE miniature devices will require high-density, extremely stretchable interconnects with micron-scale footprints, which calls for

  19. Screen-Printing Fabrication and Characterization of Stretchable Electronics.

    Science.gov (United States)

    Suikkola, Jari; Björninen, Toni; Mosallaei, Mahmoud; Kankkunen, Timo; Iso-Ketola, Pekka; Ukkonen, Leena; Vanhala, Jukka; Mäntysalo, Matti

    2016-05-13

    This article focuses on the fabrication and characterization of stretchable interconnects for wearable electronics applications. Interconnects were screen-printed with a stretchable silver-polymer composite ink on 50-μm thick thermoplastic polyurethane. The initial sheet resistances of the manufactured interconnects were an average of 36.2 mΩ/◽, and half the manufactured samples withstood single strains of up to 74%. The strain proportionality of resistance is discussed, and a regression model is introduced. Cycling strain increased resistance. However, the resistances here were almost fully reversible, and this recovery was time-dependent. Normalized resistances to 10%, 15%, and 20% cyclic strains stabilized at 1.3, 1.4, and 1.7. We also tested the validity of our model for radio-frequency applications through characterization of a stretchable radio-frequency identification tag.

  20. Screen-Printing Fabrication and Characterization of Stretchable Electronics

    Science.gov (United States)

    Suikkola, Jari; Björninen, Toni; Mosallaei, Mahmoud; Kankkunen, Timo; Iso-Ketola, Pekka; Ukkonen, Leena; Vanhala, Jukka; Mäntysalo, Matti

    2016-01-01

    This article focuses on the fabrication and characterization of stretchable interconnects for wearable electronics applications. Interconnects were screen-printed with a stretchable silver-polymer composite ink on 50-μm thick thermoplastic polyurethane. The initial sheet resistances of the manufactured interconnects were an average of 36.2 mΩ/◽, and half the manufactured samples withstood single strains of up to 74%. The strain proportionality of resistance is discussed, and a regression model is introduced. Cycling strain increased resistance. However, the resistances here were almost fully reversible, and this recovery was time-dependent. Normalized resistances to 10%, 15%, and 20% cyclic strains stabilized at 1.3, 1.4, and 1.7. We also tested the validity of our model for radio-frequency applications through characterization of a stretchable radio-frequency identification tag. PMID:27173424

  1. Production and Characterization of Polycarbonate Microstructured Polymer Optical Fiber Bragg Grating Sensor

    DEFF Research Database (Denmark)

    Fasano, Andrea; Woyessa, Getinet; Stajanca, P.

    2015-01-01

    , such as casting of pol-ymer granulates into a solid rod, machining and drilling of a 3-ring hexagonal lattice of holes into it, and finally drawing into fiber. We demonstrate that the obtained PC mPOF is photosensitive and FBGs can be conveniently inscribed into it, thereby enabling FBG-based temperature...... and strain sensing. The PC optical fibers are for some applications an attractive alternative to conventional materials used in POF fabrication, such as polymethyl methacrylate (PMMA). In general, PC can be used at temperature up to 120 °C and breaks at considerably higher strains than PMMA....

  2. Drop casting of stiffness gradients for chip integration into stretchable substrates

    International Nuclear Information System (INIS)

    Naserifar, Naser; LeDuc, Philip R; Fedder, Gary K

    2017-01-01

    Stretchable electronics have demonstrated promise within unobtrusive wearable systems in areas such as health monitoring and medical therapy. One significant question is whether it is more advantageous to develop holistic stretchable electronics or to integrate mature CMOS into stretchable electronic substrates where the CMOS process is separated from the mechanical processing steps. A major limitation with integrating CMOS is the dissimilar interface between the soft stretchable and hard CMOS materials. To address this, we developed an approach to pattern an elastomeric polymer layer with spatially varying mechanical properties around CMOS electronics to create a controllable material stiffness gradient. Our experimental approach reveals that modifying the interfaces can increase the strain failure threshold up to 30% and subsequently decreases delamination. The stiffness gradient in the polymer layer provides a safe region for electronic chips to function under a substrate tensile strain up to 150%. These results will have impacts in diverse applications including skin sensors and wearable health monitoring systems. (paper)

  3. Highly stretchable resistive pressure sensors using a conductive elastomeric composite on a micropyramid array.

    Science.gov (United States)

    Choong, Chwee-Lin; Shim, Mun-Bo; Lee, Byoung-Sun; Jeon, Sanghun; Ko, Dong-Su; Kang, Tae-Hyung; Bae, Jihyun; Lee, Sung Hoon; Byun, Kyung-Eun; Im, Jungkyun; Jeong, Yong Jin; Park, Chan Eon; Park, Jong-Jin; Chung, U-In

    2014-06-04

    A stretchable resistive pressure sensor is achieved by coating a compressible substrate with a highly stretchable electrode. The substrate contains an array of microscale pyramidal features, and the electrode comprises a polymer composite. When the pressure-induced geometrical change experienced by the electrode is maximized at 40% elongation, a sensitivity of 10.3 kPa(-1) is achieved. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Fiber design and realization of point-by-point written fiber Bragg gratings in polymer optical fibers

    DEFF Research Database (Denmark)

    Stefani, Alessio; Stecher, Matthias; Town, Graham E.

    2012-01-01

    the gratings make the point-by-point grating writing technique very interesting and would appear to be able to fill this technological gap. On the other end this technique is hardly applicable for microstructured fibers because of the writing beam being scattered by the air-holes. We report on the design...... and because they allow to tune the guiding parameters by modifying the microstructure. Now a days the only technique used to write gratings in such fibers is the phase mask technique with UV light illumination. Despite the good results that have been obtained, a limited flexibility on the grating design...... and the very long times required for the writing of FBGs raise some questions about the possibility of exporting POF FBGs and the sensors based on them from the laboratory bench to the mass production market. The possibility of arbitrary design of fiber Bragg gratings and the very short time required to write...

  5. Ultra-Stretchable Interconnects for High-Density Stretchable Electronics

    Directory of Open Access Journals (Sweden)

    Salman Shafqat

    2017-09-01

    Full Text Available The exciting field of stretchable electronics (SE promises numerous novel applications, particularly in-body and medical diagnostics devices. However, future advanced SE miniature devices will require high-density, extremely stretchable interconnects with micron-scale footprints, which calls for proven standardized (complementary metal-oxide semiconductor (CMOS-type process recipes using bulk integrated circuit (IC microfabrication tools and fine-pitch photolithography patterning. Here, we address this combined challenge of microfabrication with extreme stretchability for high-density SE devices by introducing CMOS-enabled, free-standing, miniaturized interconnect structures that fully exploit their 3D kinematic freedom through an interplay of buckling, torsion, and bending to maximize stretchability. Integration with standard CMOS-type batch processing is assured by utilizing the Flex-to-Rigid (F2R post-processing technology to make the back-end-of-line interconnect structures free-standing, thus enabling the routine microfabrication of highly-stretchable interconnects. The performance and reproducibility of these free-standing structures is promising: an elastic stretch beyond 2000% and ultimate (plastic stretch beyond 3000%, with <0.3% resistance change, and >10 million cycles at 1000% stretch with <1% resistance change. This generic technology provides a new route to exciting highly-stretchable miniature devices.

  6. Design and characterization of ultra-stretchable monolithic silicon fabric

    KAUST Repository

    Rojas, Jhonathan Prieto

    2014-10-13

    Stretchable electronic systems can play instrumental role for reconfigurable macro-electronics such as distributed sensor networks for wearable and bio-integrated electronics. Typically, polymer composite based materials and its deterministic design as interconnects are used to achieve such systems. Nonetheless, non-polymeric inorganic silicon is the predominant material for 90% of electronics. Therefore, we report the design and fabrication of an all silicon based network of hexagonal islands connected through spiral springs to form an ultra-stretchable arrangement for complete compliance to highly asymmetric shapes. Several design parameters are considered and their validation is carried out through finite element analysis. The fabrication process is based on conventional microfabrication techniques and the measured stretchability is more than 1000% for single spirals and area expansions as high as 30 folds in arrays. The reported method can provide ultra-stretchable and adaptable electronic systems for distributed network of high-performance macro-electronics especially useful for wearable electronics and bio-integrated devices.

  7. Design and characterization of ultra-stretchable monolithic silicon fabric

    KAUST Repository

    Rojas, Jhonathan Prieto; Carreno, Armando Arpys Arevalo; Foulds, I. G.; Hussain, Muhammad Mustafa

    2014-01-01

    Stretchable electronic systems can play instrumental role for reconfigurable macro-electronics such as distributed sensor networks for wearable and bio-integrated electronics. Typically, polymer composite based materials and its deterministic design as interconnects are used to achieve such systems. Nonetheless, non-polymeric inorganic silicon is the predominant material for 90% of electronics. Therefore, we report the design and fabrication of an all silicon based network of hexagonal islands connected through spiral springs to form an ultra-stretchable arrangement for complete compliance to highly asymmetric shapes. Several design parameters are considered and their validation is carried out through finite element analysis. The fabrication process is based on conventional microfabrication techniques and the measured stretchability is more than 1000% for single spirals and area expansions as high as 30 folds in arrays. The reported method can provide ultra-stretchable and adaptable electronic systems for distributed network of high-performance macro-electronics especially useful for wearable electronics and bio-integrated devices.

  8. A stretchable and screen-printable conductive ink for stretchable electronics

    Science.gov (United States)

    Mohammed, Anwar; Pecht, Michael

    2016-10-01

    Stretchable electronics can offer an added degree of design freedom and generate products with unprecedented capabilities. Stretchable conductive ink serving as interconnect, is a key enabler for stretchable electronics. This paper focuses on the development of a stretchable and screen printable conductive ink which could be stretched more than 500 cycles at 20% strain while maintaining electrical and mechanical integrity. The screen printable and stretchable conductive ink developed in this paper marks an important milestone for this nascent technology.

  9. Bragg grating photo-inscription in doped microstructured polymer optical fiber by 400 nm femtosecond laser pulses

    DEFF Research Database (Denmark)

    Hu, X.; Woyessa, Getinet; Kinet, D.

    2016-01-01

    In this paper, we report the manufacturing of high-quality endlessly single-mode doped microstructured poly(methyl methacrylate) (PMMA) optical fibers. Bragg gratings are photo-inscribed in such fibers by means of 400 nm femtosecond laser pulses through a 1060-nm-period uniform phase mask...

  10. Stretchable and Tunable Microtectonic ZnO-Based Sensors and Photonics.

    Science.gov (United States)

    Gutruf, Philipp; Zeller, Eike; Walia, Sumeet; Nili, Hussein; Sriram, Sharath; Bhaskaran, Madhu

    2015-09-16

    The concept of realizing electronic applications on elastically stretchable "skins" that conform to irregularly shaped surfaces is revolutionizing fundamental research into mechanics and materials that can enable high performance stretchable devices. The ability to operate electronic devices under various mechanically stressed states can provide a set of unique functionalities that are beyond the capabilities of conventional rigid electronics. Here, a distinctive microtectonic effect enabled oxygen-deficient, nanopatterned zinc oxide (ZnO) thin films on an elastomeric substrate are introduced to realize large area, stretchable, transparent, and ultraportable sensors. The unique surface structures are exploited to create stretchable gas and ultraviolet light sensors, where the functional oxide itself is stretchable, both of which outperform their rigid counterparts under room temperature conditions. Nanoscale ZnO features are embedded in an elastomeric matrix function as tunable diffraction gratings, capable of sensing displacements with nanometre accuracy. These devices and the microtectonic oxide thin film approach show promise in enabling functional, transparent, and wearable electronics. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Stretchable All-Gel-State Fiber-Shaped Supercapacitors Enabled by Macromolecularly Interconnected 3D Graphene/Nanostructured Conductive Polymer Hydrogels.

    Science.gov (United States)

    Li, Panpan; Jin, Zhaoyu; Peng, Lele; Zhao, Fei; Xiao, Dan; Jin, Yong; Yu, Guihua

    2018-05-01

    Nanostructured conductive polymer hydrogels (CPHs) have been extensively applied in energy storage owing to their advantageous features, such as excellent electrochemical activity and relatively high electrical conductivity, yet the fabrication of self-standing and flexible electrode-based CPHs is still hampered by their limited mechanical properties. Herein, macromolecularly interconnected 3D graphene/nanostructured CPH is synthesized via self-assembly of CPHs and graphene oxide macrostructures. The 3D hybrid hydrogel shows uniform interconnectivity and enhanced mechanical properties due to the strong macromolecular interaction between the CPHs and graphene, thus greatly reducing aggregation in the fiber-shaping process. A proof-of-concept all-gel-state fibrous supercapacitor based on the 3D polyaniline/graphene hydrogel is fabricated to demonstrate the outstanding flexibility and mouldability, as well as superior electrochemical properties enabled by this 3D hybrid hydrogel design. The proposed device can achieve a large strain (up to ≈40%), and deliver a remarkable volumetric energy density of 8.80 mWh cm -3 (at power density of 30.77 mW cm -3 ), outperforming many fiber-shaped supercapacitors reported previously. The all-hydrogel design opens up opportunities in the fabrication of next-generation wearable and portable electronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Systematic approach for the calibration of humidity sensitive polyimide recoated fibre Bragg gratings for measuring humidity and temperature and their application for measuring moisture absorption in polymers

    International Nuclear Information System (INIS)

    Young, T J; Lodeiro, M J; Gower, M R L; Sassi, M B

    2013-01-01

    This paper describes a systematic method for calibrating polyimide recoated fibre Bragg grating (FBG) optical fibres and the associated models used to measure temperature and relative humidity (RH) from 20 to 70 °C and 20% RH to 80% RH. The method was validated by comparing known values of temperature and RH with calculated values from two FBG sensors with different thicknesses of polyimide recoat. Results show good agreement, with a standard deviation error of 0.5 °C and 4.8% RH for temperature and humidity respectively. Drift in the measured wavelength was observed for both thicknesses of polyimide coating under the combined effect of elevated temperature and high humidity. This drift was reversed after a reduction in the humidity. Additional results are provided on the use of embedded polyimide recoated FBG optical fibres for measuring moisture ingress within polymers and composites. (paper)

  13. Bragg grating photo-inscription in doped microstructured polymer optical fiber by 400 nm femtosecond laser pulses.

    OpenAIRE

    Hu, X.; Woyessa, Getinet; Kinet, D.; Janting, Jakob; Nielsen, Kristian; Bang, Ole; Mégret, P.; Caucheteur, C.

    2016-01-01

    In this paper, we report the manufacturing of high-quality endlessly single-mode doped microstructured poly(methyl methacrylate) (PMMA) optical fibers. Bragg gratings are photo-inscribed in such fibers by means of 400 nm femtosecond laser pulses through a 1060-nm-period uniform phase mask. Preliminary results show a rapid growing process of the reflection band. To preserve a good spectral shape, the photo-inscription process was limited to ~20 seconds, yielding an FBG reflectivity close to 40 %.

  14. Improved power transfer to wearable systems through stretchable magnetic composites

    Science.gov (United States)

    Lazarus, N.; Bedair, S. S.

    2016-05-01

    The use of wireless power transfer is common in stretchable electronics since physical wiring can be easily destroyed as the system is stretched. This work presents the first demonstration of improved inductive power coupling to a stretchable system through the addition of a thin layer of ferroelastomeric material. A ferroelastomer, an elastomeric polymer loaded with magnetic particulates, has a permeability greater than one while retaining the ability to survive significant mechanical strains. A recently developed ferroelastomer composite based on sendust platelets within a soft silicone elastomer was incorporated into liquid metal stretchable inductors based on the liquid metal galinstan in fluidic channels. For a single-turn inductor, the maximum power transfer efficiency rises from 71 % with no backplane, to 81 % for a rigid ferrite backplane on the transmitter side alone, to 86 % with a ferroelastomer backplane on the receiver side as well. The coupling between a commercial wireless power transmitter coil with ferrite backplane to a five-turn liquid metal inductor was also investigated, finding an improvement in power transfer efficiency from 81 % with only a rigid backplane to 90 % with the addition of the ferroelastomer backplane. Both the single and multi-turn inductors were demonstrated surviving up to 50 % uniaxial applied strain.

  15. Smart, stretchable supercapacitors.

    Science.gov (United States)

    Chen, Xuli; Lin, Huijuan; Chen, Peining; Guan, Guozhen; Deng, Jue; Peng, Huisheng

    2014-07-09

    Smart supercapacitors are developed by depositing conducting polymers onto aligned carbon-nanotube sheets. These supercapacitors rapidly and reversibly demonstrate color changes in response to a variation in the level of stored energy and the chromatic transitions can be directly observed by the naked eye. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Stretchable Helical Architecture Inorganic-Organic Hetero Thermoelectric Generator

    KAUST Repository

    Rojas, Jhonathan Prieto; Singh, Devendra; Conchouso Gonzalez, David; Carreno, Armando Arpys Arevalo; Foulds, Ian G.; Hussain, Muhammad Mustafa

    2016-01-01

    To achieve higher power output from a thermoelectric generator (TEG), one needs to maintain a larger temperature difference between hot and cold end. In that regard, a stretchable TEG can be interesting to adaptively control the temperature difference. Here we show, the development of simple yet versatile and highly stretchable thermoelectric generators (TEGs), by combining well-known inorganic thermoelectric materials Bismuth Telluride and Antimony Telluride (Bi2Te3 and Sb2Te3) with organic substrates (Off-Stoichiometry Thiol-Enes polymer platform – OSTE, polyimide or paper) and novel helical architecture (double-arm spirals) to achieve over 100% stretchability. First, an OSTE-based TEG design demonstrates higher open circuit voltage generation at 100% strain than at rest, although it exhibits high internal resistance and a relatively complex fabrication process. The second, simpler TEG design, achieves a significant resistance reduction and two different structural substrates (PI and paper) are compared. The paper-based TEG generates 17 nW (ΔT = 75 °C) at 60% strain, which represents more than twice the power generation while at rest (zero strain). On the other hand, polyimide produces more conductive TE films and higher power (~35 nW at ΔT = 75 °C) but due to its higher thermal conductivity, power does not increase at stretch. In conclusion, highly stretchable TEGs can lead to higher temperature gradients (thus higher power generation), given that thermal conductivity of the structural material is low enough. Furthermore, either horizontal or vertical displacement can be achieved with double-arm helical architecture, hence allowing to extend the device to any nearby and mobile heat sink for continuous, effectively higher power generation.

  17. Stretchable Helical Architecture Inorganic-Organic Hetero Thermoelectric Generator

    KAUST Repository

    Rojas, Jhonathan Prieto

    2016-10-26

    To achieve higher power output from a thermoelectric generator (TEG), one needs to maintain a larger temperature difference between hot and cold end. In that regard, a stretchable TEG can be interesting to adaptively control the temperature difference. Here we show, the development of simple yet versatile and highly stretchable thermoelectric generators (TEGs), by combining well-known inorganic thermoelectric materials Bismuth Telluride and Antimony Telluride (Bi2Te3 and Sb2Te3) with organic substrates (Off-Stoichiometry Thiol-Enes polymer platform – OSTE, polyimide or paper) and novel helical architecture (double-arm spirals) to achieve over 100% stretchability. First, an OSTE-based TEG design demonstrates higher open circuit voltage generation at 100% strain than at rest, although it exhibits high internal resistance and a relatively complex fabrication process. The second, simpler TEG design, achieves a significant resistance reduction and two different structural substrates (PI and paper) are compared. The paper-based TEG generates 17 nW (ΔT = 75 °C) at 60% strain, which represents more than twice the power generation while at rest (zero strain). On the other hand, polyimide produces more conductive TE films and higher power (~35 nW at ΔT = 75 °C) but due to its higher thermal conductivity, power does not increase at stretch. In conclusion, highly stretchable TEGs can lead to higher temperature gradients (thus higher power generation), given that thermal conductivity of the structural material is low enough. Furthermore, either horizontal or vertical displacement can be achieved with double-arm helical architecture, hence allowing to extend the device to any nearby and mobile heat sink for continuous, effectively higher power generation.

  18. Enhanced tolerance to stretch-induced performance degradation of stretchable MnO2-based supercapacitors.

    Science.gov (United States)

    Huang, Yan; Huang, Yang; Meng, Wenjun; Zhu, Minshen; Xue, Hongtao; Lee, Chun-Sing; Zhi, Chunyi

    2015-02-04

    The performance of many stretchable electronics, such as energy storage devices and strain sensors, is highly limited by the structural breakdown arising from the stretch imposed. In this article, we focus on a detailed study on materials matching between functional materials and their conductive substrate, as well as enhancement of the tolerance to stretch-induced performance degradation of stretchable supercapacitors, which are essential for the design of a stretchable device. It is revealed that, being widely utilized as the electrode material of the stretchable supercapacitor, metal oxides such as MnO2 nanosheets have serious strain-induced performance degradation due to their rigid structure. In comparison, with conducting polymers like a polypyrrole (PPy) film as the electrochemically active material, the performance of stretchable supercapacitors can be well preserved under strain. Therefore, a smart design is to combine PPy with MnO2 nanosheets to achieve enhanced tolerance to strain-induced performance degradation of MnO2-based supercapacitors, which is realized by fabricating an electrode of PPy-penetrated MnO2 nanosheets. The composite electrodes exhibit a remarkable enhanced tolerance to strain-induced performance degradation with well-preserved performance over 93% under strain. The detailed morphology and electrochemical impedance variations are investigated for the mechanism analyses. Our work presents a systematic investigation on the selection and matching of electrode materials for stretchable supercapacitors to achieve high performance and great tolerance to strain, which may guide the selection of functional materials and their substrate materials for the next-generation of stretchable electronics.

  19. Stretchable Fluorescent Polyfluorene/Acrylonitrile Butadiene Rubber Blend Electrospun Fibers through Physical Interaction and Geometrical Confinement.

    Science.gov (United States)

    Hsieh, Hui-Ching; Chen, Jung-Yao; Lee, Wen-Ya; Bera, Debaditya; Chen, Wen-Chang

    2018-03-01

    Stretchable light-emitting polymers are important for wearable electronics; however, the development of intrinsic stretchable light-emitting materials with great performance under large applied strain is the most critical challenge. Herein, this study demonstrates the fabrication of stretchable fluorescent poly[(9,9-bis(3'-(N,N-dimethylamino)propyl)-2,7-fluorene)-alt-2,7-(9,9-dioctyl-fluorene)]/acrylonitrile butadiene rubber (PFN/NBR) blend nanofibers using the uniaxial electrospinning technique. The physical interaction of PFN with NBR and the geometrical confinement of nanofibers are employed to reduce PFN aggregation, leading to the high photoluminescence quantum yield of 35.7%. Such fiber mat film shows stable blue emission at the 50% strain for 200 stretching/release cycles, which has potential applications in smart textiles. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  20. Progress and Prospects in Stretchable Electroluminescent Devices

    Directory of Open Access Journals (Sweden)

    Wang Jiangxin

    2017-03-01

    Full Text Available Stretchable electroluminescent (EL devices are a new form of mechanically deformable electronics that are gaining increasing interests and believed to be one of the essential technologies for next generation lighting and display applications. Apart from the simple bending capability in flexible EL devices, the stretchable EL devices are required to withstand larger mechanical deformations and accommodate stretching strain beyond 10%. The excellent mechanical conformability in these devices enables their applications in rigorous mechanical conditions such as flexing, twisting, stretching, and folding.The stretchable EL devices can be conformably wrapped onto arbitrary curvilinear surface and respond seamlessly to the external or internal forces, leading to unprecedented applications that cannot be addressed with conventional technologies. For example, they are in demand for wide applications in biomedical-related devices or sensors and soft interactive display systems, including activating devices for photosensitive drug, imaging apparatus for internal tissues, electronic skins, interactive input and output devices, robotics, and volumetric displays. With increasingly stringent demand on the mechanical requirements, the fabrication of stretchable EL device is encountering many challenges that are difficult to resolve. In this review, recent progresses in the stretchable EL devices are covered with a focus on the approaches that are adopted to tackle materials and process challenges in stretchable EL devices and delineate the strategies in stretchable electronics. We first introduce the emission mechanisms that have been successfully demonstrated on stretchable EL devices. Limitations and advantages of the different mechanisms for stretchable EL devices are also discussed. Representative reports are reviewed based on different structural and material strategies. Unprecedented applications that have been enabled by the stretchable EL devices are

  1. Stretchable polyurethane sponge reinforced magnetorheological material with enhanced mechanical properties

    International Nuclear Information System (INIS)

    Ge, Lin; Xuan, Shouhu; Liao, Guojiang; Yin, Tiantian; Gong, Xinglong

    2015-01-01

    A stretchable magnetorheological material (SMRM) consisting of micro-meter carbonyl iron (CI) particles, low cross-linking polyurethane (PU) polymer and porous PU sponge has been developed. Due to the presence of the PU sponge, the high-performance MR material can be reversibly stretched or bent, just as MR elastomers. When the CI content increases to 80 wt%, the magnetic induced modulus of the MR material can reach as high as 7.34 MPa and the corresponding relative MR effect increases to 820%. A possible strengthening mechanism of the SMRM was proposed. The attractive mechanical properties make the SMRM a promising candidate for future high-performance devices. (technical note)

  2. A Stretchable Alternating Current Electroluminescent Fiber

    Directory of Open Access Journals (Sweden)

    Dan Hu

    2018-01-01

    Full Text Available Flexible, stretchable electroluminescent fibers are of significance to meet the escalating requirements of increasing complexity and multifunctionality of smart electronics. We report a stretchable alternating current electroluminescent (ACEL fiber by a low-cost and all solution-processed scalable process. The ACEL fiber provides high stretchability, decent light-emitting performance, with excellent stability and nearly zero hysteresis. It can be stretched up to 80% strain. Our ACEL fiber device maintained a stable luminance for over 6000 stretch-release cycles at 50% strain. The mechanical stretchability and optical stability of our ACEL fiber device provides new possibilities towards next-generation stretchable displays, electronic textiles, advanced biomedical imaging and lighting, conformable visual readouts in arbitrary shapes, and novel health-monitoring devices.

  3. Carbon Nanotube Flexible and Stretchable Electronics.

    Science.gov (United States)

    Cai, Le; Wang, Chuan

    2015-12-01

    The low-cost and large-area manufacturing of flexible and stretchable electronics using printing processes could radically change people's perspectives on electronics and substantially expand the spectrum of potential applications. Examples range from personalized wearable electronics to large-area smart wallpapers and from interactive bio-inspired robots to implantable health/medical apparatus. Owing to its one-dimensional structure and superior electrical property, carbon nanotube is one of the most promising material platforms for flexible and stretchable electronics. Here in this paper, we review the recent progress in this field. Applications of single-wall carbon nanotube networks as channel semiconductor in flexible thin-film transistors and integrated circuits, as stretchable conductors in various sensors, and as channel material in stretchable transistors will be discussed. Lastly, state-of-the-art advancement on printing process, which is ideal for large-scale fabrication of flexible and stretchable electronics, will also be reviewed in detail.

  4. Nanoporous Polymeric Grating-Based Optical Biosensors (Preprint)

    National Research Council Canada - National Science Library

    Hsiao, Vincent K; Waldeisen, John R; Lloyd, Pamela F; Bunning, Timothy J; Huang, Tony J

    2007-01-01

    .... The fabrication process of the nanoporous polymeric grating involves holographic interference patterning and a functionalized pre-polymer syrup that facilitates the immobilization of biomolecules...

  5. Nanoporous Polymeric Grating-Based Biosensors

    KAUST Repository

    Gao, Tieyu

    2012-05-02

    We demonstrate the utilization of an interferometrically created nanoporous polymeric gratings as a platform for biosensing applications. Aminopropyltriethoxysilane (APTES)-functionalized nanoporous polymeric gratings was fabricated by combining holographic interference patterning and APTES-functionalization of pre-polymer syrup. The successful detection of multiple biomolecules indicates that the biofunctionalized nanoporous polymeric gratings can act as biosensing platforms which are label-free, inexpensive, and applicable as high-throughput assays. Copyright © 2010 by ASME.

  6. Nanoporous Polymeric Grating-Based Biosensors

    KAUST Repository

    Gao, Tieyu; Hsiao, Vincent; Zheng, Yue Bing; Huang, Tony Jun

    2012-01-01

    We demonstrate the utilization of an interferometrically created nanoporous polymeric gratings as a platform for biosensing applications. Aminopropyltriethoxysilane (APTES)-functionalized nanoporous polymeric gratings was fabricated by combining holographic interference patterning and APTES-functionalization of pre-polymer syrup. The successful detection of multiple biomolecules indicates that the biofunctionalized nanoporous polymeric gratings can act as biosensing platforms which are label-free, inexpensive, and applicable as high-throughput assays. Copyright © 2010 by ASME.

  7. Conductive Elastomers for Stretchable Electronics, Sensors and Energy Harvesters

    Directory of Open Access Journals (Sweden)

    Jin-Seo Noh

    2016-04-01

    Full Text Available There have been a wide variety of efforts to develop conductive elastomers that satisfy both mechanical stretchability and electrical conductivity, as a response to growing demands on stretchable and wearable devices. This article reviews the important progress in conductive elastomers made in three application fields of stretchable technology: stretchable electronics, stretchable sensors, and stretchable energy harvesters. Diverse combinations of insulating elastomers and non-stretchable conductive materials have been studied to realize optimal conductive elastomers. It is noted that similar material combinations and similar structures have often been employed in different fields of application. In terms of stretchability, cyclic operation, and overall performance, fields such as stretchable conductors and stretchable strain/pressure sensors have achieved great advancement, whereas other fields like stretchable memories and stretchable thermoelectric energy harvesting are in their infancy. It is worth mentioning that there are still obstacles to overcome for the further progress of stretchable technology in the respective fields, which include the simplification of material combination and device structure, securement of reproducibility and reliability, and the establishment of easy fabrication techniques. Through this review article, both the progress and obstacles associated with the respective stretchable technologies will be understood more clearly.

  8. Optical fiber sensors embedded in flexible polymer foils

    Science.gov (United States)

    van Hoe, Bram; van Steenberge, Geert; Bosman, Erwin; Missinne, Jeroen; Geernaert, Thomas; Berghmans, Francis; Webb, David; van Daele, Peter

    2010-04-01

    In traditional electrical sensing applications, multiplexing and interconnecting the different sensing elements is a major challenge. Recently, many optical alternatives have been investigated including optical fiber sensors of which the sensing elements consist of fiber Bragg gratings. Different sensing points can be integrated in one optical fiber solving the interconnection problem and avoiding any electromagnetical interference (EMI). Many new sensing applications also require flexible or stretchable sensing foils which can be attached to or wrapped around irregularly shaped objects such as robot fingers and car bumpers or which can even be applied in biomedical applications where a sensor is fixed on a human body. The use of these optical sensors however always implies the use of a light-source, detectors and electronic circuitry to be coupled and integrated with these sensors. The coupling of these fibers with these light sources and detectors is a critical packaging problem and as it is well-known the costs for packaging, especially with optoelectronic components and fiber alignment issues are huge. The end goal of this embedded sensor is to create a flexible optical sensor integrated with (opto)electronic modules and control circuitry. To obtain this flexibility, one can embed the optical sensors and the driving optoelectronics in a stretchable polymer host material. In this article different embedding techniques for optical fiber sensors are described and characterized. Initial tests based on standard manufacturing processes such as molding and laser structuring are reported as well as a more advanced embedding technique based on soft lithography processing.

  9. Stretchable bioelectronics for medical devices and systems

    CERN Document Server

    Ghaffari, Roozbeh; Kim, Dae-Hyeong

    2016-01-01

    This book highlights recent advances in soft and stretchable biointegrated electronics. A renowned group of authors address key ideas in the materials, processes, mechanics, and devices of soft and stretchable electronics; the wearable electronics systems; and bioinspired and implantable biomedical electronics. Among the topics discussed are liquid metals, stretchable and flexible energy sources, skin-like devices, in vitro neural recording, and more. Special focus is given to recent advances in extremely soft and stretchable bio-inspired electronics with real-world clinical studies that validate the technology. Foundational theoretical and experimental aspects are also covered in relation to the design and application of these biointegrated electronics systems. This is an ideal book for researchers, engineers, and industry professionals involved in developing healthcare devices, medical tools and related instruments relevant to various clinical practices.

  10. Flexible and Stretchable Microneedle Patches with Integrated Rigid Stainless Steel Microneedles for Transdermal Biointerfacing.

    Science.gov (United States)

    Rajabi, Mina; Roxhed, Niclas; Shafagh, Reza Zandi; Haraldson, Tommy; Fischer, Andreas Christin; Wijngaart, Wouter van der; Stemme, Göran; Niklaus, Frank

    2016-01-01

    This paper demonstrates flexible and stretchable microneedle patches that combine soft and flexible base substrates with hard and sharp stainless steel microneedles. An elastomeric polymer base enables conformal contact between the microneedle patch and the complex topography and texture of the underlying skin, while robust and sharp stainless steel microneedles reliably pierce the outer layers of the skin. The flexible microneedle patches have been realized by magnetically assembling short stainless steel microneedles into a flexible polymer supporting base. In our experimental investigation, the microneedle patches were applied to human skin and an excellent adaptation of the patch to the wrinkles and deformations of the skin was verified, while at the same time the microneedles reliably penetrate the surface of the skin. The unobtrusive flexible and stretchable microneedle patches have great potential for transdermal biointerfacing in a variety of emerging applications such as transdermal drug delivery, bioelectric treatments and wearable bio-electronics for health and fitness monitoring.

  11. Stretchable Random Lasers with Tunable Coherent Loops.

    Science.gov (United States)

    Sun, Tzu-Min; Wang, Cih-Su; Liao, Chi-Shiun; Lin, Shih-Yao; Perumal, Packiyaraj; Chiang, Chia-Wei; Chen, Yang-Fang

    2015-12-22

    Stretchability represents a key feature for the emerging world of realistic applications in areas, including wearable gadgets, health monitors, and robotic skins. Many optical and electronic technologies that can respond to large strain deformations have been developed. Laser plays a very important role in our daily life since it was discovered, which is highly desirable for the development of stretchable devices. Herein, stretchable random lasers with tunable coherent loops are designed, fabricated, and demonstrated. To illustrate our working principle, the stretchable random laser is made possible by transferring unique ZnO nanobrushes on top of polydimethylsiloxane (PDMS) elastomer substrate. Apart from the traditional gain material of ZnO nanorods, ZnO nanobrushes were used as optical gain materials so they can serve as scattering centers and provide the Fabry-Perot cavity to enhance laser action. The stretchable PDMS substrate gives the degree of freedom to mechanically tune the coherent loops of the random laser action by changing the density of ZnO nanobrushes. It is found that the number of laser modes increases with increasing external strain applied on the PDMS substrate due to the enhanced possibility for the formation of coherent loops. The device can be stretched by up to 30% strain and subjected to more than 100 cycles without loss in laser action. The result shows a major advance for the further development of man-made smart stretchable devices.

  12. Flexible and stretchable lithium-ion batteries and supercapacitors based on electrically conducting carbon nanotube fiber springs.

    Science.gov (United States)

    Zhang, Ye; Bai, Wenyu; Cheng, Xunliang; Ren, Jing; Weng, Wei; Chen, Peining; Fang, Xin; Zhang, Zhitao; Peng, Huisheng

    2014-12-22

    The construction of lightweight, flexible and stretchable power systems for modern electronic devices without using elastic polymer substrates is critical but remains challenging. We have developed a new and general strategy to produce both freestanding, stretchable, and flexible supercapacitors and lithium-ion batteries with remarkable electrochemical properties by designing novel carbon nanotube fiber springs as electrodes. These springlike electrodes can be stretched by over 300 %. In addition, the supercapacitors and lithium-ion batteries have a flexible fiber shape that enables promising applications in electronic textiles. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. DEA deformed stretchable patch antenna

    International Nuclear Information System (INIS)

    Jiang, X-J; Jalali Mazlouman, S; Menon, C; Mahanfar, A; Vaughan, R G

    2012-01-01

    A stretchable patch antenna (SPA) whose frequency is tuned by a planar dielectric elastomer actuator (DEA) is presented in this paper. This mechanically reconfigurable antenna system has a configuration resembling a pre-stretched silicone belt. Part of the belt is embedded with a layer of conductive liquid metal to form the patch antenna. Part of the belt is sandwiched between conductive electrodes to form the DEA. Electrical activation of the DEA results in a contraction of the patch antenna, and as a result, in a variation of its resonance frequency. Design and fabrication steps of this system are presented. Measurement results for deformation, resonance frequency variation and efficiency of the patch antenna are also presented. (paper)

  14. Fully Printed Flexible and Stretchable Electronics

    Science.gov (United States)

    Zhang, Suoming

    Through this thesis proposal, the author has demonstrated series of flexible or stretchable sensors including strain gauge, pressure sensors, display arrays, thin film transistors and photodetectors fabricated by a direct printing process. By adopting the novel serpentine configuration with conventional non-stretchable materials silver nanoparticles, the fully printed stretchable devices are successfully fabricated on elastomeric substrate with the demonstration of stretchable conductors that can maintain the electrical properties under strain and the strain gauge, which could be used to measure the strain in desired locations and also to monitor individual person's finger motion. And by investigating the intrinsic stretchable materials silver nanowires (AgNWs) with the conventional configuration, the fully printed stretchable conductors are achieved on various substrates including Si, glass, Polyimide, Polydimethylsiloxane (PDMS) and Very High Bond (VHB) tape with the illustration of the capacitive pressure sensor and stretchable electroluminescent displays. In addition, intrinsically stretchable thin-film transistors (TFTs) and integrated logic circuits are directly printed on elastomeric PDMS substrates. The printed devices utilize carbon nanotubes and a type of hybrid gate dielectric comprising PDMS and barium titanate (BaTiO3) nanoparticles. The BaTiO3/PDMS composite simultaneously provides high dielectric constant, superior stretchability, low leakage, as well as good printability and compatibility with the elastomeric substrate. Both TFTs and logic circuits can be stretched beyond 50% strain along either channel length or channel width directions for thousands of cycles while showing no significant degradation in electrical performance. Finally, by applying the SWNTs as the channel layer of the thin film transistor, we successfully fabricate the fully printed flexible photodetector which exhibits good electrical characteristics and the transistors exhibit

  15. Inverse-designed stretchable metalens with tunable focal distance

    Science.gov (United States)

    Callewaert, Francois; Velev, Vesselin; Jiang, Shizhou; Sahakian, Alan Varteres; Kumar, Prem; Aydin, Koray

    2018-02-01

    In this paper, we present an inverse-designed 3D-printed all-dielectric stretchable millimeter wave metalens with a tunable focal distance. A computational inverse-design method is used to design a flat metalens made of disconnected polymer building blocks with complex shapes, as opposed to conventional monolithic lenses. The proposed metalens provides better performance than a conventional Fresnel lens, using lesser amount of material and enabling larger focal distance tunability. The metalens is fabricated using a commercial 3D-printer and attached to a stretchable platform. Measurements and simulations show that the focal distance can be tuned by a factor of 4 with a stretching factor of only 75%, a nearly diffraction-limited focal spot, and with a 70% relative focusing efficiency, defined as the ratio between power focused in the focal spot and power going through the focal plane. The proposed platform can be extended for design and fabrication of multiple electromagnetic devices working from visible to microwave radiation depending on scaling of the devices.

  16. A highly stretchable autonomous self-healing elastomer

    Science.gov (United States)

    Li, Cheng-Hui; Wang, Chao; Keplinger, Christoph; Zuo, Jing-Lin; Jin, Lihua; Sun, Yang; Zheng, Peng; Cao, Yi; Lissel, Franziska; Linder, Christian; You, Xiao-Zeng; Bao, Zhenan

    2016-06-01

    It is a challenge to synthesize materials that possess the properties of biological muscles—strong, elastic and capable of self-healing. Herein we report a network of poly(dimethylsiloxane) polymer chains crosslinked by coordination complexes that combines high stretchability, high dielectric strength, autonomous self-healing and mechanical actuation. The healing process can take place at a temperature as low as -20 °C and is not significantly affected by surface ageing and moisture. The crosslinking complexes used consist of 2,6-pyridinedicarboxamide ligands that coordinate to Fe(III) centres through three different interactions: a strong pyridyl-iron one, and two weaker carboxamido-iron ones through both the nitrogen and oxygen atoms of the carboxamide groups. As a result, the iron-ligand bonds can readily break and re-form while the iron centres still remain attached to the ligands through the stronger interaction with the pyridyl ring, which enables reversible unfolding and refolding of the chains. We hypothesize that this behaviour supports the high stretchability and self-healing capability of the material.

  17. Stretchable and High-Performance Supercapacitors with Crumpled Graphene Papers

    OpenAIRE

    Zang, Jianfeng; Cao, Changyong; Feng, Yaying; Liu, Jie; Zhao, Xuanhe

    2014-01-01

    Fabrication of unconventional energy storage devices with high stretchability and performance is challenging, but critical to practical operations of fully power-independent stretchable electronics. While supercapacitors represent a promising candidate for unconventional energy-storage devices, existing stretchable supercapacitors are limited by their low stretchability, complicated fabrication process, and high cost. Here, we report a simple and low-cost method to fabricate extremely stretch...

  18. Mogul-Patterned Elastomeric Substrate for Stretchable Electronics.

    Science.gov (United States)

    Lee, Han-Byeol; Bae, Chan-Wool; Duy, Le Thai; Sohn, Il-Yung; Kim, Do-Il; Song, You-Joon; Kim, Youn-Jea; Lee, Nae-Eung

    2016-04-01

    A mogul-patterned stretchable substrate with multidirectional stretchability and minimal fracture of layers under high stretching is fabricated by double photolithography and soft lithography. Au layers and a reduced graphene oxide chemiresistor on a mogul-patterned poly(dimethylsiloxane) substrate are stable and durable under various stretching conditions. The newly designed mogul-patterned stretchable substrate shows great promise for stretchable electronics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Ag/Au/Polypyrrole Core-shell Nanowire Network for Transparent, Stretchable and Flexible Supercapacitor in Wearable Energy Devices

    OpenAIRE

    Moon, Hyunjin; Lee, Habeom; Kwon, Jinhyeong; Suh, Young Duk; Kim, Dong Kwan; Ha, Inho; Yeo, Junyeob; Hong, Sukjoon; Ko, Seung Hwan

    2017-01-01

    Transparent and stretchable energy storage devices have attracted significant interest due to their potential to be applied to biocompatible and wearable electronics. Supercapacitors that use the reversible faradaic redox reaction of conducting polymer have a higher specific capacitance as compared with electrical double-layer capacitors. Typically, the conducting polymer electrode is fabricated through direct electropolymerization on the current collector. However, no research have been cond...

  20. Mechanics and thermal management of stretchable inorganic electronics.

    Science.gov (United States)

    Song, Jizhou; Feng, Xue; Huang, Yonggang

    2016-03-01

    Stretchable electronics enables lots of novel applications ranging from wearable electronics, curvilinear electronics to bio-integrated therapeutic devices that are not possible through conventional electronics that is rigid and flat in nature. One effective strategy to realize stretchable electronics exploits the design of inorganic semiconductor material in a stretchable format on an elastomeric substrate. In this review, we summarize the advances in mechanics and thermal management of stretchable electronics based on inorganic semiconductor materials. The mechanics and thermal models are very helpful in understanding the underlying physics associated with these systems, and they also provide design guidelines for the development of stretchable inorganic electronics.

  1. Mechanics and thermal management of stretchable inorganic electronics

    Science.gov (United States)

    Song, Jizhou; Feng, Xue; Huang, Yonggang

    2016-01-01

    Stretchable electronics enables lots of novel applications ranging from wearable electronics, curvilinear electronics to bio-integrated therapeutic devices that are not possible through conventional electronics that is rigid and flat in nature. One effective strategy to realize stretchable electronics exploits the design of inorganic semiconductor material in a stretchable format on an elastomeric substrate. In this review, we summarize the advances in mechanics and thermal management of stretchable electronics based on inorganic semiconductor materials. The mechanics and thermal models are very helpful in understanding the underlying physics associated with these systems, and they also provide design guidelines for the development of stretchable inorganic electronics. PMID:27547485

  2. Self-similar and fractal design for stretchable electronics

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, John A.; Fan, Jonathan; Yeo, Woon-Hong; Su, Yewang; Huang, Yonggang; Zhang, Yihui

    2017-04-04

    The present invention provides electronic circuits, devices and device components including one or more stretchable components, such as stretchable electrical interconnects, electrodes and/or semiconductor components. Stretchability of some of the present systems is achieved via a materials level integration of stretchable metallic or semiconducting structures with soft, elastomeric materials in a configuration allowing for elastic deformations to occur in a repeatable and well-defined way. The stretchable device geometries and hard-soft materials integration approaches of the invention provide a combination of advance electronic function and compliant mechanics supporting a broad range of device applications including sensing, actuation, power storage and communications.

  3. Fiber Optic Bragg Gratings

    National Research Council Canada - National Science Library

    Battiato, James

    1998-01-01

    Coupled mode theory was used to model reflection fiber gratings. The effects of experimental parameters on grating characteristics were modeled for both uniform and non-uniform grating profiles using this approach...

  4. Realization of Intrinsically Stretchable Organic Solar Cells Enabled by Charge-Extraction Layer and Photoactive Material Engineering.

    Science.gov (United States)

    Hsieh, Yun-Ting; Chen, Jung-Yao; Fukuta, Seijiro; Lin, Po-Chen; Higashihara, Tomoya; Chueh, Chu-Chen; Chen, Wen-Chang

    2018-06-12

    The rapid development of wearable electronic devices has prompted a strong demand to develop stretchable organic solar cells (OSCs) to serve as the advanced powering systems. However, to realize an intrinsically stretchable OSC is challenging because it requires all the constituent layers to possess certain elastic properties. It thus necessitates a combined engineering of charge-transporting layers and photoactive materials. Herein, we first describe a stretchable electron-extraction layer using a blend of poly[(9,9-bis(3'-( N, N-dimethylamino)propyl)-2,7-fluorene)- alt-2,7-(9,9-dioctylfluorene)] (PFN) and nitrile butadiene rubber (NBR, Nipol 1072). This hybrid PFN/NBR layer exhibits a much lower Derjaguin-Muller-Toporov modulus (0.45 GPa) than the value (1.25 GPa) of the pristine PFN and could withstand a high strain (60% strain) without showing any cracks. Moreover, besides enriching the stretchability of PFN, the terminal carboxyl groups of NBR can ionize PFN to promote its solution-processability in polar solvents and to ensure the interfacial dipole formation at the corresponding interface in the device, as evidenced by the Fourier transform infrared and ultraviolet photoelectron spectroscopy analyses. By further coupling the replacement of [6,6]-phenyl-C 61 -butyric acid methyl ester (PCBM) with nonfullerene acceptors owing to better mechanical stretchability in the photoactive layer, OSCs with improved intrinsically stretchability and performance were demonstrated. An all-polymer OSC can exhibit a power conversion efficiency of 2.82% after 10% stretching, surpassing the PCBM-based device that can only withstand 5% strain.

  5. Corrugated grating on organic multilayer Bragg reflector

    Science.gov (United States)

    Jaquet, Sylvain; Scharf, Toralf; Herzig, Hans Peter

    2007-08-01

    Polymeric multilayer Bragg structures are combined with diffractive gratings to produce artificial visual color effects. A particular effect is expected due to the angular reflection dependence of the multilayer Bragg structure and the dispersion caused by the grating. The combined effects can also be used to design particular filter functions and various resonant structures. The multilayer Bragg structure is fabricated by spin-coating of two different low-cost polymer materials in solution on a cleaned glass substrate. These polymers have a refractive index difference of about 0.15 and permit multilayer coatings without interlayer problems. Master gratings of different periods are realized by laser beam interference and replicated gratings are superimposed on the multilayer structure by soft embossing in a UV curing glue. The fabrication process requires only polymer materials. The obtained devices are stable and robust. Angular dependent reflection spectrums for the visible are measured. These results show that it is possible to obtain unexpected reflection effects. A rich variety of color spectra can be generated, which is not possible with a single grating. This can be explained by the coupling of transmission of grating orders and the Bragg reflection band. A simple model permits to explain some of the spectral vs angular dependence of reflected light.

  6. Elastically stretchable thin film conductors on an elastomeric substrate

    Science.gov (United States)

    Jones Harris, Joyelle Elizabeth

    Imagine a large, flat screen television that can be rolled into a small cylinder after purchase in the store and then unrolled and mounted onto the wall of a home. The electronic devices within the television must be able to withstand large deformation and tensile strain. Consider a robot that is covered with an electronic skin that simulates human skin. The skin would enable the machine to lift an elderly person with care and sensitivity. The skin will endure repeated deformation with the highest tensile strains being experienced at the robot's joints. These applications and many others will benefit from stretchable electronic circuitry. While several different methods have been employed to create stretchable electronics, all methods use a common tool -- stretchable conductors. Therefore, the goal of this thesis work was to fabricate elastically stretchable conductors that can be used in stretchable electronics. We deposited Au thin films on an elastomeric substrate, and the resulting conductors remained electrically continuous when stretched by 30% and more. We developed photolithographic processes that can be used to pattern elastically stretchable conductors with a 10 mum resolution. We fabricated bi-level stretchable conductors that are separated by an elastomeric insulator and are electrically connected through via holes in the insulator. We applied our bi-level conductors to create a stretchable resistor-inductor-capacitor (RLC) circuit with a tunable resonant frequency. We also used stretchable conductors to measure action potentials in biological samples. This thesis describes the fabrication and application of our elastically stretchable conductors.

  7. Mechanics of ultra-stretchable self-similar serpentine interconnects

    International Nuclear Information System (INIS)

    Zhang, Yihui; Fu, Haoran; Su, Yewang; Xu, Sheng

    2013-01-01

    Graphical abstract: We developed analytical models of flexibility and elastic-stretchability for self-similar interconnect. The analytic solutions agree very well with the finite element analyses, both demonstrating that the elastic-stretchability more than doubles when the order of self-similar structure increases by one. Design optimization yields 90% and 50% elastic stretchability for systems with surface filling ratios of 50% and 70% of active devices, respectively. The analytic models are useful for the development of stretchable electronics that simultaneously demand large coverage of active devices, such as stretchable photovoltaics and electronic eye-ball cameras. -- Abstract: Electrical interconnects that adopt self-similar, serpentine layouts offer exceptional levels of stretchability in systems that consist of collections of small, non-stretchable active devices in the so-called island–bridge design. This paper develops analytical models of flexibility and elastic stretchability for such structures, and establishes recursive formulae at different orders of self-similarity. The analytic solutions agree well with finite element analysis, with both demonstrating that the elastic stretchability more than doubles when the order of the self-similar structure increases by one. Design optimization yields 90% and 50% elastic stretchability for systems with surface filling ratios of 50% and 70% of active devices, respectively

  8. From stretchable to reconfigurable inorganic electronics

    KAUST Repository

    Nassar, Joanna M.

    2016-05-06

    Today’s state-of-the-art electronics are high performing, energy efficient, multi-functional and cost effective. However, they are also typically rigid and brittle. With the emergence of the Internet of Everything, electronic applications are expanding into previously unexplored areas, like healthcare, smart wearable artifacts, and robotics. One major challenge is the physical asymmetry of target application surfaces, which often cause mechanical stretching, contracting, twisting and other deformations to the application. In this review paper, we explore materials, processes, mechanics and devices that enable physically stretchable and reconfigurable electronics. While the concept of stretchable electronics is commonly used in practice, the notion of physically reconfigurable electronics is still in its infancy. Because organic materials are commonly naturally stretchable and physically deformable, we predominantly focus on electronics made from inorganic materials that have the capacity for physical stretching and reconfiguration while retaining their intended attributes. We emphasize how applications of electronics dictate theory to integration strategy for stretchable and reconfigurable inorganic electronics.

  9. Highly Stretchable, Strain Sensing Hydrogel Optical Fibers.

    Science.gov (United States)

    Guo, Jingjing; Liu, Xinyue; Jiang, Nan; Yetisen, Ali K; Yuk, Hyunwoo; Yang, Changxi; Khademhosseini, Ali; Zhao, Xuanhe; Yun, Seok-Hyun

    2016-12-01

    A core-clad fiber made of elastic, tough hydrogels is highly stretchable while guiding light. Fluorescent dyes are easily doped into the hydrogel fiber by diffusion. When stretched, the transmission spectrum of the fiber is altered, enabling the strain to be measured and also its location. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Gravitational Grating

    Science.gov (United States)

    Rahvar, Sohrab

    2018-05-01

    In this work, we study the interaction of the electromagnetic wave (EW) from a distant quasar with the gravitational wave (GW) sourced by the binary stars. While in the regime of geometric optics, the light bending due to this interaction is negligible, we show that the phase shifting on the wavefront of an EW can produce the diffraction pattern on the observer plane. The diffraction of the light (with the wavelength of λe) by the gravitational wave playing the role of gravitational grating (with the wavelength of λg) has the diffraction angle of Δβ ˜ λe/λg. The relative motion of the observer, the source of gravitational wave and the quasar results in a relative motion of the observer through the interference pattern on the observer plane. The consequence of this fringe crossing is the modulation in the light curve of a quasar with the period of few hours in the microwave wavelength. The optical depth for the observation of this phenomenon for a Quasar with the multiple images strongly lensed by a galaxy where the light trajectory of some of the images crosses the lensing galaxy is τ ≃ 0.2. By shifting the time-delay of the light curves of the multiple images in a strong lensed quasar and removing the intrinsic variations of a quasar, our desired signals, as a new method for detection of GWs can be detected.

  11. Fractal design concepts for stretchable electronics.

    Science.gov (United States)

    Fan, Jonathan A; Yeo, Woon-Hong; Su, Yewang; Hattori, Yoshiaki; Lee, Woosik; Jung, Sung-Young; Zhang, Yihui; Liu, Zhuangjian; Cheng, Huanyu; Falgout, Leo; Bajema, Mike; Coleman, Todd; Gregoire, Dan; Larsen, Ryan J; Huang, Yonggang; Rogers, John A

    2014-01-01

    Stretchable electronics provide a foundation for applications that exceed the scope of conventional wafer and circuit board technologies due to their unique capacity to integrate with soft materials and curvilinear surfaces. The range of possibilities is predicated on the development of device architectures that simultaneously offer advanced electronic function and compliant mechanics. Here we report that thin films of hard electronic materials patterned in deterministic fractal motifs and bonded to elastomers enable unusual mechanics with important implications in stretchable device design. In particular, we demonstrate the utility of Peano, Greek cross, Vicsek and other fractal constructs to yield space-filling structures of electronic materials, including monocrystalline silicon, for electrophysiological sensors, precision monitors and actuators, and radio frequency antennas. These devices support conformal mounting on the skin and have unique properties such as invisibility under magnetic resonance imaging. The results suggest that fractal-based layouts represent important strategies for hard-soft materials integration.

  12. Ferrofluid-based Stretchable Magnetic Core Inductors

    Science.gov (United States)

    Lazarus, N.; Meyer, C. D.

    2015-12-01

    Magnetic materials are commonly used in inductor and transformer cores to increase inductance density. The emerging field of stretchable electronics poses a new challenge since typical magnetic cores are bulky, rigid and often brittle. This paper presents, for the first time, stretchable inductors incorporating ferrofluid as a liquid magnetic core. Ferrofluids, suspensions of nanoscale magnetic particles in a carrier liquid, provide enhanced magnetic permeability without changing the mechanical properties of the surrounding elastomer. The inductor tested in this work consisted of a liquid metal solenoid wrapped around a ferrofluid core in separate channels. The low frequency inductance was found to increase from 255 nH before fill to 390 nH after fill with ferrofluid, an increase of 52%. The inductor was also shown to survive uniaxial strains of up to 100%.

  13. Stretchable inductor with liquid magnetic core

    Science.gov (United States)

    Lazarus, N.; Meyer, C. D.

    2016-03-01

    Adding magnetic materials is a well-established method for improving performance of inductors. However, traditional magnetic cores are rigid and poorly suited for the emerging field of stretchable electronics, where highly deformable inductors are used to wirelessly couple power and data signals. In this work, stretchable inductors are demonstrated based on the use of ferrofluids, magnetic liquids based on distributed magnetic particles, to create a compliant magnetic core. Using a silicone molding technique to create multi-layer fluidic channels, a liquid metal solenoid is fabricated around a ferrofluid channel. An analytical model is developed for the effects of mechanical strain, followed by experimental verification using two different ferrofluids with different permeabilities. Adding ferrofluid was found to increase the unstrained inductance by up to 280% relative to a similar inductor with a non-magnetic silicone core, while retaining the ability to survive uniaxial strains up to 100%.

  14. Fractal design concepts for stretchable electronics

    Science.gov (United States)

    Fan, Jonathan A.; Yeo, Woon-Hong; Su, Yewang; Hattori, Yoshiaki; Lee, Woosik; Jung, Sung-Young; Zhang, Yihui; Liu, Zhuangjian; Cheng, Huanyu; Falgout, Leo; Bajema, Mike; Coleman, Todd; Gregoire, Dan; Larsen, Ryan J.; Huang, Yonggang; Rogers, John A.

    2014-02-01

    Stretchable electronics provide a foundation for applications that exceed the scope of conventional wafer and circuit board technologies due to their unique capacity to integrate with soft materials and curvilinear surfaces. The range of possibilities is predicated on the development of device architectures that simultaneously offer advanced electronic function and compliant mechanics. Here we report that thin films of hard electronic materials patterned in deterministic fractal motifs and bonded to elastomers enable unusual mechanics with important implications in stretchable device design. In particular, we demonstrate the utility of Peano, Greek cross, Vicsek and other fractal constructs to yield space-filling structures of electronic materials, including monocrystalline silicon, for electrophysiological sensors, precision monitors and actuators, and radio frequency antennas. These devices support conformal mounting on the skin and have unique properties such as invisibility under magnetic resonance imaging. The results suggest that fractal-based layouts represent important strategies for hard-soft materials integration.

  15. Neutron diffraction from holographic gratings in PMMA

    International Nuclear Information System (INIS)

    Havermeyer, F.; Kraetzig, E.; Rupp, R.A.; Schubert, D.W.

    1999-01-01

    Complete text of publication follows. By definition photorefractive materials change the refractive index for light under the action of light. Using the spatially modulated light intensity pattern from the interference of two plane waves, volume phase gratings with accurately defined spacings can be produced. Depending on the material there are many physical origins for these gratings, but in most cases they are linked to a density modulation and, consequently, to a refractive index grating for neutrons. By diffraction of light or neutrons from such gratings even small refractive index changes down to Δn ∼ 10 -7 - 10 -9 can be measured. In our photopolymer system PMMA/MMA (poly(methyl methacrylate) with a content of 10-20% of the residual monomer methyl methacrylate) inhomogeneous illumination leads to local post-polymerisation processes of the residual monomer. The resulting light-optical refractive index grating is caused by the modulation of the monomer/polymer ratio as well as by the modulation of the total density. Only by the unique combination of methods for light and neutron diffraction, available at HOLONS (Holography and Neutron Scattering, instrument at the GKSS research centre), both contributions can be separated. We discuss the angular dependence of the neutron diffraction efficiency for weakly and strongly (efficiencies up to 60% have been achieved) modulated gratings and propose a simple model for the evaluation of the gratings. (author)

  16. Stretchable and Soft Electronics using Liquid Metals.

    Science.gov (United States)

    Dickey, Michael D

    2017-07-01

    The use of liquid metals based on gallium for soft and stretchable electronics is discussed. This emerging class of electronics is motivated, in part, by the new opportunities that arise from devices that have mechanical properties similar to those encountered in the human experience, such as skin, tissue, textiles, and clothing. These types of electronics (e.g., wearable or implantable electronics, sensors for soft robotics, e-skin) must operate during deformation. Liquid metals are compelling materials for these applications because, in principle, they are infinitely deformable while retaining metallic conductivity. Liquid metals have been used for stretchable wires and interconnects, reconfigurable antennas, soft sensors, self-healing circuits, and conformal electrodes. In contrast to Hg, liquid metals based on gallium have low toxicity and essentially no vapor pressure and are therefore considered safe to handle. Whereas most liquids bead up to minimize surface energy, the presence of a surface oxide on these metals makes it possible to pattern them into useful shapes using a variety of techniques, including fluidic injection and 3D printing. In addition to forming excellent conductors, these metals can be used actively to form memory devices, sensors, and diodes that are completely built from soft materials. The properties of these materials, their applications within soft and stretchable electronics, and future opportunities and challenges are considered. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Stretchable Triboelectric-Photonic Smart Skin for Tactile and Gesture Sensing.

    Science.gov (United States)

    Bu, Tianzhao; Xiao, Tianxiao; Yang, Zhiwei; Liu, Guoxu; Fu, Xianpeng; Nie, Jinhui; Guo, Tong; Pang, Yaokun; Zhao, Junqing; Xi, Fengben; Zhang, Chi; Wang, Zhong Lin

    2018-04-01

    Smart skin is expected to be stretchable and tactile for bionic robots as the medium with the ambient environment. Here, a stretchable triboelectric-photonic smart skin (STPS) is reported that enables multidimensional tactile and gesture sensing for a robotic hand. With a grating-structured metal film as the bioinspired skin stripe, the STPS exhibits a tunable aggregation-induced emission in a lateral tensile range of 0-160%. Moreover, the STPS can be used as a triboelectric nanogenerator for vertical pressure sensing with a maximum sensitivity of 34 mV Pa -1 . The pressure sensing characteristics can remain stable in different stretching conditions, which demonstrates a synchronous and independent sensing property for external stimuli with great durability. By integrating on a robotic hand as a conformal covering, the STPS shows multidimensional mechanical sensing abilities for external touch and different gestures with joints bending. This work has first demonstrated a triboelectric-photonic coupled multifunctional sensing terminal, which may have great applications in human-machine interaction, soft robots, and artificial intelligence. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. Ag/Au/Polypyrrole Core-shell Nanowire Network for Transparent, Stretchable and Flexible Supercapacitor in Wearable Energy Devices

    Science.gov (United States)

    Moon, Hyunjin; Lee, Habeom; Kwon, Jinhyeong; Suh, Young Duk; Kim, Dong Kwan; Ha, Inho; Yeo, Junyeob; Hong, Sukjoon; Ko, Seung Hwan

    2017-02-01

    Transparent and stretchable energy storage devices have attracted significant interest due to their potential to be applied to biocompatible and wearable electronics. Supercapacitors that use the reversible faradaic redox reaction of conducting polymer have a higher specific capacitance as compared with electrical double-layer capacitors. Typically, the conducting polymer electrode is fabricated through direct electropolymerization on the current collector. However, no research have been conducted on metal nanowires as current collectors for the direct electropolymerization, even though the metal nanowire network structure has proven to be superior as a transparent, flexible, and stretchable electrode platform because the conducting polymer’s redox potential for polymerization is higher than that of widely studied metal nanowires such as silver and copper. In this study, we demonstrated a highly transparent and stretchable supercapacitor by developing Ag/Au/Polypyrrole core-shell nanowire networks as electrode by coating the surface of Ag NWs with a thin layer of gold, which provide higher redox potential than the electropolymerizable monomer. The Ag/Au/Polypyrrole core-shell nanowire networks demonstrated superior mechanical stability under various mechanical bending and stretching. In addition, proposed supercapacitors showed fine optical transmittance together with fivefold improved areal capacitance compared to pristine Ag/Au core-shell nanowire mesh-based supercapacitors.

  19. Active resonance tuning of stretchable plasmonic structures

    DEFF Research Database (Denmark)

    Zhu, Xiaolong; Xiao, Sanshui; Mortensen, N. Asger

    2012-01-01

    Active resonance tuning is highly desired for the applications of plasmonic structures, such as optical switches and surface enhanced Raman substrates. In this paper, we demonstrate the active tunable plasmonic structures, which composed of monolayer arrays of metallic semishells with dielectric...... cores on stretchable elastic substrates. These composite structures support Bragg-type surface plasmon resonances whose frequencies are sensitive to the arrangement of the metallic semishells. Under uniaxial stretching, the lattice symmetry of these plasmonic structures can be reconfigured from...... applications of the stretch-tunable plasmonic structures in sensing, switching, and filtering....

  20. Miniaturized Stretchable and High-Rate Linear Supercapacitors

    Science.gov (United States)

    Zhu, Wenjun; Zhang, Yang; Zhou, Xiaoshuang; Xu, Jiang; Liu, Zunfeng; Yuan, Ningyi; Ding, Jianning

    2017-07-01

    Linear stretchable supercapacitors have attracted much attention because they are well suited to applications in the rapidly expanding field of wearable electronics. However, poor conductivity of the electrode material, which limits the transfer of electrons in the axial direction of the linear supercapacitors, leads to a serious loss of capacity at high rates. To solve this problem, we use gold nanoparticles to decorate aligned multiwall carbon nanotube to fabricate stretchable linear electrodes. Furthermore, we have developed fine stretchable linear supercapacitors, which exhibited an extremely high elasticity up to 400% strain with a high capacitance of about 8.7 F g-1 at the discharge current of 1 A g-1.

  1. Strain Multiplexed Metasurface Holograms on a Stretchable Substrate.

    Science.gov (United States)

    Malek, Stephanie C; Ee, Ho-Seok; Agarwal, Ritesh

    2017-06-14

    We demonstrate reconfigurable phase-only computer-generated metasurface holograms with up to three image planes operating in the visible regime fabricated with gold nanorods on a stretchable polydimethylsiloxane substrate. Stretching the substrate enlarges the hologram image and changes the location of the image plane. Upon stretching, these devices can switch the displayed holographic image between multiple distinct images. This work opens up the possibilities for stretchable metasurface holograms as flat devices for dynamically reconfigurable optical communication and display. It also confirms that metasurfaces on stretchable substrates can serve as platform for a variety of reconfigurable optical devices.

  2. Optical fibre Bragg grating recorded in TOPAS cyclic olefin copolymer

    DEFF Research Database (Denmark)

    Johnson, I.P.; Yuan, Scott Wu; Stefani, Alessio

    2011-01-01

    A report is presented on the inscription of a fibre Bragg grating into a microstructured polymer optical fibre fabricated from TOPAS cyclic olefin copolymer. This material offers two important advantages over poly (methyl methacrylate), which up to now has formed the basis for polymer fibre Bragg...

  3. Stretchable and foldable silicon-based electronics

    KAUST Repository

    Cavazos Sepulveda, Adrian Cesar

    2017-03-30

    Flexible and stretchable semiconducting substrates provide the foundation for novel electronic applications. Usually, ultra-thin, flexible but often fragile substrates are used in such applications. Here, we describe flexible, stretchable, and foldable 500-μm-thick bulk mono-crystalline silicon (100) “islands” that are interconnected via extremely compliant 30-μm-thick connectors made of silicon. The thick mono-crystalline segments create a stand-alone silicon array that is capable of bending to a radius of 130 μm. The bending radius of the array does not depend on the overall substrate thickness because the ultra-flexible silicon connectors are patterned. We use fracture propagation to release the islands. Because they allow for three-dimensional monolithic stacking of integrated circuits or other electronics without any through-silicon vias, our mono-crystalline islands can be used as a “more-than-Moore” strategy and to develop wearable electronics that are sufficiently robust to be compatible with flip-chip bonding.

  4. Stretchable and foldable silicon-based electronics

    KAUST Repository

    Cavazos Sepulveda, Adrian Cesar; Diaz Cordero, M. S.; Carreno, Armando Arpys Arevalo; Nassar, Joanna M.; Hussain, Muhammad Mustafa

    2017-01-01

    Flexible and stretchable semiconducting substrates provide the foundation for novel electronic applications. Usually, ultra-thin, flexible but often fragile substrates are used in such applications. Here, we describe flexible, stretchable, and foldable 500-μm-thick bulk mono-crystalline silicon (100) “islands” that are interconnected via extremely compliant 30-μm-thick connectors made of silicon. The thick mono-crystalline segments create a stand-alone silicon array that is capable of bending to a radius of 130 μm. The bending radius of the array does not depend on the overall substrate thickness because the ultra-flexible silicon connectors are patterned. We use fracture propagation to release the islands. Because they allow for three-dimensional monolithic stacking of integrated circuits or other electronics without any through-silicon vias, our mono-crystalline islands can be used as a “more-than-Moore” strategy and to develop wearable electronics that are sufficiently robust to be compatible with flip-chip bonding.

  5. Carbon doped PDMS: conductance stability over time and implications for additive manufacturing of stretchable electronics

    International Nuclear Information System (INIS)

    Tavakoli, Mahmoud; Rocha, Rui; Osorio, Luis; Almeida, Miguel; De Almeida, Anibal; Ramachandran, Vivek; Tabatabai, Arya; Lu, Tong; Majidi, Carmel

    2017-01-01

    Carbon doped PDMS (cPDMS), has been used as a conductive polymer for stretchable electronics. Compared to liquid metals, cPDMS is low cost and is easier to process or to print with an additive manufacturing process. However, changes on the conductance of the carbon based conductive PDMS (cPDMS) were observed over time, in particular after integration of cPDMS and the insulating polymer. In this article we investigate the process parameters that lead to improved stability over conductance of the cPDMS over time. Slight modifications to the fabrication process parameters were conducted and changes on the conductance of the samples for each method were monitored. Results suggested that change of the conductance happens mostly after integration of a pre-polymer over a cured cPDMS, and not after integration of the cPDMS over a cured insulating polymer. We show that such changes can be eliminated by adjusting the integration priority between the conductive and insulating polymers, by selecting the right curing temperature, changing the concentration of the carbon particles and the thickness of the conductive traces, and when possible by changing the insulating polymer material. In this way, we obtained important conclusions regarding the effect of these parameters on the change of the conductance over time, that should be considered for additive manufacturing of soft electronics. Also, we show that these changes can be possibly due to the diffusion from PDMS into cPDMS. (paper)

  6. Parallel Microcracks-based Ultrasensitive and Highly Stretchable Strain Sensors.

    Science.gov (United States)

    Amjadi, Morteza; Turan, Mehmet; Clementson, Cameron P; Sitti, Metin

    2016-03-02

    There is an increasing demand for flexible, skin-attachable, and wearable strain sensors due to their various potential applications. However, achieving strain sensors with both high sensitivity and high stretchability is still a grand challenge. Here, we propose highly sensitive and stretchable strain sensors based on the reversible microcrack formation in composite thin films. Controllable parallel microcracks are generated in graphite thin films coated on elastomer films. Sensors made of graphite thin films with short microcracks possess high gauge factors (maximum value of 522.6) and stretchability (ε ≥ 50%), whereas sensors with long microcracks show ultrahigh sensitivity (maximum value of 11,344) with limited stretchability (ε ≤ 50%). We demonstrate the high performance strain sensing of our sensors in both small and large strain sensing applications such as human physiological activity recognition, human body large motion capturing, vibration detection, pressure sensing, and soft robotics.

  7. Free form CMOS electronics: Physically flexible and stretchable

    KAUST Repository

    Hussain, Muhammad Mustafa; Rojas, Jhonathan Prieto; Sevilla, Galo T.; Hussain, Aftab M.; Ghoneim, Mohamed T.; Hanna, Amir; Kutbee, Arwa T.; Nassar, Joanna M.; Cruz, Melvin

    2015-01-01

    Free form (physically flexible and stretchable) electronics can be used for applications which are unexplored today due to the rigid and brittle nature of the state-of-the-art electronics. Therefore, we show integration strategy to rationally design

  8. Ultrasensitive, Stretchable Strain Sensors Based on Fragmented Carbon Nanotube Papers

    KAUST Repository

    Zhou, Jian; Yu, Hu; Xu, Xuezhu; Han, Fei; Lubineau, Gilles

    2017-01-01

    The development of strain sensors featuring both ultra high sensitivity and high stretchability is still a challenge. We demonstrate that strain sensors based on fragmented single-walled carbon nanotube (SWCNT) paper embedded in poly

  9. Miniaturized Stretchable and High-Rate Linear Supercapacitors

    OpenAIRE

    Zhu, Wenjun; Zhang, Yang; Zhou, Xiaoshuang; Xu, Jiang; Liu, Zunfeng; Yuan, Ningyi; Ding, Jianning

    2017-01-01

    Linear stretchable supercapacitors have attracted much attention because they are well suited to applications in the rapidly expanding field of wearable electronics. However, poor conductivity of the electrode material, which limits the transfer of electrons in the axial direction of the linear supercapacitors, leads to a serious loss of capacity at high rates. To solve this problem, we use gold nanoparticles to decorate aligned multiwall carbon nanotube to fabricate stretchable linear electr...

  10. Highly-stretchable 3D-architected Mechanical Metamaterials

    Science.gov (United States)

    Jiang, Yanhui; Wang, Qiming

    2016-09-01

    Soft materials featuring both 3D free-form architectures and high stretchability are highly desirable for a number of engineering applications ranging from cushion modulators, soft robots to stretchable electronics; however, both the manufacturing and fundamental mechanics are largely elusive. Here, we overcome the manufacturing difficulties and report a class of mechanical metamaterials that not only features 3D free-form lattice architectures but also poses ultrahigh reversible stretchability (strain > 414%), 4 times higher than that of the existing counterparts with the similar complexity of 3D architectures. The microarchitected metamaterials, made of highly stretchable elastomers, are realized through an additive manufacturing technique, projection microstereolithography, and its postprocessing. With the fabricated metamaterials, we reveal their exotic mechanical behaviors: Under large-strain tension, their moduli follow a linear scaling relationship with their densities regardless of architecture types, in sharp contrast to the architecture-dependent modulus power-law of the existing engineering materials; under large-strain compression, they present tunable negative-stiffness that enables ultrahigh energy absorption efficiencies. To harness their extraordinary stretchability and microstructures, we demonstrate that the metamaterials open a number of application avenues in lightweight and flexible structure connectors, ultraefficient dampers, 3D meshed rehabilitation structures and stretchable electronics with designed 3D anisotropic conductivity.

  11. Stretchable and High-Performance Supercapacitors with Crumpled Graphene Papers

    Science.gov (United States)

    Zang, Jianfeng; Cao, Changyong; Feng, Yaying; Liu, Jie; Zhao, Xuanhe

    2014-10-01

    Fabrication of unconventional energy storage devices with high stretchability and performance is challenging, but critical to practical operations of fully power-independent stretchable electronics. While supercapacitors represent a promising candidate for unconventional energy-storage devices, existing stretchable supercapacitors are limited by their low stretchability, complicated fabrication process, and high cost. Here, we report a simple and low-cost method to fabricate extremely stretchable and high-performance electrodes for supercapacitors based on new crumpled-graphene papers. Electrolyte-mediated-graphene paper bonded on a compliant substrate can be crumpled into self-organized patterns by harnessing mechanical instabilities in the graphene paper. As the substrate is stretched, the crumpled patterns unfold, maintaining high reliability of the graphene paper under multiple cycles of large deformation. Supercapacitor electrodes based on the crumpled graphene papers exhibit a unique combination of high stretchability (e.g., linear strain ~300%, areal strain ~800%), high electrochemical performance (e.g., specific capacitance ~196 F g-1), and high reliability (e.g., over 1000 stretch/relax cycles). An all-solid-state supercapacitor capable of large deformation is further fabricated to demonstrate practical applications of the crumpled-graphene-paper electrodes. Our method and design open a wide range of opportunities for manufacturing future energy-storage devices with desired deformability together with high performance.

  12. Stretchable and High-Performance Supercapacitors with Crumpled Graphene Papers

    Science.gov (United States)

    Zang, Jianfeng; Cao, Changyong; Feng, Yaying; Liu, Jie; Zhao, Xuanhe

    2014-01-01

    Fabrication of unconventional energy storage devices with high stretchability and performance is challenging, but critical to practical operations of fully power-independent stretchable electronics. While supercapacitors represent a promising candidate for unconventional energy-storage devices, existing stretchable supercapacitors are limited by their low stretchability, complicated fabrication process, and high cost. Here, we report a simple and low-cost method to fabricate extremely stretchable and high-performance electrodes for supercapacitors based on new crumpled-graphene papers. Electrolyte-mediated-graphene paper bonded on a compliant substrate can be crumpled into self-organized patterns by harnessing mechanical instabilities in the graphene paper. As the substrate is stretched, the crumpled patterns unfold, maintaining high reliability of the graphene paper under multiple cycles of large deformation. Supercapacitor electrodes based on the crumpled graphene papers exhibit a unique combination of high stretchability (e.g., linear strain ~300%, areal strain ~800%), high electrochemical performance (e.g., specific capacitance ~196 F g−1), and high reliability (e.g., over 1000 stretch/relax cycles). An all-solid-state supercapacitor capable of large deformation is further fabricated to demonstrate practical applications of the crumpled-graphene-paper electrodes. Our method and design open a wide range of opportunities for manufacturing future energy-storage devices with desired deformability together with high performance. PMID:25270673

  13. Transfer printing and patterning of stretchable electrospun film

    Energy Technology Data Exchange (ETDEWEB)

    Duan, Yongqing; Huang, YongAn, E-mail: yahuang@hust.edu.cn; Yin, Zhouping

    2013-10-01

    Electrospinning is an effective method for nanofiber production, but seldom used in the fabrication of patterned structures directly due to the whipping instability of the electrospinning jet. The whipping instability of electrospinning is adopted to fabricate stretchable patterned film by combination with an improved thermal transfer printing. The electrospun film is composed of small-scale wavy/coiled fibers, which make the patterned film highly stretchable. The optimal process parameters of whipping-based electrospinning are investigated to fabricate electrospun film with uniform and compact wavy/coiled fiber. Then the transfer printing and thermal detachment lithography are studied to generate patterned film, including the pressure, temperature, and peeling-off speed. Finally, the stretchability of the patterned electrospun film is studied through experiment and finite element analysis. It may open a cost-effective and high-throughput way for flexible/stretchable electronics fabrication. - Highlights: • Stretchable nonwoven film with small-scale wavy fibers is fabricated. • The film is transferred and patterned by thermal detachment lithography. • The patterned film is validated with high stretchability.

  14. An elastomeric grating coupler

    NARCIS (Netherlands)

    Kocabas, A.; Ay, F.; Dana, A.; Aydinli, A.

    We report on a novel nondestructive and reversible method for coupling free space light to planar optical waveguides. In this method, an elastomeric grating is used to produce an effective refractive index modulation on the surface of the optical waveguide. The external elastomeric grating binds to

  15. Bragg gratings in Topas

    DEFF Research Database (Denmark)

    Zhang, C.; Webb, D.J.; Kalli, K.

    We report for the first time fibre Bragg grating inscription in microstructured optical fibre fabricated from Topas® cyclic olefin copolymer. The temperature sensitivity of the grating was studied revealing a positive Bragg wavelength shift of approximately 0.8 nmK-1,the largest sensitivity yet...

  16. High-Performance Stretchable Conductive Composite Fibers from Surface-Modified Silver Nanowires and Thermoplastic Polyurethane by Wet Spinning.

    Science.gov (United States)

    Lu, Ying; Jiang, Jianwei; Yoon, Sungho; Kim, Kyung-Shik; Kim, Jae-Hyun; Park, Sanghyuk; Kim, Sang-Ho; Piao, Longhai

    2018-01-17

    Highly stretchable and conductive fibers have attracted great interest as a fundamental building block for the next generation of textile-based electronics. Because of its high conductivity and high aspect ratio, the Ag nanowire (AgNW) has been considered one of the most promising conducting materials for the percolation network-based conductive films and composites. However, the poor dispersibility of AgNWs in hydrophobic polymers has hindered their application to stretchable conductive composite fibers. In this paper, we present a highly stretchable and conductive composite fiber from the co-spinning of surface-modified AgNWs and thermoplastic polyurethane (PU). The surface modification of AgNWs with a polyethylene glycol derivative improved the compatibility of PU and AgNWs, which allowed the NWs to disperse homogeneously in the elastomeric matrix, forming effective percolation networks and causing the composite fiber to show enhanced electrical and mechanical performance. The maximum AgNW mass fraction in the composite fiber was 75.9 wt %, and its initial electrical conductivity was as high as 14 205 S/cm. The composite fibers also exhibited superior stretchability: the maximum rupture strain of the composite fiber with 14.6 wt % AgNW was 786%, and the composite fiber was also conductive even when it was stretched up to 200%. In addition, 2-dimensional (2-D) Ag nanoplates were added to the AgNW/PU composite fibers to increase the stability of the conductive network under repeated stretching and releasing. The Ag nanoplates acted as a bridge to effectively prevent the AgNWs from slippage and greatly improved the stability of the conductive network.

  17. Carbon Nanofiber versus Graphene-Based Stretchable Capacitive Touch Sensors for Artificial Electronic Skin.

    Science.gov (United States)

    Cataldi, Pietro; Dussoni, Simeone; Ceseracciu, Luca; Maggiali, Marco; Natale, Lorenzo; Metta, Giorgio; Athanassiou, Athanassia; Bayer, Ilker S

    2018-02-01

    Stretchable capacitive devices are instrumental for new-generation multifunctional haptic technologies particularly suited for soft robotics and electronic skin applications. A majority of elongating soft electronics still rely on silicone for building devices or sensors by multiple-step replication. In this study, fabrication of a reliable elongating parallel-plate capacitive touch sensor, using nitrile rubber gloves as templates, is demonstrated. Spray coating both sides of a rubber piece cut out of a glove with a conductive polymer suspension carrying dispersed carbon nanofibers (CnFs) or graphene nanoplatelets (GnPs) is sufficient for making electrodes with low sheet resistance values (≈10 Ω sq -1 ). The electrodes based on CnFs maintain their conductivity up to 100% elongation whereas the GnPs-based ones form cracks before 60% elongation. However, both electrodes are reliable under elongation levels associated with human joints motility (≈20%). Strikingly, structural damages due to repeated elongation/recovery cycles could be healed through annealing. Haptic sensing characteristics of a stretchable capacitive device by wrapping it around the fingertip of a robotic hand (ICub) are demonstrated. Tactile forces as low as 0.03 N and as high as 5 N can be easily sensed by the device under elongation or over curvilinear surfaces.

  18. Mechanical Properties of Organic Semiconductors for Stretchable, Highly Flexible, and Mechanically Robust Electronics.

    Science.gov (United States)

    Root, Samuel E; Savagatrup, Suchol; Printz, Adam D; Rodriquez, Daniel; Lipomi, Darren J

    2017-05-10

    Mechanical deformability underpins many of the advantages of organic semiconductors. The mechanical properties of these materials are, however, diverse, and the molecular characteristics that permit charge transport can render the materials stiff and brittle. This review is a comprehensive description of the molecular and morphological parameters that govern the mechanical properties of organic semiconductors. Particular attention is paid to ways in which mechanical deformability and electronic performance can coexist. The review begins with a discussion of flexible and stretchable devices of all types, and in particular the unique characteristics of organic semiconductors. It then discusses the mechanical properties most relevant to deformable devices. In particular, it describes how low modulus, good adhesion, and absolute extensibility prior to fracture enable robust performance, along with mechanical "imperceptibility" if worn on the skin. A description of techniques of metrology precedes a discussion of the mechanical properties of three classes of organic semiconductors: π-conjugated polymers, small molecules, and composites. The discussion of each class of materials focuses on molecular structure and how this structure (and postdeposition processing) influences the solid-state packing structure and thus the mechanical properties. The review concludes with applications of organic semiconductor devices in which every component is intrinsically stretchable or highly flexible.

  19. Defect grating modes as superimposed grating states

    NARCIS (Netherlands)

    van Groesen, Embrecht W.C.; Sopaheluwakan, A.; Andonowati, A.; de Ridder, R.M; de Ridder, R.M.; Altena, G; Altena, G.; Geuzebroek, D.H.; Geuzenboek, D.; Dekker, R.; Dekker, R

    2003-01-01

    For a symmetric grating structure with a defect, we show that a fully transmitted defect mode in the band gap can be obtained as a superposition of two steady states: an amplified and an attenuated defect state. Without scanning the whole band gap by transmission calculations, this simplifies the

  20. Spherical grating spectrometers

    Science.gov (United States)

    O'Donoghue, Darragh; Clemens, J. Christopher

    2014-07-01

    We describe designs for spectrometers employing convex dispersers. The Offner spectrometer was the first such instrument; it has almost exclusively been employed on satellite platforms, and has had little impact on ground-based instruments. We have learned how to fabricate curved Volume Phase Holographic (VPH) gratings and, in contrast to the planar gratings of traditional spectrometers, describe how such devices can be used in optical/infrared spectrometers designed specifically for curved diffraction gratings. Volume Phase Holographic gratings are highly efficient compared to conventional surface relief gratings; they have become the disperser of choice in optical / NIR spectrometers. The advantage of spectrometers with curved VPH dispersers is the very small number of optical elements used (the simplest comprising a grating and a spherical mirror), as well as illumination of mirrors off axis, resulting in greater efficiency and reduction in size. We describe a "Half Offner" spectrometer, an even simpler version of the Offner spectrometer. We present an entirely novel design, the Spherical Transmission Grating Spectrometer (STGS), and discuss exemplary applications, including a design for a double-beam spectrometer without any requirement for a dichroic. This paradigm change in spectrometer design offers an alternative to all-refractive astronomical spectrometer designs, using expensive, fragile lens elements fabricated from CaF2 or even more exotic materials. The unobscured mirror layout avoids a major drawback of the previous generation of catadioptric spectrometer designs. We describe laboratory measurements of the efficiency and image quality of a curved VPH grating in a STGS design, demonstrating, simultaneously, efficiency comparable to planar VPH gratings along with good image quality. The stage is now set for construction of a prototype instrument with impressive performance.

  1. Auxetic Mechanical Metamaterials to Enhance Sensitivity of Stretchable Strain Sensors.

    Science.gov (United States)

    Jiang, Ying; Liu, Zhiyuan; Matsuhisa, Naoji; Qi, Dianpeng; Leow, Wan Ru; Yang, Hui; Yu, Jiancan; Chen, Geng; Liu, Yaqing; Wan, Changjin; Liu, Zhuangjian; Chen, Xiaodong

    2018-03-01

    Stretchable strain sensors play a pivotal role in wearable devices, soft robotics, and Internet-of-Things, yet these viable applications, which require subtle strain detection under various strain, are often limited by low sensitivity. This inadequate sensitivity stems from the Poisson effect in conventional strain sensors, where stretched elastomer substrates expand in the longitudinal direction but compress transversely. In stretchable strain sensors, expansion separates the active materials and contributes to the sensitivity, while Poisson compression squeezes active materials together, and thus intrinsically limits the sensitivity. Alternatively, auxetic mechanical metamaterials undergo 2D expansion in both directions, due to their negative structural Poisson's ratio. Herein, it is demonstrated that such auxetic metamaterials can be incorporated into stretchable strain sensors to significantly enhance the sensitivity. Compared to conventional sensors, the sensitivity is greatly elevated with a 24-fold improvement. This sensitivity enhancement is due to the synergistic effect of reduced structural Poisson's ratio and strain concentration. Furthermore, microcracks are elongated as an underlying mechanism, verified by both experiments and numerical simulations. This strategy of employing auxetic metamaterials can be further applied to other stretchable strain sensors with different constituent materials. Moreover, it paves the way for utilizing mechanical metamaterials into a broader library of stretchable electronics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. Controlled buckling structures in semiconductor interconnects and nanomembranes for stretchable electronics

    Science.gov (United States)

    Rogers, John A; Meitl, Matthew; Sun, Yugang; Ko, Heung Cho; Carlson, Andrew; Choi, Won Mook; Stoykovich, Mark; Jiang, Hanqing; Huang, Yonggang; Nuzzo, Ralph G; Zhu, Zhengtao; Menard, Etienne; Khang, Dahl-Young

    2014-05-20

    In an aspect, the present invention provides stretchable, and optionally printable, components such as semiconductors and electronic circuits capable of providing good performance when stretched, compressed, flexed or otherwise deformed, and related methods of making or tuning such stretchable components. Stretchable semiconductors and electronic circuits preferred for some applications are flexible, in addition to being stretchable, and thus are capable of significant elongation, flexing, bending or other deformation along one or more axes. Further, stretchable semiconductors and electronic circuits of the present invention are adapted to a wide range of device configurations to provide fully flexible electronic and optoelectronic devices.

  3. A facile prestrain-stick-release assembly of stretchable supercapacitors based on highly stretchable and sticky hydrogel electrolyte

    Science.gov (United States)

    Tang, Qianqiu; Chen, Mingming; Wang, Gengchao; Bao, Hua; Saha, Petr

    2015-06-01

    A facile prestrain-stick-release assembly strategy for the stretchable supercapacitor device is developed based on a novel Na2SO4-aPUA/PAAM hydrogel electrolyte, saving the stretchable rubber base conventionally used. The Na2SO4-aPUA/PAAM hydrogel electrolyte exhibits high stretchability (>1000%), electrical conductivity (0.036 S cm-1) and stickiness. Due to the unique features of the hydrogel electrolyte, the carbon nanotube@MnO2 film electrodes can be firmly stuck to two sides of the prestrained hydrogel electrolyte. Then, by releasing the hydrogel electrolyte, homogenous buckles are formed for the film electrodes to get a full stretchable supercapacitor device. Besides, the high stickiness of the hydrogel electrolyte ensures its strong adhesion with the film electrodes, facilitating ion and electronic transfer of the supercapacitor. As a result, excellent electrochemical performance is achieved with the specific capacitance of 478.6 mF cm-2 at 0.5 mA cm-2 (corresponding to 201.1 F g-1) and capacitance retention of 91.5% after 3000 charging-discharging cycles under 150% strain, which is the best for the stretchable supercapacitors.

  4. Stretchable V2O5/PEDOT supercapacitors: a modular fabrication process and charging with triboelectric nanogenerators.

    Science.gov (United States)

    Qi, Ruijie; Nie, Jinhui; Liu, Mingyang; Xia, Mengyang; Lu, Xianmao

    2018-04-26

    Stretchable energy storage devices are of great importance for the viable applications of wearable/stretchable electronics. Studies on stretchable energy storage devices, especially supercapacitors (SCs), have shown encouraging progress. However, challenges still remain in the pursuit of high specific capacitances and facile fabrication methods. Herein, we report a modular materials fabrication and assembly process for stretchable SCs. With a V2O5/PEDOT composite as the active material, the resulting stretchable SCs exhibited high areal specific capacitances up to 240 mF cm-2 and good capacitance retention at a strain of 50%. To demonstrate the facile assembly process, a stretchable wristband was fabricated by simply assembling SC cells in series to deliver a voltage higher than 2 V. Charging the wristband with a triboelectric nanogenerator (TENG) to light an LED was further demonstrated, indicating the potential to integrate our SCs with environmental energy harvesters for self-powered stretchable devices.

  5. Miniaturized Stretchable and High-Rate Linear Supercapacitors.

    Science.gov (United States)

    Zhu, Wenjun; Zhang, Yang; Zhou, Xiaoshuang; Xu, Jiang; Liu, Zunfeng; Yuan, Ningyi; Ding, Jianning

    2017-12-01

    Linear stretchable supercapacitors have attracted much attention because they are well suited to applications in the rapidly expanding field of wearable electronics. However, poor conductivity of the electrode material, which limits the transfer of electrons in the axial direction of the linear supercapacitors, leads to a serious loss of capacity at high rates. To solve this problem, we use gold nanoparticles to decorate aligned multiwall carbon nanotube to fabricate stretchable linear electrodes. Furthermore, we have developed fine stretchable linear supercapacitors, which exhibited an extremely high elasticity up to 400% strain with a high capacitance of about 8.7 F g -1 at the discharge current of 1 A g -1 .

  6. Stretchable microelectrode array using room-temperature liquid alloy interconnects

    International Nuclear Information System (INIS)

    Wei, P; Ziaie, B; Taylor, R; Chung, C; Higgs, G; Pruitt, B L; Ding, Z; Abilez, O J

    2011-01-01

    In this paper, we present a stretchable microelectrode array for studying cell behavior under mechanical strain. The electrode array consists of gold-plated nail-head pins (250 µm tip diameter) or tungsten micro-wires (25.4 µm in diameter) inserted into a polydimethylsiloxane (PDMS) platform (25.4 × 25.4 mm 2 ). Stretchable interconnects to the outside were provided by fusible indium-alloy-filled microchannels. The alloy is liquid at room temperature, thus providing the necessary stretchability and electrical conductivity. The electrode platform can withstand strains of up to 40% and repeated (100 times) strains of up to 35% did not cause any failure in the electrodes or the PDMS substrate. We confirmed biocompatibility of short-term culture, and using the gold pin device, we demonstrated electric field pacing of adult murine heart cells. Further, using the tungsten microelectrode device, we successfully measured depolarizations of differentiated murine heart cells from embryoid body clusters

  7. Graphene-based flexible and stretchable thin film transistors.

    Science.gov (United States)

    Yan, Chao; Cho, Jeong Ho; Ahn, Jong-Hyun

    2012-08-21

    Graphene has been attracting wide attention owing to its superb electronic, thermal and mechanical properties. These properties allow great applications in the next generation of optoelectronics, where flexibility and stretchability are essential. In this context, the recent development of graphene growth/transfer and its applications in field-effect transistors are involved. In particular, we provide a detailed review on the state-of-the-art of graphene-based flexible and stretchable thin film transistors. We address the principles of fabricating high-speed graphene analog transistors and the key issues of producing an array of graphene-based transistors on flexible and stretchable substrates. It provides a platform for future work to focus on understanding and realizing high-performance graphene-based transistors.

  8. Mechanical Designs for Inorganic Stretchable Circuits in Soft Electronics.

    Science.gov (United States)

    Wang, Shuodao; Huang, Yonggang; Rogers, John A

    2015-09-01

    Mechanical concepts and designs in inorganic circuits for different levels of stretchability are reviewed in this paper, through discussions of the underlying mechanics and material theories, fabrication procedures for the constituent microscale/nanoscale devices, and experimental characterization. All of the designs reported here adopt heterogeneous structures of rigid and brittle inorganic materials on soft and elastic elastomeric substrates, with mechanical design layouts that isolate large deformations to the elastomer, thereby avoiding potentially destructive plastic strains in the brittle materials. The overall stiffnesses of the electronics, their stretchability, and curvilinear shapes can be designed to match the mechanical properties of biological tissues. The result is a class of soft stretchable electronic systems that are compatible with traditional high-performance inorganic semiconductor technologies. These systems afford promising options for applications in portable biomedical and health-monitoring devices. Mechanics theories and modeling play a key role in understanding the underlining physics and optimization of these systems.

  9. Stretchable, Porous, and Conductive Energy Textiles

    KAUST Repository

    Hu, Liangbing; Pasta, Mauro; Mantia, Fabio La; Cui, LiFeng; Jeong, Sangmoo; Deshazer, Heather Dawn; Choi, Jang Wook; Han, Seung Min; Cui, Yi

    2010-01-01

    Recently there is strong interest in lightweight, flexible, and wearable electronics to meet the technological demands of modern society. Integrated energy storage devices of this type are a key area that is still significantly underdeveloped. Here, we describe wearable power devices using everyday textiles as the platform. With an extremely simple "dipping and drying" process using single-walled carbon nanotube (SWNT) ink, we produced highly conductive textiles with conductivity of 125 S cm-1 and sheet resistance less than 1 Ω/sq. Such conductive textiles show outstanding flexibility and stretchability and demonstrate strong adhesion between the SWNTs and the textiles of interest. Supercapacitors made from these conductive textiles show high areal capacitance, up to 0.48F/cm2, and high specific energy. We demonstrate the loading of pseudocapacitor materials into these conductive textiles that leads to a 24-fold increase of the areal capacitance of the device. These highly conductive textiles can provide new design opportunities for wearable electronics and energy storage applications. © 2010 American Chemical Society.

  10. Stretchable, Porous, and Conductive Energy Textiles

    KAUST Repository

    Hu, Liangbing

    2010-02-10

    Recently there is strong interest in lightweight, flexible, and wearable electronics to meet the technological demands of modern society. Integrated energy storage devices of this type are a key area that is still significantly underdeveloped. Here, we describe wearable power devices using everyday textiles as the platform. With an extremely simple "dipping and drying" process using single-walled carbon nanotube (SWNT) ink, we produced highly conductive textiles with conductivity of 125 S cm-1 and sheet resistance less than 1 Ω/sq. Such conductive textiles show outstanding flexibility and stretchability and demonstrate strong adhesion between the SWNTs and the textiles of interest. Supercapacitors made from these conductive textiles show high areal capacitance, up to 0.48F/cm2, and high specific energy. We demonstrate the loading of pseudocapacitor materials into these conductive textiles that leads to a 24-fold increase of the areal capacitance of the device. These highly conductive textiles can provide new design opportunities for wearable electronics and energy storage applications. © 2010 American Chemical Society.

  11. Free form CMOS electronics: Physically flexible and stretchable

    KAUST Repository

    Hussain, Muhammad Mustafa

    2015-12-07

    Free form (physically flexible and stretchable) electronics can be used for applications which are unexplored today due to the rigid and brittle nature of the state-of-the-art electronics. Therefore, we show integration strategy to rationally design materials, processes and devices to transform advanced complementary metal oxide semiconductor (CMOS) electronics into flexible and stretchable one while retaining their high performance, energy efficiency, ultra-large-scale-integration (ULSI) density, reliability and performance over cost benefit to expand its applications for wearable, implantable and Internet-of-Everything electronics.

  12. Kirigami-based stretchable lithium-ion batteries

    Science.gov (United States)

    Song, Zeming; Wang, Xu; Lv, Cheng; An, Yonghao; Liang, Mengbing; Ma, Teng; He, David; Zheng, Ying-Jie; Huang, Shi-Qing; Yu, Hongyu; Jiang, Hanqing

    2015-01-01

    We have produced stretchable lithium-ion batteries (LIBs) using the concept of kirigami, i.e., a combination of folding and cutting. The designated kirigami patterns have been discovered and implemented to achieve great stretchability (over 150%) to LIBs that are produced by standardized battery manufacturing. It is shown that fracture due to cutting and folding is suppressed by plastic rolling, which provides kirigami LIBs excellent electrochemical and mechanical characteristics. The kirigami LIBs have demonstrated the capability to be integrated and power a smart watch, which may disruptively impact the field of wearable electronics by offering extra physical and functionality design spaces. PMID:26066809

  13. 3D Printing of Highly Stretchable, Shape-Memory, and Self-Healing Elastomer toward Novel 4D Printing.

    Science.gov (United States)

    Kuang, Xiao; Chen, Kaijuan; Dunn, Conner K; Wu, Jiangtao; Li, Vincent C F; Qi, H Jerry

    2018-02-28

    The three-dimensional (3D) printing of flexible and stretchable materials with smart functions such as shape memory (SM) and self-healing (SH) is highly desirable for the development of future 4D printing technology for myriad applications, such as soft actuators, deployable smart medical devices, and flexible electronics. Here, we report a novel ink that can be used for the 3D printing of highly stretchable, SM, and SH elastomer via UV-light-assisted direct-ink-write printing. An ink containing urethane diacrylate and a linear semicrystalline polymer is developed for the 3D printing of a semi-interpenetrating polymer network elastomer that can be stretched by up to 600%. The 3D-printed complex structures show interesting functional properties, such as high strain SM and SM -assisted SH capability. We demonstrate that such a 3D-printed SM elastomer has the potential application for biomedical devices, such as vascular repair devices. This research paves a new way for the further development of novel 4D printing, soft robotics, and biomedical devices.

  14. Holographic diffraction gratings as laser radiation protection filters

    International Nuclear Information System (INIS)

    Pantelic, D.; Pantelic, G.

    2006-01-01

    Holographic volume diffraction gratings are used as attenuation filters, due to their selective spectral transmission. They can be tailored to reflect or transmit narrow spectral ranges by adjusting spatial frequency of Bragg grating in carefully chosen photosensitive materials, like silver-halide emulsion or di-chromated gelatin layers. If properly recorded and chemically processed, resulting gratings can significantly attenuate light at wavelengths corresponding to various laser spectral lines. Thus, they can be used as filters in laser protection goggles. We analyze the characteristics of Bragg gratings necessary to obtain high attenuation coefficients. Also, their angular selectivity is taken into account and corresponding experimental conditions are investigated. Although di-chromated gelatin seems to be almost ideal material, due to its almost 100% diffraction efficiency, environmental stability is poor (degradation under humid environment), thus making its practical usage difficult. Thus, we have analyzed alternative materials like di-chromated pullulan, which is stable under normal environmental conditions (without drop in diffraction efficiency after prolonged exposure to humidity). Pullulan is polymer (polysaccharide) of biologic origin produced by certain bacteria. If doped with chromium ions it becomes photosensitive, enabling recording of diffraction gratings with spatial frequency of more than 3000 lines/mm. Material is chemically processed by mixture of isopropyl alcohol and water. Both thick and thin layers can be produced by gravity settling. Spectral properties of resulting gratings are analyzed, showing that they can significantly attenuate laser light of particular wavelength, depending of grating period and its slant angle. (authors)

  15. 3-D printing of liquid metals for stretchable and flexible conductors

    Science.gov (United States)

    Trlica, Chris; Parekh, Dishit Paresh; Panich, Lazar; Ladd, Collin; Dickey, Michael D.

    2014-06-01

    3-D printing is an emerging technology that has been used primarily on small scales for rapid prototyping, but which could also herald a wider movement towards decentralized, highly customizable manufacturing. Polymers are the most common materials to be 3-D printed today, but there is great demand for a way to easily print metals. Existing techniques for 3-D printing metals tend to be expensive and energy-intensive, and usually require high temperatures or pressures, making them incompatible with polymers, organics, soft materials, and biological materials. Here, we describe room temperature liquid metals as complements to polymers for 3-D printing applications. These metals enable the fabrication of soft, flexible, and stretchable devices. We survey potential room temperature liquid metal candidates and describe the benefits of gallium and its alloys for these purposes. We demonstrate the direct printing of a liquid gallium alloy in both 2-D and 3-D and highlight the structures and shapes that can be fabricated using these processes.

  16. Switchable Bragg gratings

    DEFF Research Database (Denmark)

    Marckmann, Carl Johan

    2003-01-01

    Research Center (MIC) at the Technical University of Denmark. The Bragg gratings were fabricated at COM using UV irradiation of the planar waveguides using the phase mask method. The induction of a frozen-in DC electric field into the samples was performed by thermal poling of the Bragg gratings...... layers, it becam possible to investigate the symmetry properties of the third-order nonlinearities. Contrary to the expectations for an amorphous material, the measurements indicated an almost polarization independent third-order nonlinearity - the most probable explanation being electrostriction......The subject of this ph.d. thesis was the development of an electrically switchable Bragg grating made in an optical waveguide using thermal poling to be applied within optical telecommunication systems. The planar waveguides used in this thesis were fabricated at the Micro- and Nanotechnology...

  17. Nanoimprinted reflecting gratings for long-range surface plasmon polaritons

    DEFF Research Database (Denmark)

    Pedersen, Rasmus Haugstrup; Boltasseva, Alexandra; Johansen, Dan Mario

    2007-01-01

    We present a novel design, fabrication, and characterization of reflecting gratings for long-range surface plasmon polaritons (LR-SPPs) at telecom wavelengths. LR-SPP waveguides consisting of a thin (12 nm) gold film embedded in a thick (45 μm) layer of dielectric polymer cladding are structured...

  18. POF based glucose sensor incorporating grating wavelength filters

    DEFF Research Database (Denmark)

    Hassan, Hafeez Ul; Aasmul, Søren; Bang, Ole

    2014-01-01

    AND RESEARCH IN POLYMER OPTICAL DEVICES; TRIPOD. Within the domain of TRIPOD, research is conducted on "Plastic Optical Fiber based Glucose Sensors Incorporating Grating Wavelength Filters". Research will be focused to optimized fiber tips for better coupling efficiency, reducing the response time of sensor...

  19. Grateful Med: getting started.

    Science.gov (United States)

    Shearer, B; McCann, L; Crump, W J

    1990-01-01

    When a local medical library is not available, it is often necessary for physicians to discover alternate ways to receive medical information. Rural physicians, particularly, can make use of a computer program called Grateful Med that provides access to the same literature available to physicians in large cities. This program permits the user to perform database searches on the National Library of Medicine database (MEDLINE), corresponding to the primary index to medical literature, Index Medicus. In this article, we give the procedure for procuring a National Library of Medicine password and for making efficient use of the Grateful Med program.

  20. High-performance, stretchable, wire-shaped supercapacitors.

    Science.gov (United States)

    Chen, Tao; Hao, Rui; Peng, Huisheng; Dai, Liming

    2015-01-07

    A general approach toward extremely stretchable and highly conductive electrodes was developed. The method involves wrapping a continuous carbon nanotube (CNT) thin film around pre-stretched elastic wires, from which high-performance, stretchable wire-shaped supercapacitors were fabricated. The supercapacitors were made by twisting two such CNT-wrapped elastic wires, pre-coated with poly(vinyl alcohol)/H3PO4 hydrogel, as the electrolyte and separator. The resultant wire-shaped supercapacitors exhibited an extremely high elasticity of up to 350% strain with a high device capacitance up to 30.7 F g(-1), which is two times that of the state-of-the-art stretchable supercapacitor under only 100% strain. The wire-shaped structure facilitated the integration of multiple supercapacitors into a single wire device to meet specific energy and power needs for various potential applications. These supercapacitors can be repeatedly stretched from 0 to 200% strain for hundreds of cycles with no change in performance, thus outperforming all the reported state-of-the-art stretchable electronics. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. Graphene-based stretchable and transparent moisture barrier

    Science.gov (United States)

    Won, Sejeong; Van Lam, Do; Lee, Jin Young; Jung, Hyun-June; Hur, Min; Kim, Kwang-Seop; Lee, Hak-Joo; Kim, Jae-Hyun

    2018-03-01

    We propose an alumina-deposited double-layer graphene (2LG) as a transparent, scalable, and stretchable barrier against moisture; this barrier is indispensable for foldable or stretchable organic displays and electronics. Both the barrier property and stretchability were significantly enhanced through the introduction of 2LG between alumina and a polymeric substrate. 2LG with negligible polymeric residues was coated on the polymeric substrate via a scalable dry transfer method in a roll-to-roll manner; an alumina layer was deposited on the graphene via atomic layer deposition. The effect of the graphene layer on crack generation in the alumina layer was systematically studied under external strain using an in situ micro-tensile tester, and correlations between the deformation-induced defects and water vapor transmission rate were quantitatively analyzed. The enhanced stretchability of alumina-deposited 2LG originated from the interlayer sliding between the graphene layers, which resulted in the crack density of the alumina layer being reduced under external strain.

  2. A Platform for Manufacturable Stretchable Micro-electrode Arrays

    NARCIS (Netherlands)

    Khoshfetrat Pakazad, S.; Savov, A.; Braam, S.R.; Dekker, R.

    2012-01-01

    A platform for the batch fabrication of pneumatically actuated Stretchable Micro-Electrode Arrays (SMEAs) by using state-of-the-art micro-fabrication techniques and materials is demonstrated. The proposed fabrication process avoids the problems normally associated with processing of thin film

  3. Stretchable transistors with buckled carbon nanotube films as conducting channels

    Science.gov (United States)

    Arnold, Michael S; Xu, Feng

    2015-03-24

    Thin-film transistors comprising buckled films comprising carbon nanotubes as the conductive channel are provided. Also provided are methods of fabricating the transistors. The transistors, which are highly stretchable and bendable, exhibit stable performance even when operated under high tensile strains.

  4. Birefringence Bragg Binary (3B) grating, quasi-Bragg grating and immersion gratings

    Science.gov (United States)

    Ebizuka, Noboru; Morita, Shin-ya; Yamagata, Yutaka; Sasaki, Minoru; Bianco, Andorea; Tanabe, Ayano; Hashimoto, Nobuyuki; Hirahara, Yasuhiro; Aoki, Wako

    2014-07-01

    A volume phase holographic (VPH) grating achieves high angular dispersion and very high diffraction efficiency for the first diffraction order and for S or P polarization. However the VPH grating could not achieve high diffraction efficiency for non-polarized light at a large diffraction angle because properties of diffraction efficiencies for S and P polarizations are different. Furthermore diffraction efficiency of the VPH grating extinguishes toward a higher diffraction order. A birefringence binary Bragg (3B) grating is a thick transmission grating with optically anisotropic material such as lithium niobate or liquid crystal. The 3B grating achieves diffraction efficiency up to 100% for non-polarized light by tuning of refractive indices for S and P polarizations, even in higher diffraction orders. We fabricated 3B grating with liquid crystal and evaluated the performance of the liquid crystal grating. A quasi-Bragg (QB) grating, which consists long rectangle mirrors aligned in parallel precisely such as a window shade, also achieves high diffraction efficiency toward higher orders. We fabricated QB grating by laminating of silica glass substrates and glued by pressure fusion of gold films. A quasi-Bragg immersion (QBI) grating has smooth mirror hypotenuse and reflector array inside the hypotenuse, instead of step-like grooves of a conventional immersion grating. An incident beam of the QBI grating reflects obliquely at a reflector, then reflects vertically at the mirror surface and reflects again at the same reflector. We are going to fabricate QBI gratings by laminating of mirror plates as similar to fabrication of the QB grating. We will also fabricate silicon and germanium immersion gratings with conventional step-like grooves by means of the latest diamond machining methods. We introduce characteristics and performance of these gratings.

  5. Electro-optic diffraction grating tuned laser

    International Nuclear Information System (INIS)

    Hughes, R.S.

    1975-01-01

    An electro-optic diffraction grating tuned laser comprising a laser medium, output mirror, retro-reflective grating and an electro-optic diffraction grating beam deflector positioned between the laser medium and the reflective diffraction grating is described. An optional angle multiplier may be used between the electro-optic diffraction grating and the reflective grating. (auth)

  6. Bragg grating rogue wave

    Energy Technology Data Exchange (ETDEWEB)

    Degasperis, Antonio [Dipartimento di Fisica, “Sapienza” Università di Roma, P.le A. Moro 2, 00185 Roma (Italy); Wabnitz, Stefan, E-mail: stefan.wabnitz@unibs.it [Dipartimento di Ingegneria dell' Informazione, Università degli Studi di Brescia and INO-CNR, via Branze 38, 25123 Brescia (Italy); Aceves, Alejandro B. [Southern Methodist University, Dallas (United States)

    2015-06-12

    We derive the rogue wave solution of the classical massive Thirring model, that describes nonlinear optical pulse propagation in Bragg gratings. Combining electromagnetically induced transparency with Bragg scattering four-wave mixing may lead to extreme waves at extremely low powers.

  7. Silicon graphene Bragg gratings.

    Science.gov (United States)

    Capmany, José; Domenech, David; Muñoz, Pascual

    2014-03-10

    We propose the use of interleaved graphene sections on top of a silicon waveguide to implement tunable Bragg gratings. The filter central wavelength and bandwidth can be controlled changing the chemical potential of the graphene sections. Apodization techniques are also presented.

  8. Fast and stable gratings inscription in POFs made of different materials with pulsed 248 nm KrF laser

    DEFF Research Database (Denmark)

    Marques, C. A.F.; Min, R.; Leal, A.

    2018-01-01

    This paper presents fiber Bragg grating (FBG) inscription with a pulsed 248 nm UV KrF laser in polymer optical fibers (POFs) made of different polymers, namely polymethyl methacrylate (PMMA), cyclic-olefin polymer and co-polymer, and Polycarbonate. The inscribed gratings and the corresponding...... inscription parameters are compared with grating inscribed in POFs made of the aforementioned materials but with the hitherto most used laser for inscription, which is a continuous wave 325 nm UV HeCd laser. Results show a reduction of the inscription time of at least 16 times. The maximum time reduction...... is more than 130 times. In addition, a reflectivity and a bandwidth close to or higher than the ones with the 325 nm laser were obtained. The polymer optical fiber Bragg gratings (POFBGs) inscribed with the 248 nm laser setup present high stability with small variations in their central wavelength...

  9. Spirally Structured Conductive Composites for Highly Stretchable, Robust Conductors and Sensors.

    Science.gov (United States)

    Wu, Xiaodong; Han, Yangyang; Zhang, Xinxing; Lu, Canhui

    2017-07-12

    Flexible and stretchable electronics are highly desirable for next generation devices. However, stretchability and conductivity are fundamentally difficult to combine for conventional conductive composites, which restricts their widespread applications especially as stretchable electronics. Here, we innovatively develop a new class of highly stretchable and robust conductive composites via a simple and scalable structural approach. Briefly, carbon nanotubes are spray-coated onto a self-adhesive rubber film, followed by rolling up the film completely to create a spirally layered structure within the composites. This unique spirally layered structure breaks the typical trade-off between stretchability and conductivity of traditional conductive composites and, more importantly, restrains the generation and propagation of mechanical microcracks in the conductive layer under strain. Benefiting from such structure-induced advantages, the spirally layered composites exhibit high stretchability and flexibility, good conductive stability, and excellent robustness, enabling the composites to serve as highly stretchable conductors (up to 300% strain), versatile sensors for monitoring both subtle and large human activities, and functional threads for wearable electronics. This novel and efficient methodology provides a new design philosophy for manufacturing not only stretchable conductors and sensors but also other stretchable electronics, such as transistors, generators, artificial muscles, etc.

  10. Holographic grating relaxation technique for soft matter science

    Energy Technology Data Exchange (ETDEWEB)

    Lesnichii, Vasilii, E-mail: vasilii.lesnichii@physchem.uni-freiburg.de [Institute of Physical Chemistry, Albertstraße 21, Institute of Macromolecular Chemistry, Stefan-Meier-Str. 31, Albert-Ludwigs Universität, Freiburg im Breisgau 79104 (Germany); ITMO University, Kronverksky prospekt 49, Saint-Petersburg 197101 (Russian Federation); Kiessling, Andy [Institute of Physical Chemistry, Albertstraße 21, Institute of Macromolecular Chemistry, Stefan-Meier-Str. 31, Albert-Ludwigs Universität, Freiburg im Breisgau 79104 (Germany); Current address: Illinois Institute of Technology, 10 West 33rd Street, Chicago,IL60616 (United States); Bartsch, Eckhard [Institute of Physical Chemistry, Albertstraße 21, Institute of Macromolecular Chemistry, Stefan-Meier-Str. 31, Albert-Ludwigs Universität, Freiburg im Breisgau 79104 (Germany); Veniaminov, Andrey, E-mail: veniaminov@phoi.ifmo.ru [ITMO University, Kronverksky prospekt 49, Saint-Petersburg 197101 (Russian Federation)

    2016-06-17

    The holographic grating relaxation technique also known as forced Rayleigh scattering consists basically in writing a holographic grating in the specimen of interest and monitoring its diffraction efficiency as a function of time, from which valuable information on mass or heat transfer and photoinduced transformations can be extracted. In a more detailed view, the shape of the relaxation curve and the relaxation rate as a function of the grating period were found to be affected by the architecture of diffusing species (molecular probes) that constitute the grating, as well as that of the environment they diffuse in, thus making it possible to access and study spatial heterogeneity of materials and different modes of e.g., polymer motion. Minimum displacements and spatial domains approachable by the technique are in nanometer range, well below spatial periods of holographic gratings. In the present paper, several cases of holographic relaxation in heterogeneous media and complex motions are exemplified. Nano- to micro-structures or inhomogeneities comparable in spatial scale with holographic gratings manifest themselves in relaxation experiments via non-exponential decay (stepwise or stretched), spatial-period-dependent apparent diffusion coefficient, or unusual dependence of diffusion coefficient on molecular volume of diffusing probes.

  11. Comparison of compression properties of stretchable knitted fabrics and bi-stretch woven fabrics for compression garments

    NARCIS (Netherlands)

    Maqsood, Muhammad

    2017-01-01

    Stretchable fabrics have diverse applications ranging from casual apparel to performance sportswear and compression therapy. Compression therapy is the universally accepted treatment for the management of hypertrophic scarring after severe burns. Mostly stretchable knitted fabrics are used in

  12. Optical fiber Bragg gratings. Part II. Modeling of finite-length gratings and grating arrays.

    Science.gov (United States)

    Passaro, Vittorio M N; Diana, Roberto; Armenise, Mario N

    2002-09-01

    A model of both uniform finite-length optical fiber Bragg gratings and grating arrays is presented. The model is based on the Floquet-Bloch formalism and allows rigorous investigation of all the physical aspects in either single- or multiple-periodic structures realized on the core of a monomodal fiber. Analytical expressions of reflectivity and transmittivity for both single gratings and grating arrays are derived. The influence of the grating length and the index modulation amplitude on the reflected and transmitted optical power for both sinusoidal and rectangular profiles is evaluated. Good agreement between our method and the well-known coupled-mode theory (CMT) approach has been observed for both single gratings and grating arrays only in the case of weak index perturbation. Significant discrepancies exist there in cases of strong index contrast because of the increasing approximation of the CMT approach. The effects of intragrating phase shift are also shown and discussed.

  13. Grating stimulated echo

    International Nuclear Information System (INIS)

    Dubetsky, B.; Berman, P.R.; Sleator, T.

    1992-01-01

    A theory of a grating simulated echo (GTE) is developed. The GSE involves the sequential excitation of atoms by two counterpropagating traveling waves, a standing wave, and a third traveling wave. It is shown that the echo signal is very sensitive to small changes in atomic velocity, much more sensitive than the normal stimulated echo. Use of the GSE as a collisional probe or accelerometer is discussed

  14. Flexible and Stretchable Optoelectronic Devices using Silver Nanowires and Graphene.

    Science.gov (United States)

    Lee, Hanleem; Kim, Meeree; Kim, Ikjoon; Lee, Hyoyoung

    2016-06-01

    Many studies have accompanied the emergence of a great interest in flexible or/and stretchable devices for new applications in wearable and futuristic technology, including human-interface devices, robotic skin, and biometric devices, and in optoelectronic devices. Especially, new nanodimensional materials enable flexibility or stretchability to be brought based on their dimensionality. Here, the emerging field of flexible devices is briefly introduced using silver nanowires and graphene, which are famous nanomaterials for the use of transparent conductive electrodes, as examples, and their unique functions originating from the intrinsic property of these nanomaterials are highlighted. It is thought that this work will evoke more interest and idea exchanges in this emerging field and hopefully can trigger a breakthrough on a new type of optoelectronics and optogenetic devices in the near future. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Stretchable Conductive Composites from Cu-Ag Nanowire Felt.

    Science.gov (United States)

    Catenacci, Matthew J; Reyes, Christopher; Cruz, Mutya A; Wiley, Benjamin J

    2018-04-24

    Materials that retain a high conductivity under strain are essential for wearable electronics. This article describes a conductive, stretchable composite consisting of a Cu-Ag core-shell nanowire felt infiltrated with a silicone elastomer. This composite exhibits a retention of conductivity under strain that is superior to any composite with a conductivity greater than 1000 S cm -1 . This work also shows how the mechanical properties, conductivity, and deformation mechanism of the composite changes as a function of the stiffness of the silicone matrix. The retention of conductivity under strain was found to decrease as the Young's modulus of the matrix increased. This was attributed to void formation as a result of debonding between the nanowire felt and the elastomer. The nanowire composite was also patterned to create serpentine circuits with a stretchability of 300%.

  16. Electrochemically synthesized stretchable polypyrrole/fabric electrodes for supercapacitor

    International Nuclear Information System (INIS)

    Yue, Binbin; Wang, Caiyun; Ding, Xin; Wallace, Gordon G.

    2013-01-01

    Wearable electronics offer the combined advantages of both electronics and fabrics. Being an indispensable part of these electronics, lightweight, stretchable and wearable power sources are strongly demanded. Here we describe a daily-used cotton fabric coated with polypyrrole as electrode for stretchable supercapacitors. Polypyrrole was synthesized on the Au coated fabric via an electrochemical polymerization process with p-toluenesulfonic acid (p-TS) as dopant from acetonitrile solution. This material was characterized with FESEM, tensile stress, and studied as a supercapacitor electrode in 1.0 M NaCl. This conductive textile electrode can sustain up to 140% strain without electric failure. It delivers a high specific capacitance of 254.9 F g −1 at a scan rate of 10 mV s −1 , and keeps almost unchanged at an applied strain (i.e. 30% and 50%) but with an improved cycling stability

  17. Mechanical response of spiral interconnect arrays for highly stretchable electronics

    KAUST Repository

    Qaiser, Nadeem

    2017-11-21

    A spiral interconnect array is a commonly used architecture for stretchable electronics, which accommodates large deformations during stretching. Here, we show the effect of different geometrical morphologies on the deformation behavior of the spiral island network. We use numerical modeling to calculate the stresses and strains in the spiral interconnects under the prescribed displacement of 1000 μm. Our result shows that spiral arm elongation depends on the angular position of that particular spiral in the array. We also introduce the concept of a unit-cell, which fairly replicates the deformation mechanism for full complex hexagon, diamond, and square shaped arrays. The spiral interconnects which are axially connected between displaced and fixed islands attain higher stretchability and thus experience the maximum deformations. We perform tensile testing of 3D printed replica and find that experimental observations corroborate with theoretical study.

  18. Stretchable Metamaterial Absorber Using Liquid Metal-Filled Polydimethylsiloxane (PDMS

    Directory of Open Access Journals (Sweden)

    Kyeongseob Kim

    2016-04-01

    Full Text Available A stretchable metamaterial absorber is proposed in this study. The stretchability was achieved by liquid metal and polydimethylsiloxane (PDMS. To inject liquid metal, microfluidic channels were fabricated using PDMS powers and microfluidic-channel frames, which were built using a three-dimensional printer. A top conductive pattern and ground plane were designed after considering the easy injection of liquid metal. The proposed metamaterial absorber comprises three layers of PDMS substrate. The top layer is for the top conductive pattern, and the bottom layer is for the meandered ground plane. Flat PDMS layers were inserted between the top and bottom PDMS layers. The measured absorptivity of the fabricated absorber was 97.8% at 18.5 GHz, and the absorption frequency increased from 18.5 to 18.65 GHz as the absorber was stretched from its original length (5.2 cm to 6.4 cm.

  19. Ultrasensitive, Stretchable Strain Sensors Based on Fragmented Carbon Nanotube Papers

    KAUST Repository

    Zhou, Jian

    2017-01-17

    The development of strain sensors featuring both ultra high sensitivity and high stretchability is still a challenge. We demonstrate that strain sensors based on fragmented single-walled carbon nanotube (SWCNT) paper embedded in poly(dimethylsiloxane) (PDMS) can sustain their sensitivity even at very high strain levels (with a gauge factor of over 10(7) at 50% strain). This record sensitivity is ascribed to the low initial electrical resistance (5-28 Omega) of the SWCNT paper and the wide change in resistance (up to 10(6) Omega) governed by the percolated network of SWCNT in the cracked region. The sensor response remains nearly unchanged after 10 000 strain cycles at 20% proving the robustness of this technology. This fragmentation based sensing system brings opportunities to engineer highly sensitive stretchable sensors.

  20. Mechanical response of spiral interconnect arrays for highly stretchable electronics

    KAUST Repository

    Qaiser, Nadeem; Khan, S. M.; Nour, Maha A.; Rehman, M. U.; Rojas, J. P.; Hussain, Muhammad Mustafa

    2017-01-01

    A spiral interconnect array is a commonly used architecture for stretchable electronics, which accommodates large deformations during stretching. Here, we show the effect of different geometrical morphologies on the deformation behavior of the spiral island network. We use numerical modeling to calculate the stresses and strains in the spiral interconnects under the prescribed displacement of 1000 μm. Our result shows that spiral arm elongation depends on the angular position of that particular spiral in the array. We also introduce the concept of a unit-cell, which fairly replicates the deformation mechanism for full complex hexagon, diamond, and square shaped arrays. The spiral interconnects which are axially connected between displaced and fixed islands attain higher stretchability and thus experience the maximum deformations. We perform tensile testing of 3D printed replica and find that experimental observations corroborate with theoretical study.

  1. Recent Advances in Flexible/Stretchable Supercapacitors for Wearable Electronics.

    Science.gov (United States)

    Li, La; Lou, Zheng; Chen, Di; Jiang, Kai; Han, Wei; Shen, Guozhen

    2017-11-22

    The popularization of personalized wearable devices has accelerated the development of flexible/stretchable supercapacitors (SCs) that possess remarkable features of miniaturization, high security, and easy integration to build an all-in-one integrated system, and realize the functions of comfortable, noninvasive and continuous health monitoring, motion records, and information acquisition, etc. This Review presents a brief phylogeny of flexible/stretchable SCs, represented by planar micro-supercapacitors (MSCs) and 1D fibrous SCs. The latest progress and advantages of different flexible/stretchable/self-healing substrate, solid-state electrolyte and electrode materials for the fabrication of wearable SCs devices are summarized. The various configurations used in planar MSCs and 1D fibrous SCs aiming at the improvement of performance are also discussed. In addition, from the viewpoint of practical value and large-scale production, a survey of integrated systems, from different types of SC powered wearable sensing (gas, pressure, tactile…) systems, wearable all-in-one systems (including energy harvest, storage, and functional groups), to device packaging is presented. Finally, the challenges and future perspectives of wearable SCs are also considered. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  2. A Stretchable Electromagnetic Absorber Fabricated Using Screen Printing Technology.

    Science.gov (United States)

    Jeong, Heijun; Lim, Sungjoon

    2017-05-21

    A stretchable electromagnetic absorber fabricated using screen printing technology is proposed in this paper. We used a polydimethylsiloxane (PDMS) substrate to fabricate the stretchable absorber since PDMS exhibits good dielectric properties, flexibility, and restoring capabilities. DuPont PE872 (DuPont, Wilmington, CT, USA), a stretchable silver conductive ink, was used for the screen printing technique. The reflection coefficient of the absorber was measured using a vector network analyzer and a waveguide. The proposed absorber was designed as a rectangular patch unit cell, wherein the top of the unit cell acted as the patch and the bottom formed the ground. The size of the patch was 8 mm × 7 mm. The prototype of the absorber consisted of two unit cells such that it fits into the WR-90 waveguide (dimensions: 22.86 mm × 10.16 mm) for experimental measurement. Before stretching the absorber, the resonant frequency was 11 GHz. When stretched along the x -direction, the resonant frequency shifted by 0.1 GHz, from 11 to 10.9 GHz, demonstrating 99% absorption. Furthermore, when stretched along the y -direction, the resonant frequency shifted by 0.6 GHz, from 11 to 10.4 GHz, demonstrating 99% absorption.

  3. Electrohydrodynamic printing of silver nanowires for flexible and stretchable electronics.

    Science.gov (United States)

    Cui, Zheng; Han, Yiwei; Huang, Qijin; Dong, Jingyan; Zhu, Yong

    2018-04-19

    A silver nanowire (AgNW) based conductor is a promising component for flexible and stretchable electronics. A wide range of flexible/stretchable devices using AgNW conductors has been demonstrated recently. High-resolution, high-throughput printing of AgNWs remains a critical challenge. Electrohydrodynamic (EHD) printing has been developed as a promising technique to print different materials on a variety of substrates with high resolution. Here, AgNW ink was developed for EHD printing. The printed features can be controlled by several parameters including AgNW concentration, ink viscosity, printing speed, stand-off distance, etc. With this method, AgNW patterns can be printed on a range of substrates, e.g. paper, polyethylene terephthalate (PET), glass, polydimethylsiloxane (PDMS), etc. First, AgNW samples on PDMS were characterized under bending and stretching. Then AgNW heaters and electrocardiogram (ECG) electrodes were fabricated to demonstrate the potential of this printing technique for AgNW-based flexible and stretchable devices.

  4. Highly Stretchable Non-volatile Nylon Thread Memory

    Science.gov (United States)

    Kang, Ting-Kuo

    2016-04-01

    Integration of electronic elements into textiles, to afford e-textiles, can provide an ideal platform for the development of lightweight, thin, flexible, and stretchable e-textiles. This approach will enable us to meet the demands of the rapidly growing market of wearable-electronics on arbitrary non-conventional substrates. However the actual integration of the e-textiles that undergo mechanical deformations during both assembly and daily wear or satisfy the requirements of the low-end applications, remains a challenge. Resistive memory elements can also be fabricated onto a nylon thread (NT) for e-textile applications. In this study, a simple dip-and-dry process using graphene-PEDOT:PSS (poly(3,4-ethylenedioxythiophene) polystyrene sulfonate) ink is proposed for the fabrication of a highly stretchable non-volatile NT memory. The NT memory appears to have typical write-once-read-many-times characteristics. The results show that an ON/OFF ratio of approximately 103 is maintained for a retention time of 106 s. Furthermore, a highly stretchable strain and a long-term digital-storage capability of the ON-OFF-ON states are demonstrated in the NT memory. The actual integration of the knitted NT memories into textiles will enable new design possibilities for low-cost and large-area e-textile memory applications.

  5. Extraordinarily Stretchable All-Carbon Collaborative Nanoarchitectures for Epidermal Sensors

    KAUST Repository

    Cai, Yichen

    2017-06-16

    Multifunctional microelectronic components featuring large stretchability, high sensitivity, high signal-to-noise ratio (SNR), and broad sensing range have attracted a huge surge of interest with the fast developing epidermal electronic systems. Here, the epidermal sensors based on all-carbon collaborative percolation network are demonstrated, which consist 3D graphene foam and carbon nanotubes (CNTs) obtained by two-step chemical vapor deposition processes. The nanoscaled CNT networks largely enhance the stretchability and SNR of the 3D microarchitectural graphene foams, endowing the strain sensor with a gauge factor as high as 35, a wide reliable sensing range up to 85%, and excellent cyclic stability (>5000 cycles). The flexible and reversible strain sensor can be easily mounted on human skin as a wearable electronic device for real-time and high accuracy detecting of electrophysiological stimuli and even for acoustic vibration recognition. The rationally designed all-carbon nanoarchitectures are scalable, low cost, and promising in practical applications requiring extraordinary stretchability and ultrahigh SNRs.

  6. Extraordinarily Stretchable All-Carbon Collaborative Nanoarchitectures for Epidermal Sensors

    KAUST Repository

    Cai, Yichen; Shen, Jie; Dai, Ziyang; Zang, Xiaoxian; Dong, Qiuchun; Guan, Guofeng; Li, Lain-Jong; Huang, Wei; Dong, Xiaochen

    2017-01-01

    Multifunctional microelectronic components featuring large stretchability, high sensitivity, high signal-to-noise ratio (SNR), and broad sensing range have attracted a huge surge of interest with the fast developing epidermal electronic systems. Here, the epidermal sensors based on all-carbon collaborative percolation network are demonstrated, which consist 3D graphene foam and carbon nanotubes (CNTs) obtained by two-step chemical vapor deposition processes. The nanoscaled CNT networks largely enhance the stretchability and SNR of the 3D microarchitectural graphene foams, endowing the strain sensor with a gauge factor as high as 35, a wide reliable sensing range up to 85%, and excellent cyclic stability (>5000 cycles). The flexible and reversible strain sensor can be easily mounted on human skin as a wearable electronic device for real-time and high accuracy detecting of electrophysiological stimuli and even for acoustic vibration recognition. The rationally designed all-carbon nanoarchitectures are scalable, low cost, and promising in practical applications requiring extraordinary stretchability and ultrahigh SNRs.

  7. Highly Stretchable and Conductive Superhydrophobic Coating for Flexible Electronics.

    Science.gov (United States)

    Su, Xiaojing; Li, Hongqiang; Lai, Xuejun; Chen, Zhonghua; Zeng, Xingrong

    2018-03-28

    Superhydrophobic materials integrating stretchability with conductivity have huge potential in the emerging application horizons such as wearable electronic sensors, flexible power storage apparatus, and corrosion-resistant circuits. Herein, a facile spraying method is reported to fabricate a durable superhydrophobic coating with excellent stretchable and electrical performance by combing 1-octadecanethiol-modified silver nanoparticles (M-AgNPs) with polystyrene- b-poly(ethylene- co-butylene)- b-polystyrene (SEBS) on a prestretched natural rubber (NR) substrate. The embedding of M-AgNPs in elastic SEBS matrix and relaxation of prestretched NR substrate construct hierarchical rough architecture and endow the coating with dense charge-transport pathways. The fabricated coating exhibits superhydrophobicity with water contact angle larger than 160° and a high conductivity with resistance of about 10 Ω. The coating not only maintains superhydrophobicity at low/high stretch ratio for the newly generated small/large protuberances but also responds to stretching and bending with good sensitivity, broad sensing range, and stable response cycles. Moreover, the coating exhibits excellent durability to heat and strong acid/alkali and mechanical forces including droplet impact, kneading, torsion, and repetitive stretching-relaxation. The findings conceivably stand out as a new tool to fabricate multifunctional superhydrophobic materials with excellent stretchability and conductivity for flexible electronics under wet or corrosive environments.

  8. Alkali-Resistant Quasi-Solid-State Electrolyte for Stretchable Supercapacitors.

    Science.gov (United States)

    Tang, Qianqiu; Wang, Wenqiang; Wang, Gengchao

    2016-10-05

    Research on stretchable energy-storage devices has been motivated by elastic electronics, and considerable research efforts have been devoted to the development of stretchable electrodes. However, stretchable electrolytes, another critical component in stretchable devices, have earned quite little attention, especially the alkali-resistant ones. Here, we reported a novel stretchable alkali-resistant electrolyte made of a polyolefin elastomer porous membrane supported potassium hydroxide-potassium polyacrylate (POE@KOH-PAAK). The as-prepared electrolyte shows a negligible plastic deformation even after 1000 stretching cycles at a strain of 150% as well as a high conductivity of 0.14 S cm -1 . It also exhibits excellent alkali resistance, which shows no obvious degradation of the mechanical performance after immersion in 2 M KOH for up to 2 weeks. To demonstrate its good properties, a high-performance stretchable supercapacitor is assembled using a carbon-nanotube-film-supported NiCo 2 O 4 (CNT@NiCo 2 O 4 ) as the cathode and Fe 2 O 3 (CNT@Fe 2 O 3 ) as the anode, proving great application promise of the stretchable alkali-resistant electrolyte in stretchable energy-storage devices.

  9. Editable Supercapacitors with Customizable Stretchability Based on Mechanically Strengthened Ultralong MnO2 Nanowire Composite.

    Science.gov (United States)

    Lv, Zhisheng; Luo, Yifei; Tang, Yuxin; Wei, Jiaqi; Zhu, Zhiqiang; Zhou, Xinran; Li, Wenlong; Zeng, Yi; Zhang, Wei; Zhang, Yanyan; Qi, Dianpeng; Pan, Shaowu; Loh, Xian Jun; Chen, Xiaodong

    2018-01-01

    Although some progress has been made on stretchable supercapacitors, traditional stretchable supercapacitors fabricated by predesigning structured electrodes for device assembling still lack the device-level editability and programmability. To adapt to wearable electronics with arbitrary configurations, it is highly desirable to develop editable supercapacitors that can be directly transferred into desirable shapes and stretchability. In this work, editable supercapacitors for customizable shapes and stretchability using electrodes based on mechanically strengthened ultralong MnO 2 nanowire composites are developed. A supercapacitor edited with honeycomb-like structure shows a specific capacitance of 227.2 mF cm -2 and can be stretched up to 500% without degradation of electrochemical performance, which is superior to most of the state-of-the-art stretchable supercapacitors. In addition, it maintains nearly 98% of the initial capacitance after 10 000 stretch-and-release cycles under 400% tensile strain. As a representative of concept for system integration, the editable supercapacitors are integrated with a strain sensor, and the system exhibits a stable sensing performance even under arm swing. Being highly stretchable, easily programmable, as well as connectable in series and parallel, an editable supercapacitor with customizable stretchability is promising to produce stylish energy storage devices to power various portable, stretchable, and wearable devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Stretchable, Twisted Conductive Microtubules for Wearable Computing, Robotics, Electronics, and Healthcare

    OpenAIRE

    Thanh Nho Do; Yon Visell

    2017-01-01

    Stretchable and flexible multifunctional electronic components, including sensors and actuators, have received increasing attention in robotics, electronics, wearable, and healthcare applications. Despite advances, it has remained challenging to design analogs of many electronic components to be highly stretchable, to be efficient to fabricate, and to provide control over electronic performance. Here, we describe highly elastic sensors and interconnects formed from thin, twisted conductive mi...

  11. Stretchable Electronic Sensors of Nanocomposite Network Films for Ultrasensitive Chemical Vapor Sensing.

    Science.gov (United States)

    Yan, Hong; Zhong, Mengjuan; Lv, Ze; Wan, Pengbo

    2017-11-01

    A stretchable, transparent, and body-attachable chemical sensor is assembled from the stretchable nanocomposite network film for ultrasensitive chemical vapor sensing. The stretchable nanocomposite network film is fabricated by in situ preparation of polyaniline/MoS 2 (PANI/MoS 2 ) nanocomposite in MoS 2 suspension and simultaneously nanocomposite deposition onto prestrain elastomeric polydimethylsiloxane substrate. The assembled stretchable electronic sensor demonstrates ultrasensitive sensing performance as low as 50 ppb, robust sensing stability, and reliable stretchability for high-performance chemical vapor sensing. The ultrasensitive sensing performance of the stretchable electronic sensors could be ascribed to the synergistic sensing advantages of MoS 2 and PANI, higher specific surface area, the reliable sensing channels of interconnected network, and the effectively exposed sensing materials. It is expected to hold great promise for assembling various flexible stretchable chemical vapor sensors with ultrasensitive sensing performance, superior sensing stability, reliable stretchability, and robust portability to be potentially integrated into wearable electronics for real-time monitoring of environment safety and human healthcare. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. A sewing-enabled stitch-and-transfer method for robust, ultra-stretchable, conductive interconnects

    International Nuclear Information System (INIS)

    Rahimi, Rahim; Ochoa, Manuel; Yu, Wuyang; Ziaie, Babak

    2014-01-01

    Fabricating highly stretchable and robust electrical interconnects at low-cost remains an unmet challenge in stretchable electronics. Previously reported stretchable interconnects require complicated fabrication processes with resulting devices exhibiting limited stretchability, poor reliability, and large gauge factors. Here, we demonstrate a novel sew-and-transfer method for rapid fabrication of low-cost, highly stretchable interconnects. Using a commercial sewing machine and double-thread stitch with one of the threads being water soluble polyvinyl alcohol (PVA), thin zigzag-pattern metallic wires are sewn into a polymeric film and are subsequently transferred onto a stretchable elastomeric substrate by dissolving PVA in warm water. The resulting structures exhibit extreme stretchability (exceeding 500% strain for a zigzag angle of 18 °) and robustness (capable of withstanding repeated stretch-and-release cycles of 15000 at 110% strain, 50000 at 55% strain, and  > 120000 at 30% strain without any noticeable change in resistance even at maximum strain levels). Using this technique, we demonstrate a stretchable inductive strain sensor for monitoring balloon expansion in a Foley urinary catheter capable of detecting the balloon diameter change from 9 mm to 38 mm with an average sensitivity of 4 nH/mm. (paper)

  13. Investigation on effect of methylene spacer in holographic grating formation in eosin containing polymethacrylates

    Energy Technology Data Exchange (ETDEWEB)

    Manickasundaram, S. [Department of Chemistry, Anna University, Sardar Vallabai Patel Road, Chennai 600025 (India); Kannan, P. [Department of Chemistry, Anna University, Sardar Vallabai Patel Road, Chennai 600025 (India)]. E-mail: pakannan@annauniv.edu; Deepa, S. [Centre for Laser Technology, Department of Physics, Anna University, Chennai 600025 (India); Palanisamy, P.K. [Centre for Laser Technology, Department of Physics, Anna University, Chennai 600025 (India)

    2007-01-15

    A new series of eosin dye based poly(alkyloxymethacrylate)s was synthesized with an even number of side-chain methylene spacers by a free radical addition polymerization method for holographic optical data storage applications. These polymers were characterized by UV, IR and {sup 1}H NMR spectroscopy. The glass transition temperature and thermal stability of the polymers were investigated by DSC and TGA, respectively. As the spacer length increases in the side-chain, Tg, Tm and thermal stability of the polymers decrease, while a reverse trend was observed with film forming ability of the polymers. The optical characterization of the polymers was investigated by forming holographic grating using an Argon ion laser. The grating diffraction efficiency was found to depend not only on the concentration of polymeric film but also on the spacer length of the polymers.

  14. Investigation on effect of methylene spacer in holographic grating formation in eosin containing polymethacrylates

    International Nuclear Information System (INIS)

    Manickasundaram, S.; Kannan, P.; Deepa, S.; Palanisamy, P.K.

    2007-01-01

    A new series of eosin dye based poly(alkyloxymethacrylate)s was synthesized with an even number of side-chain methylene spacers by a free radical addition polymerization method for holographic optical data storage applications. These polymers were characterized by UV, IR and 1 H NMR spectroscopy. The glass transition temperature and thermal stability of the polymers were investigated by DSC and TGA, respectively. As the spacer length increases in the side-chain, Tg, Tm and thermal stability of the polymers decrease, while a reverse trend was observed with film forming ability of the polymers. The optical characterization of the polymers was investigated by forming holographic grating using an Argon ion laser. The grating diffraction efficiency was found to depend not only on the concentration of polymeric film but also on the spacer length of the polymers

  15. Low crosstalk Arrayed Waveguide Grating with Cascaded Waveguide Grating Filter

    International Nuclear Information System (INIS)

    Deng Yang; Liu Yuan; Gao Dingshan

    2011-01-01

    We propose a highly compact and low crosstalk arrayed waveguide grating (AWG) with cascaded waveguide grating (CWGF). The side lobes of the silicon nanowire AWG, which are normally introduced by fabrication errors, can be effectively suppressed by the CWGF. And the crosstalk can be improved about 15dB.

  16. Molecularly Stretchable Electronics for Energy and Healthcare

    Science.gov (United States)

    Lipomi, Darren

    The term ``plastic electronics'' masks the wide range of mechanical behavior possessed by films of π-conjugated (semiconducting) small molecules and polymers. Such materials are promising for biosensors, large-area displays, low-energy lighting, and low-cost photovoltaic modules. There is also an apparent trade-off between electronic performance and mechanical compliance in films of some of the best-performing semiconducting polymers, which fracture at tensile strains not significantly greater than those at which conventional inorganic semiconductors fail. The design of intrinsically deformable electronic materials-i.e., imagine a semiconducting rubber band-would facilitate roll-to-roll production, mechanical robustness for potable applications, and conformal bonding to curved surfaces. This seminar describes my group's efforts to understand and control the structural parameters that influence the mechanical properties of π-conjugated polymers. The techniques we employ include synthetic chemistry, spectroscopy and microstructural characterization, computation from the molecular to continuum level, and electrical measurements of devices. A complex picture emerges for the interplay between molecular structure, the way the process of solidification influences the morphology, and how molecular structure and morphology combine to produce a film with a given modulus, elastic range, ductility, and toughness. We are also exploring ways to introduce other properties into organic semiconductors that are inspired by biological tissue. That is, not just elasticity and toughness, but also biodegradability and the capacity for self-repair. The seminar will also touch on our use of self-assembled metallic nanoislands on graphene for ultra-sensitive mechanical sensing using piezoresistive and ``piezoplasmonic'' mechanisms. The applications for these materials are in detecting human motion and measuring the mechanics of cardiac and musculoskeletal cells. My group is broadly

  17. Phase-shifted Bragg grating inscription in PMMA microstructured POF using 248 nm UV radiation

    OpenAIRE

    Pereira, L.; Pospori, A.; Antunes, Paulo; Domingues, Maria Fatima; Marques, S.; Bang, Ole; Webb, David J.; Marques, Carlos A.F.

    2017-01-01

    In this work we experimentally validate and characterize the first phase-shifted polymer optical fiber Bragg gratings (PS-POFBGs) produced using a single pulse from a 248 nm krypton fluoride laser. A single-mode poly (methyl methacrylate) optical fiber with a core doped with benzyl dimethyl ketal for photosensitivity improvement was used. A uniform phase mask customized for 850 nm grating inscription was used to inscribe these Bragg structures. The phase shift defect was created directly duri...

  18. Optical Fiber Grating based Sensors

    DEFF Research Database (Denmark)

    Michelsen, Susanne

    2003-01-01

    In this thesis differenct optical fiber gratings are used for sensor purposes. If a fiber with a core concentricity error (CCE) is used, a directional dependent bend sensor can be produced. The CCE direction can be determined by means of diffraction. This makes it possible to produce long......-period gratings in a fiber with a CCE direction parallel or perpendicular to the writing direction. The maximal bending sensitivity is independent on the writing direction, but the detailed bending response is different in the two cases. A temperature and strain sensor, based on a long-period grating and two...... sampled gratings, was produced and investigated. It is based on the different temperature and strain response of these gratings. Both a transfer matrix method and an overlap calculation is performed to explain the sensor response. Another type of sensor is based on tuning and modulation of a laser...

  19. Phase-shifted Bragg grating inscription in PMMA microstructured POF using 248 nm UV radiation

    DEFF Research Database (Denmark)

    Pereira, L.; Pospori, A.; Antunes, Paulo

    2017-01-01

    In this work we experimentally validate and characterize the first phase-shifted polymer optical fiber Bragg gratings (PS-POFBGs) produced using a single pulse from a 248 nm krypton fluoride laser. A single-mode poly (methyl methacrylate) optical fiber with a core doped with benzyl dimethyl ketal...... for photosensitivity improvement was used. A uniform phase mask customized for 850 nm grating inscription was used to inscribe these Bragg structures. The phase shift defect was created directly during the grating inscription process by placing a narrow blocking aperture in the center of the UV beam. The produced high...

  20. Enhancement of Light Absorption in Silicon Nanowire Photovoltaic Devices with Dielectric and Metallic Grating Structures.

    Science.gov (United States)

    Park, Jin-Sung; Kim, Kyoung-Ho; Hwang, Min-Soo; Zhang, Xing; Lee, Jung Min; Kim, Jungkil; Song, Kyung-Deok; No, You-Shin; Jeong, Kwang-Yong; Cahoon, James F; Kim, Sun-Kyung; Park, Hong-Gyu

    2017-12-13

    We report the enhancement of light absorption in Si nanowire photovoltaic devices with one-dimensional dielectric or metallic gratings that are fabricated by a damage-free, precisely aligning, polymer-assisted transfer method. Incorporation of a Si 3 N 4 grating with a Si nanowire effectively enhances the photocurrents for transverse-electric polarized light. The wavelength at which a maximum photocurrent is generated is readily tuned by adjusting the grating pitch. Moreover, the electrical properties of the nanowire devices are preserved before and after transferring the Si 3 N 4 gratings onto Si nanowires, ensuring that the quality of pristine nanowires is not degraded during the transfer. Furthermore, we demonstrate Si nanowire photovoltaic devices with Ag gratings using the same transfer method. Measurements on the fabricated devices reveal approximately 27.1% enhancement in light absorption compared to that of the same devices without the Ag gratings without any degradation of electrical properties. We believe that our polymer-assisted transfer method is not limited to the fabrication of grating-incorporated nanowire photovoltaic devices but can also be generically applied for the implementation of complex nanoscale structures toward the development of multifunctional optoelectronic devices.

  1. Nano-imprint gold grating as refractive index sensor

    International Nuclear Information System (INIS)

    Kumari, Sudha; Mohapatra, Saswat; Moirangthem, Rakesh S.

    2016-01-01

    Large scale of fabrication of plasmonic nanostructures has been a challenging task due to time consuming process and requirement of expensive nanofabrication tools such as electron beam lithography system, focused ion beam system, and extreme UV photolithography system. Here, we present a cost-effective fabrication technique so called soft nanoimprinting to fabricate nanostructures on the larger sample area. In our fabrication process, a commercially available optical DVD disc was used as a template which was imprinted on a polymer glass substrate to prepare 1D polymer nano-grating. A homemade nanoimprinting setup was used in this fabrication process. Further, a label-free refractive index sensor was developed by utilizing the properties of surface plasmon resonance (SPR) of a gold coated 1D polymer nano-grating. Refractive index sensing was tested by exposing different solutions of glycerol-water mixture on the surface of gold nano-grating. The calculated bulk refractive index sensitivity was found to be 751nm/RIU. We believed that our proposed SPR sensor could be a promising candidate for developing low-cost refractive index sensor with high sensitivity on a large scale.

  2. Rotated grating coupled surface plasmon resonance on wavelength-scaled shallow rectangular gratings

    Science.gov (United States)

    Szalai, A.; Szekeres, G.; Balázs, J.; Somogyi, A.; Csete, Maria

    2013-09-01

    Theoretical investigation of rotated grating coupling phenomenon was performed on a multilayer comprising 416-nmperiodic shallow rectangular polymer grating on bimetal film made of gold and silver layers. During the multilayer illumination by 532 nm wavelength p-polarized light the polar and azimuthal angles were varied. In presence of 0-35 nm, 0-50 nm and 15-50 nm thick polymer-layers at the valleys and hills splitting was observed on the dual-angle dependent reflectance in two regions: (i) close to 0° azimuthal angle corresponding to incidence plane parallel to the periodic pattern (P-orientation); and (ii) around ~33.5°/29°/30° azimuthal angle (C-orientation), in agreement with our previous experimental studies. The near-field study revealed that in P-orientation the E-field is enhanced at the glass side with p/2 periodicity at the first minimum appearing at 49°/50°/52° polar angles, and comprises maxima below both the valleys and hills; while E-field enhancement is observable both at the glass and polymer side with p-periodicity at the second minimum developing at 55°/63/64° tilting, comprising maxima intermittently below the valleys or above the hills. In Corientation coupled plasmonic modes are observable, involving modes propagating along the valleys at the secondary maxima appearing at ~35°/32°/32° azimuthal and ~49°/51°/56° polar angles, while modes confined along the polymer hills are observable at the primary minima, which are coupled most strongly at the ~31.5°/25°/28° azimuthal and ~55°/63°/66° polar angles. The secondary peak observable in C-orientation is proposed for biosensing applications, since the supported modes are confined along the valleys, where biomolecules prefer to attach.

  3. Enhancing relative permittivity by incorporating PDMS-PEG multiblock copolymers in binary polymer blends

    DEFF Research Database (Denmark)

    A Razak, Aliff Hisyam; Szabo, Peter; Skov, Anne Ladegaard

    Polydimethylsiloxane (PDMS) elastomers are well-known to be soft and highly stretchable, yet they never achieve maximum elongation when utilised as dielectric elastomers, simply because their dielectric permittivity remains rather low. Conversely, polyethyleneglycols (PEG) are not stretchable......, but they do possess high permittivity. Combining two such polymers in a block copolymer allows for further crosslinking and presents the possibility of substantial improvements in the actuation response of the resulting dielectric elastomer – if carefully designed. The objective is to synthesise a PDMS......, the discontinuity in PEG can be acquired and the relative permittivity (ε’) is significantly enhanced (60%) with 5wt% of PDMS-PEG block copolymer incorporated into the silicone elastomer....

  4. Lateral buckling and mechanical stretchability of fractal interconnects partially bonded onto an elastomeric substrate

    International Nuclear Information System (INIS)

    Fu, Haoran; Xu, Sheng; Rogers, John A.; Xu, Renxiao; Huang, Yonggang; Jiang, Jianqun; Zhang, Yihui

    2015-01-01

    Fractal-inspired designs for interconnects that join rigid, functional devices can ensure mechanical integrity in stretchable electronic systems under extreme deformations. The bonding configuration of such interconnects with the elastomer substrate is crucial to the resulting deformation modes, and therefore the stretchability of the entire system. In this study, both theoretical and experimental analyses are performed for postbuckling of fractal serpentine interconnects partially bonded to the substrate. The deformation behaviors and the elastic stretchability of such systems are systematically explored, and compared to counterparts that are not bonded at all to the substrate

  5. Scalable Manufacturing of Solderable and Stretchable Physiologic Sensing Systems.

    Science.gov (United States)

    Kim, Yun-Soung; Lu, Jesse; Shih, Benjamin; Gharibans, Armen; Zou, Zhanan; Matsuno, Kristen; Aguilera, Roman; Han, Yoonjae; Meek, Ann; Xiao, Jianliang; Tolley, Michael T; Coleman, Todd P

    2017-10-01

    Methods for microfabrication of solderable and stretchable sensing systems (S4s) and a scaled production of adhesive-integrated active S4s for health monitoring are presented. S4s' excellent solderability is achieved by the sputter-deposited nickel-vanadium and gold pad metal layers and copper interconnection. The donor substrate, which is modified with "PI islands" to become selectively adhesive for the S4s, allows the heterogeneous devices to be integrated with large-area adhesives for packaging. The feasibility for S4-based health monitoring is demonstrated by developing an S4 integrated with a strain gauge and an onboard optical indication circuit. Owing to S4s' compatibility with the standard printed circuit board assembly processes, a variety of commercially available surface mount chip components, such as the wafer level chip scale packages, chip resistors, and light-emitting diodes, can be reflow-soldered onto S4s without modifications, demonstrating the versatile and modular nature of S4s. Tegaderm-integrated S4 respiration sensors are tested for robustness for cyclic deformation, maximum stretchability, durability, and biocompatibility for multiday wear time. The results of the tests and demonstration of the respiration sensing indicate that the adhesive-integrated S4s can provide end users a way for unobtrusive health monitoring. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  6. Highly Stretchable, Biocompatible, Striated Substrate Made from Fugitive Glue

    Directory of Open Access Journals (Sweden)

    Wei Li

    2015-06-01

    Full Text Available We developed a novel substrate made from fugitive glue (styrenic block copolymer that can be used to analyze the effects of large strains on biological samples. The substrate has the following attributes: (1 It is easy to make from inexpensive components; (2 It is transparent and can be used in optical microscopy; (3 It is extremely stretchable as it can be stretched up to 700% strain; (4 It can be micro-molded, for example we created micro-ridges that are 6 μm high and 13 μm wide; (5 It is adhesive to biological fibers (we tested fibrin fibers, and can be used to uniformly stretch those fibers; (6 It is non-toxic to cells (we tested human mammary epithelial cells; (7 It can tolerate various salt concentrations up to 5 M NaCl and low (pH 0 and high (pH 14 pH values. Stretching of this extraordinary stretchable substrate is relatively uniform and thus, can be used to test multiple cells or fibers in parallel under the same conditions.

  7. Wearable Intrinsically Soft, Stretchable, Flexible Devices for Memories and Computing.

    Science.gov (United States)

    Rajan, Krishna; Garofalo, Erik; Chiolerio, Alessandro

    2018-01-27

    A recent trend in the development of high mass consumption electron devices is towards electronic textiles (e-textiles), smart wearable devices, smart clothes, and flexible or printable electronics. Intrinsically soft, stretchable, flexible, Wearable Memories and Computing devices (WMCs) bring us closer to sci-fi scenarios, where future electronic systems are totally integrated in our everyday outfits and help us in achieving a higher comfort level, interacting for us with other digital devices such as smartphones and domotics, or with analog devices, such as our brain/peripheral nervous system. WMC will enable each of us to contribute to open and big data systems as individual nodes, providing real-time information about physical and environmental parameters (including air pollution monitoring, sound and light pollution, chemical or radioactive fallout alert, network availability, and so on). Furthermore, WMC could be directly connected to human brain and enable extremely fast operation and unprecedented interface complexity, directly mapping the continuous states available to biological systems. This review focuses on recent advances in nanotechnology and materials science and pays particular attention to any result and promising technology to enable intrinsically soft, stretchable, flexible WMC.

  8. High-Density Stretchable Electrode Grids for Chronic Neural Recording.

    Science.gov (United States)

    Tybrandt, Klas; Khodagholy, Dion; Dielacher, Bernd; Stauffer, Flurin; Renz, Aline F; Buzsáki, György; Vörös, János

    2018-04-01

    Electrical interfacing with neural tissue is key to advancing diagnosis and therapies for neurological disorders, as well as providing detailed information about neural signals. A challenge for creating long-term stable interfaces between electronics and neural tissue is the huge mechanical mismatch between the systems. So far, materials and fabrication processes have restricted the development of soft electrode grids able to combine high performance, long-term stability, and high electrode density, aspects all essential for neural interfacing. Here, this challenge is addressed by developing a soft, high-density, stretchable electrode grid based on an inert, high-performance composite material comprising gold-coated titanium dioxide nanowires embedded in a silicone matrix. The developed grid can resolve high spatiotemporal neural signals from the surface of the cortex in freely moving rats with stable neural recording quality and preserved electrode signal coherence during 3 months of implantation. Due to its flexible and stretchable nature, it is possible to minimize the size of the craniotomy required for placement, further reducing the level of invasiveness. The material and device technology presented herein have potential for a wide range of emerging biomedical applications. © 2018 The Authors. Published by WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. Bragg gratings: Optical microchip sensors

    Science.gov (United States)

    Watts, Sam

    2010-07-01

    A direct UV writing technique that can create multiple Bragg gratings and waveguides in a planar silica-on-silicon chip is enabling sensing applications ranging from individual disposable sensors for biotechnology through to multiplexed sensor networks in pharmaceutical manufacturing.

  10. Waveguide silicon nitride grating coupler

    Science.gov (United States)

    Litvik, Jan; Dolnak, Ivan; Dado, Milan

    2016-12-01

    Grating couplers are one of the most used elements for coupling of light between optical fibers and photonic integrated components. Silicon-on-insulator platform provides strong confinement of light and allows high integration. In this work, using simulations we have designed a broadband silicon nitride surface grating coupler. The Fourier-eigenmode expansion and finite difference time domain methods are utilized in design optimization of grating coupler structure. The fully, single etch step grating coupler is based on a standard silicon-on-insulator wafer with 0.55 μm waveguide Si3N4 layer. The optimized structure at 1550 nm wavelength yields a peak coupling efficiency -2.6635 dB (54.16%) with a 1-dB bandwidth up to 80 nm. It is promising way for low-cost fabrication using complementary metal-oxide- semiconductor fabrication process.

  11. Encapsulation process for diffraction gratings.

    Science.gov (United States)

    Ratzsch, Stephan; Kley, Ernst-Bernhard; Tünnermann, Andreas; Szeghalmi, Adriana

    2015-07-13

    Encapsulation of grating structures facilitates an improvement of the optical functionality and/or adds mechanical stability to the fragile structure. Here, we introduce novel encapsulation process of nanoscale patterns based on atomic layer deposition and micro structuring. The overall size of the encapsulated structured surface area is only restricted by the size of the available microstructuring and coating devices; thus, overcoming inherent limitations of existing bonding processes concerning cleanliness, roughness, and curvature of the components. Finally, the process is demonstrated for a transmission grating. The encapsulated grating has 97.5% transmission efficiency in the -1st diffraction order for TM-polarized light, and is being limited by the experimental grating parameters as confirmed by rigorous coupled wave analysis.

  12. MEMS Bragg grating force sensor

    DEFF Research Database (Denmark)

    Reck, Kasper; Thomsen, Erik Vilain; Hansen, Ole

    2011-01-01

    We present modeling, design, fabrication and characterization of a new type of all-optical frequency modulated MEMS force sensor based on a mechanically amplified double clamped waveguide beam structure with integrated Bragg grating. The sensor is ideally suited for force measurements in harsh...... environments and for remote and distributed sensing and has a measured sensitivity of -14 nm/N, which is several times higher than what is obtained in conventional fiber Bragg grating force sensors. © 2011 Optical Society of America....

  13. Highly Stretchable Supercapacitors Based on Aligned Carbon Nanotube/Molybdenum Disulfide Composites.

    Science.gov (United States)

    Lv, Tian; Yao, Yao; Li, Ning; Chen, Tao

    2016-08-01

    Stretchable supercapacitors that can sustain their performance under unpredictable tensile force are important elements for practical applications of various portable and wearable electronics. However, the stretchability of most reported supercapacitors was often lower than 100 % because of the limitation of the electrodes used. Herein we developed all-solid-state supercapacitors with a stretchability as high as 240 % by using aligned carbon nanotube composites with compact structure as electrodes. By combined with pseudocapacitive molybdenum disulfide nanosheets, the newly developed supercapacitor showed a specific capacitance of 13.16 F cm(-3) , and also showed excellent cycling retention (98 %) after 10 000 charge-discharge cycles. This work also presents a general and effective approach in developing high-performance electrodes for flexible and stretchable electronics. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. 3D printed stretchable capacitive sensors for highly sensitive tactile and electrochemical sensing

    Science.gov (United States)

    Li, Kai; Wei, Hong; Liu, Wenguang; Meng, Hong; Zhang, Peixin; Yan, Chaoyi

    2018-05-01

    Developments of innovative strategies for the fabrication of stretchable sensors are of crucial importance for their applications in wearable electronic systems. In this work, we report the successful fabrication of stretchable capacitive sensors using a novel 3D printing method for highly sensitive tactile and electrochemical sensing applications. Unlike conventional lithographic or templated methods, the programmable 3D printing technique can fabricate complex device structures in a cost-effective and facile manner. We designed and fabricated stretchable capacitive sensors with interdigital and double-vortex designs and demonstrated their successful applications as tactile and electrochemical sensors. Especially, our stretchable sensors exhibited a detection limit as low as 1 × 10-6 M for NaCl aqueous solution, which could have significant potential applications when integrated in electronics skins.

  15. CMOS-Technology-Enabled Flexible and Stretchable Electronics for Internet of Everything Applications

    KAUST Repository

    Hussain, Aftab M.; Hussain, Muhammad Mustafa

    2015-01-01

    Flexible and stretchable electronics can dramatically enhance the application of electronics for the emerging Internet of Everything applications where people, processes, data and devices will be integrated and connected, to augment quality of life

  16. Stretchable Capacitors that Electrically Luminesce, Sense, and Actuate for Biomimetic Coloration

    Science.gov (United States)

    2017-10-31

    Reality (SIGGRAPH conference presentation; collaboration with NVIDIA Research). Potential Army Relevance: •Stretchable displays for visually indicating...with NVIDIA Research for using their Jetson micro AI computing device for gesture interpretation (paper in review). Resulting Journal Publications

  17. A self-healable and highly stretchable supercapacitor based on a dual crosslinked polyelectrolyte

    Science.gov (United States)

    Huang, Yan; Zhong, Ming; Huang, Yang; Zhu, Minshen; Pei, Zengxia; Wang, Zifeng; Xue, Qi; Xie, Xuming; Zhi, Chunyi

    2015-12-01

    Superior self-healability and stretchability are critical elements for the practical wide-scale adoption of personalized electronics such as portable and wearable energy storage devices. However, the low healing efficiency of self-healable supercapacitors and the small strain of stretchable supercapacitors are fundamentally limited by conventional polyvinyl alcohol-based acidic electrolytes, which are intrinsically neither self-healable nor highly stretchable. Here we report an electrolyte comprising polyacrylic acid dual crosslinked by hydrogen bonding and vinyl hybrid silica nanoparticles, which displays all superior functions and provides a solution to the intrinsic self-healability and high stretchability problems of a supercapacitor. Supercapacitors with this electrolyte are non-autonomic self-healable, retaining the capacitance completely even after 20 cycles of breaking/healing. These supercapacitors are stretched up to 600% strain with enhanced performance using a designed facile electrode fabrication procedure.

  18. Highly stretchable carbon nanotube transistors enabled by buckled ion gel gate dielectrics

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Meng-Yin; Chang, Tzu-Hsuan; Ma, Zhenqiang [Department of Electrical and Computer Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Zhao, Juan [School of Optoelectronic Information, University of Electronic Science and Technology of China, Chengdu 610054 (China); Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States); Xu, Feng; Jacobberger, Robert M.; Arnold, Michael S., E-mail: michael.arnold@wisc.edu [Department of Materials Science and Engineering, University of Wisconsin-Madison, Madison, Wisconsin 53706 (United States)

    2015-08-03

    Deformable field-effect transistors (FETs) are expected to facilitate new technologies like stretchable displays, conformal devices, and electronic skins. We previously demonstrated stretchable FETs based on buckled thin films of polyfluorene-wrapped semiconducting single-walled carbon nanotubes as the channel, buckled metal films as electrodes, and unbuckled flexible ion gel films as the dielectric. The FETs were stretchable up to 50% without appreciable degradation in performance before failure of the ion gel film. Here, we show that by buckling the ion gel, the integrity and performance of the nanotube FETs are extended to nearly 90% elongation, limited by the stretchability of the elastomer substrate. The FETs maintain an on/off ratio of >10{sup 4} and a field-effect mobility of 5 cm{sup 2} V{sup −1} s{sup −1} under elongation and demonstrate invariant performance over 1000 stretching cycles.

  19. Highly stretchable carbon nanotube transistors enabled by buckled ion gel gate dielectrics

    International Nuclear Information System (INIS)

    Wu, Meng-Yin; Chang, Tzu-Hsuan; Ma, Zhenqiang; Zhao, Juan; Xu, Feng; Jacobberger, Robert M.; Arnold, Michael S.

    2015-01-01

    Deformable field-effect transistors (FETs) are expected to facilitate new technologies like stretchable displays, conformal devices, and electronic skins. We previously demonstrated stretchable FETs based on buckled thin films of polyfluorene-wrapped semiconducting single-walled carbon nanotubes as the channel, buckled metal films as electrodes, and unbuckled flexible ion gel films as the dielectric. The FETs were stretchable up to 50% without appreciable degradation in performance before failure of the ion gel film. Here, we show that by buckling the ion gel, the integrity and performance of the nanotube FETs are extended to nearly 90% elongation, limited by the stretchability of the elastomer substrate. The FETs maintain an on/off ratio of >10 4 and a field-effect mobility of 5 cm 2 V −1 s −1 under elongation and demonstrate invariant performance over 1000 stretching cycles

  20. Analysis of the three-dimensional delamination behavior of stretchable electronics applications

    NARCIS (Netherlands)

    Sluis, van der O.; Timmermans, P.H.M.; Zanden, van der E.J.L.; Hoefnagels, J.P.M.; Ernst, L.J.

    2009-01-01

    Stretchable electronics offer potential application areasin biological implants interacting with human tissue. Furthermore, they facilitate increased design freedom of electronic products. Typical applications can be found in healthcare, wellness and functional clothes. A key requirement on these

  1. Stretchable surfaces with programmable 3D texture morphing for synthetic camouflaging skins

    Science.gov (United States)

    Pikul, J. H.; Li, S.; Bai, H.; Hanlon, R. T.; Cohen, I.; Shepherd, R. F.

    2017-10-01

    Technologies that use stretchable materials are increasingly important, yet we are unable to control how they stretch with much more sophistication than inflating balloons. Nature, however, demonstrates remarkable control of stretchable surfaces; for example, cephalopods can project hierarchical structures from their skin in milliseconds for a wide range of textural camouflage. Inspired by cephalopod muscular morphology, we developed synthetic tissue groupings that allowed programmable transformation of two-dimensional (2D) stretchable surfaces into target 3D shapes. The synthetic tissue groupings consisted of elastomeric membranes embedded with inextensible textile mesh that inflated to within 10% of their target shapes by using a simple fabrication method and modeling approach. These stretchable surfaces transform from flat sheets to 3D textures that imitate natural stone and plant shapes and camouflage into their background environments.

  2. Recent developments of truly stretchable thin film electronic and optoelectronic devices.

    Science.gov (United States)

    Zhao, Juan; Chi, Zhihe; Yang, Zhan; Chen, Xiaojie; Arnold, Michael S; Zhang, Yi; Xu, Jiarui; Chi, Zhenguo; Aldred, Matthew P

    2018-03-29

    Truly stretchable electronics, wherein all components themselves permit elastic deformation as the whole devices are stretched, exhibit unique advantages over other strategies, such as simple fabrication process, high integrity of entire components and intimate integration with curvilinear surfaces. In contrast to the stretchable devices using stretchable interconnectors to integrate with rigid active devices, truly stretchable devices are realized with or without intentionally employing structural engineering (e.g. buckling), and the whole device can be bent, twisted, or stretched to meet the demands for practical applications, which are beyond the capability of conventional flexible devices that can only bend or twist. Recently, great achievements have been made toward truly stretchable electronics. Here, the contribution of this review is an effort to provide a panoramic view of the latest progress concerning truly stretchable electronic devices, of which we give special emphasis to three kinds of thin film electronic and optoelectronic devices: (1) thin film transistors, (2) electroluminescent devices (including organic light-emitting diodes, light-emitting electrochemical cells and perovskite light-emitting diodes), and (3) photovoltaics (including organic photovoltaics and perovskite solar cells). We systematically discuss the device design and fabrication strategies, the origin of device stretchability and the relationship between the electrical and mechanical behaviors of the devices. We hope that this review provides a clear outlook of these attractive stretchable devices for a broad range of scientists and attracts more researchers to devote their time to this interesting research field in both industry and academia, thus encouraging more intelligent lifestyles for human beings in the coming future.

  3. Meltability and Stretchability of White Brined Cheese: Effect of Emulsifier Salts

    OpenAIRE

    Khaled Abu-Alruz; Ayman S. Mazahreh; Ali F. Al-Shawabkeh; Amer A. Omari; Jihad M. Quasem

    2009-01-01

    Problem statement: This study was based on the hypothesis that by adding low concentrations of emulsifier salts, may specifically act on the cross linking bonds of the protein matrix, to the original brine (storage medium) it would be possible to induce meltability and stretchability in white brined cheese. Approach: A new apparatus for measuring the actual stretchability was designed and constructed; measurements on different cheese samples proved its validity and reliability to measure stre...

  4. 3D Porous Sponge-Inspired Electrode for Stretchable Lithium-Ion Batteries.

    Science.gov (United States)

    Liu, Wei; Chen, Zheng; Zhou, Guangmin; Sun, Yongming; Lee, Hye Ryoung; Liu, Chong; Yao, Hongbin; Bao, Zhenan; Cui, Yi

    2016-05-01

    A stretchable Li4 Ti5 O12 anode and a LiFePO4 cathode with 80% stretchability are prepared using a 3D interconnected porous polydimethylsiloxane sponge based on sugar cubes. 82% and 91% capacity retention for anode and cathode are achieved after 500 stretch-release cycles. Slight capacity decay of 6% in the battery using the electrode in stretched state is observed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  5. 2.5D direct laser engraving of silicone microfluidic channels for stretchable electronics

    OpenAIRE

    Nagels, Steven; Deferme, Wim

    2017-01-01

    Stretchable and bendable sensors have become increasingly relevant as the technology behind them matures rapidly from lab based to industrially applicable production principles. In a broader sense, stretchable electronics promises to increase the way we are surrounded by and interact with our devices. Electronic circuits will be deployed in environments where we require them to dynamically flex, bend, stretch, compress, twist and - quite possibly - even fold; where they have to demonstrate a ...

  6. Skin-Attachable, Stretchable Electrochemical Sweat Sensor for Glucose and pH Detection.

    Science.gov (United States)

    Oh, Seung Yun; Hong, Soo Yeong; Jeong, Yu Ra; Yun, Junyeong; Park, Heun; Jin, Sang Woo; Lee, Geumbee; Oh, Ju Hyun; Lee, Hanchan; Lee, Sang-Soo; Ha, Jeong Sook

    2018-04-25

    As part of increased efforts to develop wearable healthcare devices for monitoring and managing physiological and metabolic information, stretchable electrochemical sweat sensors have been investigated. In this study, we report on the fabrication of a stretchable and skin-attachable electrochemical sensor for detecting glucose and pH in sweat. A patterned stretchable electrode was fabricated via layer-by-layer deposition of carbon nanotubes (CNTs) on top of patterned Au nanosheets (AuNS) prepared by filtration onto stretchable substrate. For the detection of glucose and pH, CoWO 4 /CNT and polyaniline/CNT nanocomposites were coated onto the CNT-AuNS electrodes, respectively. A reference electrode was prepared via chlorination of silver nanowires. Encapsulation of the stretchable sensor with sticky silbione led to a skin-attachable sweat sensor. Our sensor showed high performance with sensitivities of 10.89 μA mM -1 cm -2 and 71.44 mV pH -1 for glucose and pH, respectively, with mechanical stability up to 30% stretching and air stability for 10 days. The sensor also showed good adhesion even to wet skin, allowing the detection of glucose and pH in sweat from running while being attached onto the skin. This work suggests the application of our stretchable and skin-attachable electrochemical sensor to health management as a high-performance healthcare wearable device.

  7. Stretchable, Transparent, and Stretch-Unresponsive Capacitive Touch Sensor Array with Selectively Patterned Silver Nanowires/Reduced Graphene Oxide Electrodes.

    Science.gov (United States)

    Choi, Tae Young; Hwang, Byeong-Ung; Kim, Bo-Yeong; Trung, Tran Quang; Nam, Yun Hyoung; Kim, Do-Nyun; Eom, Kilho; Lee, Nae-Eung

    2017-05-31

    Stretchable and transparent touch sensors are essential input devices for future stretchable transparent electronics. Capacitive touch sensors with a simple structure of only two electrodes and one dielectric are an established technology in current rigid electronics. However, the development of stretchable and transparent capacitive touch sensors has been limited due to changes in capacitance resulting from dimensional changes in elastomeric dielectrics and difficulty in obtaining stretchable transparent electrodes that are stable under large strains. Herein, a stretch-unresponsive stretchable and transparent capacitive touch sensor array was demonstrated by employing stretchable and transparent electrodes with a simple selective-patterning process and by carefully selecting dielectric and substrate materials with low strain responsivity. A selective-patterning process was used to embed a stretchable and transparent silver nanowires/reduced graphene oxide (AgNWs/rGO) electrode line into a polyurethane (PU) dielectric layer on a polydimethylsiloxane (PDMS) substrate using oxygen plasma treatment. This method provides the ability to directly fabricate thin film electrode lines on elastomeric substrates and can be used in conventional processes employed in stretchable electronics. We used a dielectric (PU) with a Poisson's ratio smaller than that of the substrate (PDMS), which prevented changes in the capacitance resulting from stretching of the sensor. The stretch-unresponsive touch sensing capability of our transparent and stretchable capacitive touch sensor has great potential in wearable electronics and human-machine interfaces.

  8. Cryogenic Etching of High Aspect Ratio 400 nm Pitch Silicon Gratings.

    Science.gov (United States)

    Miao, Houxun; Chen, Lei; Mirzaeimoghri, Mona; Kasica, Richard; Wen, Han

    2016-10-01

    The cryogenic process and Bosch process are two widely used processes for reactive ion etching of high aspect ratio silicon structures. This paper focuses on the cryogenic deep etching of 400 nm pitch silicon gratings with various etching mask materials including polymer, Cr, SiO 2 and Cr-on-polymer. The undercut is found to be the key factor limiting the achievable aspect ratio for the direct hard masks of Cr and SiO 2 , while the etch selectivity responds to the limitation of the polymer mask. The Cr-on-polymer mask provides the same high selectivity as Cr and reduces the excessive undercut introduced by direct hard masks. By optimizing the etching parameters, we etched a 400 nm pitch grating to ≈ 10.6 μ m depth, corresponding to an aspect ratio of ≈ 53.

  9. Thermal and Structural Analysis of FIMS Grating

    Directory of Open Access Journals (Sweden)

    K.-I. Seon

    2001-06-01

    Full Text Available Far ultraviolet IMaging Spectrograph (FIMS should be designed to maintain its structural stability and to minimize optical performance degradation in launch and in operation enviroments. The structural and thermal analyzes of grating and grating mount system, which are directly related to FIMS optical performance, was performed using finite element method. The grating mount was made to keep the grating stress down, while keeping the natural frequency of the grating mount higher than 100 Hz. Transient and static thermal analyzes were also performed and the results shows that the thermal stress on the grating can be attenuated sufficiently The optical performance variation due to temperature variation was within the allowed range.

  10. Stop grating for perfect replication of micro Fresnel lens by thermal imprinting

    International Nuclear Information System (INIS)

    Gao, Yulong; Lin, Jie; Jin, Peng; Tan, Jiubin; Davies, Graham; Prewett, Philip D

    2012-01-01

    A stop grating concept is proposed to improve polymer filling in the thermal imprinting of a micro Fresnel lens structure. The stop grating consists of line and space structures outside the Fresnel lens pattern zone area. The experimental results have proved that the stop grating can help to achieve the complete filling of a mold, at the same time acting as a stop to prevent possible damage to the mold surface relief structures during imprinting press. A computer simulation was carried out to identify the phenomena of micro-holes at the edge of imprinted pattern. By removing the cavity between the pattern area and stop grating, perfect imprinting results have been achieved. (paper)

  11. A strain-isolation design for stretchable electronics

    Science.gov (United States)

    Wu, Jian; Li, Ming; Chen, Wei-Qiu; Kim, Dae-Hyeong; Kim, Yun-Soung; Huang, Yong-Gang; Hwang, Keh-Chih; Kang, Zhan; Rogers, John A.

    2010-12-01

    Stretchable electronics represents a direction of recent development in next-generation semiconductor devices. Such systems have the potential to offer the performance of conventional wafer-based technologies, but they can be stretched like a rubber band, twisted like a rope, bent over a pencil, and folded like a piece of paper. Isolating the active devices from strains associated with such deformations is an important aspect of design. One strategy involves the shielding of the electronics from deformation of the substrate through insertion of a compliant adhesive layer. This paper establishes a simple, analytical model and validates the results by the finite element method. The results show that a relatively thick, compliant adhesive is effective to reduce the strain in the electronics, as is a relatively short film.

  12. Stretchable, Adhesion-Tunable Dry Adhesive by Surface Wrinkling

    KAUST Repository

    Jeong, Hoon Eui

    2010-02-16

    We introduce a simple yet robust method of fabricating a stretchable, adhesion-tunable dry adhesive by combining replica molding and surface wrinkling. By utilizing a thin, wrinkled polydimethyl siloxane (PDMS) sheet with a thickness of 1 mm with built-in micropillars, active, dynamic control of normal and shear adhesion was achieved. Relatively strong normal (∼10.8 N/cm2) and shear adhesion (∼14.7 N/cm2) forces could be obtained for a fully extended (strained) PDMS sheet (prestrain of∼3%), whereas the forces could be rapidly reduced to nearly zero once the prestrain was released (prestrain of ∼0.5%). Moreover, durability tests demonstrated that the adhesion strength in both the normal and shear directions was maintained over more than 100 cycles of attachment and detachment. © 2010 American Chemical Society.

  13. Bubble inductors: Pneumatic tuning of a stretchable inductor

    Science.gov (United States)

    Lazarus, Nathan; Bedair, Sarah S.

    2018-05-01

    From adaptive matching networks in power systems to channel selectable RF filters and circuitry, tunable inductors are fundamental components for circuits requiring reconfigurability. Here we demonstrate a new continuously tunable inductor based on physically stretching the inductor traces themselves. Liquid-metal-based stretchable conductors are wrapped around a pneumatic bubble actuator, allowing the inductor to be collapsed or expanded by application of pressure. In vacuum the bubble collapses, bringing the loop area to nearly zero, while positive pressure brings a dramatic increase in area and loop inductance. Using this approach, the inductor demonstrated in this work was able to achieve a tuning ratio of 2.6 with 1-2 second response time. With conductors available that can stretch by hundreds of percent, this technique is promising for very large tuning ratios in continuously tunable inductors.

  14. Stretchable, Adhesion-Tunable Dry Adhesive by Surface Wrinkling

    KAUST Repository

    Jeong, Hoon Eui; Kwak, Moon Kyu; Suh, Kahp Y.

    2010-01-01

    We introduce a simple yet robust method of fabricating a stretchable, adhesion-tunable dry adhesive by combining replica molding and surface wrinkling. By utilizing a thin, wrinkled polydimethyl siloxane (PDMS) sheet with a thickness of 1 mm with built-in micropillars, active, dynamic control of normal and shear adhesion was achieved. Relatively strong normal (∼10.8 N/cm2) and shear adhesion (∼14.7 N/cm2) forces could be obtained for a fully extended (strained) PDMS sheet (prestrain of∼3%), whereas the forces could be rapidly reduced to nearly zero once the prestrain was released (prestrain of ∼0.5%). Moreover, durability tests demonstrated that the adhesion strength in both the normal and shear directions was maintained over more than 100 cycles of attachment and detachment. © 2010 American Chemical Society.

  15. Anomalous Stretchable Conductivity Using an Engineered Tricot Weave.

    Science.gov (United States)

    Lee, Yong-Hee; Kim, Yoonseob; Lee, Tae-Ik; Lee, Inhwa; Shin, Jaeho; Lee, Hyun Soo; Kim, Taek-Soo; Choi, Jang Wook

    2015-12-22

    Robust electric conduction under stretching motions is a key element in upcoming wearable electronic devices but is fundamentally very difficult to achieve because percolation pathways in conductive media are subject to collapse upon stretching. Here, we report that this fundamental challenge can be overcome by using a parameter uniquely available in textiles, namely a weaving structure. A textile structure alternately interwoven with inelastic and elastic yarns, achieved via a tricot weave, possesses excellent elasticity (strain up to 200%) in diagonal directions. When this textile is coated with conductive nanomaterials, proper textile engineering allows the textile to obtain an unprecedented 7-fold conductivity increase, with conductivity reaching 33,000 S cm(-1), even at 130% strain, due to enhanced interyarn contacts. The observed stretching conductivity can be described well using a modified 3D percolation theory that reflects the weaving effect and is also utilized for stretchable electronic interconnects and supercapacitors with high performance.

  16. Flexible and Stretchable Energy Storage: Recent Advances and Future Perspectives.

    Science.gov (United States)

    Liu, Wei; Song, Min-Sang; Kong, Biao; Cui, Yi

    2017-01-01

    Energy-storage technologies such as lithium-ion batteries and supercapacitors have become fundamental building blocks in modern society. Recently, the emerging direction toward the ever-growing market of flexible and wearable electronics has nourished progress in building multifunctional energy-storage systems that can be bent, folded, crumpled, and stretched while maintaining their electrochemical functions under deformation. Here, recent progress and well-developed strategies in research designed to accomplish flexible and stretchable lithium-ion batteries and supercapacitors are reviewed. The challenges of developing novel materials and configurations with tailored features, and in designing simple and large-scaled manufacturing methods that can be widely utilized are considered. Furthermore, the perspectives and opportunities for this emerging field of materials science and engineering are also discussed. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Multifunctional Polymer-Based Graphene Foams with Buckled Structure and Negative Poisson’s Ratio

    Science.gov (United States)

    Dai, Zhaohe; Weng, Chuanxin; Liu, Luqi; Hou, Yuan; Zhao, Xuanliang; Kuang, Jun; Shi, Jidong; Wei, Yueguang; Lou, Jun; Zhang, Zhong

    2016-01-01

    In this study, we report the polymer-based graphene foams through combination of bottom-up assembly and simple triaxially buckled structure design. The resulting polymer-based graphene foams not only effectively transfer the functional properties of graphene, but also exhibit novel negative Poisson’s ratio (NPR) behaviors due to the presence of buckled structure. Our results show that after the introduction of buckled structure, improvement in stretchability, toughness, flexibility, energy absorbing ability, hydrophobicity, conductivity, piezoresistive sensitivity and crack resistance could be achieved simultaneously. The combination of mechanical properties, multifunctional performance and unusual deformation behavior would lead to the use of our polymer-based graphene foams for a variety of novel applications in future such as stretchable capacitors or conductors, sensors and oil/water separators and so on. PMID:27608928

  18. Exploiting a Transmission Grating Spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Ronald E. Bell

    2004-12-08

    The availability of compact transmission grating spectrometers now allows an attractive and economical alternative to the more familiar Czerny-Turner configuration for many high-temperature plasma applications. Higher throughput is obtained with short focal length refractive optics and stigmatic imaging. Many more spectra can be obtained with a single spectrometer since smaller, more densely packed optical input fibers can be used. Multiple input slits, along with a bandpass filter, can be used to maximize the number of spectra per detector, providing further economy. Curved slits can correct for the strong image curvature of the short focal length optics. Presented here are the governing grating equations for both standard and high-dispersion transmission gratings, defining dispersion, image curvature, and desired slit curvature, that can be used in the design of improved plasma diagnostics.

  19. Exploiting a Transmission Grating Spectrometer

    International Nuclear Information System (INIS)

    Bell, Ronald E.

    2004-01-01

    The availability of compact transmission grating spectrometers now allows an attractive and economical alternative to the more familiar Czerny-Turner configuration for many high-temperature plasma applications. Higher throughput is obtained with short focal length refractive optics and stigmatic imaging. Many more spectra can be obtained with a single spectrometer since smaller, more densely packed optical input fibers can be used. Multiple input slits, along with a bandpass filter, can be used to maximize the number of spectra per detector, providing further economy. Curved slits can correct for the strong image curvature of the short focal length optics. Presented here are the governing grating equations for both standard and high-dispersion transmission gratings, defining dispersion, image curvature, and desired slit curvature, that can be used in the design of improved plasma diagnostics

  20. Blazed vector grating liquid crystal cells with photocrosslinkable polymeric alignment films fabricated by one-step polarizer rotation method

    Science.gov (United States)

    Kawai, Kotaro; Kuzuwata, Mitsuru; Sasaki, Tomoyuki; Noda, Kohei; Kawatsuki, Nobuhiro; Ono, Hiroshi

    2014-12-01

    Blazed vector grating liquid crystal (LC) cells, in which the directors of low-molar-mass LCs are antisymmetrically distributed, were fabricated by one-step exposure of an empty glass cell inner-coated with a photocrosslinkable polymer LC (PCLC) to UV light. By adopting a LC cell structure, twisted nematic (TN) and homogeneous (HOMO) alignments were obtained in the blazed vector grating LC cells. Moreover, the diffraction efficiency of the blazed vector grating LC cells was greatly improved by increasing the thickness of the device in comparison with that of a blazed vector grating with a thin film structure obtained in our previous study. In addition, the diffraction efficiency and polarization states of ±1st-order diffracted beams from the resultant blazed vector grating LC cells were controlled by designing a blazed pattern in the alignment films, and these diffraction properties were well explained on the basis of Jones calculus and the elastic continuum theory of nematic LCs.

  1. Bragg gratings inscription in step-index PMMA optical fiber by femtosecond laser pulses at 400 nm

    Science.gov (United States)

    Hu, X.; Kinet, D.; Chah, K.; Mégret, P.; Caucheteur, C.

    2016-05-01

    In this paper, we report photo-inscription of uniform Bragg gratings in trans-4-stilbenemethanol-doped photosensitive step-index polymer optical fiber. Gratings were produced at ~1575 nm by the phase mask technique with a femtosecond laser emitting at 400 nm with different average optical powers (8 mW, 13 mW and 20 mW). The grating growth dynamics in transmission were monitored during the manufacturing process, showing that the grating grows faster with higher power. Using 20 mW laser beam power, the reflectivity reaches 94 % (8 dB transmission loss) in 70 seconds. Finally, the gratings were characterized in temperature in the range 20 - 45 °C. The thermal sensitivity has been computed equal to - 86.6 pm/°C.

  2. Pulsed recording of anisotropy and holographic polarization gratings in azo-polymethacrylates with different molecular architectures

    DEFF Research Database (Denmark)

    Forcén, Patricia; Oriol, Luis; Alcala, Rafael

    2008-01-01

    Recording of anisotropy and holographic polarization gratings using 532 nm, 4 ns light pulses has been carried out in thin films of polymers with the same azobenzene content (20 wt %) and different molecular architectures. Random and block copolymers comprising azobenzene and methylmethacrylate (...

  3. Enhanced Raman scattering in porous silicon grating.

    Science.gov (United States)

    Wang, Jiajia; Jia, Zhenhong; Lv, Changwu

    2018-03-19

    The enhancement of Raman signal on monocrystalline silicon gratings with varying groove depths and on porous silicon grating were studied for a highly sensitive surface enhanced Raman scattering (SERS) response. In the experiment conducted, porous silicon gratings were fabricated. Silver nanoparticles (Ag NPs) were then deposited on the porous silicon grating to enhance the Raman signal of the detective objects. Results show that the enhancement of Raman signal on silicon grating improved when groove depth increased. The enhanced performance of Raman signal on porous silicon grating was also further improved. The Rhodamine SERS response based on Ag NPs/ porous silicon grating substrates was enhanced relative to the SERS response on Ag NPs/ porous silicon substrates. Ag NPs / porous silicon grating SERS substrate system achieved a highly sensitive SERS response due to the coupling of various Raman enhancement factors.

  4. Grating-Coupled Waveguide Cloaking

    International Nuclear Information System (INIS)

    Wang Jia-Fu; Qu Shao-Bo; Ma Hua; Wang Cong-Min; Wang Xin-Hua; Zhou Hang; Xu Zhuo; Xia Song

    2012-01-01

    Based on the concept of a grating-coupled waveguide (GCW), a new strategy for realizing EM cloaking is presented. Using metallic grating, incident waves are firstly coupled into the effective waveguide and then decoupled into free space behind, enabling EM waves to pass around the obstacle. Phase compensation in the waveguide keeps the wave-front shape behind the obstacle unchanged. Circular, rectangular and triangular cloaks are presented to verify the robustness of the GCW cloaking. Electric field animations and radar cross section (RCS) comparisons convincingly demonstrate the cloaking effect

  5. Embedded high-contrast distributed grating structures

    Science.gov (United States)

    Zubrzycki, Walter J.; Vawter, Gregory A.; Allerman, Andrew A.

    2002-01-01

    A new class of fabrication methods for embedded distributed grating structures is claimed, together with optical devices which include such structures. These new methods are the only known approach to making defect-free high-dielectric contrast grating structures, which are smaller and more efficient than are conventional grating structures.

  6. Hybrid grating reflectors: Origin of ultrabroad stopband

    DEFF Research Database (Denmark)

    Park, Gyeong Cheol; Taghizadeh, Alireza; Chung, Il-Sug

    2016-01-01

    Hybrid grating (HG) reflectors with a high-refractive-index cap layer added onto a high contrast grating (HCG) provide a high reflectance close to 100% over a broader wavelength range than HCGs. The combination of a cap layer and a grating layer brings a strong Fabry-Perot (FP) resonance as well ...

  7. Fabrication Approaches to Interconnect Based Devices for Stretchable Electronics: A Review

    Directory of Open Access Journals (Sweden)

    Steven Nagels

    2018-03-01

    Full Text Available Stretchable electronics promise to naturalize the way that we are surrounded by and interact with our devices. Sensors that can stretch and bend furthermore have become increasingly relevant as the technology behind them matures rapidly from lab-based workflows to industrially applicable production principles. Regardless of the specific materials used, creating stretchable conductors involves either the implementation of strain reliefs through insightful geometric patterning, the dispersion of stiff conductive filler in an elastomeric matrix, or the employment of intrinsically stretchable conductive materials. These basic principles however have spawned a myriad of materials systems wherein future application engineers need to find their way. This paper reports a literature study on the spectrum of different approaches towards stretchable electronics, discusses standardization of characteristic tests together with their reports and estimates matureness for industry. Patterned copper foils that are embedded in elastomeric sheets, which are closest to conventional electronic circuits processing, make up one end of the spectrum. Furthest from industry are the more recent circuits based on intrinsically stretchable liquid metals. These show extremely promising results, however, as a technology, liquid metal is not mature enough to be adapted. Printing makes up the transition between both ends, and is also well established on an industrial level, but traditionally not linked to creating electronics. Even though a certain level of maturity was found amongst the approaches that are reviewed herein, industrial adaptation for consumer electronics remains unpredictable without a designated break-through commercial application.

  8. Fabrication Approaches to Interconnect Based Devices for Stretchable Electronics: A Review.

    Science.gov (United States)

    Nagels, Steven; Deferme, Wim

    2018-03-03

    Stretchable electronics promise to naturalize the way that we are surrounded by and interact with our devices. Sensors that can stretch and bend furthermore have become increasingly relevant as the technology behind them matures rapidly from lab-based workflows to industrially applicable production principles. Regardless of the specific materials used, creating stretchable conductors involves either the implementation of strain reliefs through insightful geometric patterning, the dispersion of stiff conductive filler in an elastomeric matrix, or the employment of intrinsically stretchable conductive materials. These basic principles however have spawned a myriad of materials systems wherein future application engineers need to find their way. This paper reports a literature study on the spectrum of different approaches towards stretchable electronics, discusses standardization of characteristic tests together with their reports and estimates matureness for industry. Patterned copper foils that are embedded in elastomeric sheets, which are closest to conventional electronic circuits processing, make up one end of the spectrum. Furthest from industry are the more recent circuits based on intrinsically stretchable liquid metals. These show extremely promising results, however, as a technology, liquid metal is not mature enough to be adapted. Printing makes up the transition between both ends, and is also well established on an industrial level, but traditionally not linked to creating electronics. Even though a certain level of maturity was found amongst the approaches that are reviewed herein, industrial adaptation for consumer electronics remains unpredictable without a designated break-through commercial application.

  9. Highly stretchable and conductive fibers enabled by liquid metal dip-coating

    Science.gov (United States)

    Zhang, Qiang; Roach, Devin J.; Geng, Luchao; Chen, Haosen; Qi, H. Jerry; Fang, Daining

    2018-03-01

    Highly stretchable and conductive fibers have been fabricated by dip-coating of a layer of liquid metal (eutectic gallium indium, EGaIn) on printed silicone elastomer filaments. This fabrication method exploits a nanolayer of oxide skin that rapidly forms on the surface of EGaIn when exposed to air. Through dip-coating, the sticky nature of the oxide skin leads to the formation of a thin EGaIn coating (˜5 μm thick) on the originally nonconductive filaments and renders these fibers excellent conductivity. Electrical characterization shows that the fiber resistance increases moderately as the fiber elongates but always maintains conductivity even when stretched by 800%. Besides this, these fibers possess good cyclic electrical stability with little degradation after hundreds of stretching cycles, which makes them an excellent candidate for stretchable conductors. We then demonstrate a highly stretchable LED circuit as well as a conductive stretchable net that extends the 1D fibers into a 2D configuration. These examples demonstrate potential applications for topologically complex stretchable electronics.

  10. Stretchable, Twisted Conductive Microtubules for Wearable Computing, Robotics, Electronics, and Healthcare.

    Science.gov (United States)

    Do, Thanh Nho; Visell, Yon

    2017-05-11

    Stretchable and flexible multifunctional electronic components, including sensors and actuators, have received increasing attention in robotics, electronics, wearable, and healthcare applications. Despite advances, it has remained challenging to design analogs of many electronic components to be highly stretchable, to be efficient to fabricate, and to provide control over electronic performance. Here, we describe highly elastic sensors and interconnects formed from thin, twisted conductive microtubules. These devices consist of twisted assemblies of thin, highly stretchable (>400%) elastomer tubules filled with liquid conductor (eutectic gallium indium, EGaIn), and fabricated using a simple roller coating process. As we demonstrate, these devices can operate as multimodal sensors for strain, rotation, contact force, or contact location. We also show that, through twisting, it is possible to control their mechanical performance and electronic sensitivity. In extensive experiments, we have evaluated the capabilities of these devices, and have prototyped an array of applications in several domains of stretchable and wearable electronics. These devices provide a novel, low cost solution for high performance stretchable electronics with broad applications in industry, healthcare, and consumer electronics, to emerging product categories of high potential economic and societal significance.

  11. 3D-Structured Stretchable Strain Sensors for Out-of-Plane Force Detection.

    Science.gov (United States)

    Liu, Zhiyuan; Qi, Dianpeng; Leow, Wan Ru; Yu, Jiancan; Xiloyannnis, Michele; Cappello, Leonardo; Liu, Yaqing; Zhu, Bowen; Jiang, Ying; Chen, Geng; Masia, Lorenzo; Liedberg, Bo; Chen, Xiaodong

    2018-05-17

    Stretchable strain sensors, as the soft mechanical interface, provide the key mechanical information of the systems for healthcare monitoring, rehabilitation assistance, soft exoskeletal devices, and soft robotics. Stretchable strain sensors based on 2D flat film have been widely developed to monitor the in-plane force applied within the plane where the sensor is placed. However, to comprehensively obtain the mechanical feedback, the capability to detect the out-of-plane force, caused by the interaction outside of the plane where the senor is located, is needed. Herein, a 3D-structured stretchable strain sensor is reported to monitor the out-of-plane force by employing 3D printing in conjunction with out-of-plane capillary force-assisted self-pinning of carbon nanotubes. The 3D-structured sensor possesses large stretchability, multistrain detection, and strain-direction recognition by one single sensor. It is demonstrated that out-of-plane forces induced by the air/fluid flow are reliably monitored and intricate flow details are clearly recorded. The development opens up for the exploration of next-generation 3D stretchable sensors for electronic skin and soft robotics. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Ultra-Stretchable Piezoelectric Nanogenerators via Large-Scale Aligned Fractal Inspired Micro/Nanofibers

    Directory of Open Access Journals (Sweden)

    Yongqing Duan

    2017-12-01

    Full Text Available Stretchable nanogenerators that directly generate electricity are promising for a wide range of applications in wearable electronics. However, the stretchability of the devices has been a long-standing challenge. Here we present a newly-designed ultra-stretchable nanogenerator based on fractal-inspired piezoelectric nanofibers and liquid metal electrodes that can withstand strain as large as 200%. The large-scale fractal poly(vinylidene fluoride (PVDF micro/nanofibers are fabricated by combination of helix electrohydrodynamic printing (HE-Printing and buckling-driven self-assembly. HE-Printing exploits “whipping/buckling” instability of electrospinning to deposit serpentine fibers with diverse geometries in a programmable, accurately positioned, and individually-controlled manner. Self-organized buckling utilizes the driven force from the prestrained elastomer to assemble serpentine fibers into ultra-stretchable fractal inspired architecture. The nanogenerator with embedded fractal PVDF fibers and liquid-metal microelectrodes demonstrates high stretchability (>200% and electricity (currents >200 nA, it can harvest energy from all directions by arbitrary mechanical motion, and the rectified output has been applied to charge the commercial capacitor and drive LEDs, which enables wearable electronics applications in sensing and energy harvesting.

  13. The grating as an accelerating structure

    International Nuclear Information System (INIS)

    Fernow, R.C.

    1991-02-01

    This report considers the use of a diffraction grating as an accelerating structure for charged particle beams. We examine the functional dependence of the electromagnetic fields above the surface of a grating. Calculations are made of the strength of the accelerating modes for structures with π and 2π phase advance per period and for incident waves polarized with either the E or H vector along the grooves of the grating. We consider examples of using gratings in a laser linac and in a grating lens. We also briefly examine previous results published about this subject. 36 refs

  14. Curved VPH gratings for novel spectrographs

    Science.gov (United States)

    Clemens, J. Christopher; O'Donoghue, Darragh; Dunlap, Bart H.

    2014-07-01

    The introduction of volume phase holographic (VPH) gratings into astronomy over a decade ago opened new possibilities for instrument designers. In this paper we describe an extension of VPH grating technology that will have applications in astronomy and beyond: curved VPH gratings. These devices can disperse light while simultaneously correcting aberrations. We have designed and manufactured two different kinds of convex VPH grating prototypes for use in off-axis reflecting spectrographs. One type functions in transmission and the other in reflection, enabling Offnerstyle spectrographs with the high-efficiency and low-cost advantages of VPH gratings. We will discuss the design process and the tools required for modelling these gratings along with the recording layout and process steps required to fabricate them. We will present performance data for the first convex VPH grating produced for an astronomical spectrograph.

  15. Stretchable Persistent Spin Helices in GaAs Quantum Wells

    Science.gov (United States)

    Dettwiler, Florian; Fu, Jiyong; Mack, Shawn; Weigele, Pirmin J.; Egues, J. Carlos; Awschalom, David D.; Zumbühl, Dominik M.

    2017-07-01

    The Rashba and Dresselhaus spin-orbit (SO) interactions in 2D electron gases act as effective magnetic fields with momentum-dependent directions, which cause spin decay as the spins undergo arbitrary precessions about these randomly oriented SO fields due to momentum scattering. Theoretically and experimentally, it has been established that by fine-tuning the Rashba α and renormalized Dresselhaus β couplings to equal fixed strengths α =β , the total SO field becomes unidirectional, thus rendering the electron spins immune to decay due to momentum scattering. A robust persistent spin helix (PSH), i.e., a helical spin-density wave excitation with constant pitch P =2 π /Q , Q =4 m α /ℏ2, has already been experimentally realized at this singular point α =β , enhancing the spin lifetime by up to 2 orders of magnitude. Here, we employ the suppression of weak antilocalization as a sensitive detector for matched SO fields together with independent electrical control over the SO couplings via top gate voltage VT and back gate voltage VB to extract all SO couplings when combined with detailed numerical simulations. We demonstrate for the first time the gate control of the renormalized β and the continuous locking of the SO fields at α =β ; i.e., we are able to vary both α and β controllably and continuously with VT and VB, while keeping them locked at equal strengths. This makes possible a new concept: "stretchable PSHs," i.e., helical spin patterns with continuously variable pitches P over a wide parameter range. Stretching the PSH, i.e., gate controlling P while staying locked in the PSH regime, provides protection from spin decay at the symmetry point α =β , thus offering an important advantage over other methods. This protection is limited mainly by the cubic Dresselhaus term, which breaks the unidirectionality of the total SO field and causes spin decay at higher electron densities. We quantify the cubic term, and find it to be sufficiently weak so that

  16. Stretchable Persistent Spin Helices in GaAs Quantum Wells

    Directory of Open Access Journals (Sweden)

    Florian Dettwiler

    2017-07-01

    Full Text Available The Rashba and Dresselhaus spin-orbit (SO interactions in 2D electron gases act as effective magnetic fields with momentum-dependent directions, which cause spin decay as the spins undergo arbitrary precessions about these randomly oriented SO fields due to momentum scattering. Theoretically and experimentally, it has been established that by fine-tuning the Rashba α and renormalized Dresselhaus β couplings to equal fixed strengths α=β, the total SO field becomes unidirectional, thus rendering the electron spins immune to decay due to momentum scattering. A robust persistent spin helix (PSH, i.e., a helical spin-density wave excitation with constant pitch P=2π/Q, Q=4mα/ℏ^{2}, has already been experimentally realized at this singular point α=β, enhancing the spin lifetime by up to 2 orders of magnitude. Here, we employ the suppression of weak antilocalization as a sensitive detector for matched SO fields together with independent electrical control over the SO couplings via top gate voltage V_{T} and back gate voltage V_{B} to extract all SO couplings when combined with detailed numerical simulations. We demonstrate for the first time the gate control of the renormalized β and the continuous locking of the SO fields at α=β; i.e., we are able to vary both α and β controllably and continuously with V_{T} and V_{B}, while keeping them locked at equal strengths. This makes possible a new concept: “stretchable PSHs,” i.e., helical spin patterns with continuously variable pitches P over a wide parameter range. Stretching the PSH, i.e., gate controlling P while staying locked in the PSH regime, provides protection from spin decay at the symmetry point α=β, thus offering an important advantage over other methods. This protection is limited mainly by the cubic Dresselhaus term, which breaks the unidirectionality of the total SO field and causes spin decay at higher electron densities. We quantify the cubic term, and find it to be

  17. Point-by-point written fiber-Bragg gratings and their application in complex grating designs.

    Science.gov (United States)

    Marshall, Graham D; Williams, Robert J; Jovanovic, Nemanja; Steel, M J; Withford, Michael J

    2010-09-13

    The point-by-point technique of fabricating fibre-Bragg gratings using an ultrafast laser enables complete control of the position of each index modification that comprises the grating. By tailoring the local phase, amplitude and spacing of the grating's refractive index modulations it is possible to create gratings with complex transmission and reflection spectra. We report a series of grating structures that were realized by exploiting these flexibilities. Such structures include gratings with controlled bandwidth, and amplitude- and phase-modulated sampled (or superstructured) gratings. A model based on coupled-mode theory provides important insights into the manufacture of such gratings. Our approach offers a quick and easy method of producing complex, non-uniform grating structures in both fibres and other mono-mode waveguiding structures.

  18. Electrically Conductive TPU Nanofibrous Composite with High Stretchability for Flexible Strain Sensor

    Science.gov (United States)

    Tong, Lu; Wang, Xiao-Xiong; He, Xiao-Xiao; Nie, Guang-Di; Zhang, Jun; Zhang, Bin; Guo, Wen-Zhe; Long, Yun-Ze

    2018-03-01

    Highly stretchable and electrically conductive thermoplastic polyurethane (TPU) nanofibrous composite based on electrospinning for flexible strain sensor and stretchable conductor has been fabricated via in situ polymerization of polyaniline (PANI) on TPU nanofibrous membrane. The PANI/TPU membrane-based sensor could detect a strain from 0 to 160% with fast response and excellent stability. Meanwhile, the TPU composite has good stability and durability. Besides, the composite could be adapted to various non-flat working environments and could maintain opportune conductivity at different operating temperatures. This work provides an easy operating and low-cost method to fabricate highly stretchable and electrically conductive nanofibrous membrane, which could be applied to detect quick and tiny human actions.

  19. Tape transfer atomization patterning of liquid alloys for microfluidic stretchable wireless power transfer.

    Science.gov (United States)

    Jeong, Seung Hee; Hjort, Klas; Wu, Zhigang

    2015-02-12

    Stretchable electronics offers unsurpassed mechanical compliance on complex or soft surfaces like the human skin and organs. To fully exploit this great advantage, an autonomous system with a self-powered energy source has been sought for. Here, we present a new technology to pattern liquid alloys on soft substrates, targeting at fabrication of a hybrid-integrated power source in microfluidic stretchable electronics. By atomized spraying of a liquid alloy onto a soft surface with a tape transferred adhesive mask, a universal fabrication process is provided for high quality patterns of liquid conductors in a meter scale. With the developed multilayer fabrication technique, a microfluidic stretchable wireless power transfer device with an integrated LED was demonstrated, which could survive cycling between 0% and 25% strain over 1,000 times.

  20. Materials, Mechanics, and Patterning Techniques for Elastomer-Based Stretchable Conductors

    Directory of Open Access Journals (Sweden)

    Xiaowei Yu

    2016-12-01

    Full Text Available Stretchable electronics represent a new generation of electronics that utilize soft, deformable elastomers as the substrate or matrix instead of the traditional rigid printed circuit boards. As the most essential component of stretchable electronics, the conductors should meet the requirements for both high conductivity and the capability to maintain conductive under large deformations such as bending, twisting, stretching, and compressing. This review summarizes recent progresses in various aspects of this fascinating and challenging area, including materials for supporting elastomers and electrical conductors, unique designs and stretching mechanics, and the subtractive and additive patterning techniques. The applications are discussed along with functional devices based on these conductors. Finally, the review is concluded with the current limitations, challenges, and future directions of stretchable conductors.

  1. Effect of stiffness modulation on mechanical stability of stretchable a-IGZO TFTs

    Science.gov (United States)

    Park, Hyungjin; Cho, Kyoungah; Oh, Hyungon; Kim, Sangsig

    2018-05-01

    In this study, we fabricate the amorphous indium gallium zinc oxide (a-IGZO) thin-film transistors (TFTs) on a stretchable substrate with a buffer stage and investigate the mechanical stability and electrical characteristics when the length of the substrate is stretched by 1.7 times. The buffer stage is responsible for the stiffness modulation of the stretchable substrate. The mobility, the threshold voltage and the on/off ratio of the stretchable a-IGZO TFT are measured to be 18.1 cm2/V·s, 1 V, and 3 × 107, respectively. Our simulation conducted by a three dimensional finite elements method reveals that the stiffness modulation reduces the stress experienced by the substrate in the stretched state by about one-tenth. In addition, the mechanical stability and electrical characteristics of the a-IGZO TFT are maintained even when the substrate is stretched by 1.7 times.

  2. 2D reentrant auxetic structures of graphene/CNT networks for omnidirectionally stretchable supercapacitors.

    Science.gov (United States)

    Kim, Byoung Soo; Lee, Kangsuk; Kang, Seulki; Lee, Soyeon; Pyo, Jun Beom; Choi, In Suk; Char, Kookheon; Park, Jong Hyuk; Lee, Sang-Soo; Lee, Jonghwi; Son, Jeong Gon

    2017-09-14

    Stretchable energy storage systems are essential for the realization of implantable and epidermal electronics. However, high-performance stretchable supercapacitors have received less attention because currently available processing techniques and material structures are too limited to overcome the trade-off relationship among electrical conductivity, ion-accessible surface area, and stretchability of electrodes. Herein, we introduce novel 2D reentrant cellular structures of porous graphene/CNT networks for omnidirectionally stretchable supercapacitor electrodes. Reentrant structures, with inwardly protruded frameworks in porous networks, were fabricated by the radial compression of vertically aligned honeycomb-like rGO/CNT networks, which were prepared by a directional crystallization method. Unlike typical porous graphene structures, the reentrant structure provided structure-assisted stretchability, such as accordion and origami structures, to otherwise unstretchable materials. The 2D reentrant structures of graphene/CNT networks maintained excellent electrical conductivities under biaxial stretching conditions and showed a slightly negative or near-zero Poisson's ratio over a wide strain range because of their structural uniqueness. For practical applications, we fabricated all-solid-state supercapacitors based on 2D auxetic structures. A radial compression process up to 1/10 th densified the electrode, significantly increasing the areal and volumetric capacitances of the electrodes. Additionally, vertically aligned graphene/CNT networks provided a plentiful surface area and induced sufficient ion transport pathways for the electrodes. Therefore, they exhibited high gravimetric and areal capacitance values of 152.4 F g -1 and 2.9 F cm -2 , respectively, and had an excellent retention ratio of 88% under a biaxial strain of 100%. Auxetic cellular and vertically aligned structures provide a new strategy for the preparation of robust platforms for stretchable

  3. Rapid Prototyping Human Interfaces Using Stretchable Strain Sensor

    Directory of Open Access Journals (Sweden)

    Tokiya Yamaji

    2017-01-01

    Full Text Available In the modern society with a variety of information electronic devices, human interfaces increase their importance in a boundary of a human and a device. In general, the human is required to get used to the device. Even if the device is designed as a universal device or a high-usability device, the device is not suitable for all users. The usability of the device depends on the individual user. Therefore, personalized and customized human interfaces are effective for the user. To create customized interfaces, we propose rapid prototyping human interfaces using stretchable strain sensors. The human interfaces comprise parts formed by a three-dimensional printer and the four strain sensors. The three-dimensional printer easily makes customized human interfaces. The outputs of the interface are calculated based on the sensor’s lengths. Experiments evaluate three human interfaces: a sheet-shaped interface, a sliding lever interface, and a tilting lever interface. We confirm that the three human interfaces obtain input operations with a high accuracy.

  4. Stretchable GaAs photovoltaics with designs that enable high areal coverage

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Jongho; Yoon, Jongseung; Park, Sang-Il [Department of Materials Science and Engineering, Frederick Seitz Materials Research Laboratory, University of Illinois, Urbana-Champaign, IL (United States); Wu, Jian [Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL (United States); Shi, Mingxing; Liu, Zhuangjian [Institute of High Performance Computing, Singapore (Singapore); Li, Ming [Department of Civil and Environmental Engineering, Northwestern University, Evanston, IL (United States); Department of Engineering Mechanics, Dalian University of Technology, Dalian (China); Huang, Yonggang [Departments of Civil and Environmental Engineering and Mechanical Engineering, Northwestern University, Evanston, IL (United States); Rogers, John A. [Department of Materials Science and Engineering, Chemistry, Beckman Institute for Advanced Science and Technology, University of Illinois, Urbana-Champaign, IL (United States)

    2011-02-22

    Strategies are presented for achieving, simultaneously, both large areal coverage and high stretchability by using elastomeric substrates with surface relief in geometries that confine strains at the locations of the interconnections, and away from the devices. The studies involve a combination of theory and experiment to reveal the essential mechanics, and include demonstrations of the ideas in stretchable solar modules that use ultrathin, single junction GaAs solar cells. (Copyright copyright 2011 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  5. Biaxially stretchable supercapacitors based on the buckled hybrid fiber electrode array

    Science.gov (United States)

    Zhang, Nan; Zhou, Weiya; Zhang, Qiang; Luan, Pingshan; Cai, Le; Yang, Feng; Zhang, Xiao; Fan, Qingxia; Zhou, Wenbin; Xiao, Zhuojian; Gu, Xiaogang; Chen, Huiliang; Li, Kewei; Xiao, Shiqi; Wang, Yanchun; Liu, Huaping; Xie, Sishen

    2015-07-01

    In order to meet the growing need for smart bionic devices and epidermal electronic systems, biaxial stretchability is essential for energy storage units. Based on porous single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) hybrid fiber, we designed and fabricated a biaxially stretchable supercapacitor, which possesses a unique configuration of the parallel buckled hybrid fiber array. Owing to the reticulate SWCNT film and the improved fabrication technique, the hybrid fiber retained its porous architecture both outwardly and inwardly, manifesting a superior capacity of 215 F g-1. H3PO4-polyvinyl alcohol gel with an optimized component ratio was introduced as both binder and stretchable electrolyte, which contributed to the regularity and stability of the buckled fiber array. The buckled structure and the quasi one-dimensional character of the fibers endow the supercapacitor with 100% stretchability along all directions. In addition, the supercapacitor exhibited good transparency, as well as excellent electrochemical properties and stability after being stretched 5000 times.In order to meet the growing need for smart bionic devices and epidermal electronic systems, biaxial stretchability is essential for energy storage units. Based on porous single-walled carbon nanotube/poly(3,4-ethylenedioxythiophene) (SWCNT/PEDOT) hybrid fiber, we designed and fabricated a biaxially stretchable supercapacitor, which possesses a unique configuration of the parallel buckled hybrid fiber array. Owing to the reticulate SWCNT film and the improved fabrication technique, the hybrid fiber retained its porous architecture both outwardly and inwardly, manifesting a superior capacity of 215 F g-1. H3PO4-polyvinyl alcohol gel with an optimized component ratio was introduced as both binder and stretchable electrolyte, which contributed to the regularity and stability of the buckled fiber array. The buckled structure and the quasi one-dimensional character of the

  6. Feasibility evaluation of a neutron grating interferometer with an analyzer grating based on a structured scintillator

    Science.gov (United States)

    Kim, Youngju; Kim, Jongyul; Kim, Daeseung; Hussey, Daniel. S.; Lee, Seung Wook

    2018-03-01

    We introduce an analyzer grating based on a structured scintillator fabricated by a gadolinium oxysulfide powder filling method for a symmetric Talbot-Lau neutron grating interferometer. This is an alternative way to analyze the Talbot self-image of a grating interferometer without using an absorption grating to block neutrons. Since the structured scintillator analyzer grating itself generates the signal for neutron detection, we do not need an additional scintillator screen as an absorption analyzer grating. We have developed and tested an analyzer grating based on a structured scintillator in our symmetric Talbot-Lau neutron grating interferometer to produce high fidelity absorption, differential phase, and dark-field contrast images. The acquired images have been compared to results of a grating interferometer utilizing a typical absorption analyzer grating with two commercial scintillation screens. The analyzer grating based on the structured scintillator enhances interference fringe visibility and shows a great potential for economical fabrication, compact system design, and so on. We report the performance of the analyzer grating based on a structured scintillator and evaluate its feasibility for the neutron grating interferometer.

  7. Varied line-space gratings and applications

    International Nuclear Information System (INIS)

    McKinney, W.R.

    1991-01-01

    This paper presents a straightforward analytical and numerical method for the design of a specific type of varied line-space grating system. The mathematical development will assume plane or nearly-plane spherical gratings which are illuminated by convergent light, which covers many interesting cases for synchrotron radiation. The gratings discussed will have straight grooves whose spacing varies across the principal plane of the grating. Focal relationships and formulae for the optical grating-pole-to-exist-slit distance and grating radius previously presented by other authors will be derived with a symbolic algebra system. It is intended to provide the optical designer with the tools necessary to design such a system properly. Finally, some possible advantages and disadvantages for application to synchrotron to synchrotron radiation beamlines will be discussed

  8. EUV properties of two diffraction gratings

    International Nuclear Information System (INIS)

    Cotton, D.; Chakrabarti, S.; Edelstein, J.; Pranke, J.; Christensen, A.B.

    1988-01-01

    The efficiency and scattering characteristics of a mechanically ruled grating (MRG) and a holographically ruled grating (HRG) are presented. One of these gratings will be employed in the Extreme Ultraviolet Spectrometer, an instrument of the Remote Atmospheric and Ionospheric Detector System to be flown aboard a TIROS satellite in 1991. The HRG showed much less Lyman alpha scattering, while the MRG had the better efficiency over most of the spectral range covered. 8 refs

  9. Fibre gratings for high temperature sensor applications

    Science.gov (United States)

    Canning, J.; Sommer, K.; Englund, M.

    2001-07-01

    Phosphosilicate fibre gratings can be stabilized at temperatures in excess of 500 °C for sensor applications by optimizing thermal and UV presensitization recipes. Furthermore, the use of 193 nm presensitization prevents the formation of OH absorption bands, extending the use of fibre gratings across the entire wavelength spectrum. Gratings for operation at 700 °C retaining up to 70% reflectivity after 30 min are demonstrated.

  10. Stretchable Fiber Supercapacitors with High Volumetric Performance Based on Buckled MnO2 /Oxidized Carbon Nanotube Fiber Electrodes.

    Science.gov (United States)

    Li, Mingyang; Zu, Mei; Yu, Jinshan; Cheng, Haifeng; Li, Qingwen

    2017-03-01

    A stretchable fiber supercapacitor (SC) based on buckled MnO 2 /oxidized carbon nanotube (CNT) fiber electrode is fabricated by a simple prestraining-then-buckling method. The prepared stretchable fiber SC has a specific volumetric capacitance up to 409.4 F cm -3 , which is 33 times that of the pristine CNT fiber based SC, and shows the outstanding stability and repeatability in performance as a stretchable SC. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Reflectance spectra characteristics from an SPR grating fabricated by nano-imprint lithography technique for biochemical nanosensor applications

    Science.gov (United States)

    Setiya Pradana, Jalu; Hidayat, Rahmat

    2018-04-01

    In this paper, we report our research work on developing a Surface Plasmon Resonance (SPR) element with sub-micron (hundreds of nanometers) periodicity grating structure. This grating structure was fabricated by using a simple nano-imprint lithography technique from an organically siloxane polymers, which was then covered by nanometer thin gold layer. The formed grating structure was a very well defined square-shaped periodic structure. The measured reflectance spectra indicate the SPR wave excitation on this grating structure. For comparison, the simulations of reflectance spectra have been also carried out by using Rigorous Coupled-Wave Analysis (RCWA) method. The experimental results are in very good agreement with the simulation results.

  12. Tape transfer printing of a liquid metal alloy for stretchable RF electronics.

    Science.gov (United States)

    Jeong, Seung Hee; Hjort, Klas; Wu, Zhigang

    2014-09-03

    In order to make conductors with large cross sections for low impedance radio frequency (RF) electronics, while still retaining high stretchability, liquid-alloy-based microfluidic stretchable electronics offers stretchable electronic systems the unique opportunity to combine various sensors on our bodies or organs with high-quality wireless communication with the external world (devices/systems), without sacrificing enhanced user comfort. This microfluidic approach, based on printed circuit board technology, allows large area processing of large cross section conductors and robust contacts, which can handle a lot of stretching between the embedded rigid active components and the surrounding system. Although it provides such benefits, further development is needed to realize its potential as a high throughput, cost-effective process technology. In this paper, tape transfer printing is proposed to supply a rapid prototyping batch process at low cost, albeit at a low resolution of 150 μm. In particular, isolated patterns can be obtained in a simple one-step process. Finally, a stretchable radio frequency identification (RFID) tag is demonstrated. The measured results show the robustness of the hybrid integrated system when the tag is stretched at 50% for 3000 cycles.

  13. Electrical properties of AlGaN/GaN HEMTs in stretchable geometries

    Science.gov (United States)

    Tompkins, R. P.; Mahaboob, I.; Shahedipour-Sandvik, F.; Lazarus, N.

    2017-10-01

    Many biological materials are naturally soft and stretchable, far more so than crystalline semiconductors. Creating systems that can be placed directly on a surface such as human skin has required new approaches in electronic device design and materials, a field known as stretchable electronics. One common method for fabricating a highly brittle semiconductor device able to survive tens of percent strain is to incorporate stress relief structures ('waves'). Although the mechanical advantages of this approach are well known, the effects on the electrical behavior of a device such as a transistor compared to a more traditional geometry have not been studied. Here, AlGaN/GaN high electron mobility transistors (HEMTs) grown on rigid sapphire substrates were fabricated in a common wavy geometry, a sinusoid, with dimensions similar to those used in stretchable electronics. The study analyzes control parameters available to the designer including gate location along the sinusoid, angle the source-drain contacts make with the gate, as well as variation of the gate length at the peak of the sinusoid. Common electrical parameters such as saturation current density, threshold voltage, and transconductance were compared between the sinusoidal and conventional straight geometries and results found to fall to within experimental uncertainty, suggesting shifting to a stretchable geometry is possible without appreciably degrading semiconductor device performance.

  14. Tape Transfer Printing of a Liquid Metal Alloy for Stretchable RF Electronics

    Directory of Open Access Journals (Sweden)

    Seung Hee Jeong

    2014-09-01

    Full Text Available In order to make conductors with large cross sections for low impedance radio frequency (RF electronics, while still retaining high stretchability, liquid-alloy-based microfluidic stretchable electronics offers stretchable electronic systems the unique opportunity to combine various sensors on our bodies or organs with high-quality wireless communication with the external world (devices/systems, without sacrificing enhanced user comfort. This microfluidic approach, based on printed circuit board technology, allows large area processing of large cross section conductors and robust contacts, which can handle a lot of stretching between the embedded rigid active components and the surrounding system. Although it provides such benefits, further development is needed to realize its potential as a high throughput, cost-effective process technology. In this paper, tape transfer printing is proposed to supply a rapid prototyping batch process at low cost, albeit at a low resolution of 150 μm. In particular, isolated patterns can be obtained in a simple one-step process. Finally, a stretchable radio frequency identification (RFID tag is demonstrated. The measured results show the robustness of the hybrid integrated system when the tag is stretched at 50% for 3000 cycles.

  15. Highly Sensitive and Very Stretchable Strain Sensor Based on a Rubbery Semiconductor.

    Science.gov (United States)

    Kim, Hae-Jin; Thukral, Anish; Yu, Cunjiang

    2018-02-07

    There is a growing interest in developing stretchable strain sensors to quantify the large mechanical deformation and strain associated with the activities for a wide range of species, such as humans, machines, and robots. Here, we report a novel stretchable strain sensor entirely in a rubber format by using a solution-processed rubbery semiconductor as the sensing material to achieve high sensitivity, large mechanical strain tolerance, and hysteresis-less and highly linear responses. Specifically, the rubbery semiconductor exploits π-π stacked poly(3-hexylthiophene-2,5-diyl) nanofibrils (P3HT-NFs) percolated in silicone elastomer of poly(dimethylsiloxane) to yield semiconducting nanocomposite with a large mechanical stretchability, although P3HT is a well-known nonstretchable semiconductor. The fabricated strain sensors exhibit reliable and reversible sensing capability, high gauge factor (gauge factor = 32), high linearity (R 2 > 0.996), and low hysteresis (degree of hysteresis wearable smart gloves. Systematic investigations in the materials design and synthesis, sensor fabrication and characterization, and mechanical analysis reveal the key fundamental and application aspects of the highly sensitive and very stretchable strain sensors entirely from rubbers.

  16. Annealing effects on strain and stress sensitivity of polymer optical fibre based sensors

    DEFF Research Database (Denmark)

    Pospori, A.; Marques, C. A. F.; Zubel, M. G.

    2016-01-01

    The annealing effects on strain and stress sensitivity of polymer optical fibre Bragg grating sensors after their photoinscription are investigated. PMMA optical fibre based Bragg grating sensors are first photo-inscribed and then they were placed into hot water for annealing. Strain, stress...... fibre tends to increase the strain, stress and force sensitivity of the photo-inscribed sensor....

  17. Biosensing with optical fiber gratings

    Science.gov (United States)

    Chiavaioli, Francesco; Baldini, Francesco; Tombelli, Sara; Trono, Cosimo; Giannetti, Ambra

    2017-06-01

    Optical fiber gratings (OFGs), especially long-period gratings (LPGs) and etched or tilted fiber Bragg gratings (FBGs), are playing an increasing role in the chemical and biochemical sensing based on the measurement of a surface refractive index (RI) change through a label-free configuration. In these devices, the electric field evanescent wave at the fiber/surrounding medium interface changes its optical properties (i.e. intensity and wavelength) as a result of the RI variation due to the interaction between a biological recognition layer deposited over the fiber and the analyte under investigation. The use of OFG-based technology platforms takes the advantages of optical fiber peculiarities, which are hardly offered by the other sensing systems, such as compactness, lightness, high compatibility with optoelectronic devices (both sources and detectors), and multiplexing and remote measurement capability as the signal is spectrally modulated. During the last decade, the growing request in practical applications pushed the technology behind the OFG-based sensors over its limits by means of the deposition of thin film overlays, nanocoatings, and nanostructures, in general. Here, we review efforts toward utilizing these nanomaterials as coatings for high-performance and low-detection limit devices. Moreover, we review the recent development in OFG-based biosensing and identify some of the key challenges for practical applications. While high-performance metrics are starting to be achieved experimentally, there are still open questions pertaining to an effective and reliable detection of small molecules, possibly up to single molecule, sensing in vivo and multi-target detection using OFG-based technology platforms.

  18. Biosensing with optical fiber gratings

    Directory of Open Access Journals (Sweden)

    Chiavaioli Francesco

    2017-06-01

    Full Text Available Optical fiber gratings (OFGs, especially long-period gratings (LPGs and etched or tilted fiber Bragg gratings (FBGs, are playing an increasing role in the chemical and biochemical sensing based on the measurement of a surface refractive index (RI change through a label-free configuration. In these devices, the electric field evanescent wave at the fiber/surrounding medium interface changes its optical properties (i.e. intensity and wavelength as a result of the RI variation due to the interaction between a biological recognition layer deposited over the fiber and the analyte under investigation. The use of OFG-based technology platforms takes the advantages of optical fiber peculiarities, which are hardly offered by the other sensing systems, such as compactness, lightness, high compatibility with optoelectronic devices (both sources and detectors, and multiplexing and remote measurement capability as the signal is spectrally modulated. During the last decade, the growing request in practical applications pushed the technology behind the OFG-based sensors over its limits by means of the deposition of thin film overlays, nanocoatings, and nanostructures, in general. Here, we review efforts toward utilizing these nanomaterials as coatings for high-performance and low-detection limit devices. Moreover, we review the recent development in OFG-based biosensing and identify some of the key challenges for practical applications. While high-performance metrics are starting to be achieved experimentally, there are still open questions pertaining to an effective and reliable detection of small molecules, possibly up to single molecule, sensing in vivo and multi-target detection using OFG-based technology platforms.

  19. Running gratings in photoconductive materials

    DEFF Research Database (Denmark)

    Kukhtarev, N. V.; Kukhtareva, T.; Lyuksyutov, S. F.

    2005-01-01

    Starting from the three-dimensional version of a standard photorefractive model (STPM), we obtain a reduced compact Set of equations for an electric field based on the assumption of a quasi-steady-state fast recombination. The equations are suitable for evaluation of a current induced by running...... gratings at small-contrast approximation and also are applicable for the description of space-charge wave domains. We discuss spatial domain and subharmonic beam formation in bismuth silicon oxide (BSO) crystals in the framework of the small-contrast approximation of STPM. The experimental results...

  20. Polymer films

    Science.gov (United States)

    Granick, Steve; Sukhishvili, Svetlana A.

    2004-05-25

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

  1. Optical and diffractive properties of polymer: nanoparticles periodic structures obtained by holographic method

    Science.gov (United States)

    Smirnova, T. N.; Sakhno, O. V.; Goldberg, L.; Stumpe, J.

    2007-06-01

    The ordering of nanoparticles in polymer matrix using holographic photopolymerization is investigated. The general approach to the selection of the photopolymerizable compounds is proposed. The nonlinear and luminescent properties of obtained gratings are studied.

  2. 21 CFR 133.146 - Grated cheeses.

    Science.gov (United States)

    2010-04-01

    ... Products § 133.146 Grated cheeses. (a) Description. Grated cheeses is the class of foods prepared by..., and skim milk cheese for manufacturing may not be used. All cheese ingredients used are either made... ___ cheese”, the name of the cheese filling the blank. (ii) If only parmesan and romano cheeses are used and...

  3. The Flexibility of Pusher Furnace Grate

    Directory of Open Access Journals (Sweden)

    Słowik J.A.

    2016-12-01

    Full Text Available The lifetime of guide grates in pusher furnaces for heat treatment could be increased by raising the flexibility of their structure through, for example, the replacement of straight ribs, parallel to the direction of grate movement, with more flexible segments. The deformability of grates with flexible segments arranged in two orientations, i.e. crosswise (perpendicular to the direction of compression and lengthwise (parallel to the direction of compression, was examined. The compression process was simulated using SolidWorks Simulation program. Relevant regression equations were also derived describing the dependence of force inducing the grate deformation by 0.25 mm ‒ modulus of grate elasticity ‒ on the number of flexible segments in established orientations. These calculations were made in Statistica and Scilab programs. It has been demonstrated that, with the same number of segments, the crosswise orientation of flexible segments increases the grate structure flexibility in a more efficient way than the lengthwise orientation. It has also been proved that a crucial effect on the grate flexibility has only the quantity and orientation of segments (crosswise / lengthwise, while the exact position of segments changes the grate flexibility by less than 1%.

  4. Femtosecond laser pulse written Volume Bragg Gratings

    Directory of Open Access Journals (Sweden)

    Richter Daniel

    2013-11-01

    Full Text Available Femtosecond laser pulses can be applied for structuring a wide range of ransparent materials. Here we want to show how to use this ability to realize Volume-Bragg-Gratings in various- mainly non-photosensitive - glasses. We will further present the characteristics of the realized gratings and a few elected applications that have been realized.

  5. A MANUALLY OPERATED CASSAVA GRATING MACHINE

    African Journals Online (AJOL)

    Dr Obe

    1984-09-01

    Sep 1, 1984 ... substantial losses arising from the inability of the person to hold small pieces of cassava roots for grating. Happily, there now exist various. Versions of mechanical graters which are driven by electric motors or small internal combustion engines. In fact, it may be said that cassava grating has been effectively.

  6. A Flexible, Stretchable and Shape-Adaptive Approach for Versatile Energy Conversion and Self-Powered Biomedical Monitoring

    KAUST Repository

    Yang, Po Kang; Lin, Long; Yi, Fang; Li, Xiuhan; Pradel, Ken C.; Zi, Yunlong; Wu, Chih I.; He, Jr-Hau; Zhang, Yue; Wang, Zhong Lin

    2015-01-01

    A flexible triboelectric nanogenerator (FTENG) based on wavy-structured Kapton film and a serpentine electrode on stretchable substrates is presented. The as-fabricated FTENG is capable of harvesting ambient mechanical energy via both compressive

  7. The spectral combination characteristic of grating and the bi-grating diffraction imaging effect

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This paper reports on a new property of grating, namely spectral combination, and on bi-grating diffraction imaging that is based on spectral combination. The spectral combination characteristic of a grating is the capability of combining multiple light beams of different wavelengths incident from specific angles into a single beam. The bi-grating diffraction imaging is the formation of the image of an object with two gratings: the first grating disperses the multi-color light beams from the object and the second combines the dispersed light beams to form the image. We gave the conditions necessary for obtaining the spectral combination. We also presented the equations that relate the two gratings’ spatial frequencies, diffraction orders and positions necessary for obtaining the bi-grating diffraction imaging.

  8. Tunable meta-atom using liquid metal embedded in stretchable polymer

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Peng; Yang, Siming; Wang, Qiugu; Jiang, Huawei; Song, Jiming; Dong, Liang, E-mail: ldong@iastate.edu [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Jain, Aditya [Department of Electrical and Computer Engineering, Iowa State University, Ames, Iowa 50011 (United States); Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States); Koschny, Thomas; Soukoulis, Costas M. [Ames Laboratory, U.S. DOE and Department of Physics and Astronomy, Iowa State University, Ames, Iowa 50011 (United States)

    2015-07-07

    Reconfigurable metamaterials have great potential to alleviate complications involved in using passive metamaterials to realize emerging electromagnetic functions, such as dynamical filtering, sensing, and cloaking. This paper presents a new type of tunable meta-atoms in the X-band frequency range (8–12 GHz) toward reconfigurable metamaterials. The meta-atom is made of all flexible materials compliant to the surface of an interaction object. It uses a liquid metal-based split-ring resonator as its core constituent embedded in a highly flexible elastomer. We demonstrate that simple mechanical stretching of the meta-atom can lead to the great flexibility in reconfiguring its resonance frequency continuously over more than 70% of the X-band frequency range. The presented meta-atom technique provides a simple approach to dynamically tune response characteristics of metamaterials over a broad frequency range.

  9. Tunable meta-atom using liquid metal embedded in stretchable polymer

    International Nuclear Information System (INIS)

    Liu, Peng; Yang, Siming; Wang, Qiugu; Jiang, Huawei; Song, Jiming; Dong, Liang; Jain, Aditya; Koschny, Thomas; Soukoulis, Costas M.

    2015-01-01

    Reconfigurable metamaterials have great potential to alleviate complications involved in using passive metamaterials to realize emerging electromagnetic functions, such as dynamical filtering, sensing, and cloaking. This paper presents a new type of tunable meta-atoms in the X-band frequency range (8–12 GHz) toward reconfigurable metamaterials. The meta-atom is made of all flexible materials compliant to the surface of an interaction object. It uses a liquid metal-based split-ring resonator as its core constituent embedded in a highly flexible elastomer. We demonstrate that simple mechanical stretching of the meta-atom can lead to the great flexibility in reconfiguring its resonance frequency continuously over more than 70% of the X-band frequency range. The presented meta-atom technique provides a simple approach to dynamically tune response characteristics of metamaterials over a broad frequency range

  10. Polymeric flat focal field arrayed waveguide grating using electron-beam direct writing

    Science.gov (United States)

    Lu, Si; Yan, Yingbai; Jin, Guofan; Wong, W. H.; Pun, E. Y. B.

    2004-06-01

    A four-channel 400-GHz spacing flat focal field arrayed waveguide grating (AWG) demultiplexer is designed based on polymeric optical waveguide. The waveguide core-layer material is a newly developed negative tone epoxy Novolak resin (ENR) polymer with ultravoilet (UV) cured resin Norland optical adhesive 61 (NOA61) as the cladding layer. The device is fabricated using electron-beam direct writing, which has less processing steps than the reported polymeric AWGs. The experimental result is presented.

  11. Performance of the diffraction grating on a bank note: the experience with the Australian Commemorative note

    Science.gov (United States)

    Hardwick, Bruce A.

    1990-04-01

    In January 1988, we at the Note Printing Branch first released to the Reserve Bank a polymer based banknote containing an Optically Variable Device (OVD), a diffraction grating. This banknote was the culmination of many years of Research and Development effort, and represented a very significant departure from conventional banknote technology in many ways. It was a test bed. We are very pleased with its performance.

  12. Second harmonic generation and photochromic grating in polyurethane films containing diazo isoxazole chromophore

    Science.gov (United States)

    Marański, Krzysztof; Kucharski, Stanisław; Ortyl, Ewelina; Nunzi, Jean-Michel; Ahmadi-Kandjani, Sohrab; Dabos-Seignon, Sylvie; Chan, Siu-Wai; Barille, Regis

    2008-08-01

    The chromophoric intermediate: 2,2'-({4-[( E)-(5-methylisoxazol-3-yl)diazenyl]phenyl}-imino)diethanol was used in polyaddition reaction with di-isocyanate to obtain a new polyurethane polymeric material showing nonlinear optical and photochromic properties. The maximum absorption band of the polymer film was at 418 nm. The illumination of the film with crossed beams of the 488 nm Ar + laser yielded surface relief grating of regular structure. Measurement of the frequency doubling signal with 1064 nm laser indicated the polymer as interesting material for photooptical applications. The measured nonlinear optical coefficient, d33, reached 90.2 pm/V.

  13. Micro-Holograms in a Methyl Red-Doped Polymer-Dispersed Liquid Crystal (E48:PVP

    Directory of Open Access Journals (Sweden)

    N. P. Hermosa II

    2003-06-01

    Full Text Available Feasibility of a holographic point-by-point storage in a methyl red-doped Polymer-Dispersed LiquidCrystal (PDLC is determined. Micro-holograms (gratings are recorded next to each other. Smallestgrating diameter obtained is 69.9 mm, with minimum grating distance of 80 mm. Recording of adjacentgrating reduces the diffraction efficiency of existing grating by 17% (average.

  14. Fast and stable redox reactions of MnO2/CNT hybrid electrodes for dynamically stretchable pseudocapacitors

    Science.gov (United States)

    Gu, Taoli; Wei, Bingqing

    2015-07-01

    Pseudocapacitors, which are energy storage devices that take advantage of redox reactions to store electricity, have a different charge storage mechanism compared to lithium-ion batteries (LIBs) and electric double-layer capacitors (EDLCs), and they could realize further gains if they were used as stretchable power sources. The realization of dynamically stretchable pseudocapacitors and understanding of the underlying fundamentals of their mechanical-electrochemical relationship have become indispensable. We report herein the electrochemical performance of dynamically stretchable pseudocapacitors using buckled MnO2/CNT hybrid electrodes. The extremely small relaxation time constant of less than 0.15 s indicates a fast redox reaction at the MnO2/CNT hybrid electrodes, securing a stable electrochemical performance for the dynamically stretchable pseudocapacitors. This finding and the fundamental understanding gained from the pseudo-capacitive behavior coupled with mechanical deformation under a dynamic stretching mode would provide guidance to further improve their overall performance including a higher power density than LIBs, a higher energy density than EDLCs, and a long-life cycling stability. Most importantly, these results will potentially accelerate the applications of stretchable pseudocapacitors for flexible and biomedical electronics.Pseudocapacitors, which are energy storage devices that take advantage of redox reactions to store electricity, have a different charge storage mechanism compared to lithium-ion batteries (LIBs) and electric double-layer capacitors (EDLCs), and they could realize further gains if they were used as stretchable power sources. The realization of dynamically stretchable pseudocapacitors and understanding of the underlying fundamentals of their mechanical-electrochemical relationship have become indispensable. We report herein the electrochemical performance of dynamically stretchable pseudocapacitors using buckled MnO2/CNT hybrid

  15. Fiber Bragg Grating Sensors for Harsh Environments

    Directory of Open Access Journals (Sweden)

    Stephen J. Mihailov

    2012-02-01

    Full Text Available Because of their small size, passive nature, immunity to electromagnetic interference, and capability to directly measure physical parameters such as temperature and strain, fiber Bragg grating sensors have developed beyond a laboratory curiosity and are becoming a mainstream sensing technology. Recently, high temperature stable gratings based on regeneration techniques and femtosecond infrared laser processing have shown promise for use in extreme environments such as high temperature, pressure or ionizing radiation. Such gratings are ideally suited for energy production applications where there is a requirement for advanced energy system instrumentation and controls that are operable in harsh environments. This paper will present a review of some of the more recent developments.

  16. Optical Fiber Grating Hydrogen Sensors: A Review.

    Science.gov (United States)

    Dai, Jixiang; Zhu, Li; Wang, Gaopeng; Xiang, Feng; Qin, Yuhuan; Wang, Min; Yang, Minghong

    2017-03-12

    In terms of hydrogen sensing and detection, optical fiber hydrogen sensors have been a research issue due to their intrinsic safety and good anti-electromagnetic interference. Among these sensors, hydrogen sensors consisting of fiber grating coated with sensitive materials have attracted intensive research interests due to their good reliability and distributed measurements. This review paper mainly focuses on optical fiber hydrogen sensors associated with fiber gratings and various materials. Their configurations and sensing performances proposed by different groups worldwide are reviewed, compared and discussed in this paper. Meanwhile, the challenges for fiber grating hydrogen sensors are also addressed.

  17. Undergraduate experiment with fractal diffraction gratings

    International Nuclear Information System (INIS)

    Monsoriu, Juan A; Furlan, Walter D; Pons, Amparo; Barreiro, Juan C; Gimenez, Marcos H

    2011-01-01

    We present a simple diffraction experiment with fractal gratings based on the triadic Cantor set. Diffraction by fractals is proposed as a motivating strategy for students of optics in the potential applications of optical processing. Fraunhofer diffraction patterns are obtained using standard equipment present in most undergraduate physics laboratories and compared with those obtained with conventional periodic gratings. It is shown that fractal gratings produce self-similar diffraction patterns which can be evaluated analytically. Good agreement is obtained between experimental and numerical results.

  18. Nanoscale freestanding gratings for ultraviolet blocking filters

    Energy Technology Data Exchange (ETDEWEB)

    van Beek, J.T.; Fleming, R.C.; Hindle, P.S.; Prentiss, J.D.; Schattenburg, M.L. [Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Ritzau, S. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States)

    1998-11-01

    Ultraviolet (UV) blocking filters are needed for atomic flux imaging in environments where high levels of ultraviolet radiation are present. Freestanding gratings are a promising candidate for UV filtering. They have a high aspect ratio ({approximately}13), narrow ({approximately}40 nm) slots, and effectively block UV radiation. The grating fabrication process makes use of several etching, electroplating, and lithographic steps and includes an optional step to plug pinholes induced by particles during processing. Gratings were successfully manufactured and tested. Measured UV transmissions of {approximately}10{sup {minus}5} and particle transmissions of {approximately}10{percent} are in agreement with theoretical predictions. {copyright} {ital 1998 American Vacuum Society.}

  19. Sensitive visual test for concave diffraction gratings.

    Science.gov (United States)

    Bruner, E. C., Jr.

    1972-01-01

    A simple visual test for the evaluation of concave diffraction gratings is described. It is twice as sensitive as the Foucault knife edge test, from which it is derived, and has the advantage that the images are straight and free of astigmatism. It is particularly useful for grating with high ruling frequency where the above image faults limit the utility of the Foucault test. The test can be interpreted quantitatively and can detect zonal grating space errors of as little as 0.1 A.

  20. Thermal annealing of tilted fiber Bragg gratings

    Science.gov (United States)

    González-Vila, Á.; Rodríguez-Cobo, L.; Mégret, P.; Caucheteur, C.; López-Higuera, J. M.

    2016-05-01

    We report a practical study of the thermal decay of cladding mode resonances in tilted fiber Bragg gratings, establishing an analogy with the "power law" evolution previously observed on uniform gratings. We examine how this process contributes to a great thermal stability, even improving it by means of a second cycle slightly increasing the annealing temperature. In addition, we show an improvement of the grating spectrum after annealing, with respect to the one just after inscription, which suggests the application of this method to be employed to improve saturation issues during the photo-inscription process.

  1. Enhancing relative permittivity by incorporating PDMS-PEG multi block copolymers in binary polymer blends

    DEFF Research Database (Denmark)

    A Razak, Aliff Hisyam; Szabo, Peter; Skov, Anne Ladegaard

    Polydimethylsiloxanes (PDMS) are well-known to actuate with relatively large strains due to low modulus, but they possess lowpermittivity. Contrary, polyethyleneglycols (PEG) are not stretchable but possess high permittivity. Combination of the two polymers in a block copolymer depicts a possibil......Polydimethylsiloxanes (PDMS) are well-known to actuate with relatively large strains due to low modulus, but they possess lowpermittivity. Contrary, polyethyleneglycols (PEG) are not stretchable but possess high permittivity. Combination of the two polymers in a block copolymer depicts...... a possibility for substantial improvement of properties such as high permittivity, stretchability and non-conductivity – if carefully designed. The objective is to synthesize PDMS-PEG multiblock copolymer assembling into discontinuous morphologies in PEG based on variation of volume fractions of PDMS....... The utilized synthesis of PDMS-PEG multiblock copolymer is based on hydrosilylation reaction, which is amended from Klasner et al.1 and Jukarainen etal.2 Variation in the ratio between the two constituents introduces distinctive properties in terms of dielectric permittivity and rheological behaviour. PDMS...

  2. Geometrical optics modeling of the grating-slit test.

    Science.gov (United States)

    Liang, Chao-Wen; Sasian, Jose

    2007-02-19

    A novel optical testing method termed the grating-slit test is discussed. This test uses a grating and a slit, as in the Ronchi test, but the grating-slit test is different in that the grating is used as the incoherent illuminating object instead of the spatial filter. The slit is located at the plane of the image of a sinusoidal intensity grating. An insightful geometrical-optics model for the grating-slit test is presented and the fringe contrast ratio with respect to the slit width and object-grating period is obtained. The concept of spatial bucket integration is used to obtain the fringe contrast ratio.

  3. Fabrication update on critical-angle transmission gratings for soft x-ray grating spectrometers

    Science.gov (United States)

    Heilmann, Ralf K.; Bruccoleri, Alex; Mukherjee, Pran; Yam, Jonathan; Schattenburg, Mark L.

    2011-09-01

    Diffraction grating-based, wavelength dispersive high-resolution soft x-ray spectroscopy of celestial sources promises to reveal crucial data for the study of the Warm-Hot Intergalactic Medium, the Interstellar Medium, warm absorption and outflows in Active Galactic Nuclei, coronal emission from stars, and other areas of interest to the astrophysics community. Our recently developed critical-angle transmission (CAT) gratings combine the advantages of the Chandra high and medium energy transmission gratings (low mass, high tolerance of misalignments and figure errors, polarization insensitivity) with those of blazed reflection gratings (high broad band diffraction efficiency, high resolution through use of higher diffraction orders) such as the ones on XMM-Newton. Extensive instrument and system configuration studies have shown that a CAT grating-based spectrometer is an outstanding instrument capable of delivering resolving power on the order of 5,000 and high effective area, even with a telescope point-spread function on the order of many arc-seconds. We have fabricated freestanding, ultra-high aspect-ratio CAT grating bars from silicon-on-insulator wafers using both wet and dry etch processes. The 200 nm-period grating bars are supported by an integrated Level 1 support mesh, and a coarser external Level 2 support mesh. The resulting grating membrane is mounted to a frame, resulting in a grating facet. Many such facets comprise a grating array that provides light-weight coverage of large-area telescope apertures. Here we present fabrication results on the integration of CAT gratings and the different high-throughput support mesh levels and on membrane-frame bonding. We also summarize recent x-ray data analysis of 3 and 6 micron deep wet-etched CAT grating prototypes.

  4. Coaxial printing method for directly writing stretchable cable as strain sensor

    International Nuclear Information System (INIS)

    Yan, Hai-liang; Chen, Yan-qiu; Deng, Yong-qiang; Zhang, Li-long; Lau, Woon-ming; Mei, Jun; Liu, Yu; Hong, Xiao; Hui, David; Yan, Hui

    2016-01-01

    Through applying the liquid metal and elastomer as the core and shell materials, respectively, a coaxial printing method is being developed in this work for preparing a stretchable and conductive cable. When liquid metal alloy eutectic Gallium-Indium is embedded into the elastomer matrix under optimized control, the cable demonstrates well–posed extreme mechanic performance, under stretching for more than 350%. Under developed compression test, the fabricated cable also demonstrates the ability for recovering original properties due to the high flowability of the liquid metal and super elasticity of the elastomeric shell. The written cable presents high cycling reliability regarding its stretchability and conductivity, two properties which can be clearly predicted in theoretical calculation. This work can be further investigated as a strain sensor for monitoring motion status including frequency and amplitude of a curved object, with extensive applications in wearable devices, soft robots, electronic skins, and wireless communication.

  5. Flexible, Stretchable Sensors for Wearable Health Monitoring: Sensing Mechanisms, Materials, Fabrication Strategies and Features

    Science.gov (United States)

    Liu, Yan; Wang, Hai; Zhao, Wei; Qin, Hongbo; Xie, Yongqiang

    2018-01-01

    Wearable health monitoring systems have gained considerable interest in recent years owing to their tremendous promise for personal portable health watching and remote medical practices. The sensors with excellent flexibility and stretchability are crucial components that can provide health monitoring systems with the capability of continuously tracking physiological signals of human body without conspicuous uncomfortableness and invasiveness. The signals acquired by these sensors, such as body motion, heart rate, breath, skin temperature and metabolism parameter, are closely associated with personal health conditions. This review attempts to summarize the recent progress in flexible and stretchable sensors, concerning the detected health indicators, sensing mechanisms, functional materials, fabrication strategies, basic and desired features. The potential challenges and future perspectives of wearable health monitoring system are also briefly discussed. PMID:29470408

  6. Coaxial printing method for directly writing stretchable cable as strain sensor

    Energy Technology Data Exchange (ETDEWEB)

    Yan, Hai-liang [College of Material Science and Engineering, Beijing University of Technology, 100124 Beijing (China); Chengdu Green Energy and Green Manufacturing Technology R& D Center, 610299 Chengdu (China); Chen, Yan-qiu, E-mail: yu.liu@vip.163.com, E-mail: cyqleaf@qq.com, E-mail: hyan@but.ac.cn; Deng, Yong-qiang; Zhang, Li-long; Lau, Woon-ming; Mei, Jun; Liu, Yu, E-mail: yu.liu@vip.163.com, E-mail: cyqleaf@qq.com, E-mail: hyan@but.ac.cn [Chengdu Green Energy and Green Manufacturing Technology R& D Center, 610299 Chengdu (China); Hong, Xiao [Chengdu Green Energy and Green Manufacturing Technology R& D Center, 610299 Chengdu (China); College of Computer Science, Sichuan University, Chengdu 610207 (China); Hui, David [Department of Mechanical Engineering, University of New Orleans, New Orleans, Louisiana 70148 (United States); Yan, Hui, E-mail: yu.liu@vip.163.com, E-mail: cyqleaf@qq.com, E-mail: hyan@but.ac.cn [College of Material Science and Engineering, Beijing University of Technology, 100124 Beijing (China)

    2016-08-22

    Through applying the liquid metal and elastomer as the core and shell materials, respectively, a coaxial printing method is being developed in this work for preparing a stretchable and conductive cable. When liquid metal alloy eutectic Gallium-Indium is embedded into the elastomer matrix under optimized control, the cable demonstrates well–posed extreme mechanic performance, under stretching for more than 350%. Under developed compression test, the fabricated cable also demonstrates the ability for recovering original properties due to the high flowability of the liquid metal and super elasticity of the elastomeric shell. The written cable presents high cycling reliability regarding its stretchability and conductivity, two properties which can be clearly predicted in theoretical calculation. This work can be further investigated as a strain sensor for monitoring motion status including frequency and amplitude of a curved object, with extensive applications in wearable devices, soft robots, electronic skins, and wireless communication.

  7. Stretchable Kirigami Polyvinylidene Difluoride Thin Films for Energy Harvesting: Design, Analysis, and Performance

    Science.gov (United States)

    Hu, Nan; Chen, Dajing; Wang, Dong; Huang, Shicheng; Trase, Ian; Grover, Hannah M.; Yu, Xiaojiao; Zhang, John X. J.; Chen, Zi

    2018-02-01

    Kirigami, a modified form of origami which includes cutting, has been used to improve material stretchability and compliance. However, this technique is, so far, underexplored in patterning piezoelectric materials towards developing efficient and mechanically flexible thin-film energy generators. Motivated by existing kirigami-based applications, we introduce interdigitated cuts to polyvinylidene fluoride (PVDF) films to evaluate the effect on voltage generation and stretchability. Our results from theoretical analysis, numerical simulations, and experimental tests show that kirigami PVDF films exhibit an extended strain range while still maintaining significant voltage generation compared to films without cuts. Various cutting patterns are studied, and it is found that films with denser cuts have a larger voltage output. This kirigami design can enhance the properties of existing piezoelectric materials and help to integrate tunable PVDF generators into biomedical devices.

  8. Biodegradable elastomers and silicon nanomembranes/nanoribbons for stretchable, transient electronics, and biosensors.

    Science.gov (United States)

    Hwang, Suk-Won; Lee, Chi Hwan; Cheng, Huanyu; Jeong, Jae-Woong; Kang, Seung-Kyun; Kim, Jae-Hwan; Shin, Jiho; Yang, Jian; Liu, Zhuangjian; Ameer, Guillermo A; Huang, Yonggang; Rogers, John A

    2015-05-13

    Transient electronics represents an emerging class of technology that exploits materials and/or device constructs that are capable of physically disappearing or disintegrating in a controlled manner at programmed rates or times. Inorganic semiconductor nanomaterials such as silicon nanomembranes/nanoribbons provide attractive choices for active elements in transistors, diodes and other essential components of overall systems that dissolve completely by hydrolysis in biofluids or groundwater. We describe here materials, mechanics, and design layouts to achieve this type of technology in stretchable configurations with biodegradable elastomers for substrate/encapsulation layers. Experimental and theoretical results illuminate the mechanical properties under large strain deformation. Circuit characterization of complementary metal-oxide-semiconductor inverters and individual transistors under various levels of applied loads validates the design strategies. Examples of biosensors demonstrate possibilities for stretchable, transient devices in biomedical applications.

  9. Rugged and breathable forms of stretchable electronics with adherent composite substrates for transcutaneous monitoring

    Science.gov (United States)

    Jang, Kyung-In; Han, Sang Youn; Xu, Sheng; Mathewson, Kyle E.; Zhang, Yihui; Jeong, Jae-Woong; Kim, Gwang-Tae; Webb, R. Chad; Lee, Jung Woo; Dawidczyk, Thomas J.; Kim, Rak Hwan; Song, Young Min; Yeo, Woon-Hong; Kim, Stanley; Cheng, Huanyu; Rhee, Sang Il; Chung, Jeahoon; Kim, Byunggik; Chung, Ha Uk; Lee, Dongjun; Yang, Yiyuan; Cho, Moongee; Gaspar, John G.; Carbonari, Ronald; Fabiani, Monica; Gratton, Gabriele; Huang, Yonggang; Rogers, John A.

    2014-09-01

    Research in stretchable electronics involves fundamental scientific topics relevant to applications with importance in human healthcare. Despite significant progress in active components, routes to mechanically robust construction are lacking. Here, we introduce materials and composite designs for thin, breathable, soft electronics that can adhere strongly to the skin, with the ability to be applied and removed hundreds of times without damaging the devices or the skin, even in regions with substantial topography and coverage of hair. The approach combines thin, ultralow modulus, cellular silicone materials with elastic, strain-limiting fabrics, to yield a compliant but rugged platform for stretchable electronics. Theoretical and experimental studies highlight the mechanics of adhesion and elastic deformation. Demonstrations include cutaneous optical, electrical and radio frequency sensors for measuring hydration state, electrophysiological activity, pulse and cerebral oximetry. Multipoint monitoring of a subject in an advanced driving simulator provides a practical example.

  10. Micro-wrinkling and delamination-induced buckling of stretchable electronic structures

    International Nuclear Information System (INIS)

    Oyewole, O. K.; Yu, D.; Du, J.; Asare, J.; Fashina, A.; Oyewole, D. O.; Anye, V. C.; Zebaze Kana, M. G.

    2015-01-01

    This paper presents the results of experimental and theoretical/computational micro-wrinkles and buckling on the surfaces of stretchable poly-dimethylsiloxane (PDMS) coated with nano-scale Gold (Au) layers. The wrinkles and buckles are formed by the unloading of pre-stretched PDMS/Au structure after the evaporation of nano-scale Au layers. They are then characterized using atomic force microscopy and scanning electron microscopy. The critical stresses required for wrinkling and buckling are analyzed using analytical models. The possible interfacial cracking that can occur along with film buckling is also studied using finite element simulations of the interfacial crack growth. The implications of the results are discussed for potential applications of micro-wrinkles and micro-buckles in stretchable electronic structures and biomedical devices

  11. Rugged and breathable forms of stretchable electronics with adherent composite substrates for transcutaneous monitoring.

    Science.gov (United States)

    Jang, Kyung-In; Han, Sang Youn; Xu, Sheng; Mathewson, Kyle E; Zhang, Yihui; Jeong, Jae-Woong; Kim, Gwang-Tae; Webb, R Chad; Lee, Jung Woo; Dawidczyk, Thomas J; Kim, Rak Hwan; Song, Young Min; Yeo, Woon-Hong; Kim, Stanley; Cheng, Huanyu; Rhee, Sang Il; Chung, Jeahoon; Kim, Byunggik; Chung, Ha Uk; Lee, Dongjun; Yang, Yiyuan; Cho, Moongee; Gaspar, John G; Carbonari, Ronald; Fabiani, Monica; Gratton, Gabriele; Huang, Yonggang; Rogers, John A

    2014-09-03

    Research in stretchable electronics involves fundamental scientific topics relevant to applications with importance in human healthcare. Despite significant progress in active components, routes to mechanically robust construction are lacking. Here, we introduce materials and composite designs for thin, breathable, soft electronics that can adhere strongly to the skin, with the ability to be applied and removed hundreds of times without damaging the devices or the skin, even in regions with substantial topography and coverage of hair. The approach combines thin, ultralow modulus, cellular silicone materials with elastic, strain-limiting fabrics, to yield a compliant but rugged platform for stretchable electronics. Theoretical and experimental studies highlight the mechanics of adhesion and elastic deformation. Demonstrations include cutaneous optical, electrical and radio frequency sensors for measuring hydration state, electrophysiological activity, pulse and cerebral oximetry. Multipoint monitoring of a subject in an advanced driving simulator provides a practical example.

  12. Transparent and Stretchable High-Performance Supercapacitors Based on Wrinkled Graphene Electrodes

    Science.gov (United States)

    2013-12-18

    2, 870–875. 38. Chen, T.; Dai, L. Carbon Nanomaterials for High- Performance Supercapacitors . Mater. Today 2013, 16, 272–280. 39. Stoller, M. D...High-Performance Supercapacitors Based onWrinkledGraphene Electrodes Tao Chen,† Yuhua Xue,† Ajit K. Roy,‡ and Liming Dai†,* †Center of Advanced Science...electrodes and the associated supercapacitor cells cannot be both trans- parent and stretchable.1318 It is highly desirable to integrate the

  13. Stretchable Active Matrix Temperature Sensor Array of Polyaniline Nanofibers for Electronic Skin.

    Science.gov (United States)

    Hong, Soo Yeong; Lee, Yong Hui; Park, Heun; Jin, Sang Woo; Jeong, Yu Ra; Yun, Junyeong; You, Ilhwan; Zi, Goangseup; Ha, Jeong Sook

    2016-02-03

    A stretchable polyaniline nanofiber temperature sensor array with an active matrix consisting of single-walled carbon nanotube thin-film transistors is demonstrated. The integrated temperature sensor array gives mechanical stability under biaxial stretching of 30%, and the resultant spatial temperature mapping does not show any mechanical or electrical degradation. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Dielectric Actuation of Polymers

    Science.gov (United States)

    Niu, Xiaofan

    in tactile display is investigated by the prototyping of a large scale refreshable Braille display device. Braille is a critical way for the vision impaired community to learn literacy and improve life quality. Current piezoelectrics-based refreshable Braille display technologies are limited to up to 1 line of Braille text, due to the bulky size of bimorph actuators. Based on the unique actuation feature of BSEP, refreshable Braille display devices up to smartphone-size have been demonstrated by polymer sheet laminates. Dots in the devices can be individually controlled via incorporated field-driven BSEP actuators and Joule heater units. A composite material consisting of silver nanowires (AgNW) embedded in a polymer substrate is brought up as a compliant electrode candidate for BSEP application. The AgNW composite is highly conductive (Rs: 10 Ω/sq) and remains conductive at strains as high as 140% (Rs: <10 3 Ω/sq). The baseline conductivity has only small changes up to 90% strain, which makes it low enough for both field driving and stretchable Joule heating. An out-of-plane bistable area strain up to 68% under Joule heating is achieved.

  15. Access Platforms for Offshore Wind Turbines Using Gratings

    DEFF Research Database (Denmark)

    Andersen, Thomas Lykke; Rasmussen, Michael R.

    2008-01-01

    The paper deals with forces generated by a stationary jet on different types of gratings and a solid plate. The force reduction factors for the different gratings compared to the solid plate mainly depend on the porosity of the gratings, but the geometry of the grating is also of some importance........ The derived reduction factors are expected to be applicable to design of offshore wind turbine access platforms with gratings where slamming also is an important factor....

  16. Adaptable Diffraction Gratings With Wavefront Transformation

    Science.gov (United States)

    Iazikov, Dmitri; Mossberg, Thomas W.; Greiner, Christoph M.

    2010-01-01

    Diffraction gratings are optical components with regular patterns of grooves, which angularly disperse incoming light by wavelength. Traditional diffraction gratings have static planar, concave, or convex surfaces. However, if they could be made so that they can change the surface curvature at will, then they would be able to focus on particular segments, self-calibrate, or perform fine adjustments. This innovation creates a diffraction grating on a deformable surface. This surface could be bent at will, resulting in a dynamic wavefront transformation. This allows for self-calibration, compensation for aberrations, enhancing image resolution in a particular area, or performing multiple scans using different wavelengths. A dynamic grating gives scientists a new ability to explore wavefronts from a variety of viewpoints.

  17. Multiwavelength optical scatterometry of dielectric gratings

    KAUST Repository

    Yashina, Nataliya P.; Melezhik, Petr N.; Sirenko, Kostyantyn; Granet, Gerard

    2012-01-01

    is based on rigorous solutions of 2-D initial boundary value problems of the gratings theory. The quintessence and advantage of the method is the possibility to perform an efficient analysis simultaneously and interactively both for steady state

  18. Transparent and stretchable strain sensors based on metal nanowire microgrids for human motion monitoring

    Science.gov (United States)

    Cho, Ji Hwan; Ha, Sung-Hun; Kim, Jong-Man

    2018-04-01

    Optical transparency is increasingly considered as one of the most important characteristics required in advanced stretchable strain sensors for application in body-attachable systems. In this paper, we present an entirely solution-processed fabrication route to highly transparent and stretchable resistive strain sensors based on silver nanowire microgrids (AgNW-MGs). The AgNW-MG strain sensors are readily prepared by patterning the AgNWs on a stretchable substrate into a MG geometry via a mesh-template-assisted contact-transfer printing. The MG has a unique architecture comprising the AgNWs and can be stretched to ɛ = 35%, with high gauge factors of ˜6.9 for ɛ = 0%-30% and ˜41.1 for ɛ = 30%-35%. The sensor also shows a high optical transmittance of 77.1% ± 1.5% (at 550 nm) and stably maintains the remarkable optical performance even at high strains. In addition, the sensor responses are found to be highly reversible with negligible hysteresis and are reliable even under repetitive stretching-releasing cycles (1000 cycles at ɛ = 10%). The practicality of the AgNW-MG strain sensor is confirmed by successfully monitoring a wide range of human motions in real time after firmly laminating the device onto various body parts.

  19. Stretchable Tattoo-Like Heater with On-Site Temperature Feedback Control

    Directory of Open Access Journals (Sweden)

    Andrew Stier

    2018-04-01

    Full Text Available Wearable tissue heaters can play many important roles in the medical field. They may be used for heat therapy, perioperative warming and controlled transdermal drug delivery, among other applications. State-of-the-art heaters are too bulky, rigid, or difficult to control to be able to maintain long-term wearability and safety. Recently, there has been progress in the development of stretchable heaters that may be attached directly to the skin surface, but they often use expensive materials or processes and take significant time to fabricate. Moreover, they lack continuously active, on-site, unobstructive temperature feedback control, which is critical for accommodating the dynamic temperatures required for most medical applications. We have developed, fabricated and tested a cost-effective, large area, ultra-thin and ultra-soft tattoo-like heater that has autonomous proportional-integral-derivative (PID temperature control. The device comprises a stretchable aluminum heater and a stretchable gold resistance temperature detector (RTD on a soft medical tape as fabricated using the cost and time effective “cut-and-paste” method. It can be noninvasively laminated onto human skin and can follow skin deformation during flexure without imposing any constraint. We demonstrate the device’s ability to maintain a target temperature typical of medical uses over extended durations of time and to accurately adjust to a new set point in process. The cost of the device is low enough to justify disposable use.

  20. Stretchable carbon nanotube/ion-gel supercapacitors with high durability realized through interfacial microroughness.

    Science.gov (United States)

    Lee, Jiho; Kim, Wonbin; Kim, Woong

    2014-08-27

    A critical problem with stretchable supercapacitors developed to date has been evaporation of a volatile component of their electrolyte, causing failure. In this work, we demonstrated successful use of an ionic-liquid-based nonvolatile gel (ion-gel) electrolyte in carbon nanotube (CNT)-based stretchable supercapacitors. The CNT/ion-gel supercapacitors showed high capacitance retention (96.6%) over 3000 stretch cycles at 20% strain. The high durability against stretch cycles was achieved by introducing microroughness at the interfaces between different materials. The microroughness was produced by the simple process of imprinting the surface microstructure of office paper onto a poly(dimethylsiloxane) substrate; the surface texture is reproduced in successive current collector and CNT layers. Adhesion between the different layers was strengthened by this roughness and prevented delamination over repeated stretch cycles. The addition of a CNT layer decreased the sensitivity of electrical characteristics to stretching. Moreover, the ion-gel increases the operating voltage window (3 V) and hence the energy density. We believe our demonstration will greatly contribute to the development of flexible and/or stretchable energy-storage devices with high durability.

  1. A Stretchable Radio-Frequency Strain Sensor Using Screen Printing Technology.

    Science.gov (United States)

    Jeong, Heijun; Lim, Sungjoon

    2016-11-02

    In this paper, we propose a stretchable radio-frequency (RF) strain sensor fabricated with screen printing technology. The RF sensor is designed using a half-wavelength patch that resonates at 3.7 GHz. The resonant frequency is determined by the length of the patch, and it therefore changes when the patch is stretched. Polydimethylsiloxane (PDMS) is used to create the substrate, because of its stretchable and screen-printable surface. In addition, Dupont PE872 (Dupont, NC, American) silver conductive ink is used to create the stretchable conductive patterns. The sensor performance is demonstrated both with full-wave simulations and with measurements carried out on a fabricated sample. When the length of the patch sensor is increased by a 7.8% stretch, the resonant frequency decreases from 3.7 GHz to 3.43 GHz, evidencing a sensitivity of 3.43 × 10⁷ Hz/%. Stretching the patch along its width does not change the resonant frequency.

  2. CMOS-Technology-Enabled Flexible and Stretchable Electronics for Internet of Everything Applications

    KAUST Repository

    Hussain, Aftab M.

    2015-11-26

    Flexible and stretchable electronics can dramatically enhance the application of electronics for the emerging Internet of Everything applications where people, processes, data and devices will be integrated and connected, to augment quality of life. Using naturally flexible and stretchable polymeric substrates in combination with emerging organic and molecular materials, nanowires, nanoribbons, nanotubes, and 2D atomic crystal structured materials, significant progress has been made in the general area of such electronics. However, high volume manufacturing, reliability and performance per cost remain elusive goals for wide commercialization of these electronics. On the other hand, highly sophisticated but extremely reliable, batch-fabrication-capable and mature complementary metal oxide semiconductor (CMOS)-based technology has facilitated tremendous growth of today\\'s digital world using thin-film-based electronics; in particular, bulk monocrystalline silicon (100) which is used in most of the electronics existing today. However, one fundamental challenge is that state-of-the-art CMOS electronics are physically rigid and brittle. Therefore, in this work, how CMOS-technology-enabled flexible and stretchable electronics can be developed is discussed, with particular focus on bulk monocrystalline silicon (100). A comprehensive information base to realistically devise an integration strategy by rational design of materials, devices and processes for Internet of Everything electronics is offered. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Kirigami-based PVDF thin-film as stretchable strain sensor

    Science.gov (United States)

    Hu, Nan; Chen, Dajing; Hao, Nanjing; Huang, Shicheng; Yu, Xiaojiao; Zhang, John X. J.; Chen, Zi

    Kirigami, as the sister of the origami, involves cutting of 2D sheets to form complex 3D geometries with out-of-plane patterns. Motivated by the development of the high-stretchable biomedical devices, we explore the stretchability of the kirigami-based PVDF thin film under tension. Our structural prototypes include a set of 2D geometry with kirigami-based pattern cutting on PVDF thin films. We first used paper models to generate a wide range of cutting patterns to study the deformation under compression tests, the results of which are compared with finite element simulations. We then proceeded to test different kirigami-based designs to identify geometric parameters that can tune the post-buckling response and strain distribution. Next, we fabricated and tested the PVDF thin film with kirigami pattern. Experiments showed that the PVDF film in the absence of cutting can be stretched to a limited extent and will break upon further stretching. In contrast, the kirigami-based films can be stretched up to 100% without failure. Our designs demonstrate the ability to significantly improve the strain range of the structure and sensing ability of a sensor. We envision a promising future to use this class of structural elements to develop highly stretchable materials, structures, and devices. Z.C. acknowledges the Society in Science-Branco Weiss fellowship, administered by ETH Zürich. J.X.J.Z. acknowledges the NIH Director's Transformative Research Award (1R01 OD022910-01).

  4. Mechanically Robust, Stretchable Solar Absorbers with Submicron-Thick Multilayer Sheets for Wearable and Energy Applications.

    Science.gov (United States)

    Lee, Hye Jin; Jung, Dae-Han; Kil, Tae-Hyeon; Kim, Sang Hyeon; Lee, Ki-Suk; Baek, Seung-Hyub; Choi, Won Jun; Baik, Jeong Min

    2017-05-31

    A facile method to fabricate a mechanically robust, stretchable solar absorber for stretchable heat generation and an enhanced thermoelectric generator (TEG) is demonstrated. This strategy is very simple: it uses a multilayer film made of titanium and magnesium fluoride optimized by a two-dimensional finite element frequency-domain simulation, followed by the application of mechanical stresses such as bending and stretching to the film. This process produces many microsized sheets with submicron thickness (∼500 nm), showing great adhesion to any substrates such as fabrics and polydimethylsiloxane. It exhibits a quite high light absorption of approximately 85% over a wavelength range of 0.2-4.0 μm. Under 1 sun illumination, the solar absorber on various stretchable substrates increased the substrate temperature to approximately 60 °C, irrespective of various mechanical stresses such as bending, stretching, rubbing, and even washing. The TEG with the absorber on the top surface also showed an enhanced output power of 60%, compared with that without the absorber. With an incident solar radiation flux of 38.3 kW/m 2 , the output power significantly increased to 24 mW/cm 2 because of the increase in the surface temperature to 141 °C.

  5. Highly Stretchable and Transparent Microfluidic Strain Sensors for Monitoring Human Body Motions.

    Science.gov (United States)

    Yoon, Sun Geun; Koo, Hyung-Jun; Chang, Suk Tai

    2015-12-16

    We report a new class of simple microfluidic strain sensors with high stretchability, transparency, sensitivity, and long-term stability with no considerable hysteresis and a fast response to various deformations by combining the merits of microfluidic techniques and ionic liquids. The high optical transparency of the strain sensors was achieved by introducing refractive-index matched ionic liquids into microfluidic networks or channels embedded in an elastomeric matrix. The microfluidic strain sensors offer the outstanding sensor performance under a variety of deformations induced by stretching, bending, pressing, and twisting of the microfluidic strain sensors. The principle of our microfluidic strain sensor is explained by a theoretical model based on the elastic channel deformation. In order to demonstrate its capability of practical usage, the simple-structured microfluidic strain sensors were performed onto a finger, wrist, and arm. The highly stretchable and transparent microfluidic strain sensors were successfully applied as potential platforms for distinctively monitoring a wide range of human body motions in real time. Our novel microfluidic strain sensors show great promise for making future stretchable electronic devices.

  6. Fluoropolymer based composite with Ag particles as 3D printable conductive ink for stretchable electronics

    Science.gov (United States)

    Kumar, Amit; La, Thanh Giang; Li, Xinda; Chung, Hyun Joong

    The recent development of stretchable electronics expands the scope of wearable and healthcare applications. This creates a high demand in stretchy conductor that can maintain conductivity at high strain conditions. Here, we describe a simple fabrication pathway to achieve stretchable, 3D-printable and low-cost conductive composite ink. The ink is used to print complex stretchable patterns with high conductivity. The elastic ink is composed of silver(Ag) flakes, fluorine rubber, an organic solvent and surfactant. The surfactant plays multiple roles in in the composite. The surfactant promotes compatibility between silver flakes and fluorine rubber; at the same time, it affects the mechanical properties of the hosting fluoropolymers and adhesion properties of the composite. Based on experimental observations, we discuss the exact role of the surfactant in the composite. The resulting composite exhibits high conductivity value of 8.49 *10 4 S/m along with high reliability against repeated stretching/releasing cycles. Interesting examples of transfer printing of the printed ink and its applications in working devices, such as RFID tag and antennas, are also showcased.

  7. Deterministic Line-Shape Programming of Silicon Nanowires for Extremely Stretchable Springs and Electronics.

    Science.gov (United States)

    Xue, Zhaoguo; Sun, Mei; Dong, Taige; Tang, Zhiqiang; Zhao, Yaolong; Wang, Junzhuan; Wei, Xianlong; Yu, Linwei; Chen, Qing; Xu, Jun; Shi, Yi; Chen, Kunji; Roca I Cabarrocas, Pere

    2017-12-13

    Line-shape engineering is a key strategy to endow extra stretchability to 1D silicon nanowires (SiNWs) grown with self-assembly processes. We here demonstrate a deterministic line-shape programming of in-plane SiNWs into extremely stretchable springs or arbitrary 2D patterns with the aid of indium droplets that absorb amorphous Si precursor thin film to produce ultralong c-Si NWs along programmed step edges. A reliable and faithful single run growth of c-SiNWs over turning tracks with different local curvatures has been established, while high resolution transmission electron microscopy analysis reveals a high quality monolike crystallinity in the line-shaped engineered SiNW springs. Excitingly, in situ scanning electron microscopy stretching and current-voltage characterizations also demonstrate a superelastic and robust electric transport carried by the SiNW springs even under large stretching of more than 200%. We suggest that this highly reliable line-shape programming approach holds a strong promise to extend the mature c-Si technology into the development of a new generation of high performance biofriendly and stretchable electronics.

  8. Fibre Bragg grating for flood embankment monitoring

    Science.gov (United States)

    Markowski, Konrad; Nevar, Stanislau; Dworzanski, Adam; Hackiewicz, Krzysztof; Jedrzejewski, Kazimierz

    2014-11-01

    In this article we present the preliminary studies for the flood embankment monitoring system based on the fibre Bragg gratings. The idea of the system is presented. The Bragg resonance shift is transformed to the change of the power detected by the standard InGaAs photodiode. The discrimination of the received power was executed by another fibre Bragg grating with different parameters. The project of the fully functional system is presented as well.

  9. Grism and immersion grating for space telescope

    Science.gov (United States)

    Ebizuka, Noboru; Oka, Kiko; Yamada, Akiko; Ishikawa, Mami; Kashiwagi, Masako; Kodate, Kashiko; Hirahara, Yasuhiro; Sato, Shuji; Kawabata, Koji S.; Wakaki, Moriaki; Morita, Shin-ya; Simizu, Tomoyuki; Yin, Shaohui; Omori, Hitoshi; Iye, Masanori

    2017-11-01

    The grism is a versatile dispersion element for an astronomical instrument ranging from ultraviolet to infrared. Major benefit of using a grism in a space application, instead of a reflection grating, is the size reduction of optical system because collimator and following optical elements could locate near by the grism. The surface relief (SR) grism is consisted a transmission grating and a prism, vertex angle of which is adjusted to redirect the diffracted beam straight along the direct vision direction at a specific order and wavelength. The volume phase holographic (VPH) grism consists a thick VPH grating sandwiched between two prisms, as specific order and wavelength is aligned the direct vision direction. The VPH grating inheres ideal diffraction efficiency on a higher dispersion application. On the other hand, the SR grating could achieve high diffraction efficiency on a lower dispersion application. Five grisms among eleven for the Faint Object Camera And Spectrograph (FOCAS) of the 8.2m Subaru Telescope with the resolving power from 250 to 3,000 are SR grisms fabricated by a replication method. Six additional grisms of FOCAS with the resolving power from 3,000 to 7,000 are VPH grisms. We propose "Quasi-Bragg grism" for a high dispersion spectroscopy with wide wavelength range. The germanium immersion grating for instance could reduce 1/64 as the total volume of a spectrograph with a conventional reflection grating since refractive index of germanium is over 4.0 from 1.6 to 20 μm. The prototype immersion gratings for the mid-InfraRed High dispersion Spectrograph (IRHS) are successfully fabricated by a nano-precision machine and grinding cup of cast iron with electrolytic dressing method.

  10. Multiplexing storage using angular variation in a transmission holographic polymer dispersed liquid crystal

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Eun-Hee; Jung, Yeon-Gil, E-mail: jungyg@changwon.ac.kr

    2015-12-01

    Simultaneous angular multiplexing of transmission gratings in a holographic polymer dispersed liquid crystal (HPDLC) film as a function of resin and film compositions, irradiation intensity, and cell thickness has been studied by exposing the material to three coherent laser beams. It was found that the diffraction efficiency monotonically increases with irradiation intensity and cell gap, whereas a maximum of 43% is obtained at specific compositions of trimethylolpropane triacrylate (TMPTA)/N-vinylpyrrolidone (NVP) = 8/1 and polymer/LC = 65/35. The multiplexed gratings have been captured using SEM imaging and the reconstructed images using a charge-coupled device camera, showing successful reconstructed images of gratings. - Highlights: • Multiplex images were well recorded using simultaneous angular method. • The periodic structures of the LC and polymer regions were well prepared. • The angular selectivity was variable nevertheless fabrication by three beams. • The images were successfully reconstructed in gratings of same spot.

  11. Multiplexing storage using angular variation in a transmission holographic polymer dispersed liquid crystal

    International Nuclear Information System (INIS)

    Kim, Eun-Hee; Jung, Yeon-Gil

    2015-01-01

    Simultaneous angular multiplexing of transmission gratings in a holographic polymer dispersed liquid crystal (HPDLC) film as a function of resin and film compositions, irradiation intensity, and cell thickness has been studied by exposing the material to three coherent laser beams. It was found that the diffraction efficiency monotonically increases with irradiation intensity and cell gap, whereas a maximum of 43% is obtained at specific compositions of trimethylolpropane triacrylate (TMPTA)/N-vinylpyrrolidone (NVP) = 8/1 and polymer/LC = 65/35. The multiplexed gratings have been captured using SEM imaging and the reconstructed images using a charge-coupled device camera, showing successful reconstructed images of gratings. - Highlights: • Multiplex images were well recorded using simultaneous angular method. • The periodic structures of the LC and polymer regions were well prepared. • The angular selectivity was variable nevertheless fabrication by three beams. • The images were successfully reconstructed in gratings of same spot.

  12. Biodegradable Polymers

    OpenAIRE

    Vroman, Isabelle; Tighzert, Lan

    2009-01-01

    Biodegradable materials are used in packaging, agriculture, medicine and other areas. In recent years there has been an increase in interest in biodegradable polymers. Two classes of biodegradable polymers can be distinguished: synthetic or natural polymers. There are polymers produced from feedstocks derived either from petroleum resources (non renewable resources) or from biological resources (renewable resources). In general natural polymers offer fewer advantages than synthetic polymers. ...

  13. Dynamic optical coupled system employing Dammann gratings

    Science.gov (United States)

    Di, Caihui; Zhou, Changhe; Ru, Huayi

    2004-10-01

    With the increasing of the number of users in optical fiber communications, fiber-to-home project has a larger market value. Then the need of dynamic optical couplers, especially of N broad-band couplers, becomes greater. Though some advanced fiber fusion techniques have been developed, they still have many shortcomings. In this paper we propose a dynamic optical coupled system employing even-numbered Dammann gratings, which have the characteristic that the phase distribution in the first half-period accurately equals to that in the second-period with π phase inversion. In our experiment, we divide a conventional even-numbered Dammann grating into two identical gratings. The system can achieve the beam splitter and combiner as the switch between them according to the relative shift between two complementary gratings. When there is no shift between the gratings, the demonstrated 1×8 dynamic optical coupler achieves good uniformity of 0.06 and insertion loss of around 10.8 dB for each channel as a splitter. When the two gratings have an accurate shift of a half-period between them, our system has a low insertion loss of 0.46 dB as a combiner at a wavelength of 1550 nm.

  14. Theoretical modeling and design of photonic structures in zeolite nanocomposites for gas sensing. Part I: surface relief gratings.

    Science.gov (United States)

    Cody, D; Naydenova, I

    2017-12-01

    The suitability of holographic structures fabricated in zeolite nanoparticle-polymer composite materials for gas sensing applications has been investigated. Theoretical modeling of the sensor response (i.e., change in hologram readout due to a change in refractive index modulation or thickness as a result of gas adsorption) of different sensor designs was carried out using Raman-Nath theory and Kogelnik's coupled wave theory. The influence of a range of parameters on the sensor response of holographically recorded surface and volume photonic grating structures has been studied, namely the phase difference between the diffracted and probe beam introduced by the grating, grating geometry, thickness, spatial frequency, reconstruction wavelength, and zeolite nanoparticle refractive index. From this, the optimum fabrication conditions for both surface and volume holographic gas sensor designs have been identified. Here, in part I, results from theoretical modeling of the influence of design on the sensor response of holographically inscribed surface relief structures for gas sensing applications is reported.

  15. Polymer compound

    NARCIS (Netherlands)

    1995-01-01

    A Polymer compound comprising a polymer (a) that contains cyclic imidesgroups and a polymer (b) that contains monomer groups with a 2,4-diamino-1,3,5-triazine side group. According to the formula (see formula) whereby themole percentage ratio of the cyclic imides groups in the polymer compoundwith

  16. Single-mode solid-state polymer dye laser fabricated with standard I-line UV lithography

    DEFF Research Database (Denmark)

    Balslev, Søren; Mironov, Andrej; Nilsson, Daniel

    2005-01-01

    We present single-mode solid-state polymer dye lasers fabricated with standard UV lithography. The lasers use a high-order Bragg grating and rely on index-tuning of a photosensitive polymer for waveguiding. The gain medium is Rhodamine 6G.......We present single-mode solid-state polymer dye lasers fabricated with standard UV lithography. The lasers use a high-order Bragg grating and rely on index-tuning of a photosensitive polymer for waveguiding. The gain medium is Rhodamine 6G....

  17. Simple design of slanted grating with simplified modal method.

    Science.gov (United States)

    Li, Shubin; Zhou, Changhe; Cao, Hongchao; Wu, Jun

    2014-02-15

    A simplified modal method (SMM) is presented that offers a clear physical image for subwavelength slanted grating. The diffraction characteristic of the slanted grating under Littrow configuration is revealed by the SMM as an equivalent rectangular grating, which is in good agreement with rigorous coupled-wave analysis. Based on the equivalence, we obtained an effective analytic solution for simplifying the design and optimization of a slanted grating. It offers a new approach for design of the slanted grating, e.g., a 1×2 beam splitter can be easily designed. This method should be helpful for designing various new slanted grating devices.

  18. Perturbative approach to continuum generation in a fiber Bragg grating.

    Science.gov (United States)

    Westbrook, P S; Nicholson, J W

    2006-08-21

    We derive a perturbative solution to the nonlinear Schrödinger equation to include the effect of a fiber Bragg grating whose bandgap is much smaller than the pulse bandwidth. The grating generates a slow dispersive wave which may be computed from an integral over the unperturbed solution if nonlinear interaction between the grating and unperturbed waves is negligible. Our approach allows rapid estimation of large grating continuum enhancement peaks from a single nonlinear simulation of the waveguide without grating. We apply our method to uniform and sampled gratings, finding good agreement with full nonlinear simulations, and qualitatively reproducing experimental results.

  19. Polymer electronics

    CERN Document Server

    Hsin-Fei, Meng

    2013-01-01

    Polymer semiconductor is the only semiconductor that can be processed in solution. Electronics made by these flexible materials have many advantages such as large-area solution process, low cost, and high performance. Researchers and companies are increasingly dedicating time and money in polymer electronics. This book focuses on the fundamental materials and device physics of polymer electronics. It describes polymer light-emitting diodes, polymer field-effect transistors, organic vertical transistors, polymer solar cells, and many applications based on polymer electronics. The book also disc

  20. Optical pulse multiplication and temporal coding using true time delay achieved by long-period fiber gratings in dispersion compensating fiber.

    Science.gov (United States)

    Eom, Tae Joong; Kim, Sun-Jong; Kim, Tae-Young; Park, Chang-Soo; Lee, Byeong

    2004-12-27

    We present an optical pulse multiplication and a temporal coding method for OCDMA systems. The true time delay among the pulses was obtained by utilizing the difference in the propagation speeds of the core and the co-propagating cladding modes coupled by long-period fiber gratings. By cascadin gratings we could get an equally spaced 40 GHz pulse train from a 10 GHz train. Various coding and decoding of a pulse train were possible by controlling the separations among the gratings. The dispersion compensating fiber having an inner cladding structure enabled to have the gratings that were not sensitive to the polymer jacket of the fiber and allowed shortening the device length.

  1. Laser-engraved carbon nanotube paper for instilling high sensitivity, high stretchability, and high linearity in strain sensors

    KAUST Repository

    Xin, Yangyang

    2017-06-29

    There is an increasing demand for strain sensors with high sensitivity and high stretchability for new applications such as robotics or wearable electronics. However, for the available technologies, the sensitivity of the sensors varies widely. These sensors are also highly nonlinear, making reliable measurement challenging. Here we introduce a new family of sensors composed of a laser-engraved carbon nanotube paper embedded in an elastomer. A roll-to-roll pressing of these sensors activates a pre-defined fragmentation process, which results in a well-controlled, fragmented microstructure. Such sensors are reproducible and durable and can attain ultrahigh sensitivity and high stretchability (with a gauge factor of over 4.2 × 10(4) at 150% strain). Moreover, they can attain high linearity from 0% to 15% and from 22% to 150% strain. They are good candidates for stretchable electronic applications that require high sensitivity and linearity at large strains.

  2. Iridescence in Meat Caused by Surface Gratings

    Directory of Open Access Journals (Sweden)

    Ali Kemal Yetisen

    2013-11-01

    Full Text Available The photonic structure of cut muscle tissues reveals that the well-ordered gratings diffract light, producing iridescent colours. Cut fibrils protruding from the muscle surface create a two-dimensional periodic array, which diffract light at specific wavelengths upon illumination. However, this photonic effect misleads consumers in a negative way to relate the optical phenomenon with the quality of the product. Here we discuss the fundamentals of this optical phenomenon and demonstrate a methodology for quantitatively measuring iridescence caused by diffraction gratings of muscle tissue surface of pork (Sus scrofa domesticus using reflection spectrophotometry. Iridescence was discussed theoretically as a light phenomenon and spectral measurements were taken from the gratings and monitored in real time during controlled drying. The findings show that the intensity of diffraction diminishes as the surface grating was dried with an air flow at 50 °C for 2 min while the diffracted light wavelength was at 585 ± 9 nm. Our findings indicate that the diffraction may be caused by a blazed surface grating. The implications of the study include providing guidelines to minimise the iridescence by altering the surface microstructure, and in consequence, removing the optical effect.

  3. 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)

  4. Grating array systems having a plurality of gratings operative in a coherently additive mode and methods for making such grating array systems

    Science.gov (United States)

    Kessler, Terrance J [Mendon, NY; Bunkenburg, Joachim [Victor, NY; Huang, Hu [Pittsford, NY

    2007-02-13

    A plurality of gratings (G1, G2) are arranged together with a wavefront sensor, actuators, and feedback system to align the gratings in such a manner, that they operate like a single, large, monolithic grating. Sub-wavelength-scale movements in the mechanical mounting, due to environmental influences, are monitored by an interferometer (28), and compensated by precision actuators (16, 18, 20) that maintain the coherently additive mode. The actuators define the grating plane, and are positioned in response to the wavefronts from the gratings and a reference flat, thus producing the interferogram that contains the alignment information. Movement of the actuators is also in response to a diffraction-limited spot on the CCD (36) to which light diffracted from the gratings is focused. The actuator geometry is implemented to take advantage of the compensating nature of the degrees of freedom between gratings, reducing the number of necessary control variables.

  5. Design and analysis of dual-resonant filters in visible and infra-red region based on polymer LPWG

    Science.gov (United States)

    Sharma, Mukesh; Kushwaha, Aniruddha Singh; Pal, Suchandan

    2013-01-01

    Long-period waveguide gratings (LPWGs), by using a SU-8 polymer-based channel waveguide along with NOA61 optical epoxy coated upper- and lower-cladding, are designed and theoretical analyzed. Grating period of ~ 68μm is considered with optimized grating tooth-heights, so that the transmission spectra of the gratings show strong rejection bands both at visible (450 - 460 nm) and infrared (1530 - 1540 nm) wavelength regions. Phase-matching graphs are studied in order to observe the change in resonance wavelength of the grating with the variation of waveguide parameters. LPWG-based band pass filter are also designed and analyzed by considering the same set of polymer materials. Further, temperature sensitivity of these LPWGs is analyzed theoretically. These types of waveguide gratingbased filters can widely be used for visible and infrared wavelength sensing applications.

  6. Diffraction by m-bonacci gratings

    International Nuclear Information System (INIS)

    Monsoriu, Juan A; Giménez, Marcos H; Furlan, Walter D; Barreiro, Juan C; Saavedra, Genaro

    2015-01-01

    We present a simple diffraction experiment with m-bonacci gratings as a new interesting generalization of the Fibonacci ones. Diffraction by these non-conventional structures is proposed as a motivational strategy to introduce students to basic research activities. The Fraunhofer diffraction patterns are obtained with the standard equipment present in most undergraduate physics labs and are compared with those obtained with regular periodic gratings. We show that m-bonacci gratings produce discrete Fraunhofer patterns characterized by a set of diffraction peaks which positions are related to the concept of a generalized golden mean. A very good agreement is obtained between experimental and numerical results and the students’ feedback is discussed. (paper)

  7. An ultra-high-vacuum multiple grating chamber and scan drive with improved grating change

    International Nuclear Information System (INIS)

    Hulbert, S.L.; Holly, D.J.; Middleton, F.H.; Wallace, D.J.; Wisconsin Univ., Stoughton, WI; Wisconsin Univ., Stoughton, WI

    1989-01-01

    We describe a new grating chamber and scan drive which has been designed, built, and tested by Physical Sciences Laboratory of the University of Wisconsin for the new high flux, high-resolution spectroscopy branch line of the TOK hybrid wiggler/undulator on the NSLS VUV ring. The chamber will contain spherical gratings to be used in the Spherical Grating Monochromator (SGM) configuration introduced by Chen and Sette. The grating chamber houses five 180 mm x 35 mm x 30 mm gratings capable of scanning a range of 12 degree (-14 degree to +8 degree with respect to the incoming beam direction) for VUV and soft X-ray diffraction. The gratings can be switched and precisely indexed while under ultra-high vacuum (UHV) at any scan angle and are mechanically isolated from the vacuum chamber to prevent inaccuracies due to chamber distortions. The gratings can separately be adjusted for height, yaw, pitch, and roll, with the latter three performed while in vacuo. The scan drive provides a resolution of 0.03 arc sec with linearity over the 12 degree range of ∼1.5 arc sec and absolute reproducibility of 1 arc sec. 5 refs., 5 figs

  8. Vacuum Predisperser For A Large Plane-Grating Spectrograph

    Science.gov (United States)

    Engleman, R.; Palmer, B. A.; Steinhaus, D. W.

    1980-11-01

    A plane grating predisperser has been constructed which acts as an "order-sorter" for a large plane-grating spectrograph. This combination can photograph relatively wide regions of spectra in a single exposure with no loss of resolution.

  9. Multiwavelength optical scatterometry of dielectric gratings

    KAUST Repository

    Yashina, Nataliya P.

    2012-08-01

    Modern scatterometry problems arising in the lithography production of periodic gratings are in the focus of the work. The performance capabilities of a novel theoretical and numerical modeling oriented to these problems are considered. The approach is based on rigorous solutions of 2-D initial boundary value problems of the gratings theory. The quintessence and advantage of the method is the possibility to perform an efficient analysis simultaneously and interactively both for steady state and transient processes of the resonant scattering of electromagnetic waves by the infinite and compact periodic structures. © 2012 IEEE.

  10. Stretchable Transparent Electrode Arrays for Simultaneous Electrical and Optical Interrogation of Neural Circuits in Vivo.

    Science.gov (United States)

    Zhang, Jing; Liu, Xiaojun; Xu, Wenjing; Luo, Wenhan; Li, Ming; Chu, Fangbing; Xu, Lu; Cao, Anyuan; Guan, Jisong; Tang, Shiming; Duan, Xiaojie

    2018-04-09

    Recent developments of transparent electrode arrays provide a unique capability for simultaneous optical and electrical interrogation of neural circuits in the brain. However, none of these electrode arrays possess the stretchability highly desired for interfacing with mechanically active neural systems, such as the brain under injury, the spinal cord, and the peripheral nervous system (PNS). Here, we report a stretchable transparent electrode array from carbon nanotube (CNT) web-like thin films that retains excellent electrochemical performance and broad-band optical transparency under stretching and is highly durable under cyclic stretching deformation. We show that the CNT electrodes record well-defined neuronal response signals with negligible light-induced artifacts from cortical surfaces under optogenetic stimulation. Simultaneous two-photon calcium imaging through the transparent CNT electrodes from cortical surfaces of GCaMP-expressing mice with epilepsy shows individual activated neurons in brain regions from which the concurrent electrical recording is taken, thus providing complementary cellular information in addition to the high-temporal-resolution electrical recording. Notably, the studies on rats show that the CNT electrodes remain operational during and after brain contusion that involves the rapid deformation of both the electrode array and brain tissue. This enables real-time, continuous electrophysiological monitoring of cortical activity under traumatic brain injury. These results highlight the potential application of the stretchable transparent CNT electrode arrays in combining electrical and optical modalities to study neural circuits, especially under mechanically active conditions, which could potentially provide important new insights into the local circuit dynamics of the spinal cord and PNS as well as the mechanism underlying traumatic injuries of the nervous system.

  11. Nanogap embedded silver gratings for surface plasmon enhanced fluorescence

    Science.gov (United States)

    Bhatnagar, Kunal

    Plasmonic nanostructures have been extensively used in the past few decades for applications in sub-wavelength optics, data storage, optoelectronic circuits, microscopy and bio-photonics. The enhanced electromagnetic field produced at the metal and dielectric interface by the excitation of surface plasmons via incident radiation can be used for signal enhancement in fluorescence and surface enhanced Raman scattering studies. Novel plasmonic structures have shown to provide very efficient and extreme light concentration at the nano-scale in recent years. The enhanced electric field produced within a few hundred nanometers of these surfaces can be used to excite fluorophores in the surrounding environment. Fluorescence based bio-detection and bio-imaging are two of the most important tools in the life sciences and improving the qualities and capabilities of fluorescence based detectors and imaging equipment remains a big challenge for industry manufacturers. We report a novel fabrication technique for producing nano-gap embedded periodic grating substrates on the nanoscale using a store bought HD-DVD and conventional soft lithography procedures. Polymethylsilsesquioxane (PMSSQ) polymer is used as the ink for the micro-contact printing process with PDMS stamps obtained from the inexpensive HD-DVDs as master molds. Fluorescence enhancement factors of up to 118 times were observed with these silver nanostructures in conjugation with Rhodamine-590 fluorescent dye. These substrates are ideal candidates for a robust and inexpensive optical system with applications such as low-level fluorescence based analyte detection, single molecule imaging, and surface enhanced Raman studies. Preliminary results in single molecule experiments have also been obtained by imaging individual 3 nm and 20 nm dye-doped nanoparticles attached to the silver plasmonic gratings using epi-fluorescence microscopy.

  12. Transparent Electrochemical Gratings from a Patterned Bistable Silver Mirror.

    Science.gov (United States)

    Park, Chihyun; Na, Jongbeom; Han, Minsu; Kim, Eunkyoung

    2017-07-25

    Silver mirror patterns were formed reversibly on a polystyrene (PS)-patterned electrode to produce gratings through the electrochemical reduction of silver ions. The electrochemical gratings exhibited high transparency (T > 95%), similar to a see-through window, by matching the refractive index of the grating pattern with the surrounding medium. The gratings switch to a diffractive state upon the formation of a mirror pattern (T modulation, NIR light reflection, and on-demand heat transfer.

  13. Multicore optical fiber grating array fabrication for medical sensing applications

    Science.gov (United States)

    Westbrook, Paul S.; Feder, K. S.; Kremp, T.; Taunay, T. F.; Monberg, E.; Puc, G.; Ortiz, R.

    2015-03-01

    In this work we report on a fiber grating fabrication platform suitable for parallel fabrication of Bragg grating arrays over arbitrary lengths of multicore optical fiber. Our system exploits UV transparent coatings and has precision fiber translation that allows for quasi-continuous grating fabrication. Our system is capable of both uniform and chirped fiber grating array spectra that can meet the demands of medical sensors including high speed, accuracy, robustness and small form factor.

  14. Optically controlled tunable dispersion compensators based on pumped fiber gratings.

    Science.gov (United States)

    Shu, Xuewen; Sugden, Kate; Bennion, Ian

    2011-08-01

    We demonstrate optically tunable dispersion compensators based on pumping fiber Bragg gratings made in Er/Yb codoped fiber. The tunable dispersion for a chirped grating and also a uniform-period grating was successfully demonstrated in the experiment. The dispersion of the chirped grating was tuned from 900 to 1990 ps/nm and also from -600 to -950 ps/nm in the experiment. © 2011 Optical Society of America

  15. Engineering in-plane silicon nanowire springs for highly stretchable electronics

    Science.gov (United States)

    Xue, Zhaoguo; Dong, Taige; Zhu, Zhimin; Zhao, Yaolong; Sun, Ying; Yu, Linwei

    2018-01-01

    Crystalline silicon (c-Si) is unambiguously the most important semiconductor that underpins the development of modern microelectronics and optoelectronics, though the rigid and brittle nature of bulk c-Si makes it difficult to implement directly for stretchable applications. Fortunately, the one-dimensional (1D) geometry, or the line-shape, of Si nanowire (SiNW) can be engineered into elastic springs, which indicates an exciting opportunity to fabricate highly stretchable 1D c-Si channels. The implementation of such line-shape-engineering strategy demands both a tiny diameter of the SiNWs, in order to accommodate the strains under large stretching, and a precise growth location, orientation and path control to facilitate device integration. In this review, we will first introduce the recent progresses of an in-plane self-assembly growth of SiNW springs, via a new in-plane solid-liquid-solid (IPSLS) mechanism, where mono-like but elastic SiNW springs are produced by surface-running metal droplets that absorb amorphous Si thin film as precursor. Then, the critical growth control and engineering parameters, the mechanical properties of the SiNW springs and the prospects of developing c-Si based stretchable electronics, will be addressed. This efficient line-shape-engineering strategy of SiNW springs, accomplished via a low temperature batch-manufacturing, holds a strong promise to extend the legend of modern Si technology into the emerging stretchable electronic applications, where the high carrier mobility, excellent stability and established doping and passivation controls of c-Si can be well inherited. Project supported by the National Basic Research 973 Program (No. 2014CB921101), the National Natural Science Foundation of China (No. 61674075), the National Key Research and Development Program of China (No. 2017YFA0205003), the Jiangsu Excellent Young Scholar Program (No. BK20160020), the Scientific and Technological Support Program in Jiangsu Province (No. BE

  16. Off-plane x-ray reflection grating fabrication

    Science.gov (United States)

    Peterson, Thomas J.; DeRoo, Casey T.; Marlowe, Hannah; McEntaffer, Randall L.; Miles, Drew M.; Tutt, James H.; Schultz, Ted B.

    2015-09-01

    Off-plane X-ray diffraction gratings with precision groove profiles at the submicron scale will be used in next generation X-ray spectrometers. Such gratings will be used on a current NASA suborbital rocket mission, the Off-plane Grating Rocket Experiment (OGRE), and have application for future grating missions. The fabrication of these gratings does not come without challenges. High performance off-plane gratings must be fabricated with precise radial grating patterns, optically at surfaces, and specific facet angles. Such gratings can be made using a series of common micro-fabrication techniques. The resulting process is highly customizable, making it useful for a variety of different mission architectures. In this paper, we detail the fabrication method used to produce high performance off-plane gratings and report the results of a preliminary qualification test of a grating fabricated in this manner. The grating was tested in the off-plane `Littrow' configuration, for which the grating is most efficient for a given diffraction order, and found to achieve 42% relative efficiency in the blaze order with respect to all diffracted light.

  17. Liquid filling of photonic crystal fibres for grating writing

    DEFF Research Database (Denmark)

    Sørensen, Henrik Rokkjær; Canning, John; Lægsgaard, Jesper

    2007-01-01

    liquid filling of photonic crystal fibres reduces the scattering from air–glass interfaces during Bragg grating writing in many layered photonic crystal fibres. Within experimental uncertainty, the grating index modulation of a grating written in germanium-doped photonic crystal fibre with 10 rings...

  18. Speed and the coherence of superimposed chromatic gratings.

    Science.gov (United States)

    Bosten, J M; Smith, L; Mollon, J D

    2016-05-01

    On the basis of measurements of the perceived coherence of superimposed drifting gratings, Krauskopf and Farell (1990) proposed that motion is analysed independently in different chromatic channels. They found that two gratings appeared to slip if each modulated one of the two 'cardinal' color mechanisms S/(L+M) and L/(L+M). If the gratings were defined along intermediate color directions, observers reported a plaid, moving coherently. We hypothesised that slippage might occur in chromatic gratings if the motion signal from the S/(L+M) channel is weak and equivalent to a lower speed. We asked observers to judge coherence in two conditions. In one, S/(L+M) and L/(L+M) gratings were physically the same speed. In the other, the two gratings had perceptually matched speeds. We found that the relative incoherence of cardinal gratings is the same whether gratings are physically or perceptually matched in speed. Thus our hypothesis was firmly contradicted. In a control condition, observers were asked to judge the coherence of stationary gratings. Interestingly, the difference in judged coherence between cardinal and intermediate gratings remained as strong as it was when the gratings moved. Our results suggest a possible alternative interpretation of Krauskopf and Farell's result: the processes of object segregation may precede the analysis of the motion of chromatic gratings, and the same grouping signals may prompt object segregation in the stationary and moving cases. Copyright © 2016 Elsevier Ltd. All rights reserved.

  19. Deep-etched sinusoidal polarizing beam splitter grating.

    Science.gov (United States)

    Feng, Jijun; Zhou, Changhe; Cao, Hongchao; Lv, Peng

    2010-04-01

    A sinusoidal-shaped fused-silica grating as a highly efficient polarizing beam splitter (PBS) is investigated based on the simplified modal method. The grating structure depends mainly on the ratio of groove depth to grating period and the ratio of incident wavelength to grating period. These ratios can be used as a guideline for the grating design at different wavelengths. A sinusoidal-groove PBS grating is designed at a wavelength of 1310 nm under Littrow mounting, and the transmitted TM and TE polarized waves are mainly diffracted into the zeroth order and the -1st order, respectively. The grating profile is optimized by using rigorous coupled-wave analysis. The designed PBS grating is highly efficient (>95.98%) over the O-band wavelength range (1260-1360 nm) for both TE and TM polarizations. The sinusoidal grating can exhibit higher diffraction efficiency, larger extinction ratio, and less reflection loss than the rectangular-groove PBS grating. By applying wet etching technology on the rectangular grating, which was manufactured by holographic recording and inductively coupled plasma etching technology, the sinusoidal grating can be approximately fabricated. Experimental results are in agreement with theoretical values.

  20. Monitoring Poisson's ratio of glass fiber reinforced composites as damage index using biaxial Fiber Bragg Grating sensors

    OpenAIRE

    Yılmaz, Çağatay; Yilmaz, Cagatay; Akalın, Çağdaş; Akalin, Cagdas; Kocaman, Esat Selim; Suleman, A.; Yıldız, Mehmet; Yildiz, Mehmet

    2016-01-01

    Damage accumulation in Glass Fiber Reinforced Polymer (GFRP) composites is monitored based on Poisson's ratio measurements for three different fiber stacking sequences subjected to both quasi-static and quasi-static cyclic tensile loadings. The sensor systems utilized include a dual-extensometer, a biaxial strain gage and a novel embedded-biaxial Fiber Bragg Grating (FBG) sensor. These sensors are used concurrently to measure biaxial strain whereby the evolution of Poisson's ratio as a functi...

  1. Theoretical Investigation of Subwavelength Gratings and Vertical Cavity Lasers Employing Grating Structures

    DEFF Research Database (Denmark)

    Taghizadeh, Alireza

    This thesis deals with theoretical investigations of a newly proposed grating structure, referred to as hybrid grating (HG) as well as vertical cavity lasers based on the grating reflectors. The HG consists of a near-subwavelength grating layer and an unpatterned high-refractive-index cap layer...... directions, which is analogous to electronic quantum wells in conduction or valence bands. Several interesting configurations of heterostructures have been investigated and their potential in fundamental physics study and applications are discussed. For numerical and theoretical studies, a three...... feasibility than the HCG-based ones. Furthermore, the concept of cavity dispersion in vertical cavities is introduced and its importance in the modal properties is numerically investigated. The dispersion curvature of a cavity mode is interpreted as the effective photon mass of the cavity mode. In a vertical...

  2. PHOTOREFRACTIVE POLYMERS

    NARCIS (Netherlands)

    Morichere, D; Malliaras, G.G; Krasnikov, V.V.; Bolink, H.J; Hadziioannou, G

    The use of polymers as photorefractive materials offers many advantages : flexibility in synthesis, doping, processing and low cost. The required functionalities responsible for photorefractivity, namely charge generation, transport, trapping and linear electrooptic effect are given in the polymer

  3. Photorefractive polymers

    NARCIS (Netherlands)

    Bolink, Hendrik Jan; Hadziioannou, G

    1997-01-01

    This thesis describes the synthesis and properties of photorefractive polymers. Photorefractive polymers are materials in which the refractive index can be varied by the interaction with light. Unlike in numerous other photosensitive materials, in photorefractive materials this occurs via

  4. Smart photogalvanic running-grating interferometer

    DEFF Research Database (Denmark)

    Kukhtarev, N. V.; Kukhtareva, T.; Edwards, M. E.

    2005-01-01

    Photogalvanic effect produces actuation of periodic motion of macroscopic LiNbO3 crystal. This effect was applied to the development of an all-optical moving-grating interferometer usable for optical trapping and transport of algae chlorella microorganisms diluted in water with a concentration of...

  5. Computer simulation of multiple dynamic photorefractive gratings

    DEFF Research Database (Denmark)

    Buchhave, Preben

    1998-01-01

    The benefits of a direct visualization of space-charge grating buildup are described. The visualization is carried out by a simple repetitive computer program, which simulates the basic processes in the band-transport model and displays the result graphically or in the form of numerical data. The...

  6. Cylinder and metal grating polarization beam splitter

    Science.gov (United States)

    Yang, Junbo; Xu, Suzhi

    2017-08-01

    We propose a novel and compact metal grating polarization beam splitter (PBS) based on its different reflected and transmitted orders. The metal grating exhibits a broadband high reflectivity and polarization dependence. The rigorous coupled wave analysis is used to calculate the reflectivity and the transmitting spectra and optimize the structure parameters to realize the broadband PBS. The finite-element method is used to calculate the field distribution. The characteristics of the broadband high reflectivity, transmitting and the polarization dependence are investigated including wavelength, period, refractive index and the radius of circle grating. When grating period d = 400 nm, incident wavelength λ = 441 nm, incident angle θ = 60° and radius of circle d/5, then the zeroth reflection order R0 = 0.35 and the transmission zeroth order T0 = 0.08 for TE polarization, however, T0 = 0.34 and R0 = 0.01 for TM mode. The simple fabrication method involves only single etch step and good compatibility with complementary metal oxide semiconductor technology. PBS designed here is particularly suited for optical communication and optical information processing.

  7. Surface Fluctuation Scattering using Grating Heterodyne Spectroscopy

    DEFF Research Database (Denmark)

    Edwards, R. V.; Sirohi, R. S.; Mann, J. A.

    1982-01-01

    Heterodyne photon spectroscopy is used for the study of the viscoelastic properties of the liquid interface by studying light scattered from thermally generated surface fluctuations. A theory of a heterodyne apparatus based on a grating is presented, and the heterodyne condition is given in terms...

  8. Disorder effects in subwavelength grating metamaterial waveguides

    Czech Academy of Sciences Publication Activity Database

    Ortega-Moñux, A.; Čtyroký, Jiří; Cheben, P.; Schmid, J. H.; Wang, S.; Molina-Fernández, I.; Halíř, R.

    2017-01-01

    Roč. 25, č. 11 (2017), s. 12222-12236 ISSN 1094-4087 R&D Projects: GA ČR(CZ) GA16-00329S Institutional support: RVO:67985882 Keywords : Subwavelength grating * Integrated photonics * Diffraction effects Subject RIV: BH - Optics, Masers, Lasers OBOR OECD: Optics (including laser optics and quantum optics) Impact factor: 3.307, year: 2016

  9. Hybrid grating reflectors: Origin of ultrabroad stopband

    Energy Technology Data Exchange (ETDEWEB)

    Park, Gyeong Cheol; Taghizadeh, Alireza; Chung, Il-Sug, E-mail: ilch@fotonik.dtu.dk [DTU Fotonik, Department of Photonics Engineering, Technical University of Denmark, DK-2800 Kgs. Lyngby (Denmark)

    2016-04-04

    Hybrid grating (HG) reflectors with a high-refractive-index cap layer added onto a high contrast grating (HCG) provide a high reflectance close to 100% over a broader wavelength range than HCGs. The combination of a cap layer and a grating layer brings a strong Fabry-Perot (FP) resonance as well as a weak guided mode (GM) resonance. Most of the reflected power results from the FP resonance, while the GM resonance plays a key role in achieving a reflectance close to 100% as well as broadening the stopband. An HG sample with 7 InGaAlAs quantum wells included in the cap layer has been fabricated by directly wafer-bonding a III-V cap layer onto a Si grating layer. Its reflection property has been characterized. This heterogeneously integrated HG reflector may allow for a hybrid III-V on Si laser to be thermally efficient, which has promising prospects for silicon photonics light sources and high-speed operation.

  10. Undergraduate Experiment with Fractal Diffraction Gratings

    Science.gov (United States)

    Monsoriu, Juan A.; Furlan, Walter D.; Pons, Amparo; Barreiro, Juan C.; Gimenez, Marcos H.

    2011-01-01

    We present a simple diffraction experiment with fractal gratings based on the triadic Cantor set. Diffraction by fractals is proposed as a motivating strategy for students of optics in the potential applications of optical processing. Fraunhofer diffraction patterns are obtained using standard equipment present in most undergraduate physics…

  11. Flexible and stretchable electrodes for dielectric elastomer actuators

    Science.gov (United States)

    Rosset, Samuel; Shea, Herbert R.

    2013-02-01

    Dielectric elastomer actuators (DEAs) are flexible lightweight actuators that can generate strains of over 100 %. They are used in applications ranging from haptic feedback (mm-sized devices), to cm-scale soft robots, to meter-long blimps. DEAs consist of an electrode-elastomer-electrode stack, placed on a frame. Applying a voltage between the electrodes electrostatically compresses the elastomer, which deforms in-plane or out-of plane depending on design. Since the electrodes are bonded to the elastomer, they must reliably sustain repeated very large deformations while remaining conductive, and without significantly adding to the stiffness of the soft elastomer. The electrodes are required for electrostatic actuation, but also enable resistive and capacitive sensing of the strain, leading to self-sensing actuators. This review compares the different technologies used to make compliant electrodes for DEAs in terms of: impact on DEA device performance (speed, efficiency, maximum strain), manufacturability, miniaturization, the integration of self-sensing and self-switching, and compatibility with low-voltage operation. While graphite and carbon black have been the most widely used technique in research environments, alternative methods are emerging which combine compliance, conduction at over 100 % strain with better conductivity and/or ease of patternability, including microfabrication-based approaches for compliant metal thin-films, metal-polymer nano-composites, nanoparticle implantation, and reel-to-reel production of μm-scale patterned thin films on elastomers. Such electrodes are key to miniaturization, low-voltage operation, and widespread commercialization of DEAs.

  12. Polymer Brushes

    NARCIS (Netherlands)

    Vos, de W.M.; Kleijn, J.M.; Keizer, de A.; Cosgrove, T.; Cohen Stuart, M.A.

    2010-01-01

    A polymer brush can be defined as a dense array of polymers end-attached to an interface that stretch out into the surrounding medium. Polymer brushes have been investigated for the past 30 years and have shown to be an extremely useful tool to control interfacial properties. This review is intended

  13. Surface relief grating formation on a single crystal of 4-(dimethylamino)azobenzene

    International Nuclear Information System (INIS)

    Nakano, Hideyuki; Tanino, Takahiro; Shirota, Yasuhiko

    2005-01-01

    Surface relief grating (SRG) formation on an organic single crystal by irradiation with two coherent laser beams has been demonstrated by using 4-(dimethylamino)azobenzene (DAAB). It was found that the SRG formation was greatly depending upon both the coordination of the crystal and the polarization of the writing beams. The dependence of the polarization of writing beams on the SRG formation using the single crystal was found to be quite different from that reported for amorphous polymers and photochromic amorphous molecular materials, suggesting that the mechanism of the SRG formation on the organic crystal is somewhat different from that on amorphous materials

  14. Multichannel noninvasive human-machine interface via stretchable µm thick sEMG patches for robot manipulation

    Science.gov (United States)

    Zhou, Ying; Wang, Youhua; Liu, Runfeng; Xiao, Lin; Zhang, Qin; Huang, YongAn

    2018-01-01

    Epidermal electronics (e-skin) emerging in recent years offer the opportunity to noninvasively and wearably extract biosignals from human bodies. The conventional processes of e-skin based on standard microelectronic fabrication processes and a variety of transfer printing methods, nevertheless, unquestionably constrains the size of the devices, posing a serious challenge to collecting signals via skin, the largest organ in the human body. Herein we propose a multichannel noninvasive human-machine interface (HMI) using stretchable surface electromyography (sEMG) patches to realize a robot hand mimicking human gestures. Time-efficient processes are first developed to manufacture µm thick large-scale stretchable devices. With micron thickness, the stretchable µm thick sEMG patches show excellent conformability with human skin and consequently comparable electrical performance with conventional gel electrodes. Combined with the large-scale size, the multichannel noninvasive HMI via stretchable µm thick sEMG patches successfully manipulates the robot hand with eight different gestures, whose precision is as high as conventional gel electrodes array.

  15. Fundamental limit of light trapping in grating structures

    KAUST Repository

    Yu, Zongfu

    2010-08-11

    We use a rigorous electromagnetic approach to analyze the fundamental limit of light-trapping enhancement in grating structures. This limit can exceed the bulk limit of 4n 2, but has significant angular dependency. We explicitly show that 2D gratings provide more enhancement than 1D gratings. We also show the effects of the grating profile’s symmetry on the absorption enhancement limit. Numerical simulations are applied to support the theory. Our findings provide general guidance for the design of grating structures for light-trapping solar cells.

  16. Development of a segmented grating mount system for FIREX-1

    International Nuclear Information System (INIS)

    Ezaki, Y; Tabata, M; Kihara, M; Horiuchi, Y; Endo, M; Jitsuno, T

    2008-01-01

    A mount system for segmented meter-sized gratings has been developed, which has a high precision grating support mechanism and drive mechanism to minimize both deformation of the optical surfaces and misalignments in setting a segmented grating for obtaining sufficient performance of the pulse compressor. From analytical calculations, deformation of the grating surface is less than 1/20 lambda RMS and the estimated drive resolution for piston and tilt drive of the segmented grating is 1/20 lambda, which are both compliant with the requirements for the rear-end subsystem of FIREX-1

  17. Metrology measurements for large-aperture VPH gratings

    Science.gov (United States)

    Zheng, Jessica R.; Gers, Luke; Heijmans, Jeroen

    2013-09-01

    The High Efficiency and Resolution Multi Element Spectrograph (HERMES) for the Australian Astronomical Observatory (AAO) uses four large aperture, high angle of incidence volume phase holographic gratings (VPHG) for high resolution `Galactic archaeology' spectroscopy. The large clear aperture, the high diffraction efficiency, the line frequency homogeneity, and mosaic alignment made manufacturing and testing challenging. We developed new metrology systems at the AAO to verify the performance of these VPH gratings. The measured diffraction efficiencies and line frequency of the VPH gratings received so far meet the vendor's provided data. The wavefront quality for the Blue VPH grating is good but the Green and Red VPH gratings need to be post polishing.

  18. Stretchable Optomechanical Fiber Sensors for Pressure Determination in Compressive Medical Textiles.

    Science.gov (United States)

    Sandt, Joseph D; Moudio, Marie; Clark, J Kenji; Hardin, James; Argenti, Christian; Carty, Matthew; Lewis, Jennifer A; Kolle, Mathias

    2018-05-29

    Medical textiles are widely used to exert pressure on human tissues during treatment of post-surgical hematoma, burn-related wounds, chronic venous ulceration, and other maladies. However, the inability to dynamically sense and adjust the applied pressure often leads to suboptimal pressure application, prolonging treatment or resulting in poor patient outcomes. Here, a simple strategy for measuring sub-bandage pressure by integrating stretchable optomechanical fibers into elastic bandages is demonstrated. Specifically, these fibers possess an elastomeric photonic multilayer cladding that surrounds an extruded stretchable core filament. They can sustain repetitive strains of over 100%, and respond to deformation with a predictable and reversible color variation. Integrated into elastic textiles, which apply pressure as a function of their strain, these fibers can provide instantaneous and localized pressure feedback. These colorimetric fiber sensors are well suited for medical textiles, athletic apparel, and other smart wearable technologies, especially when repetitive, large deformations are required. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Reduced graphene oxide filled poly(dimethyl siloxane) based transparent stretchable, and touch-responsive sensors

    International Nuclear Information System (INIS)

    Ponnamma, Deepalekshmi; Sadasivuni, Kishor Kumar; Cabibihan, John-John; Yoon, W. Jong; Kumar, Bijandra

    2016-01-01

    The ongoing revolution in touch panel technology and electronics demands the need for thin films, which are flexible, stretchable, conductive, and highly touch responsive. In this regard, conductive elastomer nanocomposites offer potential solutions for these stipulations; however, viability is limited to the poor dispersion of conductive nanomaterials such as graphene into the matrix. Here, we fabricated a reduced graphene oxide (rGO) and poly(dimethylsiloxane) (PDMS) elastomer based transparent and flexible conductive touch responsive film by dispersing rGO honeycombs uniformly into PDMS elastomer through an ionic liquid (IL) modification. Pursuing a simple, scalable, and safe method of solution casting, this provides a versatile and creative design of a transparent and stretchable rGO/IL-PDMS capacitive touch responsive, where rGO acts as a sensing element. This transparent film with ∼70% transmittance exhibits approximately a five times faster response in comparison to rGO/PDMS film, with negligible degradation over time. The performance of this touch screen film is expected to have applications in the emerging field of foldable electronics.

  20. Scalable Microfabrication Procedures for Adhesive-Integrated Flexible and Stretchable Electronic Sensors

    Science.gov (United States)

    Kang, Dae Y.; Kim, Yun-Soung; Ornelas, Gladys; Sinha, Mridu; Naidu, Keerthiga; Coleman, Todd P.

    2015-01-01

    New classes of ultrathin flexible and stretchable devices have changed the way modern electronics are designed to interact with their target systems. Though more and more novel technologies surface and steer the way we think about future electronics, there exists an unmet need in regards to optimizing the fabrication procedures for these devices so that large-scale industrial translation is realistic. This article presents an unconventional approach for facile microfabrication and processing of adhesive-peeled (AP) flexible sensors. By assembling AP sensors on a weakly-adhering substrate in an inverted fashion, we demonstrate a procedure with 50% reduced end-to-end processing time that achieves greater levels of fabrication yield. The methodology is used to demonstrate the fabrication of electrical and mechanical flexible and stretchable AP sensors that are peeled-off their carrier substrates by consumer adhesives. In using this approach, we outline the manner by which adhesion is maintained and buckling is reduced for gold film processing on polydimethylsiloxane substrates. In addition, we demonstrate the compatibility of our methodology with large-scale post-processing using a roll-to-roll approach. PMID:26389915

  1. Graphene-Vertically Aligned Carbon Nanotube Hybrid on PDMS as Stretchable Electrodes.

    Science.gov (United States)

    Ding, Junjun; Fu, Shichen; Zhang, Runzhi; Boon, Eric Peter; Lee, Woo; Fisher, Frank T; Yang, Eui-Hyeok

    2017-09-11

    Stretchable electrodes are a critical component for flexible electronics such as displays, energy devices, and wearable sensors. Carbon nanotubes (CNTs) and graphene have been considered for flexible electrode applications, due to their mechanical strength, high carrier mobility, and excellent thermal conductivity. Vertically aligned carbon nanotubes (VACNTs) provide the possibility to serve as interconnects to graphene sheets as stretchable electrodes that could maintain high electrical conductivity under large tensile strain. In this work, a graphene oxide (GO) -VACNT hybrid on a PDMS substrate was demonstrated. Here, 50 μm long VACNTs were grown on a Si/SiO2 wafer substrate via atmospheric pressure chemical vapor deposition (APCVD). VACNTs were directly transferred by delamination from the Si/SiO2 to a semi-cured PDMS substrate, ensuring strong adhesion between VACNTs and PDMS upon full curing of the PDMS. GO ink was then printed on the surface of the VACNT carpet and thermally reduced to reduced graphene oxide (rGO). The sheet resistance of the rGO-VACNT hybrid was measured under uniaxial tensile strains up to 300% applied to the substrate. Under applied strain, the rGO-VACNT hybrid maintained a sheet resistant of 386±55 Ω/sq. Cyclic stretching of the rGO-VACNT hybrid was performed with up to 50 cycles at 100% maximum tensile strain, showing no increase in sheet resistance. These results demonstrate promising performance of the rGO-VACNT hybrid for flexible electronics applications. © 2017 IOP Publishing Ltd.

  2. Soft, stretchable, epidermal sensor with integrated electronics and photochemistry for measuring personal UV exposures.

    Directory of Open Access Journals (Sweden)

    Yunzhou Shi

    Full Text Available Excessive ultraviolet (UV radiation induces acute and chronic effects on the skin, eye and immune system. Personalized monitoring of UV radiation is thus paramount to measure the extent of personal sun exposure, which could vary with environment, lifestyle, and sunscreen use. Here, we demonstrate an ultralow modulus, stretchable, skin-mounted UV patch that measures personal UV doses. The patch contains functional layers of ultrathin stretchable electronics and a photosensitive patterned dye that reacts to UV radiation. Color changes in the photosensitive dyes correspond to UV radiation intensity and are analyzed with a smartphone camera. A software application has feature recognition, lighting condition correction, and quantification algorithms that detect and quantify changes in color. These color changes are then correlated with corresponding shifts in UV dose, and compared to existing UV dose risk levels. The soft mechanics of the UV patch allow for multi-day wear in the presence of sunscreen and water. Two evaluation studies serve to demonstrate the utility of the UV patch during daily activities with and without sunscreen application.

  3. Development of a Waterproof Crack-Based Stretchable Strain Sensor Based on PDMS Shielding.

    Science.gov (United States)

    Hong, Seong Kyung; Yang, Seongjin; Cho, Seong J; Jeon, Hyungkook; Lim, Geunbae

    2018-04-12

    This paper details the design of a poly(dimethylsiloxane) (PDMS)-shielded waterproof crack-based stretchable strain sensor, in which the electrical characteristics and sensing performance are not influenced by changes in humidity. This results in a higher number of potential applications for the sensor. A previously developed omni-purpose stretchable strain (OPSS) sensor was used as the basis for this work, which utilizes a metal cracking structure and provides a wide sensing range and high sensitivity. Changes in the conductivity of the OPSS sensor, based on humidity conditions, were investigated along with the potential possibility of using the design as a humidity sensor. However, to prevent conductivity variation, which can decrease the reliability and sensing ability of the OPSS sensor, PDMS was utilized as a shielding layer over the OPSS sensor. The PDMS-shielded OPSS sensor showed approximately the same electrical characteristics as previous designs, including in a high humidity environment, while maintaining its strain sensing capabilities. The developed sensor shows promise for use under high humidity conditions and in underwater applications. Therefore, considering its unique features and reliable sensing performance, the developed PDMS-shielded waterproof OPSS sensor has potential utility in a wide range of applications, such as motion monitoring, medical robotics and wearable healthcare devices.

  4. Waterproof and stretchable triboelectric nanogenerator for biomechanical energy harvesting and self-powered sensing

    Science.gov (United States)

    Chen, Xuexian; Miao, Liming; Guo, Hang; Chen, Haotian; Song, Yu; Su, Zongming; Zhang, Haixia

    2018-05-01

    We introduce a waterproof and stretchable triboelectric nanogenerator (TENG) that can be attached on the human body, such as fingers and the wrist, to harvest mechanical energy from body movement. The whole device is composed of stretchable material, making it able to endure diverse mechanical deformations and scavenge energy from them. Under gentle mechanical motions of pressing, stretching and bending, the device with an effective area of 1 × 2 cm2 can generate the peak-to-peak output current of 257.5 nA, 50.2 nA, and 33.5 nA, respectively. Besides, the TENG is tightly encapsulated, enabling it to avoid the influence of the external environment like humidity changes and harvest energy under water. Particularly, owing to the thin and soft properties of the encapsulation film, the device can respond to weak vibrations like the wrist pulse and act as a self-powered pulse sensor, which broadens its application prospects in the field of wearable energy harvesting devices and self-powered sensing systems.

  5. Self-Healable, Stretchable, Transparent Triboelectric Nanogenerators as Soft Power Sources.

    Science.gov (United States)

    Sun, Jiangman; Pu, Xiong; Liu, Mengmeng; Yu, Aifang; Du, Chunhua; Zhai, Junyi; Hu, Weiguo; Wang, Zhong Lin

    2018-06-04

    Despite the rapid advancements of soft electronics, developing compatible energy devices will be the next challenge for their viable applications. Here, we report an energy-harnessing triboelectric nanogenerator (TENG) as a soft electrical power source, which is simultaneously self-healable, stretchable, and transparent. The nanogenerator features a thin-film configuration with buckled Ag nanowires/poly(3,4-ethylenedioxythiophene) composite electrode sandwiched in room-temperature self-healable poly(dimethylsiloxane) (PDMS) elastomers. Dynamic imine bonds are introduced in PDMS networks for repairing mechanical damages (94% efficiency), while the mechanical recovery of the elastomer is imparted to the buckled electrode for electrical healing. By adjusting the buckling wavelength of the electrode, the stretchability and transparency of the soft TENG can be tuned. A TENG (∼50% stretchabitliy, ∼73% transmittance) can recover the electricity genearation (100% healing efficiency) even after accidental cutting. Finally, the conversion of biomechanical energies into electricity (∼100 V, 327 mW/m 2 ) is demonstrated by a skin-like soft TENG. Considering all these merits, this work suggests a potentially promising approach for next-generation soft power sources.

  6. Soft, stretchable, epidermal sensor with integrated electronics and photochemistry for measuring personal UV exposures.

    Science.gov (United States)

    Shi, Yunzhou; Manco, Megan; Moyal, Dominique; Huppert, Gil; Araki, Hitoshi; Banks, Anthony; Joshi, Hemant; McKenzie, Richard; Seewald, Alex; Griffin, Guy; Sen-Gupta, Ellora; Wright, Donald; Bastien, Philippe; Valceschini, Florent; Seité, Sophie; Wright, John A; Ghaffari, Roozbeh; Rogers, John; Balooch, Guive; Pielak, Rafal M

    2018-01-01

    Excessive ultraviolet (UV) radiation induces acute and chronic effects on the skin, eye and immune system. Personalized monitoring of UV radiation is thus paramount to measure the extent of personal sun exposure, which could vary with environment, lifestyle, and sunscreen use. Here, we demonstrate an ultralow modulus, stretchable, skin-mounted UV patch that measures personal UV doses. The patch contains functional layers of ultrathin stretchable electronics and a photosensitive patterned dye that reacts to UV radiation. Color changes in the photosensitive dyes correspond to UV radiation intensity and are analyzed with a smartphone camera. A software application has feature recognition, lighting condition correction, and quantification algorithms that detect and quantify changes in color. These color changes are then correlated with corresponding shifts in UV dose, and compared to existing UV dose risk levels. The soft mechanics of the UV patch allow for multi-day wear in the presence of sunscreen and water. Two evaluation studies serve to demonstrate the utility of the UV patch during daily activities with and without sunscreen application.

  7. The Language of Glove: Wireless gesture decoder with low-power and stretchable hybrid electronics.

    Directory of Open Access Journals (Sweden)

    Timothy F O'Connor

    Full Text Available This communication describes a glove capable of wirelessly translating the American Sign Language (ASL alphabet into text displayable on a computer or smartphone. The key components of the device are strain sensors comprising a piezoresistive composite of carbon particles embedded in a fluoroelastomer. These sensors are integrated with a wearable electronic module consisting of digitizers, a microcontroller, and a Bluetooth radio. Finite-element analysis predicts a peak strain on the sensors of 5% when the knuckles are fully bent. Fatigue studies suggest that the sensors successfully detect the articulation of the knuckles even when bent to their maximal degree 1,000 times. In concert with an accelerometer and pressure sensors, the glove is able to translate all 26 letters of the ASL alphabet. Lastly, data taken from the glove are used to control a virtual hand; this application suggests new ways in which stretchable and wearable electronics can enable humans to interface with virtual environments. Critically, this system was constructed of components costing less than $100 and did not require chemical synthesis or access to a cleanroom. It can thus be used as a test bed for materials scientists to evaluate the performance of new materials and flexible and stretchable hybrid electronics.

  8. Development of a Waterproof Crack-Based Stretchable Strain Sensor Based on PDMS Shielding

    Directory of Open Access Journals (Sweden)

    Seong Kyung Hong

    2018-04-01

    Full Text Available This paper details the design of a poly(dimethylsiloxane (PDMS-shielded waterproof crack-based stretchable strain sensor, in which the electrical characteristics and sensing performance are not influenced by changes in humidity. This results in a higher number of potential applications for the sensor. A previously developed omni-purpose stretchable strain (OPSS sensor was used as the basis for this work, which utilizes a metal cracking structure and provides a wide sensing range and high sensitivity. Changes in the conductivity of the OPSS sensor, based on humidity conditions, were investigated along with the potential possibility of using the design as a humidity sensor. However, to prevent conductivity variation, which can decrease the reliability and sensing ability of the OPSS sensor, PDMS was utilized as a shielding layer over the OPSS sensor. The PDMS-shielded OPSS sensor showed approximately the same electrical characteristics as previous designs, including in a high humidity environment, while maintaining its strain sensing capabilities. The developed sensor shows promise for use under high humidity conditions and in underwater applications. Therefore, considering its unique features and reliable sensing performance, the developed PDMS-shielded waterproof OPSS sensor has potential utility in a wide range of applications, such as motion monitoring, medical robotics and wearable healthcare devices.

  9. Soft, stretchable, epidermal sensor with integrated electronics and photochemistry for measuring personal UV exposures

    Science.gov (United States)

    Shi, Yunzhou; Manco, Megan; Moyal, Dominique; Huppert, Gil; Araki, Hitoshi; Banks, Anthony; Joshi, Hemant; McKenzie, Richard; Seewald, Alex; Griffin, Guy; Sen-Gupta, Ellora; Wright, Donald; Bastien, Philippe; Valceschini, Florent; Seité, Sophie; Wright, John A.; Ghaffari, Roozbeh; Rogers, John; Balooch, Guive

    2018-01-01

    Excessive ultraviolet (UV) radiation induces acute and chronic effects on the skin, eye and immune system. Personalized monitoring of UV radiation is thus paramount to measure the extent of personal sun exposure, which could vary with environment, lifestyle, and sunscreen use. Here, we demonstrate an ultralow modulus, stretchable, skin-mounted UV patch that measures personal UV doses. The patch contains functional layers of ultrathin stretchable electronics and a photosensitive patterned dye that reacts to UV radiation. Color changes in the photosensitive dyes correspond to UV radiation intensity and are analyzed with a smartphone camera. A software application has feature recognition, lighting condition correction, and quantification algorithms that detect and quantify changes in color. These color changes are then correlated with corresponding shifts in UV dose, and compared to existing UV dose risk levels. The soft mechanics of the UV patch allow for multi-day wear in the presence of sunscreen and water. Two evaluation studies serve to demonstrate the utility of the UV patch during daily activities with and without sunscreen application. PMID:29293664

  10. Graphene—vertically aligned carbon nanotube hybrid on PDMS as stretchable electrodes

    Science.gov (United States)

    Ding, Junjun; Fu, Shichen; Zhang, Runzhi; Boon, Eric; Lee, Woo; Fisher, Frank T.; Yang, Eui-Hyeok

    2017-11-01

    Stretchable electrodes are a critical component for flexible electronics such as displays, energy devices, and wearable sensors. Carbon nanotubes (CNTs) and graphene have been considered for flexible electrode applications, due to their mechanical strength, high carrier mobility, and excellent thermal conductivity. Vertically aligned carbon nanotubes (VACNTs) provide the possibility to serve as interconnects to graphene sheets as stretchable electrodes that could maintain high electrical conductivity under large tensile strain. In this work, a graphene oxide (GO)-VACNT hybrid on a PDMS substrate was demonstrated. Here, 50 μm long VACNTs were grown on a Si/SiO2 wafer substrate via atmospheric pressure chemical vapor deposition. VACNTs were directly transferred by delamination from the Si/SiO2 to a semi-cured PDMS substrate, ensuring strong adhesion between VACNTs and PDMS upon full curing of the PDMS. GO ink was then printed on the surface of the VACNT carpet and thermally reduced to reduced graphene oxide (rGO). The sheet resistance of the rGO-VACNT hybrid was measured under uniaxial tensile strains up to 300% applied to the substrate. Under applied strain, the rGO-VACNT hybrid maintained a sheet resistant of 386 ± 55 Ω/sq. Cyclic stretching of the rGO-VACNT hybrid was performed with up to 50 cycles at 100% maximum tensile strain, showing no increase in sheet resistance. These results demonstrate promising performance of the rGO-VACNT hybrid for flexible electronics applications.

  11. Wearable, wireless gas sensors using highly stretchable and transparent structures of nanowires and graphene

    Science.gov (United States)

    Park, Jihun; Kim, Joohee; Kim, Kukjoo; Kim, So-Yun; Cheong, Woon Hyung; Park, Kyeongmin; Song, Joo Hyeb; Namgoong, Gyeongho; Kim, Jae Joon; Heo, Jaeyeong; Bien, Franklin; Park, Jang-Ung

    2016-05-01

    Herein, we report the fabrication of a highly stretchable, transparent gas sensor based on silver nanowire-graphene hybrid nanostructures. Due to its superb mechanical and optical characteristics, the fabricated sensor demonstrates outstanding and stable performances even under extreme mechanical deformation (stable until 20% of strain). The integration of a Bluetooth system or an inductive antenna enables the wireless operation of the sensor. In addition, the mechanical robustness of the materials allows the device to be transferred onto various nonplanar substrates, including a watch, a bicycle light, and the leaves of live plants, thereby achieving next-generation sensing electronics for the `Internet of Things' area.Herein, we report the fabrication of a highly stretchable, transparent gas sensor based on silver nanowire-graphene hybrid nanostructures. Due to its superb mechanical and optical characteristics, the fabricated sensor demonstrates outstanding and stable performances even under extreme mechanical deformation (stable until 20% of strain). The integration of a Bluetooth system or an inductive antenna enables the wireless operation of the sensor. In addition, the mechanical robustness of the materials allows the device to be transferred onto various nonplanar substrates, including a watch, a bicycle light, and the leaves of live plants, thereby achieving next-generation sensing electronics for the `Internet of Things' area. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr01468b

  12. Initial rigid response and softening transition of highly stretchable kirigami sheet materials.

    Science.gov (United States)

    Isobe, Midori; Okumura, Ko

    2016-04-27

    We study, experimentally and theoretically, the mechanical response of sheet materials on which line cracks or cuts are arranged in a simple pattern. Such sheet materials, often called kirigami (the Japanese words, kiri and gami, stand for cut and paper, respectively), demonstrate a unique mechanical response promising for various engineering applications such as stretchable batteries: kirigami sheets possess a mechanical regime in which sheets are highly stretchable and very soft compared with the original sheets without line cracks, by virtue of out-of-plane deformation. However, this regime starts after a transition from an initial stiff regime governed by in-plane deformation. In other words, the softness of the kirigami structure emerges as a result of a transition from the two-dimensional to three-dimensional deformation, i.e., from stretching to bending. We clarify the physical origins of the transition and mechanical regimes, which are revealed to be governed by simple scaling laws. The results could be useful for controlling and designing the mechanical response of sheet materials including cell sheets for medical regeneration and relevant to the development of materials with tunable stiffness and mechanical force sensors.

  13. Reduced graphene oxide filled poly(dimethyl siloxane) based transparent stretchable, and touch-responsive sensors

    Energy Technology Data Exchange (ETDEWEB)

    Ponnamma, Deepalekshmi [Center for Advanced Materials, Qatar University, P. O. Box 2713, Doha (Qatar); Sadasivuni, Kishor Kumar; Cabibihan, John-John [Mechanical and Industrial Engineering, Qatar University, P.O. Box 2713, Doha (Qatar); Yoon, W. Jong [School of Science, Technology, Engineering, and Mathematics, University of Washington, Bothell, Washington 98011 (United States); Kumar, Bijandra, E-mail: bijandra.kumar@louisville.edu [Conn Center for Renewable Energy Research, University of Louisville, Louisville, Kentucky 40292 (United States); Research and Development Centre in Pharmaceutical Science and Applied Chemistry, Poona College of Pharmacy, Bharati Vidyapeeth Deemed University Erandawane, Pune 411038 (India)

    2016-04-25

    The ongoing revolution in touch panel technology and electronics demands the need for thin films, which are flexible, stretchable, conductive, and highly touch responsive. In this regard, conductive elastomer nanocomposites offer potential solutions for these stipulations; however, viability is limited to the poor dispersion of conductive nanomaterials such as graphene into the matrix. Here, we fabricated a reduced graphene oxide (rGO) and poly(dimethylsiloxane) (PDMS) elastomer based transparent and flexible conductive touch responsive film by dispersing rGO honeycombs uniformly into PDMS elastomer through an ionic liquid (IL) modification. Pursuing a simple, scalable, and safe method of solution casting, this provides a versatile and creative design of a transparent and stretchable rGO/IL-PDMS capacitive touch responsive, where rGO acts as a sensing element. This transparent film with ∼70% transmittance exhibits approximately a five times faster response in comparison to rGO/PDMS film, with negligible degradation over time. The performance of this touch screen film is expected to have applications in the emerging field of foldable electronics.

  14. The Language of Glove: Wireless gesture decoder with low-power and stretchable hybrid electronics.

    Science.gov (United States)

    O'Connor, Timothy F; Fach, Matthew E; Miller, Rachel; Root, Samuel E; Mercier, Patrick P; Lipomi, Darren J

    2017-01-01

    This communication describes a glove capable of wirelessly translating the American Sign Language (ASL) alphabet into text displayable on a computer or smartphone. The key components of the device are strain sensors comprising a piezoresistive composite of carbon particles embedded in a fluoroelastomer. These sensors are integrated with a wearable electronic module consisting of digitizers, a microcontroller, and a Bluetooth radio. Finite-element analysis predicts a peak strain on the sensors of 5% when the knuckles are fully bent. Fatigue studies suggest that the sensors successfully detect the articulation of the knuckles even when bent to their maximal degree 1,000 times. In concert with an accelerometer and pressure sensors, the glove is able to translate all 26 letters of the ASL alphabet. Lastly, data taken from the glove are used to control a virtual hand; this application suggests new ways in which stretchable and wearable electronics can enable humans to interface with virtual environments. Critically, this system was constructed of components costing less than $100 and did not require chemical synthesis or access to a cleanroom. It can thus be used as a test bed for materials scientists to evaluate the performance of new materials and flexible and stretchable hybrid electronics.

  15. Stretchable gold conductors embedded in PDMS and patterned by photolithography: fabrication and electromechanical characterization

    International Nuclear Information System (INIS)

    Adrega, T; Lacour, S P

    2010-01-01

    Stretchable gold conductors embedded in polydimethylsiloxane (PDMS) films were successfully prepared using standard photolithography. The minimum feature sizes patterned in the metal film and PDMS encapsulation are 10 µm and 20 µm, respectively. The micro-patterned conductors are robust to uni-axial (1D) and radial (2D) stretching with applied strains of tens of percent. The electrical response of the conductors follows a nonlinear increase with strain, and is reversible. The extensive stretchability of the conductors relies on a randomly and independently distributed network of micro-cracks (∼100 nm long) in the metal film on PDMS. The micro-cracks elongate to a few microns length both in the stretching and normal directions in 1D stretching but during 2D stretching, the micro-cracks grow and form 'dry mud' islands leaving the gold microstructure inside the islands intact. Patterning metallic thin films directly onto elastomeric substrates opens a promising route for microelectrodes and interconnects for soft and ultra-compliant MEMS and electronic devices.

  16. Talbot Carpet Simulation for X-ray grating interferometer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Youngju; Oh, Ohsung; Jeong, Hanseong; Kim, Jeongho; Lee, Seung Wook [Pusan National University, Busan (Korea, Republic of); Kim, Jongyul; Moon, Myungkook [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2015-05-15

    In this study, Talbot carpet simulator has been developed to visualize the X-ray grating interference patterns in grating interferometer. We have simulated X-ray interference for a variety of simulations and demonstrated a few examples in this summary. Grating interferometer produces interference of X-ray called Talbot pattern with gratings manufactured in micro scale. Talbot pattern is self-images of phase grating which develops interference as beam splitter that is one of gratings consisted of interferometer. As the other gratings, there are source grating makes coherence and analyze grating is used to analyze interference onto detector. Talbot carpet has been studied as the beam behavior which is distinguished with common X-ray imaging systems. It is helpful to understand grating interferometer and possible to expect beams' oscillation for designing theoretically. We confirm pattern has periodicity produced by interference after pi and pi/2 phase grating and changes in the perpendicular direction to entrance face according to phase objects.

  17. Nanostructure Diffraction Gratings for Integrated Spectroscopy and Sensing

    Science.gov (United States)

    Guo, Junpeng (Inventor)

    2016-01-01

    The present disclosure pertains to metal or dielectric nanostructures of the subwavelength scale within the grating lines of optical diffraction gratings. The nanostructures have surface plasmon resonances or non-plasmon optical resonances. A linear photodetector array is used to capture the resonance spectra from one of the diffraction orders. The combined nanostructure super-grating and photodetector array eliminates the use of external optical spectrometers for measuring surface plasmon or optical resonance frequency shift caused by the presence of chemical and biological agents. The nanostructure super-gratings can be used for building integrated surface enhanced Raman scattering (SERS) spectrometers. The nanostructures within the diffraction grating lines enhance Raman scattering signal light while the diffraction grating pattern of the nanostructures diffracts Raman scattering light to different directions of propagation according to their wavelengths. Therefore, the nanostructure super-gratings allows for the use of a photodetector array to capture the surface enhanced Raman scattering spectra.

  18. Precise rotational alignment of x-ray transmission diffraction gratings

    International Nuclear Information System (INIS)

    Hill, S.L.

    1988-01-01

    Gold transmission diffraction gratings used for x-ray spectroscopy must sometimes be rotationally aligned to the axis of a diagnostic instrument to within sub-milliradian accuracy. We have fabricated transmission diffraction gratings with high line-densities (grating period of 200 and 300 nm) using uv holographic and x-ray lithography. Since the submicron features of the gratings are not optically visible, precision alignment is time consuming and difficult to verify in situ. We have developed a technique to write an optically visible alignment pattern onto these gratings using a scanning electron microscope (SEM). At high magnification (15000 X) several submicron lines of the grating are observable in the SEM, making it possible to write an alignment pattern parallel to the grating lines in an electron-beam-sensitive coating that overlays the grating. We create an alignment pattern by following a 1-cm-long grating line using the SEM's joystick-controlled translation stage. By following the same grating line we are assured the traveled direction of the SEM electron beam is parallel to the grating to better than 10 μradian. The electron-beam-exposed line-width can be large (5 to 15 μm wide) depending on the SEM magnification, and is therefore optically visible. The exposed pattern is eventually made a permanent feature of the grating by ion beam etching or gold electroplating. The pattern can be used to accurately align the grating to the axis of a diagnostic instrument. More importantly, the alignment of the grating can be quickly verified in situ

  19. Electrically and spatially controllable PDLC phase gratings for diffraction and modulation of laser beams

    Energy Technology Data Exchange (ETDEWEB)

    Hadjichristov, Georgi B., E-mail: georgibh@issp.bas.bg [Laboratory of Optics and Spectroscopy, Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., BG-1784 Sofia (Bulgaria); Marinov, Yordan G.; Petrov, Alexander G. [Laboratory of Biomolecular Layers, Georgi Nadjakov Institute of Solid State Physics, Bulgarian Academy of Sciences, 72 Tzarigradsko Chaussee Blvd., BG-1784 Sofia, Bulgaria (Bulgaria)

    2016-03-25

    We present a study on electrically- and spatially-controllable laser beam diffraction, electrooptic (EO) phase modulation, as well as amplitude-frequency EO modulation by single-layer microscale polymer-dispersed liquid crystal (PDLC) phase gratings (PDLC SLPGs) of interest for device applications. PDLC SLPGs were produced from nematic liquid crystal (LC) E7 in photo-curable NOA65 polymer. The wedge-formed PDLC SLPGs have a continuously variable thickness (2–25 µm). They contain LC droplets of diameters twice as the layer thickness, with a linear-gradient size distribution along the wedge. By applying alternating-current (AC) electric field, the PDLC SLPGs produce efficient: (i) diffraction splitting of transmitted laser beams; (ii) spatial redistribution of diffracted light intensity; (iii) optical phase modulation; (iv) amplitude-frequency modulation, all controllable by the driven AC field and the droplet size gradient.

  20. WDM hybrid microoptical transceiver with Bragg volume grating

    Science.gov (United States)

    Jeřábek, Vitezslav; Armas, Julio; Mareš, David; Prajzler, Václav

    2012-02-01

    The paper presents the design, simulation and construction results of the wavelength division multiplex bidirectional transceiver module (WDM transceiver) for the passive optical network (PON) of a fiber to the home (FTTH) topology network. WDM transceiver uses a microoptical hybrid integration technology with volume holographic Bragg grating triplex filter -VHGT and a collimation lenses imagine system for wavelength multiplexing/ demultiplexing. This transmission type VHGT filter has high diffraction angle, very low insertion loses and optical crosstalk, which guide to very good technical parameters of transceiver module. WDM transceiver has been constructed using system of a four micromodules in the new circle topology. The optical micromodule with VHGT filter and collimation and decollimation lenses, two optoelectronics microwave receiver micromodules for receiving download information (internet and digital TV signals) and optoelectronic transmitter micromodule for transmitting upload information. In the paper is presented the optical analysis of the optical imagine system by ray-transfer matrix. We compute and measure VHGT characteristics such as diffraction angle, diffraction efficiency and diffraction crosstalk of the optical system for 1310, 1490 and 1550 nm wavelength radiation. For the design of optoelectronic receiver micromodule was used the low signal electrical equivalent circuit for the dynamic performance signal analysis. In the paper is presented the planar form WDM transceiver with polymer optical waveguides and two stage interference demultiplexing optical filter as well.

  1. Electromagnetically induced grating with Rydberg atoms

    Science.gov (United States)

    Asghar, Sobia; Ziauddin, Qamar, Shahid; Qamar, Sajid

    2016-09-01

    We present a scheme to realize electromagnetically induced grating in an ensemble of strongly interacting Rydberg atoms, which act as superatoms due to the dipole blockade mechanism. The ensemble of three-level cold Rydberg-dressed (87Rb) atoms follows a cascade configuration where a strong standing-wave control field and a weak probe pulse are employed. The diffraction intensity is influenced by the strength of the probe intensity, the control field strength, and the van der Waals (vdW) interaction. It is noticed that relatively large first-order diffraction can be obtained for low-input intensity with a small vdW shift and a strong control field. The scheme can be considered as an amicable solution to realize the atomic grating at the microscopic level, which can provide background- and dark-current-free diffraction.

  2. Theory of Fiber Optical Bragg Grating: Revisited

    Science.gov (United States)

    Tai, H.

    2003-01-01

    The reflected signature of an optical fiber Bragg grating is analyzed using the transfer function method. This approach is capable to cast all relevant quantities into proper places and provides a better physical understanding. The relationship between reflected signal, number of periods, index of refraction, and reflected wave phase is elucidated. The condition for which the maximum reflectivity is achieved is fully examined. We also have derived an expression to predict the reflectivity minima accurately when the reflected wave is detuned. Furthermore, using the segmented potential approach, this model can handle arbitrary index of refraction profiles and compare the strength of optical reflectivity of different profiles. The condition of a non-uniform grating is also addressed.

  3. Straw combustion on slow-moving grates

    DEFF Research Database (Denmark)

    Kær, Søren Knudsen

    2005-01-01

    Combustion of straw in grate-based boilers is often associated with high emission levels and relatively poor fuel burnout. A numerical grate combustion model was developed to assist in improving the combustion performance of these boilers. The model is based on a one-dimensional ‘‘walking......-column’’ approach and includes the energy equations for both the fuel and the gas accounting for heat transfer between the two phases. The model gives important insight into the combustion process and provides inlet conditions for a computational fluid dynamics analysis of the freeboard. The model predictions...... indicate the existence of two distinct combustion modes. Combustion air temperature and mass flow-rate are the two parameters determining the mode. There is a significant difference in reaction rates (ignition velocity) and temperature levels between the two modes. Model predictions were compared...

  4. Varied line-space gratings: past, present and future

    International Nuclear Information System (INIS)

    Hettrick, M.C.

    1985-08-01

    A classically ruled diffraction grating consists of grooves which are equidistant, straight and parallel. Conversely, the so-called ''holographic'' grating (formed by the interfering waves of coherent visible light), although severely constrained by the recording wavelength and recording geometry, has grooves which are typically neither equidistant, straight nor parallel. In contrast, a varied line-space (VLS) grating, in common nomenclature, is a design in which the groove positions are relatively unconstrained yet possess sufficient symmetry to permit mechanical ruling. Such seemingly exotic gratings are no longer only a theoretical curiosity, but have been ruled and used in a wide variety of applications. These include: (1) aberration-corrected normal incidence concave gratings for Seya-Namioka monochromators and optical de-multiplexers, (2) flat-field grazing incidence concave gratings for plasma diagnostics, (3) aberration-corrected grazing incidence plane gratings for space-borne spectrometers, (4) focusing grazing incidence plane grating for synchrotron radiation monochromators, and (5) wavefront generators for visible interferometry of optical surfaces (particularly aspheres). Future prospects of VLS gratings as dispersing elements, wavefront correctors and beamsplitters appear promising. The author discusses the history of VLS gratings, their present applications, and their potential in the future. 61 refs., 24 figs

  5. Response of fiber Bragg gratings to longitudinal ultrasonic waves.

    Science.gov (United States)

    Minardo, Aldo; Cusano, Andrea; Bernini, Romeo; Zeni, Luigi; Giordano, Michele

    2005-02-01

    In the last years, fiber optic sensors have been widely exploited for several sensing applications, including static and dynamic strain measurements up to acoustic detection. Among these, fiber Bragg grating sensors have been indicated as the ideal candidate for practical structural health monitoring in light of their unique advantages over conventional sensing devices. Although this class of sensors has been successfully tested for static and low-frequency measurements, the identification of sensor performances for high-frequency detection, including acoustic emission and ultrasonic investigations, is required. To this aim, the analysis of feasibilty on the use of fiber Bragg grating sensors as ultrasonic detectors has been carried out. In particular, the response of fiber Bragg gratings subjected to the longitudinal ultrasonic (US) field has been theoretically and numerically investigated. Ultrasonic field interaction has been modeled, taking into account the direct deformation of the grating pitch combined with changes in local refractive index due to the elasto-optic effect. Numerical results, obtained for both uniform and Gaussian-apodized fiber Bragg gratings, show that the grating spectrum is strongly influenced by the US field in terms of shape and central wavelength. In particular, a key parameter affecting the grating response is the ratio between the US wavelength and the grating length. Normal operation characterized by changes in wavelength of undistorted Bragg peak is possible only for US wavelengths longer than the grating length. For US wavelengths approaching the grating length, the wavelength change is accompanied by subpeaks formation and main peak amplitude modulation. This effect can be attributed to the nonuniformity of the US perturbation along the grating length. At very high US frequencies, the grating is not sensitive any longer. The results of this analysis provide useful tools for the design of grating-based ultrasound sensors for

  6. Polymer Electrolytes

    Science.gov (United States)

    Hallinan, Daniel T.; Balsara, Nitash P.

    2013-07-01

    This review article covers applications in which polymer electrolytes are used: lithium batteries, fuel cells, and water desalination. The ideas of electrochemical potential, salt activity, and ion transport are presented in the context of these applications. Potential is defined, and we show how a cell potential measurement can be used to ascertain salt activity. The transport parameters needed to fully specify a binary electrolyte (salt + solvent) are presented. We define five fundamentally different types of homogeneous electrolytes: type I (classical liquid electrolytes), type II (gel electrolytes), type III (dry polymer electrolytes), type IV (dry single-ion-conducting polymer electrolytes), and type V (solvated single-ion-conducting polymer electrolytes). Typical values of transport parameters are provided for all types of electrolytes. Comparison among the values provides insight into the transport mechanisms occurring in polymer electrolytes. It is desirable to decouple the mechanical properties of polymer electrolyte membranes from the ionic conductivity. One way to accomplish this is through the development of microphase-separated polymers, wherein one of the microphases conducts ions while the other enhances the mechanical rigidity of the heterogeneous polymer electrolyte. We cover all three types of conducting polymer electrolyte phases (types III, IV, and V). We present a simple framework that relates the transport parameters of heterogeneous electrolytes to homogeneous analogs. We conclude by discussing electrochemical stability of electrolytes and the effects of water contamination because of their relevance to applications such as lithium ion batteries.

  7. Star Polymers.

    Science.gov (United States)

    Ren, Jing M; McKenzie, Thomas G; Fu, Qiang; Wong, Edgar H H; Xu, Jiangtao; An, Zesheng; Shanmugam, Sivaprakash; Davis, Thomas P; Boyer, Cyrille; Qiao, Greg G

    2016-06-22

    Recent advances in controlled/living polymerization techniques and highly efficient coupling chemistries have enabled the facile synthesis of complex polymer architectures with controlled dimensions and functionality. As an example, star polymers consist of many linear polymers fused at a central point with a large number of chain end functionalities. Owing to this exclusive structure, star polymers exhibit some remarkable characteristics and properties unattainable by simple linear polymers. Hence, they constitute a unique class of technologically important nanomaterials that have been utilized or are currently under audition for many applications in life sciences and nanotechnologies. This article first provides a comprehensive summary of synthetic strategies towards star polymers, then reviews the latest developments in the synthesis and characterization methods of star macromolecules, and lastly outlines emerging applications and current commercial use of star-shaped polymers. The aim of this work is to promote star polymer research, generate new avenues of scientific investigation, and provide contemporary perspectives on chemical innovation that may expedite the commercialization of new star nanomaterials. We envision in the not-too-distant future star polymers will play an increasingly important role in materials science and nanotechnology in both academic and industrial settings.

  8. Polymer chemistry (revised edition)

    International Nuclear Information System (INIS)

    Kim, Jae Mum

    1987-02-01

    This book deals with polymer chemistry, which is divided into fourteen chapters. The contents of this book are development of polymer chemistry, conception of polymer, measurement of polymer chemistry, conception of polymer, measurement of polymer, molecule structure of polymer, thermal prosperities of solid polymer, basic theory of polymerization, radical polymerization, ion polymerization, radical polymerization, copolymerization, polymerization by step-reaction, polymer reaction, crown polymer and inorganic polymer on classification and process of creation such as polymeric sulfur and carbon fiber.

  9. An X-ray grazing incidence phase multilayer grating

    CERN Document Server

    Chernov, V A; Mytnichenko, S V

    2001-01-01

    An X-ray grazing incidence phase multilayer grating, representing a thin grating placed on a multilayer mirror, is proposed. A high efficiency of grating diffraction can be obtained by the possibility of changing the phase shift of the wave diffracted from the multilayer under the Bragg and total external reflection conditions. A grazing incidence phase multilayer grating consisting of Pt grating stripes on a Ni/C multilayer and optimized for the hard X-ray range was fabricated. Its diffraction properties were studied at photon energies of 7 and 8 keV. The obtained maximum value of the diffraction efficiency of the +1 grating order was 9% at 7 keV and 6.5% at 8 keV. The data obtained are in a rather good accordance with the theory.

  10. Phasor analysis of binary diffraction gratings with different fill factors

    International Nuclear Information System (INIS)

    MartInez, Antonio; Sanchez-Lopez, Ma del Mar; Moreno, Ignacio

    2007-01-01

    In this work, we present a simple analysis of binary diffraction gratings with different slit widths relative to the grating period. The analysis is based on a simple phasor technique directly derived from the Huygens principle. By introducing a slit phasor and a grating phasor, the intensity of the diffracted orders and the grating's resolving power can be easily obtained without applying the usual Fourier transform operations required for these calculations. The proposed phasor technique is mathematically equivalent to the Fourier transform calculation of the diffraction order amplitude, and it can be useful to explain binary diffraction gratings in a simple manner in introductory physics courses. This theoretical analysis is illustrated with experimental results using a liquid crystal device to display diffraction gratings with different fill factors

  11. Phasor analysis of binary diffraction gratings with different fill factors

    Energy Technology Data Exchange (ETDEWEB)

    MartInez, Antonio [Departamento de Ciencia de Materiales, Optica y TecnologIa Electronica, Universidad Miguel Hernandez, 03202 Elche (Spain); Sanchez-Lopez, Ma del Mar [Instituto de BioingenierIa y Departamento de Fisica y Arquitectura de Computadores, Universidad Miguel Hernandez, 03202 Elche (Spain); Moreno, Ignacio [Departamento de Ciencia de Materiales, Optica y TecnologIa Electronica, Universidad Miguel Hernandez, 03202 Elche (Spain)

    2007-09-11

    In this work, we present a simple analysis of binary diffraction gratings with different slit widths relative to the grating period. The analysis is based on a simple phasor technique directly derived from the Huygens principle. By introducing a slit phasor and a grating phasor, the intensity of the diffracted orders and the grating's resolving power can be easily obtained without applying the usual Fourier transform operations required for these calculations. The proposed phasor technique is mathematically equivalent to the Fourier transform calculation of the diffraction order amplitude, and it can be useful to explain binary diffraction gratings in a simple manner in introductory physics courses. This theoretical analysis is illustrated with experimental results using a liquid crystal device to display diffraction gratings with different fill factors.

  12. Towards freeform curved blazed gratings using diamond machining

    Science.gov (United States)

    Bourgenot, C.; Robertson, D. J.; Stelter, D.; Eikenberry, S.

    2016-07-01

    Concave blazed gratings greatly simplify the architecture of spectrographs by reducing the number of optical components. The production of these gratings using diamond-machining offers practically no limits in the design of the grating substrate shape, with the possibility of making large sag freeform surfaces unlike the alternative and traditional method of holography and ion etching. In this paper, we report on the technological challenges and progress in the making of these curved blazed gratings using an ultra-high precision 5 axes Moore-Nanotech machine. We describe their implementation in an integral field unit prototype called IGIS (Integrated Grating Imaging Spectrograph) where freeform curved gratings are used as pupil mirrors. The goal is to develop the technologies for the production of the next generation of low-cost, compact, high performance integral field unit spectrometers.

  13. Apodized grating coupler using fully-etched nanostructures

    International Nuclear Information System (INIS)

    Wu Hua; Li Chong; Guo Xia; Li Zhi-Yong

    2016-01-01

    A two-dimensional apodized grating coupler for interfacing between single-mode fiber and photonic circuit is demonstrated in order to bridge the mode gap between the grating coupler and optical fiber. The grating grooves of the grating couplers are realized by columns of fully etched nanostructures, which are utilized to digitally tailor the effective refractive index of each groove in order to obtain the Gaussian-like output diffractive mode and then enhance the coupling efficiency. Compared with that of the uniform grating coupler, the coupling efficiency of the apodized grating coupler is increased by 4.3% and 5.7%, respectively, for the nanoholes and nanorectangles as refractive index tunes layer. (paper)

  14. Grate-firing of biomass for heat and power production

    DEFF Research Database (Denmark)

    Yin, Chungen; Rosendahl, Lasse; Kær, Søren Knudsen

    2008-01-01

    bed on the grate, and the advanced secondary air supply (a real breakthrough in this technology) are highlighted for grate-firing systems. Amongst all the issues or problems associated with grate-fired boilers burning biomass, primary pollutant formation and control, deposition formation and corrosion......As a renewable and environmentally friendly energy source, biomass (i.e., any organic non-fossil fuel) and its utilization are gaining an increasingly important role worldwide Grate-firing is one of the main competing technologies in biomass combustion for heat and power production, because it can...... combustion mechanism, the recent breakthrough in the technology, the most pressing issues, the current research and development activities, and the critical future problems to be resolved. The grate assembly (the most characteristic element in grate-fired boilers), the key combustion mechanism in the fuel...

  15. Polarization effects in polymer FBGs: study and use for transverse force sensing

    DEFF Research Database (Denmark)

    Hu, Xuehao; Saez-Rodriguez, David; Marques, Carlos

    2015-01-01

    Bragg gratings photo-inscribed in polymer optical fibers (POFs) are more sensitive to temperature and pressure than their silica counterparts, because of their larger thermo-optic coefficient and smaller Young's modulus. Polymer optical fiber Bragg gratings (POFBGs) are most often photo-written i...... the PDL response of FBGs manufactured in step-index POFs. As the force induced birefringence adds to the photo-induced one, a force dependent evolution of the PDL maximum value was noticed, with a good temperature-insensitivity. (C) 2015 Optical Society of America...

  16. Direct Printing of Stretchable Elastomers for Highly Sensitive Capillary Pressure Sensors.

    Science.gov (United States)

    Liu, Wenguang; Yan, Chaoyi

    2018-03-28

    We demonstrate the successful fabrication of highly sensitive capillary pressure sensors using an innovative 3D printing method. Unlike conventional capacitive pressure sensors where the capacitance changes were due to the pressure-induced interspace variations between the parallel plate electrodes, in our capillary sensors the capacitance was determined by the extrusion and extraction of liquid medium and consequent changes of dielectric constants. Significant pressure sensitivity advances up to 547.9 KPa -1 were achieved. Moreover, we suggest that our innovative capillary pressure sensors can adopt a wide range of liquid mediums, such as ethanol, deionized water, and their mixtures. The devices also showed stable performances upon repeated pressing cycles. The direct and versatile printing method combined with the significant performance advances are expected to find important applications in future stretchable and wearable electronics.

  17. Stretchable glucose biofuel cell with wirings made of multiwall carbon nanotubes

    International Nuclear Information System (INIS)

    Fujimagari, Yusuke; Nishioka, Yasushiro

    2015-01-01

    In this study, we fabricated a flexible and stretchable glucose-biofuel cell with wirings made of multi wall carbon nanotube (MWCNTs) on a polydimethylsiloxane substrate. The biofuel cell investigated consists of a porous carbon anode (area of 30 mm 2 ) modified by glucose oxidase and ferrocene, and a cathode (area of 30 mm 2 ) modified by bilirubin oxidase. The anode and the cathode were connected with the MWCNT wirings. The maximum power of 0.31 μW at 76.6 mV, which corresponds to a power density of 1.04 μW/cm 2 , was realized by immersing the biofuel cell in a phosphate buffer solution with a glucose concentration of 100 mM, at room temperature. (paper)

  18. Pre-patterned ZnO nanoribbons on soft substrates for stretchable energy harvesting applications

    Science.gov (United States)

    Ma, Teng; Wang, Yong; Tang, Rui; Yu, Hongyu; Jiang, Hanqing

    2013-05-01

    Three pre-patterned ZnO nanoribbons in different configurations were studied in this paper, including (a) straight ZnO nanoribbons uniformly bonded on soft substrates that form sinusoidal buckles, (b) straight ZnO nanoribbons selectively bonded on soft substrates that form pop-up buckles, and (c) serpentine ZnO nanoribbons bonded on soft substrates via anchors. The nonlinear dynamics and random analysis were conducted to obtain the fundamental frequencies and to evaluate their performance in energy harvesting applications. We found that pop-up buckles and overhanging serpentine structures are suitable for audio frequency energy harvesting applications. Remarkably, almost unchanged fundamental natural frequency upon strain is achieved by properly patterning ZnO nanoribbons, which initiates a new and exciting direction of stretchable energy harvesting using nano-scale materials in audio frequency range.

  19. Ultra-Stretchable Ionic Nanocomposites: From Dynamic Bonding to Multi-Responsive Behavior

    KAUST Repository

    Odent, Jeremy

    2017-06-12

    Although multi-responsive materials have the potential to revolutionize a wide spectrum of technologies, the design of systems that combine a range of responses to a variety of different external changes without the associated property trade-offs has remained elusive. We herein demonstrate a new family of multi-responsive nanocomposites that leverage the dynamic and reversible nature of electrostatic interactions present in ionic systems with the reinforcement ability of nanoparticles in nanocomposites. This new design leads to a unique property profile that combines simultaneous improvements in stiffness, toughness and extensibility. In addition to their exceptional stretchability, the new, ionic nanocomposites exhibit unique strain-dependent behavior (i.e. the deformation increases with increasing strain rate) and return to normal state after deformation including shape-memory and scratching recovery.

  20. Highly Sensitive and Stretchable Strain Sensor Based on Ag@CNTs.

    Science.gov (United States)

    Zhang, Qiang; Liu, Lihua; Zhao, Dong; Duan, Qianqian; Ji, Jianlong; Jian, Aoqun; Zhang, Wendong; Sang, Shengbo

    2017-12-04

    Due to the rapid development and superb performance of electronic skin, we propose a highly sensitive and stretchable temperature and strain sensor. Silver nanoparticles coated carbon nanowires (Ag@CNT) nanomaterials with different Ag concentrations were synthesized. After the morphology and components of the nanomaterials were demonstrated, the sensors composed of Polydimethylsiloxane (PDMS) and CNTs or Ag@CNTs were prepared via a simple template method. Then, the electronic properties and piezoresistive effects of the sensors were tested. Characterization results present excellent performance of the sensors for the highest gauge factor (GF) of the linear region between 0-17.3% of the sensor with Ag@CNTs1 was 137.6, the sensor with Ag@CNTs2 under the strain in the range of 0-54.8% exhibiting a perfect linearity and the GF of the sensor with Ag@CNTs2 was 14.9.

  1. Ultra-Stretchable Ionic Nanocomposites: From Dynamic Bonding to Multi-Responsive Behavior

    KAUST Repository

    Odent, Jeremy; Raquez, Jean-Marie; Dubois, Philippe; Giannelis, Emmanuel P.

    2017-01-01

    Although multi-responsive materials have the potential to revolutionize a wide spectrum of technologies, the design of systems that combine a range of responses to a variety of different external changes without the associated property trade-offs has remained elusive. We herein demonstrate a new family of multi-responsive nanocomposites that leverage the dynamic and reversible nature of electrostatic interactions present in ionic systems with the reinforcement ability of nanoparticles in nanocomposites. This new design leads to a unique property profile that combines simultaneous improvements in stiffness, toughness and extensibility. In addition to their exceptional stretchability, the new, ionic nanocomposites exhibit unique strain-dependent behavior (i.e. the deformation increases with increasing strain rate) and return to normal state after deformation including shape-memory and scratching recovery.

  2. The cross waveguide grating: proposal, theory and applications.

    Science.gov (United States)

    Muñoz, Pascual; Pastor, Daniel; Capmany, José

    2005-04-18

    In this paper a novel grating-like integrated optics device is proposed, the Cross Waveguide Grating (XWG). The device is based upon a modified configuration of a traditional Arrayed Waveguide Grating (AWG). The Arrayed Waveguides part is changed, as detailed along this document, giving the device both the ability of multi/demultiplexing and power splitting/coupling. Design examples and transfer function simulations show good agreement with the presented theory. Finally, some of the envisaged applications are outlined.

  3. Observation of narrowband intrinsic spectra of Brillouin dynamic gratings.

    Science.gov (United States)

    Song, Kwang Yong; Yoon, Hyuk Jin

    2010-09-01

    We experimentally demonstrate that the reflection spectrum of a Brillouin dynamic grating in a polarization-maintaining fiber can be much narrower than the intrinsic linewidth of the stimulated Brillouin scattering, matching well with the theory of a fiber Bragg grating in terms of the linewidth and the reflectivity. A 3 dB bandwidth as narrow as 10.5 MHz is observed with the Brillouin dynamic grating generated in a 9 m uniform fiber.

  4. Wearable multifunctional sensors using printed stretchable conductors made of silver nanowires

    Science.gov (United States)

    Yao, Shanshan; Zhu, Yong

    2014-01-01

    Considerable efforts have been made to achieve highly sensitive and wearable sensors that can simultaneously detect multiple stimuli such as stretch, pressure, temperature or touch. Here we develop highly stretchable multifunctional sensors that can detect strain (up to 50%), pressure (up to ~1.2 MPa) and finger touch with high sensitivity, fast response time (~40 ms) and good pressure mapping function. The reported sensors utilize the capacitive sensing mechanism, where silver nanowires are used as electrodes (conductors) and Ecoflex is used as a dielectric. The silver nanowire electrodes are screen printed. Our sensors have been demonstrated for several wearable applications including monitoring thumb movement, sensing the strain of the knee joint in patellar reflex (knee-jerk) and other human motions such as walking, running and jumping from squatting, illustrating the potential utilities of such sensors in robotic systems, prosthetics, healthcare and flexible touch panels.Considerable efforts have been made to achieve highly sensitive and wearable sensors that can simultaneously detect multiple stimuli such as stretch, pressure, temperature or touch. Here we develop highly stretchable multifunctional sensors that can detect strain (up to 50%), pressure (up to ~1.2 MPa) and finger touch with high sensitivity, fast response time (~40 ms) and good pressure mapping function. The reported sensors utilize the capacitive sensing mechanism, where silver nanowires are used as electrodes (conductors) and Ecoflex is used as a dielectric. The silver nanowire electrodes are screen printed. Our sensors have been demonstrated for several wearable applications including monitoring thumb movement, sensing the strain of the knee joint in patellar reflex (knee-jerk) and other human motions such as walking, running and jumping from squatting, illustrating the potential utilities of such sensors in robotic systems, prosthetics, healthcare and flexible touch panels. Electronic

  5. Exploiting Stretchable Metallic Springs as Compliant Electrodes for Cylindrical Dielectric Elastomer Actuators (DEAs

    Directory of Open Access Journals (Sweden)

    Chien-Hao Liu

    2017-11-01

    Full Text Available In recent years, dielectric elastomer actuators (DEAs have been widely used in soft robots and artificial bio-medical applications. Most DEAs are composed of a thin dielectric elastomer layer sandwiched between two compliant electrodes. DEAs vary in their design to provide bending, torsional, and stretch/contraction motions under the application of high external voltages. Most compliant electrodes are made of carbon powders or thin metallic films. In situations involving large deformations or improper fabrication, the electrodes are susceptible to breakage and increased resistivity. The worst cases result in a loss of conductivity and functional failure. In this study, we developed a method by which to exploit stretchable metallic springs as compliant electrodes for cylindrical DEAs. This design was inspired by the extensibility of mechanical springs. The main advantage of this approach is the fact that the metallic spring-like compliant electrodes remain conductive and do not increase the stiffness as the tube-like DEAs elongate in the axial direction. This can be attributed to a reduction in thickness in the radial direction. The proposed cylindrical structure is composed of highly-stretchable VHB 4905 film folded within a hollow tube and then sandwiched between copper springs (inside and outside to allow for stretching and contraction in the axial direction under the application of high DC voltages. We fabricated a prototype and evaluated the mechanical and electromechanical properties of the device experimentally using a high-voltage source of 9.9 kV. This device demonstrated a non-linear increase in axial stretching with an increase in applied voltage, reaching a maximum extension of 0.63 mm (axial strain of 2.35% at applied voltage of 9.9 kV. Further miniaturization and the incorporation of compressive springs are expected to allow the implementation of the proposed method in soft micro-robots and bio-mimetic applications.

  6. Adhesion enhancement by a dielectric barrier discharge of PDMS used for flexible and stretchable electronics

    International Nuclear Information System (INIS)

    Morent, R; Geyter, N De; Axisa, F; Smet, N de; Gengembre, L; Leersnyder, E De; Leys, C; Vanfleteren, J; Rymarczyk-Machal, M; Schacht, E; Payen, E

    2007-01-01

    Currently, there is a strong tendency to replace rigid electronic assemblies by mechanically flexible and stretchable equivalents. This emerging technology can be applied for biomedical electronics, such as implantable devices and electronics on skin. In the first step of the production process of stretchable electronics, electronic interconnections and components are encapsulated into a thin layer of polydimethylsiloxane (PDMS). Afterwards, the electronic structures are completely embedded by placing another PDMS layer on top. It is very important that the metals inside the electronic circuit do not leak out in order to obtain a highly biocompatible system. Therefore, an excellent adhesion between the 2 PDMS layers is of great importance. However, PDMS has a very low surface energy, resulting in poor adhesion properties. Therefore, in this paper, PDMS films are plasma treated with a dielectric barrier discharge (DBD) operating in air at medium pressure (5.0 kPa). Contact angle and XPS measurements reveal that plasma treatment increases the hydrophilicity of the PDMS films due to the incorporation of silanol groups at the expense of methyl groups. T-peel tests show that plasma treatment rapidly imparts adhesion enhancement, but only when both PDMS layers are plasma treated. Results also reveal that it is very important to bond the plasma-treated PDMS films immediately after treatment. In this case, an excellent adhesion is maintained several days after treatment. The ageing behaviour of the plasma-treated PDMS films is also studied in detail: contact angle measurements show that the contact angle increases during storage in air and angle-resolved XPS reveals that this hydrophobic recovery is due to the migration of low molar mass PDMS species to the surface

  7. High-mechanical-strength single-pulse draw tower gratings

    Science.gov (United States)

    Rothhardt, Manfred W.; Chojetzki, Christoph; Mueller, Hans Rainer

    2004-11-01

    The inscription of fiber Bragg gratings during the drawing process is a very useful method to realize sensor arrays with high numbers of gratings and excellent mechanical strength and also type II gratings with high temperature stability. Results of single pulse grating arrays with numbers up to 100 and definite wavelengths and positions for sensor applications were achieved at 1550 nm and 830 nm using new photosensitive fibers developed in IPHT. Single pulse type I gratings at 1550 nm with more than 30% reflectivity were shown first time to our knowledge. The mechanical strength of this fiber with an Ormocer coating with those single pulse gratings is the same like standard telecom fibers. Weibull plots of fiber tests will be shown. At 830 nm we reached more than 10% reflectivity with single pulse writing during the fiber drawing in photosensitive fibers with less than 16 dB/km transmission loss. These gratings are useful for stress and vibration sensing applications. Type II gratings with reflectivity near 100% and smooth spectral shape and spectral width of about 1 nm are temperature stable up to 1200 K for short time. They are also realized in the fiber drawing process. These gratings are useful for temperature sensor applications.

  8. Bragg Fibers with Soliton-like Grating Profiles

    Directory of Open Access Journals (Sweden)

    Bugaychuk S.

    2016-01-01

    Full Text Available Nonlinear dynamical system corresponding to the optical holography in a nonlocal nonlinear medium with dissipation contains stable localized spatio-temporal states, namely the grid dissipative solitons. These solitons display a non-uniform profile of the grating amplitude, which has the form of the dark soliton in the reflection geometry. The transformation of the grating amplitude gives rise many new atypical effects for the beams diffracted on such grating, and they are very suitable for the fiber Brass gratings. The damped nonlinear Schrodinger equation is derived that describes the properties of the grid dissipative soliton.

  9. Spherical grating based x-ray Talbot interferometry

    Energy Technology Data Exchange (ETDEWEB)

    Cong, Wenxiang, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu; Xi, Yan, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu; Wang, Ge, E-mail: congw@rpi.edu, E-mail: xiy2@rpi.edu, E-mail: wangg6@rpi.edu [Biomedical Imaging Center, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

    2015-11-15

    Purpose: Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme for a wider range of preclinical and clinical applications. Methods: A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Results: Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh–Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. Conclusions: X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and

  10. Spherical grating based x-ray Talbot interferometry

    International Nuclear Information System (INIS)

    Cong, Wenxiang; Xi, Yan; Wang, Ge

    2015-01-01

    Purpose: Grating interferometry is a state-of-the-art x-ray imaging approach, which can acquire information on x-ray attenuation, phase shift, and small-angle scattering simultaneously. Phase-contrast imaging and dark-field imaging are very sensitive to microstructural variation and offers superior contrast resolution for biological soft tissues. However, a common x-ray tube is a point-like source. As a result, the popular planar grating imaging configuration seriously restricts the flux of photons and decreases the visibility of signals, yielding a limited field of view. The purpose of this study is to extend the planar x-ray grating imaging theory and methods to a spherical grating scheme for a wider range of preclinical and clinical applications. Methods: A spherical grating matches the wave front of a point x-ray source very well, allowing the perpendicular incidence of x-rays on the grating to achieve a higher visibility over a larger field of view than the planer grating counterpart. A theoretical analysis of the Talbot effect for spherical grating imaging is proposed to establish a basic foundation for x-ray spherical gratings interferometry. An efficient method of spherical grating imaging is also presented to extract attenuation, differential phase, and dark-field images in the x-ray spherical grating interferometer. Results: Talbot self-imaging with spherical gratings is analyzed based on the Rayleigh–Sommerfeld diffraction formula, featuring a periodic angular distribution in a polar coordinate system. The Talbot distance is derived to reveal the Talbot self-imaging pattern. Numerical simulation results show the self-imaging phenomenon of a spherical grating interferometer, which is in agreement with the theoretical prediction. Conclusions: X-ray Talbot interferometry with spherical gratings has a significant practical promise. Relative to planar grating imaging, spherical grating based x-ray Talbot interferometry has a larger field of view and

  11. Fiber facet gratings for high power fiber lasers

    Science.gov (United States)

    Vanek, Martin; Vanis, Jan; Baravets, Yauhen; Todorov, Filip; Ctyroky, Jiri; Honzatko, Pavel

    2017-12-01

    We numerically investigated the properties of diffraction gratings designated for fabrication on the facet of an optical fiber. The gratings are intended to be used in high-power fiber lasers as mirrors either with a low or high reflectivity. The modal reflectance of low reflectivity polarizing grating has a value close to 3% for TE mode while it is significantly suppressed for TM mode. Such a grating can be fabricated on laser output fiber facet. The polarizing grating with high modal reflectance is designed as a leaky-mode resonant diffraction grating. The grating can be etched in a thin layer of high index dielectric which is sputtered on fiber facet. We used refractive index of Ta2O5 for such a layer. We found that modal reflectance can be close to 0.95 for TE polarization and polarization extinction ratio achieves 18 dB. Rigorous coupled wave analysis was used for fast optimization of grating parameters while aperiodic rigorous coupled wave analysis, Fourier modal method and finite difference time domain method were compared and used to compute modal reflectance of designed gratings.

  12. Critical Role of Diels-Adler Adducts to Realise Stretchable Transparent Electrodes Based on Silver Nanowires and Silicone Elastomer

    Science.gov (United States)

    Heo, Gaeun; Pyo, Kyoung-Hee; Lee, Da Hee; Kim, Youngmin; Kim, Jong-Woong

    2016-05-01

    This paper presents the successful fabrication of a transparent electrode comprising a sandwich structure of silicone/Ag nanowires (AgNWs)/silicone equipped with Diels-Alder (DA) adducts as crosslinkers to realise highly stable stretchability. Because of the reversible DA reaction, the crosslinked silicone successfully bonds with the silicone overcoat, which should completely seal the electrode. Thus, any surrounding liquid cannot leak through the interfaces among the constituents. Furthermore, the nanowires are protected by the silicone cover when they are stressed by mechanical loads such as bending, folding, and stretching. After delicate optimisation of the layered silicone/AgNW/silicone sandwich structure, a stretchable transparent electrode which can withstand 1000 cycles of 50% stretching-releasing with an exceptionally high stability and reversibility was fabricated. This structure can be used as a transparent strain sensor; it possesses a strong piezoresistivity with a gauge factor greater than 11.

  13. Optical temperature sensing on flexible polymer foils

    Science.gov (United States)

    Sherman, Stanislav; Xiao, Yanfen; Hofmann, Meike; Schmidt, Thomas; Gleissner, Uwe; Zappe, Hans

    2016-04-01

    In contrast to established semiconductor waveguide-based or glass fiber-based integrated optical sensors, polymerbased optical systems offer tunable material properties, such as refractive index or viscosity, and thus provide additional degrees of freedom for sensor design and fabrication. Of particular interest in sensing applications are fully-integrated optical waveguide-based temperature sensors. These typically rely on Bragg gratings which induce a periodic refractive index variation in the waveguide so that a resonant wavelength of the structure is reflected.1,2 With broad-band excitation, a dip in the spectral output of the waveguide is thus generated at a precisely-defined wavelength. This resonant wavelength depends on the refractive index of the waveguide and the grating period, yet both of these quantities are temperature dependent by means of the thermo-optic effect (change in refractive index with temperature) and thermal expansion (change of the grating period with temperature). We show the design and fabrication of polymer waveguide-integrated temperature sensors based on Bragggratings, fabricated by replication technology on flexible PMMA foil substrates. The 175 μm thick foil serves as lower cladding for a polymeric waveguide fabricated from a custom-made UV-crosslinkable co-monomer composition. The fabrication of the grating structure includes a second replication step into a separate PMMA-foil. The dimensions of the Bragg-gratings are determined by simulations to set the bias point into the near infrared wavelength range, which allows Si-based detectors to be used. We present design considerations and performance data for the developed structures. The resulting sensor's signal is linear to temperature changes and shows a sensitivity of -306 nm/K, allowing high resolution temperature measurements.

  14. Highly Stretchable Potentiometric pH Sensor Fabricated via Laser Carbonization and Machining of Carbon-Polyaniline Composite.

    Science.gov (United States)

    Rahimi, Rahim; Ochoa, Manuel; Tamayol, Ali; Khalili, Shahla; Khademhosseini, Ali; Ziaie, Babak

    2017-03-15

    The development of stretchable sensors has recently attracted considerable attention. These sensors have been used in wearable and robotics applications, such as personalized health-monitoring, motion detection, and human-machine interfaces. Herein, we report on a highly stretchable electrochemical pH sensor for wearable point-of-care applications that consists of a pH-sensitive working electrode and a liquid-junction-free reference electrode, in which the stretchable conductive interconnections are fabricated by laser carbonizing and micromachining of a polyimide sheet bonded to an Ecoflex substrate. This method produces highly porous carbonized 2D serpentine traces that are subsequently permeated with polyaniline (PANI) as the conductive filler, binding material, and pH-sensitive membrane. The experimental and simulation results demonstrate that the stretchable serpentine PANI/C-PI interconnections with an optimal trace width of 0.3 mm can withstand elongations of up to 135% and are robust to more than 12 000 stretch-and-release cycles at 20% strain without noticeable change in the resistance. The pH sensor displays a linear sensitivity of -53 mV/pH (r 2 = 0.976) with stable performance in the physiological range of pH 4-10. The sensor shows excellent stability to applied longitudinal and transverse strains up to 100% in different pH buffer solutions with a minimal deviation of less than ±4 mV. The material biocompatibility is confirmed with NIH 3T3 fibroblast cells via PrestoBlue assays.

  15. A Flexible, Stretchable and Shape-Adaptive Approach for Versatile Energy Conversion and Self-Powered Biomedical Monitoring

    KAUST Repository

    Yang, Po Kang

    2015-05-15

    A flexible triboelectric nanogenerator (FTENG) based on wavy-structured Kapton film and a serpentine electrode on stretchable substrates is presented. The as-fabricated FTENG is capable of harvesting ambient mechanical energy via both compressive and stretching modes. Moreover, the FTENG can be a bendable power source to work on curved surfaces; it can also be adaptively attached onto human skin for monitoring gentle body motions. © 2015 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. High-accuracy measurement and compensation of grating line-density error in a tiled-grating compressor

    Science.gov (United States)

    Zhao, Dan; Wang, Xiao; Mu, Jie; Li, Zhilin; Zuo, Yanlei; Zhou, Song; Zhou, Kainan; Zeng, Xiaoming; Su, Jingqin; Zhu, Qihua

    2017-02-01

    The grating tiling technology is one of the most effective means to increase the aperture of the gratings. The line-density error (LDE) between sub-gratings will degrade the performance of the tiling gratings, high accuracy measurement and compensation of the LDE are of significance to improve the output pulses characteristics of the tiled-grating compressor. In this paper, the influence of LDE on the output pulses of the tiled-grating compressor is quantitatively analyzed by means of numerical simulation, the output beams drift and output pulses broadening resulting from the LDE are presented. Based on the numerical results we propose a compensation method to reduce the degradations of the tiled grating compressor by applying angular tilt error and longitudinal piston error at the same time. Moreover, a monitoring system is setup to measure the LDE between sub-gratings accurately and the dispersion variation due to the LDE is also demonstrated based on spatial-spectral interference. In this way, we can realize high-accuracy measurement and compensation of the LDE, and this would provide an efficient way to guide the adjustment of the tiling gratings.

  17. Streaked, x-ray-transmission-grating spectrometer

    International Nuclear Information System (INIS)

    Ceglio, N.M.; Roth, M.; Hawryluk, A.M.

    1981-08-01

    A free standing x-ray transmission grating has been coupled with a soft x-ray streak camera to produce a time resolved x-ray spectrometer. The instrument has a temporal resolution of approx. 20 psec, is capable of covering a broad spectral range, 2 to 120 A, has high sensitivity, and is simple to use requiring no complex alignment procedure. In recent laser fusion experiments the spectrometer successfully recorded time resolved spectra over the range 10 to 120 A with a spectral resolving power, lambda/Δlambda of 4 to 50, limited primarily by source size and collimation effects

  18. Stretchable Complementary Split Ring Resonator (CSRR-Based Radio Frequency (RF Sensor for Strain Direction and Level Detection

    Directory of Open Access Journals (Sweden)

    Seunghyun Eom

    2016-10-01

    Full Text Available In this paper, we proposed a stretchable radio frequency (RF sensor to detect strain direction and level. The stretchable sensor is composed of two complementary split ring resonators (CSRR with microfluidic channels. In order to achieve stretchability, liquid metal (eutectic gallium-indium, EGaIn and Ecoflex substrate are used. Microfluidic channels are built by Ecoflex elastomer and microfluidic channel frames. A three-dimensional (3D printer is used for fabrication of microfluidic channel frames. Two CSRR resonators are designed to resonate 2.03 GHz and 3.68 GHz. When the proposed sensor is stretched from 0 to 8 mm along the +x direction, the resonant frequency is shifted from 3.68 GHz to 3.13 GHz. When the proposed sensor is stretched from 0 to 8 mm along the −x direction, the resonant frequency is shifted from 2.03 GHz to 1.78 GHz. Therefore, we can detect stretched length and direction from independent variation of two resonant frequencies.

  19. Strain-dependent characterization of electrode and polymer network of electrically activated polymer actuators

    Science.gov (United States)

    Töpper, Tino; Osmani, Bekim; Weiss, Florian M.; Winterhalter, Carla; Wohlfender, Fabian; Leung, Vanessa; Müller, Bert

    2015-04-01

    Fecal incontinence describes the involuntary loss of bowel content and affects about 45 % of retirement home residents and overall more than 12 % of the adult population. Artificial sphincter implants for treating incontinence are currently based on mechanical systems with failure rates resulting in revision after three to five years. To overcome this drawback, artificial muscle sphincters based on bio-mimetic electro-active polymer (EAP) actuators are under development. Such implants require polymer films that are nanometer-thin, allowing actuation below 24 V, and electrodes that are stretchable, remaining conductive at strains of about 10 %. Strain-dependent resistivity measurements reveal an enhanced conductivity of 10 nm compared to 30 nm sputtered Au on silicone for strains higher than 5 %. Thus, strain-dependent morphology characterization with optical microscopy and atomic force microscopy could demonstrate these phenomena. Cantilever bending measurements are utilized to determine elastic/viscoelastic properties of the EAP films as well as their long-term actuation behavior. Controlling these properties enables the adjustment of growth parameters of nanometer-thin EAP actuators.

  20. Polynomial modal analysis of lamellar diffraction gratings in conical mounting.

    Science.gov (United States)

    Randriamihaja, Manjakavola Honore; Granet, Gérard; Edee, Kofi; Raniriharinosy, Karyl

    2016-09-01

    An efficient numerical modal method for modeling a lamellar grating in conical mounting is presented. Within each region of the grating, the electromagnetic field is expanded onto Legendre polynomials, which allows us to enforce in an exact manner the boundary conditions that determine the eigensolutions. Our code is successfully validated by comparison with results obtained with the analytical modal method.