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Sample records for polyaniline composite films

  1. Preparation and characterization of polyaniline-palladium composite films

    SciTech Connect

    Li, H.S.; Josowicz, M.; Baer, D.R.; Engelhard, M.H.; Janata, J.

    1995-03-01

    Palladium is a preeminent material for the preparation of sensors for hydrogen and hydrogen-evolving compounds. Conducting polyaniline can be chemically or electrochemically functionalized by the incorporation of palladium clusters. Different interfaces in a three-dimensional matrix for hydrogen adsorption, desorption, and evolution were synthesized and characterized. Dispersions of palladium clusters in the polymer film were formed by various preparation routes, which can be classified as one or two-step processes. In the one-step process, the composite material was obtained during the electrosynthesis of polyaniline film. In the two-step processes, Pd aggregated into the polyaniline modified electrode. Electrochemical examination, x-ray photoelectron spectroscopy, and Auger electron spectroscopy have been employed to characterize the composite materials in view of the hydrogen sorption and evolution as well as the binding energy stale and the spatial distribution of the palladium clusters in polyaniline film.

  2. Characterization of polyaniline / metal oxide composite films for sensing ammonia

    NASA Astrophysics Data System (ADS)

    Patrick, Eddie

    Sensors are attractive because of their affordable price, compact size, the opportunity that they provide in determining various analytes (gases) under special conditions both in the laboratory and in the field. The increased concern about environmental protection has led to continuous expansion in sensor development. Ammonia is amongst a group of very toxic gases that can cause harm to our body. It is important to be able to monitor and detect this gas in many applications. The objective of the research is to discover a better way to fabricate an ammonia sensor. This paper describes and characterizes the gas sensing properties of a PANI (polyaniline)/Co3O4 composite thin film NH3 sensor at room temperature. Additional research is done to compare and contrast how the polymer (polyaniline) reacts with other metal oxides (PANI/V2O5 and PANI/Nb 2O5) at different temperatures. The results in the present work demonstrate that the PANI/Co3O4 composite sample devices produced optimum ammonia gas sensing characteristics at room temperature.

  3. Electrochemical preparation of Photosystem I-polyaniline composite films for biohybrid solar energy conversion.

    PubMed

    Gizzie, Evan A; LeBlanc, Gabriel; Jennings, G Kane; Cliffel, David E

    2015-05-13

    In this work, we report for the first time the entrapment of the biomolecular supercomplex Photosystem I (PSI) within a conductive polymer network of polyaniline via electrochemical copolymerization. Composite polymer-protein films were prepared on gold electrodes through potentiostatic electropolymerization from a single aqueous solution containing both aniline and PSI. This study demonstrates the controllable integration of large membrane proteins into rapidly prepared composite films, the entrapment of such proteins was observed through photoelectrochemical analysis. PSI's unique function as a highly efficient biomolecular photodiode generated a significant enhancement in photocurrent generation for the PSI-loaded polyaniline films, compared to pristine polyaniline films, and dropcast PSI films. A comprehensive study was then performed to separately evaluate film thickness and PSI concentration in the initial polymerization solution and their effects on the net photocurrent of this novel material. The best performing composite films were prepared with 0.1 μM PSI in the polymerization solution and deposited to a film thickness of 185 nm, resulting in an average photocurrent density of 5.7 μA cm(-2) with an efficiency of 0.005%. This photocurrent output represents an enhancement greater than 2-fold over bare polyaniline films and 200-fold over a traditional PSI multilayer film of comparable thickness.

  4. Fabrication of graphene/polyaniline composite multilayer films by electrostatic layer-by-layer assembly

    SciTech Connect

    Cong, Jiaojiao; Chen, Yuze; Luo, Jing Liu, Xiaoya

    2014-10-15

    A novel graphene/polyaniline composite multilayer film was fabricated by electrostatic interactions induced layer-by-layer self-assembly technique, using water dispersible and negatively charged chemically converted graphene (CCG) and positively charged polyaniline (PANI) as building blocks. CCG was achieved through partly reduced graphene oxide, which remained carboxyl group on its surface. The remaining carboxyl groups not only retain the dispersibility of CCG, but also allow the growth of the multilayer films via electrostatic interactions between graphene and PANI. The structure and morphology of the obtained CCG/PANI multilayer film are characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, Ultraviolet–visible absorption spectrum (UV–vis), scanning electron microscopy (SEM), Raman spectroscopy and X-Ray Diffraction (XRD). The electrochemical properties of the resulting film are studied using cyclic voltammetry (CV), which showed that the resulting CCG/PANI multilayer film kept electroactivity in neutral solution and showed outstanding cyclic stability up to 100 cycles. Furthermore, the composite film exhibited good electrocatalytic ability toward ascorbic acid (AA) with a linear response from 1×10{sup −4} to 1.2×10{sup −3} M with the detect limit of 5×10{sup −6} M. This study provides a facile and effective strategy to fabricate graphene/PANI nanocomposite film with good electrochemical property, which may find potential applications in electronic devices such as electrochemical sensor. - Graphical abstract: A novel graphene/polyaniline (CCG/PANI) film was prepared by layer-by-layer assembly. - Highlights: • A novel graphene/polyaniline (CCG/PANI) film was prepared by layer-by-layer assembly. • The water dispersible and negatively charged graphene (CCG) was used as building block. • CCG was achieved through partly reduced graphene oxide with carboxyl group on its surface. • CCG/PANI film kept

  5. Graphene/polyaniline woven fabric composite films as flexible supercapacitor electrodes.

    PubMed

    Zang, Xiaobei; Li, Xiao; Zhu, Miao; Li, Xinming; Zhen, Zhen; He, Yijia; Wang, Kunlin; Wei, Jinquan; Kang, Feiyu; Zhu, Hongwei

    2015-04-28

    We report the design and preparation of graphene and polyaniline (PANI) woven-fabric composite films by in situ electropolymerization. The introduction of PANI greatly improves the electrochemical properties of solid-state supercapacitors which possess capacitances as high as 23 mF cm(-2), and exhibit excellent cycling stability with ∼ 100% capacitance retention after 2000 cycles. The devices have displayed superior flexibility with improved areal specific capacitances to 118% during deformation.

  6. Fabrication of graphene/polyaniline composite multilayer films by electrostatic layer-by-layer assembly

    NASA Astrophysics Data System (ADS)

    Cong, Jiaojiao; Chen, Yuze; Luo, Jing; Liu, Xiaoya

    2014-10-01

    A novel graphene/polyaniline composite multilayer film was fabricated by electrostatic interactions induced layer-by-layer self-assembly technique, using water dispersible and negatively charged chemically converted graphene (CCG) and positively charged polyaniline (PANI) as building blocks. CCG was achieved through partly reduced graphene oxide, which remained carboxyl group on its surface. The remaining carboxyl groups not only retain the dispersibility of CCG, but also allow the growth of the multilayer films via electrostatic interactions between graphene and PANI. The structure and morphology of the obtained CCG/PANI multilayer film are characterized by attenuated total reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, Ultraviolet-visible absorption spectrum (UV-vis), scanning electron microscopy (SEM), Raman spectroscopy and X-Ray Diffraction (XRD). The electrochemical properties of the resulting film are studied using cyclic voltammetry (CV), which showed that the resulting CCG/PANI multilayer film kept electroactivity in neutral solution and showed outstanding cyclic stability up to 100 cycles. Furthermore, the composite film exhibited good electrocatalytic ability toward ascorbic acid (AA) with a linear response from 1×10-4 to 1.2×10-3 M with the detect limit of 5×10-6 M. This study provides a facile and effective strategy to fabricate graphene/PANI nanocomposite film with good electrochemical property, which may find potential applications in electronic devices such as electrochemical sensor.

  7. Polyaniline/poly acid acrylic thin film composites: a new gamma radiation detector

    SciTech Connect

    Lima Pacheco, Ana P.; Araujo, Elmo S.; Azevedo, Walter M. de

    2003-03-15

    In this paper, we present a new and straightforward route to prepare polyaniline/poly acid acrylic (PAA) thin film composites in large areas and on almost any surface. This method was developed to improve the mechanical and adherence properties of polyaniline devices used as ionization radiation sensors. The route consists of the combination of the metal oxidant with polymer acid to form a highly homogeneous and viscous paste, which can be easily spread over any surface. In the second step, an aniline acid solution is brought in contact with the dried paste where polymerization occurs, yielding a high homogeneous and conducting polymer composite. The UV-visible absorption and infrared analysis confirm that a polyaniline/PAA complex is obtained. The four-point conductivity measurements show that the composite conductivity {rho} is the order of 5 {omega}{sup -1} cm{sup -1}. Preliminary gamma radiation interaction with the composite shows that the doped composite exhibits a linear response that can be used in the development of real-time radiation sensors for the dose range from 0 to 5000 Gy.

  8. Novel poly (vinyl butyral) (PVB)/polyaniline-cenosphere composite film for EMI shielding

    NASA Astrophysics Data System (ADS)

    Bora, Pritom J.; Shahidsha, N.; Madras, Giridhar; Kishore, Ramamurthy, Praveen C.

    2016-05-01

    in-situ synthesis of polyaniline (PANI)/fly ash cenosphere (hollow microspheres) composite was carried out under nitrogen atmosphere at -30±2 °C. Investigated electromagnetic shielding effectiveness (EMI SE) of free standing PVB/PANI-cenosphere (PVBPC) composite films prepared by solution casting indicates an ap preciable shielding. The most effective EMI SE of 30.3 dB was obtained for 197±3 µm thicker flexible film over the frequency range 8.2-12.4 GHz. Mechanistically, absorption was found to be dominant. The obtained shielding effectiveness due to absorbance (SEA) of PVBPC film is more than two times higher than PVB/PANI composite film. In the presence of hollow PANI-cenospheres in PVB matrix the time average power of incident electromagnetic wave decreases resulting in an increase of absorbance.

  9. Elaboration of m-cresol polyamide12/ polyaniline composite films for antistatic applications

    SciTech Connect

    Mezdour, D.; Tabellout, M.; Bardeau, J.-F; Sahli, S.

    2013-12-16

    The present work deals with the preparation of transparent antistatic films from an extreme dilution of an intrinsically conducting polymer (ICP) with not coloured polymers. Our approach is based on the chemical polymerization of a very thin layer of Polyaniline (PANI) around particles of an insulating polymer (PA12). Films were obtained by dissolving the synthesized core-shell particles in m-Cresol. The electric property and structure relationships were investigated by using dielectric relaxation spectroscopy, X-ray diffraction and micro-Raman spectroscopy. Composite films exhibited a well established dc conductivity over all the frequency range for 10 wt. % of PANI concentration related to the conductive properties of the PANI clusters. X-ray diffraction data show broader and lower intensity of PA12 peaks when increasing PANI content, probably due to the additional doping effect of m- cresol. The doping of PA12/PANI films with Dodecyl benzene sulfonic acid (DBSA) was unequivocally verified by Raman spectroscopy.

  10. Graphene/polyaniline woven fabric composite films as flexible supercapacitor electrodes

    NASA Astrophysics Data System (ADS)

    Zang, Xiaobei; Li, Xiao; Zhu, Miao; Li, Xinming; Zhen, Zhen; He, Yijia; Wang, Kunlin; Wei, Jinquan; Kang, Feiyu; Zhu, Hongwei

    2015-04-01

    We report the design and preparation of graphene and polyaniline (PANI) woven-fabric composite films by in situ electropolymerization. The introduction of PANI greatly improves the electrochemical properties of solid-state supercapacitors which possess capacitances as high as 23 mF cm-2, and exhibit excellent cycling stability with ~100% capacitance retention after 2000 cycles. The devices have displayed superior flexibility with improved areal specific capacitances to 118% during deformation.We report the design and preparation of graphene and polyaniline (PANI) woven-fabric composite films by in situ electropolymerization. The introduction of PANI greatly improves the electrochemical properties of solid-state supercapacitors which possess capacitances as high as 23 mF cm-2, and exhibit excellent cycling stability with ~100% capacitance retention after 2000 cycles. The devices have displayed superior flexibility with improved areal specific capacitances to 118% during deformation. Electronic supplementary information (ESI) available: SEM image, Raman spectrum and electrochemical characterizations. See DOI: 10.1039/c5nr00584a

  11. Preparation, characterization and electrochromic properties of composite thin films incorporation of polyaniline

    NASA Astrophysics Data System (ADS)

    Farasat, Mahshid; Golzan, M. Maqsood; Farhadi, Khalil; Shojaei, S. H. Reza; Gheisvandi, Sorayya

    2016-05-01

    Two different electrochromic composite films consisting of aniline/sodium molybdate (S1) and aniline/ferric nitrate (S2) were obtained by electrochemical polymerization method on indium tin oxide (ITO) coated glass substrates in oxalic acid (H2C2O4ṡ2H2O) aqueous solution. The electrochromic properties of the resulting thin films were investigated by spectroelectrochemical measurement and cyclic voltammetry (CV). Under a square electrical potential, they show capacitive current characteristic and represent electrochromic performance, with maximum optical attenuations (ΔT%) of 30.8% at 355nm and 28.3% at 400nm for aniline/ferric nitrate and aniline/sodium molybdate thin films, respectively. Optical behavior of thin films was examined by UV-Vis spectrophotometry technique. The doped films indicated multiple color changes (yellow; green; and bluish green). The spectra also showed that produced layers have high absorption of UV radiation with respect to pure polyaniline (PANI) films. The optical band gap energy of PANI film decreased by dopant injection. Due to their decent transparency and electrochromic behavior, they are promising materials for electrochromic devices.

  12. Lightweight polyaniline-cobalt coated fly ash cenosphere composite film for electromagnetic interference shielding

    NASA Astrophysics Data System (ADS)

    Bora, Pritom J.; Vinoy, K. J.; Ramamurthy, Praveen C.; Kishore; Madras, Giridhar

    2016-09-01

    Thermal power plant's solid environmental waste fly ash cenosphere (FAC) is cobalt coated chemically and functionalized by in situ synthesis of polyaniline (PANI) under nitrogen atmosphere at -30 ± 2 °C and characterized by various techniques. The electromagnetic interference shielding effectiveness (EMI SE) of free standing PANI/Co-FAC (PCC) films prepared by solution casting indicates an appreciable shielding. The most effective average EMI SE of ~ 30 dB was obtained for 89 ± 3 μm thicker flexible film over the frequency range of 12.4-18 GHz (Ku-band). Mechanistically, EMI shielding due to absorption was found to be dominant. The obtained shielding effectiveness due to absorbance ( SE A ) of PCC film is nearly two times higher than PC film. The microwave conductivity (σ) of PCC film (157-184 Sm-1) is much higher than PC film (118-142 Sm-1). Moreover, the high EM attenuation constant ( α) value of PCC film indicates excellent suitability of EMI shielding due to absorption.

  13. Lightweight polyaniline-cobalt coated fly ash cenosphere composite film for electromagnetic interference shielding

    NASA Astrophysics Data System (ADS)

    Bora, Pritom J.; Vinoy, K. J.; Ramamurthy, Praveen C.; Kishore; Madras, Giridhar

    2016-07-01

    Thermal power plant's solid environmental waste fly ash cenosphere (FAC) is cobalt coated chemically and functionalized by in situ synthesis of polyaniline (PANI) under nitrogen atmosphere at -30 ± 2 °C and characterized by various techniques. The electromagnetic interference shielding effectiveness (EMI SE) of free standing PANI/Co-FAC (PCC) films prepared by solution casting indicates an appreciable shielding. The most effective average EMI SE of ~ 30 dB was obtained for 89 ± 3 µm thicker flexible film over the frequency range of 12.4-18 GHz (Ku-band). Mechanistically, EMI shielding due to absorption was found to be dominant. The obtained shielding effectiveness due to absorbance (SE A) of PCC film is nearly two times higher than PC film. The microwave conductivity (s) of PCC film (157-184 Sm-1) is much higher than PC film (118-142 Sm-1). Moreover, the high EM attenuation constant (α) value of PCC film indicates excellent suitability of EMI shielding due to absorption.

  14. Nanostructured metal-polyaniline composites

    DOEpatents

    Wang, Hsing-Lin; Li, Wenguang; Bailey, James A.; Gao, Yuan

    2010-08-31

    Metal-polyaniline (PANI) composites are provided together with a process of preparing such composites by an electrodeless process. The metal of the composite can have nanoscale structural features and the composites can be used in applications such as catalysis for hydrogenation reactions and for analytical detection methods employing SERS.

  15. Magnetic and electromagnetic properties of Pr doped strontium ferrite/polyaniline composite film

    NASA Astrophysics Data System (ADS)

    Huang, Ying; Li, Yuqing; Wang, Yan

    2014-11-01

    This paper reported three acid (including hydrochloric acid HCl, p-toluenesulfonic acid PTS and D-camphor-10-acid CSA) doped SrPr0.2Fe11.8O19/PANI composite film and the HCl-PANI film prepared by a sol-gel method and in-situ oxidative polymerization. The characteristics of the film phase structure, surface morphology, conductivity and magnetic and electromagnetic properties were studied by using XRD, XPS, FESEM, four-probe tester, VSM and Vector Network Analyzer. The resistivity of organic acid doped composite films is higher than that of the HCl doped one. The saturation and remanent magnetization of PTS and HCl doped composite films are greater than the CSA-doped one; however, the coercivity of the three acid doped composite films is basically 5546 Oe. The saturation magnetization, remanent magnetization and coercivity of SrPr0.2Fe11.8O19 film are greater than those of the SrPr0.2Fe11.8O19-PANI composite film. In the frequency range of 8-12 GHz, the dielectric loss of HCl-PANI film is the maximum, and the dielectric loss of SrPr0.2Fe11.8O19 film is the minimum; the magnetic loss of the four films is in descending order as SrPr0.2Fe11.8O19 film, PrSrM/(HCl-PANI) composite film, PrSrM/(CSA-PANI) and HCl-PANI film.

  16. Charge transfer in photorechargeable composite films of TiO2 and polyaniline

    NASA Astrophysics Data System (ADS)

    Nomiyama, Teruaki; Sasabe, Kenichi; Sakamoto, Kenta; Horie, Yuji

    2015-07-01

    A photorechargeable battery (PRB) is a photovoltaic device having an energy storage function in a single cell. The photoactive electrode of PRB is a bilayer film consisting of bare porous TiO2 and a TiO2-polyaniline (PANi) mixture that work as a photovoltaic current generator and an electrochemical energy storage by ion dedoping, respectively. To study the charge transfer between TiO2 and PANi, the photorechargeable quantum efficiency QE ([electron count on discharge]/[incident photon count on photocharge]) was measured by varying the thickness LS of the TiO2-PANi mixture. The quantum efficiency QEuv for UV photons had a maximum of ˜7% at LS ˜ 7 µm. The time constant τTP for the charge transfer was about 10-1 s, which was longer ten times or more than the lifetime of excited electrons within TiO2. These facts reveal that the main rate-limiting factor in the photocharging process is the charge transfer between TiO2 and PANi.

  17. Electropolymerization of polypyrrole films doped with sulfonated polyaniline

    NASA Astrophysics Data System (ADS)

    Zhou, Yuanyuan; Yu, Min; Li, Song; Li, Lei

    2008-05-01

    Polypyrrole/ polyaniline (PPy/PAn) composite films have been prepared by direct electrochemical polymerization of pyrrole in an aqueous solution of PAn. Spectroscopic results demonstrated that the polyanion, PAn, was incorporated into the PPy matrix as a dopant. The composite films exhibited a higher thermal stability than that of pure PPy. Scanning electron microscopic images revealed that the composite film had smooth and compact morphology.

  18. Redox-Switchable Surface Wrinkling on Polyaniline Film.

    PubMed

    Xie, Jixun; Zong, Chuanyong; Han, Xue; Ji, Haipeng; Wang, Juanjuan; Yang, Xiu; Lu, Conghua

    2016-04-01

    Here the redox-driven switch between the wrinkled and dewrinkled states on poly-aniline (PANI) film is reported. This switch is derived from the reversible transition in different intrinsic redox states of polyaniline (e.g., between emeraldine salt (ES) and leucoemeraldine base (LEB) or between ES and pernigraniline base (PB)) that are involved in the redox reaction, coupled with the corresponding volume expansion/shrinkage. Interestingly, the as-wrinkled ES film becomes deswollen and dewrinkled when reduced to the LEB state or oxidized to the PB state. Conversely, oxidation of the LEB film or reduction of the PB film into the swollen ES film leads to the reoccurrence of surface wrinkling. Furthermore, the reducibility of the dewrinkled LEB film and the oxidizability of the dewrinkled PB film are well utilized respectively to yield various wrinkled PANI-based composite films.

  19. Layered polyaniline composites with cation-exchanging properties for positive electrodes of rechargeable lithium batteries

    SciTech Connect

    Morita, Masayuki; Miyazaki, Seijiro; Ishikawa, Masashi; Matsuda, Yoshiharu . Dept. of Applied Chemistry and Chemical Engineering); Tajima, Hidehiko . Nagasaki Research and Development Center); Adachi, Kazuyuki; Anan, Fumimiasa . Research Lab.)

    1995-01-01

    Layered polyaniline/polyaniline-polyanion composite films (PAn-X/PAn-PA) were synthesized by electrochemical oxidation of aniline in aqueous acid solutions (HCl, HClO[sub 4]) followed by polymerization in poly(styrene-4-sulfonic acid) (PSSH) solutions. The films consist of inner polyaniline (PAn) layers doped with smaller size anions (X) and outer PSS-doped PAn layers. The resulting films showed high redox activities with cation-transfer properties in organic electrolyte solutions. The improved charge/discharge characteristics of the composite films gave an expectation of higher energy density for the full cell with lithium negative electrode.

  20. Blood coagulation and platelet adhesion on polyaniline films.

    PubMed

    Humpolíček, Petr; Kuceková, Zdenka; Kašpárková, Věra; Pelková, Jana; Modic, Martina; Junkar, Ita; Trchová, Miroslava; Bober, Patrycja; Stejskal, Jaroslav; Lehocký, Marián

    2015-09-01

    Polyaniline is a promising conducting polymer with still increasing application potential in biomedicine. Its surface modification can be an efficient way how to introduce desired functional groups and to control its properties while keeping the bulk characteristics of the material unchanged. The purpose of the study was to synthetize thin films of pristine conducting polyaniline hydrochloride, non-conducting polyaniline base and polyaniline modified with poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) and investigate chosen parameters of their hemocompatibility. The modification was performed either by introduction of PAMPSA during the synthesis or by reprotonation of polyaniline base. The polyaniline hydrochloride and polyaniline base had no impact on blood coagulation and platelet adhesion. By contrast, the polyaniline reprotonated with PAMPSA completely hindered coagulation thanks to its interaction with coagulation factors Xa, Va and IIa. The significantly lower platelets adhesion was also found on this surface. Moreover, this film maintains its conductivity at pH of 6, which is an improvement in comparison with standard polyaniline hydrochloride losing most of its conductivity at pH of 4. Polyaniline film with PAMPSA introduced during synthesis had an impact on platelet adhesion but not on coagulation. The combined conductivity, anticoagulation activity, low platelet adhesion and improved conductivity at pH closer to physiological, open up new possibilities for application of polyaniline reprotonated by PAMPSA in blood-contacting devices, such as catheters or blood vessel grafts.

  1. Blood coagulation and platelet adhesion on polyaniline films.

    PubMed

    Humpolíček, Petr; Kuceková, Zdenka; Kašpárková, Věra; Pelková, Jana; Modic, Martina; Junkar, Ita; Trchová, Miroslava; Bober, Patrycja; Stejskal, Jaroslav; Lehocký, Marián

    2015-09-01

    Polyaniline is a promising conducting polymer with still increasing application potential in biomedicine. Its surface modification can be an efficient way how to introduce desired functional groups and to control its properties while keeping the bulk characteristics of the material unchanged. The purpose of the study was to synthetize thin films of pristine conducting polyaniline hydrochloride, non-conducting polyaniline base and polyaniline modified with poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPSA) and investigate chosen parameters of their hemocompatibility. The modification was performed either by introduction of PAMPSA during the synthesis or by reprotonation of polyaniline base. The polyaniline hydrochloride and polyaniline base had no impact on blood coagulation and platelet adhesion. By contrast, the polyaniline reprotonated with PAMPSA completely hindered coagulation thanks to its interaction with coagulation factors Xa, Va and IIa. The significantly lower platelets adhesion was also found on this surface. Moreover, this film maintains its conductivity at pH of 6, which is an improvement in comparison with standard polyaniline hydrochloride losing most of its conductivity at pH of 4. Polyaniline film with PAMPSA introduced during synthesis had an impact on platelet adhesion but not on coagulation. The combined conductivity, anticoagulation activity, low platelet adhesion and improved conductivity at pH closer to physiological, open up new possibilities for application of polyaniline reprotonated by PAMPSA in blood-contacting devices, such as catheters or blood vessel grafts. PMID:26119372

  2. Engineered Molecular Chain Ordering in Single-Walled Carbon Nanotubes/Polyaniline Composite Films for High-Performance Organic Thermoelectric Materials.

    PubMed

    Wang, Liming; Yao, Qin; Xiao, Juanxiu; Zeng, Kaiyang; Qu, Sanyin; Shi, Wei; Wang, Qun; Chen, Lidong

    2016-06-21

    Single-walled carbon nanotubes (SWNTs)/polyaniline (PANI) composite films with enhanced thermoelectric properties were prepared by combining in situ polymerization and solution processing. Conductive atomic force microscopy and X-ray diffraction measurements confirmed that solution processing and strong π-π interactions between the PANI and SWNTs induced the PANI molecules to form a highly ordered structure. The improved degree of order of the PANI molecular arrangement increased the carrier mobility and thereby enhanced the electrical transport properties of PANI. The maximum in-plane electrical conductivity and power factor of the SWNTs/PANI composite films reached 1.44×10(3)  S cm(-1) and 217 μW m(-1)  K(-2) , respectively, at room temperature. Furthermore, a thermoelectric generator fabricated with the SWNTs/PANI composite films showed good electric generation ability and stability. A high power density of 10.4 μW cm(-2)  K(-1) was obtained, which is superior to most reported results obtained in organic thermoelectric modules. PMID:27123885

  3. Engineered Molecular Chain Ordering in Single-Walled Carbon Nanotubes/Polyaniline Composite Films for High-Performance Organic Thermoelectric Materials.

    PubMed

    Wang, Liming; Yao, Qin; Xiao, Juanxiu; Zeng, Kaiyang; Qu, Sanyin; Shi, Wei; Wang, Qun; Chen, Lidong

    2016-06-21

    Single-walled carbon nanotubes (SWNTs)/polyaniline (PANI) composite films with enhanced thermoelectric properties were prepared by combining in situ polymerization and solution processing. Conductive atomic force microscopy and X-ray diffraction measurements confirmed that solution processing and strong π-π interactions between the PANI and SWNTs induced the PANI molecules to form a highly ordered structure. The improved degree of order of the PANI molecular arrangement increased the carrier mobility and thereby enhanced the electrical transport properties of PANI. The maximum in-plane electrical conductivity and power factor of the SWNTs/PANI composite films reached 1.44×10(3)  S cm(-1) and 217 μW m(-1)  K(-2) , respectively, at room temperature. Furthermore, a thermoelectric generator fabricated with the SWNTs/PANI composite films showed good electric generation ability and stability. A high power density of 10.4 μW cm(-2)  K(-1) was obtained, which is superior to most reported results obtained in organic thermoelectric modules.

  4. Organic Solar Cells Based on Electrodeposited Polyaniline Films

    NASA Astrophysics Data System (ADS)

    Inoue, Kei; Akiyama, Tsuyoshi; Suzuki, Atsushi; Oku, Takeo

    2012-04-01

    Polyaniline thin films as hole transporting layers were fabricated on transparent indium-tin-oxide electrodes by electrodeposition of aniline in an aqueous H2SO4 electrolyte solution. Emerald-green polyaniline films were obtained, which showed stable redox waves. A mixed solution of polythiophene and fullerene derivative was spin-coated onto the electrodeposited polyaniline film. After the modification of titanium oxide film on the surface of the polythiophene/fullerene layer, an aluminum electrode was fabricated by vacuum deposition. The obtained solar cells generated stable photocurrent and photovoltage under light illumination.

  5. Fabrication of superhydrophobic polyaniline films with rapidly switchable wettability

    NASA Astrophysics Data System (ADS)

    Zhou, Xiaoyan; Zhang, Zhaozhu; Men, Xuehu; Yang, Jin; Xu, Xianghui; Zhu, Xiaotao; Xue, Qunji

    2011-10-01

    A superhydrophobic polyaniline (PANI) film has been fabricated by using a facile one-step spraying method. The PANI was synthesized via in situ doping polymerization in the presence of perfluorooctanoic acid (PFOA) as the dopant. The water contact angle of this superhydrophobic surface reaches to 156°. Both the surface chemical compositions and morphological structures were analyzed. A granular morphology of PANI with a moderate amount of nanofibers was obtained. Moreover, a rapid surface wettability transition between superhydrophobicity and superhydrophilicity can be observed when it is doped with PFOA and de-doped with base. The mechanism for this tunable wettability has been discussed in detail.

  6. Polyaniline-polypyrrole composites with enhanced hydrogen storage capacities.

    PubMed

    Attia, Nour F; Geckeler, Kurt E

    2013-06-13

    A facile method for the synthesis of polyaniline-polypyrrole composite materials with network morphology is developed based on polyaniline nanofibers covered by a thin layer of polypyrrole via vapor phase polymerization. The hydrogen storage capacity of the composites is evaluated at room temperature exhibits a twofold increase in hydrogen storage capacity. The HCl-doped polyaniline nanofibers exhibit a storage capacity of 0.46 wt%, whereas the polyaniline-polypyrrole composites could store 0.91 wt% of hydrogen gas. In addition, the effect of the dopant type, counteranion size, and the doping with palladium nanoparticles on the storage properties are also investigated.

  7. Investigation of the properties of polyacrylamide-polyaniline composite and its application as a battery electrode

    SciTech Connect

    Bhat, N.V.; Joshi, N.V. . Dept. of Chemical Technology)

    1993-11-20

    The composite films of polyacrylamide and polyaniline were prepared by polymerizing aniline using ammonium persulfate as an initiator in an aqueous solution containing poly-acrylamide. A film was then cast from this solution. The structural, dynamic mechanical, electrical, and thermal properties of these films have been studied. The infrared spectrum shows the presence of polyacrylamide as well as polyaniline in the composite film. The thermal analysis shows that the composite degrades slower than does the polyacrylamide alone. The dynamic mechanical analysis indicates that there is an increase in the glass transition temperature after the composite formation. The electrical conductivity has been found to increase by more than eight orders of magnitude. These composite films have also been suitably used as electrodes in secondary batteries.

  8. Electrical characterization of gold and platinum thin film electrodes with polyaniline modified surfaces

    NASA Astrophysics Data System (ADS)

    Aggas, John Richard

    Recent studies into soft organic electronics have burgeoned as a result of discoveries of conducting polymers such as polyaniline, polythiophene, and polypyrrole. However, in order to make these conducting polymers suitable for in vivo soft organic electronics, they must be developed so that they can be biocompatible and provide accurate sensing. Chitosan, a naturally occurring polymer structure found in exoskeletons of crustaceans, has been studied for its biocompatible properties. Composites of polyaniline (PAn), an intrinsically conductive polymer (ICP) and chitosan (Chi), a biopolymer, were developed and applied to gold and platinum Thin Film Electrode (TFE) devices. Electropolymerization and drop cast deposition were utilized to modify TFEs with a thin film of PAn or PAn-Chi composite. The impedance response over a spectrum of frequencies was studied for blank control TFEs, platinized TFEs, and platinized TFEs with various polyaniline coatings. Impedance measurements were taken in dry environments, DI Water, and in buffers such as PBS, and HEPES. Current-Voltage (I-V) characterization was used to study the current response and SEM imaging was used to study the surface topography. Resistance was measured for PAn modified unplatinized gold TFEs with varying amounts of incorporated chitosan. Impedance measurements of control and platinized TFEs yielded results similar to a low pass filter. Due to the conductive nature of polyaniline, the impedance of TFEs decreased substantially after poylaniline deposition. Measured resistance values for polyaniline and chitosan composites on TFEs revealed a window of concentrations of incorporated chitosan to lower resistance.

  9. Ammonia gas sensing behavior of tanninsulfonic acid doped polyaniline-TiO₂ composite.

    PubMed

    Bairi, Venu Gopal; Bourdo, Shawn E; Sacre, Nicolas; Nair, Dev; Berry, Brian C; Biris, Alexandru S; Viswanathan, Tito

    2015-10-16

    A highly active tannin doped polyaniline-TiO₂ composite ammonia gas sensor was developed and the mechanism behind the gas sensing activity was reported for the first time. A tanninsulfonic acid doped polyaniline (TANIPANI)-titanium dioxide nanocomposite was synthesized by an in situ polymerization of aniline in the presence of tanninsulfonic acid and titanium dioxide nanoparticles. X-ray diffraction and thermogravimetric analysis were utilized to determine the incorporation of TiO₂ in TANIPANI matrix. UV-Visible and infrared spectroscopy studies provided information about the electronic interactions among tannin, polyaniline, and TiO₂. Scanning electron microscopy (SEM) along with energy dispersive X-ray spectroscopy (EDS) and atomic force microscopy (AFM) surface analysis techniques were used to investigate the metal oxide dispersions inside polyaniline matrix. Gas sensors were prepared by spin coating solutions of TANIPANI-TiO₂ and TANIPANI composites onto glass slides. Sensors were tested at three different concentrations (20 ppm, 40 ppm, and 60 ppm) of ammonia gas at ambient temperature conditions by measuring the changes in surface resistivity of the films with respect to time. Ammonia gas sensing plots are presented showing the response values, response times and recovery times. The TANIPANI-TiO₂ composite exhibited better response and shorter recovery times when compared to TANIPANI control and other polyaniline composites that have been reported in the literature. For the first time a proposed mechanism of gas sensing basing on the polaron band localization and its effects on the gas sensing behavior of polyaniline are reported.

  10. Room temperature ammonia sensor based on copper nanoparticle intercalated polyaniline nanocomposite thin films

    NASA Astrophysics Data System (ADS)

    Patil, U. V.; Ramgir, Niranjan S.; Karmakar, N.; Bhogale, A.; Debnath, A. K.; Aswal, D. K.; Gupta, S. K.; Kothari, D. C.

    2015-06-01

    Thin films of copper nanoparticles intercalated-polyaniline nanocomposites (NC) have been deposited at room temperatures by in situ oxidative polymerization of aniline in the presence of different concentrations of Cu nanoparticles. The response characteristics of the NC thin films toward different gases namely NH3, CO, CO2, NO and CH4 were examined at room temperature. Both pure polyaniline (PANI) and NC films exhibited a selective response toward NH3. Incorporation of Cu nanoparticles resulted in an improvement of the sensors response and response kinetics. The response and the recovery times of composite film toward 50 ppm of NH3 were 7 and 160 s, respectively. Additionally, the NC sensor film could reversibly detect as low as 1 ppm of NH3 concentrations. The enhanced response of NC films toward NH3 is attributed to the deprotonation and reprotonation processes as also supported by Raman investigations.

  11. Magnetoactive feature of in-situ polymerised polyaniline film developed on the surface of manganese-zinc ferrite

    NASA Astrophysics Data System (ADS)

    Babayan, V.; Kazantseva, N. E.; Sapurina, I.; Moučka, R.; Vilčáková, J.; Stejskal, J.

    2012-07-01

    A polyaniline film exhibits magnetoactive properties when deposited on the surface of multidomain particles of manganese-zinc ferrite during in-situ polymerisation of aniline. This is reflected in the increased coercivity and thermomagnetic stability of an in-situ prepared composite compared with bare ferrite and its mixed composite with polyaniline. In addition, the deposition of a polyaniline film results in a shift of the complex-permeability dispersion region towards ultrahigh frequency band. These changes in the magnetic properties of polyaniline-coated ferrite are attributed to the increased value of the inner demagnetisation factor, which results from stress-induced magnetic anisotropy due to the pinning of domain walls appearing on the surface of ferrite. This study is focused on the mechanism of pinning of domain walls and its influence on the magnetic properties of in-situ prepared composites in terms of the molecular mechanism of oxidative polymerisation of aniline. Ferrite stimulates the propagation of polyaniline chains, which start to grow on the domain walls on the ferrite surface. It leads to the pinning of domain walls and restricts their mobility in a magnetic field. The further increase in the coercivity and the resonance frequency of polyaniline-coated ferrite due to film shrinkage after deprotonation of polyaniline makes it obvious that polyaniline coating induces elastic stresses in a ferrite particle that stimulate the growth of the effective magnetic anisotropy. Stress-induced magnetic anisotropy contributes to the reorientation of the magnetisation vectors in domains with respect to the new directions of easy magnetisation, given by magnetoelastic stresses, which leads to complex changes in the magnetic properties of in-situ prepared composites.

  12. Electrical and thermal properties of graphite/polyaniline composites

    SciTech Connect

    Bourdo, Shawn E.; Warford, Brock A.; Viswanathan, Tito

    2012-12-15

    A composite of a carbon allotrope (graphite) and an inherently conducting polymer, polyaniline (PANI), has been prepared that exhibits an electrical conductivity greater than either of the two components. An almost 2-fold increase in the bulk conductivity occurs when only a small mass fraction of polyaniline exists in the composite (91% graphite/ 9% polyaniline, by mass). This increase in dc electrical conductivity is curious since in most cases a composite material will exhibit a conductivity somewhere between the two individual components, unless a modification to the electronic nature of the material occurs. In order to elucidate the fundamental electrical properties of the composite we have performed variable temperature conductivity measurements to better understand the nature of conduction in these materials. The results from these studies suggest a change in the mechanism of conduction as the amount of polyaniline is increased in the composite. Along with superior electrical properties, the composites exhibit an increase in thermal stability as compared to the graphite. - Graphical abstract: (Left) Room temperature electrical conductivity of G-PANI composites at different mass ratios. (Right) Electrical conductivity of G-PANI composites at temperatures from 5 K to 300 K. Highlights: Black-Right-Pointing-Pointer Composites of graphite and polyaniline have been synthesized with unique electrical and thermal properties. Black-Right-Pointing-Pointer Certain G-PANI composites are more conductive and more thermally stable than graphite alone. Black-Right-Pointing-Pointer G-PANI composites exhibit a larger conductivity ratio with respect to temperature than graphite alone.

  13. Nanostructured metal-polyaniline composites and applications thereof

    DOEpatents

    Wang, Hsing-Lin; Li, Wenguang; Bailey, James A.; Gao, Yuan

    2012-10-02

    Metal-polyaniline (PANI) composites are provided together with a process of preparing such composites by an electrodeless process. The metal of the composite can have nanoscale structural features and the composites can be used in applications such as catalysis for hydrogenation reactions and for analytical detection methods employing SERS.

  14. Anodic deprotonation of polyaniline films in alcohol solutions

    SciTech Connect

    Susumu Kuwabata, Nobuo Kihira ); Hiroshi Yoneyama

    1993-05-01

    Polyaniline films prepared by electrochemical oxidation of aniline possess high redox activities both in aqueous acidic and in nonaqueous solutions. The high durability of the film against the redox cycling opens applications of this material to electrochromic and electronic devices and cathode-active materials of rechargeable lithium batteries. Polyaniline films immersed in alcohol solutions such as methanol, ethanol, 1-propanol, and 2-propanol are deprotonated by applying anodic potentials. The potential at which the deprotonation reaction is induced to occur is the most negative at methanol among the above four kinds of alcohols used, and ethanol, 1-propanol, and 2-propanol follow in this order. This finding is quantitatively discussed in terms of the difference of the affinity of the solvent for the protonated polyaniline. An equation to predict the potential at which the conductance of polyaniline is decreased to one-half of the highest conductance by the deprotonation is derived, and the validity of the equation is verified for results obtained both in aqueous solutions of different pH values and in the above alcohol solutions. 26 refs., 9 figs.

  15. Comparison of chemically and electrochemically synthesized polyaniline films

    SciTech Connect

    Hatchett, D.W.; Josowicz, M.; Janata, J.

    1999-12-01

    The electrochemical growth of thick ({approximately}2 mm) emeraldine, polyaniline (PANI{sup E}) films from solutions containing 2 M HBF{sub 4} and 0.25 M aniline is demonstrated. Electrochemically and chemically prepared PANI{sup E} films, cast from formic acid solutions, are compared. The combination of electrochemical results with Fourier transform infrared spectroscopic data indicates that pure and homogeneous standard material can be reproducibly prepared electrochemically.

  16. Temperature dependent electrical properties of polyaniline film grown on paper through aniline vapor polymerization

    NASA Astrophysics Data System (ADS)

    Deb, K.; Bhowmik, K. L.; Bera, A.; Chattopadhyay, K. K.; Saha, B.

    2016-05-01

    Polyaniline thin film has been prepared on paper by aniline vapor deposition technique. Ferric chloride has been used as polymerizing agent in this approach. The prepared films were studied through electrical resistivity and optical properties measurements. The electrical resistivity of the polyaniline film shows significant temperature dependence. The resistance sharply falls with the increase in temperature. The optical absorbance measurements shows characteristics absorbance peak indicating the formation of conducting emeraldine salt form of polyaniline. The optical energy band gap of the film was calculated from the transmittance spectra. The optical energy band gap and electrical conductivity of the polyaniline film is well suited for their applications in electronic devices.

  17. Ammonia Gas Sensing Behavior of Tanninsulfonic Acid Doped Polyaniline-TiO2 Composite

    PubMed Central

    Bairi, Venu Gopal; Bourdo, Shawn E.; Sacre, Nicolas; Nair, Dev; Berry, Brian C.; Biris, Alexandru S.; Viswanathan, Tito

    2015-01-01

    A highly active tannin doped polyaniline-TiO2 composite ammonia gas sensor was developed and the mechanism behind the gas sensing activity was reported for the first time. A tanninsulfonic acid doped polyaniline (TANIPANI)-titanium dioxide nanocomposite was synthesized by an in situ polymerization of aniline in the presence of tanninsulfonic acid and titanium dioxide nanoparticles. X-ray diffraction and thermogravimetric analysis were utilized to determine the incorporation of TiO2 in TANIPANI matrix. UV-Visible and infrared spectroscopy studies provided information about the electronic interactions among tannin, polyaniline, and TiO2. Scanning electron microscopy (SEM) along with energy dispersive X-ray spectroscopy (EDS) and atomic force microscopy (AFM) surface analysis techniques were used to investigate the metal oxide dispersions inside polyaniline matrix. Gas sensors were prepared by spin coating solutions of TANIPANI-TiO2 and TANIPANI composites onto glass slides. Sensors were tested at three different concentrations (20 ppm, 40 ppm, and 60 ppm) of ammonia gas at ambient temperature conditions by measuring the changes in surface resistivity of the films with respect to time. Ammonia gas sensing plots are presented showing the response values, response times and recovery times. The TANIPANI-TiO2 composite exhibited better response and shorter recovery times when compared to TANIPANI control and other polyaniline composites that have been reported in the literature. For the first time a proposed mechanism of gas sensing basing on the polaron band localization and its effects on the gas sensing behavior of polyaniline are reported. PMID:26501291

  18. Synthesis, Characterization, and Electrochemical Properties of Polyaniline Thin Films

    NASA Astrophysics Data System (ADS)

    Rami, Soukaina

    Conjugated polymers have been used in various applications (battery, supercapacitor, electromagnetic shielding, chemical sensor, biosensor, nanocomposite, light-emitting-diode, electrochromic display etc.) due to their excellent conductivity, electrochemical and optical properties, and low cost. Polyaniline has attracted the researchers from all disciplines of science, engineering, and industry due to its redox properties, environmental stability, conductivity, and optical properties. Moreover, it is a polymer with fast electroactive switching and reversible properties displayed at low potential, which is an important feature in many applications. The thin oriented polyaniline films have been fabricated using self-assembly, Langmuir-Blodgett, in-situ self-assembly, layer-by-layer, and electrochemical technique. The focus of this thesis is to synthesize and characterize polyaniline thin films with and without dyes. Also, the purpose of this thesis is to find the fastest electroactive switching PANI electrode in different electrolytic medium by studying their electrochemical properties. These films were fabricated using two deposition techniques: in-situ self-assembly and electrochemical deposition. The characterization of these films was done using techniques such as Fourier Transform Infrared Spectroscopy (FTIR), UV-spectroscopy, Scanning Electron Microscope (SEM), and X-Ray Diffraction (XRD). FTIR and UV-spectroscopy showed similar results in the structure of the polyaniline films. However, for the dye incorporated films, since there was an addition in the synthesis of the material, peak locations shifted, and new peaks corresponding to these materials appeared. The 1 layer PANI showed compact film morphology, comparing to other PANI films, which displayed a fiber-like structure. Finally, the electrochemical properties of these thin films were studied using cyclic voltammetry (CV), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS) in

  19. Electrodeposited conductive polypyrrole/polyaniline composite film for the corrosion protection of copper bipolar plates in proton exchange membrane fuel cells

    NASA Astrophysics Data System (ADS)

    Pan, T. J.; Zuo, X. W.; Wang, T.; Hu, J.; Chen, Z. D.; Ren, Y. J.

    2016-01-01

    A conductive composite coating consisting of an inner polypyrrole (PPY) layer and an outer polyaniline (PANI) layer is prepared on a copper substrate by an electrochemical synthesis. Potential application of these composite coatings in a proton exchange membrane fuel cell (PEMFC) is evaluated. The corrosion performance of the copper substrate without and with the polymer coatings in the acidic solutions containing H2SO4 (0.2 M), HCl (0.1 M) and HF (3 ppm) is investigated by electrochemical impedance spectroscopy, polarization and open-circuit potential measurements. The results indicate that both the bilayered PPY/PANI and the single PPY coating can increase the corrosion potential of copper substrate by more than 250 mV (SCE), and effectively decrease the corrosion current density by an order of magnitude in comparison with the uncoated copper substrate. Long-term test further confirms that the bilayered PPY/PANI coating with acceptable contact resistance provides better protection for the substrate than the single PPY coating. The bilayered structure with different ion-permselective nature may serve as an effective physical barrier to the inward penetration of corrosive species.

  20. Perspectives on State-of-the-Art Carbon Nanotube/Polyaniline and Graphene/Polyaniline Composites for Hybrid Supercapacitor Electrodes.

    PubMed

    Srikanth, Vadali V S S; Ramana, Gedela Venkata; Kumar, Puttapati Sampath

    2016-03-01

    Supercapacitors are attractive alternative energy storage sources. They offer high energy/power density with other characteristics like fast discharge/charge time, long operation stability, safety etc. In a supercapacitor, working electrode material is the principal constituent. At present there are numerous electrode materials (with properties) suitable for their use in hybrid type supercapacitors. Carbon/polyaniline (PANi) composites are one class of such electrode materials. Here, perspectives on state-of-the-art carbon/PANi composites namely carbon nanotube/polyaniline and graphene/polyaniline composites expedient as hybrid type supercapacitor electrode materials will be presented. PMID:27455650

  1. Perspectives on State-of-the-Art Carbon Nanotube/Polyaniline and Graphene/Polyaniline Composites for Hybrid Supercapacitor Electrodes.

    PubMed

    Srikanth, Vadali V S S; Ramana, Gedela Venkata; Kumar, Puttapati Sampath

    2016-03-01

    Supercapacitors are attractive alternative energy storage sources. They offer high energy/power density with other characteristics like fast discharge/charge time, long operation stability, safety etc. In a supercapacitor, working electrode material is the principal constituent. At present there are numerous electrode materials (with properties) suitable for their use in hybrid type supercapacitors. Carbon/polyaniline (PANi) composites are one class of such electrode materials. Here, perspectives on state-of-the-art carbon/PANi composites namely carbon nanotube/polyaniline and graphene/polyaniline composites expedient as hybrid type supercapacitor electrode materials will be presented.

  2. Synthesis and structural characterization of polyaniline/cobalt chloride composites

    NASA Astrophysics Data System (ADS)

    Asha, Goyal, Sneh Lata; Kishore, Nawal

    2016-05-01

    Polyaniline (PANI) and PANI /cobalt chloride composites were synthesized by in situ chemical oxidative polymerization of aniline with CoCl2.6H2O using ammonium peroxidisulphate as an oxidant. These composites were characterized by X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The XRD study reveals that both PANI and composites are amorphous. The XRD and SEM results confirm the presence of cobalt chloride in the composites.

  3. Virus Sorbents Based on Polyaniline Interpolymer Complexes, Composites and their Sorption Properties

    NASA Astrophysics Data System (ADS)

    Ivanov, Victor F.; Ivanova, Valeria T.; Kurochkina, Yanina E.; Gribkova, Oksana L.; Ilyina, Maria V.; Manykin, Anatoly A.; Isakova, Aleksandra A.; Sapurina, Irina Yu.

    2010-06-01

    Complexes between influenza viruses proteins and antibodies to them create the precipitation lines in polyaniline (PAn) films which were detected by polarization optical microscopy after coating the film from the top the eutectic mixture of nematic liquid crystals MBBA:EBBA. Polyaniline and it's composites interact as sorbents with influenza human and bird viruses apart from antigenic properties of surface proteins as well as with bacteriophage T4-D. The sorption of virions occurred in different solutions in the temperature range (8-25 ° C) during 15-60 min. After contact with sorbent the HA titers of influenza virus in solutions were decreased in 4 -2048 times. The immobilized influenza viruses were able to interact with homological antibodies from immune sera in solution.

  4. Surface modification of polyacrylonitrile film by anchoring conductive polyaniline and determination of uricase adsorption capacity and activity

    NASA Astrophysics Data System (ADS)

    Bayramoğlu, Gülay; Metin, Ayşegul Ü.; Arıca, M. Yakup

    2010-09-01

    Polyacrylonitrile (PAN) films were modified with chemical polymerization of conductive polyaniline (PANI) in the presence of potassium dichromate as an oxidizing agent. The effect of aniline concentration on the grafting efficiency and on the electrical surface resistance of PAN and (PAN/PANI)-1-3 composite film was investigated. The surface resistances of the conductive composite films were found to be between 6.32 and 0.97 kΩ/cm. As the amount of grafted PANI increased on the PAN films, the electrical resistance of composite film decreased. The PAN/PANI composite films were also characterized using SEM and FTIR. The changes in the surface properties of the films were characterized by contact angle measurements. As expected, the PAN, PAN/PANI and PAN/PANI-uricase immobilized films, exhibited different contact angle values and surface free energy due to different interactive functional groups of the films. The conductive films were well characterized and used for immobilization of uricase. The amount of adsorbed enzyme increases with the increase of surface concentration of grafted fibrous polyaniline polymer. The maximum amount of immobilized enzyme onto composite film containing 2.4% PANI was about 216 μg/cm 2 (i.e., PAN/PANI-3). The immobilized uricase was reused 24 times in batch wise assay in a day. Finally, the immobilized uricase enzyme system was successfully fabricated and applied to determine the uric acid level in human serum samples.

  5. Fabrication and Electrochemical Characterization of Polyaniline/Titanium Oxide Nanoweb Composite Electrode for Supercapacitor Application.

    PubMed

    Yu, Hyunuk; Jang, Kihun; Chung, Ildoo; Ahn, Heejoon

    2016-03-01

    In this study, polyaniline/titanium oxide (PANi-TiO2) nanoweb composite was fabricated through electrochemical deposition and electrospinning techniques, and the composite was further utilized as an electrode for a supercapacitor. The PANi-TiO2 composite film showed three-dimensional hierarchical micro/nano architecture. The film was deposited on the current collector without the use of any binders. The morphology of the PANi-TiO2 composite film was confirmed by the use of field emission scanning electron microscopy (FE-SEM) analysis that polyaniline was grown in the form of nanorods with a diameter of 100 nm-200 nm on a TiO2 nanoweb. The chemical composition and quantitative analysis were determined by X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), and thermogravimetric analysis (TGA). The electrochemical properties were analyzed by cyclic voltammetry (CV), chronopotentiometry, and electrochemical impedance spectroscopy (EIS). The result of electrochemical tests indicated that TiO2-PANi electrode displayed a high specific capacitance of 306.5 Fg(-1) at the scan rate of 20 mVs(-1), with the capacitance retention ratio being 103% after 500 cycles at the scan rate of 50 mVs(-1).

  6. Ultrasensitive Gold Nanostar-Polyaniline Composite for Ammonia Gas Sensing.

    PubMed

    Kumar, Vished; Patil, Vithoba; Apte, Amey; Harale, Namdev; Patil, Pramod; Kulkarni, Sulabha

    2015-12-01

    Gold in the form of bulk metal mostly does not react with gases or liquids at room temperature. On the other hand, nanoparticles of gold are very reactive and useful as catalysts. The reactivity of nanoparticles depends on the size and the morphology of the nanoparticles. Gold nanostars containing copper have rough surfaces and large numbers of active sites due to tips, sides, corners, and large surface area-to-volume ratios due to their branched morphology. Here the sensitivity of the gold nanostar-polyaniline composite (average size of nanostars ∼170 nm) toward ammonia gas has been investigated. For 100 ppm ammonia, the sensitivity of the composite increased to 52% from a mere 7% value for pure polyaniline. The gold nanostar-polyaniline composite even showed a response time as short as 15 s at room temperature. The gold nanostars act as a catalyst in the nanocomposite. The stability and sensitivity at different concentrations and the selectivity for ammonia gas were also investigated.

  7. Ultrasensitive Gold Nanostar-Polyaniline Composite for Ammonia Gas Sensing.

    PubMed

    Kumar, Vished; Patil, Vithoba; Apte, Amey; Harale, Namdev; Patil, Pramod; Kulkarni, Sulabha

    2015-12-01

    Gold in the form of bulk metal mostly does not react with gases or liquids at room temperature. On the other hand, nanoparticles of gold are very reactive and useful as catalysts. The reactivity of nanoparticles depends on the size and the morphology of the nanoparticles. Gold nanostars containing copper have rough surfaces and large numbers of active sites due to tips, sides, corners, and large surface area-to-volume ratios due to their branched morphology. Here the sensitivity of the gold nanostar-polyaniline composite (average size of nanostars ∼170 nm) toward ammonia gas has been investigated. For 100 ppm ammonia, the sensitivity of the composite increased to 52% from a mere 7% value for pure polyaniline. The gold nanostar-polyaniline composite even showed a response time as short as 15 s at room temperature. The gold nanostars act as a catalyst in the nanocomposite. The stability and sensitivity at different concentrations and the selectivity for ammonia gas were also investigated. PMID:26522375

  8. Effect of HCl doping on optoelectrical and LPG sensing properties of nanostructured polyaniline thin films

    NASA Astrophysics Data System (ADS)

    Upadhye, Deepak S.; Huse, Nanasaheb P.; Sharma, Ramphal

    2016-05-01

    Nanostructure Polyaniline thin films doped with 0.5 M, 0.7 M, and 1 M of HCL were synthesized by simple and inexpensive chemical oxidative polymerization technique at room temperature. All prepared thin films of Polyaniline were characterized by optical absorbance study by UV-visible spectroscopy. The absorbance spectrum of Polyaniline shows three fundamental peaks at 356, 419 and 820 nm with increase in absorption intensity. The electrical study shows magnitude of resistance of HCL doped Polyaniline is dependent on doping level. Furthermore, the thin film of Polyaniline was investigated by Scanning electron microscopy for surface morphology study. The SEM micrograph represents irregular granular morphology. In order to investigate LPG sensing properties, I-V characteristics of the Polyaniline films doped with 0.5 M, 0.7 M, and 1 M of HCL were recorded at room temperature in presence of air and 100 ppm of LPG. The observed values of sensitivity found to be 7.21%, 9.85% and 17.46 % for 0.5 M, 0.75 M, and 1.0 M of HCL doped Polyaniline thin films respectively

  9. Composition dependent magnetic properties of iron oxide-polyaniline nanoclusters

    SciTech Connect

    Sharma, Raksha; Lamba, Subhalakshmi; Annapoorni, S.; Sharma, Parmanand; Inoue, Akihisa

    2005-01-01

    {gamma}-Fe{sub 2}O{sub 3} prepared by sol gel process was used to produce nanocomposites with polyaniline of varying aniline concentrations. Transmission electron microscopy (TEM) shows the presence of chain like structure for lower polyaniline concentration. The room temperature hysteresis curves show finite coercivity of {approx}160 Oe for all the composites, while the saturation magnetization was found to decrease with increasing polymer content. Zero field cooled-field cooled magnetization measurements indicate high blocking temperatures. It is believed that this indicates a strongly interacting system, which is also shown by our TEM results. Monte Carlo simulations performed on a random anisotropy model with dipolar and exchange interactions match well with experimental results.

  10. Particle size distributions of polyaniline-silica colloidal composites

    SciTech Connect

    Gill, M.; Armes, S.P. ); Fairhurst, D. ); Emmett, S.N. ); Idzorek, G.; Pigott, T. )

    1992-09-01

    We have characterized a new polyaniline-silica composite colloid by various particle sizing techniques. Our transmission electron microscopy studies have confirmed for the first time an unusual raspberry morphology, with the small silica particles held together by the polyaniline [open quotes]binder[close quotes]. These particles have average diameters in the size range 150-500 nm. Charge-velocity analysis experiments indicated a number-average particle diameter of 300 [plus minus] 80 nm, but only poor statistics were obtained (172 particles counted). Photon correlation spectroscopy studies suggested an intensity-average particle diameter of 380 nm. Disk centrifuge photosedimentometry (DCP) turned out to be our preferred sizing technique for the polyaniline-silica colloids, since it was both quick and reliable and, more importantly, produced the true particle size distribution (PSD) curve with excellent statistics. The DCP data indicated a weight-average and number-average particle diameter of 330 [plus minus] 70 nm and 280 [plus minus] 70 nm, respectively, and moreover confirmed the PSD to be both broad and unimodal. Finally, these colloidal composites were sized using the Malvern Aerosizer. Using this instrument in conjunction with a nebulizer attachment (which allowed particle sizing of the [open quotes]wet[close quotes] dispersion) rather than in the conventional [open quotes]dry powder[close quotes] mode, we obtained particle size data which were in reasonable agreement with the DCP results. 31 refs., 5 figs., 1 tab.

  11. Cysteine modified polyaniline films improve biocompatibility for two cell lines.

    PubMed

    Yslas, Edith I; Cavallo, Pablo; Acevedo, Diego F; Barbero, César A; Rivarola, Viviana A

    2015-06-01

    This work focuses on one of the most exciting application areas of conjugated conducting polymers, which is cell culture and tissue engineering. To improve the biocompatibility of conducting polymers we present an easy method that involves the modification of the polymer backbone using l-cysteine. In this publication, we show the synthesis of polyaniline (PANI) films supported onto Polyethylene terephthalate (PET) films, and modified using cysteine (PANI-Cys) in order to generate a biocompatible substrate for cell culture. The PANI-Cys films are characterized by Fourier Transform infrared and UV-visible spectroscopy. The changes in the hydrophilicity of the polymer films after and before the modification were tested using contact angle measurements. After modification the contact angle changes from 86°±1 to 90°±1, suggesting a more hydrophylic surface. The adhesion properties of LM2 and HaCaT cell lines on the surface of PANI-Cys films in comparison with tissue culture plastic (TCP) are studied. The PANI-Cys film shows better biocompatibility than PANI film for both cell lines. The cell morphologies on the TCP and PANI-Cys film were examined by florescence and Atomic Force Microscopy (AFM). Microscopic observations show normal cellular behavior when PANI-Cys is used as a substrate of both cell lines (HaCaT and LM2) as when they are cultured on TCP. The ability of these PANI-Cys films to support cell attachment and growth indicates their potential use as biocompatible surfaces and in tissue engineering.

  12. Biocompatible novel starch/polyaniline composites: characterization, anti-cytotoxicity and antioxidant activity.

    PubMed

    Saikia, Jyoti Prasad; Banerjee, Somik; Konwar, Bolin Kumar; Kumar, Ashok

    2010-11-01

    Starch/polyaniline composites have been synthesized using oxidative polymerization of polyaniline in an aqueous dispersion of starch isolated from Colocasia esculenta corm. Scanning electron micrographs reveals the growth of polyaniline over the surface of the starch granules. DPPH scavenging and haemolysis prevention assay have been performed to estimate the antioxidant activity and cytotoxicity of the composites. Formation of new properties of the composites as compared to starch and poloyaniline was evident from the X-ray diffraction analysis (XRD). Characterization done using UV-Vis, FTIR and DSC analysis provide evidence of composite formation. Composite possesses antioxidant nature which increases with the concentration of polyaniline. The haemolysis prevention activity of these novel composite materials is found to increase as compared to the pure polyaniline with minor compromise in the antioxidant activity. The materials show tremendous potential for biomedical applications. PMID:20674287

  13. Microwave absorbing properties of polyaniline/multi-walled carbon nanotube composites with various polyaniline contents

    NASA Astrophysics Data System (ADS)

    Ting, T. H.; Jau, Y. N.; Yu, R. P.

    2012-01-01

    Polyaniline/multi-walled carbon nanotube (PANI/MWNT) composites were synthesized using in situ polymerization at different aniline/multi-walled carbon nanotube weight ratios (Ani/MWNT = 1/2, 1/1, 2/1 and 3/1) and introduced into an epoxy resin to act as a microwave absorber. The spectroscopic characterization of the process of formation of PANI/MWNT composites were studied using Fourier transform infrared spectroscopy, an ultraviolet-visible spectrophotometer, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and electron spin resonance. The microwave absorbing properties were investigated by measuring complex permittivity, complex permeability and reflection loss in the 2-18 and 18-40 GHz microwave frequency range, using the free space method. The results showed that the addition of PANI was useful for achieving a large absorption over a wide frequency range, especially for higher frequency values.

  14. Synthesis and characterization of conducting polyaniline-copper composites.

    PubMed

    Liu, Aijie; Bac, Luong Huu; Kim, Ji-Soon; Kim, Byoung-Kee; Kim, Jin-Chun

    2013-11-01

    Conducting polymer composites have many interesting physical properties and important application potentials. Suitable combinations of metal nanoparticles with conductive polymers can result in composite materials having unique physical and chemical properties that can have wide application potential in diverse areas. In this work, copper nanoparticles were fabricated by electrical explosion of wire (EEW) in solution of polyacrylic acid (PAA) and ethanol. Conductive polyaniline-copper (PANI-Cu) composites have been synthesized by in-situ polymerization of aniline in the fabricated copper suspension. Optical absorption in the UV-visible region of these suspensions was measured in the range of 200-900 nm. Morphology and structure of the composites were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and Fourier-transform infrared spectra (FTIR). Pure copper nanoparticles were uniformly dispersed into the polymer matrix. Thermal stability of the composites was characterized by thermogravimetric analysis (TGA). Electrical conductivity measurements indicated that the conductivity of the composites was higher than that of pure polyaniline and increased with increasing content of copper.

  15. Bacteria counting method based on polyaniline/bacteria thin film.

    PubMed

    Zhihua, Li; Xuetao, Hu; Jiyong, Shi; Xiaobo, Zou; Xiaowei, Huang; Xucheng, Zhou; Tahir, Haroon Elrasheid; Holmes, Mel; Povey, Malcolm

    2016-07-15

    A simple and rapid bacteria counting method based on polyaniline (PANI)/bacteria thin film was proposed. Since the negative effects of immobilized bacteria on the deposition of PANI on glass carbon electrode (GCE), PANI/bacteria thin films containing decreased amount of PANI would be obtained when increasing the bacteria concentration. The prepared PANI/bacteria film was characterized with cyclic voltammetry (CV) technique to provide quantitative index for the determination of the bacteria count, and electrochemical impedance spectroscopy (EIS) was also performed to further investigate the difference in the PANI/bacteria films. Good linear relationship of the peak currents of the CVs and the log total count of bacteria (Bacillus subtilis) could be established using the equation Y=-30.413X+272.560 (R(2)=0.982) over the range of 5.3×10(4) to 5.3×10(8)CFUmL(-1), which also showed acceptable stability, reproducibility and switchable ability. The proposed method was feasible for simple and rapid counting of bacteria. PMID:26921555

  16. The effect of carbon nanofillers on the performance of electromechanical polyaniline-based composite actuators

    NASA Astrophysics Data System (ADS)

    García-Gallegos, J. C.; Martín-Gullón, I.; Conesa, J. A.; Vega-Cantú, Y. I.; Rodríguez-Macías, F. J.

    2016-01-01

    Different types of crystalline carbon nanomaterials were used to reinforce polyaniline for use in electromechanical bilayer bending actuators. The objective is to analyze how the different graphitic structures of the nanocarbons affect and improve the in situ polymerized polyaniline composites and their subsequent actuator behavior. The nanocarbons investigated were multiwalled carbon nanotubes, nitrogen-doped carbon nanotubes, helical-ribbon carbon nanofibers and graphene oxide, each one presenting different shape and structural characteristics. Films of nanocarbon-PAni composite were tested in a liquid electrolyte cell system. Experimental design was used to select the type of nanocarbon filler and composite loadings, and yielded a good balance of electromechanical properties. Raman spectroscopy suggests good interaction between PAni and the nanocarbon fillers. Electron microscopy showed that graphene oxide dispersed the best, followed by multiwall carbon nanotubes, while nitrogen-doped nanotube composites showed dispersion problems and thus poor performance. Multiwall carbon nanotube composite actuators showed the best performance based on the combination of bending angle, bending velocity and maximum working cycles, while graphene oxide attained similarly good performance due to its best dispersion. This parallel testing of a broad set of nanocarbon fillers on PAni-composite actuators is unprecedented to the best of our knowledge and shows that the type and properties of the carbon nanomaterial are critical to the performance of electromechanical devices with other conditions remaining equal.

  17. The effect of carbon nanofillers on the performance of electromechanical polyaniline-based composite actuators.

    PubMed

    García-Gallegos, J C; Martín-Gullón, I; Conesa, J A; Vega-Cantú, Y I; Rodríguez-Macías, F J

    2016-01-01

    Different types of crystalline carbon nanomaterials were used to reinforce polyaniline for use in electromechanical bilayer bending actuators. The objective is to analyze how the different graphitic structures of the nanocarbons affect and improve the in situ polymerized polyaniline composites and their subsequent actuator behavior. The nanocarbons investigated were multiwalled carbon nanotubes, nitrogen-doped carbon nanotubes, helical-ribbon carbon nanofibers and graphene oxide, each one presenting different shape and structural characteristics. Films of nanocarbon-PAni composite were tested in a liquid electrolyte cell system. Experimental design was used to select the type of nanocarbon filler and composite loadings, and yielded a good balance of electromechanical properties. Raman spectroscopy suggests good interaction between PAni and the nanocarbon fillers. Electron microscopy showed that graphene oxide dispersed the best, followed by multiwall carbon nanotubes, while nitrogen-doped nanotube composites showed dispersion problems and thus poor performance. Multiwall carbon nanotube composite actuators showed the best performance based on the combination of bending angle, bending velocity and maximum working cycles, while graphene oxide attained similarly good performance due to its best dispersion. This parallel testing of a broad set of nanocarbon fillers on PAni-composite actuators is unprecedented to the best of our knowledge and shows that the type and properties of the carbon nanomaterial are critical to the performance of electromechanical devices with other conditions remaining equal. PMID:26595669

  18. Polyaniline/single-walled carbon nanotube composite electronic devices

    NASA Astrophysics Data System (ADS)

    Ramamurthy, P. C.; Malshe, A. M.; Harrell, W. R.; Gregory, R. V.; McGuire, K.; Rao, A. M.

    2004-11-01

    Composites of high molecular weight polyaniline (PANI) and various weight percentages of single-walled carbon nanotubes (SWNT) were fabricated using solution processing. Electrical characteristics of metal-semiconductor (MS) devices fabricated from the PANI/SWNT composites were studied. Current-voltage ( I- V) characteristics of these devices indicate a significant increase in current with an increase in carbon nanotube concentration in the composite. The dominant transport mechanisms operating in these devices were investigated by plotting the forward I- V data on a log-log scale, which revealed two power-law regions with different exponents. In the lower voltage range, the exponent is approximately 1, implying that the charge transport mechanism is governed by Ohm's law. The charge transport mechanism in the higher voltage range, where the exponent varies between 1.1 and 1.7, is consistent with space-charge-limited (SCL) emission in the presence of shallow traps. The critical voltage ( Vc), which characterizes the onset of SCL conduction, decreases with increasing SWNT concentration. In addition, Vc was observed to increase with temperature. These initial results indicate that with further improvements in material consistency and reduction in defect densities, the polyaniline/single-walled carbon nanotube composite material can be used to fabricate organic electronic devices leading to many useful applications in microelectronics.

  19. Effect of nanosilica on optical, electric modulus and AC conductivity of polyvinyl alcohol/polyaniline films

    NASA Astrophysics Data System (ADS)

    El-Sayed, Somyia; Abel-Baset, Tarob; Elfadl, Azza Abou; Hassen, Arafa

    2015-05-01

    Nanosilica (NS) was synthesized by a sol-gel method and mixed with 0.98 polyvinyl alcohol (PVA)/0.02 polyaniline (PANI) in different amounts to produce nanocomposite films. High-resolution transmission electron microscopy (HR-TEM) revealed the average particle size of the NS to be ca. 15 nm. Scanning electron microscopy (SEM) showed that the NS was well-dispersed on the surface of the PVA/PNAI films. The Fourier transform infrared (FTIR) spectra of the samples showed a significant change in the intensity of the characteristic peak of the functional groups in the composite films with the amount of NS added. The absorbance and refractive index (n) of the composites were studied in the UV-vis range, and the optical energy band gap, Eg, and different optical parameters were calculated. The dielectric loss modulus, M″ and ac conductivity, σac, of the samples were studied within 300-425 K and 0.1 kHz-5 MHz, respectively. Two relaxation peaks were observed in the frequency dependence of the dielectric loss modulus, M″. The behavior of σac(f) for the composite films indicated that the conduction mechanism was correlated barrier hopping (CBH). The results of this work are discussed and compared with those of previous studies of similar composites.

  20. Processable Conducting Polyaniline, Carbon Nanotubes, Graphene and Their Composites

    NASA Astrophysics Data System (ADS)

    Wang, Kan

    Good processability is often required for applications of conducting materials like polyaniline (PANI), carbon nanotubes (CNTs) and graphene. This can be achieved by either physical stabilization or chemical functionalization. Functionalization usually expands the possible applications for the conducting materials depending on the properties of the functional groups. Processable conducting materials can also be combined with other co-dissolving materials to prepare composites with desired chemical and physical properties. Polyanilines (PANI) doped with dodecylbenzenesulfonic acid (DBSA) are soluble in many organic solvents such as chloroform and toluene. Single wall carbon nanotubes (SWCNTs) can be dispersed into PANI/DBSA to form homogeneous solutions. PANI/DBSA functions as a conducting surfactant for SWCNTs. The mixture can be combined with two-parts polyurethanes that co-dissolve in the organic solvent to produce conducting polymer composites. The composite mixtures can be applied onto various substrates by simple spray-on methods to obtain transparent and conducting coatings. Graphene, a single layer of graphite, has drawn intense interest for its unique properties. Processable graphene has been produced in N-methyl-2-pyrrolidone (NMP) by a one-step solvothermal reduction of graphite oxide without the aid of any reducing reagent and/or surfactant. The as-synthesized graphene disperses well in a variety of organic solvents such as dimethylsulfoxide (DMSO), ethanol and tetrahydrogenfuran (THF). The conductivity of solvothermal reduced graphite oxide is comparable to hydrazine reduced graphite oxide. Attempts were made to create intrinsically conducting glue comparable to mussel adhesive protiens using polyaniline and graphene. Mussels can attach to a variety of substrates under water. Catechol residue in 3,4-dihydroxyphenylalanine (L-DOPA) is the key to the wet adhesion. Tyrosine and phosphoserine with primary alkyl amine groups also participate in adhesion. A

  1. Polyaniline films and powders: Effect of excess dopant acid on conductivity

    SciTech Connect

    Feng, J.; MacDiarmid, A.G.

    1995-12-31

    We have shown previously that excess dopant acid, d,l camphorsulfonic acid, (HCSA), when present in a solution of m-cresol containing polyaniline doped with HCSA, reduces the conductivity of films of the doped polyaniline cast from the solution. We here report that the opposite effect is observed with powders of the same doped polyaniline. Polyaniline doped with HCSA was precipitated by pouring a solution of the doped polyaniline into excess hexane; it was then washed with either methanol or methanol containing HCSA to remove the m-cresol. The quantity of HCSA in the resulting dried powders was determined using TGA techniques. It was found that excess HCSA in the doped polyaniline increased the conductivity of compressed pellets of the polymer. The conductivity was increased from {approximately}4 S/cm (no excess HCSA) to {approximately}40 S/cm in material containing twice the amount of HCSA necessary for doping. The conductivity of {approximately}40 S/cm is the highest yet reported for doped polyaniline powders. Reasons for this increase conductivity will be presented.

  2. Electrical resistance response of polyaniline films to water, ethanol, and nitric acid solution

    NASA Astrophysics Data System (ADS)

    Yin, Hong-Xing; Li, Meng-Meng; Yang, H.; Long, Yun-Ze; Sun, Xin

    2010-08-01

    This paper reports on electrical resistance vs. aging time for the response of polyaniline films under exposure to water, ethanol and nitric acid (HNO3) solution. Camphor sulfonic acid-doped polyaniline films were prepared by a “doping-dedoping-redoping" method, the morphology and microstructures of the films were characterized by a scanning electron microscope and an x-ray diffractometer, the electrical resistance was measured by a four-probe method. It was found that a lower amount of water molecules infiltrating the film can decrease the film's resistance possibly due to an enhancement of charge carrier transfer between polyaniline chains, whereas excessive water molecules can swell inter-chain distances and result in a quick increase of resistance. The resistance of the film under exposure to ethanol increases and becomes much larger than the original value. However, HNO3 solution can decrease the film's resistance sharply possibly owing to doping effect of protonic acid. These results can help to understand the conduction mechanism in polyaniline films, and also indicate that the films have potential application in chemical sensors.

  3. Hierarchical graphene-polyaniline nanocomposite films for high-performance flexible electronic gas sensors.

    PubMed

    Guo, Yunlong; Wang, Ting; Chen, Fanhong; Sun, Xiaoming; Li, Xiaofeng; Yu, Zhongzhen; Wan, Pengbo; Chen, Xiaodong

    2016-06-01

    A hierarchically nanostructured graphene-polyaniline composite film is developed and assembled for a flexible, transparent electronic gas sensor to be integrated into wearable and foldable electronic devices. The hierarchical nanocomposite film is obtained via aniline polymerization in reduced graphene oxide (rGO) solution and simultaneous deposition on flexible PET substrate. The PANI nanoparticles (PPANI) anchored onto rGO surfaces (PPANI/rGO) and the PANI nanofiber (FPANI) are successfully interconnected and deposited onto flexible PET substrates to form hierarchical nanocomposite (PPANI/rGO-FPANI) network films. The assembled flexible, transparent electronic gas sensor exhibits high sensing performance towards NH3 gas concentrations ranging from 100 ppb to 100 ppm, reliable transparency (90.3% at 550 nm) for the PPANI/rGO-FPANI film (6 h sample), fast response/recovery time (36 s/18 s), and robust flexibility without an obvious performance decrease after 1000 bending/extending cycles. The excellent sensing performance could probably be ascribed to the synergetic effects and the relatively high surface area (47.896 m(2) g(-1)) of the PPANI/rGO-FPANI network films, the efficient artificial neural network sensing channels, and the effectively exposed active surfaces. It is expected to hold great promise for developing flexible, cost-effective, and highly sensitive electronic sensors with real-time analysis to be potentially integrated into wearable flexible electronics. PMID:27249547

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

    NASA Astrophysics Data System (ADS)

    Runge-Marchese, Jude Mary

    1997-10-01

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

  5. Silver nanowire/polyaniline composite transparent electrode with improved surface properties

    SciTech Connect

    Kumar, A.B.V. Kiran; Jiang, Jianwei; Bae, Chang Wan; Seo, Dong Min; Piao, Longhai Kim, Sang-Ho

    2014-09-15

    Highlights: • AgNWs/PANI transparent electrode was prepared by layer-by-layer coating method. • The surface roughness of the electrode reached to 6.5 nm (root mean square). • The electrode had reasonable sheet resistance (25 Ω/□) and transmittance (83.5%). - Abstract: Silver nanowires (AgNWs) are as potential candidates to replace indium tin oxide (ITO) in transparent electrodes because of their preferred conducting and optical properties. However, their rough surface properties are not favorable for the fabrication of optoelectronic devices, such as displays and thin-film solar cells. In the present investigation, AgNWs/polyaniline composite transparent electrodes with better surface properties were successfully prepared. AgNWs were incorporated into polyaniline:polystyrene sulfonate (PANI:PSS) by layer-by-layer coating and mechanical pressing. PANI:PSS decreased the surface roughness of the AgNWs electrode by filling the gap of the random AgNWs network. The transparent composite electrode had decreased surface roughness (root mean square 6.5 nm) with reasonable sheet resistance (25 Ω/□) and transmittance (83.5%)

  6. Conducting polymer composite film incorporated with aligned carbon nanotubes for transparent, flexible and efficient supercapacitor

    PubMed Central

    Lin, Huijuan; Li, Li; Ren, Jing; Cai, Zhenbo; Qiu, Longbin; Yang, Zhibin; Peng, Huisheng

    2013-01-01

    Polyaniline composite films incorporated with aligned multi-walled carbon nanotubes (MWCNTs) are synthesized through an easy electrodeposition process. These robust and electrically conductive films are found to function as effective electrodes to fabricate transparent and flexible supercapacitors with a maximum specific capacitance of 233 F/g at a current density of 1 A/g. It is 36 times of bare MWCNT sheet, 23 times of pure polyaniline and 3 times of randomly dispersed MWCNT/polyaniline film under the same conditions. The novel supercapacitors also show a high cyclic stability. PMID:23443325

  7. Composite membranes prepared from cation exchange membranes and polyaniline and their transport properties in electrodialysis

    SciTech Connect

    Sata, Tshikatsu; Ishii, Yuuko; Kawamura, Kohei; Matsusaki, Koji

    1999-02-01

    A cation exchange membrane was modified with polyaniline by polymerizing aniline with ammonium peroxodisulfate on the membrane surfaces, producing a membrane with polyaniline layers on both surfaces or a membrane with a single polyaniline layer on the surface. The modified membranes, composite membranes, showed sodium ion permselectivity in electrodialysis compared with divalent cations at an optimum polymerization time. The electronic conductivity of dry membranes showed a maximum (ca. 5 {times} 10{sup {minus}3} S/cm) at the same polymerization time as the time to attain a maximum value of the sodium ion permselectivity. Because emeraldine-based polyaniline is conductive and has a cationic charge, the sodium ion permselectivity is based on the difference in the electrostatic repulsion forces of the cationic charge on the membrane surface of a desalting side to divalent cations and sodium ions. In fact, the selective permeation of sodium ions appeared only when the layer faced the desalting side of the membrane, and was affected by dissociation of polyaniline. Further oxidized polyaniline, pernigraniline-based polyaniline, did not affect the permselectivity between cations, and the diffusion coefficient of neutral molecules, urea, increased with increasing polymerization time. Sodium ion permselectivity was maintained with repeated electrodialysis.

  8. Structural, optical and electrical properties of CdS–polyaniline Langmuir–Blodgett films

    SciTech Connect

    Das, Nayan Mani Roy, Dhrubojyoti Gupta, P. S.; Gupta, M.; Ganesan, V.

    2014-04-24

    Structural, optical and electrical properties study of the cadmium sulphide (CdS) incorporated polyaniline (PANI) thin films with varying layers have been carried out. It is seen that layer variation enhances the particle mean sizes with quenching of photoluminescence and an increase in rectifying nature of current-voltage measurements.

  9. Ultrathin film composite membrane separation of CO2 from natural gas. Final report, April 1, 1992-March 31, 1993

    SciTech Connect

    Martin, C.R.

    1993-09-01

    Investigations of the rate and selectivity of gas transport in the electronically conductive polymer polyaniline are described. Both rate and selectivity were found to be dependent on doping level. Permeability coefficients for all gases studied decreased with increasing doping level, and selectivity coefficients, in general, increased with doping level. The effects of other variables, including nature of the counterion and temperature and duration of thermal processing of the film, were also explored. Both free-standing polyaniline films (ca 25 micrometers thick) and thin film composite membranes based on polyaniline were studied. The thin film composites were prepared by coating the polyaniline film (ca. 3 micrometers thick) onto the surface of a microporous alumina support membrane. The free-standing and thin film composite membranes showed identical rates and selectivities of gas-transport.

  10. Facile preparation of hierarchical polyaniline-lignin composite with a reactive silver-ion adsorbability.

    PubMed

    He, Zhi-Wei; Lü, Qiu-Feng; Zhang, Jia-Yin

    2012-01-01

    A hierarchical polyaniline-lignin (PANI-EHL) composite was facilely prepared from aniline and enzymatic hydrolysis lignin in an aqueous solution of ammonia. The morphology, FTIR, UV-vis spectra, thermogravimetric analysis, and wide-angle X-ray diffraction analyses of the composite were systematically investigated. Furthermore, the sorption property of the PANI-EHL composite for silver ions in aqueous solution was studied via a static sorption technique. The result demonstrated that the PANI-EHL composite possessed a strongly reactive sorption characteristic for silver ions. Serrated silver threads with length up to 10 mm were obtained by using the PANI-EHL composite as a low-cost adsorbent. Moreover, the role of EHL and polyaniline in the PANI-EHL composite for silver ions sorption was investigated. The investigation indicated that the EHL unit could play a vital role in the chelation of silver ions, whereas the polyaniline unit played a leading role in redox sorption.

  11. Prevention of corrosion with polyaniline

    NASA Technical Reports Server (NTRS)

    MacDiarmid, Alan G. (Inventor); Ahmad, Naseer (Inventor)

    1997-01-01

    Methods for improving the corrosion inhibition of a metal or metal alloy substrate surface are provided wherein the substrate surface is coated with a polyaniline film. The polyaniline film coating is applied by contacting the substrate surface with a solution of polyaniline. The polyaniline is dissolved in an appropriate organic solvent and the solvent is allowed to evaporate from the substrate surface yielding the polyaniline film coating.

  12. Large-area electrochromic coatings: Composites of polyaniline and polyacrylate-silica hybrid sol-gel materials

    SciTech Connect

    Jang, G.W.; Chen, C.; Gumbs, R.W.; Wei, Y.; Yeh, J.M.

    1996-08-01

    A low-cost technique for fabricating large-area electrochromic coatings is described. Polyaniline was incorporated into polyacrylate-silica hybrid sol-gel networks using suspended particles or solutions. A solution of polyaniline and poly[methyl methacrylate-co-3-(trimethoxysilyl)propyl methacrylate] can be spray- or brush-coated on transparent indium-tin oxide substrates to form robust electrochromic coatings. Silane functional groups on the polyacrylate chain act as coupling and cross-linking agents to improve surface adhesion and mechanical properties of the resulting composite coatings. These coatings showed reversible transparent to green color change when polarized at potentials between {minus}0.4 and +0.4 V vs. Ag/AgCl in a 0.2 M LiClO{sub 4}/acetonitrile electrolyte solution. The cycle lifetimes of polyaniline films were improved by incorporating the polymer in the polyacrylate-silica matrix. Electrochromic switching was demonstrated for the composite coatings in large-area all-solid-state devices.

  13. Comparison of chemically and electrochemically prepared polyaniline films. 2. Optical properties

    SciTech Connect

    Chinn, D.; DuBow, J.; Josowicz, M.

    1995-08-01

    Relaxation phenomena in thin polyaniline films synthesized chemically and electrochemically are investigated by UV-vis and IR spectroscopy. It is shown that the relaxation process carried out from the electrochemically oxidized or electrochemically reduced states of the polyaniline always proceeds toward the emeraldine state. The relaxation process in acid is governed by disproportionation and formation of semiquinone radicals. The changes in the population density of the polaronic states within the polaronic band allows determination of the change in the oxidation state and consequently the change in the position of the Fermi energy level. The formation of polaronic states is ascertained by diffusion of ions from or into the polyaniline matrix in solution and within the polymer in air. 40 refs., 11 figs., 1 tab.

  14. Hierarchical graphene-polyaniline nanocomposite films for high-performance flexible electronic gas sensors

    NASA Astrophysics Data System (ADS)

    Guo, Yunlong; Wang, Ting; Chen, Fanhong; Sun, Xiaoming; Li, Xiaofeng; Yu, Zhongzhen; Wan, Pengbo; Chen, Xiaodong

    2016-06-01

    A hierarchically nanostructured graphene-polyaniline composite film is developed and assembled for a flexible, transparent electronic gas sensor to be integrated into wearable and foldable electronic devices. The hierarchical nanocomposite film is obtained via aniline polymerization in reduced graphene oxide (rGO) solution and simultaneous deposition on flexible PET substrate. The PANI nanoparticles (PPANI) anchored onto rGO surfaces (PPANI/rGO) and the PANI nanofiber (FPANI) are successfully interconnected and deposited onto flexible PET substrates to form hierarchical nanocomposite (PPANI/rGO-FPANI) network films. The assembled flexible, transparent electronic gas sensor exhibits high sensing performance towards NH3 gas concentrations ranging from 100 ppb to 100 ppm, reliable transparency (90.3% at 550 nm) for the PPANI/rGO-FPANI film (6 h sample), fast response/recovery time (36 s/18 s), and robust flexibility without an obvious performance decrease after 1000 bending/extending cycles. The excellent sensing performance could probably be ascribed to the synergetic effects and the relatively high surface area (47.896 m2 g-1) of the PPANI/rGO-FPANI network films, the efficient artificial neural network sensing channels, and the effectively exposed active surfaces. It is expected to hold great promise for developing flexible, cost-effective, and highly sensitive electronic sensors with real-time analysis to be potentially integrated into wearable flexible electronics.A hierarchically nanostructured graphene-polyaniline composite film is developed and assembled for a flexible, transparent electronic gas sensor to be integrated into wearable and foldable electronic devices. The hierarchical nanocomposite film is obtained via aniline polymerization in reduced graphene oxide (rGO) solution and simultaneous deposition on flexible PET substrate. The PANI nanoparticles (PPANI) anchored onto rGO surfaces (PPANI/rGO) and the PANI nanofiber (FPANI) are successfully

  15. Photocatalysis and wave-absorbing properties of polyaniline/TiO 2 microbelts composite by in situ polymerization method

    NASA Astrophysics Data System (ADS)

    Li, Qiaoling; Zhang, Cunrui; Li, Jianqiang

    2010-11-01

    Polyaniline (PANI)/TiO 2 composite is prepared by in situ polymerization of polyaniline on the surface of TiO 2 template obtained by the sol-gel process via cotton template. The TiO 2 microbelts are prepared by sol-gel method using the absorbent cotton as template for the first time. Then the TiO 2 microtubules are used as template for the preparation of polyaniline/TiO 2 composites. The structure, morphology and properties of the composites are characterized with scanning electron microscope (SEM), IR, Net-wok Analyzer. A possible formation mechanism of TiO 2 microtubules and polyaniline/TiO 2 composites has been proposed. The effect of the mol ratio of polyaniline/TiO 2 on the microwave loss properties and photocatalysis properties of the composites is investigated.

  16. Polyaniline coated cellulose fiber / polyvinyl alcohol composites with high dielectric permittivity and low percolation threshold

    NASA Astrophysics Data System (ADS)

    Anju, V. P.; Narayanankutty, Sunil K.

    2016-01-01

    Cost effective, high performance dielectric composites based on polyvinyl alcohol, cellulose fibers and polyaniline were prepared and the dielectric properties were studied as a function of fiber content, fiber dimensions and polyaniline content over a frequency range of 40 Hz to 30 MHz. The short cellulose fibers were size-reduced to micro and nano levels prior to coating with polyaniline. Fiber surface was coated with Polyaniline (PANI) by an in situ polymerization technique in aqueous medium. The composites were then prepared by solution casting method. Short cellulose fiber composites showed a dielectric constant (DEC) of 2.3 x 105 at 40 Hz. For the micro- and nano- cellulose fiber composites the DEC was increased to 4.5 x 105 and 1.3 x 108, respectively. To gain insight into the inflection point of the dielectric data polynomial regression analysis was carried out. The loss tangent of all the composites remained at less than 1.5. Further, AC conductivity, real and imaginary electric moduli of all the composites were evaluated. PVA nanocomposite attained an AC conductivity of 3 S/m. These showed that by controlling the size of the fiber used, it was possible to tune the permittivity and dielectric loss to desired values over a wide range. These novel nanocomposites, combining high dielectric constant and low dielectric loss, can be effectively used in applications such as high-charge storage capacitors.

  17. Two liquid adsorptive entrapment of a pluronic polymer into the surface of polyaniline films.

    PubMed

    Li, Z F; Ruckenstein, E

    2003-08-15

    Pluronic triblock copolymers were entrapped on the surface of polyaniline (PANI) films by first immersing the latter in N-methylpyrrolidinone (NMP) solutions of one of the Pluronics for a short time. This softened the surface of the films and allowed the Pluronic molecules to entangle with PANI segments of the swollen film on the surface. Further, the films were taken out from the NMP solution and dipped into water, which is a nonsolvent for PANI. The rapid surface deswelling of PANI by the water resulted in the entrapment of the Pluronic on its surface, with the hydrophilic blocks toward water and the hydrophobic block imbedded in the PANI films. The modified PANI obtained was examined by X-ray photoelectron spectroscopy, water droplets contact angles, scanning electron microscopy, and wide angle X-ray diffraction. The surface of the Pluronic entrapped PANI films became more hydrophilic than the hydrophobic PANI films and decreased the amount of bovine serum albumin protein adsorbed on them. This means that, by reducing the biofouling, the life of the modified polyaniline film can be extended when the latter is employed as a biosensor.

  18. Enhancement of photoelectric catalytic activity of TiO{sub 2} film via Polyaniline hybridization

    SciTech Connect

    Wang Yajun; Xu Jing; Zong Weizheng; Zhu Yongfa

    2011-06-15

    A Polyaniline (PANI)/TiO{sub 2} film coated on titanium foil was successfully prepared using the sol-gel method followed by a facile chemisorption. Compared with pristine TiO{sub 2}, the photocatalytic (PC) and photoelectrocatalytic (PEC) degradation rates of 2,4-dichlorophenol (2,4-DCP) with the PANI/TiO{sub 2} film were enhanced by 22.2% and 57.5%, respectively. 2,4-DCP can be mineralized more effectively in the presence of PANI/TiO{sub 2} film. The best PEC degradation efficiency of 2,4-DCP with the PANI/TiO{sub 2} film was acquired at an external potential of 1.5 V with a layer of 1 nm thick PANI. The PANI/TiO{sub 2} film was characterized by Raman spectra, Fourier transform infrared spectra (FT-IR), Auger electron spectroscopy (AES), and electrochemical analysis. These results indicated that there was a chemical interaction on the interface of PANI and TiO{sub 2}. This interaction may be of significance to promote the migration efficiency of carriers and induce a synergetic effect to enhance the PC and PEC activities. - Graphical abstract: The effect of PANI content on 2,4-DCP degradation with initial concentration of 50 mg/L, external potential=1.5 V. Inset: degradation rate constants of various PANI/TiO{sub 2} films. Highlights: > Polyaniline/TiO{sub 2} film was prepared using the sol-gel method followed by chemisorption. > Photoelectrocatalytic degradation rate of 2,4-dichlorophenol was enhanced by 57.5%. > The modification of Polyaniline to TiO{sub 2} film caused a rapid charge separation. > Best degradation efficiency was acquired at 1.5 V with 1 nm thick PANI.

  19. Improved surface properties of polyaniline films by blending with Pluronic polymers without the modification of the other characteristics.

    PubMed

    Li, Z F; Ruckenstein, E

    2003-08-15

    Films of conductive polyaniline and amphiphilic Pluronic (P105) copolymer blends were prepared by dissolving the two polymers in N-methylpyrrolidinone (NMP) followed by a slow solvent evaporation at 55 degrees C. The characteristics of both doped and undoped films were determined by X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), water droplet contact angles, differential scanning calorimetry (DSC), thermal gravimetry analysis (TG), wide-angle X-ray diffraction (WAXD), and tensile strength measurements. The surface of the blends became more hydrophilic than that of the hydrophobic PANI film, but the other properties of the blends did not change appreciably for Pluronic content lower than 50 wt%. Compared to PANI films, the more hydrophilic surfaces decreased the amount of bovine serum albumin protein adsorbed. By preventing biofouling, the polyaniline-Pluronic blends can become more useful as biosensors than the polyaniline films.

  20. Drop-casted polyaniline thin films on flexible substrates for supercapacitor applications

    NASA Astrophysics Data System (ADS)

    Kim, Jongmin; Sohn, J.; Jo, Yongcheol; Woo, Hyeonseok; Han, Jaeseok; Cho, Sangeun; Inamdar, A. I.; Kim, Hyungsang; Im, Hyunsik

    2014-11-01

    The PANI (polyaniline) thin films are synthesized on flexible ITO/PET (indium tin oxide/polyethylene terephthalate) substrates by using the drop-casting method. The amount of the PANI for the drop casting varies from 0.04 to 0.16 g. The morphology of the drop-casted PANI films shows a porous vermicular shape. The electrochemical supercapacitor properties of the PANI films are examined in a 0.5-M LiClO4 + PC electrolyte. The PANI films with 0.08 g of PANI show higher current density and considerably higher specific capacitance and capacity retention, compared with other PANI films. The highest specific capacitance of the films with 0.08 g of PANI is found to be ˜120 F/g, and the capacity retention is found to be as high as 70.51% after 100 charge-discharge cycles.

  1. A spectroelectrochemical study on single-oscillator model and optical constants of sulfonated polyaniline film.

    PubMed

    Caglar, Mujdat; Ilican, Saliha; Caglar, Yasemin; Sahin, Yücel; Yakuphanoglu, Fahrettin; Hür, Deniz

    2008-11-15

    The optical properties of sulfonated polyaniline (SPAN) thin film prepared by electrochemical method have been investigated. Polychromic behavior of SPAN thin film (transparent yellow-green-dark blue) was observed when the cyclic voltammograms were taken between -0.25 V and +1.90 V (vs. Ag/AgCl, sat.) during the growth of polyaniline film. In situ UV-vis spectra of the polymers-indium tin oxide (ITO) glass electrode were taken during the oxidation of the polymers at different applied potentials. The direct band gap values of SPAN thin film changed from 3.771 eV to 3.874 eV with the applied potentials. From in situ UV-vis spectra, the optical constants such as refractive index and dielectric constant of the SPAN thin film were determined. The important changes in absorption edge, refractive index and the dielectric constant were observed due to the applied potentials. The refractive index dispersion curves of the film obey the single-oscillator model and oscillator parameters changed with the applied potentials. The most significant result of the present work is in situ spectroelectrochemical method, which can be used to modify the optical band gaps and constants. PMID:18337162

  2. Polyaniline/Carbon Nanotube Composite Fiber-Based Dye-Sensitized Photovoltaic Wire.

    PubMed

    Pan, Shaowu; Yang, Jinhu

    2015-09-01

    Polyaniline/carbon nanotube composite fiber was prepared from aligned multi-walled carbon nano- tube fiber coupling with subsequent electrochemical polymerization of aniline. Novel wire-shaped dye-sensitized solar cells were obtained by using the composite fiber as counter electrode. Photovoltaic wire based on the composite fiber showed a conversion efficiency of 3.8%, which is 63% higher than the pure carbon nanotube fiber. PMID:26716346

  3. Polyaniline films photoelectrochemically reduce CO2 to alcohols.

    PubMed

    Hursán, Dorottya; Kormányos, Attila; Rajeshwar, Krishnan; Janáky, Csaba

    2016-07-01

    In this communication, we demonstrate that polyaniline, the very first example of an organic semiconductor, is a promising photocathode material for the conversion of carbon dioxide (CO2) to alcohol fuels. CO2 is a greenhouse gas; thus using solar energy to convert CO2 to transportation fuels (such as methanol or ethanol) is a value-added approach to simultaneous generation of alternative fuels and environmental remediation of carbon emissions. Insights into its unique behavior obtained from photoelectrochemical measurements and adsorption studies, together with spectroscopic data, are presented. Through a comparative study involving various conducting polymers, a set of criteria is developed for an organic semiconductor to function as a photocathode for generation of solar fuels from CO2. PMID:27345191

  4. Efficient photocatalytic decolorization of some textile dyes using Fe ions doped polyaniline film on ITO coated glass substrate.

    PubMed

    Haspulat, Bircan; Gülce, Ahmet; Gülce, Handan

    2013-09-15

    In this study, the photocatalytic decolorization of four commercial textile dyes with different structures has been investigated using electrochemically synthesized polyaniline and Fe ions doped polyaniline on ITO coated glass substrate as photocatalyst in aqueous solution under UV irradiation for the first time. Scanning electron microscopy, atomic force microscopy, FT-IR spectra, UV-vis spectroscopy measurements were used to characterize the electrochemically synthesized polymer film photocatalyst. Film hydrophilicity was assessed from contact angle measurements. The results show that both of the polymer films exhibit good photocatalytic performance. Surprisingly, it was determined that by using Fe(II) ions during polymerization, it is possible to modify the surface roughness and wettability of the produced polyaniline films which favors their photocatalytic activity in water-based solutions. All four of the used dyes (methylene blue, malachite green, methyl orange and methyl red) were completely decolorizated in 90 min of irradiation under UV light by using Fe ions doped polyaniline at the dye concentration of 1.5 × 10(-5)M, while the decolorization of those dyes were between 43% and 83% by using polyaniline as photocatalyst. Hence, it may be a viable technique for the safe disposal of textile wastewater into waste streams.

  5. Temperature dependent thermoelectric property of reduced graphene oxide-polyaniline composite

    NASA Astrophysics Data System (ADS)

    Mitra, Mousumi; Banerjee, Dipali; Kargupta, Kajari; Ganguly, Saibal

    2016-05-01

    A composite material of reduced graphene oxide (rG) nanosheets with polyaniline (PANI) protonated by 5-sulfosalicylic acid has been synthesized via in situ oxidative polymerization method. The morphological and spectral characterizations have been done using FESEM and XRD measurements. The thermoelectric (TE) properties of the reduced graphene oxide-polyaniline composite (rG-P) has been studied in the temperature range from 300-400 K. The electrical conductivity and the Seebeck coefficient of rG-P is higher than the of pure PANI, while the thermal conductivity of the composite still keeps much low value ensuing an increase in the dimensionless figure of merit (ZT) in the whole temperature range.

  6. Structural organization of films based on polyaniline/polysulfonic acid complexes depending on the synthesis method

    SciTech Connect

    Simagina, L. V. Gaynutdinov, R. V.; Stepina, N. D.; Sorokina, K. L.; Morozova, O. V.; Shumakovich, G. P.; Yaropolov, A. I.; Tolstikhina, A. L.

    2010-07-15

    The optical properties and morphology of complexes based on polyaniline (PANI) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS), depending on their synthesis conditions, have been characterized by UV-visible spectroscopy and atomic force microscopy. The dependence of the electron absorption spectra of PANI/PAMPS complexes and the surface topography of their films on the initiation way of PANI formation (chemical and enzymatic) and the use of promoters of aniline polymerization has been investigated. The aniline polymerization kinetics with and without polymerization promoters has been studied. All PANI/PAMPS complexes are found to have a nanocomposite time-stable structure.

  7. Third-order nonlinear optical properties of undoped polyaniline solutions and films probed at 532 nm

    SciTech Connect

    Maciel, Glauco S.; Bezerra, Arandi G.; Rakov, Nikifor; de Araujo, Cid B.; Gomes, Anderson S. L.; de Azevedo, Walter M.

    2001-08-01

    The third-order nonlinear optical properties of polyaniline (PANI) solutions and films were investigated at 532 nm by use of Z-scan, power limiting, and optical Kerr gate techniques. The polymers studied were the undoped partially oxidized (emeraldine base) and fully reduced (leucoemeraldine base) forms of PANI. Our results demonstrate that the leucoemeraldine base is more suitable for use in devices such as all-optical switches and optical power limiters operating at 532 nm. The worse performance of the emeraldine base is due to the presence of defects inside the bandgap of the polymer. {copyright} 2001 Optical Society of America

  8. Dual-shell hollow polyaniline/sulfur-core/polyaniline composites improving the capacity and cycle performance of lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    An, Yanling; Wei, Pan; Fan, Meiqiang; Chen, Da; Chen, Haichao; Ju, QiangJian; Tian, Guanglei; Shu, Kangying

    2016-07-01

    In this study, a dual-shell hollow polyaniline/sulfur-core/polyaniline (hPANI/S/PANI) composite was prepared by successively depositing PANI, S, and PANI on the surface of a template silicon sphere. The electrochemical properties of this composite were evaluated using a lithium plate as an anode in lithium/sulfur cells. The hPANI/S/PANI composite showed a discharge capacity of 572.2 mAh g-1 after 214 cycles at 0.1 C, and the Coulombic efficiency was above 87% in the whole charge/discharge cycle. The improved cycle property of the hPANI/S/PANI composite can be ascribed to the fine sulfur particles homogeneously deposited on the PANI surface and sprawled inside the two PANI layers during the charge/discharge cycle. This behavior stabilized the nanostructure of sulfur and enhanced its conductivity.

  9. Oxidation and sensing of ascorbic acid and dopamine on self-assembled gold nanoparticles incorporated within polyaniline film

    NASA Astrophysics Data System (ADS)

    Chu, Wenya; Zhou, Qun; Li, Shuangshuang; Zhao, Wei; Li, Na; Zheng, Junwei

    2015-10-01

    Electrochemical biosensors based on conducting polymers incorporated with metallic nanoparticles can greatly enhance sensitivity and selectivity. Herein, we report a facile fabrication approach for polyaniline (PAN) incorporated with a gold nanoparticle (AuNP) composite electrode by electrodeposition of PAN on a self-assembled AuNP layer on the surface of an indium tin oxide electrode. The resulting AuNP/PAN composite electrode exhibits a remarkable synergistic effect on the electrocatalytic oxidation of ascorbic acid (AA) and dopamine (DA). It is demonstrated that the oxidation reaction of AA mainly occurs at AuNPs inside the PAN film as the ascorbate anions are doped into the polymer during the oxidation of the PAN film. Conversely, the oxidation of positively charged DA may only take place at the PAN/solution interface. The different mechanisms of the electrode reactions result in the oxidation of AA and DA occurring at different potentials. As a result, the AuNP/PAN composite electrode can be employed to simultaneously detect AA and DA with a good linear range, high sensitivity, and low detection limit.

  10. [Low-Concentration CO₂ Adsorption on Polyaniline/Zeolite Y Composites].

    PubMed

    Liu, Feng-lin; Lu, Xia; Zhang, Hui; Ge, Xin; Liu, Jie; Zhang, Yong-zhen

    2015-12-01

    Three polyaniline (PANI)/zeolite Y composites with different polyaniline loads, PANI-Y-1, PANI-Y-2 and PANI-Y-3, were prepared by in situ chemical oxidation polymerization method using different amounts of aniline. The structural characteristics of these materials were analyzed by FT-IR and nitrogen adsorption experiment. The adsorption and regeneration properties of the composites for low-concentration CO₂ at atmosphere pressure were investigated. Characterization results show that aniline is successfully polymerized in and out side of channels of zeolite Y. The above three materials, whose pores are composed of macropores and mesopores, have specific surface areas of 52, 54 and 35 m2 g -¹, respectively. In addition, a composite with high polyaniline loading has low pore volumes. At 20°C, CO₂ adsorption on the three composites and zeolite Y are well fitted with the Logistic model, and the adsorption amount of CO₂ with initial concentration of 10% follows an order of PANI-Y-2 (2.09 mmol · g⁻¹) > PANI-Y-3 (1.79 mmol · g⁻¹) > PANI-Y-l (1.07 mmol · g⁻¹) > zeolite Y (0.80 mmol · g⁻¹. The adsorption order of the composites is the result of combined effects from polyaniline amount and specific surface area of adsorbents. With concentrations ranging between 2% and 10% CO2 adsorption amount increases when initial concentration is raised. With adsorption temperature changing from 25° to 6°C, low temperature is advantageous to enhancing CO₂ adsorption. For PANI-Y-2, only a low regeneration efficiency of 68% is obtained after four times thermal desorption at 80°C. However, the regeneration efficiency could be increased up to 94% by aqueous ammonia combined with thermal treatment method.

  11. [Low-Concentration CO₂ Adsorption on Polyaniline/Zeolite Y Composites].

    PubMed

    Liu, Feng-lin; Lu, Xia; Zhang, Hui; Ge, Xin; Liu, Jie; Zhang, Yong-zhen

    2015-12-01

    Three polyaniline (PANI)/zeolite Y composites with different polyaniline loads, PANI-Y-1, PANI-Y-2 and PANI-Y-3, were prepared by in situ chemical oxidation polymerization method using different amounts of aniline. The structural characteristics of these materials were analyzed by FT-IR and nitrogen adsorption experiment. The adsorption and regeneration properties of the composites for low-concentration CO₂ at atmosphere pressure were investigated. Characterization results show that aniline is successfully polymerized in and out side of channels of zeolite Y. The above three materials, whose pores are composed of macropores and mesopores, have specific surface areas of 52, 54 and 35 m2 g -¹, respectively. In addition, a composite with high polyaniline loading has low pore volumes. At 20°C, CO₂ adsorption on the three composites and zeolite Y are well fitted with the Logistic model, and the adsorption amount of CO₂ with initial concentration of 10% follows an order of PANI-Y-2 (2.09 mmol · g⁻¹) > PANI-Y-3 (1.79 mmol · g⁻¹) > PANI-Y-l (1.07 mmol · g⁻¹) > zeolite Y (0.80 mmol · g⁻¹. The adsorption order of the composites is the result of combined effects from polyaniline amount and specific surface area of adsorbents. With concentrations ranging between 2% and 10% CO2 adsorption amount increases when initial concentration is raised. With adsorption temperature changing from 25° to 6°C, low temperature is advantageous to enhancing CO₂ adsorption. For PANI-Y-2, only a low regeneration efficiency of 68% is obtained after four times thermal desorption at 80°C. However, the regeneration efficiency could be increased up to 94% by aqueous ammonia combined with thermal treatment method. PMID:27011973

  12. Ceramic Composite Thin Films

    NASA Technical Reports Server (NTRS)

    Ruoff, Rodney S. (Inventor); Stankovich, Sasha (Inventor); Dikin, Dmitriy A. (Inventor); Nguyen, SonBinh T. (Inventor)

    2013-01-01

    A ceramic composite thin film or layer includes individual graphene oxide and/or electrically conductive graphene sheets dispersed in a ceramic (e.g. silica) matrix. The thin film or layer can be electrically conductive film or layer depending the amount of graphene sheets present. The composite films or layers are transparent, chemically inert and compatible with both glass and hydrophilic SiOx/silicon substrates. The composite film or layer can be produced by making a suspension of graphene oxide sheet fragments, introducing a silica-precursor or silica to the suspension to form a sol, depositing the sol on a substrate as thin film or layer, at least partially reducing the graphene oxide sheets to conductive graphene sheets, and thermally consolidating the thin film or layer to form a silica matrix in which the graphene oxide and/or graphene sheets are dispersed.

  13. Synthesis, characterization of polyaniline/BaFe 12O 19 composites with microwave-absorbing properties

    NASA Astrophysics Data System (ADS)

    Ting, Tzu-Hao; Wu, Kuo-Hui

    2010-08-01

    Polyaniline/BaFe 12O 19 (PANI/Ba ferrite) composites were synthesized by in situ polymerization at different aniline/Ba ferrite weight ratios (Ani/Ba ferrite=1/2, 1/1 and 2/1) and introduced into epoxy resin to be microwave absorber. The spectroscopic characterizations of the formation processes of PANI/Ba ferrite composites were studied using Fourier transform infrared, ultraviolet-visible spectrophotometer, X-ray diffraction, scanning electron microscopy, transmission electron microscopy and electron spin resonance. Microwave-absorbing properties were investigated by measuring complex permittivity, complex permeability and reflection loss in the 2-18 and 18-40 GHz microwave frequency range using the free space method. The results showed that a wider absorption frequency range could be obtained by adding different polyaniline contents in Ba ferrite.

  14. Electrorheological Response of POLYANILINE-TIO2 Composite Suspensions

    NASA Astrophysics Data System (ADS)

    Sung, J. H.; Lee, I.; Choi, H. J.; Choi, S. B.

    As an organic/inorganic hybrid possessing advantages from the combination of their own unique properties, conducting polyaniline (PANI)-titanium dioxide (TiO2) hybrid particles were synthesized by an oxidation polymerization of aniline, and their ER characteristics were examined. Our aim was to study the ER behavior of highly potential ER-active particles using conducting polymer and TiO2 nanoparticle with relatively high dielectric constant. In addition, we also investigated its ER behavior as a function of particle fraction of TiO2 under an applied electric field. The result was interpreted in terms of the dielectric relaxation mismatch. The fast relaxation time of PANI/TiO2 hybrid was considered to enhance electrostatic force over shear force under a hydrodynamic flow, showing its improved ER performance.

  15. Increasing the high-frequency magnetic permeability of MnZn ferrite in polyaniline composites by incorporating silver

    NASA Astrophysics Data System (ADS)

    Babayan, V.; Kazantseva, N. E.; Sapurina, I.; Moučka, R.; Stejskal, J.; Sáha, P.

    2013-05-01

    A hybrid composite containing 73 vol% of MnZn ferrite, 21 vol% of polyaniline, and 6 vol% of silver is obtained by oxidative polymerization of aniline with silver nitrate in the presence of ferrite powder. The hybrid composite contains ferrite particles with a size of 40-80 μm coated by an inhomogeneous layer of polyaniline in the conducting emeraldine form. Silver in the form of nano- and submicrometre -size particles is localized both on the surface of ferrite particles and in the bulk of polyaniline coating. The electrical and magnetic properties of the hybrid composite are investigated and compared with the properties of a composite with 71 vol% of MnZn ferrite coated by a conducting polyaniline layer (29 vol%). The hybrid composite containing silver exhibits an increase in the real and imaginary parts of the complex permeability in the radio-frequency band by more than one and a half times compared with those of the MnZn ferrite-polyaniline composite. The high-frequency permittivity of both composites is determined by the properties of core-shell structure: electric properties of shell as well as its composition and uniformity.

  16. An Amperometric Biosensor for Glucose Determination Prepared from Glucose Oxidase Immobilized in Polyaniline-Polyvinylsulfonate Film

    PubMed Central

    Arslan, Fatma; Ustabaş, Selvin; Arslan, Halit

    2011-01-01

    In this study, a novel amperometric glucose biosensor with immobilization of glucose oxidase on electrochemically polymerized polyaniline-polyvinylsulphonate (Pani-Pvs) films has been accomplished via the entrapment technique. Electropolymerization of aniline on the Pt surface of the Pt electrode was carried out at constant potential (0.75 V, vs. Ag/AgCl) using an electrochemical cell containing aniline and polyvinylsulphonate. Firstly, the optimum working conditions for preparing polyaniline-polyvinylsulfonate films were investigated. Determination of glucose was carried out by the oxidation of enzymatically produced H2O2 at 0.4 V vs. Ag/AgCl. The effects of pH and temperature were investigated and the optimum pH value was found to be 7.5. The storage stability and operational stability of the enzyme electrode were also studied. The results show that 75% of the response current was retained after 16 activity assays. The prepared glucose biosensor retained 80.6% of initial activity after 40 days when stored in 0.1 M phosphate buffer solution at 4 °C. PMID:22164068

  17. Thin film composite actuators

    NASA Astrophysics Data System (ADS)

    Su, Quanmin; Kim, Taesung; Zheng, Yun; Wuttig, Manfred R.

    1995-05-01

    The mechanical properties of Ni50Ti50 deposited on Si substrates were studied focussing on the interaction of the film and substrate. This interaction determines the transformation characteristics through interface accommodation and mechanical constraints exerted by the substrate stiffness. Substrate stiffness, controlled by the film/substrate thickness ratio, was found to have a substantial influence on the output energy of the film/substrate composite. A switch type composite based on this knowledge was fabricated and tested. The thermo-mechanical properties of Terfenol-D thin films deposited on Si substrates were studied by static and dynamic measurements of film/substrate composite cantilevers. The Curie transition, (Delta) E effect and mechanical damping of the film were measured simultaneously. The stress in the film was controlled by annealing below the recrystallization temperature and determined to vary from -500 MPa, compression, in as deposited films to +480 MPa, tension, in annealed films. The Curie temperature shifts from 80 degree(s)C to 140 degree(s)C as the tension increases while the structure of the film remains amorphous. The stress change induced by annealing also drastically effects the film's damping characteristics. The (Delta) E effect of the amorphous material, about 20%, was used to estimate the magnetostriction, (lambda) s approximately equals 4 (DOT) 10-3.

  18. Preparation and Electrical Characterization of Poly(Aniline) NanoClay Composites

    NASA Astrophysics Data System (ADS)

    Ahlatcioǧlu, Esma; şenkal, Bahire Filiz; Okutan, Mustafa

    2015-07-01

    In this work, synthesis and characterization of composite materials based on NanoClay(NC) and boric acid doped PolyAniline (PANI) is studied. PANI was successfully incorporated into NC to form PANI-NC composites. The resulting organic-inorganic hybrid material, PANI-NC was characterized by various physicochemical techniques. Formation of PANI inside the clay tactoid has been confirmed by X-ray diffraction studies (XRD), scanning electron microscope (SEM) and FT-IR. Also, conductivity and physical properties of the PANI-NC composites were investigated.

  19. DC magnetron sputtered polyaniline-HCl thin films for chemical sensing applications.

    PubMed

    Menegazzo, Nicola; Boyne, Devon; Bui, Holt; Beebe, Thomas P; Booksh, Karl S

    2012-07-01

    Thin films of conducting polymers exhibit unique chemical and physical properties that render them integral parts in microelectronics, energy storage devices, and chemical sensors. Overall, polyaniline (PAni) doped in acidic media has shown metal-like electronic conductivity, though exact physical and chemical properties are dependent on the polymer structure and dopant type. Difficulties arising from poor processability render production of doped PAni thin films particularly challenging. In this contribution, DC magnetron sputtering, a physical vapor deposition technique, is applied to the preparation of conductive thin films of PAni doped with hydrochloric acid (PAni-HCl) in an effort to circumvent issues associated with conventional thin film preparation methods. Samples manufactured by the sputtering method are analyzed along with samples prepared by conventional drop-casting. Physical characterization (atomic force microscopy, AFM) confirm the presence of PAni-HCl and show that films exhibit a reduced roughness and potentially pinhole-free coverage of the substrate. Spectroscopic evidence (UV-vis, FT-IR, and X-ray photoelectron spectroscopy (XPS)) suggests that structural changes and loss of conductivity, not uncommon during PAni processing, does occur during the preparation process. Finally, the applicability of sputtered films to gas-phase sensing of NH(3) was investigated with surface plasmon resonance (SPR) spectroscopy and compared to previous contributions. In summary, sputtered PAni-HCl films exhibit quantifiable, reversible behavior upon exposure to NH(3) with a calculated LOD (by method) approaching 0.4 ppm NH(3) in dry air.

  20. Structure, stability and electrochromic properties of polyaniline film covalently bonded to indium tin oxide substrate

    NASA Astrophysics Data System (ADS)

    Zhang, Wenzhi; Ju, Wenxing; Wu, Xinming; Wang, Yan; Wang, Qiguan; Zhou, Hongwei; Wang, Sumin; Hu, Chenglong

    2016-03-01

    Indium tin oxide (ITO) substrate was modified with 4-aminobenzylphosphonic acid (ABPA), and then the polyaniline (PANI) film covalently bonded to ITO substrate was prepared by the chemical oxidation polymerization. X-ray photoelectron spectroscopy (XPS), attenuated total reflection infrared (ATR-IR) spectroscopy, and atomic force microscopy (AFM) measurements demonstrated that chemical binding was formed between PANI and ABPA-modified ITO surface, and the maximum thickness of PANI layer is about 30 nm. The adhesive strength of PANI film on ITO substrate was tested by sonication. It was found that the film formed on the modified ITO exhibited a much better stability than that on bare one. Cyclic voltammetry (CV) and UV-vis spectroscopy measurements indicated that the oxidative potentials of PANI film on ABPA-modified ITO substrate were decreased and the film exhibited high electrochemical activities. Moreover, the optical contrast increased from 0.58 for PANI film (without ultrasound) to 1.06 for PANI film (after ultrasound for 60 min), which had an over 83% enhancement. The coloration time was 20.8 s, while the bleaching time was 19.5 s. The increase of electrochromic switching time was due to the lower ion diffusion coefficient of the large cation of (C4H9)4N+ under the positive and negative potentials as comparison with the small Li+ ion.

  1. Doping dependence of electrical and thermal conductivity of nanoscale polyaniline thin films

    NASA Astrophysics Data System (ADS)

    Jin, Jiezhu; Wang, Qing; Haque, M. A.

    2010-05-01

    We performed simultaneous characterization of electrical and thermal conductivity of 55 nm thick polyaniline (PANI) thin films doped with different levels of camphor sulfonic acids (CSAs). The effect of the doping level is more pronounced on electrical conductivity than on thermal conductivity of PANIs, thereby greatly affecting their ratio that determines the thermoelectric efficiency. At the 60% (the molar ratio of CSA to phenyl-N repeat unit of PANI) doping level, PANI exhibited the maximum electrical and thermal conductivity due to the formation of mostly delocalized structures. Whereas polarons are the charge carriers responsible for the electrical conduction, phonons are believed to play a dominant role in the heat conduction in nanoscale doped PANI thin films.

  2. The effect of material composition of 3-dimensional graphene oxide and self-doped polyaniline nanocomposites on DNA analytical sensitivity.

    PubMed

    Yang, Tao; Chen, Huaiyin; Yang, Ruirui; Wang, Xinxing; Nan, Fuxin; Jiao, Kui

    2015-09-01

    Until now, morphology effects of 2-dimensional or 3-dimensional graphene nanocomposites and the effect of material composition on the biosensors have been rarely reported. In this paper, the various nanocomposites based on graphene oxide and self-doped polyaniline nanofibres for studying the effect of morphology and material composition on DNA sensitivity were directly reported. The isolation and dispersion of graphene oxide were realized via intercalated self-doped polyaniline and ultrasonication, where the ultrasonication prompts the aggregates of graphite oxide to break up and self-doped polyaniline to diffuse into the stacked graphene oxide. Significant electrochemical enhancement has been observed due to the existence of self-doped polyaniline, which bridges the defects for electron transfer and, in the mean time, increases the basal spacing between graphene oxide sheets. Different morphologies can result in different ssDNA surface density, which can further influence the hybridization efficiency. Compared with 2-dimensional graphene oxide, self-doped polyaniline and other morphologies of nanocomposites, 3-dimensional graphene oxide-self-doped polyaniline nanowalls exhibited the highest surface density and hybridization efficiency. Furthermore, the fabricated biosensors presented the broad detection range with the low detection limit due to the specific surface area, a large number of electroactive species, and open accessible space supported by nanowalls.

  3. Elastomeric Conducting Polyaniline Formed Through Topological Control of Molecular Templates.

    PubMed

    Ding, Hangjun; Zhong, Mingjiang; Wu, Haosheng; Park, Sangwoo; Mohin, Jacob W; Klosterman, Luke; Yang, Zhou; Yang, Huai; Matyjaszewski, Krzysztof; Bettinger, Christopher John

    2016-06-28

    A strategy for creating elastomeric conducting polyaniline networks is described. Simultaneous elastomeric mechanical properties (E < 10 MPa) and electronic conductivities (σ > 10 S cm(-1)) are achieved via molecular templating of conjugated polymer networks. Diblock copolymers with star topologies processed into self-assembled elastomeric thin films reduce the percolation threshold of polyaniline synthesized via in situ polymerization. Block copolymer templates with star topologies produce elastomeric conjugated polymer composites with Young's moduli ranging from 4 to 12 MPa, maximum elongations up to 90 ± 10%, and electrical conductivities of 30 ± 10 S cm(-1). Templated polyaniline films exhibit Young's moduli up to 3 orders of magnitude smaller compared to bulk polyaniline films while preserving comparable bulk electronic conductivity. Flexible conducting polymers have prospective applications in devices for energy storage and conversion, consumer electronics, and bioelectronics. PMID:27175931

  4. Elastomeric Conducting Polyaniline Formed Through Topological Control of Molecular Templates.

    PubMed

    Ding, Hangjun; Zhong, Mingjiang; Wu, Haosheng; Park, Sangwoo; Mohin, Jacob W; Klosterman, Luke; Yang, Zhou; Yang, Huai; Matyjaszewski, Krzysztof; Bettinger, Christopher John

    2016-06-28

    A strategy for creating elastomeric conducting polyaniline networks is described. Simultaneous elastomeric mechanical properties (E < 10 MPa) and electronic conductivities (σ > 10 S cm(-1)) are achieved via molecular templating of conjugated polymer networks. Diblock copolymers with star topologies processed into self-assembled elastomeric thin films reduce the percolation threshold of polyaniline synthesized via in situ polymerization. Block copolymer templates with star topologies produce elastomeric conjugated polymer composites with Young's moduli ranging from 4 to 12 MPa, maximum elongations up to 90 ± 10%, and electrical conductivities of 30 ± 10 S cm(-1). Templated polyaniline films exhibit Young's moduli up to 3 orders of magnitude smaller compared to bulk polyaniline films while preserving comparable bulk electronic conductivity. Flexible conducting polymers have prospective applications in devices for energy storage and conversion, consumer electronics, and bioelectronics.

  5. Conductive polyurethane composites containing polyaniline-coated nano-silica.

    PubMed

    Liu, Bo-Tau; Syu, Jhan-Rong; Wang, De-Hua

    2013-03-01

    In this study, we used 1.2-Aminopropyltriethoxysilane (APTS) as a coupling agent to synthesize silica-polyaniline (PANI) core-shell nanoparticles. The core-shell nanoparticles and PANI oligomers were reacted with isocyanates to prepare the conductive polyurethane (PU)-PANI-silica nanocomposites. The core-shell-nanoparticle structure shows significant enhancement on electrical properties of the conductive nanocomposites even though only 0.0755-wt.% PANI was coated on the nano-silica. The surface resistance of the nanocomposite containing 5 wt.% PANI can reduce to ~10(8) Ω/sq, lowering two orders in contrast to the nanocomposite without the core-shell structure. In comparison with the neat PU, tensile strength and elongation of the nanocomposite containing silica-PANI core-shell nanoparticles can increase 3.1 and 3.8 times, respectively. We suspect that the extraordinary enhancement of electrical and mechanical properties may result from the fact that contact probability among PANI moieties and chemical bonding between particles and PU matrix increase due to the PANI coated on the surface of silica. PMID:23261334

  6. Reversible assembly and disassembly of amphiphilic assemblies by electropolymerized polyaniline films: effects rendered by varying the electropolymerization potential.

    PubMed

    Dutta, Kingshuk; Kundu, Patit P

    2013-06-27

    Polymer films that respond to a variety of stimuli are attractive candidates for location-specific guest molecule delivery. These systems release the guest molecules by polymer erosion; thus, these are mono-use systems. If a polymer film is used to disassemble amphiphilic assemblies containing sequestered guest molecules, the polymer erosion issue can be circumvented. However, charge-bearing vinyl polymers, upon interaction with amphiphilic assemblies, are known to adapt to a conformation that results in encapsulating guest molecules instead of releasing them. On the contrary, it has earlier been reported that a rigid, charge-bearing, and water-insoluble conjugated polyaniline film can effectively disassemble amphiphilic assemblies without causing much harm to the film. Herein, we demonstrate the effect rendered by varying the electropolymerization potential on the interaction efficiency between the positive charge-bearing polyaniline film and oppositely charged amphiphilic assemblies. In addition, it is also demonstrated that a film of oxidized polyaniline can be regenerated for repetitive disassembly of the amphiphilic assemblies, and concomitant guest molecule delivery.

  7. Magnetic behaviour of composites containing polyaniline-coated manganese-zinc ferrite

    NASA Astrophysics Data System (ADS)

    Kazantseva, N. E.; Vilčáková, J.; Křesálek, V.; Sáha, P.; Sapurina, I.; Stejskal, J.

    2004-02-01

    Polycrystalline manganese-zinc ferrite has been coated with polyaniline (PANI) and embedded into a polyurethane matrix. The complex permeability of the composites was studied in the frequency range 1 MHz-3 GHz. The conductivity of PANI coating was adjusted by controlled protonation with picric acid. Large shifts in the resonance frequency were observed as a function of varying PANI conductivity. The changes in the magnetic properties of the PANI-coated composite material are due to the change of the boundary conditions of the microwave field at the interface between the ferrite particle and polymer matrix. This effect is observed especially when the magnetic anisotropy of ferrite is low.

  8. Enhancement of photoelectric catalytic activity of TiO 2 film via Polyaniline hybridization

    NASA Astrophysics Data System (ADS)

    Wang, Yajun; Xu, Jing; Zong, Weizheng; Zhu, Yongfa

    2011-06-01

    A Polyaniline (PANI)/TiO 2 film coated on titanium foil was successfully prepared using the sol-gel method followed by a facile chemisorption. Compared with pristine TiO 2, the photocatalytic (PC) and photoelectrocatalytic (PEC) degradation rates of 2,4-dichlorophenol (2,4-DCP) with the PANI/TiO 2 film were enhanced by 22.2% and 57.5%, respectively. 2,4-DCP can be mineralized more effectively in the presence of PANI/TiO 2 film. The best PEC degradation efficiency of 2,4-DCP with the PANI/TiO 2 film was acquired at an external potential of 1.5 V with a layer of 1 nm thick PANI. The PANI/TiO 2 film was characterized by Raman spectra, Fourier transform infrared spectra (FT-IR), Auger electron spectroscopy (AES), and electrochemical analysis. These results indicated that there was a chemical interaction on the interface of PANI and TiO 2. This interaction may be of significance to promote the migration efficiency of carriers and induce a synergetic effect to enhance the PC and PEC activities.

  9. Exceptionally crystalline and conducting acid doped polyaniline films by level surface assisted solution casting approach

    NASA Astrophysics Data System (ADS)

    Puthirath, Anand B.; Methattel Raman, Shijeesh; Varma, Sreekanth J.; Jayalekshmi, S.

    2016-04-01

    Emeraldine salt form of polyaniline (PANI) was synthesized by chemical oxidative polymerisation method using ammonium persulfate as oxidant. Resultant emeraldine salt form of PANI was dedoped using ammonia solution and then re-doped with camphor sulphonic acid (CSA), naphthaline sulphonic acid (NSA), hydrochloric acid (HCl), and m-cresol. Thin films of these doped PANI samples were deposited on glass substrates using solution casting method with m-cresol as solvent. A level surface was employed to get homogeneous thin films of uniform thickness. Detailed X-ray diffraction studies have shown that the films are exceptionally crystalline. The crystalline peaks observed in the XRD spectra can be indexed to simple monoclinic structure. FTIR and Raman spectroscopy studies provide convincing explanation for the exceptional crystallinity observed in these polymer films. FESEM and AFM images give better details of surface morphology of doped PANI films. The DC electrical conductivity of the samples was measured using four point probe technique. It is seen that the samples also exhibit quite high DC electrical conductivity, about 287 S/cm for CSA doped PANI, 67 S/cm for NSA doped PANI 65 S/cm for HCl doped PANI, and just below 1 S/cm for m-cresol doped PANI. Effect of using the level surface for solution casting is studied and correlated with the observed crystallinity.

  10. Polyaniline-lead titanate composites for humidity sensing and EMI shielding applications

    NASA Astrophysics Data System (ADS)

    Manocha, Aarushi; Thomas, Jocelyn T.; Fathima, Hana; V, Suveetha; Faisal, Muhammad

    2015-06-01

    The present paper reports the humidity sensing and electromagnetic interference (EMI) shielding properties of synthesized polyaniline-lead titanate (PANi/PbTiO3) composites. The humidity sensing of the PAni/PbTiO3 composites was discussed in terms of change in direct current (DC) resistance with respect to percentage relative humidity (% RH) ranging from 20% to 90%. The EMI shielding properties of the composites were measured in the frequency range of 8-12 GHz (X-band), relevant for practical applications. The composites showed shielding effectiveness (SE) in the range -29 dB to -34 dB and the variations in the shielding effectiveness with the frequency was minimal at a fixed composition. The observed effective humidity sensing and EMI shielding properties highlights the prospects of multifunctional applications of these composites.

  11. Unprecedented Route to Ordered Polyaniline: Direct Synthesis of Highly Crystalline Fibrillar Films with Strong π-π Stacking Alignment.

    PubMed

    Gospodinova, Natalia; Ivanov, Dimitri A; Anokhin, Denis V; Mihai, Iulia; Vidal, Loïc; Brun, Sulyvan; Romanova, Julia; Tadjer, Alia

    2009-01-01

    Films of polyaniline (PANI) featuring about 80% crystallinity and characterised with strong π-π stacking alignment parallel to the film surface have been obtained directly after the original synthesis upon simple drying of the aqueous PANI suspension. A strong anisotropy in the growth of the nano-sized crystals produced during the synthesis results in the formation of micrometer-length fibrils perpendicular to the film surface in the course of water evaporation. The regular intercalation of water molecules between the PANI chains seems to be crucial for their ordering throughout the synthesis and film formation.

  12. Constructing magnetic polyaniline/metal hybrid nanostructures using polyaniline/Fe{sub 3}O{sub 4} composite hollow spheres as supports

    SciTech Connect

    Kong Lirong; Lu Xiaofeng; Jin, E; Jiang Shan; Bian Xiujie; Zhang Wanjin; Wang Ce

    2009-08-15

    Polyaniline (PANI)/Fe{sub 3}O{sub 4} composite hollow spheres have been successfully synthesized in one step using sulfonated polystyrene (PS) spheres as templates. The magnetic PANI hollow spheres were used as supports for noble metal nanoparticles (NPs) such as Au and Pd. The morphology, composition and magnetic properties of the resulting products were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, inductively coupled plasma (ICP) atomic spectra and vibrating sample magnetometer. The catalytic activity of magnetic PANI/Au composite shells on the oxidation of dopamine was investigated by cyclic voltammetry. The obtained results provide our product with a practical application for the detection of dopamine. On the other hand, the catalytic activity of magnetic PANI/Pd composite shells on the reduction of 4-nitroaniline was investigated by spectroscopic methods and compared with Pd/C catalyst which was already widely used in industrial production. - Graphical abstract: TEM image of PANI/Fe{sub 3}O{sub 4} hollow spheres which can be used as supports for a variety of catalysts such as noble metal nanoparticles. Based on the unique properties of polyaniline hollow spheres and Fe{sub 3}O{sub 4} NPs, we designed the synthesis of polyaniline/Fe{sub 3}O{sub 4} NPs composite hollow spheres as supports for catalysts such as noble metal NPs. As a result, the obtained composites exhibit enhanced catalytic activities and can be easily separated from reaction mixture by using an NdFeB permanent magnet.

  13. Spectroscopic study of the highly homogeneous polyaniline film formation on gold support

    NASA Astrophysics Data System (ADS)

    Morávková, Zuzana; Stejskal, Jaroslav; Trchová, Miroslava

    2016-01-01

    The oxidation of aniline with ammonium peroxydisulfate in the aqueous solution of acetic acid has two subsequent phases: the oxidation of the neutral aniline molecules at low acidity, which was followed by the oxidation of the anilinium cations after the acidity became higher. The final polyaniline film deposited on immersed surfaces is usually contaminated with semi-crystalline oligomers which precipitated during induction period from the reaction medium. To obtain a homogeneous film, which is important in the fabrication of many molecular electronic devices, we have studied the course of aniline oxidation in a view of new experimental evidence. In the unique series of experiments, the silicon or gold supports have been immersed in the reaction mixture at crucial stages of oxidation reaction, and the deposits at the end of the reaction were analyzed. The growth of a highly homogenous film on the gold-coated glass substrate immersed in the reaction mixture at the end of the polymerization period has been observed. The molecular structure of the products was monitored with UV-visible, infrared, and Raman spectroscopies. The possible mechanism of the film formation and the molecular mechanism of the surface interaction of chemisorbed aniline oligomers with gold support are proposed.

  14. Reversible immobilization of uricase on conductive polyaniline brushes grafted on polyacrylonitrile film.

    PubMed

    Bayramoğlu, Gülay; Altıntaş, Begüm; Arıca, M Yakup

    2011-02-01

    Polyacrylonitrile film (PAN) surfaces were modified with chemical polymerization of conductive polyaniline (PANI) in the presence of potassium dichromate as an oxidizing agent. The conductive films were used for immobilization of uricase. The surface resistance of the conductive film in this work was found to be 0.97 kΩ/cm. The maximum amount of immobilized enzyme on conductive film containing 2.4% PANI was about 216 μg/cm(2). The optimum pH for free and immobilized enzymes was observed at 7.0 and 7.5, respectively. The K (m) values for free and immobilized uricase were found to be 94 and 138 μM, respectively. V (max) values were calculated as 1.87 and 1.63 U/mg protein for the free and immobilized enzymes, respectively. Immobilized uricase exhibited ~68% of its original activity even after 2 months of storage at 4 °C while the free enzyme lost its initial activity within 4 weeks. PMID:20652599

  15. Schottky Diodes Based on Polyaniline/Multi-Walled Carbon Nanotube Composites

    NASA Astrophysics Data System (ADS)

    Hajibadali, A.; Nejad, M. Baghaei; Farzi, G.

    2015-08-01

    Polyaniline/multi-walled carbon nanotube composites (PANI/MWCNT), with various concentration of multi-walled carbon nanotube, were synthesized. Several Schottky diodes were fabricated, where PANI or PANI/MWCNT composites, aluminum, and gold were used as semiconductor, Schottky contact, and ohmic contact, respectively. Then current-voltage characteristics of the fabricated diodes were measured at room temperature and within the bias range of -5 to +5 V. The measurements were repeated three times for each sample to verify repeatability of experiment. The obtained results show that by increasing the MWCNT concentration, the current intensity increases. Furthermore, I-V characteristics of pure polyaniline Schottky diode follows the thermionic emission mechanism while the I-V characteristics of Schottky diodes based on PANI/MWCNT composites show two distinct power law regions. At lower voltages, the mechanism follows Ohm's Law, whereas at higher voltages, the mechanism is compatible with space charge limited conduction emission mechanism. The parameters of Schottky diodes were determined, and it was observed that critical voltage decreased when the concentration of MWCNT in the composite increased.

  16. Charge transport properties of water dispersible multiwall carbon nanotube-polyaniline composites

    NASA Astrophysics Data System (ADS)

    Sangeeth, C. S. Suchand; Jiménez, Pablo; Benito, Ana M.; Maser, Wolfgang K.; Menon, Reghu

    2010-05-01

    The transmission electron microscopy images of in situ prepared multiwall carbon nanotubes (MWNTs) and polyaniline (PANI) composites show that nanotubes are well dispersed in aqueous medium, and the nanofibers of PANI facilitate intertube transport. Although low temperature transport indicates variable range hopping (VRH) mechanism, the dc and ac conductivity become temperature independent as the MWNT content increases. The onset frequency for the increase in conductivity is observed to be strongly dependent on the MWNT weight percent, and the ac conductivity can be scaled onto a master curve. The negative magnetoresistance is attributed to the forward interference scattering mechanism in VRH transport.

  17. Room temperature positive magnetoresistance via charge trapping in polyaniline-iron oxide nanoparticle composites

    NASA Astrophysics Data System (ADS)

    Lin, Aigu L.; Wu, Tom; Chen, Wei; Wee, Andrew T. S.

    2013-07-01

    We demonstrate a polyaniline-iron oxide nanoparticle (PANI-NP) organic hybrid composite device with room temperature positive magnetoresistance of 85.7%. Temperature dependent resistivity measurements attribute this observation to the decrease in localization length of the charge carriers in the presence of an external magnetic field which result in them being trapped within the device between the insulating PANI layer, hence allowing the device to maintain its resistive state even when the power is switched off, thus exhibiting a memory effect.

  18. Polymer film composite transducer

    DOEpatents

    Owen, Thomas E.

    2005-09-20

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

  19. Synthesis of SBA-15/polyaniline mesoporous composite for removal of resorcinol from aqueous solution

    NASA Astrophysics Data System (ADS)

    Li, Qiang; Yu, Hui; Song, Jie; Pan, Xianhui; Liu, Jing; Wang, Yi; Tang, Linhong

    2014-01-01

    Polyaniline (PA) modified mesoporous SBA-15 composite (SBA-15/PA) was synthesized by respectively using aniline and ammonium persulfate as modifying agent and oxidant at 0 °C as a novel adsorbent for efficiently removing the resorcinol pollutant from aqueous solution. This material was investigated under the help of various characterization approaches, which suggests that it exhibits ordered two-dimensionally (2D) hexagonal mesostructure, high specific surface area (219.6 m2/g) and narrow pore size distribution centered at 8.8 nm. Polyaniline have been successfully modified on the pore wall of SBA-15. The adsorption experiments demonstrated that the SBA-15/PA composite can be used as an excellent adsorbent for removing resorcinol. Its uptake capacity can reach up to 128 mg/g in 250 mg L-1 of resorcinol solution. In addition, batch experiments were also conducted for analyzing the effects of adsorption conditions on the uptake capacity of the mesoporous composite, including pH value, adsorption temperature, and solution salinity. Moreover, kinetics of the adsorption process was studied by investigating the concentration changes of resorcinol solution with adsorption times. The driving forces for the adsorption process derive from the hydrogen-bond, π-π stacking, and acid-base interactions between the adsorbent and adsorbate. The high specific surface area and ordered mesochannels are also advantageous for the adsorption process.

  20. Polyaniline nanofiber/large mesoporous carbon composites as electrode materials for supercapacitors

    NASA Astrophysics Data System (ADS)

    Liu, Huan; Xu, Bin; Jia, Mengqiu; Zhang, Mei; Cao, Bin; Zhao, Xiaonan; Wang, Yu

    2015-03-01

    A composite of polyaniline nanofiber/large mesoporous carbon (PANI-F/LMC) hybrid was prepared by an in situ chemical oxidative polymerization of aniline monomer with nano-CaCO3 templated LMC as host matrix for supercapacitors. The morphology, composition and electronic structure of the composites (PANI-F/LMC) together with pure PANI nanofibers and the LMC were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), FT-IR, X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). It is found that the PANI nanofibers were incorporated into the large mesochannels of LMC with interpenetrating framework formed. Such unique structure endows the PANI-F/LMC composite with a high capacitance of 473 F g-1 at a current load of 0.1 A g-1 with good rate performance and cycling stability, suggesting its potential application in the electrode material for supercapacitors.

  1. Reversible immobilization of glucose oxidase on polyaniline grafted polyacrylonitrile conductive composite membrane.

    PubMed

    Bayramoğlu, Gülay; Metin, Ayşegül U; Altintas, Begum; Arica, M Yakup

    2010-09-01

    Polyacrylonitrile membrane surfaces were modified with chemical polymerization of conductive polyaniline. The effect of aniline concentration on the grafting efficiency was investigated. As the amount of grafted PANI increased on the PAN membrane, the electrical resistance of composite membrane decreased. Composite (PAN/PANI)-1-5 membrane were used for reversible immobilization of GOD. The immobilization efficiency and the activity of the immobilized GOD were increased with increasing PANI contents of the composite membrane. The maximum amount of immobilized enzyme into composite PAN/PANI-5 membrane containing 2.1% PANI was about 251 microg/cm(2). Immobilized GOD exhibited 66% of its original activity even after two months of storage at 4 degrees C while the free enzyme lost its initial activity after three weeks. PMID:20444598

  2. Oriented ZnO nanorods grown on a porous polyaniline film as a novel coating for solid-phase microextraction.

    PubMed

    Zeng, Jingbin; Zhao, Cuiying; Chong, Fayun; Cao, Yingying; Subhan, Fazle; Wang, Qianru; Yu, Jianfeng; Zhang, Maosheng; Luo, Liwen; Ren, Wei; Chen, Xi; Yan, Zifeng

    2013-12-01

    In this work, oriented ZnO nanorods (ZNRs) were in situ hydrothermally grown on a porous polyaniline (PANI) film to function as a solid-phase microextraction (SPME) coating. Scanning electron microscopy (SEM) study revealed that the majority of oriented ZNRs grew from pores of PANI matrix, which protected the ZNRs from easily peeling off during operation. Furthermore, in this process, a thin layer of PANI was found to cover the ZNRs, which can enlarge the effective surface area of the composite coating. This ZNRs/PANI composite coating combined the merits of both ZNRs and PANI and, thus, has several advantages over that of sole PANI film and ZNRs coating such as improved extraction efficiency for benzene homologues, enhanced mechanical stability and longer service life (over 150 cycles of SPME-GC operation). Coupled with gas chromatography-flame ionization detector (GC-FID), the optimized SPME-GC-FID method was used for the analysis of six benzene homologues in water samples. The calibration curves were linear from 1 to 1000μgL(-1) for each analyte, and the limits of detection were between 0.001 and 0.024μgL(-1). Single fiber repeatability and fiber-to-fiber reproducibility were in the range of 1.3-6.8% and 5.3-11.2%, respectively. The spiked recoveries at 100 and 5μgL(-1) for three environmental water samples were in the range of 79.8-115.4% and 73.7-117.4%, respectively.

  3. Thin-film microelectric arrays for amperometric enzyme biosensors with electrochemically synthesized glucose oxidase-polyaniline membrane

    NASA Astrophysics Data System (ADS)

    Dzyadevich, Sergei V.; Rossokhaty, Victor K.; Shram, Nataly; Shul'ga, Alexander A.; Soldatkin, Alexey P.; Strikha, Vitaly I.

    1994-10-01

    An amperometric glucose biosensor was fabricated by the electrochemical polymerization of aniline onto a gold electrodes in presence of glucose oxidase in phosphate buffer solution, pH 7.0. Aniline is easily polymerized forming a thin film, which adheres tightly on the electrodes surface. During the electropolymerization process the enzyme was entrapped into the polyaniline film being able to catalyze the hydrolysis of glucose. The experiments were performed to determine the optimal condition for polyaniline-glucose oxidase film preparation. Glucose can be determined by the biosensor in the concentration range 10-4 M to 2 X 10-2 M. The linearity of the biosensor response was observed from 2 X 10-4 M to 6 X 10-3 M glucose, which demonstrated that the internal diffusion of substrates and products of reaction through the polyaniline layer to the electrodes surface was the main limiting factor controlling the response value. The method of electropolymerization was found to have several advantage in comparison with other approaches especially for further mass manufacturing of the biosensors.

  4. Temperature characterization of dielectric permittivity and AC conductivity of nano copper oxide-doped polyaniline composite

    NASA Astrophysics Data System (ADS)

    Shubha, L. N.; Madhusudana Rao, P.

    2016-06-01

    The polyaniline/copper oxide (PANI/CuO) nanocomposite was prepared by mixing solutions of polyaniline and copper oxide nanoparticles in dimethyl sulfoxide (DMSO). The synthesized polymer nanocomposites were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM) and UV-visible spectroscopy. The characteristic peaks in XRD and UV-visible spectra confirmed the presence of CuO in the polymer structure. SEM images indicated morphological changes in the composite matrix as compared to the pristine PANI. The DC conductivity measurements were performed using two-probe method for various temperatures. AC conductivity and dielectric response of the composites were investigated in the frequency range of 102-106Hz using LCR meter. Dielectric permittivity ɛ‧(w) and dielectric loss factor ɛ‧‧(w) were investigated. It was observed that ɛ‧(w) and ɛ‧‧(w) decrease with increase in frequency at all temperatures. At a particular frequency it is observed that both ɛ‧(w) and ɛ‧‧(w) increase with increase in temperature. It was also observed that AC conductivity increased with increase in frequency and temperature.

  5. Graphene/polyaniline composite sponge of three-dimensional porous network structure as supercapacitor electrode

    NASA Astrophysics Data System (ADS)

    Jiu-Xing, Jiang; Xu-Zhi, Zhang; Zhen-Hua, Wang; Jian-Jun, Xu

    2016-04-01

    As a supercapacitor electrode, the graphene/polyaniline (PANI) composite sponge with a three-dimensional (3D) porous network structure is synthesized by a simple three-step method. The three steps include an in situ polymerization, freeze-drying and reduction by hydrazine vapor. The prepared sponge has a large specific surface area and porous network structure, so it is in favor of spreading the electrolyte ion and increasing the charge transfer efficiency of the system. The process of preparation is simple, easy to operate and low cost. The composite sponge shows better electrochemical performance than the pure individual graphene sponge while PANI cannot keep the shape of a sponge. Such a composite sponge exhibits specific capacitances of 487 F·g‑1 at 2 mV/s compared to pristine PANI of 397 F·g‑1. Project supported by the Natural Science Foundation from Harbin University of Science and Technology and Harbin Institute of Technology.

  6. Graphene/polyaniline composite sponge of three-dimensional porous network structure as supercapacitor electrode

    NASA Astrophysics Data System (ADS)

    Jiu-Xing, Jiang; Xu-Zhi, Zhang; Zhen-Hua, Wang; Jian-Jun, Xu

    2016-04-01

    As a supercapacitor electrode, the graphene/polyaniline (PANI) composite sponge with a three-dimensional (3D) porous network structure is synthesized by a simple three-step method. The three steps include an in situ polymerization, freeze-drying and reduction by hydrazine vapor. The prepared sponge has a large specific surface area and porous network structure, so it is in favor of spreading the electrolyte ion and increasing the charge transfer efficiency of the system. The process of preparation is simple, easy to operate and low cost. The composite sponge shows better electrochemical performance than the pure individual graphene sponge while PANI cannot keep the shape of a sponge. Such a composite sponge exhibits specific capacitances of 487 F·g-1 at 2 mV/s compared to pristine PANI of 397 F·g-1. Project supported by the Natural Science Foundation from Harbin University of Science and Technology and Harbin Institute of Technology.

  7. Polyaniline-copper oxide composite: A high performance shield against electromagnetic pollution

    NASA Astrophysics Data System (ADS)

    Rahul, Duvvuri Surya; Pais, Tyson P. M.; Sharath, N.; Ali, Syed Amjad; Faisal, Muhammad

    2015-06-01

    This work reports the electromagnetic interference (EMI) shielding properties of polyaniline-copper oxide PAni/CuO composites prepared by in-situ emulsion polymerization. The shielding measurements have been carried out in the microwave frequency range of 8 to 12 GHz (X-band). The composites showed total EMI shielding effectiveness (SE) of -32 to -37.3 dB (> 99.99 % attenuation) with higher dielectric loss (ɛ″) in the range of 142 to 165, indicating their potential as high performance shield throughout the X-band. The results indicate that the electromagnetic properties of the composites depend on the content of CuO in PAni matrix.

  8. (Metal-Organic Framework)-Polyaniline sandwich structure composites as novel hybrid electrode materials for high-performance supercapacitor

    NASA Astrophysics Data System (ADS)

    Guo, ShuaiNan; Zhu, Yong; Yan, YunYun; Min, YuLin; Fan, JinChen; Xu, QunJie; Yun, Hong

    2016-06-01

    Carbonized Zn-(Metal-Organic Framework)MOF- polyaniline composites for high performance of supercapacitor have been developed from zinc acetate, 8-Hydroxyquinoline, and aniline via a simple process. The as-synthesized product has been characterized by X-ray powder diffraction (XRD), Scanning electron microscopy(SEM), Fourier transform infrared spectra (FT-IR), Transmission electron microscope (TEM). The electrochemical properties of carbonized Zn-MOF/polyaniline electrode were investigated by current charge-discharge and cyclic voltammetry. The specific capacitance of MOF/PANI has been approach to be as high as 477 F g-1 at a current density of 1 A g-1.

  9. Facile route to covalently-jointed graphene/polyaniline composite and it's enhanced electrochemical performances for supercapacitors

    NASA Astrophysics Data System (ADS)

    Qiu, Hanxun; Han, Xuebin; Qiu, Feilong; Yang, Junhe

    2016-07-01

    A polyaniline/graphene composite with covalently-bond is synthesized by a novel approach. In this way, graphene oxide is functionalized firstly by introducing amine groups onto the surface with the reduction of graphene oxide in the process and then served as the anchor sites for the growth of polyaniline (PANI) via in-situ polymerization. The composite material is characterized by electron microscopy, the resonant Raman spectra, X-ray diffraction, transform infrared spectroscopy and X-ray photoelectron spectroscopy. The electrochemical properties of the composite are measured by cyclic voltammetry, electrochemical impedance spectroscopy and galvanostatic charging/discharging. With the functionalization process, the graphene/polyaniline composite electrode exhibits remarkably enhanced electrochemical performance with specific capacitance of 489 F g-1 at 0.5 A g-1, which is superior to those of its individual components. The outstanding electrochemical performance of the hybrid can be attributed to its covalently synergistic effect between graphene and polyaniline, suggesting promising potentials for supercapacitors.

  10. Role of polyaniline on the photocatalytic degradation and stability performance of the polyaniline/silver/silver phosphate composite under visible light.

    PubMed

    Bu, Yuyu; Chen, Zhuoyuan

    2014-10-22

    Polyaniline/silver/silver phosphate (PANI/Ag/Ag3PO4) composite was prepared by in situ depositing silver phosphate (Ag3PO4) nanoparticles on the surface of polyaniline (PANI). The best photocatalytic Rhodamine B degradation performance is obtained by the 20 wt % PANI/Ag/Ag3PO4 composite, which is approximately 4 times higher than that of pure Ag3PO4. Meanwhile, the photocatalytic stability of Ag3PO4 is significantly improved by introducing PANI into the PANI/Ag/Ag3PO4 composite. The dramatic promotion of the photocatalytic degradation performance and the photocatalytic stability can be attributed to the formation of a heterojunction electric field between PANI and Ag3PO4, which is approximately 90 mV and points from Ag3PO4 to PANI. The existence of this electric field can dramatically enhance the separation efficiency of the photogenerated electron-hole pairs, accelerate the transfer of photogenerated holes from Ag3PO4 to PANI and therefore inhibit the self-oxidation of Ag3PO4.

  11. Structural, thermal and electrical characterizations of multiwalled carbon nanotubes and polyaniline composite

    NASA Astrophysics Data System (ADS)

    Singh, Kamal; Garg, Leena; Singh, Jaspal; Kumar, Sanjeev; Sharma, Amit L.

    2016-05-01

    The undoped and doped composite of MWNTs (Multiwalled Carbon Nanotubes) with PANI (/Polyaniline) was prepared by chemical oxidative polymerization. The MWNTs/PANI composites have been characterized by using various techniques like Thermogravometric Analysis (TGA), Fourier transform infrared (FT-IR) spectrometer and Field emission scanning electron microscope (FE-SEM) and conductivity measurement by using two probe method. TGA results has shown that thermal stability followed the pattern undoped MWNTs/PANI composite < doped MWNTs/PANI composite. FE-SEM micrographs demonstrated the morphological changes on the surface of MWNTs as a result of composite formation. Fourier transformed infrared (FT-IR) spectra ascertained the formation of the composite. Study of electrical characteristics demonstrated that the doped MWNTs/PANI composite (1.2 × 101 Scm-1) have better conductivity than the undoped MWNTs/PANI composite (10-4 Scm-1). These CNTs based polymeric composites are of great importance in developing new nano-scale devices for future chemical, mechanical and electronic applications.

  12. Correlation of Structural Differences between Nafion/Polyaniline and Nafion/Polypyrrole Composite Membranes and Observed Transport Properties

    SciTech Connect

    Schwenzer, Birgit; Kim, Soowhan; Vijayakumar, M.; Yang, Zhenguo; Liu, Jun

    2011-04-15

    Polyaniline/Nafion and polypyrrole/Nafion composite membranes, prepared by chemical polymerization, are studied by infrared and nuclear magnetic resonance spectroscopy, and scanning electron microscopy. Differences in vanadium ion diffusion through the membranes and in the membranes’ area specific resistance are linked to analytical observations that polyaniline and polypyrrole interact differently with Nafion. Polypyrrole, a weakly basic polymer, binds less strongly to the sulfonic acid groups of the Nafion membrane, and thus the hydrophobic polymer aggregates in the center of the Nafion channel rather than on the hydrophilic side chains of Nafion that contain sulfonic acid groups. This results in a drastically elevated membrane resistance and an only slightly decreased vanadium ion permeation compared to a Nafion membrane. Polyaniline on the other hand is a strongly basic polymer, which forms along the sidewalls of the Nafion pores and on the membrane surface, binding tightly to the sulfonic acid groups of Nafion. This leads to a more effective reduction in vanadium ion transport across the polyaniline/Nafion membranes and the increase in membrane resistance is less severe. The performance of selected polypyrrole/Nafion composite membranes is tested in a static vanadium redox cell. Increased coulombic efficiency, compared to a cell employing Nafion, further confirms the reduced vanadium ion transport through the composite membranes.

  13. Odd-Even Pattern Observed in Polyaniline/(Au0 – Au8) Composites

    SciTech Connect

    Jonke, Alex P.; Josowicz, Mira A.; Janata, Jiri

    2012-01-12

    Theoretically predicted effect of odd-even pattern of electron pairing on behavior of gold clusters in polyaniline/AuN (N = 0 to 8) has been confirmed experimentally. In these composites the atomic Au clusters with even number of atoms exhibit higher catalytic activity for electrochemical oxidation of n-propanol in 1 M NaOH than the odd-number atoms clusters. Also, infrared spectroscopy shows that even numbered PANI/AuN composites affect the N-H stretching vibration more strongly than the corresponding odd numbered ones. This behavior matches the theoretically predicted variations of HOMO-LUMO gap energy and the stability of the atomic Au clusters. It also agrees with the earlier experimental work in which the UPS spectra of isolated, mass-selected Au clusters have been reported.

  14. Modification of inner surface of photonic crystal fibers with self-assembled polyaniline films

    NASA Astrophysics Data System (ADS)

    Pidenko, Sergei A.; Pidenko, Pavel S.; Bondarenko, Sergei D.; Shuvalov, Andrei A.; Burmistrova, Natalia A.; Goryacheva, Irina Y.

    2016-04-01

    Photonic crystal fibers (PCFs) with a hollow core are one of the most promising solid support of fiber-optic sensors. The main advantages of PCF as sensor elements in clinical analysis are minimization of optical interactions from the sample and the ability to analyze small volume of samples. At the same time, low sorption capacity of glass which is the basic material for the fabrication of the PCF, limits their use in the development of biosensors. Modification of the inner surface of the PCF can be the solution of the problem. In this work the synthesis of self-assembled films of polyaniline (PANI) on the inner surface of the PCFs was carried out. The modified PCFs were studied by spectroscopy and electron microscopy. It was found that the covering of the inner surface of the PCFs with PANI leads to a shift of the local maximums of the transmission spectrum PCFs up to 25 nm. These makes possible to design the method of varying of photonic bandgaps location.

  15. Electrochemical performance evaluation of polyaniline/lithium manganese nickel oxide composites synthesized using surfactant agents

    NASA Astrophysics Data System (ADS)

    Neves, Silmara; Canobre, Sheila C.; Oliveira, Rafael S.; Fonseca, Carla Polo

    The effect of adding a non-ionic surfactant to disperse oxide particles on the electrochemical performance of PAni/LiMnNiO 4 composites is evaluated by using cyclic voltammetry (CV), impedance measurements and constant-current charge/discharge cycling techniques. Three surfactants based on ethoxylated (EO) and propoxylated (PO) lauryl alcohols (3EO/6PO, L306; 4EO/5PO, L405; and 6EO/3PO, L603) were investigated. For comparative purposes, the oxide and polyaniline were prepared by sol-gel and chemical methods and were also investigated for their physical and electrochemical performances. By galvanostatic charge-discharge tests, the PAni/LiMnNiO 4 L306 composite showed a better electrochemical performance than each single component and other composites (PAni/LiMnNiO 4 L405 and PAni/LiMnNiO 4 L603). The electrical conductivity of this composite reached 21.7 S cm -1, and an initial discharge capacity of 198 mAh g -1 was obtained. After 21 cycles, the retention capacity was 91%. These results indicate a synergistic effect among the materials in the composite. Analytical techniques, such as scanning electron microscopy (SEM), X-ray diffraction spectroscopy (XRD) and inductively coupled plasma-atomic emission spectrometry (ICP-AES) were also used to characterize the composite materials.

  16. Polyaniline modified graphene and carbon nanotube composite electrode for asymmetric supercapacitors of high energy density

    NASA Astrophysics Data System (ADS)

    Cheng, Qian; Tang, Jie; Shinya, Norio; Qin, Lu-Chang

    2013-11-01

    Graphene and single-walled carbon nanotube (CNT) composites are explored as the electrodes for supercapacitors by coating polyaniline (PANI) nano-cones onto the graphene/CNT composite to obtain graphene/CNT-PANI composite electrode. The graphene/CNT-PANI electrode is assembled with a graphene/CNT electrode into an asymmetric pseudocapacitor and a highest energy density of 188 Wh kg-1 and maximum power density of 200 kW kg-1 are achieved. The structure and morphology of the graphene/CNT composite and the PANI nano-cone coatings are characterized by both scanning electron microscopy and transmission electron microscopy. The excellent performance of the assembled supercapacitors is also discussed and it is attributed to (i) effective utilization of the large surface area of the three-dimensional network structure of graphene-based composite, (ii) the presence of CNT in the composite preventing graphene from re-stacking, and (ii) uniform and vertically aligned PANI coating on graphene offering increased electrical conductivity.

  17. Preparation, magnetic and electromagnetic properties of polyaniline/strontium ferrite/multiwalled carbon nanotubes composite

    NASA Astrophysics Data System (ADS)

    Li, Yuqing; Huang, Ying; Qi, Shuhua; Niu, Lei; Zhang, Yinling; Wu, Yanfei

    2012-02-01

    Strontium ferrite particles were firstly prepared by sol-gel method and self-propagating synthesis, and then the polyaniline/strontium ferrite/multiwalled carbon nanotubes composites were synthesized through in situ polymerization approach. Structure, morphology and properties of the composite were characterized by various instruments. XRD analysis shows that the output of PANI increases with the increase of the content of MWCNTs, due to the large surface area of MWCNTs. Because of the coating of PANI, the outer diameter of MWCNTs increases from 10 nm to 20-40 nm. The electrical conductivity of the composites increases with the amount increase of MWCNTs and reaches 7.2196 S/cm in the presence of 2 g MWCNTs. The coercive force of the composites prepared with 2 g MWCNTs is 7457.17 Oe, which is much bigger than that of SrFe12O19 particles 6145.6 Oe, however, both the saturation magnetization and the remanent magnetization of the composite become much smaller than those of SrFe12O19 particles. The electromagnetic properties of the composite are excellent in the frequency range of 2-18 GHz, which mainly depend on the dielectric loss in the range of 2-9 GHz, and mainly on the magnetic loss in the range of 9-18 GHz.

  18. Preparation and electrochemical characterization of polyaniline/activated carbon composites as an electrode material for supercapacitors.

    PubMed

    Oh, Misoon; Kim, Seok

    2012-01-01

    Polyaniline (PANI)/activated carbon (AC) composites were prepared by a chemical oxidation polymerization. To find an optimum ratio between PANI and AC which shows superior electrochemical properties, the preparation was carried out in changing the amount of added aniline monomers. The morphology of prepared composites was investigated by scanning electron microscopy (SEM) and transmission electron microscope (TEM). The structural and thermal properties were investigated by Fourier transform infrared spectra (FT-IR) and thermal gravimetric analysis (TGA), respectively. The electrochemical properties were characterized by cyclic voltammetry (CV). Composites showed a summation of capacitances that consisted of two origins. One is double-layer capacitance by ACs and the other is faradic capacitance by redox reaction of PANI. Fiber-like PANIs are coated on the surface of ACs and they contribute to the large surface for redox reaction. The vacancy among fibers provided the better diffusion and accessibility of ion. High capacitances of composites were originated from the network structure having vacancy made by PANI fibers. It was found that the composite prepared with 5 ml of aniline monomer and 0.25 g of AC showed the highest capacitance. Capacitance of 771 F/g was obtained at a scan rate of 5 mV/s.

  19. Low temperature synthesis of polyaniline-crystalline TiO2-halloysite composite nanotubes with enhanced visible light photocatalytic activity.

    PubMed

    Li, Cuiping; Wang, Jie; Guo, Hong; Ding, Shujiang

    2015-11-15

    A series of one-dimensional polyaniline-crystalline TiO2-halloysite composite nanotubes with different mass ratio of polyaniline to TiO2 are facilely prepared by employing the low-temperature synthesis of crystalline TiO2 on halloysite nanotubes. The halloysite nanotubes can adsorb TiO2/polyaniline precursors and induce TiO2 nanocrystals/polyaniline to grow on the support in situ simultaneously. By simply adjusting the acidity of reaction system, PANI-crystalline TiO2-HA composite nanotubes composed of anatase, a mixed phase TiO2 and different PANI redox state are obtained. The XRD and UV-vis results show that the surface polyaniline sensitization has no effect on the crystalline structure of halloysite and TiO2 and the light response of TiO2 is extended to visible-light regions. Photocatalysis test results reveal the photocatalytic activity will be affected by the pH value and the volume ratio of ANI to TTIP. The highest photocatalytic activity is achieved with the composite photocatalysts prepared at pH 0.5 and 1% volume ratio of ANI and TTIP owing to the sensitizing effect of polyaniline and the charge transfer from the photoexcited PANI sensitizer to TiO2. Moreover, the PANI-TiO2-HA composite nanotubes synthesized by one-step at pH 0.5 with 1% volume ratio of ANI to TTIP exhibit higher visible light photocatalytic activity than those synthesized by the two-step. Heterogeneous PANI-TiO2-HA composite nanotubes prepared at pH 0.5 exhibit a higher degradation activity than that prepared at pH 1.5. The redoped experiment proves that the PANI redox state plays the main contribution to the enhanced visible light catalytic degradation efficiency of PANI-TiO2-HA prepared at pH 0.5. Furthermore, the heterogeneous PANI-crystalline TiO2-HA nanotubes have good photocatalytic stability and can be reused four times with only gradual loss of activity under visible light irradiation. PMID:26197106

  20. Low temperature synthesis of polyaniline-crystalline TiO2-halloysite composite nanotubes with enhanced visible light photocatalytic activity.

    PubMed

    Li, Cuiping; Wang, Jie; Guo, Hong; Ding, Shujiang

    2015-11-15

    A series of one-dimensional polyaniline-crystalline TiO2-halloysite composite nanotubes with different mass ratio of polyaniline to TiO2 are facilely prepared by employing the low-temperature synthesis of crystalline TiO2 on halloysite nanotubes. The halloysite nanotubes can adsorb TiO2/polyaniline precursors and induce TiO2 nanocrystals/polyaniline to grow on the support in situ simultaneously. By simply adjusting the acidity of reaction system, PANI-crystalline TiO2-HA composite nanotubes composed of anatase, a mixed phase TiO2 and different PANI redox state are obtained. The XRD and UV-vis results show that the surface polyaniline sensitization has no effect on the crystalline structure of halloysite and TiO2 and the light response of TiO2 is extended to visible-light regions. Photocatalysis test results reveal the photocatalytic activity will be affected by the pH value and the volume ratio of ANI to TTIP. The highest photocatalytic activity is achieved with the composite photocatalysts prepared at pH 0.5 and 1% volume ratio of ANI and TTIP owing to the sensitizing effect of polyaniline and the charge transfer from the photoexcited PANI sensitizer to TiO2. Moreover, the PANI-TiO2-HA composite nanotubes synthesized by one-step at pH 0.5 with 1% volume ratio of ANI to TTIP exhibit higher visible light photocatalytic activity than those synthesized by the two-step. Heterogeneous PANI-TiO2-HA composite nanotubes prepared at pH 0.5 exhibit a higher degradation activity than that prepared at pH 1.5. The redoped experiment proves that the PANI redox state plays the main contribution to the enhanced visible light catalytic degradation efficiency of PANI-TiO2-HA prepared at pH 0.5. Furthermore, the heterogeneous PANI-crystalline TiO2-HA nanotubes have good photocatalytic stability and can be reused four times with only gradual loss of activity under visible light irradiation.

  1. Grafting of poly(ethylene oxide) to the surface of polyaniline films through a chlorosulfonation method and the biocompatibility of the modified films.

    PubMed

    Li, Z F; Ruckenstein, E

    2004-01-01

    Poly(ethylene oxide) (PEO) could be grafted on the surface of polyaniline (PANI) films by chlorosulfonating the films with chlorosulfonic acid followed by reacting the modified films with PEO in a pyridine solution. The modified PANI films were examined by X-ray photoelectron spectroscopy and water droplet contact angles. The surface of the PEO grafted to hydrophobic PANI films became hydrophilic and the amounts of bovine serum albumin and human blood plasma platelet adsorbed onto it were decreased by more than 80%. For comparison purposes, and because the water wetting angle can be used as a measure of biocompatibility, wetting angle experiments have been also carried out for Pluronic triblock copolymer grafted to PANI and PEO or Pluronic molecules entrapped on the surfaces of PANI films. PANI was selected as substrate because one can easily change its surface properties by PEO grafting and because being conductive can be used as a sensor.

  2. Nanostructured polyaniline rice husk composite as adsorption materials synthesized by different methods

    NASA Astrophysics Data System (ADS)

    Tot Pham, Thi; Thanh Thuy Mai, Thi; Quy Bui, Minh; Mai, Thi Xuan; Yen Tran, Hai; Binh Phan, Thi

    2014-03-01

    Composites based on polyaniline (PANi) and rice husk (RH) were prepared by two methods: the first one was chemical method by combining RH contained in acid medium and aniline using ammonium persulfate as an oxidation agent and the second one was that of soaking RH into PANi solution. The presence of PANi combined with RH to form nanocomposite was clearly demonstrated by infrared (IR) spectra as well as by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) images. Lead(II) and cadmium(II) ion concentrations in solution before and after adsorption process on those composites were analysed by atomic adsorption spectroscopy. Of the above preparation methods, the soaking one provided a composite onto which the maximum adsorption capacity was higher for lead(II) ion (200 mg g-1), but lower for cadmium(II) ion (106.383 mg g-1) in comparison with the chemical one. However, their adsorption process occurring on both composites also fitted well into the Langmuir isotherm model.

  3. Polyaniline/reduced graphene oxide/Fe3O4 nano-composite for aqueous Hg(II) removal.

    PubMed

    Li, Renjie; Liu, Lifen; Yang, Fenglin

    2015-01-01

    To ease the adsorbent recovery and to increase the adsorption capacity of polyaniline (PANI), aniline was polymerized in the presence of a solvothermally prepared nano-composite of reduced graphene oxide and Fe3O4 (RGO/Fe3O4). The polyaniline was formed along the RGO/Fe3O4 composite in transmission electron microscope (TEM). The thus formed PANI/RGO/Fe3O4 adsorbent was tested and applied in removing Hg(II) in aqueous solution. The initial adsorption rate as well as the adsorption capacity increases with the incorporation of RGO/Fe3O4. The magnetic separation of PANI/RGO/Fe3O4 was easy, and its regeneration can be carried out at the optimal pH of 2. Test results proved the competence of the prepared adsorbent in pollution remediation applications for safer water quality and environmental protection. PMID:26606101

  4. TiO{sub 2}/PANI And MWNT/PANI Composites Thin Films For Hydrogen Gas Sensing

    SciTech Connect

    Srivastava, Subodh; Kumar, Sumit; Agrawal, Shweta; Saxena, Arpita; Choudhary, B. L.; Mathur, Shubhra; Singh, M.; Vijay, Y. K.

    2010-12-01

    The MWNT and TiO{sub 2} doped Polyaniline (PANI) composites were synthesized by In-situ chemical oxidative polymerization method at low temperature. The MWNT/PANI and TiO{sub 2}/PANI composite thin films were prepared using spin coating method onto finger type interdigited electrodes to develop the chemiresistor type gas sensor for hydrogen gas sensing application. It was observed that the MWNT and TiO{sub 2} doped PANI composite thin films show a higher response in comparision to neat PANI. The structural and morphological properties of these composite films were characterized by X-Ray differaction (XRD) pattern and sccaning electrone microscopy (SEM) respectively.

  5. High-performance supercapacitors using graphene/polyaniline composites deposited on kitchen sponge

    NASA Astrophysics Data System (ADS)

    Moussa, Mahmoud; El-Kady, Maher F.; Wang, Hao; Michimore, Andrew; Zhou, Qinqin; Xu, Jian; Majeswki, Peter; Ma, Jun

    2015-02-01

    We in this study used a commercial grade kitchen sponge as the scaffold where both graphene platelets (GnPs) and polyaniline (PANi) nanorods were deposited. The high electrical conductivity of GnPs (1460 S cm-1) enhances the pseudo-capacitive performance of PANi grown vertically on the GnPs basal planes; the interconnected pores of the sponge provide sufficient inner surface between the GnPs/PANi composite and the electrolyte, which thus facilitates ion diffusion during charge and discharge processes. When the composite electrode was used to build a supercapacitor with two-electrode configuration, it exhibited a specific capacitance of 965.3 F g-1 at a scan rate of 10 mV s-1 in 1.0 M H2SO4 solution. In addition, the composite Nyquist plot showed no semicircle at high frequency corresponding to a low equivalent series resistance of 0.35 Ω. At 100 mV s-1, the supercapacitor demonstrated an energy density of 34.5 Wh kg-1 and a power density of 12.4 kW kg-1 based on the total mass of the active materials on both electrodes. To demonstrate the performance, we built an array consisting of three cells connected in series, which lit up a red light emitting diode for five minutes. This simple method holds promise for high-performance yet low-cost electrodes for supercapacitors.

  6. Electromechanical behavior of polyaniline/poly (vinyl alcohol) blend films under static, dynamic and time-dependent strains

    NASA Astrophysics Data System (ADS)

    Akhilesan, S.; Lakshmana Rao, C.; Varughese, S.

    2014-07-01

    We report on the experimentally observed electrical conductivity enhancement in polyaniline/poly (vinyl alcohol) blend films under uniaxial tensile loading. Polyaniline (PANI) is an intrinsically conducting polymer, which does not form stretchable free-standing films easily and hence its electromechanical characterization is a challenge. Blending of PANI with other insulating polymers is a good choice to overcome the processability problem. We report the electromechanical response of solution blended and HCl doped PANI/PVA blends subjected to uniaxial, static, dynamic and time-dependent tensile loading. The demonstrated viscoelastic and morphological contributions of the component polymers to the electrical conductivity behavior in these blends could lead to interesting applications in strain sensors and flexible electronics. The reversibility of the electromechanical response under dynamic strain is found to increase in blends with higher PANI content. Time-dependent conductivity studies during mechanical stress relaxation reveal that variations in the micro-domain ordering and the relative relaxation rate of the individual polymer phases can give rise to interesting electrical conductivity changes in PANI blends. From morphological and electrical conductivity studies, we show that PANI undergoes primary and secondary agglomeration behavior in these blends that contributes to the changes in conductivity behavior during the deformation. A 3D variable range hopping (VRH) process, which uses a deformable core and shell concept based on blend morphology analysis, is used to explain the experimentally observed electromechanical behavior.

  7. Biosensor based on polyaniline-Prussian Blue/multi-walled carbon nanotubes hybrid composites.

    PubMed

    Zou, Yongjin; Sun, Li-Xian; Xu, Fen

    2007-05-15

    In this work, a novel route for fabrication polyaniline (PANI)-Prussian Blue (PB) hybrid composites is proposed by the spontaneous redox reaction in the FeCl(3)-K(3)[Fe(CN)(6)] and the aniline solution. With the introduction of multi-walled carbon nanotubes (MWNTs), the PANI-PB/MWNTs system shows synergy between the PANI-PB and MWNTs which amplified the H(2)O(2) sensitivity greatly. A linear range from 8 x1 0(-8) to 1 x 10(-5)M and a high sensitivity 508.1 8 microA microM cm(2) for H(2)O(2) detection are obtained. The composites also show good stability in neutral solution. A glucose biosensor was further constructed by immobilizing glucose oxidase (GOD) with Nafion and glutaraldehyde on the electrode surface. The performance factors influencing the resulted biosensor were studied in detail. The biosensor exhibits excellent response performance to glucose with the linear range from 1 to 11 mM and a detection limit of 0.01 mM. Furthermore, the biosensor shows rapid response, high sensitivity, good reproducibility, long-term stability and freedom of interference from other co-existing electroactive species. PMID:17141494

  8. Polyaniline/carbon nanotube/CdS quantum dot composites with enhanced optical and electrical properties

    NASA Astrophysics Data System (ADS)

    Goswami, Mrinmoy; Ghosh, Ranajit; Maruyama, Takahiro; Meikap, Ajit Kumar

    2016-02-01

    A new kind of polyaniline/carbon nanotube/CdS quantum dot composites have been developed via in-situ polymerization of aniline monomer in the presence of dispersed CdS quantum dots (size: 2.7-4.8 nm) and multi-walled carbon nanotubes (CNT), which exhibits enhanced optical and electrical properties. The existences of 1st order, 2nd order, and 3rd order longitudinal optical phonon modes, strongly indicate the high quality of synthesized CdS quantum dots. The occurrence of red shift of free exciton energy in photoluminescence is due to size dependent quantum confinement effect of CdS. The conductivity of the composites (for example PANI/CNT/CdS (2 wt.% CdS)) is increased by about 7 of magnitude compared to that of pure PANI indicating a charge transfer between CNT and polymer via CdS quantum dots. This advanced material has a great potential for high-performance of electro-optical applications.

  9. Composite of single walled carbon nanotube and sulfosalicylic acid doped polyaniline: a thermoelectric material

    NASA Astrophysics Data System (ADS)

    Jana Chatterjee, Mukulika; Banerjee, Dipali; Chatterjee, Krishanu

    2016-08-01

    Nanocomposites containing single walled carbon nanotubes (SWCNTs) and highly ordered polyaniline (PANI) have been synthesized employing an in situ polymerization using different weight percentages of single-walled carbon nanotube (SWCNT) as template and aniline as a reactant. The composites show homogeneously dispersed SWCNTs which are uniformly coated with PANI through a strong interface interaction. Structural characterization shows that the PANI cultivated along the surface of the SWCNTs in an ordered manner during the SWCNT-directed polymerization process. Measurements at room temperature displayed a significant enhancement in both the electrical conductivity and thermoelectric power which could be attributed to the more ordered chain structures of the PANI on SWCNT. As a result, the power factor of the composite is improved which increases with temperature. At the same time, the measured value of thermal conductivity at room temperature being lowest among the reported values, has resulted in best ZT at room temperature. The lowest value of thermal conductivity is attributed to the large phonon scattering due to the introduction of nanointerfaces.

  10. Electric properties of carbon nano-onion/polyaniline composites: a combined electric modulus and ac conductivity study

    NASA Astrophysics Data System (ADS)

    Papathanassiou, Anthony N.; Mykhailiv, Olena; Echegoyen, Luis; Sakellis, Ilias; Plonska-Brzezinska, Marta E.

    2016-07-01

    The complex electric modulus and the ac conductivity of carbon nano-onion/polyaniline composites were studied from 1 mHz to 1 MHz at isothermal conditions ranging from 15 K to room temperature. The temperature dependence of the electric modulus and the dc conductivity analyses indicate a couple of hopping mechanisms. The distinction between thermally activated processes and the determination of cross-over temperature were achieved by exploring the temperature dependence of the fractional exponent of the dispersive ac conductivity and the bifurcation of the scaled ac conductivity isotherms. The results are analyzed by combining the granular metal model (inter-grain charge tunneling of extended electron states located within mesoscopic highly conducting polyaniline grains) and a 3D Mott variable range hopping model (phonon assisted tunneling within the carbon nano-onions and clusters).

  11. Facile synthesis of cross linked-chitosan-grafted-polyaniline composite and its Cr(VI) uptake studies.

    PubMed

    Karthik, Rathinam; Meenakshi, Sankaran

    2014-06-01

    In the present investigation, the removal of Cr(VI) ions from aqueous solution using cross linked-chitosan-grafted-polyaniline composite (CCGP) was compared with that of chitosan-grafted-polyaniline (CGP) composite. The composites were characterized using FTIR, SEM-EDX, XRD, DSC, and TGA techniques. Batch equilibrium method was used for the optimization of various equilibrium parameters such as pH, contact time, dosage and initial Cr(VI) ion concentration. The removal efficiency by CCGP composite was found to be higher compared to CGP composite in all the studied conditions. The adsorption process was well described by Freundlich isotherm model for both the composites. The maximum adsorption capacity of CGP and CCGP composite for Cr(VI) ions was 165.6mg/g and 179.2mg/g at 303K. Thermodynamic parameters for the adsorption system were calculated and concluded that the nature of sorption was spontaneous and endothermic in nature. The Cr(VI) adsorption kinetic process was well described by pseudo-second-order kinetic model and the sorption process was being controlled by intraparticle diffusion pattern. Desorption and regeneration experiments of CGP and CCGP composites were performed and reused for more than two consecutive cycles.

  12. Acid diffusion through polyaniline membranes

    SciTech Connect

    Su, T.M.; Huang, S.C.; Conklin, J.A.

    1995-12-01

    Polyaniline membranes in the undoped (base) and doped (acid) forms are studied for their utility as pervaporation membranes. The separation of water from mixtures of propionic acid, acetic acid and formic acid have been demonstrated from various feed compositions. Doped polyaniline displays an enhanced selectivity of water over these organic acids as compared with undoped polyaniline. For as-cast polyaniline membranes a diffusion coefficient (D) on the order of 10{sup -9} cm{sup 2}/sec has been determined for the flux of protons through the membranes using hydrochloric acid.

  13. Effect of electrochemical deposition parameters on the synthesis, structure and properties of polyaniline-polypyrrole composite coatings on steel

    NASA Astrophysics Data System (ADS)

    Rajagopalan, Ramakrishnan

    Polyaniline-polypyrrole composite coatings were formed on low carbon steel using oxalic acid as electrolyte by aqueous potentiostatic electrodeposition. Potentiostatic method is a powerful technique that can force simultaneous polymerization of both pyrrole and aniline. A passive layer of iron (II) oxalate is deposited on the steel surface prior to the formation of composite coatings. The electrochemical deposition process shows three distinct regimes---dissolution of steel, formation of passive layer and formation of polymeric composite coatings. These three regimes have been studied in depth using spectroscopic techniques and electron microscopy. Quantitative analysis of the Current-time transient (I-t) curves show that the nucleation and growth of the passive layer occur by diffusion controlled 3-D instantaneous nucleation. It has also been shown that the morphology and the chemical structure of the composite coatings depend upon the electrochemical deposition (ECD) parameters. The ECD parameters that affect the formation of the coatings are the applied potential; molar feed ratio of monomers and the reaction time. The development of the composite coatings on steel was studied in depth using Infrared Spectroscopy, Scanning Electron Microscopy and X-ray Photoelectron Spectroscopy. For equimolar feed ratio of monomers (aniline and pyrrole), it was shown that polypyrrole starts to form on the steel surface prior to the incorporation of polyaniline. Corrosion resistance and adhesion strength of the coatings were evaluated using DC polarization tests and Lap Joint tests respectively. It was shown that the electrochemical deposition parameters (molar feed ratio of monomers, applied potential and reaction time) influence the corrosion and adhesion performance of the coatings. In general, polyaniline-polypyrrole composite coatings show much better performance than the homopolymers. Especially, the coatings formed using equimolar feed ratio of monomers showed better

  14. Polyaniline/carbon nanofiber and organic charge transfer complex based composite electrode for electroanalytical urea detection

    NASA Astrophysics Data System (ADS)

    Das, Gautam; Yoon, Hyon Hee

    2015-06-01

    A composite electrode based on polyaniline coated modified carbon nanofiber (PANI-mCNF), tetrathiafulvalene-tetracyanoquinodimethane (TTF-TCNQ) and urease (Ur) enzyme was evaluated as biosensor for urea detection. Homogeneous coating of PANI on the surface of mCNF was achieved by oxidative polymerization of anilium ion. Fourier transform infrared (FTIR) spectroscopy and field-emission scanning electron microscopy (FESEM) were used to analyze the structural and morphological characteristics of PANI-mCNF nanocomposite. The biosensor showed excellent electroactivity in neutral and basic medium. A linear response to urea in the concentration range of 0.5-8.4 mM with a correlation coefficient of 0.998, good sensitivity (2.84 µA cm-2 mM-1) and a fast response time (ca. 4 s) was obtained for the biosensor. The minimum detection limit was found to be 3 µM. The biosensor was stable and showed minimal loss in sensitivity, even after two months of storage. The amalgamation of the PANI and CNF synergistically enhances the performance of the biosensor for electroanalytical detection of urea.

  15. Synthesis and electrochemical performance of polyaniline @MnO2/graphene ternary composites for electrochemical supercapacitors

    NASA Astrophysics Data System (ADS)

    Pan, Chao; Gu, Haiteng; Dong, Li

    2016-01-01

    We introduce a facile method to construct new ternary hierarchical nanocomposites by combining MnO2 coated one dimensional (1D) conducting polyaniline (PANI) nanowires with 2D graphene sheets (GNs). The hierarchical nanocomposite structures of PANI@MnO2/GNs (PMGNs) are further proved by X-ray diffraction (XRD), FT-IR, field emission scanning electron microscopy (FESEM), transmission electron microscope (TEM), thermogravimetric analysis (TGA), and X-ray photoelectron spectroscopy (XPS). The electrochemical characteristics of the electrodes made of the hierarchical structured PMGNs materials are determined by the CV and galvanostatic measurements. These electrochemical tests indicate that electrodes made of the nanostructured PMGNs exhibit an improved reversible capacitance of 695 F g-1 after 1000 cycles at a high current density of 4 A g-1. The ternary composites possess higher electrochemical capacitance than each individual component as supercapacitor electrode materials. Such intriguing electrochemical performance is mainly attributed to the synergistic effects of MnO2, PANI and graphene. The hierarchical ternary nanocomposites show excellent electrochemical properties for energy storage applications, which evidence their potential application as supercapacitors.

  16. Development of a polyaniline-lignocellulose composite for optimal adsorption of Congo red.

    PubMed

    Debnath, Sushanta; Ballav, Niladri; Maity, Arjun; Pillay, Kriveshini

    2015-04-01

    A polyaniline lignocellulose composite (PLC) was synthesized and used in the removal of Congo red (CR) from aqueous solution. The adsorption process showed good fits to both the pseudo-second-order and pseudo-first-order models and the Redlich Peterson isotherm. Boundary layer diffusion was the rate-limiting step. The adsorption was spontaneous and endothermic. The combined effect of pH and initial dye concentration was antagonistic; the combined effect of initial dye concentration and temperature was synergistic, while the combined effect of pH and temperature was reciprocal. The maximum CR adsorption capacity of PLC was evaluated as 1672.5 mg g(-1). The optimal removal was calculated as 99.85% at pH 4.29, initial dye concentration of 28.5 mg L(-1) and adsorbent dosage of 0.69 g L(-1). The predicted removal capacity showed a good correlation to the experimental results. PLC has demonstrated a superior adsorption capacity to many other adsorbents reported and could be used as an efficient adsorbent for CR removal from industrial wastewater.

  17. Synthesis of highly conductive cotton fiber/nanostructured silver/polyaniline composite membranes for water sterilization application

    NASA Astrophysics Data System (ADS)

    Abu-Thabit, Nedal Y.; Basheer, Rafil A.

    2014-09-01

    Electrically conductive composite membranes (ECCMs) composed of cotton fibers, conductive polyaniline and silver nanostructures were prepared and utilized as electrifying filter membranes for water sterilization. Silver metal and polyaniline were formed in situ during the oxidative polymerization of aniline monomers in the presence of silver nitrate as weak oxidizing agent. The reaction was characterized by long induction period and the morphology of the obtained ECCMs contained silver nanoparticles and silver flakes of 500-1000 nm size giving a membrane electrical resistance in the range of 10-30 Ohm sq-1. However, when dimethylformamide (DMF) was employed as an auxiliary reducing agent to trigger and speed up the polymerization reaction, silver nanostructures such as wires, ribbons, plates were formed and were found to be embedded between polyaniline coating and cotton fibers. These ECCMs exhibited a slightly lower resistance in the range of 2-10 Ohm sq.-1 and, therefore, were utilized for the fabrication of a bacteria inactivation device. When water samples containing 107-108 CFU mL-1 E. coli bacteria were passed through the prepared ECCMs by gravity force, with a filtration rate of 0.8 L h-1 and at an electric potential of 20 V, the fabricated device showed 92% bacterial inactivation efficiency. When the treated solution was passed through the membrane for a second time under the same conditions, no E. coli bacteria was detected.

  18. New membrane technologies: Nanotube membranes for biotechnological applications and polyaniline films for corrosion inhibition

    NASA Astrophysics Data System (ADS)

    Gasparac, Rahela

    polyaniline (PANI) films passivate stainless steel surfaces in highly corrosive H2SO 4 solution. A variety of experimental methods including measurements of the open circuit potential, Auger depth profiling, and the scanning reference electrode technique (SRET) was used. These studies have shown that passivation is achieved because the oxidized and protically-doped emeraldine-salt form of PANI holds the potential of the underlying stainless steel electrode in the passive region. Because of this electrostatic mechanism of corrosion inhibition, the entire stainless steel surface does not have to be coated with PANI in order to achieve passivation.

  19. An Introduced Hybrid Graphene/Polyaniline Composites for Improvement of Supercapacitor

    NASA Astrophysics Data System (ADS)

    Tayel, Mazhar B.; Soliman, Moataz M.; Ebrahim, Shaker; Harb, Mohamed E.

    2016-01-01

    Supercapacitors represent an attractive alternative for portable electronics and automotive applications due to their high capacitance, specific power and extended life. In fact, the growing demand of portable systems and hybrid electric vehicles, memory protection in complementary metal-oxide-semiconductor (CMOS), logic circuit, videocassette recorders (VCRs), compact disc (CD) players, personal computers (PCs), uninterruptible power supply (UPS) in security alarm systems, remote sensing, smoke detectors, etc. require high power in short-term pulses. Therefore, in the last 20 years, supercapacitors have been required for the development of large and small devices driven by electrical power. In this paper, graphene oxide (GO) was synthesized by improved Hummers method. Two polyaniline (PANI)/graphene oxide nanocomposites electrode materials were prepared from aniline, GO and ammoniumpersulfate (APS) by in situ chemical polymerization with the mass ratios (mGO:mAniline) 10:90 and 30: 70 in ice bath. The crystal structure and the surface topography of all materials were characterized by means of x-ray diffraction (XRD), Fourier transform infrared spectrum (FTIR), Raman spectroscopy and scanning electron microscopy (SEM). The electrochemical properties of the composites were evaluated by cyclic voltammetry (CV), charge-discharge measurements and electrical impedance spectroscopy (EIS), respectively. The results show that the composites have similar and enhanced cyclic voltammetry performance compared with pure PANI based electrode material. The graphene/PANI composite synthesized with the mass ratio (mANI:mGO) 90:10 possessed good capacitive behavior with a specific capacitance as high as 1509.35 F/g at scan rate of 1 mV/s in scanning potential window from -0.8 V to 0.8 V.

  20. Enhanced thermal stability under DC electrical conductivity retention and visible light activity of Ag/TiO₂@polyaniline nanocomposite film.

    PubMed

    Ansari, Mohd Omaish; Khan, Mohammad Mansoob; Ansari, Sajid Ali; Raju, Kati; Lee, Jintae; Cho, Moo Hwan

    2014-06-11

    The development of organic-inorganic photoactive materials has resulted in significant advancements in heterogeneous visible light photocatalysis. This paper reports the synthesis of visible light-active Ag/TiO2@Pani nanocomposite film via a simple biogenic-chemical route. Electrically conducting Ag/TiO2@Pani nanocomposites were prepared by incorporating Ag/TiO2 in N-methyl-2-pyrrolidone solution of polyaniline (Pani), followed by the preparation of Ag/TiO2@Pani nanocomposite film using solution casting technique. The synthesized Ag/TiO2@Pani nanocomposite was confirmed by UV-visible spectroscopy, photoluminescence spectroscopy, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and thermogravimetric analysis. The Ag/TiO2@Pani nanocomposite film showed superior activity towards the photodegradation of methylene blue under visible light compared to Pani film, even after repeated use. Studies on the thermoelectrical behavior by DC electrical conductivity retention under cyclic aging techniques showed that the Ag/TiO2@Pani nanocomposite film possessed a high combination of electrical conductivity and thermal stability. Because of its better thermoelectric performance and photodegradation properties, such materials might be a suitable advancement in the field of smart materials in near future.

  1. A Simple Visual Ethanol Biosensor Based on Alcohol Oxidase Immobilized onto Polyaniline Film for Halal Verification of Fermented Beverage Samples

    PubMed Central

    Kuswandi, Bambang; Irmawati, Titi; Hidayat, Moch Amrun; Jayus; Ahmad, Musa

    2014-01-01

    A simple visual ethanol biosensor based on alcohol oxidase (AOX) immobilised onto polyaniline (PANI) film for halal verification of fermented beverage samples is described. This biosensor responds to ethanol via a colour change from green to blue, due to the enzymatic reaction of ethanol that produces acetaldehyde and hydrogen peroxide, when the latter oxidizes the PANI film. The procedure to obtain this biosensor consists of the immobilization of AOX onto PANI film by adsorption. For the immobilisation, an AOX solution is deposited on the PANI film and left at room temperature until dried (30 min). The biosensor was constructed as a dip stick for visual and simple use. The colour changes of the films have been scanned and analysed using image analysis software (i.e., ImageJ) to study the characteristics of the biosensor's response toward ethanol. The biosensor has a linear response in an ethanol concentration range of 0.01%–0.8%, with a correlation coefficient (r) of 0.996. The limit detection of the biosensor was 0.001%, with reproducibility (RSD) of 1.6% and a life time up to seven weeks when stored at 4 °C. The biosensor provides accurate results for ethanol determination in fermented drinks and was in good agreement with the standard method (gas chromatography) results. Thus, the biosensor could be used as a simple visual method for ethanol determination in fermented beverage samples that can be useful for Muslim community for halal verification. PMID:24473284

  2. Electrosynthesis of polyaniline-mutilwalled carbon nanotube nanocomposite films in the presence of sodium dodecyl sulfate for glucose biosensing

    NASA Astrophysics Data System (ADS)

    Huyen Le, Trong; Thang Trinh, Ngoc; Nguyen, Le Huy; Binh Nguyen, Hai; Nguyen, Van Anh; Tran, Dai Lam; Dung Nguyen, Tuan

    2013-06-01

    Polyaniline-mutilwalled carbon nanotube (PANi-MWCNT) nanocomposites were electropolymerized in the presence of sodium dodecyl sulfate (SDS) onto interdigitated platinum-film planar microelectrodes (IDμE). The MWCNTs were first dispersed in SDS solution then mixed with aniline and H2SO4. This mixture was used to electro-synthesize PANi-MWCNT films with potentiostatic method at E = + 0.90 V (versus SCE). The PANi-MWCNT films were characterized by cyclic voltammetry (CV) and scanning electron microscopy (SEM). The results show that the PANi-MWCNT films have a high electroactivity, and a porous and branched structure that can increase the specific surface area for biosensing application. In this work the PANi-MWCNT films were applied for covalent immobilization of glucose oxidase (GOx) via glutaraldehyde agent. The GOx/PANi-MWCNT/IDμE was studied using cyclic voltammetric and chronoamperometric techniques. The effect of several interferences, such as ascorbic acid (AA), uric acid (UA), and acetaminophen (AAP) on the glucosensing at +0.6 V (versus SCE) is not significant. The time required to reach 95% of the maximum steady-state current was less than 5 s. A linear range of the calibration curve for the glucose concentration lies between 1 and 12 mM which is a suitable level in the human body.

  3. A simple visual ethanol biosensor based on alcohol oxidase immobilized onto polyaniline film for halal verification of fermented beverage samples.

    PubMed

    Kuswandi, Bambang; Irmawati, Titi; Hidayat, Moch Amrun; Jayus; Ahmad, Musa

    2014-01-27

    A simple visual ethanol biosensor based on alcohol oxidase (AOX) immobilised onto polyaniline (PANI) film for halal verification of fermented beverage samples is described. This biosensor responds to ethanol via a colour change from green to blue, due to the enzymatic reaction of ethanol that produces acetaldehyde and hydrogen peroxide, when the latter oxidizes the PANI film. The procedure to obtain this biosensor consists of the immobilization of AOX onto PANI film by adsorption. For the immobilisation, an AOX solution is deposited on the PANI film and left at room temperature until dried (30 min). The biosensor was constructed as a dip stick for visual and simple use. The colour changes of the films have been scanned and analysed using image analysis software (i.e., ImageJ) to study the characteristics of the biosensor's response toward ethanol. The biosensor has a linear response in an ethanol concentration range of 0.01%-0.8%, with a correlation coefficient (r) of 0.996. The limit detection of the biosensor was 0.001%, with reproducibility (RSD) of 1.6% and a life time up to seven weeks when stored at 4 °C. The biosensor provides accurate results for ethanol determination in fermented drinks and was in good agreement with the standard method (gas chromatography) results. Thus, the biosensor could be used as a simple visual method for ethanol determination in fermented beverage samples that can be useful for Muslim community for halal verification.

  4. Simple and mass-produced mechanochemical preparation of graphene nanosheet/polyaniline composite assisted with bifunctional ionic liquid

    NASA Astrophysics Data System (ADS)

    Lu, Xiangjun; Dou, Hui

    2016-05-01

    Graphene nanosheet/polyaniline (GNS/PANI) composite was prepared by a simple and mass-produced mechanochemical method, where the functionalized ionic liquid 1-(3-sulfonic acid) propyl-3-methylimidazolium hydrogen sulfate conducts as not only the dispersant of GNS but also the dopant of PANI. The GNS/PANI composite characterized by Fourier transformation infrared spectra, UV-Vis spectra and X-ray diffraction shows that the resulting PANI in composite is in its doped, conductive emeraldine oxidation state. Scanning electron microscope images reveal that the GNS/PANI composite with PANI uniformly coated on the surface of GNS is randomly stacking. Compared with pure PANI, the GNS/PANI composite has higher electrical conductivity, better thermal stability and electrochemical activity due to the presence of GNS.

  5. MnO2 Nanorods Intercalating Graphene Oxide/Polyaniline Ternary Composites for Robust High-Performance Supercapacitors

    PubMed Central

    Han, Guangqiang; Liu, Yun; Zhang, Lingling; Kan, Erjun; Zhang, Shaopeng; Tang, Jian; Tang, Weihua

    2014-01-01

    New ternary composites of MnO2 nanorods, polyaniline (PANI) and graphene oxide (GO) have been prepared by a two-step process. The 100 nm-long MnO2 nanorods with a diameter ~20 nm are conformably coated with PANI layers and fastened between GO layers. The MnO2 nanorods incorporated ternary composites electrode exhibits significantly increased specific capacitance than PANI/GO binary composite in supercapacitors. The ternary composite with 70% MnO2 exhibits a highest specific capacitance reaching 512 F/g and outstanding cycling performance, with ~97% capacitance retained over 5000 cycles. The ternary composite approach offers an effective solution to enhance the device performance of metal-oxide based supercapacitors for long cycling applications. PMID:24769835

  6. Facile synthesis of multifunctional multiwalled carbon nanotubes/Fe{sub 3}O{sub 4} nanoparticles/polyaniline composite nanotubes

    SciTech Connect

    Kong, Lirong; Lu Xiaofeng; Zhang Wanjin

    2008-03-15

    With an average diameter of 100-150 nm, composite nanotubes of polyaniline (PANI)/multiwalled carbon nanotubes (MWNTs) containing Fe{sub 3}O{sub 4} nanoparticles (NPs) were synthesized by a two-step method. First, we synthesized monodispersed Fe{sub 3}O{sub 4} NPs (d=17.6 nm, {sigma}=1.92 nm) on the surface of MWNTs and then decorated the nanocomposites with a PANI layer via a self-assembly method. SEM and TEM images indicated that the obtained samples had the morphologies of nanotubes. The molecular structure and composition of MWNTs/Fe{sub 3}O{sub 4} NPs/PANI nanotubes were characterized by Fourier transform infrared spectra (FTIR), energy dispersive X-ray spectrometry (EDX), X-ray photoelectron spectra (XPS), X-ray diffraction (XRD) and Raman spectra. UV-vis spectra confirmed the existence of PANI and its response to acid and alkali. As a multifunctional material, the conductivity and magnetic properties of MWNTs/Fe{sub 3}O{sub 4} NPs/PANI composites nanotubes were also investigated. - Graphical abstract: The work on preparing nanocomposites has been too much, but few reports were about synthesizing one-dimensional nanocomposite of three different nanoscale materials. In our work, we prepared one-dimensional multiwalled carbon nanotubes/Fe{sub 3}O{sub 4} particles/polyaniline composite nanotubes and studied their conductive and magnetic properties.

  7. Polyaniline nanowire synthesis templated by DNA

    NASA Astrophysics Data System (ADS)

    Nickels, Patrick; Dittmer, Wendy U.; Beyer, Stefan; Kotthaus, Jörg P.; Simmel, Friedrich C.

    2004-11-01

    DNA-templated polyaniline nanowires and networks are synthesized using three different methods. The resulting DNA/polyaniline hybrids are fully characterized using atomic force microscopy, UV-vis spectroscopy and current-voltage measurements. Oxidative polymerization of polyaniline at moderate pH values is accomplished using ammonium persulfate as an oxidant, or alternatively in an enzymatic oxidation by hydrogen peroxide using horseradish peroxidase, or by photo-oxidation using a ruthenium complex as photo-oxidant. Atomic force microscopy shows that all three methods lead to the preferential growth of polyaniline along DNA templates. With ammonium persulfate, polyaniline can be grown on DNA templates already immobilized on a surface. Current-voltage measurements are successfully conducted on DNA/polyaniline networks synthesized by the enzymatic method and the photo-oxidation method. The conductance is found to be consistent with values measured for undoped polyaniline films.

  8. Gold-polyaniline composites: Part II. Effects of nanometer sized particles

    SciTech Connect

    Smith, Jon A.; Josowicz, Mira A.; Engelhard, Mark H.; Baer, Donald R.; Janata, Jiri

    2005-09-01

    The amount of electronic charge transferred between gold particles and polyaniline depends not only on the electron affinity of the two materials but also on the size of the gold particles. As measured by X-ray photoelectron spectroscopy, for particles < 5 nm the binding energy of the electrons is size dependent. This nano-effect has its origin in the electrostatics of particles. It is demonstrated as a measurable shift of the binding energy of the Au4f7/2 photoelectrons emitted from Au particles embedded in a polyaniline matrix. Gold nanoparticle size was evaluated by high resolution transmission electron microscopy.

  9. Virtues of composite structures in electrode modification. Preparation and properties of poly(aniline)/nafion composite films. Technical report No. 3, September 1987-June 1988

    SciTech Connect

    Orata, D.O.; Buttry, D.A.

    1988-07-09

    Poly(aniline) (PA) is electropolymerized within thin films of precast Nafion on gold or glassy carbon electrodes. The quartz crystal microbalance (QCM) is used to aid in identification of the ionic species that undergo transport during switching of the PA between its insulating and conducting forms. The QCM frequency changes observed in solutions containing various cationic species suggest that cation transport is dominant for these composite structures. In acidic solution, a consequence of the high transport number for the proton in the composite films is shown to be an enhanced switching rate relative to the simple (non-composite) PA film. The composite PA films appear to be less resistive and therefore more electrochemically well behaved over a wider pH range than the simple PA films.

  10. Thickness-self-controlled synthesis of porous transparent polyaniline-reduced graphene oxide composites towards advanced bifacial dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Wang, Yu-Sheng; Li, Shin-Ming; Hsiao, Sheng-Tsung; Liao, Wei-Hao; Yang, Shin-Yi; Tien, Hsi-Wen; Ma, Chen-Chi M.; Hu, Chi-Chang

    2014-08-01

    A powerful synthesis strategy is proposed for fabricating porous polyaniline-reduced graphene oxide (PANI-RGO) composites with transparency up to 80% and thickness from 300 to 1000 nm for the counter electrode (CE) of bifacial dye-sensitizing solar cells (DSSCs). The first step is to combine the in-situ positive charge transformation of graphene oxide (GO) through aniline (ANI) prepolymerization and the electrostatic adsorption of ANI oligomer-GO to effectively control the thickness of ultrathin PANI-GO films by adjusting pH of the polymerization media. In the second step, PANI-GO films are reduced with hydroiodic acid to simultaneously enhance the apparent redox activity for the I3-/I- couple and their electronic conductivity. Incorporating the RGO increases the transparency of PANI and facilitates the light-harvesting from the rear side. A DSSC assembled with such a transparent PANI-RGO CE exhibits an excellent efficiency of 7.84%, comparable to 8.19% for a semi-transparent Pt-based DSSC. The high light-harvesting ability of PANI-RGO enhances the efficiency retention between rear- and front-illumination modes to 76.7%, compared with 69.1% for a PANI-based DSSC. The higher retention reduces the power-to-weight ratio and the total cost of bifacial DSSCs, which is also promising in other applications, such as windows, power generators, and panel screens.

  11. Graphene/polyaniline/poly(4-styrenesulfonate) hybrid film with uniform surface resistance and its flexible dipole tag antenna application.

    PubMed

    Shin, Keun-Young; Cho, Sunghun; Jang, Jyongsik

    2013-11-25

    A graphene/polyaniline/poly(4-styrenesulfonate) (G/PANI/PSS)-based conducting paste is successfully fabricated by introducing a PANI/PSS nanofiller into a multilayer graphene matrix by mechanical blending. As a compatibilizer, the PSS binder increases the dispersibility, interfacial interactions, and mechanical interlocking between the multilayer graphene matrix and PANI, thereby allowing surface resistance with narrow distribution. High concentrations of this PSS binder, obtained using ex situ polymerization, further improve the adhesion of the hybrid film to a flexible substrate. The minimum surface resistance of the screen-printed G/PANI/PSS hybrid film is approximately 10 Ω sq(-1) for a 70 μm uniform thickness. When bent to angles of -30°, the flexible hybrid film exhibits an approximately 6% decrease in surface resistance. The surface resistance after 500 bending cycles increases by only 10 Ω sq(-1) , which is 14 times that of smaller, graphene-based thin films. The micropatterned, screen-printed G/PANI/PSS hybrid film is evaluated as a practical dipole tag antenna. High-resolution patterns are formed in the hybrid film by the inherently high surface tension and the properties of grains within the domain-based structure. The G/PANI/PSS-based dipole tag antenna has a bandwidth of 28.7 MHz, a high transmitted power efficiency of 98.5%, and a recognition distance of 0.42 m at a mean frequency of 910 MHz. These characteristics indicate that the G/PANI/PSS-based dipole tag antenna could be used as a signal-receiving apparatus, much like a radio-frequency identification tag, for detecting nearby objects. PMID:23650263

  12. A novel microextractor stick (polyaniline/zinc film/stainless steel) for polycyclic aromatic hydrocarbons in water.

    PubMed

    Chaiphet, Thitiphan; Bunkoed, Opas; Thammakhet, Chongdee; Thavarungkul, Panote; Kanatharana, Proespichaya

    2014-01-01

    A novel microextractor stick (MES) has been developed for the determination of trace amounts of polycyclic aromatic hydrocarbons (PAHs) in water samples. The proposed MES was prepared by electrodepositing a Zn-film onto a stainless steel stick followed by a coating with polyaniline (PANI) sorptive layers. This PANI/Zn-film/stainless steel stick produced a large surface area, provided a high extraction efficiency (82.0 ± 6.2% to 111.0 ± 7.5% recovery) of spiked chrysene (Chry) and benzo(a)pyrene (BaP). This MES is cost-effective, easy to prepare, robust and provides a good stick-to-stick reproducibility (n = 10) with a relative standard deviation of less than 10%. The effect of various parameters on the efficiency of extraction of PAHs were optimized, including the extraction time, extraction and desorption stirring speeds, volume of desorption solvent and desorption time. Under the optimum conditions, the limit of detection (S/N ≥ 3) and limit of quantification (S/N ≥ 10) of both Chry and BaP were 0.05 and 0.12 μg L(-1), respectively. The developed MES was successfully applied to determine PAHs in real water samples. PMID:24766589

  13. Polyaniline: Factors affecting conductivity and mechanical properties

    SciTech Connect

    Scherr, E.M.

    1993-01-01

    The main objectives of this study were: (a) to study electronic and mechanical properties of films of the conducting polymer, polyaniline, in the doped and undoped emeraldine oxidation state, (b) to study how the electronic and mechanical properties were modified through mechanical stretch-orientation of the films, (c) to study the effect of water vapor on the conductivity of stretched protonic acid doped films, (d) to observe changes in tensile strength and Young's modulus when selected plasticizers were introduced into the films, (e) to observe, using UV/Vis spectroscopy, the effect that neutral salts in the doping media have on the doping level of thin, optically transparent films of polyaniline, (f) to use thin, optically transparent films to spectroscopically study (by UV/Vis) hysteresis in the doping and undoping behavior of polyaniline. The significant results and conclusions are: (a) mechanical stretch-orientation of polyaniline increased the tensile strength of emeraldine base films, (b) the conductivity of doped films of polyaniline was increased approximately two orders of magnitude by stretch-orientation (four-fold elongation) from [approximately]5 S/cm to [approximately]90 S/cm, (c) an increase in the relative percent crystallinity (by x-ray diffraction) upon stretch-orientation of emeraldine base films, (d) the removal of water vapor was found to decrease the conductivity of stretched emeraldine, (e) both tensile strength and Young's modulus are decreased by the introduction of plasticizers and [open quotes]dopant plasticizers[close quotes] into the films, (f) no loss in conductivity was observed due to the addition of plasticizers, (g) the presence of neutral salts in the doping media increased the doping level of thin films of polyaniline, (h) observed hysteresis upon doping and undoping thin polyaniline films is due to irreversible morphological changes that take place in polyaniline upon doping and undoping.

  14. Choline-sensing carbon paste electrode containing polyaniline (pani)-silicon dioxide composite-modified choline oxidase.

    PubMed

    Özdemir, Merve; Arslan, Halit

    2014-02-01

    In this study, a novel carbon paste electrode (CPE) was prepared using the salt form of polyaniline (pani)-silicon dioxide composite that is sensitive to choline. Choline oxidase (ChO) enzyme was immobilized to modified carbon paste electrode (MCPE) by cross-linking with glutaraldehyde. Determination of choline was carried out by the oxidation of enzymatically produced H2O2 at 0.4 V vs. Ag/AgCl. The effects of pH and temperature were investigated, and the optimum parameters were found to be 6.0 and 60°C, respectively. The linear working range of the electrode was 5.0 × 10(-7)-1.0 × 10(-5) M, R(2) = 0.922. The storage stability and operation stability of the enzyme electrode were also studied.

  15. Conduction mechanism in Polyaniline-flyash composite material for shielding against electromagnetic radiation in X-band & Ku band

    NASA Astrophysics Data System (ADS)

    Singh, Avanish Pratap; Anoop Kumar, S.; Chandra, Amita; Dhawan, S. K.

    2011-06-01

    β-Naphthalene sulphonic acid (β-NSA) doped polyaniline (PANI)-flyash (FA) composites have been prepared by chemical oxidative polymerization route whose conductivity lies in the range 2.37-21.49 S/cm. The temperature dependence of electrical conductivity has also been recorded which shows that composites follow Mott's 3D-VRH model. SEM images demonstrate that β-NSA leads to the formation of the tubular structure with incorporated flyash phase. TGA studies show the improvement in thermal stability of composites with increase in loading level of flyash. Complex parameters i.e. permittivity (ɛ* = ɛ'- iɛ″) and permeability (μ*=μ'- iμ″) of PANI-FA composites have been calculated from experimental scattering parameters (S11 & S21) using theoretical calculations given in Nicholson-Ross and Weir algorithms. The microwave absorption properties of the composites have been studied in X-band (8.2 - 12.4 GHz) & Ku-Band (12.4 - 18 GHz) frequency range. The maximum shielding effectiveness observed was 32dB, which strongly depends on dielectric loss and volume fraction of flyash in PANI matrix.

  16. The preparation and performance of calcium carbide-derived carbon/polyaniline composite electrode material for supercapacitors

    NASA Astrophysics Data System (ADS)

    Zheng, Liping; Wang, Ying; Wang, Xianyou; Li, Na; An, Hongfang; Chen, Huajie; Guo, Jia

    Calcium carbide (CaC 2)-derived carbon (CCDC)/polyaniline (PANI) composite materials are prepared by in situ chemical oxidation polymerization of an aniline solution containing well-dispersed CCDC. The structure and morphology of CCDC/PANI composite are characterized by Fourier infrared spectroscopy (FTIR), scanning electron microscope (SEM), transmission electron microscopy (TEM) and N 2 sorption isotherms. It has been found that PANI was uniformly deposited on the surface and the inner pores of CCDC. The supercapacitive behaviors of the CCDC/PANI composite materials are investigated with cyclic voltammetry (CV), galvanostatic charge/discharge and cycle life measurements. The results show that the CCDC/PANI composite electrodes have higher specific capacitances than the as grown CCDC electrodes and higher stability than the conducting polymers. The capacitance of CCDC/PANI composite electrode is as high as 713.4 F g -1 measured by cyclic voltammetry at 1 mV s -1. Besides, the capacitance retention of coin supercapacitor remained 80.1% after 1000 cycles.

  17. A novel reducing graphene/polyaniline/cuprous oxide composite hydrogel with unexpected photocatalytic activity for the degradation of Congo red

    NASA Astrophysics Data System (ADS)

    Miao, Jie; Xie, Anjian; Li, Shikuo; Huang, Fangzhi; Cao, Juan; Shen, Yuhua

    2016-01-01

    In this work, a novel reducing graphene/polyaniline/cuprous oxide (RGO/PANI/Cu2O) composite hydrogel with a 3D porous network has been successfully prepared via a one-pot method in the presence of cubic Cu2O nanoparticles. The as-synthesized ternary composites hydrogel shows unexpected photocatalytic activity such that Congo red (CR) degradation efficiency can reaches 97.91% in 20 min under UV-vis light irradiation, which is much higher than that of either the single component (Cu2O nanoparticles), or two component systems (RGO/Cu2O composite hydrogel and PANI/Cu2O nanocomposites). Furthermore, the ternary composite hydrogel exhibits high stability and do not show any significant loss after five recycles. Such outstanding photocatalytic activity of the RGO/PANI/Cu2O composite hydrogel was ascribed to the high absorption ability of the product for CR and the synergic effect among RGO, PANI and Cu2O in photocatalytic process. The product of this work would provide a new sight for the construction of UV-vis light responsive photocatalyst with high performance.

  18. Synthesis, structure and electrochemical properties of polyaniline/MoO{sub 3} nanobelt composite for lithium battery

    SciTech Connect

    Mohan, Varishetty Madhu; Chen, Wen; Murakami, Kenji

    2013-02-15

    Graphical abstract: Hydrothermal method was introduced for the synthesis of MoO{sub 3} nanobelts and polyaniline (PANI)/MoO{sub 3} nanobelt composites. The structure and morphology of the samples were studied by X-ray diffraction (XRD), Fourier transform infrared radiation (FTIR), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) analysis. We can see the presence of polyaniline on the MoO{sub 3} nanobelts surface in the TEM pictures as shown in Fig. (a). The pure MoO{sub 3} nanobelts exhibit the initial specific capacity 276 mAhg{sup −1}, whereas PANI/MoO{sub 3} nanobelt composite shows little low initially 228 mAhg{sup −1} after that it has more stabilized specific capacity with increasing cycle numbers as shown in Fig. (b). The cyclic voltammograms of the PANI/MoO{sub 3} nanobelt composite show better cyclic performance compared to pure MoO{sub 3} nanobelts. The electrochemical impedance spectres were studied for both the pure and PANI/MoO{sub 3} samples at 2.0 and 3.5 potentials. The role of the PANI polymeric component of the composite material seems to be the stabilization of the specific capacity due to probable homogeneous distribution of the induced stress during cycling. Display Omitted Highlights: ► Hydrothermal synthesis of MoO{sub 3}, PANI/MoO{sub 3} nanobelts. ► Samples were characterised by XRD, FTIR, DSC, SEM, TEM, CV and impedance. ► MoO{sub 3} nanobelts cathode battery shows initial specific capacity 276 mAhg{sup −1}. ► PANI/MoO{sub 3} nanobelts show initial specific capacity 228 mAhg{sup −1} but high stability. ► PANI/MoO{sub 3} sample studies by impedance at the potentials of 2.0 and 3.5 V. -- Abstract: The MoO{sub 3} nanobelts and polyaniline (PANI)/MoO{sub 3} nanobelt composite were synthesized using hydrothermal method. The crystal structure and morphology of the samples were studied by X-ray diffraction (XRD), Fourier transform infrared radiation (FTIR), scanning electron microscopy (SEM) and

  19. Hollow-spherical composites of Polyaniline/Cobalt Sulfide/Carbon nanodots with enhanced magnetocapacitance and electromagnetic wave absorption capabilities

    NASA Astrophysics Data System (ADS)

    Ge, Chuanjun; Zhang, Xiang; Liu, Jian; Jin, Feng; Liu, Jichang; Bi, Hong

    2016-08-01

    Hollow-spherical composites of polyaniline/cobalt sulfide/carbon nanodots (PANI/CoS/CDs-0.5T) have been synthesized by in situ polymerization under an applied magnetic field (MF) of 0.5 T. As a control, PANI/CoS/CDs-0T composites have been synthesized without a MF. Both composites acting as electrodes present obvious magnetocapacitances at a scan rate of 100 mV s-1 while the electrochemical cell tested under an external MF of 0.5 T. Notably, PANI/CoS/CDs-0.5T composites show larger magnetocapacitances than PANI/CoS/CDs-0T composites at different scan rates from 5 to 100 mV s-1. Electrochemical impedance spectroscopy (EIS) results indicate that MF can reduce charge transfer resistance at electrode/electrolyte interface. More importantly, PANI/CoS/CDs-0.5T composites show a much stronger electromagnetic wave (EMW) absorbing capability than PANI/CoS/CDs-0T in the range of 2-18 GHz which is attributed to an increased dielectric loss and a magnetic loss in low frequency range of 2-12.5 GHz. MF-induced ferromagnetic nanodomains of Co2+ clusters in the PANI/CoS/CDs-0.5T composites increase the complex permittivity and create more interfacial polarizations or the Maxwell-Wagner effect, which leads to increased dielectric loss. Compared with PANI/CoS/CDs-0T composites with diamagnetic behaviour, MF-induced weak ferromagnetism of CoS in the PANI/CoS/CDs-0.5T composites has caused additional magnetic loss. This work provides an efficient way for modulating electrochemical or electromagnetic properties of inorganic/polymer nanocomposites by employing an external MF.

  20. Interpenetrating polyaniline-gold electrodes for SERS and electrochemical measurements

    NASA Astrophysics Data System (ADS)

    West, R. M.; Semancik, S.

    2016-11-01

    Facile fabrication of nanostructured electrode arrays is critical for development of bimodal SERS and electrochemical biosensors. In this paper, the variation of applied potential at a polyaniline-coated Pt electrode is used to selectivity deposit Au on the polyaniline amine sites or on the underlying Pt electrode. By alternating the applied potential, the Au is grown simultaneously from the top and the bottom of the polyaniline film, leading to an interpenetrated, nanostructured polymer-metal composite extending from the Pt electrode to the electrolyte solution. The resulting films have unique pH-dependent electrochemical properties, e.g. they retain electrochemical activity in both acidic and neutral solutions, and they also include SERS-active nanostructures. By varying the concentration of chloroaurate used during deposition, Au nanoparticles, nanodendrites, or nanosheets can be selectively grown. For the films deposited under optimal conditions, using 5 mmol/L chloroaurate, the SERS enhancement factor for Rhodamine 6G was found to be as high as 1.1 × 106 with spot-to-spot and electrode-to-electrode relative standard deviations as low as 8% and 12%, respectively. The advantages of the reported PANI-Au composite electrodes lie in their facile fabrication, enabling the targeted deposition of tunable nanostructures on sensing arrays, and their ability to produce orthogonal optical and electrochemical analytical results.

  1. Removal of aqueous Hg(II) and Cr(VI) using phytic acid doped polyaniline/cellulose acetate composite membrane.

    PubMed

    Li, Renjie; Liu, Lifen; Yang, Fenglin

    2014-09-15

    Conductive composite membrane-phytic acid (PA) doped polyaniline (PANI)/cellulose acetate (CA) (PANI-PA/CA) was prepared in a simple and environmental-friendly method, in which aniline was blended with CA/PA solution and polymerized before the phase conversion. The resultant composite membranes were characterized by SEM, EDX, FTIR-ATR, BET and electrical resistance measurements. When used as adsorbent for Hg(II) and Cr(VI) ions, the prepared composite membrane exhibits excellent adsorption capability. The adsorption of Hg(II) and Cr(VI) follows a pseudo-second-order kinetic model and best fits the Langmuir isotherm model, with the maximum adsorption capacity reaching 280.11 and 94.34 mg g(-1), respectively. The heavy metal loaded composite membrane can be regenerated and reused after treatment with acid or alkali solution, making it a promising and practical adsorbent for Hg(II) and Cr(VI) removal. Tests with river water were also carried out, indicating good performance and application.

  2. Effect of diameter of cellulosic nano-fiber on conductivity of poly(aniline sulfonic acid) composites

    NASA Astrophysics Data System (ADS)

    Konagaya, S.; Shimizu, K.; Terada, M.; Yamada, T.; Sanada, K.; Numata, O.; Sugino, G.

    2014-05-01

    The authors have been studying the effect of cellulosic nano-fiber (CeNF) with the diameter of less than 30 nm and the length of a few micrometers on the conductivity of the conductive polymer composites (PAS/PEs/CeNF) prepared from poly(aniline sulfonic acid) (PAS), a water dispersible polyester (PEs) and CeNF and confirmed that CeNF was effective for the enhancement of their conductivity, and that the conductivity enhancement was attributable to the strong adsorbing ability of CeNF to PAS molecules. Thiner CeNF has so larger surface area that it is expected to adsorb more PAS molecules on its surface, which possibly lead to further conductivity enhancement of the composites. The authors prepared thinner CeNF with the size of 16 nm by the use of ultrasonic dispersing machine. It was clarified that the thinner CeNF had a higher adsorbing ability to PAS molecules and a larger effect on the conductivity enhancement of PAS/PEs/CeNF composites.

  3. A Ternary Polyaniline/Active Carbon/Lithium Iron Phosphate Composite as Cathode Material for Lithium Ion Battery.

    PubMed

    Wang, Xiaohong; Zhang, Wuxing; Huang, Yunhui; Xia, Tian; Lian, Yongfu

    2016-06-01

    Lithium iron phosphate (LiFePO4) has been evaluated as the most promising cathode material for the next generation lithium-ion batteries because of its high operating voltage, good cycle performance, low cost, and environmentally friendly safety. However, pure LiFePO4 shows poor reversible capacity and charge/discharge performance at high current density. Many methods including optimization of particle size, introduction of coating carbon and conductive polymer, and the doping of metal and halogen ions have been developed to improve its electrochemical performance. In this study, conductive polymer polyaniline (PANI), active carbon and LiFePO4 (C-LFP/PANI) composite cathodes were successfully prepared by chemical oxidation method. Electrochemical performance shows that a remarkable improvement in capacity and rate performance can be achieved in the C-LFP/PANI composite cathodes with an addition of HCI. In comparison with C-LFP cathode, the C-LFP/PANI doped with HCl composite exhibits ca. 15% and 26% capacity enhancement at 0.2 C and 10 C, respectively. PMID:27427742

  4. A Ternary Polyaniline/Active Carbon/Lithium Iron Phosphate Composite as Cathode Material for Lithium Ion Battery.

    PubMed

    Wang, Xiaohong; Zhang, Wuxing; Huang, Yunhui; Xia, Tian; Lian, Yongfu

    2016-06-01

    Lithium iron phosphate (LiFePO4) has been evaluated as the most promising cathode material for the next generation lithium-ion batteries because of its high operating voltage, good cycle performance, low cost, and environmentally friendly safety. However, pure LiFePO4 shows poor reversible capacity and charge/discharge performance at high current density. Many methods including optimization of particle size, introduction of coating carbon and conductive polymer, and the doping of metal and halogen ions have been developed to improve its electrochemical performance. In this study, conductive polymer polyaniline (PANI), active carbon and LiFePO4 (C-LFP/PANI) composite cathodes were successfully prepared by chemical oxidation method. Electrochemical performance shows that a remarkable improvement in capacity and rate performance can be achieved in the C-LFP/PANI composite cathodes with an addition of HCI. In comparison with C-LFP cathode, the C-LFP/PANI doped with HCl composite exhibits ca. 15% and 26% capacity enhancement at 0.2 C and 10 C, respectively.

  5. The chemical exfoliation phenomena in layered GaSe-polyaniline composite.

    PubMed

    Aksimentyeva, Olena Igorivna; Demchenko, Pavlo Yuriyovich; Savchyn, Volodymyr Pavlovich; Balitskii, Olexiy Alexandrovich

    2013-01-01

    To elucidate the nature of polyaniline (PANI)-GaSe mutual interaction, we carried out structural studies of nano-GaSe powders encapsulated by PANI, exploiting X-ray diffraction and high resolution transmission electron microscopy (HRTEM). Mechanically and ultrasonically dispersed GaSe crystals were mixed with aniline, which then underwent polymerization. After such treatment, GaSe nanocrystals (as shown by HRTEM) consist of few elementary monolayer sandwiches of hexagonal GaSe structure along the crystallographic axis c with a mean diameter of 9.2 nm. There was a significant expansion of interplanar distances (up to 0.833 nm) for all of the nanocrystals observed compared to 0.796 nm for the single crystals.

  6. Calcined polyaniline-iron composite as a high efficient cathodic catalyst in microbial fuel cells.

    PubMed

    Lai, Bin; Wang, Peng; Li, Haoran; Du, Zhuwei; Wang, Lijuan; Bi, Sichao

    2013-03-01

    A new type of carbon-nitrogen-metal catalyst, PANI-Fe-C, was synthesized by calcination process. According to the results of FT-IR and XPS analysis, polyaniline chain was broken by calcination. Small nitrogen-contained molecular fragments were gasified during calcination process, while the remaining nitrogen atoms were enchased in the new produced multiple carbon rings by C-N and CN bonds and performed as the catalytic active sites and the covalent centers for soluble iron components. Calculated from the polarization curves, a maximum power density of 10.17W/m(3) for the MFC with the synthetic catalyst was obtained, which was slightly higher than the MFC with Pt/C catalyst of 9.56W/m(3). All the results obtained in this paper proved that the newly synthetic nitrogen-carbon-metal catalyst would be a potential alternative to the expensive Pt/C catalyst in the field of MFC.

  7. Photoluminescence and Raman spectroscopy studies on polyaniline/PbI{sub 2} composite

    SciTech Connect

    Baibarac, M.; Baltog, I.; Lefrant, S.

    2009-04-15

    Functionalization of PbI{sub 2} with conjugated polymers (polyaniline-emeraldine base (PANI-EB) or polyaniline-emeraldine salt (PANI-ES)) is demonstrated by Raman and luminescence studies. PbI{sub 2}/PANI hybrid material was prepared by electrochemical polymerization of aniline onto the PbI{sub 2} modified Pt electrode and mechanico-chemical reaction between the two constituents. PANI interacting with the PbI{sub 2} gives rise to new Raman bands at 80, 144 and 170 cm{sup -1}. First line reveals the formation of 'stacking faults' that disrupt the I-Pb-I layers stacking along the c axis by the insertion of polymer molecules. The bands at 144 and 170 cm{sup -1} are attributed to the vibrational mode associated with Pb-NHR''{sub 2} (R''=C{sub 6}H{sub 4}) bond. The functionalization of PbI{sub 2} with PANI-EB brings forth the PANI-ES form. Depending on the semiconducting (PANI-EB) or conducting (PANI-ES) properties of the polymer in the PbI{sub 2}/PANI intercalated material, a partial or total collection of the charges generated under band to band irradiation is revealed by photoluminescence studies. - Graphical abstract: Experimental illustration of the extending along the c axis of a PbI{sub 2} single crystal by an intercalation process. In (a) is shown a crystal slide cleaved from a Bridgman-grown PbI{sub 2} crystal ingot and in (b) the same sample intercalated with pyridine obtained after an exposure for 24 h in a saturated atmosphere of pyridine.

  8. Novel Hybrid Materials with High Stability for Electrically Switched Ion Exchange: Carbon Nanotubes/Polyaniline/Nickel Hexacyanoferrate Nanocomposites

    SciTech Connect

    Lin, Yuehe; Cui, Xiaoli

    2005-04-21

    A novel and stable carbon nanotubes /polyaniline /nickel hexacyanoferrates composite film has been synthesized with electrodeposition method, and the possibility for removing cesium through an electrically switched ion exchange has been evaluated in a mixture containing NaNO3 and CsNO3.

  9. Structural and optical study of spin-coated camphorsulfonic acid-doped polyaniline/titanium-di-oxide nanoparticles hybrid thin films

    NASA Astrophysics Data System (ADS)

    Geethalakshmi, D.; Muthukumarasamy, N.; Balasundaraprabhu, R.

    2015-06-01

    Polyaniline (PANI) doped with Camphorsulfonic acid (CSA) has been prepared by chemical oxidative polymerization and blend with titanium-di-oxide (TiO2) nanoparticles prepared by sol-gel method to form CSA-doped PANI/TiO2 hybrid thin films. The properties of as-deposited and heat-treated (100 °C) hybrid thin films having different PANI:TiO2 weight ratios (1:0.5, 1:1, and 1:2) have been compared. FTIR study indicated that chemical bonding between CSA-doped PANI and TiO2 has been formed. XRD studies reveal that the as-deposited hybrid thin films are of amorphous nature and heat-treatment of such films initiates crystallization. SEM study shows that as-deposited hybrid films are rough; increase in TiO2 ratio and heat-treatment increased the roughness due to coalescing and agglomeration. UV-visible absorbance of hybrid films shows its characteristic peak in the visible region along with a peak in UV range and its intensity increased with TiO2 ratio and heat-treatment due to agglomeration of TiO2 particles. Photoluminescence spectra revealed that emission occurs in visible region (495 nm) for as-deposited hybrid thin film and this emission increased with TiO2 ratio and heat-treatment of hybrid films.

  10. Electronic conduction in polyaniline-polyethylene oxide and polyaniline-Nafion blends: Relation to morphology and protonation level

    SciTech Connect

    Sixou, B.; Travers, J.P.

    1997-08-01

    We present a comprehensive study of the transport properties in polyaniline-Nafion and polyaniline-polyethylene oxide, lithium trifluoromethane sulfonimide complex blends, together with a careful characterization of the morphology and the polyaniline protonation level. They include conductivity measurements as a function of both the polyaniline content of the blends and the temperature for a given composition. We show that percolation theory can account for the data provided that hopping and tunneling are taken into account. Moreover, in the polyaniline-Nafion blends, the variation of the polyaniline protonation level with the blend composition appears as a crucial parameter. The leading conduction mechanism is shown to be a hopping process between highly conducting polyaniline grains, the parameters of which are determined by the blend composition, and the protonation level. {copyright} {ital 1997} {ital The American Physical Society}

  11. An intimately bonded titanate nanotube-polyaniline-gold nanoparticle ternary composite as a scaffold for electrochemical enzyme biosensors.

    PubMed

    Liu, Xiaoqiang; Zhu, Jie; Huo, Xiaohe; Yan, Rui; Wong, Danny K Y

    2016-03-10

    In this work, titanate nanotubes (TNTs), polyaniline (PANI) and gold nanoparticles (GNPs) were assembled to form a ternary composite, which was then applied on an electrode as a scaffold of an electrochemical enzyme biosensor. The scaffold was constructed by oxidatively polymerising aniline to produce an emeraldine salt of PANI on TNTs, followed by gold nanoparticle deposition. A novel aspect of this scaffold lies in the use of the emeraldine salt of PANI as a molecular wire between TNTs and GNPs. Using horseradish peroxidase (HRP) as a model enzyme, voltammetric results demonstrated that direct electron transfer of HRP was achieved at both TNT-PANI and TNT-PANI-GNP-modified electrodes. More significantly, the catalytic reduction current of H2O2 by HRP was ∼75% enhanced at the TNT-PANI-GNP-modified electrode, compared to that at the TNT-PANI-modified electrode. The heterogeneous electron transfer rate constant of HRP was found to be ∼3 times larger at the TNT-PANI-GNP-modified electrode than that at the TNT-PANI-modified electrode. Based on chronoamperometric detection of H2O2, a linear range from 1 to 1200 μM, a sensitivity of 22.7 μA mM(-1) and a detection limit of 0.13 μM were obtained at the TNT-PANI-GNP-modified electrode. The performance of the biosensor can be ascribed to the superior synergistic properties of the ternary composite.

  12. Water-processable laponite/polyaniline/graphene oxide nanocomposites for energy applications.

    PubMed

    Ramphal, Isaac A; Hagerman, Michael E

    2015-02-01

    Graphene-polyaniline (GP) nanocomposites have demonstrated remarkable ability as supercapacitive materials and are typically synthesized via chemical reduction of graphene oxide/polyaniline (GOP) precursors. We report the formation of novel nanomaterials combining GOP nanocomposites with Laponite nanodisks. Host-guest interactions within GOP systems were studied with and without Laponite nanoparticle templating agents. Incorporating Laponite clay into the composite synthesis enhances aqueous dispersibility as well as facilitates the casting of homogeneous films. Structural and morphological characterization confirmed porous heterointerfaces and control of polymer and nanoclay loading. These results may enable the development of flexible supercapacitive and solar nanocomposites with improved device utility, water dispersibility, and film processability. We demonstrate that these films can be easily cast and that the composites maintain their electrical transport properties. PMID:25569226

  13. Synergy between polyaniline and OMt clay mineral in Langmuir-Blodgett films for the simultaneous detection of traces of metal ions.

    PubMed

    de Barros, Anerise; Ferreira, Mariselma; Constantino, Carlos José Leopoldo; Bortoleto, José Roberto Ribeiro; Ferreira, Marystela

    2015-04-01

    We report on Langmuir-Blodgett (LB) films made with emeraldine salt polyaniline (PAni-ES) and organophilic montmorillonite clay mineral (OMt), where synergy between the components was reached to yield an enhanced performance in detecting trace levels of cadmium (Cd(2+)), lead (Pb(2+)) and copper (Cu(2+)). Detection was carried out using square wave anodic stripping (SWAS) voltammetry with indium tin oxide (ITO) electrodes modified with LB films of PAni-ES/OMt nanocomposite, whose data were compared to those obtained with electrodes coated with neat PAni-ES and neat OMt LB films. The enhanced performance in the nanocomposite may be attributed to the stabilizing and ordering effect promoted by OMt in PAni-ES Langmuir films, which then led to more homogeneous LB films. According to X-ray diffraction data, the stacking of OMt layers was preserved in the LB films and therefore the PAni-ES chains did not cause clay mineral exfoliation. Instead, OMt affected the polaronic state of PAni-ES as indicated in UV-vis, Raman and FTIR spectra, also consistent with the changes observed for the Langmuir films. Taken together these results do indicate that semiconducting polymers and clay minerals may be combined for enhancing the electrical properties of nanostructures for sensing and related applications.

  14. Simultaneously improving electrical conductivity and thermopower of polyaniline composites by utilizing carbon nanotubes as high mobility conduits.

    PubMed

    Wang, Hong; Yi, Su-in; Pu, Xiong; Yu, Choongho

    2015-05-13

    Electrical conductivity and thermopower of isotropic materials typically have inversely proportional correlation because both are strongly affected in the opposite way by the electronic carrier concentration. This behavior has been one of the major hurdles in developing high-performance thermoelectrics whose figure-of-merit enhances with large thermopower and high electrical conductivity. Here we report a promising method of simultaneously improving both properties with polyaniline (PANI) composites filled by carbon nanotubes (CNTs). With addition of double-wall CNTs (DWCNTs), the electronic mobility of PANI doped with camphorsulfonic acid (PANI-CSA) was raised from ∼0.15 to ∼7.3 cm(2)/(V s) (∼50 time improvement) while the carrier concentration was decreased from ∼2.1 × 10(21) to ∼5.6 × 10(20) cm(-3) (∼4 time reduction). The larger increase of mobility increased electrical conductivity despite the carrier concentration reduction that enlarges thermopower. The improvement in the carrier mobility could be attributed to the band alignment that attracts hole carriers to CNTs whose mobility is much higher than that of PANI-CSA. The electrical conductivity of the PANI-CSA composites with 30-wt % DWCNTs was measured to be ∼610 S/cm with a thermopower value of ∼61 μV/K at room temperature, resulting in a power factor value of ∼220 μW/(m K(2)), which is more than two orders higher than that of PANI-CSA as well as the highest among those of the previously reported PANI composites. Further study may result in high performance thermoelectric organic composites uniquely offering mechanical flexibility, light weight, low toxicity, and easy manufacturing. unlike conventional inorganic semiconductors.

  15. Development of glucose biosensors based on nanostructured graphene-conducting polyaniline composite.

    PubMed

    Feng, Xue; Cheng, Huijun; Pan, Yiwen; Zheng, Hao

    2015-08-15

    A biosensor was fabricated by immobilizing glucose oxidase (GOD) into nanostructured graphene (GRA)-conducting polyaniline (PANI) nanocomposite, which was based on electrochemical polymerization of aniline in GRA synthesized by using electrochemical expansion of graphite in propylene carbonate electrolyte. Scanning electron spectroscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the morphology and performance of the as-prepared biosensor, respectively. Amperometric measurements were carried out to optimize test conditions (pH and applied potential) of the biosensor. Under the optimal conditions, the biosensor showed a linear range from 10.0 μM to 1.48 mM (R(2)=0.9988) with a sensitivity of 22.1 μA mM(-1) cm(-2), and a detection limit of 2.769 μM (S/N=3). The apparent Michaelis-Menten constant (KM(a)) was estimated to be 3.26 mM. The interference from glycine (Gly), D-galactose (D-Gal), urea (Urea), L-phenylalanine (L-Phe), ascorbic acid (AA), and L-tyrosine (L-Tyr) was also investigated. The results indicated that the biosensor exhibit high sensitivity and superior selectivity, providing a hopeful candidate for glucose biosensing. PMID:25845333

  16. Development of glucose biosensors based on nanostructured graphene-conducting polyaniline composite.

    PubMed

    Feng, Xue; Cheng, Huijun; Pan, Yiwen; Zheng, Hao

    2015-08-15

    A biosensor was fabricated by immobilizing glucose oxidase (GOD) into nanostructured graphene (GRA)-conducting polyaniline (PANI) nanocomposite, which was based on electrochemical polymerization of aniline in GRA synthesized by using electrochemical expansion of graphite in propylene carbonate electrolyte. Scanning electron spectroscopy (SEM), cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the morphology and performance of the as-prepared biosensor, respectively. Amperometric measurements were carried out to optimize test conditions (pH and applied potential) of the biosensor. Under the optimal conditions, the biosensor showed a linear range from 10.0 μM to 1.48 mM (R(2)=0.9988) with a sensitivity of 22.1 μA mM(-1) cm(-2), and a detection limit of 2.769 μM (S/N=3). The apparent Michaelis-Menten constant (KM(a)) was estimated to be 3.26 mM. The interference from glycine (Gly), D-galactose (D-Gal), urea (Urea), L-phenylalanine (L-Phe), ascorbic acid (AA), and L-tyrosine (L-Tyr) was also investigated. The results indicated that the biosensor exhibit high sensitivity and superior selectivity, providing a hopeful candidate for glucose biosensing.

  17. Inhibitive detection of benzoic acid using a novel phenols biosensor based on polyaniline-polyacrylonitrile composite matrix.

    PubMed

    Shan, Dan; Shi, Qiaofang; Zhu, Daobin; Xue, Huaiguo

    2007-07-31

    A novel sensitive and stable phenols amperometric biosensor, based on polyaniline-polyacrylonitrile composite matrix, was applied for determination of benzoic acid. The electrochemical biosensor functioning was based on the inhibition effect of benzoic acid on the biocatalytic activity of the polyphenol oxidase (PPO) to its substrate (catechol) in 0.1M phosphate buffer solution (pH 6.5). A potential value of -50 mV versus SCE, and a constant catechol concentration of 20 microM were selective to carry out the amperometric inhibition measurement. The kinetic parameters Michaelis-Menten constant (K(M)(app)) and maximum current (I(max)) in the absence and in the presence of benzoic acid were also evaluated and the possible inhibition mechanism was deduced. The inhibiting action of benzoic acid on the polyphenol oxidase electrode was reversible and of the typical competitive type, with an apparent inhibition constant of 38 microM. This proposed biosensor detected levels of benzoic acid as low as 2x10(-7)M in solution. In addition, the effects of temperature, pH value of solution on the inhibition and the interferences were investigated and discussed herein. Inhibition studies revealed that the proposed electrochemical biosensor was applicable for monitoring benzoic acid in real sample such as milk, yoghurt, sprite and cola. PMID:19071830

  18. Creatinine and urea biosensors based on a novel ammonium ion-selective copper-polyaniline nano-composite.

    PubMed

    Zhybak, M; Beni, V; Vagin, M Y; Dempsey, E; Turner, A P F; Korpan, Y

    2016-03-15

    The use of a novel ammonium ion-specific copper-polyaniline nano-composite as transducer for hydrolase-based biosensors is proposed. In this work, a combination of creatinine deaminase and urease has been chosen as a model system to demonstrate the construction of urea and creatinine biosensors to illustrate the principle. Immobilisation of enzymes was shown to be a crucial step in the development of the biosensors; the use of glycerol and lactitol as stabilisers resulted in a significant improvement, especially in the case of the creatinine, of the operational stability of the biosensors (from few hours to at least 3 days). The developed biosensors exhibited high selectivity towards creatinine and urea. The sensitivity was found to be 85 ± 3.4 mAM(-1)cm(-2) for the creatinine biosensor and 112 ± 3.36 mAM(-1)cm(-2) for the urea biosensor, with apparent Michaelis-Menten constants (KM,app), obtained from the creatinine and urea calibration curves, of 0.163 mM for creatinine deaminase and 0.139 mM for urease, respectively. The biosensors responded linearly over the concentration range 1-125 µM, with a limit of detection of 0.5 µM and a response time of 15s. The performance of the biosensors in a real sample matrix, serum, was evaluated and a good correlation with standard spectrophotometric clinical laboratory techniques was found.

  19. Enhanced electrochemical performance of a crosslinked polyaniline-coated graphene oxide-sulfur composite for rechargeable lithium-sulfur batteries

    NASA Astrophysics Data System (ADS)

    Moon, San; Jung, Young Hwa; Kim, Do Kyung

    2015-10-01

    Due to the extraordinarily high theoretical capacity of sulfur (1675 mAh g-1), the lithium-sulfur (Li-S) battery has been considered a promising candidate for future high-energy battery applications. Li-S batteries, however, have suffered from limited cycle lives, mainly due to the formation of soluble polysulfides, which prevent the practical application of this attractive technology. The encapsulation of sulfur with various conductive materials has addressed this issue to some extent. Nevertheless, most approaches still present partial encapsulation of sulfur and moreover require a large quantity of conductive material (typically, >30 wt%), making the use of sulfur less desirable from the viewpoint of capacity. Here, we address these chronic issues of Li-S cells by developing a graphene oxide-sulfur composite with a thin crosslinked polyaniline (PANI) layer. Graphene oxide nanosheets with large surface area, high conductivity and a uniform conductive PANI layer, which are synthesized by a layer-by-layer method, have a synergetic interaction with a large portion of the sulfur in the active material. Furthermore, a simple crosslinking process efficiently prevents polysulfide dissolution, resulting in unprecedented electrochemical performance, even with a high sulfur content (∼75%): a high capacity retention of ∼80% is observed, in addition to 97.53% of the average Coulombic efficiency being retained after 500 cycles. The performance we demonstrate represents an advance in the field of lithium-sulfur batteries for applications such as power tools.

  20. Enhanced graphitization of carbon around carbon nanotubes during the formation of carbon nanotube/graphite composites by pyrolysis of carbon nanotube/polyaniline composites.

    PubMed

    Nam, Dong Hoon; Cha, Seung Il; Jeong, Yong Jin; Hong, Soon Hyung

    2013-11-01

    The carbon nanotubes (CNTs) are actively applied to the reinforcements for composite materials during last decade. One of the attempts is development of CNT/Carbon composites. Although there are some reports on the enhancement of mechanical properties by addition of CNTs in carbon or carbon fiber, it is far below the expectation. Considering the microstructure of carbon materials such as carbon fiber, the properties of them can be modified and enhanced by control of graphitization and alignment of graphene planes. In this study, enhanced graphitization of carbon has been observed the vicinity of CNTs during the pyrolysis of CNT/Polyaniline composites. As a result, novel types of composite, consisting of treading CNTs and coated graphite, can be fabricated. High-resolution transmission electron microscopy revealed a specific orientation relationship between the graphene layers and the CNTs, with an angle of 110 degrees between the layers and the CNT axis. The possibility of graphene alignment control in the carbon by the addition of CNTs is demonstrated.

  1. Synthesis and properties of a newly obtained sorbent based on silica gel coated with a polyaniline film as the stationary phase for non-suppressed ion chromatography.

    PubMed

    Sowa, Ireneusz; Wójciak-Kosior, Magdalena; Drączkowski, Piotr; Strzemski, Maciej; Kocjan, Ryszard

    2013-07-17

    The new sorbent for non-suppressed ion chromatography based on silica gel coated with a film of polyaniline (PANI) was obtained in a process of in situ polymerization of aniline by oxidation with ammonium peroxydisulfate. Raman analyses performed using a Thermo Scientific DXR confocal Raman Microscope equipped with the Omnic 8 software from Thermo Fisher Scientific have proved a uniform distribution of PANI on the surface of chromatographic beads and in the pores of the particle. The obtained stationary phase was packed into a stainless steel HPLC column. The quality of the prepared column was verified on the basis of hydrodynamic parameters such as column efficiency index (Ip) and separation impedance (E). The potential application of silica gel modified with polyaniline for separation and determination of selected anions using non-suppressed ion chromatography was also investigated. Chromatographic analyses were performed using of the ion chromatograph Dionex DX-500. The best results were obtained for the mobile phase consisting of an aqueous or methanolic solution of hydrochloric acid. The tested column and optimized chromatographic system were successfully used for the analysis of nitrate, bromide and iodide in waters samples.

  2. Thin and flexible all-solid supercapacitor prepared from novel single wall carbon nanotubes/polyaniline thin films obtained in liquid-liquid interfaces

    NASA Astrophysics Data System (ADS)

    de Souza, Victor Hugo Rodrigues; Oliveira, Marcela Mohallem; Zarbin, Aldo José Gorgatti

    2014-08-01

    The present work describes for the first time the synthesis and characterization of single wall carbon nanotubes/polyaniline (SWNTs/PAni) nanocomposite thin films in a liquid-liquid interface, as well as the subsequent construction of a flexible all-solid supercapacitor. Different SWNTs/PAni nanocomposites were prepared by varying the ratio of SWNT to aniline, and the samples were characterized by scanning and transmission electron microscopy, Raman and UV-Vis spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The pseudo-capacitive behavior of the nanocomposites was evaluated by charge/discharge galvanostatic measurements. The presence of the SWNTs affected the electronic and vibrational properties of the polyaniline and also improved the pseudo-capacitive behavior of the conducting polymer. A very thin and flexible all-solid device was manufactured using two electrodes (polyethylene terephthalate-PET covered with the SWNT/PAni nanocomposite separated by a H2SO4-PVA gel electrolyte). The pseudo-capacitive behavior was characterized by a volumetric specific capacitance of approximately 76.7 F cm-3, even under mechanical deformation, indicating that this nanocomposite has considerable potential for application in new-generation energy storage devices.

  3. Biodegradable lignin/polyolefin composite films

    SciTech Connect

    Kosikova, B.; Demjanova, V.; Mikulasova, M.; Lora, J.H.

    1993-12-31

    From the view point of environmental protection, the plastic wastes, especially from packing materials, represent a potential waste problem. Various approaches were examined to develop partially or completely biodegradable plastics. New type of partially biodegradable polyolefins was prepared by blending of polypropylene with lignin, which was recovered in the ALCELL process, an organosolv pulping process that uses ethanol-water as the delignifying agent. Films of blends with up to 10% wt ALCELL lignin, prepared in absence of commercial stabilizers, had acceptable mechanical strengths. The effect of lignin on biodegradability of the composite films was examined by comparison of behaviour of both pure and lignin containing films during treatment with fungus Phanerochaete chrysosporium. It was found that this fungus is able to grow and to produce lignolytic enzymes in the presence of the films containing lignin. Biodegradation of lignin in the composite film was confirmed by the releasing of lignin fragments into the extracellular fluid. Because of measurement of mechanical properties offers a mean of direct estimation of polymer degradation, the degree of biodegradation of the films tested was followed by monitoring of elongation at break. The changes of break at elongation in the course of enzymatic treatment revealed that the lignin/PP composite films are potentially environmentally nonpersisting. The micrographs of the lignin containing films obtained by scanning electron microscopy show the significant changes of the film surface upon degradation with Phanerochaete chrysosporium in contrast to unchanged lignin free film.

  4. DC Electrical Conductivity Retention, Optical Properties and Ammonia Sensing Analysis of Naturally Degraded CSA-Doped Graphene/polyaniline Composite Nanofibers Prepared with CTAB

    NASA Astrophysics Data System (ADS)

    Ghazali, Sayyed; Hossain, Muhammad M.; Khan, Abuzar; Khan, Mohd Y.; Hasan, Mudassir

    2016-09-01

    In this paper, we report surfactant-mediated synthesis of camphor sulfonic acid (CSA)-doped polyaniline/graphene (PANI/GN) composite nanofibers as an electrical conductor and excellent ammonia sensor. The synthesis was mediated by cetyltrimethylammonium bromide as surfactant. The as-synthesized composite nanofibers were characterized by Raman spectroscopy, scanning electron microscopy, tunneling electron microscopy, x-ray diffraction, diffused reflectance spectroscopy and differential scanning calorimetry. The electrical conductivity of the CSA-doped PANI/GN composite nanofibers was found to be remarkably enhanced as compared to the CSA-doped PANI. The boost in electronic conductivity could be attributed to an improved electronic interaction between CSA-doped PANI backbone and GN present in the composite system. The naturally degraded CSA-doped PANI/GN composite nanofibers showed a decrease in electrical conductivity but worked as a good ammonia sensor in open atmospheric conditions.

  5. Effects of acidity on the size of polyaniline-poly(sodium 4-styrenesulfonate) composite particles and the stability of corresponding colloids in water.

    PubMed

    Li, Ligui; Ferng, Linhui; Wei, Yen; Yang, Catherine; Ji, Hai-Feng

    2012-09-01

    The practical application of polyaniline-poly(sodium 4-styrenesulfonate) (PANI-PSS) composite particles has been held back by the low stability of their dispersed state in water. In this work, we present a general oxidation approach to prepare PANI-PSS composite nanoparticles that can form highly stable colloids in water or buffer over a wide range of pH from 1 to 11. We demonstrate that the size of the PANI-PSS composite particles can be controlled by the acidity of precursor solutions. It is hypothesized that the number of negatively charged sites on PSS, which can be affected by the acidity of the precursor solutions, plays an important role in determining the size of the PANI-PSS composite particles and the stability of corresponding colloids in water. PMID:22647343

  6. Effects of acidity on the size of polyaniline-poly(sodium 4-styrenesulfonate) composite particles and the stability of corresponding colloids in water.

    PubMed

    Li, Ligui; Ferng, Linhui; Wei, Yen; Yang, Catherine; Ji, Hai-Feng

    2012-09-01

    The practical application of polyaniline-poly(sodium 4-styrenesulfonate) (PANI-PSS) composite particles has been held back by the low stability of their dispersed state in water. In this work, we present a general oxidation approach to prepare PANI-PSS composite nanoparticles that can form highly stable colloids in water or buffer over a wide range of pH from 1 to 11. We demonstrate that the size of the PANI-PSS composite particles can be controlled by the acidity of precursor solutions. It is hypothesized that the number of negatively charged sites on PSS, which can be affected by the acidity of the precursor solutions, plays an important role in determining the size of the PANI-PSS composite particles and the stability of corresponding colloids in water.

  7. Polyaniline/Carbon Nitride Nanosheets Composite Hydrogel: A Separation-Free and High-Efficient Photocatalyst with 3D Hierarchical Structure.

    PubMed

    Jiang, Wenjun; Luo, Wenjiao; Zong, Ruilong; Yao, Wenqing; Li, Zhanping; Zhu, Yongfa

    2016-08-01

    A polyaniline (PANI)/carbon nitride nanosheets (CNNS) composite hydrogel with 3D hierarchical nanostructure is synthesized via in situ polymerization. The 3D hierarchical structure is robust and stable, making the composite hydrogel separation-free and easy to recycling. It is highly excellent in removing organic pollutant for PANI/CNNS composite hydrogel on account of the cooperation of adsorptive preconcentration and the following photocatalytic oxidation. Pollutants are first adsorbed and concentrated into the 3D hierarchical nanostructure of the composite hydrogel. Then the pollutants are in situ oxidized via photocatalysis. The promoted photocatalytic performance can be mainly ascribed to the outstanding interfacial charge separation and photoelectrochemical performance. A new idea of the construction of 3D hierarchical photocatalysts is presented, which can be applied in the sustainability field.

  8. Effect of nanostructured graphene oxide on electrochemical activity of its composite with polyaniline titanium dioxide

    NASA Astrophysics Data System (ADS)

    Binh Phan, Thi; Thanh Luong, Thi; Mai, Thi Xuan; Thanh Thuy Mai, Thi; Tot Pham, Thi

    2016-03-01

    Graphene oxide (GO) significantly affects the electrochemical activity of its composite with polyanline titanium dioxide (TiO2). In this work various composites with different GO contents have been successfully synthesized by chemical method to compare not only their material properties but also electrochemical characteristics with each other. The results of an electrochemical impedance study showed that their electrochemical property has been improved due to the presence of GO in a composite matrix. The galvanodynamic polarization explained that among them the composite with GO/Ani ratio in the range of 1-14 exhibits a better performance compared to the other due to yielding a higher current desity (280 μA cm-2). The TEM and SEM images which presented the fibres of a composite bundle with the presence of PANi and TiO2 were examined by IR-spectra and x-ray diffraction, respectively.

  9. Thin film dielectric composite materials

    DOEpatents

    Jia, Quanxi; Gibbons, Brady J.; Findikoglu, Alp T.; Park, Bae Ho

    2002-01-01

    A dielectric composite material comprising at least two crystal phases of different components with TiO.sub.2 as a first component and a material selected from the group consisting of Ba.sub.1-x Sr.sub.x TiO.sub.3 where x is from 0.3 to 0.7, Pb.sub.1-x Ca.sub.x TiO.sub.3 where x is from 0.4 to 0.7, Sr.sub.1-x Pb.sub.x TiO.sub.3 where x is from 0.2 to 0.4, Ba.sub.1-x Cd.sub.x TiO.sub.3 where x is from 0.02 to 0.1, BaTi.sub.1-x Zr.sub.x O.sub.3 where x is from 0.2 to 0.3, BaTi.sub.1-x Sn.sub.x O.sub.3 where x is from 0.15 to 0.3, BaTi.sub.1-x Hf.sub.x O.sub.3 where x is from 0.24 to 0.3, Pb.sub.1-1.3x La.sub.x TiO.sub.3+0.2x where x is from 0.23 to 0.3, (BaTiO.sub.3).sub.x (PbFeo.sub.0.5 Nb.sub.0.5 O.sub.3).sub.1-x where x is from 0.75 to 0.9, (PbTiO.sub.3).sub.- (PbCo.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.1 to 0.45, (PbTiO.sub.3).sub.x (PbMg.sub.0.5 W.sub.0.5 O.sub.3).sub.1-x where x is from 0.2 to 0.4, and (PbTiO.sub.3).sub.x (PbFe.sub.0.5 Ta.sub.0.5 O.sub.3).sub.1-x where x is from 0 to 0.2, as the second component is described. The dielectric composite material can be formed as a thin film upon suitable substrates.

  10. Magnetoelectric thin film composites with interdigital electrodes

    NASA Astrophysics Data System (ADS)

    Piorra, A.; Jahns, R.; Teliban, I.; Gugat, J. L.; Gerken, M.; Knöchel, R.; Quandt, E.

    2013-07-01

    Magnetoelectric (ME) thin film composites on silicon cantilevers are fabricated using Pb(Zr0.52Ti0.45)O3 (PZT) films with interdigital transducer electrodes on the top side and FeCoSiB amorphous magnetostrictive thin films on the backside. These composites without any direct interface between the piezoelectric and magnetostrictive phase are superior to conventional plate capacitor-type thin film ME composites. A limit of detection of 2.6 pT/Hz1/2 at the mechanical resonance is determined which corresponds to an improvement of a factor of approximately 2.8 compared to the best plate type sensor using AlN as the piezoelectric phase and even a factor of approximately 4 for a PZT plate capacitor.

  11. Electrochemical Tailoring of Fibrous Polyaniline and Electroless Decoration with Gold and Platinum Nanoparticles.

    PubMed

    Abdelhamid, Muhammad E; Snook, Graeme A; O'Mullane, Anthony P

    2016-09-01

    Presented in this work is a facile and quick electrochemical method for controlling the morphology of thick polyaniline (PANi) films, without the use of templates. By stepping the polymerization potential from high voltages to a lower (or series of lower) voltage(s), we successfully controlled the morphology of the polymer, and fibrous structures, unique to each potential step, were achieved. In addition, the resultant film was tested electrochemically for its viability as an electrode material for flexible batteries and supercapacitors. Furthermore, the PANi film was decorated with gold and platinum nanoparticles via an electroless deposition process for possible electrocatalytic applications, whereby the oxidation of hydrazine at the composite was investigated. PMID:27531044

  12. Graphene/heparin template-controlled polyaniline nanofibers composite for high energy density supercapacitor electrode

    NASA Astrophysics Data System (ADS)

    Moniruzzaman Sk, Md; Yue, Chee Yoon; Jena, Rajeeb Kumar

    2014-12-01

    Graphene/PANI nanofibers composites are prepared for the first time using a novel in situ polymerization method based on the chemical oxidative polymerization of aniline using heparin as a soft template. The even dispersion of individual graphene sheet within the polymer nanofibers matrix enhances the kinetics for both charge transfer and ion transport throughout the electrode. This novel G25PNF75 composite (weight ratio of GO:PANI = 25:75) shows a high specific capacitance of 890.79 F g-1 and an excellent energy density of 123.81 Wh kg-1 at a constant discharge current of 0.5 mA. The composite exhibits excellent cycle life with 88.78% specific capacitance retention after 1000 charge-discharge cycles. The excellent performance of the composite is due to the synergistic combination of graphene which provides good electrical conductivity and mechanical stability, and PANI nanofiber which provides good redox activity that consequently contributed such high energy density.

  13. Synthesis of nanostructured polyaniline

    NASA Astrophysics Data System (ADS)

    Surwade, Sumedh P.

    The organization of my thesis is as follows: (a) Chapter III describes the synthesis of bulk quantities of polyaniline nanofibers in one step using a simple and versatile high ionic strength aqueous system (HCl/NaCl) that permits the use of pure H2O2 as a mild oxidant without any added metal or enzyme catalyst. Polyaniline nanofibers obtained are highly conducting, sigma˜1--5 S/cm, and spectroscopically similar to conventional polyaniline synthesized using stronger oxidants. The synthesis method is further extended to the synthesis of oligoanilines of controlled molecular weight, e.g., aniline tetramer, octamer, and hexadecamer. Microns long tetramer nanofibers are synthesized using this method. (b) Chapter IV describes the mechanism of nanofiber formation in polyaniline. It is proposed that the surfaces such as the walls of the reaction vessel and/or intentionally added surfaces play a dramatic role in the evolution of nanofibrillar morphology. Nucleation sites on surfaces promote the accumulation of aniline dimer that reacts further to yield aniline tetramer, which (surprisingly) is entirely in form of nanofibers and whose morphology is transcribed to the bulk by a double heterogeneous nucleation mechanism. This unexpected phenomenon could form the basis of nanofiber formation in all classes of precipitation polymerization systems. (c) Chapter V is the mechanistic study on the formation of oligoanilines during the chemical oxidation of aniline in weakly acidic, neutral or basic media using peroxydisulfate oxidant. It is proposed that the reaction proceeds via the intermediacy of benzoquinone monoimine that is formed as a result of a Boyland-Sims rearrangement of aniline. The initial role of peroxydisulfate is to provide a pathway for the formation of benzoquinone monoimine intermediate that is followed by a conjugate Michael-type addition reaction with aniline or sulfated anilines. The products isolated in pH 2.5--10.0 buffers are intermediate species at various

  14. Preparation and Properties of Fibrous Fe3O4/Polyaniline Nanocomposites.

    PubMed

    Wang, Li; Zhang, Xin

    2015-04-01

    By using inorganic Fe3O4 nanoparticles as nucleation sites, Fe3O4/polyaniline magnetic nanocomposites are successfully synthesized by chemical oxidative polymerization method. The morphology and properties of Fe3O4/polyaniline nanocomposites are characterized by XRD, FTIR, TEM, DSC, TG and VSM. XRD, FTIR and DSC jointly indicate that the composites comprise Fe3O4 and polyaniline. TEM micrographs indicate that the Fe3O4 magnetic nanoparticles have an average diameter less than 20 nm and achieve better property of dispersion after composited with polyaniline. With the content of polyaniline increasing, Fe3O4/polyaniline composites change from aggregated particles to fibers. Fibrous composites achieve excellent thermal stability and attractive polyaniline content dependence of magnetism. TG analyses reveal that apparent weight loss of the fibrous composite appears at higher temperature than the granular Fe3O4/polyaniline composite does. With the increasing of the content of polyaniline, the magnetism of Fe3O4/polyaniline composite change from ferromagnetism to paramagnetism, while the magnetization decreases firstly and then increases. The formation of fibrous Fe3O4/polyaniline composite is favorable for the magnetization.

  15. Polyaniline-iron oxide nanohybrid film as multi-functional label-free electrochemical and biomagnetic sensor for catechol.

    PubMed

    Chandra, Sudeshna; Lang, Heinrich; Bahadur, Dhirendra

    2013-09-17

    Polyaniline-iron oxide magnetic nanohybrid was synthesized and characterized using various spectroscopic, microstructural and electrochemical techniques. The smart integration of Fe3O4 nanoparticles within the polyaniline (PANI) matrix yielded a mesoporous nanohybrid (Fe3O4@PANI) with high surface area (94 m(2) g(-1)) and average pore width of 12.8 nm. Catechol is quasi-reversibly oxidized to o-quinone and reduced at the Fe3O4@PANI modified electrodes. The amperometric current response toward catechol was evaluated using the nanohybrid and the sensitivity and detection limit were found to be 312 μA μL(-1) and 0.2 nM, respectively. The results from electrochemical impedance spectroscopy (EIS) indicated that the increased solution resistance (Rs) was due to elevated adsorption of catechol on the modified electrodes. Photoluminescence spectra showed ligand-to-metal charge transfer (LMCT) between p-π orbitals of the phenolate oxygen in catechol and the d-σ* metal orbital of Fe3O4@PANI nanohybrid. Potential dependent spectroelectrochemical behavior of Fe3O4@PANI nanohybrid toward catechol was studied using UV/vis/NIR spectroscopy. The binding activity of the biomagnetic particles to catechol through Brownian relaxation was evident from AC susceptibility measurements. The proposed sensor was used for successful recovery of catechol in tap water samples.

  16. Sensing element for detection of polar organic vapours on the base of polyaniline-composite - Effect of substrate surface area

    NASA Astrophysics Data System (ADS)

    Olejnik, Robert; Gorakh Babar, Dipak; Slobodian, Petr; Matyas, Jiri

    2016-03-01

    Conductive polymer polyaniline (PANI) was synthesized by oxidative polymerization of aniline hydrochloride as a source of aniline and ammonium persulfate as an oxidation agent. The polymerization process is relatively easy and cheap. The reaction was carried out in presence of polymer substrate, in our case polyethylene terephthalate (PET) as a representative of smooth surface substrate and polyvinylidenfluoride (PVDF) nanofibers membrane as a representative of porous substrate. Both these substrates were covered by polyaniline (PANI) and used as a sensing element for organic vapors detection. The detection was made by measuring and the record of the change of resistivity during adsorption and desorption of saturated vapors. The result shows that sensitivity decreases with increasing polarity of chosen solvent in order N,N- Dimethylformamide (DMF), N,N-Dimethylacetamide (DMAc) and Dimethyl sulfoxide (DMSO). The PANI base sensing element on PVDF substrate improves sensitivity, selectivity and it also has good reversibility and repeatability.

  17. Novel facile method for obtaining CdSe/polyaniline/C60 composite materials

    NASA Astrophysics Data System (ADS)

    Rusen, Edina; Diacon, Aurel; Mocanu, Alexandra; Nistor, Leona Cristina

    2016-08-01

    This study presents a novel method for the oxidative polymerization of aniline (ANI) by employing fullerene C60/cadmium selenide (CdSe) quantum dots, as promoting agent of the polymerization system. The polymerization initiation mechanism is based on the difference between the HOMO-LUMO energy levels of the components which permits the formation of a continuous donor-acceptor exchange. Both the polymerization reaction evolution and the molecular weights of the obtained polymers have been characterized. The novelty of the paper consists in the synthesis of a novel nano-composite material through a novel polymerization technique. The resulting material containing PANI, CdSe quantum dots and C60 has been characterized by UV-Vis, NIR, fluorescence, TEM and GPC analyses.

  18. Novel facile method for obtaining CdSe/polyaniline/C60 composite materials

    PubMed Central

    Rusen, Edina; Diacon, Aurel; Mocanu, Alexandra; Nistor, Leona Cristina

    2016-01-01

    This study presents a novel method for the oxidative polymerization of aniline (ANI) by employing fullerene C60/cadmium selenide (CdSe) quantum dots, as promoting agent of the polymerization system. The polymerization initiation mechanism is based on the difference between the HOMO-LUMO energy levels of the components which permits the formation of a continuous donor-acceptor exchange. Both the polymerization reaction evolution and the molecular weights of the obtained polymers have been characterized. The novelty of the paper consists in the synthesis of a novel nano-composite material through a novel polymerization technique. The resulting material containing PANI, CdSe quantum dots and C60 has been characterized by UV-Vis, NIR, fluorescence, TEM and GPC analyses. PMID:27572228

  19. Novel facile method for obtaining CdSe/polyaniline/C60 composite materials.

    PubMed

    Rusen, Edina; Diacon, Aurel; Mocanu, Alexandra; Nistor, Leona Cristina

    2016-01-01

    This study presents a novel method for the oxidative polymerization of aniline (ANI) by employing fullerene C60/cadmium selenide (CdSe) quantum dots, as promoting agent of the polymerization system. The polymerization initiation mechanism is based on the difference between the HOMO-LUMO energy levels of the components which permits the formation of a continuous donor-acceptor exchange. Both the polymerization reaction evolution and the molecular weights of the obtained polymers have been characterized. The novelty of the paper consists in the synthesis of a novel nano-composite material through a novel polymerization technique. The resulting material containing PANI, CdSe quantum dots and C60 has been characterized by UV-Vis, NIR, fluorescence, TEM and GPC analyses. PMID:27572228

  20. Aptameric Recognition-Modulated Electroactivity of Poly(4-Styrenesolfonic Acid)-Doped Polyaniline Films for Single-Shot Detection of Tetrodotoxin

    PubMed Central

    Fomo, Gertrude; Waryo, Tesfaye T.; Sunday, Christopher E.; Baleg, Abd A.; Baker, Priscilla G.; Iwuoha, Emmanuel I.

    2015-01-01

    The work being reported is the first electrochemical sensor for tetrodotoxin (TTX). It was developed on a glassy carbon electrodes (C) that was modified with poly(4-styrenesolfonic acid)-doped polyaniline film (PANI/PSSA). An amine-end functionalized TTX-binding aptamer, 5′-NH2-AAAAATTTCACACGGGTGCCTCGGCTGTCC-3′ (NH2-Apt), was grafted via covalent glutaraldehyde (glu) cross-linking. The resulting aptasensor (C//PANI+/PSSA-glu-NH2-Apt) was interrogated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in sodium acetate buffer (NaOAc, pH 4.8) before and after 30 min incubation in standard TTX solutions. Both CV and EIS results confirmed that the binding of the analyte to the immobilized aptamer modulated the electrochemical properties of the sensor: particularly the charge transfer resistance (Rct) of the PANI+/PSSA film, which served as a signal reporter. Based on the Rct calibration curve of the TTX aptasensor, the values of the dynamic linear range (DLR), sensitivity and limit of detection (LOD) of the sensor were determined to be 0.23–1.07 ng·mL−1 TTX, 134.88 ± 11.42 Ω·ng·mL−1 and 0.199 ng·mL−1, respectively. Further studies are being planned to improve the DLR as well as to evaluate selectivity and matrix effects in real samples. PMID:26370994

  1. Aptameric Recognition-Modulated Electroactivity of Poly(4-Styrenesolfonic Acid)-Doped Polyaniline Films for Single-Shot Detection of Tetrodotoxin.

    PubMed

    Fomo, Gertrude; Waryo, Tesfaye T; Sunday, Christopher E; Baleg, Abd A; Baker, Priscilla G; Iwuoha, Emmanuel I

    2015-09-08

    The work being reported is the first electrochemical sensor for tetrodotoxin (TTX). It was developed on a glassy carbon electrodes (C) that was modified with poly(4-styrenesolfonic acid)-doped polyaniline film (PANI/PSSA). An amine-end functionalized TTX-binding aptamer, 5'-NH₂-AAAAATTTCACACGGGTGCCTCGGCTGTCC-3' (NH₂-Apt), was grafted via covalent glutaraldehyde (glu) cross-linking. The resulting aptasensor (C//PANI⁺/PSSA-glu-NH2-Apt) was interrogated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) in sodium acetate buffer (NaOAc, pH 4.8) before and after 30 min incubation in standard TTX solutions. Both CV and EIS results confirmed that the binding of the analyte to the immobilized aptamer modulated the electrochemical properties of the sensor: particularly the charge transfer resistance (Rct) of the PANI⁺/PSSA film, which served as a signal reporter. Based on the Rct calibration curve of the TTX aptasensor, the values of the dynamic linear range (DLR), sensitivity and limit of detection (LOD) of the sensor were determined to be 0.23-1.07 ng·mL(-1) TTX, 134.88 ± 11.42 Ω·ng·mL(-1) and 0.199 ng·mL(-1), respectively. Further studies are being planned to improve the DLR as well as to evaluate selectivity and matrix effects in real samples.

  2. Further improvement of flame retardancy of polyaniline-deposited paper composite through using phytic acid as dopant or co-dopant.

    PubMed

    Zhou, Yang; Ding, Chunyue; Qian, Xueren; An, Xianhui

    2015-01-22

    Polyaniline (PANI)-deposited electrically conductive and flame retardant paper composite was prepared using phytic acid (PA) as dopant or co-dopant. PA as doping acid greatly improved the flame retardancy of PANI-deposited paper composite whilst the conductivity was lower compared with using 5-sulfosalicylic acid (SSA) as doping acid. Lower temperature was favorable to obtain PANI-deposited paper composite with both higher conductivity and better flame retardancy. Conductivity of PANI-deposited paper composite increased with increase of doping acid concentration and the suitable PA concentration range was 0.15-0.3 mol/L depending on the requirement of conductivity and flame retardancy. The PANI-deposited paper composite was characterized by SEM, TGA and XPS. The outstanding flame retardancy of PA-doped paper composite was caused by the synergetic effect of PANI coating and H3PO4. Both higher flame retardancy and higher conductivity of PANI-deposited paper composite were obtained by co-doping of SSA with PA.

  3. Thermal Conductivity of Carbon Nanotube Composite Films

    NASA Technical Reports Server (NTRS)

    Ngo, Quoc; Cruden, Brett A.; Cassell, Alan M.; Walker, Megan D.; Koehne, Jessica E.; Meyyappan, M.; Li, Jun; Yang, Cary Y.

    2004-01-01

    State-of-the-art ICs for microprocessors routinely dissipate power densities on the order of 50 W/sq cm. This large power is due to the localized heating of ICs operating at high frequencies, and must be managed for future high-frequency microelectronic applications. Our approach involves finding new and efficient thermally conductive materials. Exploiting carbon nanotube (CNT) films and composites for their superior axial thermal conductance properties has the potential for such an application requiring efficient heat transfer. In this work, we present thermal contact resistance measurement results for CNT and CNT-Cu composite films. It is shown that Cu-filled CNT arrays enhance thermal conductance when compared to as-grown CNT arrays. Furthermore, the CNT-Cu composite material provides a mechanically robust alternative to current IC packaging technology.

  4. Chitosan mediated synthesis of core/double shell ternary polyaniline/Chitosan/cobalt oxide nano composite-as high energy storage electrode material in supercapacitors

    NASA Astrophysics Data System (ADS)

    Vellakkat, Mini; Hundekkal, Devendrappa

    2016-01-01

    Nanostructured ternary composite of polyaniline (PANI), Co3O4 nanoparticles, and Chitosan (CS) has been prepared by an in situ chemical oxidation method, and the nanocomposites (CPAESCO) were used as supercapacitor electrodes. The Co3O4 nanoparticles are uniformly coated with CS and PANI layers in it. Different techniques (Fourier transform infrared spectrophotometry, x-ray diffraction, thermal gravimetric analysis, UV-visible spectroscopy, scanning electron microscopy, transmission electron microscopy and electro chemical analysis-cyclic voltammetry, galvanostatic charge/discharge (GCD), and electrochemical impedance spectroscopy) were used to analyse the optical, structural, thermal, chemical and supercapacitive aspects of the nanocomposites. Core/double shell ternary composite electrode exhibits significantly increased specific capacitance than PANI/Co3O4 or PANI/CS binary composites in supercapacitors. The ternary nanocomposite with 40% nanoparticle exhibits a highest specific capacitance reaching 687 F g-1, Energy density of (95.42 Wh kg-1 at 1 A g-1) and power density of (1549 W kg-1 at 3 A g-1) and outstanding cycling performance, with, 91% capacitance retained over 5000 cycles. It is found that this unique bio compatible nano composite with synergy is a new multifunctional material which will be useful in the design of supercapacitor electrodes and other energy conversion devices too.

  5. Excellent electromagnetic wave absorption property of quaternary composites consisting of reduced graphene oxide, polyaniline and FeNi3@SiO2 nanoparticles

    NASA Astrophysics Data System (ADS)

    Ding, Xiao; Huang, Ying; Wang, Jianguo; Wu, Haiwei; Liu, Panbo

    2015-12-01

    The electromagnetic wave absorption properties of the quaternary composites consisting of reduced graphene oxide (rGO), polyaniline (PANI), FeNi3@SiO2 (FeNi3 nanocrystals encapsulated in SiO2) nanoparticles had never been reported. In this case, we prepared FeNi3@SiO2@rGO-PANI quaternary composites and TEM results shows spherical nanoparticles are well distributed on the surface of rGO-PANI nanosheets. The investigation of the electromagnetic wave absorbability reveals that the quaternary composites exhibit wide absorption bandwidth and enhanced electromagnetic wave absorption properties. The absorption bandwidth with reflection loss less than -10 dB (90% attenuation) is up to 6.64 GHz (10.08-10.80 GHz, 12.08-18.0 GHz), and the maximum reflection loss reaches about -40.18 dB at 14.0 GHz with the thickness of 2.4 mm. It is believed that the FeNi3@SiO2@rGO-PANI composites can serve as excellent electromagnetic wave absorbent and can be widely used in practice.

  6. Direct measurement of colloidal interactions between polyaniline surfaces in a UV-curable coating formulation: the effect of surface hydrophilicity/hydrophobicity and resin composition.

    PubMed

    Jafarzadeh, Shadi; Claesson, Per M; Pan, Jinshan; Thormann, Esben

    2014-02-01

    The interactions between polyaniline particles and polyaniline surfaces in polyester acrylate resin mixed with 1,6-hexanediol diacrylate monomer have been investigated using contact angle measurements and the atomic force microscopy colloidal probe technique. Polyaniline with different characteristics (hydrophilic and hydrophobic) were synthesized directly on spherical polystyrene particles of 10 μm in diameter. Surface forces were measured between core/shell structured polystyrene/polyaniline particles (and a pure polystyrene particle as reference) mounted on an atomic force microscope cantilever and a pressed pellet of either hydrophilic or hydrophobic polyaniline powders, in resins of various polymer:monomer ratios. A short-range purely repulsive interaction was observed between hydrophilic polyaniline (doped with phosphoric acid) surfaces in polyester acrylate resin. In contrast, interactions between hydrophobic polyaniline (doped with n-decyl phosphonic acid) were dominated by attractive forces, suggesting less compatibility and higher tendency for aggregation of these particles in liquid polyester acrylate compared to hydrophilic polyaniline. Both observations are in agreement with the conclusions from the interfacial energy studies performed by contact angle measurements. PMID:24400981

  7. Plasmonic photosensitization of polyaniline prepared by a novel process for high-performance flexible photodetector.

    PubMed

    Barman, Tapan; Pal, Arup R

    2015-02-01

    We report the synthesis of a polyaniline (PAni)-gold nanoparticle (AuNP) composite thin film in a single step. A flexible high-performance visible photodetector is constructed using PAni-AuNP composite with low loading of AuNP, and optoelectronic properties of the device are evaluated. The present study demonstrates that a plasmonic hybrid nanocomposite prepared by a single-step novel plasma-based dry process could solve the low lifetime and performance-related issues of organic optoelectronic devices.

  8. Colloidal polyaniline

    DOEpatents

    Armes, Steven P.; Aldissi, Mahmoud

    1990-01-01

    Processable electrically conductive latex polymer compositions including colloidal particles of an oxidized, polymerized amino-substituted aromatic monomer, a stabilizing effective amount of a random copolymer containing amino-benzene type moieties as side chain constituents, and dopant anions, and a method of preparing such polymer compositions are provided.

  9. The Electropolymerization and Characterizations of Acid Red Dye Doped Polyaniline

    NASA Astrophysics Data System (ADS)

    Li, Xin; Liang, Fei-Yue; Liao, Jia-Xing; Wang, Rui; Zheng, Yi-Ping; Xian, Ze-Yu

    2016-05-01

    The electrochromic properties of an electrochemical polymerized composite consisted of polyaniline doped with acid red dye (PANI-ARD) are reported. The structures of PANIARD were characterized via cycle voltammograms, spectroelectrochemistry and colorimetric analysis. Film of the PANI-ARD composites of different concentrations appears violet, aubergine in the neutral state and darkblue in the oxidized state, which are different from the pure PANI of yellow (-0.8V) and blue (1.0V). The oxidation and reduction response speed of PANI-ARD was a bit lower than those obtained in pure PANI. It is shown that acid dye doping is an effective method to broaden the color change range of the electrochromicmateials.

  10. High-Performance Flexible Solid-State Carbon Cloth Supercapacitors Based on Highly Processible N-Graphene Doped Polyacrylic Acid/Polyaniline Composites

    NASA Astrophysics Data System (ADS)

    Wang, Yongguang; Tang, Shaochun; Vongehr, Sascha; Ali Syed, Junaid; Wang, Xiangyu; Meng, Xiangkang

    2016-02-01

    Improving the solubility of conductive polymers to facilitate processing usually decreases their conductivity, and they suffer from poor cycling stability due to swelling-shrinking during charging cycles. We circumvent these problems with a novel preparation method for nitrogen-doped graphene (NG) enhanced polyacrylic acid/polyaniline (NG-PAA/PANI) composites, ensuring excellent processibility for scalable production. The content of PANI is maximized under the constraint of still allowing defect-free coatings on filaments of carbon cloth (CC). The NG content is then adjusted to optimize specific capacitance. The optimal CC electrodes have 32 wt.% PANI and 1.3 wt.% NG, thus achieving a high capacitance of 521 F/g at 0.5 F/g. A symmetric supercapacitor made from 20 wt.% PANI CC electrodes has more than four times the capacitance (68 F/g at 1 A/g) of previously reported flexible capacitors based on PANI-carbon nanotube composites, and it retains the full capacitance under large bending angles. The capacitor exhibits high energy and power densities (5.8 Wh/kg at 1.1 kW/kg), a superior rate capability (still 81% of the 1 A/g capacitance at 10 A/g), and long-term electrochemical stability (83.2% retention after 2000 cycles).

  11. High-Performance Flexible Solid-State Carbon Cloth Supercapacitors Based on Highly Processible N-Graphene Doped Polyacrylic Acid/Polyaniline Composites

    PubMed Central

    Wang, Yongguang; Tang, Shaochun; Vongehr, Sascha; Ali Syed, Junaid; Wang, Xiangyu; Meng, Xiangkang

    2016-01-01

    Improving the solubility of conductive polymers to facilitate processing usually decreases their conductivity, and they suffer from poor cycling stability due to swelling-shrinking during charging cycles. We circumvent these problems with a novel preparation method for nitrogen-doped graphene (NG) enhanced polyacrylic acid/polyaniline (NG-PAA/PANI) composites, ensuring excellent processibility for scalable production. The content of PANI is maximized under the constraint of still allowing defect-free coatings on filaments of carbon cloth (CC). The NG content is then adjusted to optimize specific capacitance. The optimal CC electrodes have 32 wt.% PANI and 1.3 wt.% NG, thus achieving a high capacitance of 521 F/g at 0.5 F/g. A symmetric supercapacitor made from 20 wt.% PANI CC electrodes has more than four times the capacitance (68 F/g at 1 A/g) of previously reported flexible capacitors based on PANI-carbon nanotube composites, and it retains the full capacitance under large bending angles. The capacitor exhibits high energy and power densities (5.8 Wh/kg at 1.1 kW/kg), a superior rate capability (still 81% of the 1 A/g capacitance at 10 A/g), and long-term electrochemical stability (83.2% retention after 2000 cycles). PMID:26883179

  12. High-Performance Flexible Solid-State Carbon Cloth Supercapacitors Based on Highly Processible N-Graphene Doped Polyacrylic Acid/Polyaniline Composites.

    PubMed

    Wang, Yongguang; Tang, Shaochun; Vongehr, Sascha; Syed, Junaid Ali; Wang, Xiangyu; Meng, Xiangkang

    2016-02-17

    Improving the solubility of conductive polymers to facilitate processing usually decreases their conductivity, and they suffer from poor cycling stability due to swelling-shrinking during charging cycles. We circumvent these problems with a novel preparation method for nitrogen-doped graphene (NG) enhanced polyacrylic acid/polyaniline (NG-PAA/PANI) composites, ensuring excellent processibility for scalable production. The content of PANI is maximized under the constraint of still allowing defect-free coatings on filaments of carbon cloth (CC). The NG content is then adjusted to optimize specific capacitance. The optimal CC electrodes have 32 wt.% PANI and 1.3 wt.% NG, thus achieving a high capacitance of 521 F/g at 0.5 F/g. A symmetric supercapacitor made from 20 wt.% PANI CC electrodes has more than four times the capacitance (68 F/g at 1 A/g) of previously reported flexible capacitors based on PANI-carbon nanotube composites, and it retains the full capacitance under large bending angles. The capacitor exhibits high energy and power densities (5.8 Wh/kg at 1.1 kW/kg), a superior rate capability (still 81% of the 1 A/g capacitance at 10 A/g), and long-term electrochemical stability (83.2% retention after 2000 cycles).

  13. Synthesis and characterization of an electro-deposited polyaniline-bismuth telluride nanocomposite - A novel thermoelectric material

    SciTech Connect

    Chatterjee, Krishanu; Suresh, Asaithambi; Ganguly, Saibal; Kargupta, Kajari; Banerjee, Dipali

    2009-12-15

    The present work consists of synthesis and characterization of a novel thermoelectric material polyaniline (PANI)-bismuth telluride (Bi{sub 2}Te{sub 3}) nanocomposite using simultaneous electrochemical reactions and deposition method. The inorganic bismuth nitrate has been used as a dopant for polyaniline to achieve high electrical conductivity. A semi-batch mode of operation has been employed to control the rate of deposition of an individual component and thus the molecular architecture of the composite. The electro-deposited composite film on ITO coated glass substrate has been characterized by X-ray diffraction analysis (XRD), FTIR analysis, scanning electron microscope (SEM), and transmission electron microscope (TEM). The microscopic analysis reveals the formation of rod-like nanostructures of diameter less than 100 nm. It has been found that smaller molecules of Bi{sub 2}Te{sub 3} are dispersed in the macromolecules of PANI. The nanocomposite has been characterized by thermoelectric power.

  14. Stable, concentrated solutions of polyaniline using amines as gel inhibitors

    DOEpatents

    Wang, Hsing-Lin; Mattes, Benjamin R.

    2002-01-01

    Stable, concentrated solutions of high-molecular weight polyaniline using amines as gel inhibitors. Certain amine compounds (gel inhibitors) are used to form highly concentrated, stable solutions of the emeraldine base form of polyaniline in numerous organic solvents from which coatings, films and fibers are readily prepared without problems associated with rapid gelation which occurs when concentrated solutions are attempted without the use of the gel inhibitors of the present invention. Tertiary amines are used to solubilize low-molecular weight fractions (M.sub.w <120,000, M.sub.n <30,000) of the pernigraniline, emeraldine, and leucoemeraldine oxidation states of polyaniline as concentrated (>20 wt. %) polyaniline solutions, while primary and secondary amines are used to produce solutions having 15-40 wt % of high-molecular weight polyaniline [M.sub.w.gtoreq.120,000, M.sub.n.gtoreq.30,000]. Concentrated solutions of polyaniline co-polymers or ring and/or nitrogen-substituted polyanilines may also be prepared.

  15. One-step synthesis and characterization of polyaniline nanofiber/silver nanoparticle composite networks as antibacterial agents.

    PubMed

    Poyraz, Selcuk; Cerkez, Idris; Huang, Tung Shi; Liu, Zhen; Kang, Litao; Luo, Jujie; Zhang, Xinyu

    2014-11-26

    Through a facile and effective seeding polymerization reaction via a one-step redox/complexation process, which took place in aqueous medium at ambient temperature, silver nanoparticles (Ag NPs) embedded polyaniline nanofiber (PANI NF) networks were synthesized as antibacterial agents. During the reaction, not only NF morphology formation of the resulting conducting polymers (CPs) but also amplification of the aqueous silver nitrate (AgNO3) solutions' oxidative potentials were managed by vanadium pentoxide (V2O5) sol-gel nanofibers, which acted as well-known nanofibrous seeding agents and the auxiliary oxidative agent at the same time. The PANI/Ag nanocomposites were proven to exhibit excellent antibacterial property against both Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. Antibacterial property performance and average life span of the nanocomposite network were optimized through the homogeneous distribution/embedment of Ag NPs within one-dimensional (1-D) PANI NF matrix. The antibacterial efficacy tests and nanocomposite material characterization results further indicated that the sole components of PANI/Ag have a synergistic effect to each other in terms of antibacterial property. Thus, this well-known catalytic seeding approach via a one-step oxidative polymerization reaction can be considered as a general methodology and a substantial fabrication tool to synthesize Ag NP decorated nanofibrillar PANI networks as advanced antibacterial agents.

  16. Electroplating of nanostructured polyaniline-polypyrrole composite coating in a stainless-steel tube for on-line in-tube solid phase microextraction.

    PubMed

    Asiabi, Hamid; Yamini, Yadollah; Seidi, Shahram; Esrafili, Ali; Rezaei, Fatemeh

    2015-06-01

    In this work, a novel and efficient on-line in-tube solid phase microextraction method followed by high performance liquid chromatography was developed for preconcentration and determination of trace amounts of parabens. A nanostructured polyaniline-polypyrrole composite was electrochemically deposited on the inner surface of a stainless steel tube and used as the extraction phase. Several important factors that influence the extraction efficiency, including type of solid-phase coating, extraction and desorption times, flow rates of the sample solution and eluent, pH, and ionic strength of the sample solution were investigated and optimized. Under the optimal conditions, the limits of detection were in the range of 0.02-0.04 μg L(-1). This method showed good linearity for parabens in the range of 0.07-50 μg L(-1), with coefficients of determination better than 0.998. The intra- and inter-assay precisions (RSD%, n=3) were in the range of 5.9-7.0% and 4.4-5.7% at three concentration levels of 2, 10, and 20 μg L(-1), respectively. The extraction recovery values for the spiked samples were in the acceptable range of 80.3-90.2%. The validated method was successfully applied for analysis of methyl-, ethyl-, and propyl parabens in some water, milk, and juice samples.

  17. Polyacetylene and polyaniline: Synthesis, doping, and characterization

    SciTech Connect

    Swanson, D.B.

    1993-01-01

    Selected properties of two conducting polymers, viz., polyacetylene, (CH)[sub x], and polyaniline are studied. Polyacetylene. Reported values of conductivity for iodine-doped, non-aligned films of four types of polyacetylene, viz., S-(CH)[sub x], vary between 500 S/cm and 10,000 S/cm. the present study was carried out in order to understand why these different types of the same polymer have such different conductivities. the chief results and conclusions were: (i) through careful synthesis, purification and characterization of S-, N-, and [upsilon]-(CH)[sub x], it was concluded that while conductivity values of samples from a given synthesis are similar, they vary by up to [+-] 80% between different syntheses of the same type of (CH)[sub x]; (ii) films of N-(CH)[sub x] and [upsilon]-(CH)[sub x] both contain large and approximately equal amounts of catalyst impurities, as compared to films of S-(CH)[sub x], which contain essentially no impurity. It is concluded that impurities have no significant effect on the conductivity of these iodine-doped films. In order to ascertain optimum doping conditions for (CH)[sub x] films, an in-situ Impedance Profiling technique was developed to continually monitor the conductivity of the (CH)[sub x] during the actual redox or protonic acid doping process in aqueous and non-aqueous media. Polyaniline. A reported hysteresis in the conductivity of protonic acid doped polyaniline was studied using Impedance profiling. The chief results and conclusions were: (i) hysteresis was observed in pristine, NMP-cast polyaniline films only in the first doping/undoping cycle, but was absent in additional doping/undoping cycle.s It was concluded that the hysteresis was due to significant amounts of crystallinity in the pristine films, which was eliminated during the first doping/undoping cycle; (ii) the reported hysteresis in conductivity of polyaniline powder is amorphous, no hysteresis was observed at equilibrium, even in the first doping cycle.

  18. Polyaniline-based optical ammonia detector

    DOEpatents

    Duan, Yixiang; Jin, Zhe; Su, Yongxuan

    2002-01-01

    Electronic absorption spectroscopy of a polyaniline film deposited on a polyethylene surface by chemical oxidation of aniline monomer at room temperature was used to quantitatively detect ammonia gas. The present optical ammonia gas detector was found to have a response time of less than 15 s, a regeneration time of less than 2 min. at room temperature, and a detection limit of 1 ppm (v/v) for ammonia, with a linear dynamic range from 180 ppm to 18,000 ppm.

  19. Method for preparing polyaniline fibers

    DOEpatents

    Mattes, Benjamin R.; Wang, Hsing-Lin

    2000-01-01

    Stable, concentrated solutions of high molecular weight polyaniline. In order to process high quality fibers and other articles possessing good mechanical properties, it is known that solution concentrations of the chosen polymer should be in the range from 15-30% (w/w). Moreover, it is desirable to use the highest molecular weight consistent with the solubility properties of the polymer. However, such solutions are inherently unstable, forming gels before processing can be achieved. The present invention describes the addition gel inhibitors (GIs) to the polymer solution, thereby permitting high concentrations (>15% (w/w)) of high molecular weight ((M.sub.w)>120,000, and (M.sub.n)>30,000) emeraldine base (EB) polyaniline to be dissolved. Secondary amines have been used for this purpose in concentrations which are small compared to those which might otherwise be used in a cosolvent role therefor. The resulting solutions are useful for generating excellent fibers, films, coatings and other objects, since the solutions are stable for significant time periods, and the GIs are present in too small concentrations to cause polymer deterioration. It is demonstrated that the GIs found to be useful do not act as cosolvents, and that gelation times of the solutions are directly proportional to the concentration of GI. In particular, there is a preferred concentration of GI, which if exceeded causes structural and electrical conductivity degradation of resulting articles. Heating of the solutions significantly improves solubility.

  20. America on Film: A Humanities Composition Course.

    ERIC Educational Resources Information Center

    Recchia, Edward

    This paper argues that film courses are useful because they sensitize students both to the artistic qualities of film expression and to equivalent qualities in other forms of expression. The objectives of a film course at Michigan State University are: to develop the students' knowledge of the film medium and through that knowledge develop a…

  1. Polyaniline/cyclodextrin composite coated stir bar sorptive extraction combined with high performance liquid chromatography-ultraviolet detection for the analysis of trace polychlorinated biphenyls in environmental waters.

    PubMed

    Lei, Yun; He, Man; Chen, Beibei; Hu, Bin

    2016-04-01

    A novel polyaniline/α-cyclodextrin (PANI/α-CD) composite coated stir bar was prepared by sol-gel process for the analysis of polychlorinated biphenyls (PCBs) in this work. The preparation reproducibility of the PANI/α-CD-coated stir bar was good, with relative standard deviations (RSDs) ranging from 2.3% to 3.7% (n=7) and 2.0% to 3.8% (n=7) for bar to bar and batch to batch, respectively. Based on it, a novel method of PANI/α-CD-coated stir bar sorptive extraction (SBSE) followed by high performance liquid chromatography-ultraviolet (HPLC-UV) detection was developed for the determination of trace PCBs in environmental waters. To obtain the best extraction performance for target PCBs, several parameters affecting SBSE, such as extraction time, stirring rate, and ionic strength were investigated. Under optimal experimental conditions, the limits of detection (LODs) of the proposed method for seven PCBs were in the range of 0.048-0.22 μg/L, and the RSDs were 5.3-9.8% (n=7, c=1 μg/L). Enrichment factors (EFs) ranging from 39.8 to 68.4-fold (theoretical EF, 83.3-fold) for target analytes were achieved. The proposed method was successfully applied for the determination of seven target PCBs in Yangtze River water and East Lake water, and the recoveries were in the range of 73.0-120% for the spiked East Lake water samples and 82.7-121% for the spiked Yangtze River water samples, respectively. PMID:26838413

  2. Site-specific functionalization for chemical speciation of Cr(III) and Cr(VI) using polyaniline impregnated nanocellulose composite: equilibrium, kinetic, and thermodynamic modeling

    NASA Astrophysics Data System (ADS)

    Jain, Priyanka; Varshney, Shilpa; Srivastava, Shalini

    2015-10-01

    Site-specific functionalizations are the emergent attention for the enhancement of sorption latent of heavy metals. Limited chemistry has been applied for the fabrication of diafunctionalized materials having potential to tether both environmentally stable oxidation states of chromium (Cr(III) and Cr(VI). Polyaniline impregnated nanocellulose composite (PANI-NCC) has been fabricated using click chemistry and explored for the removal of Cr(III) and Cr(VI) from hydrological environment. The structure, stability, morphology, particle size, surface area, hydrophilicity, and porosity of fabricated PANI-NCC were characterized comprehensively using analytical techniques and mathematical tools. The maximum sorption performance of PANI-NCC was procured for (Cr(III): 47.06 mg g-1; 94.12 %) and (Cr(VI): 48.92 mg g-1; 97.84 %) by equilibrating 0.5 g sorbent dose with 1000 mL of 25 mg L-1 chromium conc. at pH 6.5 and 2.5 for Cr(III) and Cr(VI), respectively. The sorption data showed a best fit to the Langmuir isotherm and pseudo-second-order kinetic model. The negative value of ∆ G° (-8.59 and -11.16 kJ mol-1) and ∆ H° (66.46 × 10-1 and 17.84 × 10-1 kJ mol-1), and positive value of ∆ S° (26.66 and 31.46 J mol-1K-1) for Cr(III) and Cr(VI), respectively, reflect the spontaneous, feasibility, and exothermic nature of the sorption process. The application of fabricated PANI-NCC for removing both the forms of chromium in the presence of other heavy metals was also tested at laboratory and industrial waste water regime. These findings open up new avenues in the row of high performance, scalable, and economic nanobiomaterial for the remediation of both forms of chromium from water streams.

  3. Permeable polyaniline articles for gas separation

    DOEpatents

    Wang, Hsing-Lin; Mattes, Benjamin R.

    2004-09-28

    Immersion precipitation of solutions having 15%-30% (w/w) and various molecular weights of the emeraldine base form of polyaniline in polar aprotic solvents are shown to form integrally skinned asymmetric membranes and fibers having skin layers <1 .mu.m thick which exhibit improved rates of gas transport while preserving good selectivity. These membranes can be further transformed by an acid doping process after fabrication to achieve excellent permeation rates and high selectivities for particular gas separations. Prior to the use of concentrated EB solutions, the formation of integrally skinned asymmetric membranes was not possible, since films and fibers made from <5% w/w polyaniline solutions were found to disintegrate during the IP process.

  4. Permeable polyaniline articles for gas separation

    DOEpatents

    Wang, Hsing-Lin; Mattes, Benjamin R.

    2009-07-21

    Immersion precipitation of solutions having 15%-30% (w/w) and various molecular weights of the emeraldine base form of polyaniline in polar aprotic solvents are shown to form integrally skinned asymmetric membranes and fibers having skin layers <1 .mu.m thick which exhibit improved rates of gas transport while preserving good selectivity. These membranes can be further transformed by an acid doping process after fabrication to achieve excellent permeation rates and high selectivities for particular gas separations. Prior to the use of concentrated EB solutions, the formation of integrally skinned asymmetric membranes was not possible, since films and fibers made from <5% w/w polyaniline solutions were found to disintegrate during the IP process.

  5. Chitosan-graft-polyaniline-based hydrogels: elaboration and properties.

    PubMed

    Marcasuzaa, P; Reynaud, S; Ehrenfeld, F; Khoukh, A; Desbrieres, J

    2010-06-14

    Intrinsically conducting polymers are of great interest for a large number of applications. But among the major drawbacks are their low solubility in common solvents and their poor mechanical properties. Elaboration of composites associating a matrix, bringing its mechanical properties, and polyaniline, as the conducting polymer, is a way of overcoming these disadvantages. Chitosan-graft-polyaniline copolymers were synthesized by simple oxidative method. The grafting reaction was quite complete, and it was found that the copolymers cross-linked to yield a composite hydrogel in which the polyaniline was homogeneously embedded. The conductivity of precursor (block copolymer) and gels was found to be larger than 10(-2) S x cm(-1). The composite gels were characterized in terms of swelling and rheological properties. They can be classified as "superabsorbent" hydrogels, and the swelling is reversible. The composite gels were then successfully used as actuators.

  6. Coassembly of gold nanoparticles and cellulose nanocrystals in composite films.

    PubMed

    Lukach, Ariella; Thérien-Aubin, Héloïse; Querejeta-Fernández, Ana; Pitch, Natalie; Chauve, Grégory; Méthot, Myriam; Bouchard, Jean; Kumacheva, Eugenia

    2015-05-12

    Coassembly of nanoparticles with different size-, shape-, and composition-dependent properties is a promising approach to the design and fabrication of functional materials and devices. This paper reports the results of a detailed investigation of the formation and properties of free-stranding composite films formed by the coassembly of cellulose nanocrystals and shape-isotropic plasmonic gold nanoparticles. The effect of gold nanoparticle size, surface charge, and concentration on the structural and optical properties of the composite films has been studied. The composite films retained photonic crystal and chiroptical activity properties. The size and surface charge of gold nanoparticles had a minor effect on the structure and properties of the composite films, while the concentration of gold nanoparticles in the composite material played a more significant role and can be used to fine-tune the optical properties of materials derived from cellulose nanocrystals. These findings significantly broaden the range of nanoparticles that can be used for producing nanocomposite materials based on cellulose nanocrystals. The simplicity of film preparation, the abundance of cellulose nanocrystals, and the robust, free-standing nature of the composite films offer highly advantageous features and pave the way for the generation of functional materials with coupled optical properties.

  7. Film in the Advanced Composition Classroom: A Tapestry of Style

    ERIC Educational Resources Information Center

    Durst, Pearce

    2015-01-01

    This article advances film as worthy of rhetorical inquiry and deserving of more sustained attention in the advanced composition classroom. The first section identifies various approaches to the "language" of film, which can be adopted to navigate the technical, rhetorical, and cultural concerns needed to compose informed multimodal…

  8. Adhesion, Proliferation and Migration of NIH/3T3 Cells on Modified Polyaniline Surfaces

    PubMed Central

    Rejmontová, Petra; Capáková, Zdenka; Mikušová, Nikola; Maráková, Nela; Kašpárková, Věra; Lehocký, Marián; Humpolíček, Petr

    2016-01-01

    Polyaniline shows great potential and promises wide application in the biomedical field thanks to its intrinsic conductivity and material properties, which closely resemble natural tissues. Surface properties are crucial, as these predetermine any interaction with biological fluids, proteins and cells. An advantage of polyaniline is the simple modification of its surface, e.g., by using various dopant acids. An investigation was made into the adhesion, proliferation and migration of mouse embryonic fibroblasts on pristine polyaniline films and films doped with sulfamic and phosphotungstic acids. In addition, polyaniline films supplemented with poly (2-acrylamido-2-methyl-1-propanesulfonic) acid at various ratios were tested. Results showed that the NIH/3T3 cell line was able to adhere, proliferate and migrate on the pristine polyaniline films as well as those films doped with sulfamic and phosphotungstic acids; thus, utilization of said forms in biomedicine appears promising. Nevertheless, incorporating poly (2-acrylamido-2-methyl-1-propanesulfonic) acid altered the surface properties of the polyaniline films and significantly affected cell behavior. In order to reveal the crucial factor influencing the surface/cell interaction, cell behavior is discussed in the context of the surface energy of individual samples. It was clearly demonstrated that the lesser the difference between the surface energy of the sample and cell, the more cyto-compatible the surface is. PMID:27649159

  9. Adhesion, Proliferation and Migration of NIH/3T3 Cells on Modified Polyaniline Surfaces.

    PubMed

    Rejmontová, Petra; Capáková, Zdenka; Mikušová, Nikola; Maráková, Nela; Kašpárková, Věra; Lehocký, Marián; Humpolíček, Petr

    2016-01-01

    Polyaniline shows great potential and promises wide application in the biomedical field thanks to its intrinsic conductivity and material properties, which closely resemble natural tissues. Surface properties are crucial, as these predetermine any interaction with biological fluids, proteins and cells. An advantage of polyaniline is the simple modification of its surface, e.g., by using various dopant acids. An investigation was made into the adhesion, proliferation and migration of mouse embryonic fibroblasts on pristine polyaniline films and films doped with sulfamic and phosphotungstic acids. In addition, polyaniline films supplemented with poly (2-acrylamido-2-methyl-1-propanesulfonic) acid at various ratios were tested. Results showed that the NIH/3T3 cell line was able to adhere, proliferate and migrate on the pristine polyaniline films as well as those films doped with sulfamic and phosphotungstic acids; thus, utilization of said forms in biomedicine appears promising. Nevertheless, incorporating poly (2-acrylamido-2-methyl-1-propanesulfonic) acid altered the surface properties of the polyaniline films and significantly affected cell behavior. In order to reveal the crucial factor influencing the surface/cell interaction, cell behavior is discussed in the context of the surface energy of individual samples. It was clearly demonstrated that the lesser the difference between the surface energy of the sample and cell, the more cyto-compatible the surface is. PMID:27649159

  10. Adhesion, Proliferation and Migration of NIH/3T3 Cells on Modified Polyaniline Surfaces.

    PubMed

    Rejmontová, Petra; Capáková, Zdenka; Mikušová, Nikola; Maráková, Nela; Kašpárková, Věra; Lehocký, Marián; Humpolíček, Petr

    2016-09-15

    Polyaniline shows great potential and promises wide application in the biomedical field thanks to its intrinsic conductivity and material properties, which closely resemble natural tissues. Surface properties are crucial, as these predetermine any interaction with biological fluids, proteins and cells. An advantage of polyaniline is the simple modification of its surface, e.g., by using various dopant acids. An investigation was made into the adhesion, proliferation and migration of mouse embryonic fibroblasts on pristine polyaniline films and films doped with sulfamic and phosphotungstic acids. In addition, polyaniline films supplemented with poly (2-acrylamido-2-methyl-1-propanesulfonic) acid at various ratios were tested. Results showed that the NIH/3T3 cell line was able to adhere, proliferate and migrate on the pristine polyaniline films as well as those films doped with sulfamic and phosphotungstic acids; thus, utilization of said forms in biomedicine appears promising. Nevertheless, incorporating poly (2-acrylamido-2-methyl-1-propanesulfonic) acid altered the surface properties of the polyaniline films and significantly affected cell behavior. In order to reveal the crucial factor influencing the surface/cell interaction, cell behavior is discussed in the context of the surface energy of individual samples. It was clearly demonstrated that the lesser the difference between the surface energy of the sample and cell, the more cyto-compatible the surface is.

  11. Fabrication and Characterization of Polyaniline/PVA Humidity Microsensors

    PubMed Central

    Yang, Ming-Zhi; Dai, Ching-Liang; Lin, Wei-Yi

    2011-01-01

    This study presents the fabrication and characterization of a humidity microsensor that consists of interdigitated electrodes and a sensitive film. The area of the humidity microsensor is about 2 mm2. The sensitive film is polyaniline doping polyvinyl alcohol (PVA) that is prepared by the sol-gel method, and the film has nanofiber and porous structures that help increase the sensing reaction. The commercial 0.35 μm Complimentary Metal Oxide Semiconductor (CMOS) process is used to fabricate the humidity microsensor. The sensor needs a post-CMOS process to etch the sacrificial layer and to coat the sensitive film on the interdigitated electrodes. The sensor produces a change in resistance as the polyaniline/PVA film absorbs or desorbs vapor. Experimental results show that the sensitivity of the humidity sensor is about 12.6 kΩ/%RH at 25 °C. PMID:22164067

  12. English Composition and the Feature Film.

    ERIC Educational Resources Information Center

    Moss, Robert F.

    1985-01-01

    Discusses film-oriented writing classes as a way of expanding student vocabularies and illustrating such literary devices as metaphor, irony, and imagery. Offers guidelines for writing instructors wishing to add films to a course plan, using "King Kong,""The Godfather," and "One Flew Over the Cuckoo's Nest" as examples. (DMM)

  13. Piezoelectric Sol-Gel Composite Film Fabrication by Stencil Printing.

    PubMed

    Kaneko, Tsukasa; Iwata, Kazuki; Kobayashi, Makiko

    2015-09-01

    Piezoelectric films using sol-gel composites could be useful as ultrasonic transducers in various industrial fields. For sol-gel composite film fabrication, the spray coating technique has been used often because of its adaptability for various substrates. However, the spray technique requires multiple spray coating processes and heating processes and this is an issue of concern, especially for on-site fabrication in controlled areas. Stencil printing has been developed to solve this issue because this method can be used to fabricate thick sol-gel composite films with one coating process. In this study, PbTiO3 (PT)/Pb(Zr,Ti)O3 (PZT) films, PZT/PZT films, and Bi4Ti3O12 (BiT)/PZT films were fabricated by stencil printing, and PT/ PZT films were also fabricated using the spray technique. After fabrication, a thermal cycle test was performed for the samples to compare their ultrasonic performance. The sensitivity and signal-to-noise-ratio (SNR) of the ultrasonic response of PT/PZT fabricated by stencil printing were equivalent to those of PT/PZT fabricated by the spray technique, and better than those of other samples between room temperature and 300°C. Therefore, PT/PZT films fabricated by stencil printing could be a good candidate for nondestructive testing (NDT) ultrasonic transducers from room temperature to 300°C. PMID:26688872

  14. Microstructures and thermochromic characteristics of VO2/AZO composite films

    NASA Astrophysics Data System (ADS)

    Xiao, Han; Li, Yi; Yuan, Wenrui; Fang, Baoying; Wang, Xiaohua; Hao, Rulong; Wu, Zhengyi; Xu, Tingting; Jiang, Wei; Chen, Peizu

    2016-05-01

    A vanadium dioxide (VO2) thin film was fabricated on a ZnO doped with Al (AZO) conductive glass by magnetron sputtering at room temperature followed by annealing under air atmosphere. The microstructures and optical properties of the thin film were studied. The results showed that the VO2/AZO composite film was poly-crystalline and the AZO layer did not change the preferred growth orientation of VO2. Compared to the VO2 film fabricated on soda-lime glass substrate through the same process and condition, the phase transition temperature of the VO2/AZO composite film was decreased by about 25 °C, thermal hysteresis width narrowed to 6 °C, the visible light transmittance was over 50%, the infrared transmittances before and after phase transition were 21% and 55%, respectively at 1500 nm.

  15. Investigation of methanol oxidation on a highly active and stable Pt–Sn electrocatalyst supported on carbon–polyaniline composite for application in a passive direct methanol fuel cell

    SciTech Connect

    Amani, Mitra; Kazemeini, Mohammad; Hamedanian, Mahboobeh; Pahlavanzadeh, Hassan; Gharibi, Hussein

    2015-08-15

    Highlights: • PtSn/C-PANI performed superior in the MOR compared with a commercial PtRu/C. • Catalytic activity of PtRu/C was highly reduced during the accelerated durability test. • Anode of the PtSn/C-PANI in a passive DMFC lowered methanol crossover by 30%. - Abstract: Polyaniline fiber (PANI) was synthesized and utilized to fabricate a vulcan–polyaniline (C-PANI) composite. Pt/C-PANI and PtSn/C-PANI electro-catalysts with different Pt:Sn atomic ratios were prepared by the impregnation method. These electro-catalysts, along with commercial PtRu/C (Electrochem), were characterized with respect to their structural and electrochemical properties in methanol oxidation reaction (MOR). PtSn(70:30)/C-PANI showed excellent performance in MOR, the obtained maximum current density being about 40% and 50% higher than that for PtRu/C and Pt/C-PANI, respectively. It was also found that the CO tolerance and stability of PtSn(70:30)/C-PANI was considerably higher than that of PtRu/C. Finally, the performance of these two materials was compared in a passive direct methanol fuel cell (DMFC). The DMFC test results demonstrated that the membrane electrode assembly (MEA) prepared using PtSn(70:30)/C-PANI anode catalyst performed more satisfactorily in terms of maximum power density and lower methanol crossover.

  16. Photo-induced polymerization of polyaniline

    SciTech Connect

    Barros, R.A. de; Azevedo, W.M. de; Aguiar, F.M. de

    2003-03-15

    A straightforward route to prepare polyaniline is presented in which photons and metallic ions replace conventional oxidants to promote polymerization of aniline monomer. The photopolymerization methods yield a composite material that has been characterized by its UV, visible and Raman spectroscopic analysis and by scanning electron microscopy and X-ray microanalysis as well. Intriguing forms of silver wires embedded in polyaniline are observed, typically of 1 {mu}m wide and up to 100 {mu}m long. It is shown that the morphology of the resulting conducting polymer strongly depends on the excitation wavelength, while a globular morphology is found for the UV synthesis and a fibrillar one is found for visible light excitation.

  17. Synthesis and characterization of polyaniline nanorods/Ce(OH){sub 3}-Pr{sub 2}O{sub 3}/montmorillonite composites through reverse micelle template

    SciTech Connect

    Mo Zunli Zhang Ping; Zuo Dandan; Sun Yaling; Chen Hong

    2008-07-01

    Polyaniline (PANI) nanorods/Ce(OH){sub 3}-Pr{sub 2}O{sub 3}/montmorillonite (MMT) nanocomposites were synthesized via in situ polymerization of aniline monomer through reverse micelle template (RMT) in the presence of montmorillonite and Ce(OH){sub 3}, Pr{sub 2}O{sub 3}. In the experiment, sulphosalicylic acid was used as dopant, aniline was designated as oil phase and the aqueous solution comprising Ce{sup 3+} and Pr{sup 3+} as water phase. The nanocomposites were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) analysis, Fourier transform infrared (FT-IR) spectroscopy and thermogravimetry-differential thermal analysis (TG-DTA). The results showed that PANI nanorods were synthesized in the interlayer spaces of MMT with uniform spherical rare earth nanoparticles. The thermal stability of the nanocomposites prepared was enhanced drastically compared with pure polyaniline.

  18. Fabrication and characterization of polysulfone-dicalcium silicate composite films.

    PubMed

    Cheng, Wei; Chang, Jiang

    2006-04-01

    Polysulfone (PSU) composite films filled with Beta-dicalcium silicate (Beta-Ca(2)SiO(4)) particles are prepared by the solvent casting-evaporation method. The surface morphologies and mechanical properties of the films are determined. The bioactivity of the composite films is evaluated by soaking them in simulated body fluid (SBF) and the results show that the composites are bioactive as they induce the formation of hydroxyapatite (HAp) on the surface of the composite films. The measurement of the water contact angles suggests that the incorporation of Beta-Ca(2)SiO(4) particles into PSU matrix can improve the hydrophilicity of the composite. PSU composite films filled with modified Beta-dicalcium silicate (Beta-mCa(2)SiO(4)) particles are also prepared after Beta-Ca(2)SiO(4) particles are treated with dodecyl alcohol through surface esterification reactions. The infrared spectra of the Beta-mCa(2)SiO(4) particles before and after aging in water indicate that the surface modification is reversible. The scanning electron microscope (SEM) images (micrographs) of both composites show that the dispersion of inorganic particles in the polymer matrix improves after surface modification. The PSU-Beta-mCa(2)SiO(4) composite is still bioactive and exhibits the same water contact angle after aging in water as compared to that of the PSU-Beta-Ca(2)SiO(4) composite. All these results suggest that the incorporation of Beta-Ca(2)SiO(4) particles is a useful method to prepare composites with improved bioactivity and hydrophilicity, and the surface modification of Beta-Ca(2)SiO(4) particles can improve the dispersion while retaining the bioactivity and hydrophilicity.

  19. Sprayable, Paintable Layer-by-Layer Polyaniline Nanofiber/Graphene Electrodes for Electrochemical Energy Storage

    NASA Astrophysics Data System (ADS)

    Kwon, Se Ra; Jeon, Ju-Won; Lutkenhus, Jodie

    2015-03-01

    Sprayable batteries are growing in interest for applications in structural energy storage and power or flexible power. Spray-assisted layer-by-layer (LbL) assembly, in which complementary species are alternately sprayed onto a surface, is particularly amenable toward this application. Here, we report on the fabrication of composite films containing polyaniline nanofibers (PANI NF) and graphene oxide (GO) sheets fabricated via spray-assisted LbL assembly. The resulting films are electrochemical reduced to yield PANI NF/electrochemically reduced graphene (ERGO) electrodes for use as a cathode in non-aqueous energy storage systems. Through the spray-assisted LbL process, the hybrid electrodes could be fabricated 74 times faster than competing dip-assisted LbL assembly. The resulting electrodes are highly porous (0.72 void fraction), and are comprised of 67 wt% PANI NF and 33 wt% ERGO. The sprayed electrodes showed better rate capability, higher specific power, as well as more stable cycle life than dip-assisted LbL electrodes. It is shown here that the spray-assisted LbL approach is well-suited towards the fabrication of paintable electrodes containing polyaniline nanofibers and electrochemically reduced graphene oxide sheets.

  20. Synthesis and characterization of silver-polypyrrole film composite

    NASA Astrophysics Data System (ADS)

    Ayad, Mohamad. M.; Zaki, Eman

    2009-11-01

    In this work, we report the chemical polymerization of pyrrole to obtain thin film of polypyrrole (PPy) hydrochloride deposited onto the electrode of the quartz crystal microbalance (QCM). The film in the base form was exposed to a solution of AgNO 3. Electroless reduction for silver ions by the PPy film took place and silver particles were adsorbed onto the film surface. The silver particles content at the PPy films were analyzed by QCM and the results showed that the concentrations of silver uptakes increase as the original AgNO 3 solution increases. The morphology of the surface of the PPy film and the silver-PPy film composite were studied by the scanning electron microscopy (SEM) coupled with energy dispersive X-ray spectrometry (EDX). They showed that the obtained silver particles have spherical, cubic and tetrahedral structures. X-ray diffraction (XRD) and Fourier transformed infra-red spectroscopy (FTIR) were used to characterize the structure of the powder composite. This work reveals the capability of PPy film coating on QCM in sensing and removing silver from several environmental samples.

  1. Tuning of wettability of PANI-GNP composites using keV energy ions

    NASA Astrophysics Data System (ADS)

    Lakshmi, G. B. V. S.; Avasthi, D. K.

    2016-07-01

    Polyaniline nanofiber composites with various nanomaterials have several applications in electrochemical biosensors. The surface properties of these composites coated electrodes play crucial role in enzyme absorption and analyte detection process. In the present study, Polyaniline-Graphene nanopowder (PANI-GNP) composites were prepared by rapid-mixing polymerization method. The films were prepared on ITO coated glass substrates and irradiated with 42 keV He+ ions produced by indigenously fabricated accelerator at IUAC, New Delhi. The films were characterized before and after irradiation by SEM, Raman spectroscopy and contact angle measurements. The as-prepared films show superhydrophilic nature and after irradiation the films show highly hydrophobic nature with water contact angle (135°). The surface morphology was studied by SEM and structural changes were studied by Raman spectra. The surface morphological modifications induced by keV energy ions helps in tuning the wettability at different ion fluences.

  2. Compositional depth profiling of TaCN thin films

    SciTech Connect

    Adelmann, Christoph; Conard, Thierry; Franquet, Alexis; Brijs, Bert; Munnik, Frans; Burgess, Simon; Witters, Thomas; Meersschaut, Johan; Kittl, Jorge A.; Vandervorst, Wilfried; Van Elshocht, Sven

    2012-07-15

    The composition profiling of thin TaCN films was studied. For the composition profile determination using x-ray photoemission spectrometry (XPS) in combination with Ar sputtering, preferential sputtering effects of N with respect to Ta and C were found to lead to inaccurate elemental concentrations. Sputter yield calculations for the given experimental conditions allowed for the correction of a part of the error, leading to fair accuracy by reference-free measurements. Further improvement of the accuracy was demonstrated by the calibration of the XPS compositions against elastic recoil detection analysis (ERDA) results. For Auger electron spectrometry (AES) in combination with Ar sputtering, accurate results required the calibration against ERDA. Both XPS and AES allowed for a reliable and accurate determination of the compositional profiles of TaCN-based thin films after calibration. Time-of-flight secondary-ion mass spectrometry was also used to assess the composition of the TaCN films. However, the analysis was hampered by large matrix effects due to small unintentional oxygen contents in the films. Energy-dispersive x-ray spectrometry is also discussed, and it is shown that an accurate reference-free measurement of the average film concentration can be achieved.

  3. [Spectroscopic study on film formation mechanism and structure of composite silanes-V-Zr passive film].

    PubMed

    Wang, Lei; Liu, Chang-sheng; Shi, Lei; An, Cheng-qiang

    2015-02-01

    A composite silanes-V-Zr passive film was overlayed on hot-dip galvanized steel. Attenuated total reflection Fourier transformed infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectrometer (XPS) and radio frequency glow discharge optical emission spectrometry (rf-GD-OES) were used to characterize the molecular structure of the silanes-V-Zr passive film. The mechanism of film formation was discussed: The results show that the silane molecules are crosslinked as the main film former and inorganic inhibitor is even distributed in the film. The fitting peak of 100.7 eV in XPS single Si2p energy range spectra of the composite silanes-V-Zr passive film and the widening and strengthening of the Si--O infrared absorption peak at 1100 cm(-1) indicate that the silanes were adsorbed on the surface of zinc with chemical bond of Si--O--Zn, and the silane molecules were connected with each other by bond of Si--O--Si. Two characteristic absorption peaks of amide at 1650 and 1560 cm(-1) appear in the infrared spectroscopy of the composite silanes-V-Zr passive film, and a characteristic absorption peak of epoxy groups at 910 cm(-1) disappears in the infrared spectroscopy of the passive film. The results indicate that gamma-APT can be prepared through nucleophilic ring-opening of ethylene oxide in gamma-GPT molecule to form C--N covalent bonds. The rf-GD-OES results indicate that there is a oxygen enriched layer in 0.3 microm depth of the composite silanes-V-Zr passive film. Moreover, ZrF4, ZrO2 and some inorganic matter obtained by the reaction during the forming processof the composite silanes-V-Zr passive film are distributed evenly throughout the film. According to the film composition, the physical processes and chemical reactions during the film forming process were studied by using ATR-FTIR. Based on this, the film forming mechanism was proposed. PMID:25970911

  4. [Spectroscopic study on film formation mechanism and structure of composite silanes-V-Zr passive film].

    PubMed

    Wang, Lei; Liu, Chang-sheng; Shi, Lei; An, Cheng-qiang

    2015-02-01

    A composite silanes-V-Zr passive film was overlayed on hot-dip galvanized steel. Attenuated total reflection Fourier transformed infrared spectroscopy (ATR-FTIR), X-ray photoelectron spectrometer (XPS) and radio frequency glow discharge optical emission spectrometry (rf-GD-OES) were used to characterize the molecular structure of the silanes-V-Zr passive film. The mechanism of film formation was discussed: The results show that the silane molecules are crosslinked as the main film former and inorganic inhibitor is even distributed in the film. The fitting peak of 100.7 eV in XPS single Si2p energy range spectra of the composite silanes-V-Zr passive film and the widening and strengthening of the Si--O infrared absorption peak at 1100 cm(-1) indicate that the silanes were adsorbed on the surface of zinc with chemical bond of Si--O--Zn, and the silane molecules were connected with each other by bond of Si--O--Si. Two characteristic absorption peaks of amide at 1650 and 1560 cm(-1) appear in the infrared spectroscopy of the composite silanes-V-Zr passive film, and a characteristic absorption peak of epoxy groups at 910 cm(-1) disappears in the infrared spectroscopy of the passive film. The results indicate that gamma-APT can be prepared through nucleophilic ring-opening of ethylene oxide in gamma-GPT molecule to form C--N covalent bonds. The rf-GD-OES results indicate that there is a oxygen enriched layer in 0.3 microm depth of the composite silanes-V-Zr passive film. Moreover, ZrF4, ZrO2 and some inorganic matter obtained by the reaction during the forming processof the composite silanes-V-Zr passive film are distributed evenly throughout the film. According to the film composition, the physical processes and chemical reactions during the film forming process were studied by using ATR-FTIR. Based on this, the film forming mechanism was proposed.

  5. Composite polymeric film and method for its use in installing a very-thin polymeric film in a device

    DOEpatents

    Duchane, D.V.; Barthell, B.L.

    1982-04-26

    A composite polymeric film and a method for its use in forming and installing a very thin (< 10 ..mu..m) polymeric film are disclosed. The composite film consists of a thin film layer and a backing layer. The backing layer is soluble in a solvent in which the thin film layer is not soluble. In accordance with the method, the composite film is installed in a device in the same position in which it is sought to finally emplace the thin film. The backing layer is then selectiely dissolved in the solvent to leave the insoluble thin film layer as an unbacked film. The method permits a very thin film to e successfully installed in devices where the fragility of the film would preclude handling and installation by conventional methods.

  6. Composite polymeric film and method for its use in installing a very thin polymeric film in a device

    DOEpatents

    Duchane, David V.; Barthell, Barry L.

    1984-01-01

    A composite polymeric film and a method for its use in forming and installing a very thin (<10 .mu.m) polymeric film are disclosed. The composite film consists of a thin film layer and a backing layer. The backing layer is soluble in a solvent in which the thin film layer is not soluble. In accordance with the method, the composite film is installed in a device in the same position in which it is sought to finally emplace the thin film. The backing layer is then selectively dissolved in the solvent to leave the insoluble thin film layer as an unbacked film. The method permits a very thin film to be successfully installed in devices where the fragility of the film would preclude handling and installation by conventional methods.

  7. Structural and magnetic properties of Co-C composite films and Co/C multilayer films

    NASA Astrophysics Data System (ADS)

    Shi, J.; Azumi, M.; Nittono, O.

    CoC composite films and Co/C multilayer films have been prepared by a method incorporating ion beam sputtering and plasma chemical vapor deposition. It has been found that the structure and magnetic properties of both the Co-C composite and the Co/C multilayer films depend strongly on the substrate temperature during deposition. The Co-C composite film deposited at room temperature is amorphous, with relatively low saturation magnetization and coercivity. On the other hand, the film deposited at 250 °C is composed of fine Co crystallites separated by amorphous C or Co-C phase. As a result, both the saturation magnetization and coercivity are increased compared with the film deposited at room temperature. When deposited at room temperature, the Co/C multilayer film exhibits good periodicity, with a period of 70 nm (Co: 40 nm, C: 30 nm) and sharp and flat Co-C interfaces. High magnetization (602 emu/cm3) and low coercivity (1.6 Oe) are obtained for such a film. However, increasing the substrate temperature to 250 °C was found to be detrimental to the magnetic properties due to the formation of cobalt carbide at the Co-C interface.

  8. Stabilization of polyaniline solutions

    SciTech Connect

    Wrobleski, D.A.; Benicewicz, B.C.

    1993-12-01

    Adding hindered amine light stabilizers (HALS) to N-methyl- pyrrolidinone (NMP) solutions of polyaniline delays gelation. It is hypothesized that HALS act in some manner other than as traditional antioxidants in preventing gelation; the secondary amine functional group appears to play a critical role, perhaps by disrupting the physical crystallization network that may contribute to gelation. Pyrrolidine, a secondary amine, or ammonia is an effective cosolvent with NMP in dissolving PAn-EB (emeraldine base). 6 refs, 4 figs.

  9. Novel hybrid multifunctional magnetoelectric porous composite films

    NASA Astrophysics Data System (ADS)

    Martins, P.; Gonçalves, R.; Lopes, A. C.; Venkata Ramana, E.; Mendiratta, S. K.; Lanceros-Mendez, S.

    2015-12-01

    Novel multifunctional porous films have been developed by the integration of magnetic CoFe2O4 (CFO) nanoparticles into poly(vinylidene fluoride)-Trifuoroethylene (P(VDF-TrFE)), taking advantage of the synergies of the magnetostrictive filler and the piezoelectric polymer. The porous films show a piezoelectric response with an effective d33 coefficient of -22 pC/N-1, a maximum magnetization of 12 emu g-1 and a maximum magnetoelectric coefficient of 9 mV cm-1 Oe-1. In this way, a multifunctional membrane has been developed suitable for advanced applications ranging from biomedical to water treatment.

  10. Tunneling studies of compositionally modulated PB/Fe films

    SciTech Connect

    Wawro, A.; Witek, A.; Majewski, J.; Rauluszkiewicz, J.; Nowak, J. )

    1988-01-01

    Preliminary results of preparation and investigation of compositionally modulated Pb/Fe films are reported. These films have been used as electrodes in Al/Al/sub 2/O/sub 3//{kappa}(Pb/Fe) tunnel junctions and the tunnelling characteristics I-V, dV/dI and d/sup 2/V/d/I/sup 2/ vs V have been studied in dependence on the modulation period.

  11. The effective flux through a thin-film composite membrane

    NASA Astrophysics Data System (ADS)

    Bruna, M.; Chapman, S. J.; Ramon, G. Z.

    2015-05-01

    Composite membrane structures, used extensively in separation processes, comprise an ultra-thin selective polymer film cast over a porous support, whose pores partially obstruct transport out of the top film. Here, we model the composite as a finite thickness slab with a periodic array of circular absorbing patches in an otherwise reflective surface and study the effective transport properties of the composite. We obtain an analytical approximation for the effective diffusive flux as a function of the geometrical parameters, namely the film thickness, the support porosity and the pore size. We find a good agreement with full numerical solutions, and that a good effective rate is achievable with a relatively small number of pores.

  12. The sorption of influenza viruses and antibiotics on carbon nanotubes and polyaniline nanocomposites

    NASA Astrophysics Data System (ADS)

    Ivanova, V. T.; Katrukha, G. S.; Timofeeva, A. V.; Ilyna, M. V.; Kurochkina, Y. E.; Baratova, L. A.; Sapurina, I. Yu; Ivanov, V. F.

    2011-04-01

    The decontamination of the solutions from micropatogens and drug delivery are the important problems of modern life. It was shown that carbon nanotubes, polyaniline and their composites can interact with antibiotics-polypeptides and some viruses (pandemic strain of influenza viruses A(H1N1)v circulated in Russia in 2009-2010. During a short time drug and viruses can be absorbed by polyaniline and removed from aqueous solutions at the normal conditions. Polyaniline composites can be useful for the preparation of drug delivery and virus control filters and also in biotechnology for the improvement the methods of antibiotics purification.

  13. Composite elastic magnet films with hard magnetic feature

    NASA Astrophysics Data System (ADS)

    Wang, Weisong; Yao, Zhongmei; Chen, Jackie C.; Fang, Ji

    2004-10-01

    Hard magnetic materials with high remnant magnetic moment, Mr, have unique advantages that can achieve bi-directional (push-pull) movement in an external magnetic field. This paper presents the results on the fabrication and testing of novel composite elastic permanent magnet films. The microsize hard barium ferrite powder, NdFeB powder, and different silicone elastomers have been used to fabricate various large elongation hard magnetic films. Three different fabrication methods, screen-coating processing, moulding processing and squeegee-coating processing, have been investigated, and the squeegee-coating process was proven to be the most successful method. The uniform composite elastic permanent magnet films range from 40 µm to 216 µm in thickness have been successfully fabricated. These films were then magnetized in the thickness direction after fabrication. They exhibited permanent magnet behaviour; for instance, the film (0.640 mm3 in volume) made of polydimethyl siloxane (PDMS) and hard barium ferrite powders is measured to give a coercive force, Hc, of 3.24 × 105 A m-1 and Mr of 1.023 × 10-5 A m2, and the film (0.504 mm3 in volume) made of PDMS and NdFeB powders gives 1.55 × 105 A m-1 Hc and 8.081 × 10-5 A m2 Mr. These composite elastic permanent magnet films' mechanical properties, like Young's modulus and deflection force, have been evaluated. To validate the films' Young's modulus, a finite-element computer simulation (ANSYS®) is used and one film is chosen whose Young's modulus (16.60 MPa) is confirmed by the simulation results with ANSYS®. The large elongation composite elastic permanent magnet film provides an excellent diaphragm material, which plays an important role in the micropump or valve. The movement of the 126 µm thick film with 4.5 mm diameter made of PDMS and NdFeB powders has been tested in a 0.21 Tesla external magnetic field. It was proven to have large deflection of 125 µm.

  14. Flexible composite film for printed circuit board

    NASA Technical Reports Server (NTRS)

    Yabe, K.; Asakura, M.; Tanaka, H.; Soda, A.

    1982-01-01

    A flexible printed circuit for a printed circuit board in which layers of reaction product composed of a combination of phenoxy resin - polyisocyanate - brominated epoxy resin, and in which the equivalent ratio of those functional groups is hydroxyl group: isocyanate group: epoxy group - 1 : 0.2 to 2 : 0.5 to 3 are laminated on at least one side of saturated polyester film is discussed.

  15. DIFFUSION IN CRYSTALLINE COMPOSITION-MODULATED FILMS

    SciTech Connect

    Jankowski, A; Saw, C; Harper, J

    2004-12-16

    The diffusivity in alloys at low temperatures is modeled for composition-modulated structures using Khachaturyan's microscopic theory of diffusion. The theory is now applied to assess a two-phase multilayer system.

  16. Physical and mechanical properties of modified bacterial cellulose composite films

    NASA Astrophysics Data System (ADS)

    Indrarti, Lucia; Indriyati, Syampurwadi, Anung; Pujiastuti, Sri

    2016-02-01

    To open wide range application opportunities of Bacterial Cellulose (BC) such as for agricultural purposes and edible film, BC slurries were blended with Glycerol (Gly), Sorbitol (Sor) and Carboxymethyl Cellulose (CMC). The physical and mechanical properties of BC composites were investigated to gain a better understanding of the relationship between BC and the additive types. Addition of glycerol, sorbitol and CMC influenced the water solubility of BC composite films. FTIR analysis showed the characteristic bands of cellulose. Addition of CMC, glycerol, and sorbitol slightly changed the FTIR spectrum of the composites. Tensile test showed that CMC not only acted as cross-linking agent where the tensile strength doubled up to 180 MPa, but also acted as plasticizer with the elongation at break increased more than 100% compared to that of BC film. On the other hand, glycerol and sorbitol acted as plasticizers that decreased the tensile strength and increased the elongation. Addition of CMC can improve film transparency, which is quite important in consumer acceptance of edible films in food industry.

  17. Nanocellulose-Zeolite Composite Films for Odor Elimination.

    PubMed

    Keshavarzi, Neda; Mashayekhy Rad, Farshid; Mace, Amber; Ansari, Farhan; Akhtar, Farid; Nilsson, Ulrika; Berglund, Lars; Bergström, Lennart

    2015-07-01

    Free standing and strong odor-removing composite films of cellulose nanofibrils (CNF) with a high content of nanoporous zeolite adsorbents have been colloidally processed. Thermogravimetric desorption analysis (TGA) and infrared spectroscopy combined with computational simulations showed that commercially available silicalite-1 and ZSM-5 have a high affinity and uptake of volatile odors like ethanethiol and propanethiol, also in the presence of water. The simulations showed that propanethiol has a higher affinity, up to 16%, to the two zeolites compared with ethanethiol. Highly flexible and strong free-standing zeolite-CNF films with an adsorbent loading of 89 w/w% have been produced by Ca-induced gelation and vacuum filtration. The CNF-network controls the strength of the composite films and 100 μm thick zeolite-CNF films with a CNF content of less than 10 vol % displayed a tensile strength approaching 10 MPa. Headspace solid phase microextraction (SPME) coupled to gas chromatography-mass spectroscopy (GC/MS) analysis showed that the CNF-zeolite films can eliminate the volatile thiol-based odors to concentrations below the detection ability of the human olfactory system. Odor removing zeolite-cellulose nanofibril films could enable improved transport and storage of fruits and vegetables rich in odors, for example, onion and the tasty but foul-smelling South-East Asian Durian fruit. PMID:26061093

  18. Nanocellulose-Zeolite Composite Films for Odor Elimination.

    PubMed

    Keshavarzi, Neda; Mashayekhy Rad, Farshid; Mace, Amber; Ansari, Farhan; Akhtar, Farid; Nilsson, Ulrika; Berglund, Lars; Bergström, Lennart

    2015-07-01

    Free standing and strong odor-removing composite films of cellulose nanofibrils (CNF) with a high content of nanoporous zeolite adsorbents have been colloidally processed. Thermogravimetric desorption analysis (TGA) and infrared spectroscopy combined with computational simulations showed that commercially available silicalite-1 and ZSM-5 have a high affinity and uptake of volatile odors like ethanethiol and propanethiol, also in the presence of water. The simulations showed that propanethiol has a higher affinity, up to 16%, to the two zeolites compared with ethanethiol. Highly flexible and strong free-standing zeolite-CNF films with an adsorbent loading of 89 w/w% have been produced by Ca-induced gelation and vacuum filtration. The CNF-network controls the strength of the composite films and 100 μm thick zeolite-CNF films with a CNF content of less than 10 vol % displayed a tensile strength approaching 10 MPa. Headspace solid phase microextraction (SPME) coupled to gas chromatography-mass spectroscopy (GC/MS) analysis showed that the CNF-zeolite films can eliminate the volatile thiol-based odors to concentrations below the detection ability of the human olfactory system. Odor removing zeolite-cellulose nanofibril films could enable improved transport and storage of fruits and vegetables rich in odors, for example, onion and the tasty but foul-smelling South-East Asian Durian fruit.

  19. Wettability of Nafion and Nafion/Vulcan carbon composite films.

    PubMed

    Li, Xiaoan; Feng, Fangxia; Zhang, Ke; Ye, Siyu; Kwok, Daniel Y; Birss, Viola

    2012-04-24

    The wettability of the Pt/carbon/Nafion catalyst layer in proton exchange membrane fuel cells is critical to their performance and durability, especially the cathode, as water is needed for the transport of protons to the active sites and is also involved in deleterious Pt nanoparticle dissolution and carbon corrosion. Therefore, the focus of this work has been on the first-time use of the water droplet impacting method to determine the wettability of 100% Nafion films, as a benchmark, and then of Vulcan carbon (VC)/Nafion composite films, both deposited by spin-coating in the Pt-free state. Pure Nafion films, shown by SEM analysis to have a nanochanneled structure, are initially hydrophobic but become hydrophilic as the water droplet spreads, likely due to reorientation of the sulfonic acid groups toward water. The wettability of VC/Nafion composite films depends significantly on the VC/Nafion mass ratios, even though Nafion is believed to be preferentially oriented (sulfonate groups toward VC) in all cases. At low VC contents, a significant water droplet contact angle hysteresis is seen, similar to pure Nafion films, while at higher VC contents (>30%), the films become hydrophobic, also exhibiting superhydrophobicity, with surface roughness playing a significant role. At >80% VC, the surfaces become wettable again as there is insufficient Nafion loading present to fully cover the carbon surface, allowing the calculation of the Nafion:carbon ratio required for a full coverage of carbon by Nafion.

  20. Gelatin-Pectin Composite Films from Polyion Complex Hydrogels

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Composite films from gelatin and low-methoxyl pectin were prepared by either ionic complexation or covalent cross-linking. The ionic interactions between positively charged gelatin and negatively charged pectin produced physically reversible hydrogels. The resultant homogeneous gels had improved mec...

  1. [Characterization of inorganic nano-alundum composite film of polyimide].

    PubMed

    Zhou, Hao-Ran; Zhao, De-Ming; Liu, Xin-Gang; Lin, Fei; Fan, Yong

    2008-03-01

    The key to the study on the regularity about the mechanical, thermology and electricities property of the inorganic nano-mingled organic composition thin film is to understand the incorporated quantity, the particle size and distribution of nano-inorganic matter in the membrane quickly and accurately. In the present paper, the chemical structure, surface morphology and the actual content of nano-Al2O3 of the nano Al2O3-composite film of polyimide were characterized by X-ray atomic fluorescent spectroscopy (XRF), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and atomic forced microscope (AFM). The results are that the organic phase of PI and the inorganic phase of Al2O3 formed a complex composite hybrid system of bond-to-bond pattern, the nano-Al2O3 particles in the film of PI are dispersed homogeneously, and the diameter of the particle is smaller than 50 nm; the weight content of Al2O3 is 7.9% by XRF. The approach we used is an effective way of analyzing the inorganic component of the organic composite film materials doped with the inorganic nano-phase materials with the merits of no pretreatment, no fed charge (for analysis of insulation materials), no-contagion, no destruction, high speed and high accuracy, etc. PMID:18536449

  2. Fabrication and Characterization of Amorphous/Nanocrystalline Thin Film Composite

    NASA Astrophysics Data System (ADS)

    Newton, Benjamin S.

    Combining the absorption abilities of amorphous silicon and the electron transport capabilities of crystalline silicon would be a great advantage to not only solar cells but other semiconductor devices. In this work composite films were created using molecular beam epitaxy and electron beam deposition interchangeably as a method to create metallic precursors. Aluminum induced crystallization techniques were used to convert an amorphous silicon film with a capping layer of aluminum nanodots into a film composed of a mixture of amorphous silicon and nanocrystalline silicon. This layer was grown into the amorphous layer by cannibalizing a portion of the amorphous silicon material during the aluminum induced crystallization. Characterization was performed on films and metallic precursors utilizing SEM, TEM, ellipsometry and spectrophotometer.

  3. Action of colloidal silica films on different nano-composites

    NASA Astrophysics Data System (ADS)

    Abdalla, S.; Al-Marzouki, F.; Obaid, A.; Gamal, S.

    Nano-composite films have been the subject of extensive work to develop the energy-storage efficiency of electrostatic capacitors. Factors such as polymer purity, nano-particles size, and film morphology drastically affect the electrostatic efficiency of the dielectric material that form an insulating film between conductive electrodes of a capacitor. This in turn affects the energy storage performance of the capacitor. In the present work, we have studied the dielectric properties of 4 high pure amorphous polymer films: polymethylmethacrylate (PMMA), polystyrene, polyimide and poly-4-vinylpyridine. Comparison between the dielectric properties of these polymers has revealed that the higher break down performance is a character of polyimide PI and PMMA. Also, our experimental data shows that adding colloidal silica to PMMA and PI leads to a net decrease in the dielectric properties compared to the pure polymer.

  4. Polyaniline nanofilms as a monitoring label and dosimetric device for gamma radiation

    SciTech Connect

    Laranjeira, J.M.G.; Khoury, H.J.; Azevedo, W.M. de; Vasconcelos, E.A. de; Silva, E.F. da

    2003-03-15

    In this work, an optical dosimeter for gamma radiation ({sup 60}Co) based on the color change of polyaniline nanofilms in the emeraldine oxidation state was developed by spin coating of the polymer films on glass substrates. After irradiation, the nanofilms were characterized by UV-visible (UV-Vis) absorption spectroscopy as a function of the {sup 60}Co radiation dose. The deep blue color, characteristic of undoped polyaniline films before irradiation subsequently becomes green as the film is irradiated, and the film absorption coefficient exhibits a linear dependence with logarithm of the irradiation dose from 1 to 10 kGy. These results strongly suggest that polyaniline nanofilms can be used as a qualitative and quantitative dosimeter for gamma radiation in the analyzed dose range.

  5. Conducting polyaniline nanowire electrode junction

    NASA Astrophysics Data System (ADS)

    Gaikwad, Sumedh; Bodkhe, Gajanan; Deshmukh, Megha; Patil, Harshada; Rushi, Arti; Shirsat, Mahendra D.; Koinkar, Pankaj; Kim, Yun-Hae; Mulchandani, Ashok

    2015-03-01

    In this paper, a synthesis of conducting polyaniline nanowires electrode junction (CPNEJ) has been reported. Conducting polyaniline nanowires electrode junction on Si/SiO2 substrate (having 3 μm gap between two gold microelectrodes) is prepared. Polyaniline nanowires with diameter (ca. 140 nm to 160 nm) were synthesized by one step electrochemical polymerization using galvanostatic (constant current) technique to bridge this gap. The surface morphology of CPNEJ was studied by scanning electron microscope (SEM). The synthesized CPNEJ is an excellent platform for biosensor applications.

  6. Stabilization of polyaniline solutions through additives

    DOEpatents

    Wrobleski, Debra A.; Benicewicz, Brian C.

    1996-01-01

    A stabilized non-conductive polyaniline solution comprising from about 1 to bout 10 percent by weight polyaniline or a polyaniline derivative, from about 90 to about 99 percent by weight N-methylpyrrolidone, and from about 0.5 percent by weight to about 15 percent by weight of a solution stabilizing additive selected from the group consisting of hindered amine light stabilizers, polymeric amines, and dialkylamines, percent by weight of additive based on the total weight of polyaniline or polyaniline derivative is provided together with a method for stabilizing a polyaniline solution.

  7. Stabilization of polyaniline solutions through additives

    SciTech Connect

    Wrobleski, D.A.; Benicewicz, B.C.

    1996-12-10

    A stabilized non-conductive polyaniline solution comprising from about 1 to about 10 percent by weight polyaniline or a polyaniline derivative, from about 90 to about 99 percent by weight N-methylpyrrolidone, and from about 0.5 percent by weight to about 15 percent by weight of a solution stabilizing additive selected from the group consisting of hindered amine light stabilizers, polymeric amines, and dialkylamines, percent by weight of additive based on the total weight of polyaniline or polyaniline derivative is provided together with a method for stabilizing a polyaniline solution. 4 figs.

  8. Electrochemical formation of Au clusters in polyaniline

    SciTech Connect

    Hatchett, D.W.; Josowicz, M.; Janata, J.; Baer, D.R.

    1999-10-01

    The reduction of chloroaurate and the incorporation of Au clusters in polyaniline, PANI, films have been investigated. The chloroaurate complex is generated at the electrode surface during Cl{sup {minus}} doping of Au/PANI. FTIE and UV/vis data indicate that chloroaurate interacts with PANI and that its reduction to metallic Au occurs preferentially at the nitrogen linkages. The voltammetric and XPS results show that the uptake of both protons and anions is suppressed by the formation of Au clusters due to this interaction. The ability to reduce chloroaurate in PANI films is also demonstrated for Pt electrodes coated with PANI in solutions containing KAuCl{sub 4}. The preliminary results indicate that Au cluster size distribution remains fairly constant regardless of the method used.

  9. Special Polymer/Carbon Composite Films for Detecting SO2

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

    A family of polymer/carbon films has been developed for use as sensory films in electronic noses for detecting SO2 gas at concentrations as low as 1 part per million (ppm). Most previously reported SO2 sensors cannot detect SO2 at concentrations below tens of ppm; only a few can detect SO2 at 1 ppm. Most of the sensory materials used in those sensors (especially inorganic ones that include solid oxide electrolytes, metal oxides, and cadmium sulfide) must be used under relatively harsh conditions that include operation and regeneration at temperatures greater than 100 C. In contrast, the present films can be used to detect 1 ppm of SO2 at typical opening temperatures between 28 and 32 C and can be regenerated at temperatures between 36 and 40 C. The basic concept of making sensing films from polymer/carbon composites is not new. The novelty of the present family of polymer/carbon composites lies in formulating the polymer components of these composites specifically to optimize their properties for detecting SO2. First-principles quantum-mechanical calculations of the energies of binding of SO2 molecules to various polymer functionalities are used as a guide for selecting polymers and understanding the role of polymer functionalities in sensing. The polymer used in the polymer-carbon composite is a copolymer of styrene derivative units with vinyl pyridine or substituted vinyl pyridine derivative units. To make a substituted vinyl pyridine for use in synthesizing such a polymer, poly(2-vinyl pyridine) that has been dissolved in methanol is reacted with 3-chloropropylamine that has been dissolved in a solution of methanol. The methanol is then removed to obtain the copolymer. Later, the copolymer can be dissolved in an appropriate solvent with a suspension of carbon black to obtain a mixture that can be cast and then dried to obtain a sensory film.

  10. Enhanced Field Emission From The Gold- Polyaniline (Au-PANI) Nanocomposite

    SciTech Connect

    Patil, Sandip S.; More, Mahendra A.; Koiry, Shankar P.; Aswal, D. K.

    2010-12-01

    The gold-polyaniline nanocomposite was synthesized by electrochemical route in two steps. In the first step polyaniline film was deposited by cyclic voltammetry on the ITO coated glass substrate, and then synthesis of gold-polyaniline nanocomposite via chronoamperometry. The synthesized gold-polyaniline nanocomposite film was characterized using scanning electron microscope (SEM), X-ray diffraction (XRD), Ultra-violet spectroscopy (UV-vis) and Fourier Transform Infrared Spectrometry (FTIR). The SEM analysis shows well adherent gold nanoparticles on the surface of polyaniline nanofibers. The XRD and UV-Vis spectra indicate formation of gold nanoparticles. From the field emission studies, the value of the turn on field, corresponding to 1 nA emission current, is found to be 0.65 V/{mu}m and emission current density of 1 {mu}A/cm{sup 2} has been drawn at an applied field of 1.1 V/{mu}m. These values are observed to be superior than the reported ones. The field emission current stability investigated at 1 {mu}A over duration of more than four hours is found to be good. The observed field emission characteristics suggest the gold polyaniline nanocomposite as promising material for field emission based applications.

  11. High performance thin-film composite forward osmosis membrane.

    PubMed

    Yip, Ngai Yin; Tiraferri, Alberto; Phillip, William A; Schiffman, Jessica D; Elimelech, Menachem

    2010-05-15

    Recent studies show that osmotically driven membrane processes may be a viable technology for desalination, water and wastewater treatment, and power generation. However, the absence of a membrane designed for such processes is a significant obstacle hindering further advancements of this technology. This work presents the development of a high performance thin-film composite membrane for forward osmosis applications. The membrane consists of a selective polyamide active layer formed by interfacial polymerization on top of a polysulfone support layer fabricated by phase separation onto a thin (40 mum) polyester nonwoven fabric. By careful selection of the polysulfone casting solution (i.e., polymer concentration and solvent composition) and tailoring the casting process, we produced a support layer with a mix of finger-like and sponge-like morphologies that give significantly enhanced membrane performance. The structure and performance of the new thin-film composite forward osmosis membrane are compared with those of commercial membranes. Using a 1.5 M NaCl draw solution and a pure water feed, the fabricated membranes produced water fluxes exceeding 18 L m(2-)h(-1), while consistently maintaining observed salt rejection greater than 97%. The high water flux of the fabricated thin-film composite forward osmosis membranes was directly related to the thickness, porosity, tortuosity, and pore structure of the polysulfone support layer. Furthermore, membrane performance did not degrade after prolonged exposure to an ammonium bicarbonate draw solution.

  12. Latex-like water-borne polyaniline for coating applications

    SciTech Connect

    Liu, H.; Clark, R.; Yang, S.C.

    1998-07-01

    The authors report the synthesis of a polymeric complex of polyaniline that is dispersed in water as a stable suspension. The polymer, PAN:PVME-MLA, is a molecular complex of polyaniline and poly(vinylmethylether-co-maleic acid). The synthetic process leads to a stable latex-like suspension in water. The water-borne conducting polymer, once dried as a thin film on a substrate, is not dissolvable by water or other solvents. An example of piece-dyeing process is presented to show its potential for electrostatic dissipation of textile products. Another example illustrates that the material may be used as electroactive thin-films for electrochromic windows and for rechargeable battery applications.

  13. Study of polyaniline coated CuFe2O4 nanoparticles and their application in biosensor

    NASA Astrophysics Data System (ADS)

    Sharma, Uma Shankar; Shah, Rashmi

    2016-05-01

    Polyaniline coated with nanoferrite particles has attractive application in enzyme less biosensor. In this paper, we have reported the synthesis of copper ferrite by Chemical Coprecipitation method and polymerization of polyaniline by oxidation method. The polyaniline-ferrite composite was characterized by different techniques such as XRD and VSM. The XRD pattern confirmed the presence of cubic phase and particles size in nano scale. The magnetic properties were studied by vibrating sample magnetometer (VSM) technique at room temperature. The higher values of saturation magnetization attributed to the cation distribution change from normal to spinel structure. Some Fe3+ ions drifted from octahedral site to tetrahedral site through the conversion of some Fe2+ ions to Fe3+ ions with super-exchange interactions and gives rise to saturation magnetization. The saturation magnetization of polyaniline coated CuFe2O4 using ammonium nitrate is much less than by polyaniline coated CuFe2O4 using ammonium peroxidisulphate. The saturation magnetization Ms of the nanocomposite is dependent on the volume fraction of the magnetic ferrite particles and on the contribution of the non-magnetic polyaniline coated layer. Polyaniline worked as an immobilization layer in the enzyme less biosensor because enzyme less biosensor is not affected by environmental factor.

  14. Time-resolved thermal transport in compositionally modulated metal films

    SciTech Connect

    Clemens, B.M.; Eesley, G.L.; Paddock, C.A.

    1988-01-15

    We report on investigations of one-dimensional thermal transport in compositionally modulated metal films produced with a systematic variation in atomic lattice mismatch. In the case of Ni-Cu, Ni-Mo, Ni-Ti, and Ni-Zr, we observe the relative effects of interfacial disorder on thermal diffusion. Our observations demonstrate the thermal impedance of a single metal-metal interface and indicate that thermal diffusion in a bilayer film is strongly influenced by the interface between contacting metal pairs. This study is made possible by picosecond time-resolved thermoreflectance measurements which probe thermal transport perpendicular to the film plane. This technique can impact on our understanding of electron scattering and transport across metallic boundaries, and it provides a means of inferring electrical transport properties.

  15. Preparation of nanosize polyaniline and its utilization for microwave absorber.

    PubMed

    Abbas, S M; Dixit, A K; Chatterjee, R; Goel, T C

    2007-06-01

    Polyaniline powder in nanosize has been synthesized by chemical oxidative route. XRD, FTIR, and TEM were used to characterize the polyaniline powder. Crytallite size was estimated from XRD profile and also ascertained by TEM in the range of 15 to 20 nm. The composite absorbers have been prepared by mixing different ratios of polyaniline into procured polyurethane (PU) binder. The complex permittivity (epsilon' - jepsilon") and complex permeability (mu' - jmu") were measured in X-band (8.2-12.4 GHz) using Agilent network analyzer (model PNA E8364B) and its software module 85071 (version 'E'). Measured values of these parameters were used to determine the reflection loss at different frequencies and sample thicknesses, based on a model of a single layered plane wave absorber backed by a perfect conductor. An optimized polyaniline/PU ratio of 3:1 has given a minimum reflection loss of -30 dB (99.9% power absorption) at the central frequency 10 GHz and the bandwidth (full width at half minimum) of 4.2 GHz over whole X-band (8.2 to 12.4 GHz) in a sample thickness of 3.0 mm. The prepared composites can be fruitfully utilized for suppression of electromagnetic interference (EMI) and reduction of radar signatures (stealth technology).

  16. Thin film composition with biological substance and method of making

    DOEpatents

    Campbell, Allison A.; Song, Lin

    1999-01-01

    The invention provides a thin-film composition comprising an underlying substrate of a first material including a plurality of attachment sites; a plurality of functional groups chemically attached to the attachment sites of the underlying substrate; and a thin film of a second material deposited onto the attachment sites of the underlying substrate, and a biologically active substance deposited with the thin-film. Preferably the functional groups are attached to a self assembling monolayer attached to the underlying substrate. Preferred functional groups attached to the underlying substrate are chosen from the group consisting of carboxylates, sulfonates, phosphates, optionally substituted, linear or cyclo, alkyl, alkene, alkyne, aryl, alkylaryl, amine, hydroxyl, thiol, silyl, phosphoryl, cyano, metallocenyl, carbonyl, and polyphosphate. Preferred materials for the underlying substrate are selected from the group consisting of a metal, a metal alloy, a plastic, a polymer, a proteic film, a membrane, a glass or a ceramic. The second material is selected from the group consisting of inorganic crystalline structures, inorganic amorphus structures, organic crystalline structures, and organic amorphus structures. Preferred second materials are phosphates, especially calcium phosphates and most particularly calcium apatite. The biologically active molecule is a protein, peptide, DNA segment, RNA segment, nucleotide, polynucleotide, nucleoside, antibiotic, antimicrobal, radioisotope, chelated radioisotope, chelated metal, metal salt, anti-inflamatory, steriod, nonsteriod anti-inflammatory, analgesic, antihistamine, receptor binding agent, or chemotherapeutic agent, or other biologically active material. Preferably the biologically active molecule is an osteogenic factor the compositions listed above.

  17. Electrophoretic deposition of tannic acid-polypyrrolidone films and composites.

    PubMed

    Luo, Dan; Zhang, Tianshi; Zhitomirsky, Igor

    2016-05-01

    Thin films of polyvinylpyrrolidone (PVP)-tannic acid (TA) complexes were prepared by a conceptually new strategy, based on electrophoretic deposition (EPD). Proof of concept investigations involved the analysis of the deposition yield, FTIR and UV-vis spectroscopy of the deposited material, and electron microscopy studies. The analysis of the deposition mechanism indicated that the limitations of the EPD in the deposition of small phenolic molecules, such as TA, and electrically neutral polymers, similar to PVP, containing hydrogen-accepting carbonyl groups, can be avoided. The remarkable adsorption properties of TA and film forming properties of the PVP-TA complexes allowed for the EPD of materials of different types, such as huntite mineral platelets and hydrotalcite clay particles, TiO2 and MnO2 oxide nanoparticles, multiwalled carbon nanotubes, TiN and Pd nanoparticles. Moreover, PVP-TA complexes were used for the co-deposition of different materials and formation of composite films. In another approach, TA was used as a capping agent for the hydrothermal synthesis of ZnO nanorods, which were then deposited by EPD using PVP-TA complexes. The fundamental adsorption and interaction mechanisms of TA involved chelation of metal atoms on particle surfaces with galloyl groups, π-π interactions and hydrogen bonding. The films prepared by EPD can be used for various applications, utilizing functional properties of TA, PVP, inorganic and organic materials of different types and their composites.

  18. Electrophoretic deposition of tannic acid-polypyrrolidone films and composites.

    PubMed

    Luo, Dan; Zhang, Tianshi; Zhitomirsky, Igor

    2016-05-01

    Thin films of polyvinylpyrrolidone (PVP)-tannic acid (TA) complexes were prepared by a conceptually new strategy, based on electrophoretic deposition (EPD). Proof of concept investigations involved the analysis of the deposition yield, FTIR and UV-vis spectroscopy of the deposited material, and electron microscopy studies. The analysis of the deposition mechanism indicated that the limitations of the EPD in the deposition of small phenolic molecules, such as TA, and electrically neutral polymers, similar to PVP, containing hydrogen-accepting carbonyl groups, can be avoided. The remarkable adsorption properties of TA and film forming properties of the PVP-TA complexes allowed for the EPD of materials of different types, such as huntite mineral platelets and hydrotalcite clay particles, TiO2 and MnO2 oxide nanoparticles, multiwalled carbon nanotubes, TiN and Pd nanoparticles. Moreover, PVP-TA complexes were used for the co-deposition of different materials and formation of composite films. In another approach, TA was used as a capping agent for the hydrothermal synthesis of ZnO nanorods, which were then deposited by EPD using PVP-TA complexes. The fundamental adsorption and interaction mechanisms of TA involved chelation of metal atoms on particle surfaces with galloyl groups, π-π interactions and hydrogen bonding. The films prepared by EPD can be used for various applications, utilizing functional properties of TA, PVP, inorganic and organic materials of different types and their composites. PMID:26878711

  19. Ambient-Temperature Sputtering Of Composite Oxide Films

    NASA Technical Reports Server (NTRS)

    Thakoor, Sarita

    1992-01-01

    Technique for deposition of homogeneous films of multicomponent oxides on substrates at ambient temperature based on sequential sputter deposition of individual metal components, as alternating ultra-thin layers, from multiple targets. Substrates rotated over sputtering targets of lead, zirconium, and titanium. Dc-magnetron sputtering of constituent metals in reactive ambient of argon and oxygen leads to formation of the respective metal oxides intermixed on extremely fine scale in desired composition. Compatible with low-temperature microelectronic processing.

  20. Aerosol-assisted chemical vapor deposition (AACVD) of binary alloy films: Studies of film composition

    SciTech Connect

    Xu, C.; Hampden-Smith, M.J.; Kodas, T.T.

    1995-08-01

    The chemical vapor deposition (CVD) of Cu-Ag and Cu-Pd alloys using aerosol precursor delivery over a range of preheating temperatures, 70 {approximately} 80 C and substrate temperatures, 250 {approximately} 300 C is described. The precursors used include Cu(hfac){sub 2}, (hfac)Ag(SEt{sub 2}) and Pd(hfac){sub 2} dissolved in toluene and 10% H{sub 2} in Ar as carrier gas. The films were characterized by SEM, EDS and X-ray diffraction (XRD). The X-ray diffraction results showed the Cu/Ag films were composed of {alpha}- and {beta}-phases of Cu-Ag alloys, the Cu/Pd films were Cu-Pd and Pd-Ag alloy, solid solutions, under these conditions. Compositional variation studies in Cu-Pd and Pd-Ag alloy systems were also conducted by mixing Cu(hfac){sub 2}/Pd(hfac){sub 2} and (hfac) Ag(SEt{sub 2})/Pd(hfac){sub 2} in toluene solution in different ratios. The films were characterized by X-ray diffraction and the results showed the composition of films was affected by the solution stoichiometry.

  1. Electromagnetic radiation absorbers and modulators comprising polyaniline

    DOEpatents

    Epstein, Arthur J.; Ginder, John M.; Roe, Mitchell G.; Hajiseyedjavadi, Hamid

    1992-01-01

    A composition for absorbing electromagnetic radiation, wherein said electromagnetic radiation possesses a wavelength generally in the range of from about 1000 Angstroms to about 50 meters, wherein said composition comprises a polyaniline composition of the formula ##STR1## where y can be equal to or greater than zero, and R.sup.1 and R.sup.2 are independently selected from the group containing of H, --OCH.sub.3, --CH.sub.3, --F, --Cl, --Br, --I, NR.sup.3 .sub.2, --NHCOR.sup.3, --OH, --O.sup.-, SR.sup.3, --OCOR.sup.3, --NO.sub.2, --COOH, --COOR.sup.3, --COR.sup.3, --CHO, and --CN, where R.sup.3 is a C.sub.1 to C.sub.8 alkyl, aryl or aralkyl group.

  2. Film/Adhesive Processing Module for Fiber-Placement Processing of Composites

    NASA Technical Reports Server (NTRS)

    Hulcher, A. Bruce

    2007-01-01

    An automated apparatus has been designed and constructed that enables the automated lay-up of composite structures incorporating films, foils, and adhesives during the automated fiber-placement process. This apparatus, denoted a film module, could be used to deposit materials in film or thin sheet form either simultaneously when laying down the fiber composite article or in an independent step.

  3. One-step synthesis of magnetic chitosan polymer composite films

    NASA Astrophysics Data System (ADS)

    Cesano, Federico; Fenoglio, Gaia; Carlos, Luciano; Nisticò, Roberto

    2015-08-01

    In this study, a magnetic iron oxide-chitosan composite film is synthesized by one-step method and thoroughly investigated in order to better understand its inorganic/organic properties. A deep physico-chemical characterization of the magnetic films has been performed. In particular, the material composition was evaluated by means of XRD and ATR-FTIR spectroscopy, whereas the thermal stability and the subsequent inorganic phase transitions involving iron oxide species were followed by TGA analyses carried out at different experimental conditions (i.e. inert and oxidative atmosphere). The magnetic properties of the films were tested at the bulk and at the surface level, performing respectively magnetization hysteresis curve and magnetic force microscopy (MFM) surface mapping. Results indicate that the synthesized material can be prepared through a very simple synthetic procedure and suggests that it can be successfully applied for instance to environmental applications, such as the adsorption of contaminants from solid and liquid media thanks to its pronounced magnetic properties, which favour its recover.

  4. Polyaniline-modified 3D-flower-like molybdenum disulfide composite for efficient adsorption/photocatalytic reduction of Cr(VI).

    PubMed

    Gao, Yang; Chen, Changlun; Tan, Xiaoli; Xu, Huan; Zhu, Kairuo

    2016-08-15

    Polyaniline (PANI) was modified onto 3D flower-like molybdenum disulfide (MoS2) to prepare a novel organic-inorganic hybrid material, PANI@MoS2. PANI@MoS2 was characterized by scanning and transmission electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction and thermogravimetric analysis. The results indicate that PANI was modified onto MoS2. PANI@MoS2 was applied as an adsorbent to remove Cr(VI) from aqueous solutions, and the adsorption isotherms fit well to the Langmuir model; the maximum removal capacity of Cr(VI) by PANI@MoS2 was 526.3 and 623.2mg/g at pH 3.0 and 1.5, respectively. PANI@MoS2 exhibited an enhanced removal capacity of Cr(VI) in comparison with bare MoS2 and other adsorbents. The adsorption of Cr(VI) on PANI@MoS2 might be attributed to the complexation between the amine and imine groups on the surface of PANI@MoS2 with Cr(VI). This study implies that the hybrid material PANI@MoS2 is a potential adsorbent for Cr(VI) removal from large volumes of aqueous solutions.

  5. Photoactive composite films prepared from mixtures of polystyrene microgel dispersions and poly(3-hexylthiophene) solutions.

    PubMed

    Chen, Mu; Cui, Zhengxing; Edmondson, Steve; Hodson, Nigel; Zhou, Mi; Yan, Junfeng; O'Brien, Paul; Saunders, Brian R

    2015-11-14

    Whilst polystyrene microgels belong to the oldest family of microgel particles, their behaviours when deposited onto substrates or prepared as composites have received little attention. Because polystyrene microgels are solvent-swellable, and inherently colloidally stable, they are well suited to form composites with conjugated polymers. Here, we investigate the morphology and light absorption properties of spin coated composite films prepared from mixed dispersions of polystyrene microgels and poly(3-hexylthiophene) (P3HT) for the first time. We compare the morphologies of the composite films to spin coated microgel films. The films were studied using optical microscopy, SEM, AFM, wide-angle X-ray diffraction and UV-visible spectroscopy. The films contained flattened microgel particles with an aspect ratio of ∼10. Microgel islands containing hexagonally close packed particles were evident for both the pure microgel and microgel/P3HT composite films. The latter were electrically conducting. The composite film morphology was dependent on the microgel and P3HT concentration used for film preparation and a morphology phase diagram was constructed. The P3HT phase acted as an electrically conducting cement and increased the robustness of the films to solvent washing. The composite films were photoactive due to the P3HT component. The absorbance for the films was tuneable and increased linearly with both microgel and P3HT concentration. The results of the study should apply to other organic swellable microgel/conjugated polymer combinations and may lead to new colloidal composites for future optoelectronic applications.

  6. Development and physicochemical characterization of alginate composite film loaded with simvastatin as a potential wound dressing.

    PubMed

    Rezvanian, Masoud; Amin, Mohd Cairul Iqbal Mohd; Ng, Shiow-Fern

    2016-02-10

    Previously, studies have demonstrated that topical application of simvastatin can promote wound healing in diabetic mice via augmentation of angiogenesis and lymphangiogenesis. This study aimed to formulate and characterize simvastatin in alginate-based composite film wound dressings. Biopolymers used for composite films were sodium alginate blended with pectin or gelatin. The films were prepared and characterized based on their physical properties, surface morphology, mechanical strength and rheology. Then, in vitro drug releases from the films were investigated and, finally, the cell viability assay was performed to assess the cytotoxicity profile. From the pre-formulation studies, alginate/pectin composite film showed to possess desirable wound dressing properties and superior mechanical properties. The in vitro drug release profile revealed that alginate/pectin film produced a controlled release drug profile, and cell viability assay showed that the film was non-toxic. In summary, alginate/pectin composite film is suitable to be formulated with simvastatin as a potential wound dressing.

  7. Combinatorial thin film composition mapping using three dimensional deposition profiles

    NASA Astrophysics Data System (ADS)

    Suram, Santosh K.; Zhou, Lan; Becerra-Stasiewicz, Natalie; Kan, Kevin; Jones, Ryan J. R.; Kendrick, Brian M.; Gregoire, John M.

    2015-03-01

    Many next-generation technologies are limited by material performance, leading to increased interest in the discovery of advanced materials using combinatorial synthesis, characterization, and screening. Several combinatorial synthesis techniques, such as solution based methods, advanced manufacturing, and physical vapor deposition, are currently being employed for various applications. In particular, combinatorial magnetron sputtering is a versatile technique that provides synthesis of high-quality thin film composition libraries. Spatially addressing the composition of these thin films generally requires elemental quantification measurements using techniques such as energy-dispersive X-ray spectroscopy or X-ray fluorescence spectroscopy. Since these measurements are performed ex-situ and post-deposition, they are unable to provide real-time design of experiments, a capability that is required for rapid synthesis of a specific composition library. By using three quartz crystal monitors attached to a stage with translational and rotational degrees of freedom, we measure three-dimensional deposition profiles of deposition sources whose tilt with respect to the substrate is robotically controlled. We exhibit the utility of deposition profiles and tilt control to optimize the deposition geometry for specific combinatorial synthesis experiments.

  8. Two kinds of composite films: Graphene oxide/carbon nanotube film and graphene oxide/activated carbon film via a self-assemble preparation process

    NASA Astrophysics Data System (ADS)

    Zou, Li-feng; Ma, Nan; Sun, Mei; Ji, Tian-hao

    2014-11-01

    Two kinds of free-standing composite films, including graphene oxide and activated carbon film as well as graphene oxide and carbon nanotube film, were fabricated through a simple suspension mixing and then natural deposition process. The films were characterized by various measurement techniques in detail. The results show that the composite films without any treatment almost still remain the original properties of the corresponding precursors, and exhibit loose structure, which can be easily broken in water; whereas after treated at 200 °C in air, the films become relatively more dense, and even if immersed into concentrated strong alkali or acid for five days, they still keep the film-morphologies, but regretfully, they show obvious brittleness and slight hydrophilicity. As soon as the treated films are performed in high concentrated strong alkali for about one day, their brittleness and wettability can be improved and became good flexibility and complete hydrophilicity.

  9. Simultaneous determination of polar and apolar compounds in environmental samples by a polyaniline/hydroxyl multi-walled carbon nanotubes composite-coated stir bar sorptive extraction coupled with high performance liquid chromatography.

    PubMed

    Hu, Cong; He, Man; Chen, Beibei; Hu, Bin

    2015-05-15

    Developing novel coatings for stir bar sorptive extraction (SBSE) is essential for extending the application of SBSE. Herein, a polyaniline/hydroxyl multi-walled carbon nanotubes (PANi/MWCNTs-OH) composite-coated stir bar was prepared via the adhesion technique for the simultaneous extraction of polar and apolar compounds, and a novel method of PANi/MWCNTs-OH-coated SBSE coupled with high performance liquid chromatography-ultraviolet detection (HPLC-UV) was proposed. To test the extraction performance of PANi/MWCNTs-OH-coated stir bar, phenols, non-steroidal anti-inflammatory drugs, and polychlorinated biphenyls were selected as representatives for polar, semi-polar and apolar compounds, respectively. High enrichment factors (EFs) ranged from 20.4 to 60.4-fold (theoretical EF, 100-fold) for target analytes were achieved, indicating that the proposed method is applicable in simultaneous analysis of the compounds with different polarities. The prepared PANi/MWCNTs-OH-coated stir bar has a good preparation reproducibility and can be reused for 20 times. The limits of detection (LODs, S/N=3) were found to be in the range of 0.09-0.81μg/L. To validate the applicability, the proposed method was successfully applied to the analysis of eight target analytes in Yangtze River water after filtration and in the extract from sediment samples.

  10. Determination of trace/ultratrace rare earth elements in environmental samples by ICP-MS after magnetic solid phase extraction with Fe3O4@SiO2@polyaniline-graphene oxide composite.

    PubMed

    Su, Shaowei; Chen, Beibei; He, Man; Hu, Bin; Xiao, Zuowei

    2014-02-01

    A novel Fe3O4@SiO2@polyaniline-graphene oxide composite (MPANI-GO) was prepared through a simple noncovalent method and applied to magnetic solid phase extraction (MSPE) of trace rare earth elements (REEs) in tea leaves and environmental water samples followed by inductively coupled plasma mass spectrometry (ICP-MS) detection. The prepared MPANI-GO was characterized by transmission electron microscopy and vibrating sample magnetometer. Various parameters affecting MPANI-GO MSPE of REEs have been investigated. Under the optimized conditions, the limits of detection (LODs, 3σ) for REEs were in the range of 0.04-1.49 ng L(-1) and the relative standard deviations (RSDs, c=20 ng L(-1), n=7) were 1.7-6.5%. The accuracy of the proposed method was validated by analyzing a Certified Reference Material of GBW 07605 tea leaves. The method was also successfully applied for the determination of trace REEs in tea leaves and environmental water samples. The developed MPANI-GO MSPE-ICP-MS method has the advantages of simplicity, rapidity, high sensitivity, high enrichment factor and is suitable for the analysis of trace REEs in samples with complex matrix.

  11. Transparent megahertz circuits from solution-processed composite thin films

    NASA Astrophysics Data System (ADS)

    Liu, Xingqiang; Wan, Da; Wu, Yun; Xiao, Xiangheng; Guo, Shishang; Jiang, Changzhong; Li, Jinchai; Chen, Tangsheng; Duan, Xiangfeng; Fan, Zhiyong; Liao, Lei

    2016-04-01

    Solution-processed amorphous oxide semiconductors have attracted considerable interest in large-area transparent electronics. However, due to its relative low carrier mobility (~10 cm2 V-1 s-1), the demonstrated circuit performance has been limited to 800 kHz or less. Herein, we report solution-processed high-speed thin-film transistors (TFTs) and integrated circuits with an operation frequency beyond the megahertz region on 4 inch glass. The TFTs can be fabricated from an amorphous indium gallium zinc oxide/single-walled carbon nanotube (a-IGZO/SWNT) composite thin film with high yield and high carrier mobility of >70 cm2 V-1 s-1. On-chip microwave measurements demonstrate that these TFTs can deliver an unprecedented operation frequency in solution-processed semiconductors, including an extrinsic cut-off frequency (fT = 102 MHz) and a maximum oscillation frequency (fmax = 122 MHz). Ring oscillators further demonstrated an oscillation frequency of 4.13 MHz, for the first time, realizing megahertz circuit operation from solution-processed semiconductors. Our studies represent an important step toward high-speed solution-processed thin film electronics.Solution-processed amorphous oxide semiconductors have attracted considerable interest in large-area transparent electronics. However, due to its relative low carrier mobility (~10 cm2 V-1 s-1), the demonstrated circuit performance has been limited to 800 kHz or less. Herein, we report solution-processed high-speed thin-film transistors (TFTs) and integrated circuits with an operation frequency beyond the megahertz region on 4 inch glass. The TFTs can be fabricated from an amorphous indium gallium zinc oxide/single-walled carbon nanotube (a-IGZO/SWNT) composite thin film with high yield and high carrier mobility of >70 cm2 V-1 s-1. On-chip microwave measurements demonstrate that these TFTs can deliver an unprecedented operation frequency in solution-processed semiconductors, including an extrinsic cut-off frequency (f

  12. Intra-grain conduction of self-doped polyaniline

    NASA Astrophysics Data System (ADS)

    Usami, Yuki; Imamura, Kentaro; Akai, Tomoki; Che, Dock-Chil; Ohoyama, Hiroshi; Kobayashi, Hikaru; Matsumoto, Takuya

    2016-08-01

    The conduction behavior of ultrathin films (about 10 nm thick) composed of self-doped water-soluble polyaniline sulfonate (SPAN) was investigated using nano-gap electrodes under vacuum conditions. The conductance was found to be ohmic even in the high field regime up to 105 V cm-1 over a temperature range of 10-300 K. The temperature dependence of the conductance indicated that SPAN gave the extremely high value of localization length ( L ) = 300 nm without secondary doping, in comparison with conventional polyaniline. We propose that SPAN forms long-range highly crystalline metallic grains, and we observed intra-grain conduction due to some grains directly bridging the two nano-gap electrodes at low temperature. We conclude that inter-grain conduction becomes dominant as the temperature increases.

  13. Superior piezoelectric composite films: taking advantage of carbon nanomaterials.

    PubMed

    Saber, Nasser; Araby, Sherif; Meng, Qingshi; Hsu, Hung-Yao; Yan, Cheng; Azari, Sara; Lee, Sang-Heon; Xu, Yanan; Ma, Jun; Yu, Sirong

    2014-01-31

    Piezoelectric composites comprising an active phase of ferroelectric ceramic and a polymer matrix have recently found numerous sensory applications. However, it remains a major challenge to further improve their electromechanical response for advanced applications such as precision control and monitoring systems. We here investigated the incorporation of graphene platelets (GnPs) and multi-walled carbon nanotubes (MWNTs), each with various weight fractions, into PZT (lead zirconate titanate)/epoxy composites to produce three-phase nanocomposites. The nanocomposite films show markedly improved piezoelectric coefficients and electromechanical responses (50%) besides an enhancement of ~200% in stiffness. The carbon nanomaterials strengthened the impact of electric field on the PZT particles by appropriately raising the electrical conductivity of the epoxy. GnPs have been proved to be far more promising in improving the poling behavior and dynamic response than MWNTs. The superior dynamic sensitivity of GnP-reinforced composite may be caused by the GnPs' high load transfer efficiency arising from their two-dimensional geometry and good compatibility with the matrix. The reduced acoustic impedance mismatch resulting from the improved thermal conductance may also contribute to the higher sensitivity of GnP-reinforced composite. This research pointed out the potential of employing GnPs to develop highly sensitive piezoelectric composites for sensing applications. PMID:24398819

  14. Neutron reflectivity studies of composite nanoparticle - copolymer thin films

    NASA Astrophysics Data System (ADS)

    Lauter-Pasyuk, V.; Lauter, H. J.; Ausserre, D.; Gallot, Y.; Cabuil, V.; Hamdoun, B.; Kornilov, E. I.

    1998-06-01

    Neutron reflection was used for the investigation of a new class of copolymers - composite materials, consisting of symmetric polystyrene-polybuthylmethacrylate (PS-PBMA) diblock copolymer with incorporated nanoparticles γ-Fe 2O 3 of a few nanometers in diameter. The presence of the nanoparticles induces an elastic distortion of the copolymer matrix. From the experiments we obtained information about the lamellar order of the polymer matrix, the distribution of the nanoparticles in the film and the distortion of the interfaces caused by the nanoparticles.

  15. Electrochemical design of mesoporous Pt-Ru alloy films with various compositions toward superior electrocatalytic performance.

    PubMed

    Wang, Hongjing; Imura, Masataka; Nemoto, Yoshihiro; Wang, Liang; Jeong, Hu Young; Yokoshima, Tokihiko; Terasaki, Osamu; Yamauchi, Yusuke

    2012-10-01

    Mesoporous Pt-Ru alloy films with various compositions were synthesized by electrochemical plating in an aqueous surfactant solution. After the removal of surfactants, continuous mesoporous Pt-Ru alloy films possessing uniform mesopores with diameter about 7 nm were obtained. The Ru content in the films could be controlled from 0 to 13 at % by changing the precursor compositions. For all the films, the mesostructural periodicities and the mesopore sizes in the films were not changed. Due to the mesoporous structure and the doped Ru content, our mesoporous Pt-Ru films showed superior electrocatalytic activity for methanol oxidation reaction in comparison with the commercially available Pt catalyst.

  16. Application of nano-TiO2/LDPE composite film on photocatalytic oxidation degradation of dichloromethane.

    PubMed

    Suwannahong, Kowit; Liengcharernsit, Winai; Sanongraj, Wipada; Kruenate, Jittiporn

    2012-09-01

    This study focused on the photocatalytic destruction of dichloromethane (DCM) in indoor air using the nano-TiO2/LDPE composite film as an economical photocatalyst. The nano-TiO2 was dispersed in a polyethylene matrix to form composite film. The photocatalytic activity of the nano-TiO2/LDPE composite films was evaluated through the degradation of dichloromethane(DCM) under UV-C irradiance at specific wavelength of 254 nm. The percentage of nano-TiO2 contents varied from 0, 5, and 10% (wt cat./wt LDPE composite film). The results derived from the kinetic model revealed that the photocatalytic rates of 5 and 10 wt.% nano-TiO2/ LDPE composite films follow the first order reaction while the rate of the film without TiO2 followed the zero order reaction. At low concentration of DCM, the rate of photocatalytic degradation of the DCM was slower than that at high DCM concentration. The 10 wt.% of TiO2 content of the nano-TiO2/LDPE composite film yielded the highest degradation efficiency of 78%, followed by the removal efficiency of 55% for the 5 wt.% of TiO2 content of the nano-TiO2/LDPE composite film. In contrast with the composite film containing nano-TiO2, the LDPE film without adding nano-TiO2 expressed the degradation efficiency of 28%.

  17. Enhanced electrochemical supercapacitor properties with synergistic effect of polyaniline, graphene and AgxO

    NASA Astrophysics Data System (ADS)

    Usman, Muhammad; Pan, Lujun; Asif, Muhammad; Mahmood, Zafar; Khan, M. A.; Fu, Xin

    2016-05-01

    The graphene-Ag2O/polyaniline (GAP) composite has been synthesized by in-situ polymerization. It has been observed that Ag2O nanoparticles exist on the porous spongy background of PANI (polyaniline). The optimized composition of the synthesized composite exhibits an extraordinary specific capacitance of 1572 Fg-1 at 0.05 Ag-1 current density and good cyclic stability of 85% over 3000 charge-discharge cycles. The extraordinary electrochemical performance indicates the positive synergistic effect of PANI, graphene and Ag2O. The Ag2O nanoparticles might be responsible for improved electrical conductivity, and graphene might contribute in enhancing the electrochemical stability of the PANI electrode.

  18. Transparent megahertz circuits from solution-processed composite thin films.

    PubMed

    Liu, Xingqiang; Wan, Da; Wu, Yun; Xiao, Xiangheng; Guo, Shishang; Jiang, Changzhong; Li, Jinchai; Chen, Tangsheng; Duan, Xiangfeng; Fan, Zhiyong; Liao, Lei

    2016-04-21

    Solution-processed amorphous oxide semiconductors have attracted considerable interest in large-area transparent electronics. However, due to its relative low carrier mobility (∼10 cm(2) V(-1) s(-1)), the demonstrated circuit performance has been limited to 800 kHz or less. Herein, we report solution-processed high-speed thin-film transistors (TFTs) and integrated circuits with an operation frequency beyond the megahertz region on 4 inch glass. The TFTs can be fabricated from an amorphous indium gallium zinc oxide/single-walled carbon nanotube (a-IGZO/SWNT) composite thin film with high yield and high carrier mobility of >70 cm(2) V(-1) s(-1). On-chip microwave measurements demonstrate that these TFTs can deliver an unprecedented operation frequency in solution-processed semiconductors, including an extrinsic cut-off frequency (f(T) = 102 MHz) and a maximum oscillation frequency (f(max) = 122 MHz). Ring oscillators further demonstrated an oscillation frequency of 4.13 MHz, for the first time, realizing megahertz circuit operation from solution-processed semiconductors. Our studies represent an important step toward high-speed solution-processed thin film electronics. PMID:27009830

  19. Characterization of whey protein-carboxymethylated chitosan composite films with and without transglutaminase treatment.

    PubMed

    Jiang, Shu-Juan; Zhang, Xuan; Ma, Ying; Tuo, Yanfeng; Qian, Fang; Fu, Wenjia; Mu, Guangqing

    2016-11-20

    Edible composite packaging has the advantage of complementary functional properties over its each bio-components. However, reports on whey protein concentrates (WPC)-carboxymethylated chitosan (CMC) composite films have not yet been released. To investigate the preparation of WPC-CMC composite films and its functional properties, four types of WPC-CMC composite films were prepared with and without Transglutaminase (TGase) treatment by mixing WPC aqueous solutions (10%, w/v) with CMC aqueous solutions (3%, w/v) at WPC to CMC volume ratios of (100:0), (75:25), (50:50), and (25:75). SDS-PAGE confirmed that TGase catalyzed crosslinking of whey protein. Results revealed that CMC incorporation conferred a smooth and even surface microstructure on the films and markedly improved the transparency, water barrier properties, mechanical properties and solubility of the composite film. Furthermore, TGase resulted in an improvement in the water vapor barrier properties and mechanical properties of WPC-CMC (75:25 and 50:50, v/v) composite films, and there was no impairment of thermal stability of composite films. Therefore, TGase successfully facilitated the formation of WPC-CMC composite films with some improved functional properties. This offers potential applications as an alternative approach to the preparation of edible packaging films.

  20. Characterization of whey protein-carboxymethylated chitosan composite films with and without transglutaminase treatment.

    PubMed

    Jiang, Shu-Juan; Zhang, Xuan; Ma, Ying; Tuo, Yanfeng; Qian, Fang; Fu, Wenjia; Mu, Guangqing

    2016-11-20

    Edible composite packaging has the advantage of complementary functional properties over its each bio-components. However, reports on whey protein concentrates (WPC)-carboxymethylated chitosan (CMC) composite films have not yet been released. To investigate the preparation of WPC-CMC composite films and its functional properties, four types of WPC-CMC composite films were prepared with and without Transglutaminase (TGase) treatment by mixing WPC aqueous solutions (10%, w/v) with CMC aqueous solutions (3%, w/v) at WPC to CMC volume ratios of (100:0), (75:25), (50:50), and (25:75). SDS-PAGE confirmed that TGase catalyzed crosslinking of whey protein. Results revealed that CMC incorporation conferred a smooth and even surface microstructure on the films and markedly improved the transparency, water barrier properties, mechanical properties and solubility of the composite film. Furthermore, TGase resulted in an improvement in the water vapor barrier properties and mechanical properties of WPC-CMC (75:25 and 50:50, v/v) composite films, and there was no impairment of thermal stability of composite films. Therefore, TGase successfully facilitated the formation of WPC-CMC composite films with some improved functional properties. This offers potential applications as an alternative approach to the preparation of edible packaging films. PMID:27561482

  1. Combinatorial Preparation and Ferroelectric Properties of Compositionally Gradient PZT Thin Films

    NASA Astrophysics Data System (ADS)

    He, Gang; Peng, Chao; He, Mingzhong; Hong, Jianhe; Li, Haifeng; Gong, Yansheng

    2013-06-01

    Using a combinatorial synthesis process, compositionally gradient PZT thin films were conveniently prepared by a chemical solution decomposition (CSD) method. The thin films showed a perovskite structure with (111)-preferred orientation and a thickness of around 450 nm. The surface morphology and ferroelectric properties were significantly different, depending on the direction of compositional gradient. The detailed composition and gradient of the composition was seen to affect the property of compositionally gradient PZT thin films. The gradient thin film PZT654, with a Zr:Ti ratio of 6:4 at the bottom of the film nearest to the substrate, and with an total composition around the morphotropic phase boundary (MPB, x = 0.52) showed favorable ferroelectric properties. However, no typical offset of the hysteresis loops was observed in our work.

  2. Silver nanowire composite thin films as transparent electrodes for Cu(In,Ga)Se₂/ZnS thin film solar cells.

    PubMed

    Tan, Xiao-Hui; Chen, Yu; Liu, Ye-Xiang

    2014-05-20

    Solution processed silver nanowire indium-tin oxide nanoparticle (AgNW-ITONP) composite thin films were successfully applied as the transparent electrodes for Cu(In,Ga)Se₂ (CIGS) thin film solar cells with ZnS buffer layers. Properties of the AgNW-ITONP thin film and its effects on performance of CIGS/ZnS thin film solar cells were studied. Compared with the traditional sputtered ITO electrodes, the AgNW-ITONP thin films show comparable optical transmittance and electrical conductivity. Furthermore, the AgNW-ITONP thin film causes no physical damage to the adjacent surface layer and does not need high temperature annealing, which makes it very suitable to use as transparent conductive layers for heat or sputtering damage-sensitive optoelectronic devices. By using AgNW-ITONP electrodes, the required thickness of the ZnS buffer layers for CIGS thin film solar cells was greatly decreased. PMID:24922214

  3. Functional chitosan-based grapefruit seed extract composite films for applications in food packaging technology

    SciTech Connect

    Tan, Y.M.; Lim, S.H.; Tay, B.Y.; Lee, M.W.; Thian, E.S.

    2015-09-15

    Highlights: • Chitosan-based grapefruit seed extract (GFSE) films were solution casted. • GFSE was uniformly dispersed within all chitosan film matrices. • All chitosan-based composite films showed remarkable transparency. • Increasing amounts of GFSE incorporated increased the elongation at break of films. • Chitosan-based GFSE composite films inhibited the proliferation of fungal growth. - Abstract: Chitosan-based composite films with different amounts of grapefruit seed extract (GFSE) (0.5, 1.0 and 1.5% v/v) were fabricated via solution casting technique. Experimental results showed that GFSE was uniformly dispersed within all chitosan film matrices. The presence of GFSE made the films more amorphous and tensile strength decreased, while elongation at break values increased as GFSE content increased. Results from the measurement of light transmission revealed that increasing amounts of GFSE (from 0.5 to 1.5% v/v) did not affect transparency of the films. Furthermore, packaging of bread samples with chitosan-based GFSE composite films inhibited the proliferation of fungal growth as compared to control samples. Hence, chitosan-based GFSE composite films have the potential to be a useful material in the area of food technology.

  4. Antimicrobial activity of nisin incorporated in pectin and polylactic acid composite films against Listeria monocytogenes

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Extruded composite films from 20% pectin and 80% polylactic acids (PLA) were developed and nisin was loaded into films by a diffusion post extrusion. Inhibitory activities of the films against Listeria monocytogenes were evaluated in brain heart infusion (BHI) broth, liquid egg white and orange juic...

  5. Fabrication of transparent and ultraviolet shielding composite films based on graphene oxide and cellulose acetate.

    PubMed

    de Moraes, Ana Carolina Mazarin; Andrade, Patricia Fernanda; de Faria, Andreia Fonseca; Simões, Mateus Batista; Salomão, Francisco Carlos Carneiro Soares; Barros, Eduardo Bedê; Gonçalves, Maria do Carmo; Alves, Oswaldo Luiz

    2015-06-01

    Graphene oxide (GO) has been considered a promising filler material for building polymeric nanocomposites because of its excellent dispersibility and high surface area. In this work, we present the fabrication and characterization of transparent and ultraviolet (UV) shielding composite films based on GO and cellulose acetate (CA). GO sheets were found to be well-dispersed throughout the CA matrix, providing smooth and homogeneous composite films. Moreover, the GO sheets were completely embedded within the CA matrix and no presence of this nanomaterial was found at the surface. Nevertheless, CAGO composite films offered an improved high energy light-shielding capacity when compared to pristine CA films. Particularly for UVC irradiation, the CAGO film containing 0.50wt% GO displayed a UV-shielding capacity of 57%, combined with 79% optical transparency under visible light. These CAGO composite films can be potentially applied as transparent UV-protective coatings for packing biomedical, pharmaceutical, and food products.

  6. Enhanced piezoelectric performance of composite sol-gel thick films evaluated using piezoresponse force microscopy.

    PubMed

    Liu, Yuanming; Lam, Kwok Ho; Kirk Shung, K; Li, Jiangyu; Zhou, Qifa

    2013-05-14

    Conventional composite sol-gel method has been modified to enhance the piezoelectric performance of ceramic thick films. Lead zirconate titanate (PZT) and lead magnesium niobate-lead titanate (PMN-PT) thick films were fabricated using the modified sol-gel method for ultrasonic transducer applications. In this work, piezoresponse force microscopy was employed to evaluate the piezoelectric characteristics of PZT and PMN-PT composite sol-gel thick films. The images of the piezoelectric response and the strain-electric field hysteresis loop behavior were measured. The effective piezoelectric coefficient (d33,eff) of the films was determined from the measured loop data. It was found that the effective local piezoelectric coefficient of both PZT and PMN-PT composite films is comparable to that of their bulk ceramics. The promising results suggest that the modified composite sol-gel method is a promising way to prepare the high-quality, crack-free ceramic thick films. PMID:23798771

  7. Sweat pore mapping using a fluorescein-polymer composite film for fingerprint analysis.

    PubMed

    Pyo, Minkyeong; Lee, Joosub; Baek, Woohyun; Lee, Chan Woo; Park, Bum Jun; Kim, Jong-Man

    2015-02-21

    A simple but efficient sweat pore mapping method based on a fluorescein-PVP composite film was developed for fingerprint analysis. The composite film displays a fluorometric turn-on response upon contact with a small quantity of water secreted from human sweat pores, allowing precise mapping of sweat pores on a fingertip.

  8. A soft approach to encapsulate sulfur: polyaniline nanotubes for lithium-sulfur batteries with long cycle life.

    PubMed

    Xiao, Lifen; Cao, Yuliang; Xiao, Jie; Schwenzer, Birgit; Engelhard, Mark H; Saraf, Laxmikant V; Nie, Zimin; Exarhos, Gregory J; Liu, Jun

    2012-03-01

    A novel vulcanized polyaniline nanotube/sulfur composite was prepared successfully via an in situ vulcanization process by heating a mixture of polyaniline nanotube and sulfur at 280 °C. The electrode could retain a discharge capacity of 837 mAh g(-1) after 100 cycles at a 0.1 C rate and manifested 76% capacity retention up to 500 cycles at a 1 C rate. PMID:22278978

  9. Advanced Synthesis of Conductive Polyaniline Using Laccase as Biocatalyst

    PubMed Central

    de Salas, Felipe; Pardo, Isabel; Salavagione, Horacio J.; Aza, Pablo; Amougi, Eleni; Vind, Jesper; Martínez, Angel T.; Camarero, Susana

    2016-01-01

    Polyaniline is a conductive polymer with distinctive optical and electrical properties. Its enzymatic synthesis is an environmentally friendly alternative to the use of harsh oxidants and extremely acidic conditions. 7D5L, a high-redox potential laccase developed in our lab, is the biocatalyst of choice for the synthesis of green polyaniline (emeraldine salt) due to its superior ability to oxidize aniline and kinetic stability at the required polymerization conditions (pH 3 and presence of anionic surfactants) as compared with other fungal laccases. Doses as low as 7.6 nM of 7D5L catalyze the polymerization of 15 mM aniline (in 24 h, room temperature, 7% yield) in the presence of different anionic surfactants used as doping templates to provide linear and water-soluble polymers. Aniline polymerization was monitored by the increase of the polaron absorption band at 800 nm (typical for emeraldine salt). Best polymerization results were obtained with 5 mM sodium dodecylbenzenesulfonate (SDBS) as template. At fixed conditions (15 mM aniline and 5mM SDBS), polymerization rates obtained with 7D5L were 2.5-fold the rates obtained with commercial Trametes villosa laccase. Moreover, polyaniline yield was notably boosted to 75% by rising 7D5L amount to 0.15 μM, obtaining 1g of green polyaniline in 1L-reaction volume. The green polymer obtained with the selected system (7D5L/SDBS) holds excellent electrochemical and electro-conductive properties displayed in water-dispersible nanofibers, which is advantageous for the nanomaterial to be readily cast into uniform films for different applications. PMID:27741301

  10. Detection of Carbon Monoxide Using Polymer-Carbon Composite Films

    NASA Technical Reports Server (NTRS)

    Homer, Margie L.; Ryan, Margaret A.; Lara, Liana M.

    2011-01-01

    A carbon monoxide (CO) sensor was developed that can be incorporated into an existing sensing array architecture. The CO sensor is a low-power chemiresistor that operates at room temperature, and the sensor fabrication techniques are compatible with ceramic substrates. Sensors made from four different polymers were tested: poly (4-vinylpryridine), ethylene-propylene-diene-terpolymer, polyepichlorohydrin, and polyethylene oxide (PEO). The carbon black used for the composite films was Black Pearls 2000, a furnace black made by the Cabot Corporation. Polymers and carbon black were used as received. In fact, only two of these sensors showed a good response to CO. The poly (4-vinylpryridine) sensor is noisy, but it does respond to the CO above 200 ppm. The polyepichlorohydrin sensor is less noisy and shows good response down to 100 ppm.

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

    NASA Astrophysics Data System (ADS)

    Lee, Taehwa; Guo, L. Jay

    2016-03-01

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

  12. Fabrication and performances of AI/CuO nano composite films for ignition application

    NASA Astrophysics Data System (ADS)

    Li, Yong; Gao, Yun; Jia, Xin; Zhou, Bin; Shen, Rui-Qi

    2015-07-01

    In an effort to explore the application possibility of composite films in ignition field, Al/CuO was fabricated on semiconductor bridge (SCB) chip by ion beam sputtering technique. Surface morphology and elemental composition of the composite films were analysed by scanning electron microscope (SEM) and energy dispersive spectrometer (EDS). Spatial size and duration of the products was detected with the open-air combustion experiment. The results showed that the prepared composite films surface is smooth, flat, and uniform. Element weight ratio meets the design requirements. And the chemical reaction of the Al/CuO nCFs improves output performances of ignition chip.

  13. Improved photoluminescence property of CTAB assisted polyaniline-AlZnO nanocomposite

    SciTech Connect

    Mitra, Mousumi; Banerjee, Dipali; Kargupta, Kajari; Ganguly, Saibal

    2015-06-24

    Polyaniline-Al doped ZnO ((PANI-AlZnO:: 70:30) nanocomposite was prepared via in situ chemical oxidative polymerization, while the hexagonal powder of AlZnO was synthesized via sol-gel technique, using Hexadecyltrimethylammonium bromide (CTAB) as a capping agent. The prepared nanocomposite was characterized by High resolution transmission electron microscopy (HRTEM), EDAX, X-ray diffraction (XRD) and Fourier transforms infrared (FTIR) spectra. The optical property of the nanomaterials is examined by photoluminescence (PL) spectra analysis. The XRD pattern confirms the formation of Al doped ZnO as well as PANI. The HRTEM images of the composite showed the formation of hexagonal AlZnO embedded in polyaniline matrix. EDAX spectrum shows the compositional analysis of the nanocomposite. FTIR spectra confirm the formation of nanocomposite of PANI and hexagonal AlZnO. The PL intensity of the nanocomposite is improved as compared to pure AlZnO.

  14. Photoactive composite films prepared from mixtures of polystyrene microgel dispersions and poly(3-hexylthiophene) solutions.

    PubMed

    Chen, Mu; Cui, Zhengxing; Edmondson, Steve; Hodson, Nigel; Zhou, Mi; Yan, Junfeng; O'Brien, Paul; Saunders, Brian R

    2015-11-14

    Whilst polystyrene microgels belong to the oldest family of microgel particles, their behaviours when deposited onto substrates or prepared as composites have received little attention. Because polystyrene microgels are solvent-swellable, and inherently colloidally stable, they are well suited to form composites with conjugated polymers. Here, we investigate the morphology and light absorption properties of spin coated composite films prepared from mixed dispersions of polystyrene microgels and poly(3-hexylthiophene) (P3HT) for the first time. We compare the morphologies of the composite films to spin coated microgel films. The films were studied using optical microscopy, SEM, AFM, wide-angle X-ray diffraction and UV-visible spectroscopy. The films contained flattened microgel particles with an aspect ratio of ∼10. Microgel islands containing hexagonally close packed particles were evident for both the pure microgel and microgel/P3HT composite films. The latter were electrically conducting. The composite film morphology was dependent on the microgel and P3HT concentration used for film preparation and a morphology phase diagram was constructed. The P3HT phase acted as an electrically conducting cement and increased the robustness of the films to solvent washing. The composite films were photoactive due to the P3HT component. The absorbance for the films was tuneable and increased linearly with both microgel and P3HT concentration. The results of the study should apply to other organic swellable microgel/conjugated polymer combinations and may lead to new colloidal composites for future optoelectronic applications. PMID:26347070

  15. Microcontact printing for patterning carbon nanotube/polymer composite films with electrical conductivity.

    PubMed

    Ogihara, Hitoshi; Kibayashi, Hiro; Saji, Tetsuo

    2012-09-26

    Patterned carbon nanotube (CNT)/acrylic resin composite films were prepared using microcontact printing (μCP). To prepare ink for μCP, CNTs were dispersed into propylene glycol monomethyl ether acetate (PGMEA) solution in which acrylic resin and a commercially available dispersant (Disperbyk-2001) dissolved. The resulting ink were spin-coated onto poly(dimethylsiloxane) (PDMS) stamps. By drying solvent components from the ink, CNT/polymer composite films were prepared over PDMS stamps. Contact between the stamps and glass substrates provided CNT/polymer composite patternings on the substrates. The transfer behavior of the CNT/polymer composite films depended on the thermal-treatment temperature during μCP; thermal treatment at temperatures near the glass-transition temperature (T(g)) of the acrylic resin was effective to form uniform patternings on substrates. Moreover, contact area between polymer and substrates also affect the transfer behavior. The CNT/polymer composite films showed high electrical conductivity, despite the nonconductivity of polymer components, because CNTs in the films were interconnected. The electrical conductivity of the composite films increased as CNT content in the film became higher; as a result, the composite patternings showed almost as high electrical conductivity as previously reported CNT/polymer bulk composites.

  16. Microcontact printing for patterning carbon nanotube/polymer composite films with electrical conductivity.

    PubMed

    Ogihara, Hitoshi; Kibayashi, Hiro; Saji, Tetsuo

    2012-09-26

    Patterned carbon nanotube (CNT)/acrylic resin composite films were prepared using microcontact printing (μCP). To prepare ink for μCP, CNTs were dispersed into propylene glycol monomethyl ether acetate (PGMEA) solution in which acrylic resin and a commercially available dispersant (Disperbyk-2001) dissolved. The resulting ink were spin-coated onto poly(dimethylsiloxane) (PDMS) stamps. By drying solvent components from the ink, CNT/polymer composite films were prepared over PDMS stamps. Contact between the stamps and glass substrates provided CNT/polymer composite patternings on the substrates. The transfer behavior of the CNT/polymer composite films depended on the thermal-treatment temperature during μCP; thermal treatment at temperatures near the glass-transition temperature (T(g)) of the acrylic resin was effective to form uniform patternings on substrates. Moreover, contact area between polymer and substrates also affect the transfer behavior. The CNT/polymer composite films showed high electrical conductivity, despite the nonconductivity of polymer components, because CNTs in the films were interconnected. The electrical conductivity of the composite films increased as CNT content in the film became higher; as a result, the composite patternings showed almost as high electrical conductivity as previously reported CNT/polymer bulk composites. PMID:22900673

  17. Organic memory device with polyaniline nanoparticles embedded as charging elements

    NASA Astrophysics Data System (ADS)

    Kim, Yo-Han; Kim, Minkeun; Oh, Sewook; Jung, Hunsang; Kim, Yejin; Yoon, Tae-Sik; Kim, Yong-Sang; Ho Lee, Hyun

    2012-04-01

    Polyaniline nanoparticles (PANI NPs) were synthesized and fabricated as charging elements for organic memory devices. The PANI NPs charging layer was self-assembled by epoxy-amine bonds between 3-glycidylpropyl trimethoxysilane functionalized dielectrics and PANI NPs. A memory window of 5.8 V (ΔVFB) represented by capacitance-voltage hysteresis was obtained for metal-pentacene-insulator-silicon capacitor. In addition, program/erase operations controlled by gate bias (-/+90 V) were demonstrated in the PANI NPs embedded pentacene thin film transistor device with polyvinylalcohol dielectric on flexible polyimide substrate. These results can be extended to development of fully organic-based electronic device.

  18. Effect of cross linking of PVA/starch and reinforcement of modified barley husk on the properties of composite films.

    PubMed

    Mittal, Aanchal; Garg, Sangeeta; Kohli, Deepak; Maiti, Mithu; Jana, Asim Kumar; Bajpai, Shailendra

    2016-10-20

    Barley husk (BH) was graft copolymerized by palmitic acid. The crystalline behavior of BH decreased after grafting. Poly vinyl alcohol (PVA)/starch (St) blend film, urea formaldehyde cross linked PVA/St films and composite films containing natural BH, grafted BH were prepared separately. The effect of urea/starch ratio, content of BH and grafted BH on the mechanical properties, water uptake (%), and biodegradability of the composite films was observed. With increase in urea: starch ratio from 0 to 0.5 in the blend, tensile strength of cross linked film increased by 40.23% compared to the PVA/St film. However, in grafted BH composite film, the tensile strength increased by 72.4% than PVA/St film. The degradation rate of natural BH composite film was faster than PVA/St film. Various films were characterized by SEM, FT-IR and thermal analysis. PMID:27474641

  19. Chemical composition of surface films on glass windows and implications for atmospheric chemistry

    NASA Astrophysics Data System (ADS)

    Lam, Buuan; Diamond, Miriam L.; Simpson, André J.; Makar, Paul A.; Truong, Jennifer; Hernandez-Martinez, Nadia A.

    Atmospherically derived surface films that cover impervious surfaces in cities, have areas comparable to that of atmospheric particulate matter (PM). The films compete with PM for sorption of volatile and semi-volatile organic compounds and alter the functionality of urban surfaces. The determination of surface-film composition is therefore vital to understanding their role in mediating chemical fate and transport within cities. Here, we show the composition of urban surface films collected from windows in downtown Toronto (Ontario, Canada) to be comprised of ˜94% inorganic compounds of which 8% are sulfate, 7% nitrate and 18% metals. Approximately 5% of the urban film mass is organic carbon, with ˜35% of the organic carbon mass corresponding to carbohydrates, ˜35% aliphatics, ˜20% aromatics and ˜10% carbonyls. The composition of surface films differs significantly from that of PM, suggesting differential accumulation, depositional degradation, and/or processes within films differing from those affecting PM. A rigid polymeric component comprising a small fraction of the organic carbon was also found, which may suggest direct deposition from environmental sources, or possible secondary in situ reactions within the film. Here, we suggest a potential mechanism for the oxidation of surface films to form organic polymers via radical initiation processes. Thus, the composition of surface films has important implications for chemical fate of contaminants within cities and presents a significant aspect of contaminant uptake that has not been considered in many air-quality models.

  20. Preparation of Polypyrrole-Protein Composite Films and the Electrochemically Controlled Release of Proteins.

    PubMed

    Jin, Juan; Huang, Zhongbing; Yin, Guangfu; Lin, Jiangli; Li, Qiuping; Han, Donghui

    2016-03-01

    It is fabricated that an electrically controlled release system based on the (poly-L-lactic acid)-mixed polypyrrole (PLLA-PPy) films through casting film of PPy and PLLA mixed solution on the glass plate, in which polyglutamic acid (PGlu)-doped PPy nanoparticles (NPs) with -50 nm diameter are synthesized via chemical oxidation. Surface conductivity of the composite film is (3.33 ± 2.01) x 10(-3) S/cm. Bovine serum albumin (BSA), as a model protein drug, is chemically linked onto the composite film via carbodiimide chemistry due to the good surface nano-structure of PLLA-PPy film. The releases of BSA from PLLA-PPy film under constant current and constant voltage can be achieved using the two-electrode electrochemical system. 6 h accumulative releases of BSA are 276 μg/cm2 and 176 μg/cm2 under 3 mA and 1 V electrical stimulation, respectively, accompanied with de-doping of PGlu and separation of a part of PPy NPs from the composite film. The results of cell experiment indicate that PGlu-doped PPy NPs in the prepared composite film have good cyto-compatibility. These results suggest that PPy-PLLA composite film would be able to be applied in the construction of degradable protein-drug-loaded scaffold for nerve tissue repair. PMID:27455630

  1. Construction of a Polyaniline Nanofiber Gas Sensor

    ERIC Educational Resources Information Center

    Virji, Shabnam; Weiller, Bruce H.; Huang, Jiaxing; Blair, Richard; Shepherd, Heather; Faltens, Tanya; Haussmann, Philip C.; Kaner, Richard B.; Tolbert, Sarah H.

    2008-01-01

    The electrical properties of polyaniline changes by orders of magnitude upon exposure to analytes such as acids or bases, making it a useful material for detection of these analytes in the gas phase. The objectives of this lab are to synthesize different diameter polyaniline nanofibers and compare them as sensor materials. In this experiment…

  2. Elastic Moduli of Nanoparticle-Polymer Composite Thin Films via Buckling on Elastomeric Substrates

    NASA Astrophysics Data System (ADS)

    Yuan, Hongyi; Karim, Alamgir; University of Akron Team

    2011-03-01

    Polymeric thin films find applications in diverse areas such as coatings, barriers and packaging. The dispersion of nanoparticles into the films was proven to be an effective method to generate tunable properties, particularly mechanical strength. However, there are very few methods for mechanical characterization of the composite thin films with high accuracy. In this study, nanometric polystyrene and polyvinyl alcohol films with uniformly dispersed cobalt and Cloisite nanoparticles at varying concentrations were synthesized via flow-coating and then transferred to crosslinked polydimethylsiloxane (PDMS) flexible substrates. The technique of Strain-Induced Elastic Buckling Instability for Mechanical Measurements (SIEBIMM) was employed to determine the elastic moduli of the films, which were calculated from the buckling patterns generated by applying compressive stresses. Results on moduli of films as a function of the concentrations of nanoparticles and the thicknesses of the composite films will be presented. *Corresponding author: alamgir@uakron.edu

  3. An emulsion polymerization process for soluble and electrically conductive polyaniline

    SciTech Connect

    Kinlen, P.J.; Ding, Y.; Graham, C.R.; Liu, J.; Remsen, E.E.

    1998-07-01

    A new emulsion process has been developed for the direct synthesis of the emeraldine salt of polyaniline (PANI) that is soluble in organic solvents. The process entails forming an emulsion composed of water, a water soluble organic solvent (e.g., 2-butoxyethanol), a water insoluble organic acid (e.g., dinonylnaphthalene sulfonic acid) and aniline. Aniline is protonated by the organic acid to form a salt which partitions into the organic phase. As oxidant (ammonium peroxydisulfate) is added, PANI salt forms in the organic phase and remains soluble. As the reaction proceeds, the reaction mixture changes from an emulsion to a two phase system, the soluble PANI remaining in the organic phase. With dinonylnaphthalene sulfonic acid (DNNSA) as the organic acid, the resulting product is truly soluble in organic solvents such as xylene and toluene (not a dispersion), of high molecular weight (M{sub w} > 22,000), film forming and miscible with many polymers such as polyurethanes, epoxies and phenoxy resins. As cast, the polyaniline film is only moderately conductive, (10{sup {minus}5} S/cm), however treatment of the film with surfactants such as benzyltriethylammonium chloride (BTEAC) or low molecular weight alcohols and ketones such as methanol and acetone increases the conductivity 2--3 orders of magnitude.

  4. KNN/BNT Composite Lead-Free Films for High-Frequency Ultrasonic Transducer Applications

    PubMed Central

    Lau, Sien Ting; Ji, Hong Fen; Li, Xiang; Ren, Wei; Zhou, Qifa; Shung, K. Kirk

    2011-01-01

    Lead-free K0.5Na0.5NbO3/Bi0.5Na0.5TiO3 (KNN/BNT) films have been fabricated by a composite sol-gel technique. Crystalline KNN fine powder was dispersed in the BNT precursor solution to form a composite slurry which was then spin-coated onto a platinum-buffered Si substrate. Repeated layering and vacuum infiltration were applied to produce 5-μm-thick dense composite film. By optimizing the sintering temperature, the films exhibited good dielectric and ferroelectric properties comparable to PZT films. A 193-MHz high-frequency ultrasonic transducer fabricated from this composite film showed a −6-dB bandwidth of approximately 34%. A tungsten wire phantom was imaged to demonstrate the capability of the transducer. PMID:21244994

  5. Continuous Preparation of Copper/Carbon Nanotube Composite Films and Application in Solar Cells.

    PubMed

    Luo, Xiao Gang; Le Wu, Min; Wang, Xiao Xia; Zhong, Xin Hua; Zhao, Ke; Wang, Jian Nong

    2016-02-01

    Realizing the continuous and large scale preparation of particle/carbon nanotube (CNT) composites with enhanced functionalities, and broad applications in energy conversion, harvesting, and storage systems, remains as a big challenge. Here, we report a scalable strategy to continuously prepare particle/CNT composite films in which particles are confined by CNT films. This is achieved by the continuous condensation and deposition of a cylindrical assembly of CNTs on a paper strip and the in situ incorporation of particles during the layer-by-layer deposition process. A Cu/CNT composite film is prepared as an example; such a film exhibits very high power conversion efficiency when it is used as a counter electrode in a solar cell, compared with previous materials under otherwise identical conditions. The proposed method can be extended to other CNT-based composite films with excellent functionalities for wide applications. PMID:26784865

  6. Strong composite films with layered structures prepared by casting silk fibroin-graphene oxide hydrogels

    NASA Astrophysics Data System (ADS)

    Huang, Liang; Li, Chun; Yuan, Wenjing; Shi, Gaoquan

    2013-04-01

    Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 +/- 16 MPa and a failure strain of 1.8 +/- 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 +/- 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets.Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 +/- 16 MPa and a failure strain of 1.8 +/- 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 +/- 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets. Electronic supplementary information (ESI) available: XPS spectrum of the SF-GO hybrid film, SEM images of lyophilized GO dispersion and the failure surface of GO film. See DOI: 10.1039/c3nr00196b

  7. ZrO2-ZnO composite thin films for humidity sensing

    NASA Astrophysics Data System (ADS)

    Velumani, M.; Meher, S. R.; Balakrishnan, L.; Sivacoumar, R.; Alex, Z. C.

    2016-05-01

    ZrO2-ZnO composite thin films were grown by reactive DC magnetron sputtering. X-ray diffraction studies reveal the composite nature of the films with separate ZnO and ZrO2 phase. Scanning electron microscopy studies confirm the nanocrystalline structure of the films. The films were studied for their impedometric relative humidity (RH) sensing characteristics. The complex impedance plot was fitted with a standard equivalent circuit consisting of an inter-granular resistance and a capacitance in parallel. The DC resistance was found to be decreasing with increase in RH.

  8. Investigation of polypyrrole/polyvinyl alcohol-titanium dioxide composite films for photo-catalytic applications

    NASA Astrophysics Data System (ADS)

    Cao, Shaoqiang; Zhang, Hongyang; Song, Yuanqing; Zhang, Jianling; Yang, Haigang; Jiang, Long; Dan, Yi

    2015-07-01

    Polypyrrole/polyvinyl alcohol-titanium dioxide (PPy/PVA-TiO2) composite films used as photo-catalysts were fabricated by combining TiO2 sol with PPy/PVA solution in which PPy was synthesized by in situ polymerization of pyrrole (Py) in polyvinyl alcohol (PVA) matrix and loaded on glass. The prepared photo-catalysts were investigated by X-ray diffraction (XRD), ultraviolet-visible diffuse reflection spectroscopy (UV-vis DRS), scanning electron microscopy (SEM), Fourier transform infrared (FT-IR) spectra and photoluminescence (PL). The results indicate that the composites have same crystal structure as the TiO2 and extend the optic absorption from UV region to visible light region. By detecting the variation ratio, detected by ultraviolet-vis spectroscopy, of model pollutant rhodamine B (RhB) solution in the presence of the composite films under both UV and visible light irradiation, the photo-catalytic performance of the composite films was investigated. The results show that the PPy/PVA-TiO2 composite films show better photo-catalytic properties than TiO2 film both under UV and visible light irradiation, and the photo-catalytic degradation of RhB follows the first-order kinetics. The effects of the composition of composite films and the concentration of RhB on the photo-catalytic performance, as well as the possible photo-catalytic mechanism, were also discussed. By photo-catalytic recycle experiments, the structure stability of the PPy/PVA-TiO2 composite film was investigated and the results show that the photo-catalytic activity under both UV and visible light irradiation have no significant decrease after four times of recycle experiments, suggesting that the photo-catalyst film is stable during the photo-catalytic process, which was also confirmed by the XRD pattern and FT-IR spectra of the composite film before and after photo-catalytic.

  9. The photosensitivity of carbon quantum dots/CuAlO2 films composites

    NASA Astrophysics Data System (ADS)

    Pan, Jiaqi; Sheng, Yingzhuo; Zhang, Jingxiang; Wei, Jumeng; Huang, Peng; Zhang, Xin; Feng, Boxue

    2015-07-01

    Carbon quantum dots/CuAlO2 films were prepared by a simple route through which CuAlO2 films prepared by sol-gel on crystal quartz substrates were composited with carbon quantum dots on their surface. The characterization results indicated that CuAlO2 films were well combined with carbon quantum dots. The photoconductivity of carbon quantum dots/CuAlO2 films was investigated under illumination and darkness switching, and was demonstrated to be significantly enhanced compared with CuAlO2 films. Through analysis, this enhancement of photoconductivity was attributed to the carbon quantum dots with unique up-converted photoluminescence behavior.

  10. O2/Ar Plasma Treatment for Enhancing the Biocompatibility of Hydroxyapatite Nanopowder and Polycaprolactone Composite Film.

    PubMed

    Ko, Yeong-Mu; Myung, Sung-Woon; Kim, Byung-Hoon

    2015-08-01

    In this study we performed O2/Ar plasma treatment to remove the polycaprolactone on hydroxyapatite nanopowder and polycaprolactone (HAp-NP/PCL) composite film. After plasma ashing, the HAp-NP was exposed on the composite film. The 25 wt% HAp-NP/PCL treated with plasma showed the hydrophilic surface property with reducing the aging effect. The MTT and ALP results indicated that the plasma etching increased the biocompatibility of HAp-NP/PCL composite film. The present simple plasma etching technique can be applicable in a development of biomaterials.

  11. Compositionally graded SiCu thin film anode by magnetron sputtering for lithium ion battery

    SciTech Connect

    Polat, B. D.; Eryilmaz, O. L.; Keles, O; Erdemir, A; Amine, Khalil

    2015-10-22

    Compositionally graded and non-graded composite SiCu thin films were deposited by magnetron sputtering technique on Cu disks for investigation of their potentials in lithium ion battery applications. The compositionally graded thin film electrodes with 30 at.% Cu delivered a 1400 mAh g-1 capacity with 80% Coulombic efficiency in the first cycle and still retained its capacity at around 600 mAh g-1 (with 99.9% Coulombic efficiency) even after 100 cycles. On the other hand, the non-graded thin film electrodes with 30 at.% Cu exhibited 1100 mAh g-1 as the first discharge capacity with 78% Coulombic efficiency but the cycle life of this film degraded very quickly, delivering only 250 mAh g-1 capacity after 100th cycles. Not only the Cu content but also the graded film thickness were believed to be the main contributors to the much superior performance of the compositionally graded SiCu films. We also believe that the Cu-rich region of the graded film helped reduce internal stress build-up and thus prevented film delamination during cycling. In particular, the decrease of Cu content from interface region to the top of the coating reduced the possibility of stress build-up across the film during cycling, thus leading to a high electrochemical performance.

  12. Structural determination and magnetic properties for Co-rubrene composite films on Si(1 0 0)

    NASA Astrophysics Data System (ADS)

    Hou, Yong-Jhih; Chang, Cheng-Hsun-Tony; Yang, Chun-Kai; Hsu, Chih-Yu; Jhou, Yen-Wei; Tsay, Jyh-Shen

    2015-11-01

    Because of the potential uses toward low-cost and flexible-substrate-based electronics, semiconducting organic materials have attracted much attention. In this contribution, structures and magnetic properties of Co-rubrene composite films on Si(1 0 0) have been studied by employing atomic force microscopy (AFM) and magneto-optic Kerr effect techniques. For composite films prepared by co-depositions of Co and rubrene on Si(1 0 0), the surface is smooth while a layered distribution of Co atoms is detected. For thick composite films, surfactant effects of rubrene molecules cause smooth surfaces and reduced interaction at the film/Si interface. For thin composite films, the formation of separated Co clusters in the films results in a larger coercive force due to the imperfection introduced by rough interface to impede the magnetization reversal. By increasing the rubrene concentration, more Co/rubrene interfaces are introduced in the composite films and the more rubrene served as a surfactant enhances the quality of the films. These information are valuable for future applications combining organic semiconductor and spintronics.

  13. Preparation of reduced graphene oxide/gelatin composite films with reinforced mechanical strength

    SciTech Connect

    Wang, Wenchao; Wang, Zhipeng; Liu, Yu; Li, Nan; Wang, Wei; Gao, Jianping

    2012-09-15

    Highlights: ► We used and compared different proportion of gelatin and chitosan as reducing agents. ► The mechanical properties of the films are investigated, especially the wet films. ► The cell toxicity of the composite films as biomaterial is carried out. ► The water absorption capabilities of the composite films also studied. -- Abstract: Graphene oxide (GO) was reduced by chitosan/gelatin solution and added to gelatin (Gel) to fabricate reduced graphene oxide/gelatin (RGO/Gel) films by a solvent-casting method using genipin as cross-linking agent. The structure and properties of the films were characterized by scanning electron microscopy (SEM), X-ray powder diffraction (XRD), thermogravimetric analysis (TGA) and UV–vis spectroscopy. The addition of RGO increased the tensile strength of the RGO/Gel films in both dry and wet states, but decreased their elongation at break. The incorperation of RGO also decreased the swelling ability of the films in water. Cell cultures were carried out in order to test the cytotoxicity of the films. The cells grew and reproduced well on the RGO/Gel films, indicating that the addition of RGO has no negative effect on the compatibility of the gelatin. Therefore, the reduced graphene oxide/gelatin composite is a promising biomaterial with excellent mechanical properties and good cell compatibility.

  14. Nanostructured graphene/Fe₃O₄ incorporated polyaniline as a high performance shield against electromagnetic pollution.

    PubMed

    Singh, Kuldeep; Ohlan, Anil; Pham, Viet Hung; R, Balasubramaniyan; Varshney, Swati; Jang, Jinhee; Hur, Seung Hyun; Choi, Won Mook; Kumar, Mukesh; Dhawan, S K; Kong, Byung-Seon; Chung, Jin Suk

    2013-03-21

    The development of high-performance shielding materials against electromagnetic pollution requires mobile charge carriers and magnetic dipoles. Herein, we meet the challenge by building a three-dimensional (3D) nanostructure consisting of chemically modified graphene/Fe3O4(GF) incorporated polyaniline. Intercalated GF was synthesized by the in situ generation of Fe3O4 nanoparticles in a graphene oxide suspension followed by hydrazine reduction, and further in situ polymerization with aniline to form a polyaniline composite. Spectroscopic analysis demonstrates that the presence of GF hybrid structures facilitates strong polarization due to the formation of a solid-state charge-transfer complex between graphene and polyaniline. This provides proper impedance matching and higher dipole interaction, which leads to the high microwave absorption properties. The higher dielectric loss (ε'' = 30) and magnetic loss (μ'' = 0.2) contribute to the microwave absorption value of 26 dB (>99.7% attenuation), which was found to depend on the concentration of GF in the polyaniline matrix. Moreover, the interactions between Fe3O4, graphene and polyaniline are responsible for superior material characteristics, such as excellent environmental (chemical and thermal) degradation stability and good electric conductivity (as high as 260 S m(-1)).

  15. Polymer layer ordering of polyaniline derivatives in PLED devices: Surface adsorption and characterization[Polymer Light Emitting Diodes

    SciTech Connect

    Advincula, R.C.; Knoll, W.; Frank, C.W.; Roitman, D.; Moon, R.; Sheats, J.

    1998-07-01

    The fabrication and characterization of polyaniline (PANI) derivatives deposited on ITO coated glass is investigated as possible hole injection layers for MEH-PPV based polymer light emitting diode (PLED) devices. This involved multilayer ordering by the alternate polyelectrolyte adsorption of polyaniline and sulfonated polyaniline with an oppositely charged polyelectrolyte from solution. A combination of spectroscopic and microscopic techniques was utilized to determine the layer ordering, film structure, morphology, and homogeneity. The deposition process generally showed a linear behavior for all pairs as shown by ellipsometry and UV-vis spectroscopy. However, surface plasmon spectroscopy (SPS) and AFM revealed that thicker films are accompanied by increased surface roughness regardless of concentration. Comparison in performance was made between bare ITO and PANI or SPANI coated devices. Initial investigations of PLED performance showed significant improvements in lifetime and efficiency compared to bare ITO.

  16. Incorporation of polyaniline nanofibres on graphene oxide by interfacial polymerization pathway for supercapacitor

    NASA Astrophysics Data System (ADS)

    Male, Umashankar; Srinivasan, Palaniappan; Singu, Bal Sydulu

    2015-09-01

    The aim of this work is to improve the supercapacitor performance of polyaniline (PANI). Polyaniline nano fibres are incorporated into graphene oxide (GO) layers by interfacial polymerization pathway, wherein PANI fibres are intercalated into GO layers and also cover the GO. PANI-GO hybrid composite is obtained in semi-crystalline form with good conductivity (1.7 S cm-1). The specific capacitance for PANI-GO (365 F g-1) is found to be higher than PANI (280 F g-1). At the energy density of 15 W h kg-1, the power density of PANI-GO (632 W kg-1) is higher than PANI (283 W kg-1).

  17. The nanoindentation applied to predict the interface delamination for the C/amorphous Si composite film

    NASA Astrophysics Data System (ADS)

    Han, Chang-Fu; Huang, Chao-Yu; Wu, Bo-Hsiung; Lin, Jen-Fin

    2009-10-01

    In the present study, the indentation depth corresponding to the pop-in arising in the loading process is found to be quite close to the C/amorphous Si composite film thickness, regardless of the C-film thickness. This load-depth behavior gives a clue that the occurrence of pop-in is perhaps related to the buckling of the composite film, which had already delaminated from the silicon substrate. This indentation depth of buckling predicted by the present model is quite close to the pop-in depth obtained from experimental results, regardless of the change in the C-film thickness. This characteristic reveals that the present model is developed successfully to predict the pop-in depth of a specimen, and the pop-in is indeed created due to the buckling of the composite film under a compression stress.

  18. Preparation and characterization of keratin and chicken egg white-templated luminescent Au cluster composite film

    NASA Astrophysics Data System (ADS)

    Xing, Yao; Liu, Hongling; Yu, Weidong

    2016-02-01

    The characterization of keratin-chicken egg white-templated luminescent Au cluster composite films were studied using fourier-transform infrared spectroscopy (FTIR) to demonstrate and quantify the secondary transformation of composite films. The results showed that the secondary structure of treated films was transformed from disordered structure to ordered conformation including α-helix conformation and β-pleated-sheet conformation due to the increase of protein-templated luminescent Au cluster. The absorption features of treated films were exhibited by the UV-vis spectra. The bule-shift and decreased intensity indicated the change of microenvironment due to the concentration of protein-templated luminescent Au cluster. The transmission electron microscopy images of composite films supported the aggregation resulting from microenvironment. The effect of protein-templated luminescent Au cluster was characterized by the laser scanning confocal microscope (LSCM) images which showed the gradually intensive luminescence with increasing Au cluster and the transformation from the whiskers to nanoparticle.

  19. Investigations of compositional separation in Co-Cr thin film recording media

    NASA Astrophysics Data System (ADS)

    Rogers, D. J.; Maeda, Y.; Takei, K.; Chapman, J. N.; Bernards, J. P. C.; Schrauwen, C. P. G.

    1994-02-01

    We investigated the effect of a Ge underlayer and substrate temperature during film deposition ( Ts) on the compositional distribution in Co 79Cr 21 films using spin echo nuclear magnetic resonance and preferential chemical etching. For films deposited at elevated Ts we observed drastic compositional separation (CS) leading to a Co enriched phase with approximately 5 at% Cr on both Ge and polyester. Chemical etching revealed chrysanthemum pattern (CP) type microstructures. For lower Ts films we observed less marked CS with a distinct etched microstructure in the film deposited on Ge and no clear etched microstructure in the film deposited on polyester. Results from NMR and chemical etching studies agreed very well with those from X-ray microanalysis.

  20. Diamond Composite Films for Protective Coatings on Metals and Method of Formation

    NASA Technical Reports Server (NTRS)

    Ong, Tiong P. (Inventor); Shing, Yuh-Han (Inventor)

    1997-01-01

    Composite films consisting of diamond crystallites and hard amorphous films such as diamond-like carbon, titanium nitride, and titanium oxide are provided as protective coatings for metal substrates against extremely harsh environments. A composite layer having diamond crystallites and a hard amorphous film is affixed to a metal substrate via an interlayer including a bottom metal silicide film and a top silicon carbide film. The interlayer is formed either by depositing metal silicide and silicon carbide directly onto the metal substrate, or by first depositing an amorphous silicon film, then allowing top and bottom portions of the amorphous silicon to react during deposition of the diamond crystallites, to yield the desired interlayer structure.

  1. Vertically oriented silica mesochannels as the template for electrodeposition of polyaniline nanostructures and their electrocatalytic and electroanalytical applications.

    PubMed

    Ding, Longhua; Li, Wanzhen; Wang, Qiaohong; Sun, Qinqin; He, Yayun; Su, Bin

    2014-02-10

    A mesoporous silica film (MSF) with vertically oriented mesochannels on a conductive substrate serves as a hard-template for electrodeposition of polyaniline (PANI). The PANI nanostructures thus prepared are orderly confined in silica mesochannels, eventually producing a robust hybrid film. The film displays a good electrocatalytic activity toward oxidation of ascorbic acid, and can be used for potentiometric pH sensing with a Nernstian response.

  2. Electrical anisotropies of carbon-nanotube-embedded graphene composite films

    NASA Astrophysics Data System (ADS)

    Kim, Daehan; Oh, Weontae; Kim, Jungsoo; Nam, Dae-Geun; Jang, Jaeho; Bae, Jong-Seong

    2014-08-01

    Graphite oxide (GO) was prepared by using the chemical oxidation of pristine graphite, and the GO dispersions in water were sprayed onto substrates. The prepared GO film was soaked in a hydrogen iodide (HI) water solution to make reduced graphite oxide (rGO) film. The resulting rGO film was analyzed using a 4-pin probe analyzer and current-voltage measurements, and the film's conductivities were compared in both the in-plane and the out-of-plane directions. In addition, the film's conductivities were analyzed according to the loadings (10-30 wt.%) of multiwalled carbon nanotubes (MWNTs) added to the rGO films. The experimentally-measured conductivities were compared and are discussed based on the film structures of rGO and MWNT-embedded rGO.

  3. Fluorescent of C-dot composite thin films and its properties

    SciTech Connect

    Mahen, Ea Cahya Septia Nuryadin, Bebeh W. Iskandar, Ferry Abdullah, Mikrajuddin Khairurrijal

    2014-02-24

    In the present work, we report the preparation of a fluorescent carbon nanodots (C-dots) epoxy composite thin films on a glass substrate. C-dots were prepared directly by a simple hydrothermal method using citric acid as a carbon source. The C-dots solutions were mixed with a transparent epoxy resin to form C-dot epoxy composite. Furthermore, the composite precursor was deposited on the glass substrate using a spin coating method in order to fabricate C-dot epoxy composite thin film. The transmittance intensity of C-dot composite film reached up to 90% in the visible light spectra. Using Swanopoel method, the film thickness of fabricated C-dot composite film was determined at about 1.45 μm, a value lies in a typical range needed for a wide range application. Thus, the C-dot composite film is promising in broadening applications in various fields such as energy conversion, optoelectronics, and display technology.

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

    DOEpatents

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

    2013-09-24

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

  5. Synthesis, pervaporation and gas separation studies of polyaniline blends

    SciTech Connect

    Huang, S.C.; Conklin, J.A.; Su, T.M.

    1995-12-01

    Membranes have been successfully produced from blends of polyaniline/polyacrylic acid and polyaniline/polyimide. The uniqueness of these membranes is the incorporation of {open_quotes}polymer dopants{close_quotes} in polyaniline. Conductivity measurements show that polyacrylic acid dopes the polyaniline. Pervaporation of water and water/acetic acid mixtures were performed using polyaniline and its polyacrylic acid blend. An improved flux over the polyaniline base form is observed. Polyaniline/polyimide blends were synthesized for gas permeability studies. These blends combine improved thermal stability relative to polyaniline with greater gas selectivity relative to polyimide. The blend shows an increase in permeability for all gases studied over both, polyaniline base and polyimide, while maintaining comparable separation factors.

  6. Conducting polymers and corrosion: Polyaniline on steel

    SciTech Connect

    Tallman, D.E.; Pae, Y.; Bierwagen, G.P.

    1999-08-01

    Polyaniline-coated steel panels were studied by electrochemical impedance spectroscopy (EIS) and electrochemical noise methods (ENM). EIS data for the polyaniline sample was obtained for increasing time of immersion. An increase in charge-transfer resistance (R{sub ct}) with immersion time was observed. ENM data showed that active electrochemical changes occurred during the early stages of immersion. The mean current from ENM exhibited a rather large oscillatory behavior during early stages of immersion, and the mean potential from ENM displayed a tendency toward positive values. Noise resistance (R{sub n}) values also showed initial oscillatory fluctuations, with values that reflected a poor barrier property for polyaniline coating. Tafel plots showed a lower corrosion rate and a more noble corrosion potential for the polyaniline-coated sample as compared to a bare steel sample. Electrochemical data confirmed that significant interactions between the polyaniline and steel occurred during he first 5 days of immersion, but that a continuing interaction occurred throughout the entire immersion period. EIS of a polyaniline/epoxy two-coated system on steel also was carried out. Performance of the polyaniline/epoxy system was superior to that of bare steel coated with epoxy alone.

  7. Nanostructured WS2-Ni composite films for improved oxidation, resistance and tribological performance

    NASA Astrophysics Data System (ADS)

    Xu, Shusheng; Gao, Xiaoming; Hu, Ming; Sun, Jiayi; Jiang, Dong; Zhou, Feng; Liu, Weimin; Weng, Lijun

    2014-01-01

    WS2 films were prepared by radio frequency sputtering. In order to improve its mechanical properties and oxidation resistance, Ni was used as the dopant and the effect of Ni content on the microstructure, anti-oxidation capability, mechanical and tribological properties of composite films were studied by energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, grazing incidence X-ray diffraction (GIXRD), high resolution transmission electron microscope (HRTEM), field emission scanning electron microscopy (FESEM), nano-indentation tester, scratch tester and ball-on-disk tribometer. WS2 existed in nanocrystalline 2H-WS2 structure and Ni an amorphous phase. Increasing the Ni content resulted in a microstructural change from columnar platelet structure of pure WS2 film to a fiber-like structure of the composite film at low Ni content (5.0 at%), and to a featureless structure at high Ni content (>10 at%). Meanwhile, the films became more and more compact and showed improved anti-oxidation capability. The films represented an increase in hardness with Ni content ranging from 0 to 10.3 at% due to the microstructure being densified, but exhibited high brittleness as the Ni content higher than 10 at%. The composite film at low Ni content of about 5.0 at% showed much better wear resistance than pure WS2 film, but became brittle and had poor wear resistances at high Ni content of above 10.3 at%. The WS2-5.0 at% Ni composite film exhibited the longest wear life of 5.8 × 105 cycles about sevenfold better than that of pure WS2 film in humid air. The wear mechanism was discussed in terms of the anti-oxidation capability of the films, morphology of the wear track and formation of transfer film.

  8. Electrical and Dielectric Properties of Exfoliated Graphite/Polyimide Composite Films with Low Percolation Threshold

    NASA Astrophysics Data System (ADS)

    Yu, Li; Zhang, Yi-He; Shang, Jiwu; Ke, Shan-Ming; Tong, Wang-shu; Shen, Bo; Huang, Hai-Tao

    2012-09-01

    Exfoliated graphite/polyimide composite films were synthesized by in situ polymerization. The electrical and dielectric properties of composite films with different volume fraction of exfoliated graphite were investigated over the frequency range from 103 Hz to 3 × 106 Hz. The dielectric behavior of the composite films was investigated by percolation theory and a microcapacitor model. A low percolation threshold f c ≈ 3.1 vol.% was obtained due to the high aspect ratio of the exfoliated graphite. Both the dielectric constant and alternating-current (AC) conductivity showed an abrupt increase in the vicinity of the percolation threshold. The ultralarge enhancement of the dielectric constant near and beyond the percolation threshold was due to Maxwell-Wagner-Sillars (MWS) interfacial polarization between the exfoliated graphite and polyimide and interface polarization between the composite film and electrode.

  9. Preparation and properties of biodegradable films from Sterculia urens short fiber/cellulose green composites.

    PubMed

    Jayaramudu, J; Reddy, G Siva Mohan; Varaprasad, K; Sadiku, E R; Sinha Ray, S; Varada Rajulu, A

    2013-04-01

    The development of commercially viable "green products", based on natural resources for the matrices and reinforcements, in a wide range of applications, is on the rise. The present paper focuses on Sterculia urens short fiber reinforced pure cellulose matrix composite films. The morphologies of the untreated and 5% NaOH (alkali) treated S. urens fibers were observed by SEM. The effect of 5% NaOH treated S. urens fiber (5, 10, 15 and 20% loading) on the mechanical properties and thermal stability of the composites films is discussed. This paper presents the developments made in the area of biodegradable S. urens short fiber/cellulose (SUSF/cellulose) composite films, buried in the soil and later investigated by the (POM), before and after biodegradation has taken place. SUSF/cellulose composite films have great potential in food packaging and for medical applications.

  10. Growth of BaTiO3-PVDF composite thick films by using aerosol deposition

    NASA Astrophysics Data System (ADS)

    Cho, Sung Hwan; Yoon, Young Joon

    2016-01-01

    Barium titanate (BaTiO3)-polyvinylidene fluoride (PVDF) composite thick films were grown by using aerosol deposition at room temperature with BaTiO3 and PVDF powders. To produce a uniform composition in ceramic and polymer composite films, which show a substantial difference in specific gravity, we used PVDF-coated BaTiO3 powders as the starting materials. An examination of the microstructure confirmed that the BaTiO3 were well distributed in the PVDF matrix in the form of a 0 - 3 compound. The crystallite size in the BaTiO3-PVDF composite thick films was 5 ˜ 50 times higher than that in pure BaTiO3 thick films. PVDF plays a role in suppressing the fragmentation of BaTiO3 powder during the aerosol deposition process and in controlling the relative permittivity.

  11. Strong composite films with layered structures prepared by casting silk fibroin-graphene oxide hydrogels.

    PubMed

    Huang, Liang; Li, Chun; Yuan, Wenjing; Shi, Gaoquan

    2013-05-01

    Composite films of graphene oxide (GO) sheets and silk fibroin (SF) with layered structures have been prepared by facile solution casting of SF-GO hydrogels. The as-prepared composite film containing 15% (by weight, wt%) of SF shows a high tensile strength of 221 ± 16 MPa and a failure strain of 1.8 ± 0.4%, which partially surpass those of natural nacre. Particularly, this composite film also has a high modulus of 17.2 ± 1.9 GPa. The high mechanical properties of this composite film can be attributed to its high content of GO (85 wt%), compact layered structure and the strong hydrogen bonding interaction between SF chains and GO sheets. PMID:23538717

  12. Preparation, characterization and application of polyaniline nanospheres to biosensing

    NASA Astrophysics Data System (ADS)

    Dhand, Chetna; Das, Maumita; Sumana, Gajjala; Srivastava, Avanish Kumar; Pandey, Manoj Kumar; Kim, Cheol Gi; Datta, Monika; Malhotra, Bansi Dhar

    2010-05-01

    Polyaniline nanospheres (PANI-NS) prepared by morphological transformation of micelle polymerized camphorsulfonic acid (CSA) doped polyaniline nanotubes (PANI-NT) in the presence of ethylene glycol (EG) have been characterized by X-ray diffraction, atomic force microscopy, transmission electron microscopy, scanning electron microscopy, Fourier transform infra-red and UV-Visible spectroscopy. A PANI-NS (60-80 nm) film deposited onto an indium-tin-oxide (ITO) coated glass plate by the solution casting method has been utilized for covalent immobilization of biomolecules (cholesterol oxidase (ChOx)) viaN-ethyl-N'-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) chemistry for fabrication of a cholesterol biosensor. The ChOx/PANI-NS/ITO bioelectrode detects cholesterol in the concentration range of 25 to 500 mg dL-1 with sensitivity of 1.3 × 10-3 mA mg-1 dL and regression coefficient of 0.98. Further, this PANI-NS based bioelectrode shows fast response time (10 s), low Michaelis-Menten constant (2.5 mM) and shelf-life of 12 weeks. The spherical nanostructure observed in the final morphology of the PANI-NS film is attributed to hydrogen bonding interactions between PANI-NT and EG.

  13. Graphene patterned polyaniline-based biosensor for glucose detection

    NASA Astrophysics Data System (ADS)

    Binh Nguyen, Hai; Chuc Nguyen, Van; Nguyen, Van Tu; Thanh Tam Ngo, Thi; Thinh Nguyen, Ngoc; Thu Huyen Dang, Thi; Tran, Dai Lam; Do, Phuc Quan; Nghia Nguyen, Xuan; Phuc Nguyen, Xuan; Khoi Phan, Hong; Phan, Ngoc Minh

    2012-06-01

    This paper describes a glucose electrochemical biosensor, layer-by-layer fabricated from graphene and polyaniline films. Graphene sheets (0.5×0.5 cm2) with the thickness of 5 nm (15 layers) were synthesized by thermal chemical vapor deposition (CVD) under ambient pressure on copper tapes. Then they were transferred into integrated Fe3O4-doped polyaniline (PANi) based microelectrodes. The properties of the nanocomposite films were thoroughly characterized by scanning electron microscopy (SEM), Raman spectroscopy, atomic force microscopy (AFM) and electrochemical methods, such as square wave voltametry (SWV) and chronoamperometry. The above graphene patterned sensor (denoted as Graphene/Fe3O4/PANi/GOx) shows much improved glucose sensitivity (as high as 47 μA mM‑1 cm‑2) compared to a non-graphene one (10–30 μA mM‑1 cm‑2, as previously reported in the literature). It can be expected that this proof-of-concept biosensor could be extended for other highly sensitive biodetection.

  14. Acid doping of polyaniline: Spectroscopic and electrochemical studies

    SciTech Connect

    Hatchett, D.W.; Josowicz, M.; Janata, J.

    1999-12-16

    A detailed investigation of the acid doping behavior of polyaniline has led to a robust and reproducible procedure for controlled adjustment of the redox state of dry polyaniline films. The initial step in this procedure is the casting of PANI films from formic acid. The subsequent exchange of the trapped formic acid for other primary dopants obtained from mono- and polyprotic acids (e.g., CH{sub 3}COO{sup {minus}}, BF{sub 4}{sup {minus}}, HSO{sub 4}{sup {minus}}, SO{sub 4}{sup 2{minus}}, H{sub 2}PO{sub 4}{sup {minus}}, and HPO{sub 4}{sup 2{minus}}) is demonstrated. The voltammetric and the spectroscopic behavior of the PANI doped with different anions indicate that both the protons and the anions of dopant acids influence the structure and redox properties of the polymer. The redox state of PANI doped with homologous series of chloroacetic and carboxylic acids correlates with the pK{sub a} of the dopant acid. These results show that it is possible to prepare the polymer with a desired oxidation state according to the pK{sub a} of the dopant acid of a given homologous series. The exchange of the formic acid for both stronger and weaker doping acid can be repeatedly accomplished by electrochemical cycling.

  15. Experimental Evaluation of Biodegradable Film Compositions Based on Gelatin with Colchicine.

    PubMed

    Bokeriya, L A; Bokeriya, O L; Sivtsev, V S; Novikova, S P; Salokhedinova, R R; Nikolashina, L N; Samsonova, N N; Gorodkov, A Yu; Serov, R A

    2016-07-01

    Biodegradable film compositions based on natural biopolymer gelatin with immobilized colchicine were prepared and their efficiency in prevention of the adhesion process in the pericardium was evaluated on rabbit model of postoperative pericarditis. The use of gelatin-based biodegradable film compositions significantly reduced the intensity of adhesion formation in the pericardial cavity, while immobilization of anti-inflammatory drug colchicine amplified their anti-adhesion activity. PMID:27496036

  16. Space radiation effects on poly(aryl-ether-ketone) thin films and composites

    NASA Technical Reports Server (NTRS)

    Funk, Joan G.; Sykes, George F., Jr.

    1988-01-01

    The purpose of this study was to assess the space durability of poly(aryl-ether-ketone) (PEEK) in the forms of films and graphite fiber reinforced composites. The influence of the film's crystallinity on electron radiation stability was evaluated using X-ray diffraction, DSC, FTIR, and mechanical property tests. The mechanical properties of the composites material were evaluated after electron radiation and after electron radiation followed by thermal cycling simulating 30 years in geosynchronous orbit.

  17. Processible Polyaniline Copolymers and Complexes.

    NASA Astrophysics Data System (ADS)

    Liao, Yun-Hsin

    1995-01-01

    Polyaniline (PANI) is an intractable polymer due to the difficulty of melt processing or dissolving it in common solvents. The purpose of the present investigation was to prepare a new class of conducting polyanilines with better solubility both in base and dope forms by (1) adding external salt to break aggregated chains, (2) introducing ring substituted units onto the backbone without disturbing the coplanar structure, and (3) complexing with polymeric dopants to form a soluble polymer complex. Aggregation of PANI chains in dilute solution was investigated in N-methyl-2-pyrrolidinone (NMP) by light scattering, gel permeation chromatography, and viscosity measurements. The aggregation of chains resulted in a negative second virial coefficient in light scattering measurement, a bimodal molecular weight distribution in gel permeation chromatography, and concave reduced viscosity curves. The aggregates can be broken by adding external salt, which resulting in a higher reduced viscosity. The driving force for aggregation is assumed to be a combination of hydrogen bonding between the imine and amine groups, and the rigidity of backbone. The aggregation was modeled to occur via side-on packing of PANI chains. The ring substituted PANI copolymers, poly(aniline -co-phenetidine) were synthesized by chemical oxidation copolymerization using ammonium persulfate as an oxidant. The degree of copolymerization declined with an increasing feed of o-phenetidine in the reaction mixture. The o-phenetidine had a higher reactivity than aniline in copolymerization resulting in a higher content of o-phenetidine in copolymers. The resulting copolymers can be readily dissolved in NMP up to 20% (w/w), and other common solvents, and solutions possess a longer gelation time. The highly soluble copolymer with 20 mole % o-phenetidine in the backbone has same order of conductivity as the unsubstituted PANI after it is doped by HCl. Complexation of PANI and polymeric dopant, poly

  18. Preparation technology and electrical explosion characteristics of titanium–boron composites as nanoenergetic films

    NASA Astrophysics Data System (ADS)

    Shenjiang, W. U.; Junhong, S. U.; Dangjuan, L. I.; Junqi, X. U.; Jingwei, L. I. U.

    2016-07-01

    Based on magnetron sputtering deposition technology, Ti and B single thin films are deposited on a Si substrate while varying the sputtering power, the working pressure and the Ar flow conditions. The effect of varying these conditions on the deposition rate, the roughness and the microstructure of these materials is studied. The optimal parameters for preparing Ti and B single thin films are identified according to the experimental and analysis results. Thus, the deposition parameters are optimized to minimize the roughness of the thin films (i.e. sputtering power: 225 and 120 W; working pressure: 0.8 and 0.3 Pa; Ar flow: 100 and 50 sccm for Ti and B thin films, respectively). The compositions and crystal orientation of the Ti and B thin films deposited at these conditions are investigated by x-ray diffraction. These optimized parameters are used while depositing Ti–B thin films on a polyimide substrate. Scanning electron microscopy is used to observe the microstructure of the Ti–B multi-layer nanoenergetic films. A close contact between the Ti film and the substrate is observed along with a clear boundary between the B and Ti films. Finally, the results of an electrical explosion experiment over a Ti–B composite thin film are discussed.

  19. Modeling the mechanics of graphene-based polymer composite film measured by the bulge test

    NASA Astrophysics Data System (ADS)

    Zhang, Jian-Jun; Sun, You-yi; Li, Dian-sen; Cao, Yang; Wang, Zuo; Ma, Jing; Zhao, Gui-Zhe

    2015-10-01

    Graphene-based polymer composite films have wide-ranging potential applications, such as in sensors, electromagnetic shielding, absorbing materials, corrosion resistance and so on. In addition, the practical applications of graphene-based polymer composite films are closely related to their mechanical properties. However, the mechanical properties of graphene-based polymer composite films are difficult to characterize with tensile tests. In this paper, the bugle test was used to investigate the mechanical properties of graphene-based polymer composite films. The experimental results show that the Young’s modulus of polymer composite films increases non-linearly with an increase in the doping content of graphene, and viscoelastic deformation is induced under cyclic loading conditions. Moreover, in order to describe their mechanical behavior, an ‘Arruda-Boyce’ finite-strain constitutive model (modified BPA model), based on the strain amplification hypothesis, and a traditional ‘Arruda-Boyce’ model was proposed, which incorporated many of the features of previous theories. The numerical treatment of the modified BPA model associated with finite element analysis is also discussed. This new model is shown to be able to predict the experimentally observed mechanical behavior of graphene based polymer composite films measured by the bugle test effectively.

  20. Compositional dependence of Young's moduli for amorphous FeCo-SiO{sub 2} thin films

    SciTech Connect

    Zhang, L.; Xie, J. L.; Deng, L. J.; Guo, Q.; Zhu, Z. W.; Bi, L.

    2011-04-01

    Systematic force-deflection measurements with microcantilevers and a combinatorial-deposition method have been used to investigate the Young's moduli of amorphous composite FeCo-SiO{sub 2} thin films as a function of film composition, with high compositional resolution. It is found that the modulus decreases monotonically with increasing FeCo content. Such a trend can be explained in terms of the metalloid atoms having a significant effect on the Young's moduli of metal-metalloid composites, which is associated with the strong chemical interaction between the metalloid and themetallic atoms rather than that between the metallic components themselves. This work provides an efficient and effective method to study the moduli of magnetic thin films over a largecomposition coverage, and to compare the relative magnitudes of moduli for differentcompositions at high compositional resolution.

  1. Charge transport across the metal-polymer film boundary

    NASA Astrophysics Data System (ADS)

    Yumaguzin, Yu. M.; Salikhov, T. R.; Shayakhmetov, R. U.; Salikhov, R. B.

    2016-08-01

    Thin polyaniline films were fabricated by thermal vacuum evaporation from a Knudsen effusion cell. The conducting properties of films synthesized under different evaporation conditions were studied. The enhancement of the emission capacity of a wolfram tip coated with a polyaniline film of a nanometer thickness was demonstrated experimentally. A model of the discovered effect was proposed. The obtained Fowler-Nordheim current-voltage characteristics were used to estimate the change in the electronic work function occurring when a thin film is deposited on the tip surface. The effective temperature of electrons emitted from the polyaniline film was determined based on the results of analysis of energy distributions, and the specific features of charge transport in the metal-polyaniline-vacuum system were examined. A model of energy bands of the metal-polymer film contact was also constructed.

  2. Fundamental aspects of polyimide dry film and composite lubrication: A review

    NASA Technical Reports Server (NTRS)

    Fusaro, R. L.

    1982-01-01

    The tribological properties of polyimide dry films and composites are reviewed. Friction coefficients, wear rates, transfer film characteristics, wear surface morphology, and possible wear mechanisms of several different polyimide films, polyimide-bonded solid lubricants, polyimide solid bodies, and polyimide composites are discussed. Such parameters as temperature, type of atmosphere, load, contact stress, and specimen configuration are investigated. Data from an accelerated test device (Pin-on-Disk) are compared to similar data obtained from an end use application test device (plain spherical bearing).

  3. Thin Film Heat Flux Sensor Development for Ceramic Matrix Composite (CMC) Systems

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Fralick, Gustave C.; Hunter, Gary W.; Zhu, Dongming; Laster, Kimala L.; Gonzalez, Jose M.; Gregory, Otto J.

    2010-01-01

    The NASA Glenn Research Center (GRC) has an on-going effort for developing high temperature thin film sensors for advanced turbine engine components. Stable, high temperature thin film ceramic thermocouples have been demonstrated in the lab, and novel methods of fabricating sensors have been developed. To fabricate thin film heat flux sensors for Ceramic Matrix Composite (CMC) systems, the rough and porous nature of the CMC system posed a significant challenge for patterning the fine features required. The status of the effort to develop thin film heat flux sensors specifically for use on silicon carbide (SiC) CMC systems with these new technologies is described.

  4. Applications industrielles de la polyaniline

    NASA Astrophysics Data System (ADS)

    Cottevieille, D.; Le Méhauté, A.; Challioui, C.

    1998-06-01

    Polyaniline (PANi) is the conducting polymer which gives the best potentiality for industrial applications. Studies has been undertaken by Alcatel Alsthom Recherche with the collaboration of Universities and DGA since 1985 have confirmed the potentiality of PANi for electrical and electronical industrial applications. Possibilities of industrial transfert were assessed, based on specific applications: high voltage (H.V.), microwave absorption, distributed filtering, electromagnetic shielding. La polyaniline (PANi) est le ploymère conducteur qui offre le plus de potentialité pour les applications industrielles. Les études entreprises depuis 1985 au sein d'Alcatel Alsthom Corporate Research Center (AA-CRC) en collaboration avec les universitaires et la Direction Générale de l'Armement (DGA) confirment la potentialité de la PANi pour des applications électriques et électroniques à caractère industriel. A l'aide d'applications spécifiques : haute-tension (H.T.), absorbants micro-ondes, filtrage distribué, blindage électromagnétique, nous évaluons les possibilités de transfert industriel.

  5. Dielectric and Ferroelectric Performance of Pb(Zr(x)Ti(1-x))O3 Thin Films with Compositional Gradients.

    PubMed

    He, Gang; Zhou, Yongju; Peng, Chao; Zhang, Yao; Pan, Wei

    2015-09-01

    A series of PZT thin films with compositional gradients were fabricated at ease by a combinatorial chemical solution deposition process. Their dielectric and ferroelectric properties are significantly different from uniform composition PZT films, depending on the composition, the span, and the direction of the compositional gradient. Among samples with the same average Zr content, the down-gradient thin films exhibit better dielectric and ferroelectric properties. PZT thin films with a narrow compositional gradient span favour better dielectric and ferroelectric properties. The down-gradient thin film PZT654 with a Zr-rich layer closest to the Pt substrate, in which the average composition is close to the morphotropic phase boundary (MPB, x = 0.52), shows the best dielectric and ferroelectric performance. These distinct thin films with different dielectric and ferroelectric properties could be designed by adjusting factors such as content, span and direction of the compositional gradient.

  6. Development and characterization of carrageenan/grapefruit seed extract composite films for active packaging.

    PubMed

    Kanmani, Paulraj; Rhim, Jong-Whan

    2014-07-01

    Carrageenan-based antimicrobial films were developed by incorporation of grape fruit seed extract (GSE) at different concentration into the polymer using a solvent casing method and their physical, mechanical, and antimicrobial properties were examined. The carrageenan/GSE composite films appeared yellowish tint due to the polyphenolic compounds in the GSE. SEM analysis showed rough surface with sponge like structures on the cross section of the films. FT-IR results indicated at GSE had good compatibility with carrageenan. The amorphous structure of polymer films was not changed by the incorporation of GSE. But, the addition of GSE increased moisture content, water vapor permeability, and surface hydrophilicity of the films. The tensile strength and elastic modulus decreased with increasing content of GSE, however, the elongation at break increased significantly up to 6.6μg/mL of GSE then decreased thereafter. Thermal stability of the films was not influenced by GSE incorporation. The carrageenan/GSE composite films exhibited great antibacterial activity against food borne pathogens. These results suggest that the carrageenan-based composite films have a high potential for being used as an antimicrobial or active food packaging applications. PMID:24832986

  7. Development and characterization of carrageenan/grapefruit seed extract composite films for active packaging.

    PubMed

    Kanmani, Paulraj; Rhim, Jong-Whan

    2014-07-01

    Carrageenan-based antimicrobial films were developed by incorporation of grape fruit seed extract (GSE) at different concentration into the polymer using a solvent casing method and their physical, mechanical, and antimicrobial properties were examined. The carrageenan/GSE composite films appeared yellowish tint due to the polyphenolic compounds in the GSE. SEM analysis showed rough surface with sponge like structures on the cross section of the films. FT-IR results indicated at GSE had good compatibility with carrageenan. The amorphous structure of polymer films was not changed by the incorporation of GSE. But, the addition of GSE increased moisture content, water vapor permeability, and surface hydrophilicity of the films. The tensile strength and elastic modulus decreased with increasing content of GSE, however, the elongation at break increased significantly up to 6.6μg/mL of GSE then decreased thereafter. Thermal stability of the films was not influenced by GSE incorporation. The carrageenan/GSE composite films exhibited great antibacterial activity against food borne pathogens. These results suggest that the carrageenan-based composite films have a high potential for being used as an antimicrobial or active food packaging applications.

  8. Structure and properties of composite films formed by cellulose nanocrystals and charged latex nanoparticles.

    PubMed

    Thérien-Aubin, Héloïse; Lukach, Ariella; Pitch, Natalie; Kumacheva, Eugenia

    2015-04-21

    We report the structural and optical properties of composite films formed from mixed suspensions of cellulose nanocrystals (CNCs) and fluorescent latex nanoparticles (NPs). We explored the effect of NP concentration, size, surface charge, glass transition temperature and film processing conditions on film structure and properties. The chiral nematic order, typical of CNC films, was preserved in films with up to 50 wt% of negatively-charged latex NPs. Composite films were characterized by macroscopically close-to-uniform fluorescence, birefringence, and circular dichroism properties. In contrast, addition of positively charged latex NPs led to gelation of CNC-latex suspensions and disruption of the chiral nematic order in the composite films. Large latex NPs disrupted the chiral nematic order to a larger extend than small NPs. Furthermore, the glass transition of latex NPs had a dramatic effect on the structure of CNC-latex films. Latex particles in the rubbery state were easily incorporated in the ordered CNC matrix and improved the structural integrity of its chiral nematic phase. PMID:25792388

  9. Nanostructure and Composition of Tribo-Boundary Films Formed in Ionic Liquid Lubrication

    SciTech Connect

    Qu, Jun; Chi, Miaofang; Meyer III, Harry M; Blau, Peter Julian; Dai, Sheng; Luo, Huimin

    2011-01-01

    Since the idea of using ionic liquids (ILs) as lubricants was raised in 2001, many studies have been conducted in this area and results have demonstrated superior lubricating performance for a variety of ionic liquids. It is widely believed that tribochemical reactions occur between the metal surface and the IL during the wear process to form a protective tribo-boundary film on the contact area that reduces friction and wear. However, the study of this critical boundary film has been limited to top surface two-dimensional topography examination and chemical analysis in the literature. A more comprehensive characterization is needed to help understand the film formation process and the lubricating mechanism. This study demonstrated a multi-technique three-dimensional approach to characterize the IL-formed boundary films, including top surface morphology examination, cross section nanostructure characterization, and layered chemical analysis. Characterization was carried out on both ferrous and aluminum surfaces lubricated by an ammonium IL. The focused-ion-beam (FIB) technique enabled TEM/EDS examination on the cross section of the boundary film to provide direct measurement of the film thickness, visualization of the nanostructure, and analysis of composition. In addition, composition-depth profiles were generated using XPS aided by ion-sputtering to reveal the composition change at different levels of the boundary film to investigate the film formation process.

  10. Composite TiO2-Carbon nano films with enhanced photocatalytic activity

    NASA Astrophysics Data System (ADS)

    Chakarov, Dinko; Sellappan, Raja

    2011-03-01

    Composite TiO2-carbon thin films prepared by physical vapor deposition techniques on fused silica substrates show enhanced photocatalytic activity, as compared to pure TiO2 films of similar thickness, towards decomposition of methanol to CO2 and water. Raman and XRD measurements confirm that annealed TiO2 films exhibit anatase structure while the carbon layer becomes graphitic. Characteristic for the composite films is an enhanced optical absorption in the visible range. The presence of the carbon film causes a shift of the TiO2 absorption edge and modifies its grain size to be smaller. The observed enhancement is attributed to synergy effects at the carbon-TiO2 interface, resulting in smaller crystallite size and anisotropic charge carrier transport, which in turn reduces their recombination probability. Supported by N-INNER through the Solar Hydrogen project (P30938-1 Solväte).

  11. Mercuric iodide composite films using polyamide, polycarbonate and polystyrene fabricated by casting

    NASA Astrophysics Data System (ADS)

    Ugucioni, J. C.; Ghilardi Netto, T.; Mulato, M.

    2010-10-01

    Mercuric iodide (HgI2) composite films were obtained by using the casting technique. Insulator polymers such as polyamide, polycarbonate and polystyrene were mixed to HgI2 crystallites forming a final sub-millimeter thick self-standing film. Fabrication temperature varied from 10 to 100 °C, and total fabrication time reached at most 5 min. The larger the fabrication temperature, the thinner the film and the smaller its electrical resistivity. Electrical characterization was performed in the dark, under UV illumination and under mammographic X-ray exposure. The final properties of the films are discussed and related to fabrication conditions. The optimized composite film might be a better candidate for use as X-ray detector for medical imaging, in place of the single HgI2 crystalline device.

  12. Control of composition and crystallinity in hydroxyapatite films deposited by electron cyclotron resonance plasma sputtering

    NASA Astrophysics Data System (ADS)

    Akazawa, Housei; Ueno, Yuko

    2014-01-01

    Hydroxyapatite (HAp) films were deposited by electron cyclotron resonance plasma sputtering under a simultaneous flow of H2O vapor gas. Crystallization during sputter-deposition at elevated temperatures and solid-phase crystallization of amorphous films were compared in terms of film properties. When HAp films were deposited with Ar sputtering gas at temperatures above 460 °C, CaO byproducts precipitated with HAp crystallites. Using Xe instead of Ar resolved the compositional problem, yielding a single HAp phase. Preferentially c-axis-oriented HAp films were obtained at substrate temperatures between 460 and 500 °C and H2O pressures higher than 1×10-2 Pa. The absorption signal of the asymmetric stretching mode of the PO43- unit (ν3) in the Fourier-transform infrared absorption (FT-IR) spectra was the narrowest for films as-crystallized during deposition with Xe, but widest for solid-phase crystallized films. While the symmetric stretching mode of PO43- (ν1) is theoretically IR-inactive, this signal emerged in the FT-IR spectra of solid-phase crystallized films, but was absent for as-crystallized films, indicating superior crystallinity for the latter. The Raman scattering signal corresponding to ν1 PO43- sensitively reflected this crystallinity. The surface hardness of as-crystallized films evaluated by a pencil hardness test was higher than that of solid-phase crystallized films.

  13. Characterization of multilayered and composite edible films from chitosan and beeswax.

    PubMed

    Velickova, Elena; Winkelhausen, Eleonora; Kuzmanova, Slobodanka; Moldão-Martins, Margarida; Alves, Vitor D

    2015-03-01

    Chitosan-based edible films were prepared and subjected to cross-linking reactions using sodium tripolyphosphate and/or to beeswax coating on both films interfaces. In addition, chitosan-beeswax emulsion-based films were produced. The goal of these modifications of the chitosan films was the improvement of their barrier to water vapor and to decrease their affinity to liquid water maintaining or improving the mechanical and optical properties of the original chitosan films. The cross-linking with tripolyphosphate decreased both the water vapor permeability and the water absorption capacity to about 55% and 50% of that of the original chitosan films, respectively. However, there was an increase in the films stiffness, revealed by the increased Young modulus from 42 kPa up to 336 kPa. The multilayered wax-chitosan-wax films exhibited a similar improvement of the barrier properties to water vapor, with the advantage of maintaining the mechanical properties of the original chitosan films. However, these wax-coated films showed a higher water absorption capacity, which is believed to be a consequence of water entry into small pores between the film and the wax layers. Regarding the film samples subjected to cross-linking and further coating with beeswax, a similar behavior as the uncoated cross-linked films was observed. The emulsion-based composite films were characterized by a substantial decrease of the water vapor permeability (40%), along with a decrease in their stiffness. Regarding the optical properties, all films presented a yellowish color with similar values of lightness, chroma, and hue.

  14. Preparation of a porcine plasma protein composite film and its application.

    PubMed

    Lee, Ji-Hyun; Song, Kyung Bin

    2015-01-01

    To use blood released from slaughtering houses, a porcine plasma protein (PPP)/nanoclay composite film was prepared. The tensile strength and elongation at break values of the PPP composite film with 5% nanoclay were 10.01 MPa and 6.55%, respectively. The PPP composite film containing 1% grapefruit seed extract (GSE) was applied to pork meat, and the populations of inoculated Escherichia coli O157:H7 and Listeria monocytogenes in the pork meat packaged with the PPP composite film decreased by 0.8 and 1.0 log CFU/g, respectively, after 7 days of storage compared to the populations of the control. In addition, thiobarbituric acid values in the pork meat packaged with the PPP composite film were less than those of the control sample during storage. These results suggest that the PPP nanocomposite film containing 1% GSE can be used as a packaging material to maintain the quality of pork meat. PMID:25248798

  15. A dense and strong bonding collagen film for carbon/carbon composites

    NASA Astrophysics Data System (ADS)

    Cao, Sheng; Li, Hejun; Li, Kezhi; Lu, Jinhua; Zhang, Leilei

    2015-08-01

    A strong bonding collagen film was successfully prepared on carbon/carbon (C/C) composites. The surface conditions of the modified C/C composites were detected by contact angle measurements, scanning electron microscope (SEM), X-ray photoelectron spectroscopy (XPS) and Raman spectra. The roughness, optical morphology, bonding strength and biocompatibility of collagen films at different pH values were detected by confocal laser scanning microscope (CLSM), universal test machine and cytology tests in vitro. After a 4-h modification in 30% H2O2 solution at 100 °C, the contact angle on the surface of C/C composites was decreased from 92.3° to 65.3°. Large quantities of hydroxyl, carboxyl and carbonyl functional groups were formed on the surface of the modified C/C composites. Then a dense and continuous collagen film was prepared on the modified C/C substrate. Bonding strength between collagen film and C/C substrate was reached to 8 MPa level when the pH value of this collagen film was 2.5 after the preparing process. With 2-day dehydrathermal treatment (DHT) crosslinking at 105 °C, the bonding strength was increased to 12 MPa level. At last, the results of in vitro cytological test showed that this collagen film made a great improvement on the biocompatibility on C/C composites.

  16. Development and characterization of an LDPE/chitosan composite antimicrobial film for chilled fish storage.

    PubMed

    Reesha, K V; Panda, Satyen Kumar; Bindu, J; Varghese, T O

    2015-08-01

    An antimicrobial packaging material was developed by uniformly embedding 1, 3 and 5% chitosan (w/w) in low density polyethylene matrix using maleic anhydride grafted LDPE as a compatible agent. The materials were mixed by compounding and blown into monolayer films via blown film extrusion. The developed films showed good barrier properties against oxygen. Characterization of the composite films with Fourier transform infrared spectroscopy revealed that chitosan and LDPE interacted well with each other. Overall migration showed better release of chitosan adduct from the LDPE matrix which enhanced the antibacterial properties of the films. The interaction between the LDPE/CS and maleic anhydride grafted LDPE had a decreasing effect on the tensile strength and heat sealing properties. Investigation on antimicrobial properties of LDPE/CS films showed 85-100% inhibition of Escherichia coli. Efficacy of LDPE/CS films was evaluated by using them as packaging material for chilled storage of Tilapia (Oreochromis mossambicus). Analysis of storage quality indices (peroxide value, free fatty acid, total volatile base nitrogen and aerobic plate count) revealed good antibacterial property and extension of shelf life of Tilapia in the chitosan incorporated novel composite films compared to virgin LDPE film.

  17. Flexible conductive nanocellulose combined with silicon nanoparticles and polyaniline.

    PubMed

    Park, Minsung; Lee, Dajung; Shin, Sungchul; Kim, Hyun-Joong; Hyun, Jinho

    2016-04-20

    Here we describe a unique conductive bacterial cellulose (BC) composite with silicon nanoparticles (SiNPs) and polyaniline. BC was used as a template for binding SiNPs resulting in a very promising anode material for Li-ion rechargeable batteries that showed a high specific capacity. The surfaces of the SiNPs were modified with phytic acid to enhance the binding of aniline monomer to the surface. A conformal coating of polyaniline (PANi) was formed on the modified SiNPs by in situ polymerization of aniline monomers. We also found that the phytic acid on the SiNPs was critical to ensure encapsulation of SiNPs with PANi. In addition, the phosphoric acid-tagged surface of the SiNPs enhanced the adhesion of SiNPs to the BC fibers. The resulting three dimensional network of BC was flexible and provided stress dissipation in the conductive BC composites. Flexural testing of conductive BC composites showed stable electrical conductivity even after repetitive bending over 100 times.

  18. Flexible conductive nanocellulose combined with silicon nanoparticles and polyaniline.

    PubMed

    Park, Minsung; Lee, Dajung; Shin, Sungchul; Kim, Hyun-Joong; Hyun, Jinho

    2016-04-20

    Here we describe a unique conductive bacterial cellulose (BC) composite with silicon nanoparticles (SiNPs) and polyaniline. BC was used as a template for binding SiNPs resulting in a very promising anode material for Li-ion rechargeable batteries that showed a high specific capacity. The surfaces of the SiNPs were modified with phytic acid to enhance the binding of aniline monomer to the surface. A conformal coating of polyaniline (PANi) was formed on the modified SiNPs by in situ polymerization of aniline monomers. We also found that the phytic acid on the SiNPs was critical to ensure encapsulation of SiNPs with PANi. In addition, the phosphoric acid-tagged surface of the SiNPs enhanced the adhesion of SiNPs to the BC fibers. The resulting three dimensional network of BC was flexible and provided stress dissipation in the conductive BC composites. Flexural testing of conductive BC composites showed stable electrical conductivity even after repetitive bending over 100 times. PMID:26876826

  19. Electrostatic Fabrication ("Electrospinning") of Nano-Fibers of Polyaniline Blends With Conventional Polymers

    NASA Astrophysics Data System (ADS)

    Norris, Ian D.; MacDiarmid, Alan G.; Shaker, Manal; Ko, Frank K.

    2000-03-01

    Ultrafine fibers of polyaniline doped with camphorsulfonic acid (PAn.HCSA) blended with polyethylene oxide (PEO) were prepared in air by a very simple, non-mechanical, electrostatic (``electrospinning"[1]) technique. Both the pure PEO and also the PAn.HCSA/PEO blend fibers had diameters ranging between 950 nm and 2100 nm, with a generally uniform thickness along the fiber. The uv-visible spectra were similar to those for cast films. However, the conductivity of the non-woven fiber blend mat was lower, as expected, than that of the cast film due to its high porosity. Fibers ( ~ 590 nm - 700 nm) from blends of non-doped polyaniline, emeraldine base (EB), were prepared from DMF solutions containing polyacrylonitrile. This work was financed jointly by the Office of Naval Research and the Army Research Office under the Multidisciplinary University Research Institute (MURI) program. [1] D.H. Reneker and I. Chun, Nanotechnology, 7 (1996) 216.

  20. Characterization of nanocrystalline gold/DLC composite films synthesized by plasma CVD technique

    NASA Astrophysics Data System (ADS)

    Paul, R.; Hussain, S.; Pal, A. K.

    2009-06-01

    Composite films containing gold nanoparticles embedded in diamond-like carbon (Au-DLC) matrix were deposited on glass and Si (1 0 0) substrates by using capacitatively coupled plasma (CCP) chemical vapour deposition technique (CVD). Particle size and metal volume fraction were tailored by varying the relative amount of argon in the methane + argon gas mixture in the plasma. Optical constants of the films were evaluated. Bonding environment in these films were obtained from Raman and Fourier transformed infrared spectra (FTIR) studies. Blue-shift of the surface plasmon resonance peak in the optical absorbance spectra of the films could be associated with the reduction of the particle size while red shift was observed with the increase in volume fraction of metal particles in the DLC films. Absorption spectra recorded in the reflection mode indicated dichromatism in these films.

  1. High loading of nanostructured ceramics in polymer composite thick films by aerosol deposition

    PubMed Central

    2012-01-01

    Low temperature fabrication of Al2O3-polyimide composite substrates was carried out by an aerosol deposition process using a mixture of Al2O3 and polyimide starting powders. The microstructures and dielectric properties of the composite thick films in relation to their Al2O3 contents were characterized by X-ray diffraction analysis. As a result, the crystallite size of α-Al2O3 calculated from Scherrer's formula was increased from 26 to 52 nm as the polyimide ratio in the starting powders increased from 4 to 12 vol.% due to the crushing of the Al2O3 powder being reduced by the shock-absorbing effect of the polyimide powder. The Al2O3-polyimide composite thick films showed a high loss tangent with a large frequency dependence when a mixed powder of 12 vol.% polyimide was used due to the nonuniform microstructure with a rough surface. The Al2O3-polyimide composite thick films showed uniform composite structures with a low loss tangent of less than 0.01 at 1 MHz and a high Al2O3 content of more than 75 vol.% when a mixed powder of 8 vol.% polyimide was used. Moreover, the Al2O3-polyimide composite thick films had extremely high Al2O3 contents of 95 vol.% and showed a dense microstructure close to that of the Al2O3 thick films when a mixed powder of 4 vol.% polyimide was used. PMID:22283973

  2. Fabrication of a Polyaniline Ultramicroelectrode via a Self Assembled Monolayer Modified Gold Electrode

    PubMed Central

    Bolat, Gulcin; Kuralay, Filiz; Eroglu, Gunes; Abaci, Serdar

    2013-01-01

    Herein, we report a simple and inexpensive way for the fabrication of an ultramicroelectrode and present its characterization by electrochemical techniques. The fabrication of polyaniline UME involves only two steps: modification of a gold (Au) electrode by self assembled monolayers (SAM) and then electrodeposition of polyaniline film on this thiol-coated Au electrode by using cyclic voltammetry and constant potential electrolysis methods. Two types of self-assembled monolayers (4-mercapto-1-butanol, MB, and 11-mercaptoundecanoic acid, MUA) were used, respectively, to see the effect of chain length on microelectrode formation. Microelectrode fabrication and utility of the surface was investigated by cyclic voltammetric measurements in a redox probe. The thus prepared polyaniline microelectrode was then used for DNA immobilization. Discrimination between double-stranded DNA (dsDNA) and single-stranded DNA (ssDNA) was obtained with enhanced electrochemical signals compared to a polyaniline-coated Au electrode. Different modifications on the electrode surfaces were examined using scanning electron microscopy (SEM). PMID:23797740

  3. Separation of Hydrogen Using an Electroless Deposited Thin-Film Palladium-Ceramic Composite Membrane

    SciTech Connect

    Ilias, S.; King, F.G.; Fan, Ting-Fang; Roy, S.

    1996-12-31

    The primary objective of this project was to prepare and characterize a hydrogen permselective palladium-ceramic composite membrane for high temperature gas separations and catalytic membrane reactors. Electroless plating method was used to deposit a thin palladium film on microporous ceramic substrate. The objective of this paper is to discuss the preparation and characterization of a thin-film palladium-ceramic composite membrane for selective separation of hydrogen at elevated temperatures and pressures. In this paper, we also present a model to describe the hydrogen transport through the palladium-ceramic composite membrane in a cocurrent flow configuration.

  4. High-performance flexible hydrogen sensor made of WS2 nanosheet–Pd nanoparticle composite film

    NASA Astrophysics Data System (ADS)

    Kuru, Cihan; Choi, Duyoung; Kargar, Alireza; Liu, Chin Hung; Yavuz, Serdar; Choi, Chulmin; Jin, Sungho; Bandaru, Prabhakar R.

    2016-05-01

    We report a flexible hydrogen sensor, composed of WS2 nanosheet–Pd nanoparticle composite film, fabricated on a flexible polyimide substrate. The sensor offers the advantages of light-weight, mechanical durability, room temperature operation, and high sensitivity. The WS2–Pd composite film exhibits sensitivity (R 1/R 2, the ratio of the initial resistance to final resistance of the sensor) of 7.8 to 50 000 ppm hydrogen. Moreover, the WS2–Pd composite film distinctly outperforms the graphene–Pd composite, whose sensitivity is only 1.14. Furthermore, the ease of fabrication holds great potential for scalable and low-cost manufacturing of hydrogen sensors.

  5. High-performance flexible hydrogen sensor made of WS₂ nanosheet-Pd nanoparticle composite film.

    PubMed

    Kuru, Cihan; Choi, Duyoung; Kargar, Alireza; Liu, Chin Hung; Yavuz, Serdar; Choi, Chulmin; Jin, Sungho; Bandaru, Prabhakar R

    2016-05-13

    We report a flexible hydrogen sensor, composed of WS2 nanosheet-Pd nanoparticle composite film, fabricated on a flexible polyimide substrate. The sensor offers the advantages of light-weight, mechanical durability, room temperature operation, and high sensitivity. The WS2-Pd composite film exhibits sensitivity (R 1/R 2, the ratio of the initial resistance to final resistance of the sensor) of 7.8 to 50,000 ppm hydrogen. Moreover, the WS2-Pd composite film distinctly outperforms the graphene-Pd composite, whose sensitivity is only 1.14. Furthermore, the ease of fabrication holds great potential for scalable and low-cost manufacturing of hydrogen sensors. PMID:27040653

  6. Facile Decoration of Polyaniline Fiber with Ag Nanoparticles for Recyclable SERS Substrate.

    PubMed

    Mondal, Sanjoy; Rana, Utpal; Malik, Sudip

    2015-05-20

    Facile synthesis of polyaniline@Ag composite has been successfully demonstrated by a simple solution-dipping method using high-aspect-ratio benzene tetracarboxylic acid-doped polyaniline (BDP) fiber as a nontoxic reducing agent as well as template cum stabilizer. In BDP@Ag composite, BDP fibers are decorated with spherical Ag nanoparticles (Ag NPs), and the population of Ag NPs on BDP fibers is controlled by changing the molar concentration of AgNO3. Importantly, Ag-NP-decorated BDP fibers (BDP@Ag composites) have been evolved as a sensitive materials for the detection of trace amounts of 4-mercaptobenzoic acid and rhodamine 6G as an analyte of surface-enhanced Raman scattering (SERS), and the detection limit is down to nanomolar concentrations with excellent recyclability. Furthermore, synthesized BDP@Ag composites are applied simultaneously as an active SERS substrate and a superior catalyst for reduction of 4-nitrothiophenol.

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

    NASA Astrophysics Data System (ADS)

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

    2016-07-01

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

  8. Plasma deposition of polymer composite films incorporating nanocellulose whiskers

    NASA Astrophysics Data System (ADS)

    Samyn, P.; Airoudj, A.; Laborie, M.-P.; Mathew, A. P.; Roucoules, V.

    2011-11-01

    In a trend for sustainable engineering and functionalization of surfaces, we explore the possibilities of gas phase processes to deposit nanocomposite films. From an analysis of pulsed plasma polymerization of maleic anhydride in the presence of nanocellulose whiskers, it seems that thin nanocomposite films can be deposited with various patterns. By specifically modifying plasma parameters such as total power, duty cycle, and monomer gas pressure, the nanocellulose whiskers are either incorporated into a buckled polymer film or single nanocellulose whiskers are deposited on top of a polymeric film. The density of the latter can be controlled by modifying the exact positioning of the substrate in the reactor. The resulting morphologies are evaluated by optical microscopy, AFM, contact angle measurements and ellipsometry.

  9. Electronic Defect States in Polyaniline.

    NASA Astrophysics Data System (ADS)

    Ginder, John Matthew

    The electronic defect states of the conducting polymer polyaniline are studied by a variety of magnetic and optical techniques. The insulating emeraldine base form (EB) of polyaniline can be converted to the conducting emeraldine salt form (ES) by treatment with aqueous acids such as HCl. This "protonic acid doping" process occurs via the bonding of protons to the polymer chain, without altering the number of chain electrons. Magnetic susceptibility studies reveal that a roughly linear growth of the Pauli paramagnetic susceptibility, and an increase in the density of Curie-like spins, accompanies this conversion. Consequently, the protonation-induced defects are mainly spin-1/2 polarons; further, the linear growth of the Pauli susceptibility suggests that fully protonated regions--metallic islands --grow with increasing doping level. The electronic structure of the metallic phase is proposed to be that of a polaron lattice with electronic bandwidth ~0.4 eV and polaron decay length ~2 A. The defects which accomodate excess charge in EB were also studied by near-steady-state photoinduced absorption experiments. Upon photoexcitation into the 2 eV absorption band in EB, several photoinduced features evolved. Induced bleachings of the existing transitions at 2.0 and 3.7 eV were observed; induced absorptions were found at 0.9, 1.4, and 3.0 eV. The 2.0 eV bleaching is consistent with the production of molecular charge-transfer excitons, which may relax to a different ring conformation causing long-lived bleaching, or to two separate charges on a single chain. Indeed, the induced absorptions at 1.4 and 3.0 eV are, by analogy with similar protonation -induced absorptions and by their bimolecular recombination kinetics, assigned to photoexcited polarons. Light-induced electron spin resonance experiments confirm the presence of photogenerated spins upon pumping into the excitonic absorption. Near-steady-state photoconductivity measurements on EB reveal a very small induced

  10. Direct electrochemical synthesis of reduced graphene oxide (rGO)/copper composite films and their electrical/electroactive properties.

    PubMed

    Xie, Guoxin; Forslund, Mattias; Pan, Jinshan

    2014-05-28

    Electrical contact materials with excellent performances are crucial for the development and safe use of electrical contacts in different applications. In our work, reduced graphene oxide (rGO)/copper (Cu) composite films, as potential electrical contact materials, have been synthesized on copper foil with one-step electrochemical reduction deposition method. Cyclic voltammetry (CV) was used to define the deposition conditions, and confocal Raman microscopy (CRM), X-ray photoelectron spectroscopy (XPS) and scanning electron microscopy (SEM) were used to characterize the chemical compositions, molecular and micro- and nano-structures of the composite films. Atomic force microscopy/scanning Kelvin probe force microscopy (AFM/SKPFM), conductive AFM (C-AFM) as well as impedance analysis were employed to evaluate the electroactive/electrical properties of the prepared composite films, respectively. The CRM and XPS results suggest that the rGO/Cu composite films can be synthesized through one-step electrochemical codeposition using suitable precursor solutions. Within a short deposition period, the growth of discrete nanograins in the composite film predominates, whereas pine-tree-leaf nanostructures are formed in the composite film when the deposition period is long, due to the chelating role of GO or rGO to regulate the growth rate of metallic copper nanograins. The electrical resistivity of the composite films is lower than the polished Cu foil and the electrodeposited Cu film, probably due to the higher conductivity (enhanced transfer of charge carriers) of the rGO incorporated in the composite films. The Volta potential variation in the rGO/Cu composite film is quite different from that in the electrodeposited Cu film. The electroactivity of the rGO/Cu composite films is higher than the electrodeposited Cu film, but lower than polished Cu foil, and the underlying mechanisms have been discussed.

  11. Electrochemical and Antimicrobial Properties of Diamondlike Carbon-Metal Composite Films

    SciTech Connect

    MORRISON, M. L.; BUCHANAN, R. A.; LIAW, P. K.; BERRY, C. J.; BRIGMON, R.; RIESTER, L.; JIN, C.; NARAYAN, R. J.

    2005-05-11

    Implants containing antimicrobial metals may reduce morbidity, mortality, and healthcare costs associated with medical device-related infections. We have deposited diamondlike carbon-silver (DLC-Ag), diamondlike carbon-platinum (DLC-Pt), and diamondlike carbon-silver-platinum (DLC-AgPt) thin films using a multicomponent target pulsed laser deposition process. Transmission electron microscopy of the DLC-silver and DLC-platinum composite films revealed that the silver and platinum self-assemble into nanoparticle arrays within the diamondlike carbon matrix. The diamondlike carbon-silver film possesses hardness and Young's modulus values of 37 GPa and 331 GPa, respectively. The diamondlike carbon-metal composite films exhibited passive behavior at open-circuit potentials. Low corrosion rates were observed during testing in a phosphate-buffered saline (PBS) electrolyte. In addition, the diamondlike carbon-metal composite films were found to be immune to localized corrosion below 1000 mV (SCE). DLC-silver-platinum films demonstrated exceptional antimicrobial properties against Staphylococcus bacteria. It is believed that a galvanic couple forms between platinum and silver, which accelerates silver ion release and provides more robust antimicrobial activity. Diamondlike carbon-silver-platinum films may provide unique biological functionalities and improved lifetimes for cardiovascular, orthopaedic, biosensor, and implantable microelectromechanical systems.

  12. Myoglobin within graphene oxide sheets and Nafion composite films as highly sensitive biosensor

    PubMed Central

    Guo, Changchun; Sun, Hong; Zhao, X.S.

    2012-01-01

    A highly sensitive biosensor was fabricated by incorporating myoglobin (Mb) within graphene oxide (GO) sheets and Nafion composite films. The stable composite Mb–GO–Nafion films were characterized by electrochemistry, scanning electron microscopy, Fourier transform infrared spectroscopy and UV–vis spectroscopy. It was found that Mb in Mb–GO–Nafion films retained its secondary structure similar to its native states. Cyclic voltammetry of Mb–GO–Nafion films showed a pair of well defined, quasi-reversible peaks at about −0.312 V vs saturated calomel electrode (SCE) at pH 5.5, corresponding to direct electron transfer (DET) between Mb and the glassy carbon electrode. Electrochemical parameter of Mb in Mb–GO–Nafion film such as apparent heterogeneous electron transfer rate constant (ks) and formal potential (Eo′) were obtained. The dependence of Eo′ on solution pH indicated that the DET reaction of Mb was coupled with proton transfer. Mb in the films displayed good electrocatalytic activities towards various substrates such as hydrogen peroxide, nitrite and oxygen, indicating that the composite films have potential applications in fabricating novel biosensors without using mediators. PMID:23576844

  13. Study of the physical properties of whey protein isolate and gelatin composite films.

    PubMed

    Jiang, Yanfeng; Li, Yanxia; Chai, Zhi; Leng, Xiaojing

    2010-04-28

    The relationships between the microstructural and physical properties of the whey protein isolate and gelatin (WPI/gelatin) composite films were investigated in the present work. Through the electrostatic effects at pH 8, WPI and gelatin molecules could form compact aggregates in solution, where a remarkable shrinkage of the gelatin molecules was observed, when the WPI/gelatin mass ratio was close to 50W:50G. FT-IR analysis indicated that hydrogen bonding also involved the aggregation and film-forming process. The melting temperature of the 50W:50G composite film increased by 9 degrees C compared with the single component films. However, this aggregation process also made the film network microstructure discontinuous, and led to a decline of the puncture strength of the film near 50W:50G; in contrast, the deformation and water vapor permeability of the composite films increased with the gelatin content, while the moisture content and solubility did not show significant variations.

  14. Study of phase transitions in NbN ultrathin films under composite ion beam irradiation

    NASA Astrophysics Data System (ADS)

    Prikhodko, K.; Gurovich, B.; Dement'eva, M.

    2016-04-01

    This work demonstrates implementation of Selective Displacement of Atoms (SDA) technique to change the crystal structure and atomic composition of thin superconductive film of NbN under low dose composite ion beam irradiation. All structure investigations were performed using High Resolution Transmission Electron Microscopy (HRTEM) technique by the analysis of Fourier transformation of bright field HRTEM images. It was found that composite ion beam irradiation induces the formation of niobium oxynitrides phases.

  15. Morphological, compositional, structural, and optical properties of Si-nc embedded in SiOx films

    PubMed Central

    2012-01-01

    Structural, compositional, morphological, and optical properties of silicon nanocrystal (Si-nc) embedded in a matrix of non-stoichiometric silicon oxide (SiOx) films were studied. SiOx films were prepared by hot filament chemical vapor deposition technique in the 900 to 1,400°C range. Different microscopic and spectroscopic characterization techniques were used. The film composition changes with the growth temperature as Fourier transform infrared spectroscopy, energy dispersive X-ray spectroscopy, and X-ray photoelectron spectroscopy reveal. High-resolution transmission electron microscopy supports the existence of Si-ncs with a diameter from 1 to 6.5 nm in the matrix of SiOx films. The films emit in a wide photoluminescent spectrum, and the maximum peak emission shows a blueshift as the growth temperature decreases. On the other hand, transmittance spectra showed a wavelength shift of the absorption border, indicating an increase in the energy optical bandgap, when the growth temperature decreases. A relationship between composition, Si-nc size, energy bandgap, PL, and surface morphology was obtained. According to these results, we have analyzed the dependence of PL on the composition, structure, and morphology of the Si-ncs embedded in a matrix of non-stoichiometric SiOx films. PMID:23110990

  16. Effects of antibacterial nanostructured composite films on vascular stents: hemodynamic behaviors, microstructural characteristics, and biomechanical properties.

    PubMed

    Cheng, Han-Yi; Hsiao, Wen-Tien; Lin, Li-Hsiang; Hsu, Ya-Ju; Sinrang, Andi Wardihan; Ou, Keng-Liang

    2015-01-01

    The purpose of this research was to investigate stresses resulting from different thicknesses and compositions of hydrogenated Cu-incorporated diamond-like carbon (a-C:H/Cu) films at the interface between vascular stent and the artery using three-dimensional reversed finite element models (FEMs). Blood flow velocity variation in vessels with plaques was examined by angiography, and the a-C:H/Cu films were characterized by transmission electron microscopy to analyze surface morphology. FEMs were constructed using a computer-aided reverse design system, and the effects of antibacterial nanostructured composite films in the stress field were investigated. The maximum stress in the vascular stent occurred at the intersections of net-like structures. Data analysis indicated that the stress decreased by 15% in vascular stents with antibacterial nanostructured composite films compared to the control group, and the stress decreased with increasing film thickness. The present results confirmed that antibacterial nanostructured composite films improve the biomechanical properties of vascular stents and release abnormal stress to prevent restenosis. The results of the present study offer the clinical benefit of inducing superior biomechanical behavior in vascular stents.

  17. Interplay Between Thin Film Ferroelectric Composition, Microstructure and Microwave Phase Shifter Performance

    NASA Technical Reports Server (NTRS)

    Mueller, Carl H.; VanKeuls, Frederick W.; Romanofsky, Robert R.; Alterovitz, Samuel A.; Miranda, Felix A.

    2003-01-01

    One of the keys to successfully incorporating ferroelectric films into Ku-band (12 to 18 GHz) phase shifters is to establish the composition, microstructure, and thickness required to meet the tuning needs, and tailor the film properties to meet these needs. Optimal performance is obtained when the film composition and device design are such that the device performance is limited by odd mode dielectric losses, and these losses are minimized as much as possible while still maintaining adequate tunability. The parameters required to maintain device performance will vary slightly depending on composition, but we can conclude that the best tuning-to-loss figures of merit (K-factor) are obtained when there is minimal variation between the in-plane and out-of-plane lattice parameters, and the full-width half maximum values of the BSTO (002) peaks are less than approximately 0.04 deg. We have observed that for phase shifters in which the ferroelectric crystalline quality and thickness are almost identical, higher losses are observed in films with higher BaISr ratios. The best performance was observed in phase shifters with Ba:Sr = 30:70. The superiority of this composition was attributed to several interacting factors: the B a: Sr ratio was such that the Curie temperature (180 K) was far removed from room temperature, the crystalline quality of the film was excellent, and there was virtually no difference between the inplane and out-of-plane lattice parameters of the film.

  18. Anomalous hopping conduction in nanocrystalline/amorphous composites and amorphous semiconductor thin films

    NASA Astrophysics Data System (ADS)

    Kakalios, James; Bodurtha, Kent

    Composite nanostructured materials consisting of nanocrystals (nc) embedded within a thin film amorphous matrix can exhibit novel opto-electronic properties. Composite films are synthesized in a dual-chamber co-deposition PECVD system capable of producing nanocrystals of material A and embedding then within a thin film matrix of material B. Electronic conduction in composite thin films of hydrogenated amorphous silicon (a-Si:H) containing nc-germanium or nc-silicon inclusions, as well as in undoped a-Si:H, does not follow an Arrhenius temperature dependence, but rather is better described by an anomalous hopping expression (exp[-(To/T)3/4) , as determined from the ``reduced activation energy'' proposed by Zabrodskii and Shlimak. This temperature dependence has been observed in other thin film resistive materials, such as ultra-thin disordered films of Ag, Bi, Pb and Pd; carbon-black polymer composites; and weakly coupled Au and ZnO quantum dot arrays. There is presently no accepted theoretical understanding of this expression. The concept of a mobility edge, accepted for over four decades, appears to not be necessary to account for charge transport in amorphous semiconductors. Supported by NSF-DMR and the Minnesota Nano Center.

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

    PubMed

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

    2014-08-27

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

  20. Preparation of the flexible ZrO2/C composite nanofibrous film via electrospinning

    NASA Astrophysics Data System (ADS)

    Yin, Xin; Song, Lixin; Xie, Xueyao; Zhou, Yangyang; Guan, Yingli; Xiong, Jie

    2016-07-01

    The flexible ZrO2/C composite nanofibrous film was fabricated by electrospinning and thermal treatment. Field-emission scanning electron microscopy, transmission electron microscopy, X-ray diffractometer, and Fourier transform infrared spectra were used to characterize the morphology and microstructure of the ZrO2/C composite nanofibrous film. The ZrO2/C nanofibers exhibited rough surface and had the average diameter of about 230 ± 35 nm. And the ZrO2 nanoparticles were incorporated in carbon matrix and in tetragonal and monoclinic. The flexural property of the ZrO2/C composite nanofibrous film was investigated in detail. The results showed that the flexural property of the nanofibrous film was greatly improved with addition of the ZrO2 nanoparticles. Besides, with the increase of the contents of ZrO2 nanoparticles, the flexural modulus of the nanofibrous film decreased, reached a lowest value, and then increased. The lowest flexural modulus of the ZrO2/C composite nanofibrous film in precursor concentration of 7.0 wt% was 8.55 ± 0.06 MPa.

  1. Nanostructure Titania Reinforced Conducting Polymer Composites

    NASA Astrophysics Data System (ADS)

    Kondawar, S. B.; Thakare, S. R.; Khati, V.; Bompilwar, S.

    Composites of polyaniline with synthesized nanostructured titania (TiO2) and polyaniline with commercial TiO2 have been in situ synthesized by oxidative chemical polymerization method. Sulfuric acid was used as dopant during the polymerization process. Sol-gel precipitates of nanostructured titania were synthesized by hydrolyzing the mixture of titanium chloride (TiCl3) and colloidal transparent solution of starch. Composite materials were subjected for comparison to spectroscopic and X-ray diffraction analysis. Strong coupling/interaction of titania with the imine nitrogen in polyaniline confirmed by FTIR spectral analysis. XRD shows the composite of synthesized titania with polyaniline have broaden peak as compared to that of commercial titania with polyaniline indicating particle size in the range of nanometer scale which is supported by 40 nm particle size of the synthesized titania from TEM picture. Increase in conductivity with increasing temperature was observed in both the composite materials.

  2. Formulation and evaluation of transdermal composite films of chitosan-montmorillonite for the delivery of curcumin

    PubMed Central

    Thakur, Garima; Singh, Amrinder; Singh, Inderbir

    2016-01-01

    Composite transdermal films of chitosan (CS)/montmorillonite K 10 (MMT) clay were prepared for the delivery of curcumin. CS/MMT films were evaluated for various physicochemical parameters. The films were characterized by Fourier transform infrared spectroscopy and X-ray diffraction analysis. Water uptake and swelling ratio of the films was found to decrease with increase in concentration of clay. Mechanical properties of the films were assessed in terms of tensile strength and extensibility using texture analyzer. Increase in tensile strength and reduction in extensibility was reported with increase in the clay content. This was attributed to the formation of intercalated structure and restriction in mobility of CS polymeric chains with the inclusion of clay particles. In vitro drug release study on transdermal films indicated pronounced sustained release of curcumin by the incorporation of clay particles in the CS polymer matrix. Stability study indicated no significant effect on physicochemical properties of films kept at 40°C and 75% RH for 3 months. Overall CS/MMT composite transdermal films exhibited improved mechanical and sustained drug release properties. PMID:27014616

  3. Nanoscale compositional analysis of NiTi shape memory alloy films deposited by DC magnetron sputtering

    SciTech Connect

    Sharma, S. K.; Mohan, S.; Bysakh, S.; Kumar, A.; Kamat, S. V.

    2013-11-15

    The formation of surface oxide layer as well as compositional changes along the thickness for NiTi shape memory alloy thin films deposited by direct current magnetron sputtering at substrate temperature of 300 °C in the as-deposited condition as well as in the postannealed (at 600 °C) condition have been thoroughly studied by using secondary ion mass spectroscopy, x-ray photoelectron spectroscopy, and scanning transmission electron microscopy-energy dispersive x-ray spectroscopy techniques. Formation of titanium oxide (predominantly titanium dioxide) layer was observed in both as-deposited and postannealed NiTi films, although the oxide layer was much thinner (8 nm) in as-deposited condition. The depletion of Ti and enrichment of Ni below the oxide layer in postannealed films also resulted in the formation of a graded microstructure consisting of titanium oxide, Ni{sub 3}Ti, and B2 NiTi. A uniform composition of B2 NiTi was obtained in the postannealed film only below a depth of 200–250 nm from the surface. Postannealed film also exhibited formation of a ternary silicide (Ni{sub x}Ti{sub y}Si) at the film–substrate interface, whereas no silicide was seen in the as-deposited film. The formation of silicide also caused a depletion of Ni in the film in a region ∼250–300 nm just above the film substrate interface.

  4. Manufacture of a Polyaniline Nanofiber Ammonia Sensor Integrated with a Readout Circuit Using the CMOS-MEMS Technique

    PubMed Central

    Liu, Mao-Chen; Dai, Ching-Liang; Chan, Chih-Hua; Wu, Chyan-Chyi

    2009-01-01

    This study presents the fabrication of a polyaniline nanofiber ammonia sensor integrated with a readout circuit on a chip using the commercial 0.35 μm complementary metal oxide semiconductor (CMOS) process and a post-process. The micro ammonia sensor consists of a sensing resistor and an ammonia sensing film. Polyaniline prepared by a chemical polymerization method was adopted as the ammonia sensing film. The fabrication of the ammonia sensor needs a post-process to etch the sacrificial layers and to expose the sensing resistor, and then the ammonia sensing film is coated on the sensing resistor. The ammonia sensor, which is of resistive type, changes its resistance when the sensing film adsorbs or desorbs ammonia gas. A readout circuit is employed to convert the resistance of the ammonia sensor into the voltage output. Experimental results show that the sensitivity of the ammonia sensor is about 0.88 mV/ppm at room temperature. PMID:22399944

  5. Single-Layer Light-Emitting Diodes Using Organometal Halide Perovskite/Poly(ethylene oxide) Composite Thin Films.

    PubMed

    Li, Junqiang; Bade, Sri Ganesh R; Shan, Xin; Yu, Zhibin

    2015-09-16

    Organometal halide perovskite and poly(ethylene oxide) composite thin films are studied. Single-layer light-emitting diodes using the composite thin film sandwiched between indium tin oxide and indium-gallium eutectic alloy exhibit a low turn-on voltage and high brightness because of the ionic conductivity of the composite film and the formation of a p-i-n homojunction. PMID:26247326

  6. Conducting transparent thin films based on Carbon Nanotubes — Conducting Polymers

    NASA Astrophysics Data System (ADS)

    Ferrer-Anglada, N.; Gomis, V.; El-Hachemi, Z.; Kaempgen, M.; Roth, S.

    2004-09-01

    The present work reports on the characterization and optimization of thin transparent and electrically conducting films (from 120 to 180 nm thick) based on single walled carbon nanotubes (CNT) and conducting polymers, polypyrrole (PPy) or polyaniline (PA). We obtained a number of different CNT-PPy doped with PTS or PF6 and CNT-PA under different parameters (electrodeposition time, density current or voltage) and analyzed the required properties, electrical conductivity and transparency, and other significant properties: Raman Spectroscopy, and AFM, from which we can estimate the film thickness. The electrochemical conditions for the polymer thin film deposition were studied in order to improve their conductivity and transparency. Compared to the well known transparent conducting oxides like ITO, the best of our composite thin films are from 10 to 100 times less conductive and highly transparent. As a great possibility, these conducting films could be prepared on a flexible substrate with a continuous deposition procedure.

  7. Self-lubricating polymer composites and polymer transfer film lubrication for space applications

    NASA Technical Reports Server (NTRS)

    Fusaro, Robert L.

    1990-01-01

    The use of self-lubricating polymers and polymer composites in space is somewhat limited today. In general, they are only used when other methods are inadequate. There is potential, however, for these materials to make a significant impact on future space missions if properly utilized. Some of the different polymers and fillers used to make self-lubricating composites are surveyed. The mechanisms of composite lubrication and wear, the theory behind transfer film lubricating mechanisms, and some factors which affect polymer composite wear and transfer are examined. In addition, some of the current space tribology application areas for self-lubricating polymer composites and polymer transfer are mentioned.

  8. Amperometric urea biosensors based on sulfonated graphene/polyaniline nanocomposite

    PubMed Central

    Das, Gautam; Yoon, Hyon Hee

    2015-01-01

    An electrochemical biosensor based on sulfonated graphene/polyaniline nanocomposite was developed for urea analysis. Oxidative polymerization of aniline in the presence of sulfonated graphene oxide was carried out by electrochemical methods in an aqueous environment. The structural properties of the nanocomposite were characterized by Fourier-transform infrared, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques. The urease enzyme-immobilized sulfonated graphene/polyaniline nanocomposite film showed impressive performance in the electroanalytical detection of urea with a detection limit of 0.050 mM and a sensitivity of 0.85 (μA · cm−2·mM−1. The biosensor achieved a broad linear range of detection (0.12–12.3 mM) with a notable response time of approximately 5 seconds. Moreover, the fabricated biosensor retained 81% of its initial activity (based on sensitivity) after 15 days of storage at 4°C. The ease of fabrication coupled with the low cost and good electrochemical performance of this system holds potential for the development of solid-state biosensors for urea detection. PMID:26346240

  9. Amperometric urea biosensors based on sulfonated graphene/polyaniline nanocomposite.

    PubMed

    Das, Gautam; Yoon, Hyon Hee

    2015-01-01

    An electrochemical biosensor based on sulfonated graphene/polyaniline nanocomposite was developed for urea analysis. Oxidative polymerization of aniline in the presence of sulfonated graphene oxide was carried out by electrochemical methods in an aqueous environment. The structural properties of the nanocomposite were characterized by Fourier-transform infrared, Raman spectroscopy, X-ray photoelectron spectroscopy, and scanning electron microscopy techniques. The urease enzyme-immobilized sulfonated graphene/polyaniline nanocomposite film showed impressive performance in the electroanalytical detection of urea with a detection limit of 0.050 mM and a sensitivity of 0.85 (μA · cm(-2)·mM(-1). The biosensor achieved a broad linear range of detection (0.12-12.3 mM) with a notable response time of approximately 5 seconds. Moreover, the fabricated biosensor retained 81% of its initial activity (based on sensitivity) after 15 days of storage at 4°C. The ease of fabrication coupled with the low cost and good electrochemical performance of this system holds potential for the development of solid-state biosensors for urea detection.

  10. First Orange Fluorescence Composite Film Based on Sm-Substituted Tungstophosphate and Its Electrofluorochromic Performance.

    PubMed

    Gao, Wenmei; Yu, Tian; Du, Yu; Wang, Ruiqiang; Wu, Lixin; Bi, Lihua

    2016-05-11

    We chose a Sm-containing sandwich-type tungstophosphate K3Cs8[Sm(PW11O39)2]·10H2O (SmPW11) as a molecular dyad, which contains photoluminescence and electrochromism components in a skeletal structure, and investigated its electrofluorochromic performance both in solution and in composite films. First, the electrochemical activity and luminescence property of SmPW11 were studied in different pH solutions to determine the optimal pH solution medium; and then, the electrofluorochromic performance of SmPW11 was investigated under the optimized pH solution medium. Subsequently, the composite films containing SmPW11 were prepared on quartz substrates and conductive ITO substrates through a layer-by-layer (LbL) assembly method, using PDDA and PEI as molecular linkers. Characterization methods of the composite films include UV-vis spectra, fluorescence spectroscopy, cyclic voltammetry (CV), bulk electrolysis with coulometry, chronoamperometry, X-ray photoelectron spectroscopy (XPS), and atomic force microscopy (AFM). Finally, in situ UV-vis and fluorescence spectroelectrochemical systems were used to research electrofluorochromic properties for the composite films under electrochemical modulation. The results indicate that the composite films display not only orange luminescence emission but also reversible orange luminescence switching behaviors manipulated by the redox process of tungstophosphate species PW11 via the energy transfer between the orange luminescence component Sm and electroreduced species of tungstophosphate PW11.

  11. Vanadium oxide-carbon nanotube composite films characterized by spectroscopic ellipsometry

    NASA Astrophysics Data System (ADS)

    He, Qiong; Xu, Xiangdong; Gu, Yu; Wang, Meng; Yao, Jie; Jiang, Yadong; Sun, Minghui; Ao, Tianhong; Lian, Yuxiang; Wang, Fu; Li, Xinrong

    2016-10-01

    Spectroscopic ellipsometry (SE) is utilized to characterize the vanadium oxide (VO x )-single walled carbon nanotube (SWCNT) composite films prepared by sol-gel. Five Tauc-Lorentz oscillators model is employed to describe the dispersions in the optical responses of VO x and VO x -SWCNT thin films. Results reveal that if the SWCNT concentration in the composite film is increased, the refractive index is decreased, while the extinction coefficient is increased. Moreover, higher SWCNT content leads to lower optical band gap (E g) but larger localized state (E e). Interestingly, both E g and E e values reach saturated at a SWCNT content of ~8 wt%. Particularly, the peak transition energies of the 5 Tauc-Lorentz oscillators have been assigned to the specific transitions according to the band structures of VO x . This work reveals the feasibility of investigating the optical properties and microstructures of VO x -SWCNT composite films by SE. These experimental results will be helpful for better understanding the VO x -SWCNT composite films, and promoting future characterizations of other SWCNT-based composites by SE.

  12. Automated Fiber Placement of PEEK/IM7 Composites with Film Interleaf Layers

    NASA Technical Reports Server (NTRS)

    Hulcher, A. Bruce; Banks, William I., III; Pipes, R. Byron; Tiwari, Surendra N.; Cano, Roberto J.; Johnston, Norman J.; Clinton, R. G., Jr. (Technical Monitor)

    2001-01-01

    The incorporation of thin discrete layers of resin between plies (interleafing) has been shown to improve fatigue and impact properties of structural composite materials. Furthermore, interleafing could be used to increase the barrier properties of composites used as structural materials for cryogenic propellant storage. In this work, robotic heated-head tape placement of PEEK/IM7 composites containing a PEEK polymer film interleaf was investigated. These experiments were carried out at the NASA Langley Research Center automated fiber placement facility. Using the robotic equipment, an optimal fabrication process was developed for the composite without the interleaf. Preliminary interleaf processing trials indicated that a two-stage process was necessary; the film had to be tacked to the partially-placed laminate then fully melted in a separate operation. Screening experiments determined the relative influence of the various robotic process variables on the peel strength of the film-composite interface. Optimization studies were performed in which peel specimens were fabricated at various compaction loads and roller temperatures at each of three film melt processing rates. The resulting data were fitted with quadratic response surfaces. Additional specimens were fabricated at placement parameters predicted by the response surface models to yield high peel strength in an attempt to gage the accuracy of the predicted response and assess the repeatability of the process. The overall results indicate that quality PEEK/lM7 laminates having film interleaves can be successfully and repeatability fabricated by heated head automated fiber placement.

  13. Composition spread studies of Nd1-xLaxNiO3 combinatorial thin films

    NASA Astrophysics Data System (ADS)

    Suchoski, Richard; Jin, Kui; Yasui, Shintaro; Greene, Richard; Takeuchi, Ichiro

    2013-03-01

    Rare earth nickelates have attracted a great deal of attention in recent years due to a host of interesting features, one being a transition from paramagnetic metal to antiferromagnetic insulator through distortions from the ideal perovskite unit cell. This metal-to-insulator transition (MIT) can be manipulated by modifying variables such as temperature, rare earth ion size, oxygen content, or stress from lattice-mismatched epitaxial thin film growth. Research on this family has been extensive, though there still exists an absence of thin film studies focusing on intermediate compositions. We have fabricated epitaxial thin film composition spreads of Nd1-xLaxNiO3 grown via combinatorial PLD to investigate these transitional compositions. While our films exhibit a smooth composition progression, we observe a composition threshold where orthorhombic NdNiO3 transforms to rhombohedral LaNiO3, correlating with disappearance of the MIT, and displays a non-Vegard evolution of the film's in-plane lattice constant in HRXRD and Raman scattering data of the A1g rotational mode. This work was performed at the Center for Nanophysics and Advanced Materials (CNAM) at UMD, and supported by AFO SR MURI Grant #FA95500910603.

  14. Temperature dependence of gas sensing behaviour of TiO{sub 2} doped PANI composite thin films

    SciTech Connect

    Srivastava, Subodh Sharma, Preetam; Singh, M.; Vijay, Y. K.; Sharma, S. S.; Sharma, Vinay; Rajura, Rajveer Singh

    2014-04-24

    In the present work we have reported the effect of temperature on the gas sensing properties of TiO{sub 2} doped PANI composite thin film based chemiresistor type gas sensors for hydrogen gas sensing application. PANI and TiO{sub 2} doped PANI composite were synthesized by in situ chemical oxidative polymerization of aniline at low temperature. The electrical properties of these composite thin films were characterized by I-V measurements as function of temperature. The I-V measurement revealed that conductivity of composite thin films increased as the temperature increased. The changes in resistance of the composite thin film sensor were utilized for detection of hydrogen gas. It was observed that at room temperature TiO{sub 2} doped PANI composite sensor shows higher response value and showed unstable behavior as the temperature increased. The surface morphology of these composite thin films has also been characterized by scanning electron microscopy (SEM) measurement.

  15. Development and characterization of an edible composite film based on chitosan and virgin coconut oil with improved moisture sorption properties.

    PubMed

    Binsi, P K; Ravishankar, C N; Srinivasa Gopal, T K

    2013-04-01

    An edible composite film was prepared from an emulsion system based on chitosan and virgin coconut oil (VCO). The effect of incorporation of VCO was evaluated at various concentrations and the optimum concentration was chosen based on resultant changes in the properties of the film. Addition of VCO in film forming solution resulted in increase in film thickness and marginal reduction in film transparency. Compatibility of VCO with chitosan was better at lower concentration of VCO as indicated by the microstructure of composite film in scanning electron micrographs. Phase separation was evident at higher level of oil incorporation and the optimal oil/chitosan ratio was determined to be at 0.5 to 1 mL/g chitosan. Furthermore, chemical interaction took place between VCO and chitosan as revealed by Fourier transform infrared spectroscopy data. Even though control chitosan films exhibited superior gas barrier properties, composite film with optimum VCO concentration revealed better mechanical and moisture sorption properties.

  16. Tuning the composition and nanostructure of Pt/Ir films via anodized aluminum oxide templated atomic layer deposition.

    SciTech Connect

    Comstock, D. J.; Christensen, S. T.; Elam, J. W.; Pellin, M. J.; Hersam, M. C.; Northwestern Univ.

    2010-09-23

    Nanostructured metal films have been widely studied for their roles in sensing, catalysis, and energy storage. In this work, the synthesis of compositionally controlled and nanostructured Pt/Ir films by atomic layer deposition (ALD) into porous anodized aluminum oxide templates is demonstrated. Templated ALD provides advantages over alternative synthesis techniques, including improved film uniformity and conformality as well as atomic-scale control over morphology and composition. Nanostructured Pt ALD films are demonstrated with morphological control provided by the Pt precursor exposure time and the number of ALD cycles. With these approaches, Pt films with enhanced surface areas, as characterized by roughness factors as large as 310, are reproducibly synthesized. Additionally, nanostructured Ptlr alloy films of controlled composition and morphology are demonstrated by templated ALD, with compositions varying systematically from pure Pt to pure Ir. Lastly, the application of nanostructured Pt films to electrochemical sensing applications is demonstrated by the non-enzymatic sensing of glucose.

  17. Electrosorption of ions from aqueous solutions with carbon nanotubes and nanofibers composite film electrodes

    NASA Astrophysics Data System (ADS)

    Wang, X. Z.; Li, M. G.; Chen, Y. W.; Cheng, R. M.; Huang, S. M.; Pan, L. K.; Sun, Z.

    2006-07-01

    Electrosorption of ions from aqueous solutions with carbon nanotubes and nanofibers (CNTs-CNFs) composite film electrodes has been demonstrated. The large area CNTs-CNFs film was directly grown on Ni plate by low pressure and low temperature thermal chemical vapor deposition. The CNTs-CNFs electrodes have great advantages such as low cost, easy operation, long-term reproducibility, and integrity of monolithic CNTs-CNFs film and current collector. Batch-mode experiments at low voltage (0.4-2V) were conducted in a continuously recycling system to investigate the electrosorption process. Purification of water with good reproducibility was achieved because of optimal pore size distribution of CNTs-CNFs composite films.

  18. Vacuum thermal evaporation of polyaniline doped with camphor sulfonic acid

    SciTech Connect

    Boyne, Devon; Menegazzo, Nicola; Pupillo, Rachel C.; Rosenthal, Joel; Booksh, Karl S.

    2015-05-15

    Intrinsically conducting polymers belong to a class of organic polymers with intriguing electronic and physical properties specifically for electro-optical applications. Significant interest into doped polyaniline (PAni) can be attributed to its high conductivity and environmental stability. Poor dissolution in most solvents has thus far hindered the successful integration of PAni into commercial applications, which in turn, has led to the investigations of various deposition and acidic doping methods. Physical vapor deposition methods, including D.C. magnetron sputtering and vacuum thermal evaporation, have shown exceptional control over physical film properties (thickness and morphology). However, resulting films are less conductive than films deposited by conventional methods (i.e., spin and drop casting) due to interruption of the hyperconjugation of polymer chains. Specifically, vacuum thermal evaporation requires a postdoping process, which results in incorporation of impurities and oxidation of surface moieties. In this contribution, thermally evaporated films, sequentially doped by vacuum evaporation of an organic acid (camphorsulfonic acid, CSA) is explored. Spectroscopic evidence confirms the successful doping of PAni with CSA while physical characterization (atomic force microscopy) suggests films retain good morphology and are not damaged by the doping process. The procedure presented herein also combines other postpreparation methods in an attempt to improve conductivity and/or substrate adhesion.

  19. Synthesis and physical properties of highly sulfonated polyaniline. Technical report

    SciTech Connect

    Wei, X.L.; Bobeczko, C.; Epstein, A.J.

    1996-03-01

    Sulfonated polyaniline (EB-SPAN) is a self-doped conducting polymer. It has a high water solubility and a novel pH-dependent DC conductivity that is of interest for fundamental science and also for applications in such areas as rechargeable battery and pH control technologies. The authors report here the extensive characterization and details of synthesis of a new form of sulfonated polyaniline (LEB-SPAN) which shows novel or significantly improved chemical and physical properties. LEB-SPAN has a much high sulfur to nitrogen ratio (S/N) of N approx. 0.75, 50% larger than that previously reported for EB-SPAN, S/N approx. 0.50. This change in composition leads to significant alteration of the properties including an order of magnitude increase in the room temperature DC conductivity to approx. 1 S./cm, nearly double the solubility in water, and a completely different pH-dependence of the oxidation potential (E1/2). For LEB-SPAN the DC conductivity is unaffected by pH over the range 0 < or = pH < or = 14, strikingly different from the behavior of both parent polyaniline and EB-SPAN which become insulating for pH > or = 3 and pH > or = 7.5; respectively. Temperature-dependent DC conductivity and EPR measurements for LEB-SPAN reveal a lower activation energy for the conductivity and a higher density of states at the Fermi energy as compared with EB-SPAN. The dramatic differences in the pH-dependence of the DC conductivity, cyclic voltammetry (CV), FTIR, and UV-Vis results for LEB-SPAN and EB-SPAN are shown to be a consequence of the much higher S/N ratio in LEB-SPAN.

  20. Resistivity minimum in granular composites and thin metallic films

    NASA Astrophysics Data System (ADS)

    Gerber, A.; Kishon, I.; Bartov, D.; Karpovski, M.

    2016-09-01

    We analyze the temperature dependence of conductivity in thick granular ferromagnetic compounds NiSi O2 and in thin weakly coupled films of Fe, Ni, and Py in the vicinity of the metal-to-insulator transition. Development of a resistivity minimum followed by a logarithmic variation of conductivity at lower temperatures is attributed to the granular structure of compounds and thin films fabricated by conventional deposition techniques. The resistivity minimum is identified as a transition between temperature dependent intragranular metallic conductance and thermally activated intergranular tunneling.

  1. Methods of making copper selenium precursor compositions with a targeted copper selenide content and precursor compositions and thin films resulting therefrom

    DOEpatents

    Curtis, Calvin J.; Miedaner, Alexander; van Hest, Marinus Franciscus Antonius Maria; Ginley, David S.; Leisch, Jennifer; Taylor, Matthew; Stanbery, Billy J.

    2011-09-20

    Precursor compositions containing copper and selenium suitable for deposition on a substrate to form thin films suitable for semi-conductor applications. Methods of forming the precursor compositions using primary amine solvents and methods of forming the thin films wherein the selection of temperature and duration of heating controls the formation of a targeted species of copper selenide.

  2. Nano-mechanical properties of nano-gold/DLC composite thin films

    NASA Astrophysics Data System (ADS)

    Paul, Rajib; Bhadra, Nilanjana; Mukhopadhyay, Anup Kumar; Bhar, Radhaballav; Pal, Arun Kumar

    2014-11-01

    Diamond-like-Carbon composite films, with embedded gold nanoparticles, were deposited onto glass substrates by using capacitively coupled plasma chemical vapour deposition (CCP-CVD) technique. The volume fraction of the metal nanoparticles in the films as well as the size of the nanoparticles was varied by varying the percentage of argon in the methane + argon mixture during the deposition. Bonding environments in these films were obtained from Raman and GIXRD. The nanomechanical and nanotribological properties of the Au-DLC nanocomposite films were evaluated. In situ SPM imaging was utilized to depict deformation characteristics developed during the static and dynamic contact events. Influence of metal incorporation on the extent of sp2/sp3 hybridization and thereby on the nanomechanical and nanotribological properties of the DLC films was studied.

  3. Morphology and Composition of Structured, Phase-Separated Behenic Acid-Perfluorotetradecanoic Acid Monolayer Films.

    PubMed

    Rehman, Jeveria; Araghi, Hessamaddin Younesi; He, Anqiang; Paige, Matthew F

    2016-05-31

    The phase separation of immiscible surfactants in mixed monolayer films provides an approach to physically manipulate important properties of thin films, including surface morphology, microscale composition, and mechanical properties. In this work, we predict, based upon existing miscibility studies and their thermodynamic underpinnings described in the literature, the miscibility and film morphology of mixed monolayers comprised of behenic acid (C21H43COOH) and perfluorotetradecanoic acid (C13F27COOH) in various molar ratios. Predictions are tested using a combination of experimental surface characterization methods for probing miscibility and film morphology at the solid/air and air/water interfaces. Film components were immiscible and phase-separated into chemically well-defined domains under a variety of experimental conditions, with monolayer morphology consistent with initial predictions. The extensibility of these basic predictions to other systems is discussed in the context of using these works for different perfluorinated surfactant molecules. PMID:27163482

  4. The photosensitivity of carbon quantum dots/CuAlO2 films composites.

    PubMed

    Pan, Jiaqi; Sheng, Yingzhuo; Zhang, Jingxiang; Wei, Jumeng; Huang, Peng; Zhang, Xin; Feng, Boxue

    2015-07-31

    Carbon quantum dots/CuAlO2 films were prepared by a simple route through which CuAlO2 films prepared by sol-gel on crystal quartz substrates were composited with carbon quantum dots on their surface. The characterization results indicated that CuAlO2 films were well combined with carbon quantum dots. The photoconductivity of carbon quantum dots/CuAlO2 films was investigated under illumination and darkness switching, and was demonstrated to be significantly enhanced compared with CuAlO2 films. Through analysis, this enhancement of photoconductivity was attributed to the carbon quantum dots with unique up-converted photoluminescence behavior. PMID:26150398

  5. Structural and compositional characterization of laser ablated CeO 2 thin films

    NASA Astrophysics Data System (ADS)

    Sánchez, F.; Varela, M.; Ferrater, C.; García-Cuenca, M. V.; Aguiar, R.; Morenza, J. L.

    1993-06-01

    CeO 2 thin films have been deposited on Si(100) substrates by laser ablation in ultrahigh vacuum. The structural and compositional properties of the films were studied by XRD, TEM, XPS and SIMS. All the films deposited in the temperature range 400-850°C have a preferential orientation ( hhh). The deposition in an oxygen environment (10 -4 mbar) results in a great reduction of the film crystallinity. The existance of a 5 nm thick amorphous layer between the CeO 2 film and the Si(100) substrate has been observed by TEM. XPS and SIMS results seem to indicate that this layer is a cerium silicade. SIMS profiles show that Ce diffuses toward the substrate, whereas O and Si do not diffuse.

  6. Cationic guar gum orchestrated environmental synthesis for silver nano-bio-composite films.

    PubMed

    Abdullah, Md Farooque; Ghosh, Sumanta Kumar; Basu, Sreyasree; Mukherjee, Arup

    2015-12-10

    This work is meant for environmentally friendly synthesis and functional evaluation of silver nanoparticles in a newer cationic guar biopolymer (GGAA). Assembly of molecules in lower size range (∼ 10 nm) was attained in a biopolymer entrapped bottom-up synthesis. Guar gum is a filming biopolymer. Nanoparticles encaged in cationic guar (GGAgnC) were preserved as films for months without any significant effect on particle size, distribution or plasmonic intensity. The new nano-bio-composite and films were characterized fully in FTIR, XRD, SEM and TEM studies. Silver nanoparticles induced surface water repellency remarkably and lowered moisture permeability. GGAgnC film water contact angle was recorded as 115° while, that in case of GGAA was 59°. GGAgnC expressed intense antimicrobial activity when tested against a range of microorganisms. Immobilized silver nanoparticles in GGAA can feasibly be used as filming microbicidals suitable for textiles, packaging and biomedical device applications.

  7. Novel green nano composites films fabricated by indigenously synthesized graphene oxide and chitosan.

    PubMed

    Khan, Younus H; Islam, Atif; Sarwar, Afsheen; Gull, Nafisa; Khan, Shahzad M; Munawar, Muhammad A; Zia, Saba; Sabir, Aneela; Shafiq, Muhammad; Jamil, Tahir

    2016-08-01

    Graphene oxide (GO) was indigenously synthesized from graphite using standard Hummers method. Chitosan-graphene oxide green composite films were fabricated by mixing aqueous solution of chitosan and GO using dilute acetic acid as a solvent for chitosan. Chitosan of different viscosity and calculated molecular weight was used keeping amount of GO constant in each composite film. The structural properties, thermal stability and mechanical properties of the composite films were investigated using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and tensile test. FTIR studies revealed the successful synthesis of GO from graphite powder and it was confirmed that homogenous blending of chitosan and GO was promising due to oxygenated functional groups on the surface of GO. XRD indicated effective conversion of graphite to GO as its strong peak observed at 11.06° as compared to pristine graphite which appeared at 26°. Moreover, mechanical analysis confirmed the effect of molecular weight on the mechanical properties of chitosan-GO composites showing that higher molecular weight chitosan composite (GOCC-1000) showed best strength (higher than 3GPa) compared to other composite films. Thermal stability of GOCC-1000 was enhanced for which residual content increased up to 56% as compared to the thermal stability of GOCC-200 whose residue was restricted to only 24%. The morphological analysis of the composites sheets by SEM was smooth having dense structure and showed excellent interaction, miscibility, compatibility and dispersion of GO with chitosan. The prepared composite films find their applications as biomaterials in different biomedical fields.

  8. Novel green nano composites films fabricated by indigenously synthesized graphene oxide and chitosan.

    PubMed

    Khan, Younus H; Islam, Atif; Sarwar, Afsheen; Gull, Nafisa; Khan, Shahzad M; Munawar, Muhammad A; Zia, Saba; Sabir, Aneela; Shafiq, Muhammad; Jamil, Tahir

    2016-08-01

    Graphene oxide (GO) was indigenously synthesized from graphite using standard Hummers method. Chitosan-graphene oxide green composite films were fabricated by mixing aqueous solution of chitosan and GO using dilute acetic acid as a solvent for chitosan. Chitosan of different viscosity and calculated molecular weight was used keeping amount of GO constant in each composite film. The structural properties, thermal stability and mechanical properties of the composite films were investigated using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM), thermogravimetric analysis (TGA) and tensile test. FTIR studies revealed the successful synthesis of GO from graphite powder and it was confirmed that homogenous blending of chitosan and GO was promising due to oxygenated functional groups on the surface of GO. XRD indicated effective conversion of graphite to GO as its strong peak observed at 11.06° as compared to pristine graphite which appeared at 26°. Moreover, mechanical analysis confirmed the effect of molecular weight on the mechanical properties of chitosan-GO composites showing that higher molecular weight chitosan composite (GOCC-1000) showed best strength (higher than 3GPa) compared to other composite films. Thermal stability of GOCC-1000 was enhanced for which residual content increased up to 56% as compared to the thermal stability of GOCC-200 whose residue was restricted to only 24%. The morphological analysis of the composites sheets by SEM was smooth having dense structure and showed excellent interaction, miscibility, compatibility and dispersion of GO with chitosan. The prepared composite films find their applications as biomaterials in different biomedical fields. PMID:27112859

  9. Composition measurement of epitaxial Sc x Ga1-x N films

    NASA Astrophysics Data System (ADS)

    Tsui, H. C. L.; Goff, L. E.; Barradas, N. P.; Alves, E.; Pereira, S.; Palgrave, R. G.; Davies, R. J.; Beere, H. E.; Farrer, I.; Ritchie, D. A.; Moram, M. A.

    2016-06-01

    Four different methods for measuring the compositions of epitaxial Sc x Ga1-x N films were assessed and compared to determine which was the most reliable and accurate. The compositions of epitaxial Sc x Ga1-x N films with 0 ≤ x ≤ 0.26 were measured directly using Rutherford backscattering (RBS) and x-ray photoelectron spectroscopy (XPS), and indirectly using c lattice parameter measurements from x-ray diffraction and c/a ratio measurements from electron diffraction patterns. RBS measurements were taken as a standard reference. XPS was found to underestimate the Sc content, whereas c lattice parameter and c/a ratio were not reliable for composition determination due to the unknown degree of strain relaxation in the film. However, the Sc flux used during growth was found to relate linearly with x and could be used to estimate the Sc content.

  10. Multiwalled carbon nanotube/polydimethylsiloxane composite films as high performance flexible electric heating elements

    NASA Astrophysics Data System (ADS)

    Yan, Jing; Jeong, Young Gyu

    2014-08-01

    High performance elastomeric electric heating elements were prepared by incorporating various contents of pristine multiwalled carbon nanotube (MWCNT) in polydimethylsiloxane (PDMS) matrix by using an efficient solution-casting and curing technique. The pristine MWCNTs were identified to be uniformly dispersed in the PDMS matrix and the electrical percolation of MWCNTs was evaluated to be at ˜0.27 wt. %, where the electrical resistivity of the MWCNT/PDMS composite films dropped remarkably. Accordingly, the composite films with higher MWCNT contents above 0.3 wt. % exhibit excellent electric heating performance in terms of temperature response rapidity and electric energy efficiency at constant applied voltages. In addition, the composite films, which were thermally stable up to 250 °C, showed excellent heating-cooling cyclic performance, which was associated with operational stability in actual electric heating applications.

  11. Ag nanoparticle dispersed PbTiO3 percolative composite thin film with high permittivity

    NASA Astrophysics Data System (ADS)

    Wang, Zongrong; Hu, Tao; Tang, Liwen; Ma, Ning; Song, Chenlu; Han, Gaorong; Weng, Wenjian; Du, Piyi

    2008-12-01

    Ag nanoparticle dispersed PbTiO3 percolative composite thin films were prepared in situ by sol-gel method using Pb(NO3)2, Ti(C4H9O)4, and AgNO3 as raw materials and lactic acid along with citric acid as complexing agent. The size of the Ag nanoparticles measured by ultraviolet-visible spectra is about 3nm. The percolation effect occurs in composite thin films. The composite exhibits relatively high dielectric constant which is about five times higher than that of PbTiO3 thin film and comparatively low dielectric loss comparable to pure PbTiO3 system. It is highly attractive in application of high quality dielectric devices and miniaturization.

  12. Multiwalled carbon nanotube/polydimethylsiloxane composite films as high performance flexible electric heating elements

    SciTech Connect

    Yan, Jing; Jeong, Young Gyu

    2014-08-04

    High performance elastomeric electric heating elements were prepared by incorporating various contents of pristine multiwalled carbon nanotube (MWCNT) in polydimethylsiloxane (PDMS) matrix by using an efficient solution-casting and curing technique. The pristine MWCNTs were identified to be uniformly dispersed in the PDMS matrix and the electrical percolation of MWCNTs was evaluated to be at ∼0.27 wt. %, where the electrical resistivity of the MWCNT/PDMS composite films dropped remarkably. Accordingly, the composite films with higher MWCNT contents above 0.3 wt. % exhibit excellent electric heating performance in terms of temperature response rapidity and electric energy efficiency at constant applied voltages. In addition, the composite films, which were thermally stable up to 250 °C, showed excellent heating-cooling cyclic performance, which was associated with operational stability in actual electric heating applications.

  13. Method for continuous control of composition and doping of pulsed laser deposited films

    DOEpatents

    Lowndes, Douglas H.; McCamy, James W.

    1995-01-01

    A method for growing a deposit upon a substrate of semiconductor material involves the utilization of pulsed laser deposition techniques within a low-pressure gas environment. The substrate and a target of a first material are positioned within a deposition chamber and a low-pressure gas atmosphere is developed within the chamber. The substrate is then heated, and the target is irradiated, so that atoms of the target material are ablated from the remainder of the target, while atoms of the gas simultaneously are adsorbed on the substrate/film surface. The ablated atoms build up upon the substrate, together with the adsorbed gas atoms to form the thin-film deposit on the substrate. By controlling the pressure of the gas of the chamber atmosphere, the composition of the formed deposit can be controlled, and films of continuously variable composition or doping can be grown from a single target of fixed composition.

  14. Method for continuous control of composition and doping of pulsed laser deposited films by pressure control

    DOEpatents

    Lowndes, Douglas H.; McCamy, James W.

    1996-01-01

    A method for growing a deposit upon a substrate of semiconductor material involves the utilization of pulsed laser deposition techniques within a low-pressure gas environment. The substrate and a target of a first material are positioned within a deposition chamber and a low-pressure gas atmosphere is developed within the chamber. The substrate is then heated, and the target is irradiated, so that atoms of the target material are ablated from the remainder of the target, while atoms of the gas simultaneously are adsorbed on the substrate/film surface. The ablated atoms build up upon the substrate, together with the adsorbed gas atoms to form the thin-film deposit on the substrate. By controlling the pressure of the gas of the chamber atmosphere, the composition of the formed deposit can be controlled, and films of continuously variable composition or doping can be grown from a single target of fixed composition.

  15. Dielectric and Energy Storage Properties of the Heterogeneous P(VDF-HFP)/PC Composite Films

    NASA Astrophysics Data System (ADS)

    Zhao, Xiaojia; Peng, Guirong; Zhan, Zaiji

    2016-09-01

    Polymer-based materials with a high discharge energy and low energy loss have attracted considerable attention for energy storage applications. A new class of polymer-based composite films composed of amorphous polycarbonate (PC) and poly(vinylidene fluoride-hexafluoropropylene) [P(VDF-HFP)] has been fabricated by simply solution blending followed by thermal treatment under vacuum. The results show that the diameter of the spherical phase for PC and the melting temperature of P(VDF-HFP) increase, and the crystallinity and crystallization temperature of P(VDF-HFP) decrease with increasing PC content. The phase transition from the polar β phase to weak polarity γ phase is induced by PC addition. Moreover, the Curie temperature of the P(VDF-HFP)/PC composite films shifts to a lower temperature. With the addition of PC, the permittivity, polarization and discharge energy of the P(VDF-HFP)/PC composite films slightly decrease. However, the energy loss is significantly reduced.

  16. Fabrication of Thermoplastic Composite Laminates Having Film Interleaves By Automated Fiber Placement

    NASA Technical Reports Server (NTRS)

    Hulcher, A. B.; Tiwari, S. N.; Marchello, J. M.; Johnston, Norman J. (Technical Monitor)

    2001-01-01

    Experiments were carried out at the NASA Langley Research Center automated Fiber placement facility to determine an optimal process for the fabrication of composite materials having polymer film interleaves. A series of experiments was conducted to determine an optimal process for the composite prior to investigation of a process to fabricate laminates with polymer films. The results of the composite tests indicated that a well-consolidated, void-free laminate could be attained. Preliminary interleaf processing trials were then conducted to establish some broad guidelines for film processing. The primary finding of these initial studies was that a two-stage process was necessary in order to process these materials adequately. A screening experiment was then performed to determine the relative influence of the process variables on the quality of the film interface as determined by the wedge peel test method. Parameters that were found to be of minor influence on specimen quality were subsequently held at fixed values enabling a more rapid determination of an optimal process. Optimization studies were then performed by varying the remaining parameters at three film melt processing rates. The resulting peel data were fitted with quadratic response surfaces. Additional specimens were fabricated at levels of high peel strength as predicted by the regression models in an attempt to gage the accuracy of the predicted response and to assess the repeatability of the process. The overall results indicate that quality laminates having film interleaves can be successfully and repeatably fabricated by automated fiber placement.

  17. Properties of cathodic arc deposited high-temperature superconducting composite thin films on Ag substrates

    NASA Astrophysics Data System (ADS)

    Chae, M. S.; Simnad, M. T.; Maple, M. B.; Anders, S.; Anders, A.; Brown, I. G.

    1996-02-01

    High temperature superconducting composite thin films on Ag substrates were prepared by cathodic arc deposition of alloy precursors. The deposition technique employed a cathode comprised of a precursor alloy for the vacuum arc plasma source. The precursor alloy was prepared by multiple arc-melting of mixed metallic constituents of the high-temperature superconducting material Bi 2Sr 2CaCu 2O y (Bi2212) and 50 wt.% of Ag. The presence of silver in the precursor alloy film was expected to allow accommodation of the lattice and thermal expansion mismatch between the oxidized film and the silver substrate. The as-deposited film could be formed to practically any desirable shape before being subjected to heat treatments. Following deposition, controlled oxidation of the precursor alloy thin film on the Ag substrate was performed to produce the superconducting composite on the silver substrate. After the heat treatment, the composite film consisted of Bi2212 highly c-axis oriented normal to the Ag substrate.

  18. Pulsed laser deposition of carbon nanotube and polystyrene-carbon nanotube composite thin films

    NASA Astrophysics Data System (ADS)

    Stramel, A. A.; Gupta, M. C.; Lee, H. R.; Yu, J.; Edwards, W. C.

    2010-12-01

    In this work, we report on the fabrication of carbon nanotube thin films via pulsed laser deposition using a pulsed, diode pumped, Tm:Ho:LuLF laser with 2 μm wavelength. The thin films were deposited on silicon substrates using pure carbon nanotube targets and polystyrene-carbon nanotube composite targets. Raman spectra, scanning electron micrographs, and transmission electron micrographs show that carbon nanotubes are present in the deposited thin films, and that the pulsed laser deposition process causes minimal degradation to the quality of the nanotubes when using pure carbon nanotube targets.

  19. Synthesis and gas separation studies of substituted polyaniline membranes

    SciTech Connect

    Su, T.M.; Kwon, A.H.; Lew, B.M.; Kaner, R.B.

    1996-10-01

    Polyaniline is a conjugated polymer that can be reversibly doped and undoped using common acids and bases. In the doped state, polyaniline is thermally and environmentally stable and electrically conducting. Polyaniline has shown promise as a gas separation membrane, however, it is limited by poor thermal processability and solvent solubility. The solvent solubility is increased for ethyl and methoxy substituted polyaniline. The smooth free-standing membranes cast from these substituted polymers exhibit an increase in gas permeability compared to the base form of polyaniline, but a decrease in selectivity.

  20. Synthesis, characterization and antibacterial activity of biodegradable starch/PVA composite films reinforced with cellulosic fibre.

    PubMed

    Priya, Bhanu; Gupta, Vinod Kumar; Pathania, Deepak; Singha, Amar Singh

    2014-08-30

    Cellulosic fibres reinforced composite blend films of starch/poly(vinyl alcohol) (PVA) were prepared by using citric acid as plasticizer and glutaraldehyde as the cross-linker. The mechanical properties of cellulosic fibres reinforced composite blend were compared with starch/PVA crossed linked blend films. The increase in the tensile strength, elongation percentage, degree of swelling and biodegradability of blend films was evaluated as compared to starch/PVA crosslinked blend films. The value of different evaluated parameters such as citric acid, glutaraldehyde and reinforced fibre to starch/PVA (5:5) was found to be 25 wt.%, 0.100 wt.% and 20 wt.%, respectively. The blend films were characterized using Fourier transform-infrared spectrophotometry (FTIR), scanning electron microscopy (SEM) and thermogravimetric analysis (TGA/DTA/DTG). Scanning electron microscopy illustrated a good adhesion between starch/PVA blend and fibres. The blend films were also explored for antimicrobial activities against pathogenic bacteria like Staphylococcus aureus and Escherichia coli. The results confirmed that the blended films may be used as exceptional material for food packaging.

  1. Superconducting properties and chemical composition of NbTiN thin films with different thickness

    SciTech Connect

    Zhang, L.; Peng, W.; You, L. X.; Wang, Z.

    2015-09-21

    In this research, we systematically investigated the superconducting properties and chemical composition of NbTiN thin films prepared on single-crystal MgO substrates. The NbTiN thin films with different thicknesses (4–100 nm) were deposited by reactive DC magnetron sputtering at ambient temperature. We measured and analyzed the crystal structure and thickness dependence of the chemical composition using X-ray diffraction and X-ray photoelectron spectroscopy depth profiles. The films exhibited excellent superconducting properties, with a high superconducting critical temperature of 10.1 K, low resistivity (ρ{sub 20} = 93 μΩ cm), and residual resistivity ratio of 1.12 achieved for 4-nm-thick ultrathin NbTiN films prepared at the deposition current of 2.4 A. The stoichiometry and electrical properties of the films varied gradually between the initial and upper layers. A minimum ρ{sub 20} of 78 μΩ cm and a maximum residual resistivity ratio of 1.15 were observed for 12-nm-thick films, which significantly differ from the properties of NbN films with the same NaCl structure.

  2. Polyimide/Carbon Nanotube Composite Films for Electrostatic Charge Mitigation

    NASA Technical Reports Server (NTRS)

    Smith, Joseph G., Jr.; Delozier, Donavon M.; Connell, John W.; Watson, Kent A.

    2004-01-01

    Low color, space environmentally durable polymeric films with sufficient electrical conductivity to mitigate electrostatic charge (ESC) build-up have potential applications on large, deployable, ultra-light weight Gossamer spacecraft as thin film membranes on antennas, solar sails, thermal/optical coatings, multi-layer insulation blankets, etc.. The challenge has been to develop a method to impart robust electrical conductivity into these materials without increasing solar absorptivity (alpha ) or decreasing optical transparency or film flexibility. Since these spacecraft will require significant compaction prior to launch, the film portion of the spacecraft will require folding. The state-of-the-art clear, conductive coating (e.g. indium-tin-oxide, ITO) is brittle and cannot tolerate folding. In this report, doping a polymer with single-walled carbon nanotubes (SWNTs) using two different methods afforded materials with good flexibility and surface conductivities in the range sufficient for ESC mitigation. A coating method afforded materials with minimal effects on the mechanical, optical, and thermo-optical properties as compared to dispersal of SWNTs in the matrix. The chemistry and physical properties of these nanocomposites are discussed.

  3. Temperature dependence of the biaxial modulus, intrinsic stress and composition of plasma deposited silicon oxynitride films

    NASA Technical Reports Server (NTRS)

    Harding, David R.; Ogbuji, Linus U. T.; Freeman, Mathieu J.

    1995-01-01

    Silicon oxynitride films were deposited by plasma-enhanced chemical-vapor deposition. The elemental composition was varied between silicon nitride and silicon dioxide: SiO(0.3)N(1.0), SiO(0.7)N(1.6), SiO(0.7)N(1.1), and SiO(1.7)N(0.%). These films were annealed in air, at temperatures of 40-240 C above the deposition temperature (260 C), to determine the stability and behavior or each composition. the biaxial modulus, biaxial intrinsic stress, and elemental composition were measured at discrete intervals within the annealing cycle. Films deposited from primarily ammonia possessed considerable hydrogen (up to 38 at.%) and lost nitrogen and hydrogen at anneal temperatures (260-300 C) only marginally higher than the deposition temperature. As the initial oxygen content increased a different mechanism controlled the behavior or the film: The temperature threshold for change rose to approximately equal to 350 C and the loss of nitrogen was compensated by an equivalent rise in the oxygen content. The transformation from silicon oxynitride to silica was completed after 50 h at 400 C. The initial biaxial modulus of all compositions was 21-3- GPa and the intrinsic stress was -30 to 85 MPa. Increasing the oxygen content raised the temperature threshold where cracking first occurred; the two film compositions with the highest initial oxygen content did not crack, even at the highest temperature (450 C) investigated. At 450 C the biaxial modulus increased to approximately equal to 100 GPa and the intrinsic stress was approximately equal to 200 MPa. These increases could be correlated with the observed change in the film's composition. When nitrogen was replaced by oxygen, the induced stress remained lower than the biaxial strength of the material, but, when nitrogen and hydrogen were lost, stress-relieving microcracking occurred.

  4. Growth of multi-component alloy films with controlled graded chemical composition on sub-nanometer scale

    DOEpatents

    Bajt, Sasa; Vernon, Stephen P.

    2005-03-15

    The chemical composition of thin films is modulated during their growth. A computer code has been developed to design specific processes for producing a desired chemical composition for various deposition geometries. Good agreement between theoretical and experimental results was achieved.

  5. Properties of polyvinyl alcohol/xylan composite films with citric acid.

    PubMed

    Wang, Shuaiyang; Ren, Junli; Li, Weiying; Sun, Runcang; Liu, Shijie

    2014-03-15

    Composite films of xylan and polyvinyl alcohol were produced with citric acid as a new plasticizer or a cross-linking agent. The effects of citric acid content and polyvinyl alcohol/xylan weight ratio on the mechanical properties, thermal stability, solubility, degree of swelling and water vapor permeability of the composite films were investigated. The intermolecular interactions and morphology of composite films were characterized by FTIR spectroscopy and SEM. The results indicated that polyvinyl alcohol/xylan composite films had good compatibility. With an increase in citric acid content from 10% to 50%, the tensile strength reduced from 35.1 to 11.6 MPa. However, the elongation at break increased sharply from 15.1% to 249.5%. The values of water vapor permeability ranged from 2.35 to 2.95 × 10(-7)g/(mm(2)h). Interactions between xylan and polyvinyl alcohol in the presence of citric acid become stronger, which were caused by hydrogen bond and ester bond formation among the components during film forming.

  6. Conductive thin-film composite hydrogels: Trapping an anionic polyelectrolyte in a polyaziridine host matrix

    SciTech Connect

    Wexler, A.; Suen, C.; Hill, S.

    1995-08-01

    Acid-catalyzed polymerization of sufficiently concentrated aqueous solutions of a trifunctional aziridine monomer affords hydrogels. Dynamic mechanical analysis has been used to demonstrate that composite hydrogels, obtained when the polymerization is effected in the presence of poly(sodium styrenesulfonate), have a composition dependent modulus. A region rich in the polyelectrolyte has a modulus which exceeds that of the {open_quotes}host{close_quotes} homogeneous polyaziridine hydrogel. This is consistent with ionic bonds between protonated sites on the polyaziridine matrix and sulfonate groups on the included polyelectrolyte augmenting the structural stability of the hydrogel. Thin films were prepared from coatings of the incipient hydrogel solutions. When the coatings are dried to a water content of 20%, water-insoluble thin films are obtained provided a critical weight fraction of the monomer is exceeded. Conductive thin films can be obtained, provided a critical weight fraction of polyelectrolyte is exceeded. FTIR analysis of the coatings in the attenuated total reflectance mode shows that conductivity increases as tight ion pairing decreases between the polyelectrolyte and its counter ions in the matrix. The S-shaped dependence of the normalized conductivity on the composition of the thin films is independent of the state of hydration of the film. Effective medium percolation theory, (EMPT), generally fits the S-shaped compositional dependence of the conductivity but overestimates the rate of growth of the conductivity beyond the critical point. 20 refs., 7 figs.

  7. Carbon nanodots-chitosan composite film: a platform for protein immobilization, direct electrochemistry and bioelectrocatalysis.

    PubMed

    Sheng, Meili; Gao, Yue; Sun, Junyong; Gao, Feng

    2014-08-15

    A novel composite film based on carbon nanodots (CNDs) and chitosan was readily prepared and used as immobilization matrix to entrap a heme protein, hemoglobin (Hb) for direct electrochemistry and bioelectrocatalysis. A modified electrode was obtained by casting Hb-CNDs-chitosan composites on the glassy carbon (GC) electrode surface. Spectroscopic and electrochemical studies showed that Hb entrapped in the composite film remained in its native structures, and CNDs in the film can greatly facilitate DET between the protein and the GC electrode. The electron-transfer kinetics of Hb in composite film was qualitatively evaluated by using the Marcus theory, and the apparent heterogeneous electron-transfer rate constant (ks) was estimated to be 2.39(±0.03)s(-1) with Laviron equations. The modified electrode showed excellent electrocatalytic behavior to the substrate, hydrogen peroxide (H2O2). The linear current response for H2O2 was from 1×10(-6) to 1.18×10(-4)M with a detection limit of 0.27(±0.02)μM at the signal-to-noise ratio of 3, and the apparent Michaelis-Menten constant was 0.067(±0.02)mM. These important features of CNDs-chitosan film have implied to be a promising platform for elaborating bioelectrochemical devices such as biosensors and biofuel cells. PMID:24681154

  8. Synthesis, characterization and low temperature electrical conductivity of Polyaniline/NiFe2O4 nanocomposites

    NASA Astrophysics Data System (ADS)

    Prasanna, G. D.; Prasad, V. B.; Jayanna, H. S.

    2015-02-01

    Conducting polymer/ferrite nanocomposites with an organized structure provide a new functional hybrid between organic and inorganic materials. The most popular among the conductive polymers is the polyaniline (PANI) due to its wide application in different fields. In the present work nickel ferrite (NiFe2O4) nanoparticles were prepared by sol-gel citrate-nitrate method with an average size of 21.6nm. PANI/NiFe2O4 nanoparticles were synthesized by a simple general and inexpensive in-situ polymerization in the presence of NiFe2O4 nanoparticles. The effects of NiFe2O4 nanoparticles on the dc-electrical properties of polyaniline were investigated. The structural components in the nanocomposites were identified from Fourier Transform Infrared (FTIR) spectroscopy. The crystalline phase of nanocomposites was characterized by X-Ray Diffraction (XRD). The Scanning Electron Micrograph (SEM) reveals that there was some interaction between the NiFe2O4 particles and polyaniline and the nanocomposites are composed of polycrystalline ferrite nanoparticles and PANI. The dc conductivity of polyaniline/NiFe2O4 nanocomposites have been measured as a function of temperature in the range of 80K to 300K. It is observed that the room temperature conductivity cRT decreases with increase in the relative content of NiFe2O4. The experimental data reveals that the resistivity increases for all composites with decrease of temperature exhibiting semiconductor behaviour.

  9. The preparation and characterization of nanoparticle Ag-SiO2 composite films with super low refractive index

    NASA Astrophysics Data System (ADS)

    Sun, Yu-Long; Wang, Jian; Li, Shou-Yi; He, Xin; Wang, Cheng-Wei

    2014-09-01

    The spin coating technique is used to prepare the porous Ag-SiO2 composite films, and the subsequent annealing process makes the nanoparticle Ag-SiO2 composite films formed. As the increase of the annealing temperature from 300 °C to 500 °C, the size of Ag-SiO2 composite nanoparticles gradually decreases. The SEM, TEM and XRD measurements of Ag-SiO2 composite films indicate that the single crystal metal nanoparticles are uniformly embedded into the SiO2 particles, forming Ag-SiO2 composite nanoparticles. The SPR absorption spectra of the Ag-SiO2 composite films show the content of metal Ag increases with the increase of annealing temperature, but when the annealing temperature increases to 500 °C, the SPR absorption is not observed on the absorption spectra although the total absorption of Ag-SiO2 composite films is enhanced. Furthermore, the optical constants of Ag-SiO2 composite films have been determined based on the measurement of ellipsometric parameters. It is more important the refractive index lower than 1 is obtained after annealing process of Ag-SiO2 composite films under 300 and 400 °C, but the extinction coefficient is low, which makes the film have low absorption.

  10. Poly(vinyl alcohol)/Liquid Crystal Composite Films with Low Driving Voltage

    NASA Astrophysics Data System (ADS)

    Ono, Hiroshi; Kawatsuki, Nobuhiro

    1994-12-01

    A poly(vinyl alcohol) (PVA)/liquid crystal (LC) composite film with a low driving voltage of 6 Vrms, a low hysteresis of less than 0.2 Vrms, and a fast response time of 11 ms at the operating voltage of 6 Vrms was formed from the emulsion composed of a mixture of water with methanol (WM-mixture), PVA, LC, and a photocrosslinkable mixture of nonaoxyethylenediacrylate (9EG-A) with perfluorooctylethylacrylate (FA-108). It was found in the composite film that the liquid crystal droplets, surrounded by a thin layer of the photocured polymer, were deformed as well as disordered, which enhanced light scattering.

  11. Improved thermal stability of polylactic acid (PLA) composite film via PLA-β-cyclodextrin-inclusion complex systems.

    PubMed

    Byun, Youngjae; Rodriguez, Katia; Han, Jung H; Kim, Young Teck

    2015-11-01

    The effects of the incorporation of PLA-β-cyclodextrin-inclusion complex (IC) and β-cyclodextrin (β-CD) on biopolyester PLA films were investigated. Thermal stability, surface morphology, barrier, and mechanical properties of the films were measured at varying IC (1, 3, 5, and 7%) and β-CD (1 and 5%) concentrations. The PLA-IC-composite films (IC-PLA-CFs) showed uniform morphological structure, while samples containing β-CD (β-CD-PLA-CFs) showed high agglomeration of β-CD due to poor interfacial interaction between β-CD and PLA moieties. According to the thermal property analysis, the 5% IC-PLA-CFs showed 6.6 times lower dimensional changes (6.5%) at the temperature range of 20-80°C than that of pure PLA film (43.0%). The increase of IC or β-CD content in the PLA-composite films shifted the glass transition and crystallization temperature to higher temperature regions. The crystallinity of both composite films improved by increasing IC or β-CD content. Both composite films had higher oxygen and water vapor permeability as IC or β-CD content increased in comparison to pure PLA film. All the composite films had less flexibility and lower tensile strength than the pure PLA film. In conclusion, this study shows that the IC technique is valuable to improve the thermal expansion stability of PLA-based films.

  12. Improved thermal stability of polylactic acid (PLA) composite film via PLA-β-cyclodextrin-inclusion complex systems.

    PubMed

    Byun, Youngjae; Rodriguez, Katia; Han, Jung H; Kim, Young Teck

    2015-11-01

    The effects of the incorporation of PLA-β-cyclodextrin-inclusion complex (IC) and β-cyclodextrin (β-CD) on biopolyester PLA films were investigated. Thermal stability, surface morphology, barrier, and mechanical properties of the films were measured at varying IC (1, 3, 5, and 7%) and β-CD (1 and 5%) concentrations. The PLA-IC-composite films (IC-PLA-CFs) showed uniform morphological structure, while samples containing β-CD (β-CD-PLA-CFs) showed high agglomeration of β-CD due to poor interfacial interaction between β-CD and PLA moieties. According to the thermal property analysis, the 5% IC-PLA-CFs showed 6.6 times lower dimensional changes (6.5%) at the temperature range of 20-80°C than that of pure PLA film (43.0%). The increase of IC or β-CD content in the PLA-composite films shifted the glass transition and crystallization temperature to higher temperature regions. The crystallinity of both composite films improved by increasing IC or β-CD content. Both composite films had higher oxygen and water vapor permeability as IC or β-CD content increased in comparison to pure PLA film. All the composite films had less flexibility and lower tensile strength than the pure PLA film. In conclusion, this study shows that the IC technique is valuable to improve the thermal expansion stability of PLA-based films. PMID:26299710

  13. Three-dimensional microporous polypyrrole/polysulfone composite film electrode for supercapacitance performance

    NASA Astrophysics Data System (ADS)

    Feng, Xiaojuan; Shi, Yanlong; Jin, Shuping

    2015-10-01

    The three-dimensional microporous polypyrrole/polysulfone (PPY/PSF) composite film was fabricated via a simple polymerization method. The morphology structure and chemical composition of the composite film were characterized by scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR), respectively. The electrochemical properties of the composite film electrode were evaluated by cyclic voltammetry, galvanostatic charging-discharging and electrochemical impedance spectroscopy. The material exhibits excellent capacitance performance including high capacitance of 500 F g-1 at 0.3 A g-1 current density, good cycle stability in 800 continuous cycles (only 4.5% decay after 800 cycles at 0.3 A g-1), and low inter resistance. The good property of the PPY/PSF electrode should be attributed to its structural features, including two-layer microporous structure which facilitates the penetration of electrolytes into the inner surface, high surface area which provides more active sites. These results show that the composite film is a promising candidate for high energy electrochemical capacitors.

  14. Fiber optic humidity sensor based on the graphene oxide/PVA composite film

    NASA Astrophysics Data System (ADS)

    Wang, Youqing; Shen, Changyu; Lou, Weimin; Shentu, Fengying

    2016-08-01

    Fiber optic humidity sensor based on an in-fiber Mach-Zehnder interferometer (MZI) coated with graphene oxide (GO)/PVA composite film was investigated. The MZI is constructed of two waist-enlarged tapers. The length between two waist-enlarged tapers is 20 mm. By comparing the experiment results of MZI coated with different GO/PVA composite films, composite film formed by the ratio of 0.3 g PVA mixed with 10 ml GO dispersion shows a better performance of relative humidity sensing. By using the molecular structure model of the composited GO/PVA, the operation mechanism between GO/PVA composite film and water molecules was illustrated. The sensitivity of 0.193 dB/%RH with a linear correlation coefficient of 99.1% and good stability under the relative humidity range of 25-80% was obtained. Temperature effect on the proposed fiber optic humidity sensor was also considered and analyzed. According to the repetitive experimental results, the proposed humidity sensor shows a good repeatability.

  15. Preparation of sensitive and recyclable porous Ag/TiO2 composite films for SERS detection

    NASA Astrophysics Data System (ADS)

    Zhang, Zhengyi; Yu, Jiajie; Yang, Jingying; Lv, Xiang; Wang, Tianhe

    2015-12-01

    Porous Ag/TiO2 composite films were prepared by spin coating of titania on normal glass slides and subsequent photochemical deposition of silver nanoparticles (AgNPs). The films were characterized by XRD and FESEM to reveal micro structural and morphological differences between films obtained under varied conditions. The SERS properties of these films were investigated using aqueous crystal violet (CV) as probe molecules. The results indicate that the content of polyethylene glycol (PEG) and photo-reduction time had significant influences on both the microstructure and SERS performance of Ag/TiO2 films. The highest SERS sensitivity that allowed as low as 10-10 M aqueous CV to be detected, was achieved with the PEG/(C4H9O)4Ti molar ratio being 0.08% and with 30 min of UV irradiation. With this film a linear relationship was established through experiment between SERS intensity and CV concentration from 10-10 to 10-5 M, which could be used as a calibration curve for CV concentration measurement. In addition, the film could be reused as a SERS substrate for up to four times without significantly losing SERS sensitivity if a simple regeneration was followed. It is visualized that the Ag/TiO2 film on glass has potentials for being developed into a practical SERS substrate with high sensitivity and good reusability.

  16. Chitosan and polyvinyl alcohol composite films containing nitrofurazone: preparation and evaluation

    PubMed Central

    Kouchak, Maryam; Ameri, Abdolghani; Naseri, Basireh; Kargar Boldaji, Sara

    2014-01-01

    Objective(s): The aim of this study was to insert nitrofurazone in a chitosan membrane to be used as a wound dressing. Materials and Methods: Several blend films using chitosan (Cs) and polyvinyl alcohol (PVA), containing nitrofurazone were prepared by means of casting/solvent evaporating technique. Different characteristics such as mechanical properties, water vapor transmission rate (WVTR), oxygen permeability (OP), swelling ability (SW), differential scanning calorimetric (DSC), drug release profiles and antibacterial activity of the films were investigated. Results: The results showed that nitrofurazone decreased tensile strength, OP and SW of Cs films, while increased WVTR. Addition of PVA at any concentration improved mechanical properties, reduced WVTR, and increased OP and SW of nitrofurazone-loaded Cs films. The latter films showed higher activity against Pseudomonas aeruginosa than drug-free chitosan films. Conclusion: The presence of PVA improves many properties of Cs-nitrofurazone films and makes them more desirable as dressing material for burn wounds. Although nitrofurazone alone is ineffective against P. aeruginosa, it is able to increase antibacterial effect of chitosan in composite films. PMID:24592302

  17. Temperature controlled junction behavior of polyaniline/ZnO heterostructures

    NASA Astrophysics Data System (ADS)

    Dhingra, Mansi; Shrivastava, Sadhna; Asokan, K.; Annapoorni, S.

    2016-05-01

    Organic-Inorganic hybrid materials have remained an active field of research both from the point of understanding the interfaces and for device purpose. In the present work, Zinc Oxide (ZnO) - Polyaniline (PANI) interface obtained by drop casting PANI nanofibres on sputtered ZnO thin film is investigated. The study of layer by layer deposition of organic and inorganic materials to form interface, is a very important issue related to carrier transport, charge separation, structural connectivity and interfacial defects. I-V characteristics were performed for different thickness of the underlying ZnO layer. The effect of temperature on the I-V characteristics is also investigated. Hall measurements were performed to estimate the charge carrier concentration of the n-ZnO and the p-PANI. Morphology and thickness of the interface was studied using SEM imaging technique. These interfaces could be explored for different applications in areas like sensors and optoelectronics.

  18. Synthesis and characterization of polyaniline as emeraldine salt

    NASA Astrophysics Data System (ADS)

    Gawri, Isha; Khatta, Swati; Singh, K. P.; Tripathi, S. K.

    2016-05-01

    Polyaniline in emeraldine salt (PANI-ES) form was successfully synthesized by oxidative polymerization of aniline using ammonium peroxidisulphate as oxidant in the presence of hydrochloric acid as catalyst under ice bath condition. The as prepared powdered sample was characterized using X-Ray Diffraction (XRD) and Fourier Transform Infrared (FTIR) spectroscopy. Using XRD, the average crystalline size was found to be 5.63 nm and d-spacing corresponding to crystalline peak 2θ = 25.08° had come out to be 4.2 Å. Also FTIR absorption spectra showed all the characteristics bands of PANI -ES. The ohmic contact between the PANI-ES film and the substrate was confirmed by Current-Voltage (I-V) characterization.

  19. Ordered micro/mesoporous composite prepared as thin films.

    PubMed

    Petkov, N; Hölzl, M; Metzger, T H; Mintova, S; Bein, T

    2005-03-17

    A new synthesis method for preparation of thin films and powders consisting of zeolite beta nanocrystals embedded in ordered mesoporous silica matrix is described. The final structures possessing bimodal porosity, i.e., high degree of mesophase order and spatially defined microporous zeolite nanocrystals are obtained via simultaneous solvent evaporation of preformed silica/surfactant/ethanol/nanosized zeolite beta assemblies. The films were characterized with grazing-incident diffraction (GID), nitrogen sorption based on gravimetric measurements with quartz crystal microbalance (QCM) devices, and transmission electron microscopy (TEM). It is shown that the incorporation of beta nanocrystals in the mesoporous silica matrix and the mesophase order itself can be controlled through the variation of the fractional amounts of the zeolite nanoparticles and silica/surfactant solutions. The HR-TEM measurements showed that the nanosized Beta microporous crystals are separated and at the same time connected through an ordered mesostructured matrix.

  20. Polyimide/Carbon Nanotube Composite Films for Electrostatic Charge Mitigation

    NASA Technical Reports Server (NTRS)

    Delozier, D. M.; Tigelaar, D. M.; Watson, K. A.; Smith, J. G., Jr.; Lillehei, P. T.; Connell, J. W.

    2004-01-01

    Low color, space environmentally durable polymeric films with sufficient electrical conductivity to mitigate electrostatic charge build-up have been under investigation as part of a materials development activity. In the work described herein, single-walled carbon nanotubes (SWNT) solutions were dispersed in solutions of a novel ionomer in N,N-dimethylacetamide resulting in homogenous suspensions or quasi-solutions. The ionomer was used to aid in the dispersal of SWNTs in to a soluble, low color space environmentally durable polyimide. The use of the ionomer as a dispersant enabled the nanotubes to be dispersed at loading levels up to 3 weight % in a polyimide solution without visual agglomeration. The films were further characterized for their electrical and mechanical properties.

  1. A study on photocatalytic activity of micro-arc oxidation TiO2 films and Ag+/MAO-TiO2 composite films

    NASA Astrophysics Data System (ADS)

    Xiang, N.; Song, R. G.; Xiang, B.; Li, H.; Wang, Z. X.; Wang, C.

    2015-08-01

    First, micro-arc oxidation (MAO) TiO2 films have been prepared on pure titanium in a phosphate-based electrolyte, and then the Ag+/MAO-TiO2 composite films have been fabricated by Ag+ impregnation in this paper. The microstructure and composition of MAO-TiO2 films and Ag+/MAO-TiO2 composite films have been studied by means of scanning electron microscopy (SEM), X-ray diffraction (XRD), and energy-dispersive X-ray spectroscopy (EDS). The photocatalytic activity of both films was evaluated by photocatalytic decolorization of methylene blue (MB) in aqueous solution as a model pollutant under sunlight irradiation simulation with homemade ultraviolet-visible spectroscopy (UV-vis). The results showed that the photocatalytic activity of MAO-TiO2 films increased with increasing the applied voltage and concentration in a certain scope. The morphology of Ag+/MAO-TiO2 composite films were of significantly difference and superior photocatalytic activity compared to the MAO-TiO2 film. Also, Ag+ impregnation was able to enhance the photocatalytic efficiency of MAO-TiO2 film.

  2. Composition and resistivity changes of reactively sputtered W-Si-N thin films under vacuum annealing

    SciTech Connect

    Vomiero, A.; Boscolo Marchi, E.; Mariotto, G.; Quaranta, A.; Della Mea, G.; Ottaviani, G.; Tonini, R.; Butturi, M.; Martinelli, G.

    2006-01-16

    W-Si-N layers about 200 nm thick with different nitrogen content were reactively sputtered from a W{sub 5}Si{sub 3} target on oxidized silicon substrates. The thermal stability of the films' composition and resistivity was studied with ion beam analysis and four-point probe measurements. Upon vacuum annealing from 600 to 980 deg. C for 1.5 h, a sample with an initial 56 at. % of nitrogen gradually loses nitrogen down to 36%. This composition lies close to the W-Si{sub 3}N{sub 4} tie line. Concurrently, the room temperature resistivity decreases from 4.7 to about 2 m{omega} cm. The composition changes only a little for a sample whose initial composition is near the W-Si{sub 3}N{sub 4} tie line and the resistivity changes significantly less than for the nitrogen-rich film. Interpretations are discussed.

  3. High-throughput combinatorial study of local stress in thin film composition spreads.

    PubMed

    Woo, Noble C; Ng, Bryan G; van Dover, R Bruce

    2007-07-01

    We investigate the stresses in thin films with sub-millimeter lateral spatial resolution using a dense array of prefabricated cantilever beams prepared by microelectromechanical-system techniques. Stress induced deflection of the cantilever is interrogated by an optical (laser/position sensitive detector) measurement system. Composition spread films are deposited on the cantilever array using a three gun on-axis magnetron cosputtering system. The position dependent composition is inferred using rate calibrations and verified by electron microprobe/energy dispersive spectroscopy. We demonstrate the function of this system using an Fe-Ni-Al composition spread with approximately 1 at. % resolution. This approach allows for measurement of the composition dependence of other electromechanical properties such as the martensitic phase transition temperature of traditional and ferromagnetic shape-memory alloys, as well as the properties of hydrogen storage materials and the magnetic response of magnetostrictive materials.

  4. Determination of uric acid level by polyaniline and poly (allylamine): Based biosensor.

    PubMed

    Wathoni, Nasrul; Hasanah, Aliya Nur; Gozali, Dolih; Wahyuni, Yeni; Fauziah, Lia Layusa

    2014-01-01

    The uric acid biosensor has been much developed by immobilizing uricase enzyme into the membrane of conductive polymer and the membrane of polyelectrolyte such as polyaniline (PANI) and poly (allylamine) (PAA) respectively. The purpose of this research was to create a new amperometric uric acid biosensor by immobilization of uricase in combination between PANI and PAA membranes. The working electrode was Pt plate (0.5 mm). The auxiliary and the reference electrode were Pt wire 0.4 mm and Ag/AgCl respectively. Uricase, uric acid, PAA, pyrrole and glutaraldehyde were supplied from Sigma. All other chemical was obtained from Merck. The biosensor was created by immobilizing of uricase by a glutaraldehyde crosslinking procedure on PANI composite film on the surface of a platinum electrode while the polyelectrolyte layer of PAA were prepared via layer-by-layer assembly on the electrode, functioning as H2O2-selective film. Standard of deviation, coefficient of variation (CV) and coefficient of correlation (r) analysis were used in this study. The biosensor had a good linearity with a correlation coefficient of 0.993 and it could be used up to 27 times with the CV value of 3.97%. The presence of other compounds such as glucose and ascorbic acid gave 1.3 ± 1.13% and 3.27 ± 2.29% respectively on the interference effect toward the current response of uric acid biosensor. The polymer combination of PANI and PAA can be used as a selective matrix of uric acid biosensor. PMID:24696812

  5. Determination of uric acid level by polyaniline and poly (allylamine): Based biosensor

    PubMed Central

    Wathoni, Nasrul; Hasanah, Aliya Nur; Gozali, Dolih; Wahyuni, Yeni; Fauziah, Lia Layusa

    2014-01-01

    The uric acid biosensor has been much developed by immobilizing uricase enzyme into the membrane of conductive polymer and the membrane of polyelectrolyte such as polyaniline (PANI) and poly (allylamine) (PAA) respectively. The purpose of this research was to create a new amperometric uric acid biosensor by immobilization of uricase in combination between PANI and PAA membranes. The working electrode was Pt plate (0.5 mm). The auxiliary and the reference electrode were Pt wire 0.4 mm and Ag/AgCl respectively. Uricase, uric acid, PAA, pyrrole and glutaraldehyde were supplied from Sigma. All other chemical was obtained from Merck. The biosensor was created by immobilizing of uricase by a glutaraldehyde crosslinking procedure on PANI composite film on the surface of a platinum electrode while the polyelectrolyte layer of PAA were prepared via layer-by-layer assembly on the electrode, functioning as H2O2-selective film. Standard of deviation, coefficient of variation (CV) and coefficient of correlation (r) analysis were used in this study. The biosensor had a good linearity with a correlation coefficient of 0.993 and it could be used up to 27 times with the CV value of 3.97%. The presence of other compounds such as glucose and ascorbic acid gave 1.3 ± 1.13% and 3.27 ± 2.29% respectively on the interference effect toward the current response of uric acid biosensor. The polymer combination of PANI and PAA can be used as a selective matrix of uric acid biosensor. PMID:24696812

  6. Fluorine-containing composition for forming anti-reflection film on resist surface and pattern formation method

    DOEpatents

    Nishi, Mineo; Makishima, Hideo

    1996-01-01

    A composition for forming anti-reflection film on resist surface which comprises an aqueous solution of a water soluble fluorine compound, and a pattern formation method which comprises the steps of coating a photoresist composition on a substrate; coating the above-mentioned composition for forming anti-reflection film; exposing the coated film to form a specific pattern; and developing the photoresist, are provided. Since the composition for forming anti-reflection film can be coated on the photoresist in the form of an aqueous solution, not only the anti-reflection film can be formed easily, but also, the film can be removed easily by rinsing with water or alkali development. Therefore, by the pattern formation method according to the present invention, it is possible to form a pattern easily with a high dimensional accuracy.

  7. EPR, charge transport, and spin dynamics in doped polyanilines

    NASA Astrophysics Data System (ADS)

    Kon'kin, A. L.; Shtyrlin, V. G.; Garipov, R. R.; Aganov, A. V.; Zakharov, A. V.; Krinichnyi, V. I.; Adams, P. N.; Monkman, A. P.

    2002-08-01

    Charge transport and magnetic properties of films of polyaniline (PAN) doped with 10-camphorsulfonic acid and 2-acrylamido-2-methyl-1-propanesulfonic acid (AMPSA) have been studied by conductivity, magnetic-susceptibility superconducting quantum interference device measurements, and 3-cm and 8-mm electron paramagnetic resonance (EPR) spectroscopy at doping levels (x) from 0.3 to 0.9 over a temperature range from 15 to 300 K. The temperature dependences of conductivities were explained in terms of the advanced multiphase heterogeneous granular metallic (HGM) model with percolation including disordered metallic (DM) and nonmetallic (NM) phases. The anomalous conductivity change in the PAN-AMPSAx system at T>240 K was accounted quantitatively for a solid-phase equilibrium with the occurrence of the disordered anion phase from the metallic islands. A means for analysis of the EPR line shape in conducting media has been developed and, with this, conductivity and microwave dielectric constants were estimated and two EPR signals, R1 and R2, were detected in both systems. It was shown that R1 signal belongs to pinned radicals of isolated polymer chains, whereas R2 is the weight-averaged signal, resulting from three types of paramagnetic centers, localized and mobile spins in the NM and DM phases, which interact via exchange. From the temperature and frequency dependences of the R2 linewidth the spin-diffusion parameters for the NM phase in both systems were determined. It was found that the HGM model allows good explanation of both charge transport and spin diffusion in the doped polyaniline films.

  8. Synthesis of nanoparticles and nanofibers of polyaniline by potentiodynamic electrochemical polymerization.

    PubMed

    Xavier, Miguel G; Venancio, Everaldo C; Pereira, Ernesto C; Leite, Fabio L; Leite, Edson R; MacDiarmid, Alan G; Mattoso, L H C

    2009-03-01

    Potentiodynamic electrochemical synthesis was used to controllably synthesize nanofibers (mean diameter 48 nm) and/or nanoparticles (mean diameter 88 nm) of polyaniline (PANI) on gold electrodes. The films were characterized by cyclic voltammetry (CV), field emission gun scanning electron microscopy (FEG-SEM) and atomic force microscopy (AFM). The type and dimensions of the nanostructures depend on deposition conditions such as monomer concentration and scan rate. This study shows that the nucleation and growth steps play a key role on the film development and its nano-morphology.

  9. Surface plasmon resonance response of Au-WO3- x composite films

    NASA Astrophysics Data System (ADS)

    Chen, Bo; Yang, Dongfang; Lin, Chii-Wann

    2009-11-01

    Surface plasmon resonance of metal-dielectric composite thin films formed by noble metal nanoparticles embedded in a dielectric matrix offers a high degree of flexibility and enables many applications such as surface enhanced spectroscopes, and biological and chemical sensing. In this article, Au-WO3- x composite films of various Au contents and thicknesses were prepared by the pulsed laser deposition technique, and their SPR responses were measured in the Kreschmann geometry, using a polarized light beam at 640 nm wavelength. Theoretical calculation of SPR responses based on the Bruggeman or Maxwell-Garnett model with the MacLeod general characteristic matrix method is in obvious discrepancy with experimental measurements but it is able to predict the trend in term of the dependence of SPR responses on Au content and thickness of the Au-WO3- x films. The SPR responses of the Au-WO3- x films when exposed to NO gas molecules were measured and the preliminary results indicated that gas sensing using the SPR responses of metal-dielectric composite films is feasible.

  10. Rapid composition analysis of compound semiconductor thin film solar cell by laser induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Lee, S. H.; Kim, C. K.; In, J. H.; Jeong, S. H.

    2014-03-01

    The characteristics of laser-induced breakdown spectroscopy (LIBS) such as short measurement time and no sample preparation provide clear advantages over other analytical techniques for rapid elemental analysis at manufacturing sites where the composition of products need to be determined in real-time for process monitoring or quality control. Thin film solar cells based on CuIn1-xGaxSe2 (CIGS), polycrystalline compound semiconductor material, have unique advantages of high efficiency (>20%), long-term stability, and low manufacturing cost over other types of solar cell. The electrical and optical properties of the thin CIGS films are closely related to the concentration ratios among its major constituent elements Cu, In, Ga and Se such as Ga/(Ga + In) and Cu/(Ga + In), and thus an accurate measurement of the composition of CIGS thin films has been an issue among CIGS solar cell researchers, requiring a fast and reliable technique for composition analysis. This paper presents the results of nanosecond (ns) and femtosecond (fs) laser based LIBS analysis of thin CIGS films. The critical issues for LIBS analysis of CIGS thin films such are discussed in comparison with ns- and fs-LIBS measurement results. The calibration of LIBS signal intensity ratios with respect to reference concentration data is carried out and the results of optimal line selection for LIBS analysis, depth profiling capability, and reproducibility are discussed.

  11. Mechanical and barrier properties of guar gum based nano-composite films.

    PubMed

    Saurabh, Chaturbhuj K; Gupta, Sumit; Bahadur, Jitendra; Mazumder, S; Variyar, Prasad S; Sharma, Arun

    2015-06-25

    Guar gum based nano-composite films were prepared using organically modified (cloisite 20A) and unmodified (nanofil 116) nanoclays. Effect of nanoclay incorporation on mechanical strength, water vapor barrier property, chromatic characteristics and opacity of films was evaluated. Nano-composites were characterized using X-ray scattering, FTIR and scanning electron microscopy. A nanoclay concentration dependent increase in mechanical strength and reduction in water vapor transmission rate was observed. Films containing nanofil 116 (2.5% w/w guar gum) and closite 20A (10% w/w guar gum) demonstrated a 102% and 41% higher tensile strength, respectively, as compared to the control. Lower tensile strength of cloisite 20A films as compared to nanofil 116 films was due to its incompatibility with guar gum. X-ray scattering analysis revealed that interstitial spacing between nanofil 116 and cloisite 20A sheets increased due to intercalation by guar gum polymer. This resulted in improved mechanical and barrier properties of nano-composites compared to control. PMID:25839796

  12. ZnO micro-nano composite hydrophobic film prepared by the three-step method

    NASA Astrophysics Data System (ADS)

    Ma, Kai; Li, Hua; Zhang, Han; Xu, Xiao-Liang; Gong, Mao-Gang; Yang, Zhou

    2009-05-01

    The hydrophobicity of the lotus leaf is mainly due to its surface micro-nano composite structure. In order to mimic the lotus structure, ZnO micro-nano composite hydrophobic films were prepared via the three-step method. On thin buffer films of SiO2, which were first fabricated on glass substrates by the sol-gel dip-coating method, a ZnO seed layer was deposited via RF magnetron sputtering. Then two different ZnO films, micro-nano and micro-only flower-like structures, were grown by the hydrothermal method. The prepared films have different hydrophobic properties after surface modification. The structures of the obtained ZnO films were characterized using x-ray diffraction and field-emission scanning electron microscopy. A conclusion that a micro-nano composite structure is more beneficial to hydrophobicity than a micro-only structure was obtained through research into the effect of structure on hydrophobic properties.

  13. Composition and growth procedure-dependent properties of electrodeposited CuInSe 2 thin films

    NASA Astrophysics Data System (ADS)

    Babu, S. Moorthy; Ennaoui, A.; Lux-Steiner, M. Ch.

    2005-02-01

    CuInSe 2 thin films were deposited on molybdenum-coated glass substrates by electrodeposition. Deposition was carried out with a variety of electrochemical bath compositions. The quality of the deposits depends very much on the source materials as well as the concentration of the same in the electrolyte. The deposition potential was varied from -0.4 to -0.75 V vs. SCE. The pH of the solution was adjusted to 1.5-2 using diluted sulphuric acid. Chloride salts containing bath yield good surface morphology, but there is always excess of the metallic content in the deposited films. Different growth procedures, like initial metallic layers of copper or indium, layers of copper selenide or indium selenide before the actual deposition of ternary chalcopyrite layers were attempted. Fabrication pathway, morphological and compositional changes due to the different precursor route has been analysed. The quality of the deposits prepared by one-step electrodeposition is better than the deposits with a two-stage process. The deposited films were characterized with XRD, SEM-EDAX, UV-visible spectroscopy and I- V characteristics. The deposited films were annealed in air as well as in nitrogen atmosphere. The influence of annealing temperature, environment and annealing time on the properties of the films are evaluated. Attempts were made to fabricate solar cell structure from the deposited absorber films. The structure of Mo/CuInSe 2/CdS/ZnO/Ni was characterized with surface, optical and electrical studies.

  14. The mechanism of Bi nanowire growth from Bi/Co immiscible composite thin films.

    PubMed

    Volobuev, Valentine V; Dziawa, Piotr; Stetsenko, Alexander N; Zubarev, Eugene N; Savitskiy, Boris A; Samburskaya, Tatyana A; Reszka, Anna; Story, Tomasz; Sipatov, Alexander Yu

    2012-11-01

    Single crystalline Bi nanowires were grown by extrusion from Bi/Co thin films. The films were obtained by thermal evaporation in high vacuum. The average diameter, length and density of obtained nanowires were 100 nm, 30 microm and 6.5 x 10(5) cm(-2), respectively. The non-catalyzed self-organized process of whisker formation on the surface of immiscible composite thin film was exploited for nanowire growth. It was shown that the whiskers had formed during and after a thin film deposition. The value of residual stresses in a whole thin film coating as well as in its bismuth component was measured using X-ray diffraction technique. It was revealed that local compressive stresses, that had induced the whisker growth, had been formed by a segregation of Bi layers into Bi globules. A simple model of the whisker formation to minimize free energy in the Bi/Co system was proposed taking into account interfacial and elastic deformation energies. The obtained results can be utilized for growing of nanowires of other low-melting-point metals and semiconductors from immiscible composite thin films. PMID:23421254

  15. Green synthesis of high conductivity silver nanoparticle-reduced graphene oxide composite films

    NASA Astrophysics Data System (ADS)

    Dinh, D. A.; Hui, K. S.; Hui, K. N.; Cho, Y. R.; Zhou, Wei; Hong, Xiaoting; Chun, Ho-Hwan

    2014-04-01

    A green facile chemical approach to control the dimensions of Ag nanoparticles-graphene oxide (AgNPs/GO) composites was performed by the in situ ultrasonication of a mixture of AgNO3 and graphene oxide solutions with the assistance of vitamin C acting as an environmentally friendly reducing agent at room temperature. With decreasing ultrasonication time, the size of the Ag nanoparticles decreased and became uniformly distributed over the surface of the GO nanosheets. The as-prepared AgNPs/rGO composite films were then formed using a spin coating method and reduced at 500 °C under N2/H2 gas flow for 1 h. Four-point probe measurements showed that the sheet resistance of the AgNPs/rGO films decreased with decreasing AgNPs size. The lowest sheet resistance of 270 Ω/sq was obtained in the film corresponding to 1 min of ultrasonication, which showed a 40 times lower resistivity than the rGO film (10.93 kΩ/sq). The formation mechanisms of the as-prepared AgNPs/rGO films are proposed. This study provides a guide to controlling the dimensions of AgNPs/rGO films, which might hold promise as advanced materials for a range of analytical applications, such as catalysis, sensors and microchips.

  16. Direct evidence for compositional fluctuation in sputtered Co-Cr thin films

    NASA Astrophysics Data System (ADS)

    Hono, K.; Maeda, Y.; Li, J.-L.; Sakurai, T.

    1992-05-01

    Nano-scale concentration fluctuations in sputtered Co-23 at% Cr magnetic thin films were analyzed by atom probe field ion microscopy (APFIM). The atom probe concentration depth profile obtained from the film which was deposited on the W tip at 200°C clearly showed that the composition fluctuated significantly. The concentration of the Cr enriched region was in the range of 30-40 at% Cr, while that of the Cr depleted region was in the range of 5-10 at% Cr. This result proves that compositional fluctuations are present inside the grains of the Co-Cr sputtered film as suggested by the TEM observation of the chrysanthemum-like pattern (CP) structure.

  17. Electrical and optical properties of ferric doped PVA-PVP-PPy composite films

    NASA Astrophysics Data System (ADS)

    Patil, Ravikumar V.; Ranganath, M. R.; Lobo, Blaise

    2013-02-01

    The analysis of experimental optical spectra & electrical properties of PVA-PVP-PPy composite films is discussed in this paper. The optical parameters like activation energy of optical transitions and the optical band gap for direct and indirect allowed transitions were determined for PVA-PVP-PPy composite films doped with different concentrations of ferric chloride. The optical band gap showed best fit for indirect allowed transitions, and there is a decrease in the optical band gap with increase in concentration of ferric chloride. The DC electrical properties of these films indicated agreement with Mott's Variable Range Hopping Model in three dimensions. The width of the forbidden band gap was determined from the Arrhenius relation after experimentally studying in-situ, the variation of DC electrical conductivity with temperature.

  18. Sensitive electrochemical detection of Salmonella with chitosan-gold nanoparticles composite film.

    PubMed

    Xiang, Cuili; Li, Ran; Adhikari, Bimalendu; She, Zhe; Li, Yongxin; Kraatz, Heinz-Bernhard

    2015-08-01

    An ultrasensitive electrochemical immunosensor for detection of Salmonella has been developed based on using high density gold nanoparticles (GNPs) well dispersed in chitosan hydrogel and modified glassy carbon electrode. The composite film has been oxidized in NaCl solution and used as a platform for the immobilization of capture antibody (Ab1) for biorecognition. After incubation in Salmonella suspension and horseradish peroxidase (HRP) conjugated secondary antibody (Ab2) solution, a sandwich electrochemical immunosensor has been constructed. The electrochemical signal was obtained and improved by comparing the composite film with chitosan film. The result has shown that the constructed sensor provides a wide linear range from 10 to 10(5) CFU/mL with a low detection limit of 5 CFU/mL (at the ratio of signal to noise, S/N=3:1). Furthermore, the proposed immunosensor has demonstrated good selectivity and reproducibility, which indicates its potential in the clinical diagnosis of Salmonella contaminations. PMID:26048833

  19. Preparation and characterization of graphene nano-platelets integrated polyaniline based conducting nanocomposites

    NASA Astrophysics Data System (ADS)

    Tokala, Mamata Reddy; Padya, Balaji; Jain, P. K.; Shilpa Chakra, C. H.

    2015-06-01

    Natural graphite flakes were intercalated with strong oxidizing agents and were converted into thermally expanded graphite (TEG) through thermal exfoliation. Thermally expanded graphite was delaminated and transformed into graphene nanoplatelets (GNP) by using ultrasonic irradiation. GNP integrated polyaniline (PANi) nanocomposites were synthesized via in-situ polymerization of aniline monomers in the presence of GNP. The structure and morphology of composite was evidenced by scanning electron microscopy, Transmission electron microscopy (TEM), X-ray diffraction and Raman spectroscopy. TEM micrographs revealed that GNP consists of 20-25 graphene layers and PANi was uniformly coated on GNP. From Raman analysis it was showed significant interactions between GNP and polyaniline. Electrical conductivity was measured by using 4-point probe device, enhanced conductivity was obtained for composite.

  20. Doped SnO₂ transparent conductive multilayer thin films explored by continuous composition spread.

    PubMed

    Lee, Jin Ju; Ha, Jong-Yoon; Choi, Won-Kook; Cho, Yong Soo; Choi, Ji-Won

    2015-04-13

    Mn-doped SnO₂ thin films were fabricated by a continuous composition spread (CCS) method on a glass substrate at room temperature to find optimized compositions. The fabricated materials were found to have a lower resistivity than pure SnO₂ thin films because of oxygen vacancies generated by Mn doping. As Mn content was increased, resistivity was found to decrease for limited doping concentrations. The minimum thin film resistivity was 0.29 Ω-cm for a composition of 2.59 wt % Mn-doped SnO₂. The Sn-O vibrational stretching frequency in FT-IR showed a blue shift, consistent with oxygen deficiency. Mn-doped SnO₂/Ag/Mn-doped SnO₂ multilayer structures were fabricated using this optimized composition deposited by an on-axis radio frequency (RF) sputter. The multilayer transparent conducting oxide film had a resistivity of 7.35 × 10⁻⁵ Ω-cm and an average transmittance above 86% in the 550 nm wavelength region. PMID:25761303