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Conductive polymer gas sensor for quantitative detection of methanol in Brazilian sugar-cane spirit

Peres, Laura O.; Li, Rosamaria W. C.; Yamauchi, Elaine Yuka; Lippi, Renata; Gruber, Jonas
Fonte: ELSEVIER SCI LTD; OXFORD Publicador: ELSEVIER SCI LTD; OXFORD
Tipo: Artigo de Revista Científica
ENG
Relevância na Pesquisa
68.07508%
A low-cost chemiresistive gas sensor is described, made by the deposition of a thin film of a conductive polymer, poly(2-dodecanoylsulfanyl-p-phenylenevinylene), doped with dodecylbenzenesulfonic acid (10%, w/w), onto interdigitated electrodes. The sensor exhibits linear electrical conductance changes in function of the concentration of methanol present in sugar-cane spirit in the range between 0.05% and 4.0%. Since the sensor is cheap, easy to fabricate, durable, presents low power consumption, and is not sensitive to ethanol, acetic acid or water, it can be used in portable equipments for monitoring methanol levels in distilled alcoholic beverages such as Brazilian sugar-cane spirit (cachaca). (C) 2011 Elsevier Ltd. All rights reserved.; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [06/59464-2]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) [303717/2010-6, 472297/2007-4]; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)

Síntese e aplicação de polímeros condutores em sensores olfativos; Synthesis and application of conductive polymers in olfactory sensors

Cordeiro, Juliana Ribeiro
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 25/02/2010 PT
Relevância na Pesquisa
47.910566%
Os objetivos do trabalho consistem em síntese e caracterização de três polímeros: poli(2,1,3-benzotiadiazol-4,7-ilenovinileno) (PBTDV), poli(2,1,3-benzotiadiazol-4,7-ilenovinileno-co-2-bromo-5-hexilóxi-p-fenilenovinileno (PBTDV-co-BHPPV) e poli(2-bromo-5-hexilóxi-p-fenilenovinileno) (BHPPV), sendo os dois primeiros inéditos; aplicação de polímeros condutores no desenvolvimento de um nariz eletrônico capaz de identificar madeiras; e aplicação de polímeros condutores em um sensor de pressão. Os polímeros foram preparados de maneira satisfatória via redução catódica de seus precursores tetra-halogenados, que forneceu produtos com rendimentos apreciáveis. Para o projeto do nariz eletrônico que pretende identificar madeiras, dois conjuntos de espécies de madeira foram estudadas: (a) mogno e cedro e (b) imbuia e canela-preta. O nariz eletrônico desenvolvido apresenta um conjunto de quatro sensores de gás, que foram construídos por meio da deposição de finos filmes de polímeros dopados sobre a superfície de eletrodos interdigitados. Esse conjunto de sensores foi desenvolvido com sucesso, sendo capaz de diferenciar as espécies de madeira com taxa de acerto de 100%. Por fim, foi desenvolvido também com sucesso um sensor de gás capaz de atuar como sensor de pressão. Esse dispositivo mostrou-se sensível à variação de pressão...

Síntese e aplicação de um poli(arenilenovinileno) derivado de [2,1,3]-benzotiadiazol, tiofeno e fluoreno em narizes eletrônicos e dispositivos magnetorresistivos; Synthesis and application of a poli(arylenevinylene) derived from [2,1,3]-benzothiadiazole, thiophene and fluorene in electronic noses and magnetoresistive devices

Esteves, Carlos Henrique Alves
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Dissertação de Mestrado Formato: application/pdf
Publicado em 01/02/2013 PT
Relevância na Pesquisa
47.956436%
O objetivo sintético do presente trabalho é a síntese, caracterização e aplicação do polímero conjugado inédito de baixa Egap, poli(9,9-n-dioctil-2,7-fluorenilenovinilenoalt- 4,7-dibenzotiadiazol-2,5-tiofeno) (PF-BTB). A rota sintética proposta envolve 10 passos, dentre os quais destacam-se reações como a de Wittig e acoplamentos de paládio (Stille e Heck). A caracterização da molécula envolveu as técnicas de RMN de 1H, espectroscopias de infravermelho, UV-VIS e fluorescência, voltametria cíclica, análises térmicas (TGA e DSC) e cromatografia por permeação em gel. A primeira aplicação do polímero se deu na construção de um nariz eletrônico capaz de identificar com ótima precisão três variedades de tabaco (Burley, Flue Cured e Oriental), além de oito diferentes marcas comerciais de cigarro. Esses estudos, além da aplicação prática, serviram para mostrar a eficiência de um tipo novo de sensor para narizes eletrônicos, composto por um mesmo polímero condutor dopado com diferentes porfirinas, denominado sensor híbrido. Por fim, filmes finos do polímero PF-BTB, depositados sobre eletrodos de ouro, tiveram suas propriedades magnetorresistivas testadas em diferentes condições, apresentando valores maiores que 40%...

Estudo de polímeros condutores iônicos e eletrônicos dopados com metais alcalinos utilizando-se espectroscopia de alta resolução em sólidos por ressonância magnética multinuclear; Ionic and electronic alkaline metal doped conductive polymer studies using high resolution multinuclear solid-state nuclear magnetic resonance

Giotto, Marcus Vinicius
Fonte: Biblioteca Digitais de Teses e Dissertações da USP Publicador: Biblioteca Digitais de Teses e Dissertações da USP
Tipo: Tese de Doutorado Formato: application/pdf
Publicado em 28/04/1997 PT
Relevância na Pesquisa
47.8552%
As técnicas de Espectroscopia de Alta Resolução em Sólidos e Relaxação por RMN são largamente utilizadas no estudo da estrutura e dinâmica de polímeros. Neste trabalho estudamos, utilizando estas técnicas, duas classes distintas de polímeros: os condutores iônicos e os condutores eletrônicos. O polímero condutor iônico estudado foi o Diesterato de Polietileno Glicol (PEGD) complexado com sais de metais alcalinos, LiClO4 ou NaClO4. A metodologia básica que empregamos para o estudo destes materiais foi a análise da forma de linha e do tempo de relaxação longitudinal para os núcleos associados tanto aos portadores de carga, 7Li e 23Na, quanto à cadeia polimérica, 1H e 13C. Todas estas medidas foram realizadas em função da temperatura e da concentração de sal de metal alcalino presente na amostra. Estudos adicionais, por condutividade elétrica, análise térmica e viscosidade foram realizados para complementar o conhecimento obtido por RMN sobre a mobilidade e estrutura das cadeias poliméricas e dos portadores de carga. Os polímeros com ligações de elétrons-'pi' conjugados apresentam propriedades eletrônicas especiais, particularmente a condutividade elétrica, e formam uma classe de polímeros condutores eletrônicos que podem ser facilmente oxidados ou reduzidos através de um agente dopante. Estudamos dois polímeros deste tipo: As polianilinas dopadas com 1H ou 7Li. A metodologia básica que empregamos para o estudo destes polímeros foi a análise das formas de linhas espectrais de um dos núcleos que compõem a cadeia polimérica...

A new method for extending the range of conductive polymer sensors for contact force

Carvalho, A. A.; Radwin, R. G.
Fonte: Elsevier B.V. Publicador: Elsevier B.V.
Tipo: Artigo de Revista Científica Formato: 285-290
ENG
Relevância na Pesquisa
48.07508%
This paper describes a technique for extending the force range of thin conductive polymer force sensors used for measuring contact force. These sensors are conventionally used for measuring force by changing electrical resistance when they are compressed. The new method involves measuring change in electrical resistance when the flexible sensor, which is sensitive to both compression and bending, is sandwiched between two layers of spring steel, and the structure is supported on a thin metal ring. When external force is applied, the stiffened sensor inside the spring steel is deformed within the annular center of the ring, causing the sensor to bend in proportion to the applied force. This method effectively increases the usable force range, while adding little in the way of thickness and weight. Average error for loads between 10 N and 100 N was 2.2 N (SD = 1.7) for a conventional conductive polymer sensor, and 0.9 N (SD = 0.4) using the new approach. Although this method permits measurement of greater loads with an error less than 1 N, it is limited since the modified sensor is insensitive to loads less than 5 N. These modified sensors are nevertheless useful for directly measuring normal force applied against handles and tools and other situations involving forceful manual work activities...

Thermal analysis of conductive blends of PVDF and poly(o-methoxyaniline)

Malmonge, L. F.; Mattoso, L. H C
Fonte: Universidade Estadual Paulista Publicador: Universidade Estadual Paulista
Tipo: Artigo de Revista Científica Formato: 8387-8391
ENG
Relevância na Pesquisa
48.31162%
The thermal behavior of blends of poly(vinylidene fluoride), or PVDF, and poly(o-methoxyaniline) doped with toluene sulfonic acid was studied by thermogravimetic analysis, electrical conductivity measurements, differential scanning calorimetry, X-ray diffraction and scanning electron microscopy. Blends with thermal and electrical conductivity stabler than the conductive polymer alone were obtained. Nevertheless, degradation occurs after a long period of time (500 h) at high temperatures. The possible association of the conductivity decay with dopant loss, degradation and structural and morphological changes of the blend is discussed. (C) 2000 Elsevier Science Ltd.; The thermal behavior of blends of poly(vinylidene fluoride), or PVDF, and poly(o-methoxyaniline) doped with toluene sulfonic acid was studied by thermogravimetic analysis, electrical conductivity measurements, differential scanning calorimetry, X-ray diffraction and scanning electron microscopy. Blends with thermal and electrical conductivity stabler than the conductive polymer alone were obtained. Nevertheless, degradation occurs after a long period of time (500 h) at high temperatures. The possible association of the conductivity decay with dopant loss, degradation and structural and morphological changes of the blend is discussed.

Síntese e caracterização elétrica de compósitos poliméricos condutores com o poliuretano derivado de óleo de mamona como matriz

Rebeque, Paulo Vinícius dos Santos
Fonte: Universidade Estadual Paulista (UNESP) Publicador: Universidade Estadual Paulista (UNESP)
Tipo: Dissertação de Mestrado Formato: 88 f. : il.
POR
Relevância na Pesquisa
48.55884%
Pós-graduação em Ciência dos Materiais - FEIS; Compósitos poliméricos condutores, também chamados de polímeros condutores extrínsecos, têm sido alvo de intensa pesquisa científica devido ao seu grande potencial de aplicação nos mais diversificados setores industriais. Esses materiais combinam as características de um polímero (leveza, flexibilidade, fácil processamento) com as de cargas condutoras (alta condutividade). O poliuretano derivado de óleo de mamona (PUR) é um polímero obtido pela mistura de pré-polímero e poliol (derivado de óleo de mamona) que apresenta grande potencial para ser utilizado como matriz polimérica em compósitos. Ele possui propriedades equivalentes aos dos poliuretanos (PU) convencionais e tem como vantagem ser um polímero biodegradável e proveniente de fonte renovável. Em relação às cargas condutoras, o negro de fumo (NF) é um dos materiais mais utilizados para esse fim, enquanto que pouco se encontra na literatura sobre o carvão ativado nano em pó (CANP), mesmo possuindo estrutura semelhante e maior condutividade que o NF. Neste contexto, o presente trabalho tem como objetivo viabilizar os processos de síntese e fazer a caracterização elétrica dos compósitos poliuretano derivado de óleo de mamona/carvão ativado nano em pó (PUR/CANP) e poliuretano derivado de óleo de mamona/negro de fumo (PUR/NF) na forma de filmes pelo método “casting”...

Effect of the processing conditions on the mechanical and electrical properties of extruded conductive PP tape and filament

Silva, Marco Aurélio Pinto; Martins, R. S.; Nóbrega, J. M.; Carvalho, Helder; Lanceros-Méndez, S.
Fonte: Sociedade Portuguesa de Materiais Publicador: Sociedade Portuguesa de Materiais
Tipo: Conferência ou Objeto de Conferência
Publicado em /04/2011 ENG
Relevância na Pesquisa
58.51953%
Polypropylene (PP) shows a number of desirable properties that make it a versatile material among thermoplastic polymers. Due to its low cost and density, it is an excellent resin for conductive polymer composites (CPCs).[1] CPCs mainly consist on a polymer matrix with incorporated carbonaceous fillers. These multifunctional materials are routinely employed in various commercial applications due to their good electrical conductivity, corrosion resistance, light weight and enhanced mechanical properties. [2] The filler content is the crucial aspect in conductive polymer composites fabrication: due to mechanical behaviour it must be as low as possible but enough to allow fulfilling the electrical requirements.[2] In this work commercial conductive master batch PP was extruded in the form of tape and filament using different processing conditions, namely different draw ratios and temperatures. In order to tailor the mechanical performance of the material, different several amounts of PP homopolymer were added to the commercial conductive resin. The results show that the amount of homopolymer directly influences mechanical and electrical performance of the material. Increasing homopolymer content yields a more stretchable, and mechanically resistant...

Production of electroactive filaments by coextrusion

Nóbrega, J. M.; Ferreira, A.; Costa, Pedro; Carvalho, Helder; Sencadas, V.; Lanceros-Méndez, S.
Fonte: Universidade do Minho Publicador: Universidade do Minho
Tipo: Conferência ou Objeto de Conferência
Publicado em /04/2011 ENG
Relevância na Pesquisa
48.045874%
The development of new products for i-textiles (interactive textiles) or e-textiles (electronic textiles) applications shows a significant growth in the most recent years due to their huge potential. Although much scientific work has been published in the last years, actual practical applications are still limited. This is due, on one hand, to unsatisfactory state of development of the technology and, on the other, to difficulties on the integration of technologies and methods of the textile and electronic areas. Products for e/i-textiles very often involve the use of sensors, preferably in the form of films, filaments or fibres, due to the inherent easy insertion in the product. For this purpose, electroactive filaments, that benefit from the piezoelectric properties of poly(vinylidene fluoride), PVDF, can be an interesting choice. There aresome works published in the literature related to the development of films with piezoelectric properties [1], that employ PVDF as the electroactive material. However, despite its importance, the manufacture methodologies employed are very difficult to use in industrial scale production. In this work a novel methodology for the production of electroactive filaments, by coextrusion of PVDF and an electrical conductive polymer composite...

Properties and processing by extrusion of electrically conductive multilayer filaments comprising polymer composites

Martins, R. S.; Gonçalves, Renato Ferreira; Azevedo, Tiago; Nóbrega, J. M.; Carvalho, Helder; Lanceros-Méndez, S.; Rocha, J. G.
Fonte: Sociedade Portuguesa de Materiais (SPM) Publicador: Sociedade Portuguesa de Materiais (SPM)
Tipo: Conferência ou Objeto de Conferência
Publicado em //2013 ENG
Relevância na Pesquisa
48.469478%
This work describes the production and characterization of three-layer piezoelectric filaments using two different electrically conductive polymers. The filaments were produced in a filament extrusion line, equipped with a coextrusion die that enabled a coaxial arrangement for a three-layer filament. For the inner and outer layers two different electrically conductive compounds were used, and the middle layer was made of the electroactive polymer PVDF. The produced filament can be used as a piezoelectric sensor, as described in other work [1]. A commercial conductive polymer grade of polypropylene compounded with carbon black and a commercial polypropylene containing 7 wt% of carbon nanotubes were studied and compared when employed as the filament conductive layers under various processing conditions, namely different process temperatures and drawing ratio. For evaluation purposes measurements of the electrical resistance of the inner and outer conductive layers were performed and correlated with the composition and processing conditions. The polypropylene based composite containing 7 wt% carbon nanotubes revealed to be the most effective material to be used in the production of three-layer piezoelectric filaments since it presents higher electrical conductivity and easier processing...

Study of poly(o-Ethoxyaniline) interactions with herbicides and evaluation of conductive polymer potential used in electrochemical sensors

Consolin Filho,Nelson; Leite,Fábio de Lima; Carvalho,Eduarda Regina; Venâncio,Everaldo Carlos; Vaz,Carlos Manoel P.; Mattoso,Luiz Henrique C.
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2007 EN
Relevância na Pesquisa
58.176313%
Interactions of four aromatic nitrogen-heterocyclic herbicides (atrazine, imazaquin, metribuzin and paraquat) with the conductive polymer poly(o-ethoxyaniline)-POEA, were studied with atomic force microscopy (AFM), UV-visible spectrophotometry (UV-Vis) and electrochemical impedance spectroscopy. AFM profiles of self-assembled (SA) films of POEA revealed that the polymer surface became rougher (on the nanoscale) when exposed to atrazine, imazaquin and metribuzin, but slightly smoother in contact with paraquat. This suggested that specific chemical interactions, possibly electroscopic, have occurred between nitrogen atoms in the polymer chain and the dissimilar groups in the various herbicide molecules, during adsorption of the latter onto the film. The UV-Vis analyses indicated a stronger interaction of POEA in solution with imazaquin, that has a special importance for the intended application. Sensors produced by coating microelectrodes with SA films of POEA were used to perform impedance spectroscopy in aqueous solutions of each herbicide. With the resulting data, it was possible to distinguish and set detection limits for each herbicide in water, corroborating AFM and UV-Vis results.

Electrochemical and Optical Investigation of Conductive Polymer and MWCNT Nanocomposite Film

Ehsani,Ali; Babaei,Ferydon; Mostaanzadeh,Hossein
Fonte: Sociedade Brasileira de Química Publicador: Sociedade Brasileira de Química
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/02/2015 EN
Relevância na Pesquisa
68.31162%
Composites of multi-walled carbon nanotubes (MWCNT) and conductive polymer with good uniformity were prepared by electropolymerization. Molecular modeling calculations were carried out for electroactive monomer (OAP) polymerization with density functional theory (DFT) level using 6-311G(d,p) basis set for all atoms and Gaussian 03 program package. The reflectance and transmittance amplitudes of the composite were obtained, using the continuity of the tangential components of electrical and magnetic fields at interfaces and solving the algebraic matrix equation. The calculated absorbance spectra as a function of wavelength for MWCNTs dispersed in the conductive polymer are depicted. Band gap of the p-type semiconducting film was obtained from the plot of (αhv)2 vs. photon energy.

Proton conductive membranes based on poly (styrene-co-allyl alcohol) semi-IPN

Loureiro,Felipe Augusto Moro; Marins,Evelyn Serrano de; Anjos,Gullit Diego Cardoso dos; Rocco,Ana Maria; Pereira,Robson Pacheco
Fonte: Associação Brasileira de Polímeros Publicador: Associação Brasileira de Polímeros
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/01/2014 EN
Relevância na Pesquisa
48.07508%
The optimization of fuel cell materials, particularly polymer membranes, for PEMFC has driven the development of methods and alternatives to achieve systems with more adequate properties to this application. The sulfonation of poly (styrene-co-allyl alcohol) (PSAA), using sulfonating agent:styrene ratios of 2:1, 1:1, 1:2, 1:4, 1:6, 1:8 and 1:10, was previously performed to obtain proton conductive polymer membranes. Most of those membranes exhibited solubility in water with increasing temperature and showed conductivity of approximately 10-5 S cm-1. In order to optimize the PSAA properties, especially decreasing its solubility, semi-IPN (SIPN) membranes are proposed in the present study. These membranes were obtained from the diglycidyl ether of bisphenol A (DGEBA), curing reactions in presence of DDS (4,4-diaminodiphenyl sulfone) and PSAA. Different DGEBA/PSAA weight ratios were employed, varying the PSAA concentration between 9 and 50% and keeping the mass ratio of DGEBA:DDS as 1:1. The samples were characterized by FTIR and by electrochemical impedance spectroscopy. Unperturbed bands of PSAA were observed in the FTIR spectra of membranes, suggesting that chemical integrity of the polymer is maintained during the synthesis. In particular...

Modification of Conductive Polymer for Polymeric Anodes of Flexible Organic Light-Emitting Diodes

Wang, Guang-Feng; Tao, Xiao-Ming; Xin, John H; Fei, Bin
Fonte: Springer Publicador: Springer
Tipo: Artigo de Revista Científica
Publicado em 17/03/2009 EN
Relevância na Pesquisa
48.045874%
A conductive polymer, poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate) (PEDOT:PSS), was modified with dimethyl sulfoxide (DMSO) in solution state, together with sub-sequential thermal treatment of its spin-coated film. The electrical conductivity increased by more than three orders of magnitude improvement was achieved. The mechanism for the conductivity improvement was studied at nanoscale by particle size analysis, field emission scanning electron microscopy (FESEM), and X-ray photoelectron spectroscopy (XPS). Smaller particle size was observed, resulting in larger contact area and better electrical conductive connections. Connection of conductive PEDOT increased on the surface of the PEDOT:PSS particles, which promoted high conductivity. Flexible anodes based on the modified PEDOT:PSS were fabricated. Flexible organic light-emitting diodes (FOLED) based the polymeric anodes have a comparable performance to those on indium–tin–oxide (ITO) anodes.

Protocol and cell responses in three-dimensional conductive collagen gel scaffolds with conductive polymer nanofibres for tissue regeneration

Sirivisoot, Sirinrath; Pareta, Rajesh; Harrison, Benjamin S.
Fonte: The Royal Society Publicador: The Royal Society
Tipo: Artigo de Revista Científica
Publicado em 06/02/2014 EN
Relevância na Pesquisa
48.514824%
It has been established that nerves and skeletal muscles respond and communicate via electrical signals. In regenerative medicine, there is current emphasis on using conductive nanomaterials to enhance electrical conduction through tissue-engineered scaffolds to increase cell differentiation and tissue regeneration. We investigated the role of chemically synthesized polyaniline (PANI) and poly(3,4-ethylenedioxythiophene) (PEDOT) conductive polymer nanofibres for conductive gels. To mimic a naturally derived extracellular matrix for cell growth, type I collagen gels were reconstituted with conductive polymer nanofibres and cells. Cell viability and proliferation of PC-12 cells and human skeletal muscle cells on these three-dimensional conductive collagen gels were evaluated in vitro. PANI and PEDOT nanofibres were found to be cytocompatible with both cell types and the best results (i.e. cell growth and gel electrical conductivity) were obtained with a low concentration (0.5 wt%) of PANI. After 7 days of culture in the conductive gels, the densities of both cell types were similar and comparable to collagen positive controls. Moreover, PC-12 cells were found to differentiate in the conductive hydrogels without the addition of nerve growth factor or electrical stimulation better than collagen control. Importantly...

Mesoscale Origin of the Enhanced Cycling-Stability of the Si-Conductive Polymer Anode for Li-ion Batteries

Gu, Meng; Xiao, Xing-Cheng; Liu, Gao; Thevuthasan, Suntharampillai; Baer, Donald R.; Zhang, Ji-Guang; Liu, Jun; Browning, Nigel D.; Wang, Chong-Min
Fonte: Nature Publishing Group Publicador: Nature Publishing Group
Tipo: Artigo de Revista Científica
Publicado em 14/01/2014 EN
Relevância na Pesquisa
48.47186%
Electrode used in lithium-ion battery is invariably a composite of multifunctional components. The performance of the electrode is controlled by the interactive function of all components at mesoscale. Fundamental understanding of mesoscale phenomenon sets the basis for innovative designing of new materials. Here we report the achievement and origin of a significant performance enhancement of electrode for lithium ion batteries based on Si nanoparticles wrapped with conductive polymer. This new material is in marked contrast with conventional material, which exhibit fast capacity fade. In-situ TEM unveils that the enhanced cycling stability of the conductive polymer-Si composite is associated with mesoscale concordant function of Si nanoparticles and the conductive polymer. Reversible accommodation of the volume changes of Si by the conductive polymer allows good electrical contact between all the particles during the cycling process. In contrast, the failure of the conventional Si-electrode is probed to be the inadequate electrical contact.

A compact, highly efficient and flexible polymer ultra-wideband antenna

Chen, S.J.; Kaufmann, T.; Shepherd, R.; Chivers, B.; Weng, B.; Vassallo, A.; Minett, A.; Fumeaux, C.
Fonte: IEEE Publicador: IEEE
Tipo: Artigo de Revista Científica
Publicado em //2015 EN
Relevância na Pesquisa
47.956436%
A compact, highly efficient and flexible ultra-wideband antenna operating from 3 to 20 GHz is proposed in this letter. The antenna is completely made from polymer comprising a patterned conductive polymer (PEDOT) thin film attached to a transparent sticky tape substrate. The overall dimension is less than a quarter-wavelength at the lowest frequency of operation and the device reaches a radiation efficiency of over 85% averaged throughout the frequency band. The antenna performs well under various bending conditions as demonstrated by measurements. The realized antenna offers great mechanical flexibility and robustness which indicates its promising potential for possible seamless integration in flexible electronics.; Shengjian Jammy Chen, Thomas Kaufmann, Roderick Shepherd, Benjamin Chivers, Bo Weng, Anthony Vassallo, Andrew Minett, and Christophe Fumeaux

Novel polypyrrole derivatives to enhance conductive polymer-tissue interactions; Novel PPy derivatives to enhance conductive polymer-tissue interactions

George, Paul M. (Paul Matthew)
Fonte: Massachusetts Institute of Technology Publicador: Massachusetts Institute of Technology
Tipo: Tese de Doutorado Formato: 142 p.
ENG
Relevância na Pesquisa
48.49649%
Developing materials that interact effectively with surrounding tissue is a major obstacle in sensor and drug delivery research. The body's natural immune response prevents foreign objects from easily integrating with an organism. Without an intimate link between a biomedical device and the proximate environment, reliable measurements or delivery of molecules is not possible. Many of the current materials used for biomedical applications are centered on inert substances and polymers that degrade in the body but have limited functional capabilities. This thesis work addresses the need to develop materials that are capable of interacting in biological environments. Polypyrrole (PPy) is a conducting polymer that is a promising biomaterial for drug delivery and sensing applications. Because PPy is a polymer that can be made in degradable forms and because it can be stimulated electrically, it is an interactive platform for biomedical applications. By accomplishing the following research objectives, this thesis work could help develop an effective polymeric paradigm for tissue interactions: 1) Develop a new method to effectively micro-pattern electrodeposited polymers and metals for in vivo devices 2) Determine the optimal synthesis conditions of the conductive polymer...

Investigating the Inter-Tube Conduction Mechanism in Polycarbonate Nanocomposites Prepared with Conductive Polymer-Coated Carbon Nanotubes

Ventura, Isaac Aguilar; Zhou, Jian; Lubineau, Gilles
Fonte: Springer US Publicador: Springer US
Tipo: Text
Publicado em 16/12/2015 EN
Relevância na Pesquisa
48.045874%
A well-known strategy to improve the electrical conductivity of polymers is to dope them with high-aspect-ratio and conductive nanoparticles such as carbon nanotubes (CNTs). However, these nanocomposites also exhibit undesirable properties such as damage-sensitive and history-dependent conductivity because their macroscopic electrical conductivity is largely determined by the tunneling effect at the tube/tube interface. To reduce these issues, new nanocomposites have been developed with CNTs that have been coated with a conductive layer of poly(3,4-ethylenedioxythiophene)poly(styrenesulfonate) (PEDOT/PSS). It has been posited that the insulating region between the CNTs is replaced by a conductive polymer bridge; this has not been proven up to now. We propose here to investigate in-depth how the macroscopic conductivity of these materials is changing when (1) varying the frequency of the electrical loading (impedance spectroscopy), (2) varying the mechanical hydrostatic pressure, and (3) varying the voltage of the electrical loading. The response is systematically compared to the one of conventional carbon nanotube/polycarbonate (CNT/PC) nanocomposites so we can clarify how efficiently the tunneling effect is suppressed from these composites. The objective is to elucidate further the mechanism for conduction in such material formulations.

Electrical characterization and electrogenic cell stimulation using a conductive polymer composite based on PEDOT:PSS/PVA/EG

Suárez-Vargas,José; Calderón,Marbely; Brämer-Escamilla,Werner; Briceño,Sarah; Sánchez,Iván; Bolaño,Pura; Caputo,Carlo
Fonte: Universidad Simón Bolívar; ; Publicador: Universidad Simón Bolívar; ;
Tipo: Artigo de Revista Científica Formato: text/html
Publicado em 01/06/2015 EN
Relevância na Pesquisa
58.07508%
Modern microelectrode arrays are being developed with emergent materials and approaches that provide properties superior to conventional metallic and inorganic semiconductor based electrodes. Newer materials include conducting polymers, nanotubes and graphene-based films. Here we propose a composite mixture with controlled electrical properties based on the p-type conductive polymer poly(3,4-ethylenedioxythiophene) doped with poly(styrenesulfonate) (PEDOT:PSS). To improve the biocompatibility and conductivity of the material, we added a combination of the polar organic compound ethylene glycol (EG), the surfactant sodium dodecyl sulfate (SDS) and polyvinyl alcohol (PVA). Using these mixtures, we fabricated films to interface electrical stimuli with rodent skeletal muscle fibers and ventricular cardiomyocytes. We demonstrated strong contractile responses and excellent biocompatible cell coupling with polymer-based films.