@article { ISI:000229298200025, title = {Role of non-linear processes in conducting polymer blends for piezo-sensors Part 2: studies on polyaniline/SBS blends}, journal = {Sensors and Actuators A-Physical}, volume = {120}, number = {2}, year = {2005}, month = {MAY}, pages = {474-481}, publisher = {ELSEVIER SCIENCE SA}, type = {Article}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

The electrical properties and piezo-response of conducting polymer blends have been investigated with respect to composition for styrene-butadiene-styrene (SBS) elastomer containing two grades of polyaniline (PANI). The blends were synthesized using solution/dispersion technique in which the conducting PANI was prepared with either HCl or dodecyl benzene sulfonic acid (DBSA) as dopant. Thick sheets cast from these exhibited high piezo-sensitive electrical resistance even at small mechanical load. The pressure dependence of resistance followed a non-linear power law of the type R = KP-m where K and m values changed considerably with composition. The current voltage characteristics in these blends were found to be highly non-linear and the conduction mechanism was either space charge limited or tunneling type depending on the concentration and nature of conducting additive. These various results have been explained on the basis of the phenomenological model developed incorporating the non-linear processes for electrical and mechanical properties. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {conducting polymer, non-linear process, piezo-sensors}, issn = {0924-4247}, doi = {10.1016/j.sna.2005.01.037}, author = {Radhakrishnan, S and Kar, Swarnendu B.} } @article { ISI:000241197300015, title = {Response characteristics of conducting polypyrrole bi-layer actuators: role of backing layer polymer}, journal = {Sensors and Actuators B-Chemical}, volume = {119}, number = {1}, year = {2006}, month = {NOV}, pages = {94-98}, publisher = {ELSEVIER SCIENCE SA}, type = {Article}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

The response of a bi-layer conducting polymer-based actuator has been studied with respect to various parameters such as backing layer thickness, backing layer modulus, applied voltage, etc. The bending angles for the bi-layer actuators made by depositing, conducting polypyrrole (PPy) films on backing layers using LDPE/LLDPE, SBS, Hytrel, PP, PET materials have been compared. The response of the bi-layer actuators indicates that there is optimum for the backing layer thickness as well as its material modulus together with the thickness of the conducting polymer at which the maximum bending is observed. Other geometrical parameters such as a length to width ratio also influence the response of these actuators and have to be chosen properly for the best actuator performance. (c) 2005 Elsevier B.V. All rights reserved.

}, keywords = {actuator, bi-layer, conducting polymer, polypyrrole, response}, issn = {0925-4005}, doi = {10.1016/j.snb.2005.11.061}, author = {Radhakrishnan, S. and Kar, Swarnendu B.} } @article { ISI:000245903300012, title = {Fabrication of MEMS composite-polymer gas sensor arrays for electronic nose}, journal = {Indian Journal of Pure \& Applied Physics}, volume = {45}, number = {4}, year = {2007}, note = {Indo-Chinese Workshop on Micro Electron Mechanical Systems (MEMS) and Related Technologies, Natl Phys Lab, New Delhi, INDIA, APR 05-07, 2006}, month = {APR}, pages = {321-325}, publisher = {NATL INST SCIENCE COMMUNICATION}, type = {Article, Proceeding Paper}, address = {DR K S KRISHNAN MARG, NEW DELHI 110 012, INDIA}, abstract = {

Sensor arrays capable of sensing different gases combined with a sampling system and a means of pattern classification and recognition comprise a basic system for an {\textquoteleft}Electronic Nose{\textquoteright} In the present work, a complete process for the fabrication of micro-cavities with sensing electrodes and volumes ranging from 2.5 to 12 nano-liters for the development of polymer gas sensors has been reported. An array of eight sensing cells in four sizes have been fabricated using SU-8 negative tone resist through UV-LIGA process developed at CEERI, Pilani. The length and width of the SU-8 cavities are: 250 x 250, 300 x 300, 500 x 500 and 500 x 600 micron and the depth of each of them was optimized to be 40 micron. These cavities filled with different polymer composites comprise the basic sensing cells for a variety of gases. The current paper presents the salient features of the fabrication process in detail and the results obtained in ethanol and methanol ambient using a polymer composite developed through dissolution of styrene and polyaniline in PMMA. A number of other composites such as Pc-Ppy, Pr-Ppy, Fc(+)-PPy have also been synthesized and tested for a high sensitivity in carbon monoxide.

}, keywords = {composite polymer, conducting polymer, electronic nose, polymer gas sensor, selectivity, sensitivity, sensor array}, issn = {0019-5596}, author = {Pant, B. D. and Kutnar, Mahesh and Lakshmi, Subha and Arora, Anil and Prasad, Mahanth and Sharma, Akshdeep and Patel, Mohan and Radhakrishnan, S. and Dwivedi, V. K.} } @article { ISI:000243650800011, title = {High-temperature, polymer-graphite hybrid composites for bipolar plates: effect of processing conditions on electrical properties}, journal = {Journal of Power Sources}, volume = {163}, number = {2}, year = {2007}, month = {JAN}, pages = {702-707}, publisher = {ELSEVIER SCIENCE BV}, type = {Article}, address = {PO BOX 211, 1000 AE AMSTERDAM, NETHERLANDS}, abstract = {

High-temperature thermoplastic-graphite composites are prepared using polyphenylene sulfide (PPS) and polyether sulfone (PES) containing natural graphite powder. All samples are prepared by high pressure compaction and heating to high temperatures. The effect of a third additional conducting component on the electrical resistance of these composites is studied. A low resistance of the order of 0.1 Omega can be obtained even for a graphite concentration of 50\% by addition of the third component. The effect of a mixing/blending technique on the anisotropy of conductivity is investigated. Solution blending of PES with graphite leads to lower anisotropy values than powder mixing and compression moulding. The samples when exposed continuously to a working temperature of 100 degrees C give a small but significant reduction in electrical resistance. X-ray diffraction studies on composites prepared by different techniques indicate that there is restructuring and crystallite re-orientation of the graphite phase in the samples. A large reduction in the crystallite size is observed for samples prepared by solution blending while re-orientation occurs after heat treatment. The changes in electrical properties can be correlated with these structural transformations in the composites. (c) 2006 Elsevier B.V. All rights reserved.

}, keywords = {bipolar plates, conducting polymer, fuel cell, graphite composites, hybrid materials, polyether sulfone, polypherylene sulfide}, issn = {0378-7753}, doi = {10.1016/j.jpowsour.2006.08.019}, author = {Radhakrishnan, S. and Ramanujam, B. T. S. and Adhikari, Arindam and Sivaram, S.} } @article { ISI:000251014600008, title = {Synthesis, characterization and actuation behavior of polyaniline-coated electroactive paper actuators}, journal = {Polymer International}, volume = {56}, number = {12}, year = {2007}, month = {DEC}, pages = {1530-1536}, publisher = {JOHN WILEY \& SONS LTD}, type = {Article}, address = {THE ATRIUM, SOUTHERN GATE, CHICHESTER PO19 8SQ, W SUSSEX, ENGLAND}, abstract = {

This investigation deals with the synthesis, characterization and actuation behavior of conductive polyaniline-coated electroactive paper actuators. The actuator is made by electrochemical deposition of conductive polyaniline on a cellulose paper. The aim of the investigation was to improve the bending displacement of electroactive paper actuators. The displacement outputs of the actuators show that a trilayer is better than a bilayer configuration. The nature of the dopant ion used in the electro-generation affects the performance. A change in humidity plays a vital role in actuation performance of the actuators. Comparing the performance of electroactive paper actuators with and without a conductive polyaniline coating, the coating improves the displacement output threefold. Finally, the actuation principle mechanism is addressed. (C) 2007 Society of Chemical Industry.

}, keywords = {bending actuator, conducting polymer, electroactive polymer (EAP), polyaniline}, issn = {0959-8103}, doi = {10.1002/pi.2297}, author = {Kim, Jaehwan and Yun, Sung-Ryul and Deshpande, S. D.} } @article { ISI:000262810900014, title = {Conducting polyaniline-nano-TiO2 composites for smart corrosion resistant coatings}, journal = {Electrochimica Acta}, volume = {54}, number = {4}, year = {2009}, month = {JAN}, pages = {1249-1254}, publisher = {PERGAMON-ELSEVIER SCIENCE LTD}, address = {THE BOULEVARD, LANGFORD LANE, KIDLINGTON, OXFORD OX5 1GB, ENGLAND}, abstract = {

Coatings prepared from polyaniline-nano-TiO2 particles synthesized by in situ polymerization were found to exhibit excellent corrosion resistance much superior to polyaniline (PANI) in aggressive environments. The corrosion Studies were carried out on steel plates coated with these formulations containing 10 wt\% polyaniline prepared with different concentrations of nano-TiO2. The electrochemical impedance spectroscopy was studied at periodic intervals during exposure to hot saline (65 degrees C) conditions for prolonged durations over a period of 90 h. The open circuit potential (OCP) was found to shift with time from -0.38 V SCE to more anodic side (-0.2 V SCE) much above that of bare steel (-0.5 VSCE). The presence of nano-TiO2 was found to be vital in the prevention of corrosion and the shift of OCP to anodic side. From these data, one could envisage more than 100 times improvement in the corrosion resistance especially for polyaniline prepared with 4.18 wt\% nano-TiO2. The exceptional improvement of performance of these coatings has been associated with the increase in barrier to diffusion, prevention of charge transport by the nanosize TiO2, redox properties of polyaniline as well as very large surface area available for the liberation of dopant due to nano-size additive. (C) 2008 Elsevier Ltd. All rights reserved.

}, keywords = {Anticorrosion, Coating, conducting polymer, Nano-composite, Titanium dioxide}, issn = {0013-4686}, doi = {10.1016/j.electacta.2008.08.069}, author = {Radhakrishnan, S. and Siju, C. R. and Mahanta, Debajyoti and Patil, Satish and Madras, Giridhar} } @article { ISI:000265814500012, title = {Polypyrrole functionalized with ferrocenyl derivative as a rapid carbon monoxide sensor}, journal = {Synthetic Metals}, volume = {159}, number = {5-6}, year = {2009}, month = {MAR}, pages = {415-418}, publisher = {ELSEVIER SCIENCE SA}, address = {PO BOX 564, 1001 LAUSANNE, SWITZERLAND}, abstract = {

A rapid carbon monoxide detection system was developed with the electrochemical functioncalization of polypyrrole (PPy) with ferrocenylmethyltrimethylammonium iodide (FTMA-I) as a co-dopant exhibits very high sensitivity to ppm levels of carbon monoxide gas and fast recovery under normal dry room temperature conditions. The co-dopant was synthesized mainly to incorporate into PPy electrochemically to modify the properties in order to sense carbon monoxide (CO) gas. The FTMA-I doped PPy exhibited the characteristics oxidation/reduction peaks for ferrocene in its cyclic voltammograms. The modified PPy films deposited on interdigited electrodes gave rapid sensitivity within a second to 300 ppm carbon monoxide gas and good sensitivity factor was observed even at 4 mmol of the functional groups in the polymer for 300 ppm carbon monoxide gas. This material detected the CO gas concentration as low as 100 ppm. (C) 2008 Elsevier B.V. All rights reserved.

}, keywords = {carbon monoxide, Chemical sensor, conducting polymer, polypyrrole}, issn = {0379-6779}, doi = {10.1016/j.synthmet.2008.10.013}, author = {Paul, Santhosh and Chavan, Nayaku and Radhakrishnan, S.} } @article { ISI:000287058200011, title = {Dopant induced effect on electrocatalytic reduction of nitrobenzene using conducting polypyrrole thin film electrodes}, journal = {Journal of Applied Polymer Science}, volume = {120}, number = {2}, year = {2011}, month = {APR}, pages = {719-724}, publisher = {WILEY-BLACKWELL}, address = {COMMERCE PLACE, 350 MAIN ST, MALDEN 02148, MA USA}, abstract = {

Conducting polypyrrole electrodes were prepared by electrochemical polymerization of pyrrole on vacuum-metallized glass substrates. These electrodes were modified by doping with a range of metal halides as dopant ions having different electronegativity. Electrochemical reduction of nitrobenzene using these electrodes was studied by means of cyclic voltammetry technique in acetonitrile medium containing aqueous HClO(4) (0.1M) as supporting electrolyte. It was found that the electronegativity of the dopant ion played a very important role in the electrocatalytic activity. Polypyrrole doped with nickel chloride gave the highest anodic current at the reduction potential of nitrobenzene. The results were explained on the basis of charge transfer efficiency at the electrode-electrolyte interface, which was associated with the acceptor state created by the dopant in the semi-conducting polymer. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 120: 719-724, 2011

}, keywords = {charge transfer, conducting polymer, Doping, electrocatalysis, nitrobenzene, polypyrrole, reduction}, issn = {0021-8995}, doi = {10.1002/app.31417}, author = {Adhikari, Arindam and Radhakrishnan, S.} } @article {46883, title = {Flexible energy storage device based on poly(N-phenylglycine), an incentive-energy pseudocapacitive conducting polymer, and electrochemically exfoliated graphite sheets}, journal = {ACS Sustainable Chemistry \& Engineering}, volume = {8}, year = {2020}, month = {APR}, pages = {6433-6441}, type = {Article}, abstract = {

Poly(N-phenylglycine) (PNPG), an original pseudocapacitive conjugative conducting polymer (CP), was synthesized by the electro-oxidative polymerization method. The synthesis process involves in situ polymerization and electro-deposition of N-phenylglycine onto the surface of highly conductive, few-layered, exfoliated flexible graphite sheets (EFGSs). At first, the promising features of the conjugative structure of the as-prepared protonated PNPG were thoroughly investigated by UV-vis absorption spectrophotometry, micro-Raman spectroscopy, and X-ray photoelectron spectroscopy analysis. The protonated nitrogen groups facilitate the rapid accessibility of counter ions from the electrolyte. Electrochemical studies revealed that the PNPG/E-FGS electrode exhibits an extraordinary areal specific capacitance of 367 mF cm(-2) at 10 mV s(-1). A flexible solid-state symmetrical supercapacitor was further fabricated using PNPG/E-FGS electrodes, exhibiting a specific capacitance as high as 199 mF cm(-2) at 1 mA cm(-2) with an operating voltage of 1.1 V. Furthermore, the device delivered an excellent specific energy of 8.36 mu W h cm(-2) at a power density of 1.65 mW cm(-2) in a working potential window of 1.1 V. More significantly, the energy density was nearly doubled to 16.1 mu W h cm(-2) upon extending the potential window from 1.1 to 1.5 V. The extremely redox-active CP electrode is highly suitable for applications in high-energy electrochemical capacitors with wide operating potential window.

}, keywords = {conducting polymer, electro-polymerization, exfoliated graphite, flexible supercapacitor, poly(N-phenylglycine)}, issn = {2168-0485}, doi = {10.1021/acssuschemeng.0c00880}, author = {Muniraj, Vedi Kuyil Azhagan and Boukherroub, Rabah and Shelke, Manjusha Vilas} }