Novel dye+solid polymer electrolyte material for optical humidity sensing
TL;DR: In this paper, the experimental observations show that certain dyes when incorporated in solid polymer electrolytes (SPE) can serve as an excellent candidates for optical humidity sensing Crystal violet (CV) have been incorporated in poly(vinyl alcohol) (PVA)/H3PO4, which is known to be a SPE and a good proton conductor Films of PVA/H 3PO4 containing CV dye have been studied for use in optical humidity detection.
About: This article is published in Organic Electronics.The article was published on 2001-09-01. It has received 40 citations till now. The article focuses on the topics: Proton conductor & Vinyl alcohol.
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TL;DR: In this paper, a reduction of the silver salt in aqueous aniline leads to the formation of silver nanoparticles which in turn catalyze oxidation of anilines to polyaniline.
216 citations
TL;DR: The numerous examples of portable instrumentation presented have been classified according to direct-recognition and reagent-based sensing, and within these, by absorption and emission-based systems, and the conclusion discusses some key trends and future perspectives.
126 citations
TL;DR: In this paper, the spectral properties of chemically synthesized polyanilines are analyzed and thermal properties of these polymers are found to be affected by varying the protonation media (acetic, citric, oxalic, and tartaric acid).
Abstract: Spectroscopic [UV–visible and Fourier transform IR (FTIR)] and thermal properties of chemically synthesized polyanilines are found to be affected by varying the protonation media (acetic, citric, oxalic, and tartaric acid). The optical spectra show the presence of a greater fraction of fully oxidized insulating pernigraniline phase in polyaniline doped with acetic acid. In contrast, the selectivity in the formation of the conducting phase is higher in oxalic acid as a protonic acid media. The FTIR spectra of these polymers reveal a higher ratio of the relative intensities of the quinoid to benzenoid ring modes in acetic acid doped polyaniline. Scanning electron micrographs revealed a sponge-like structure derived from the aggregation of the small granules in acetic acid and oxalic acid doped polyaniline. A three-step decomposition pattern is observed in all the polymers, regardless of the protonic acid used for the doping. The second step loss related to the loss of dopant is found to be higher in the oxalic acid doped polymer. In accordance with these results the conductivity is also found to be higher in oxalic acid doped material. The temperature dependent conductivity measurements show the thermal activated behavior in all the polymers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 2043–2049, 2004
120 citations
TL;DR: In this paper, polyaniline and poly( o -toluidine) doped with p-toluene sulphonic acid (p -TSA) were synthesized by in situ chemical polymerization method using ammonium per sulphate as an oxidizing agent.
113 citations
TL;DR: In this paper, a conducting polymer, polyaniline, was synthesized by chemical polymerization using different inorganic acids, such as HCl, H2SO4, HClO 4, HNO3, and H3PO4, as protonic acid media.
Abstract: A conducting polymer, polyaniline, was synthesized by chemical polymerization using different inorganic acids, such as HCl, H2SO4, HClO4, HNO3, and H3PO4, as protonic acid media. The synthesized polymers were characterized using UV-visible and FT-IR spectroscopy. A granular type of morphology was observed under SEM for HCl, HNO3, and H3PO4 doped polyanilines. However, HClO4 doped polyaniline shows the folded lamellar structure derived from the fibers. The thermal stability of these polymers was investigated with the help of thermogravimetric (TG/SDTA) analysis. The formation of a greater fraction of the conducting emeraldine salt phase is observed in HClO4 as a protonic acid media. The thermal stability of H3PO4 doped material is found to be better as compared with other acids. An increase in conductivity with an increase in temperature was observed in all the samples except for HClO4 doped polyaniline. Polym. Eng. Sci. 44:1676–1681, 2004. © 2004 Society of Plastics Engineers.
99 citations
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TL;DR: In this paper, the response to relative humidity of SiO2 composite films was analyzed with their complex impedance spectra at different humidities and the stability of the response against different aging environments was examined.
Abstract: Nafion, sol-gel derived SiO2 and SiO2/Nafion composite films were prepared through casting and dip-coating methods. Impedance response of the films to relative humidity and the stability of the response against different aging environments were examined. The response to relative humidity of each film was analyzed with their complex impedance spectra at different humidities.
180 citations
TL;DR: The spectrum of cobalt chloride on the fiber is similar to a transmission spectrum rather than an attenuated totla reflection (a.t.r.) spectrum because of the refractive index of the film which is slightly greater than that of the fiber.
125 citations
TL;DR: In this paper, the authors describe the fabrication and characterisation of a thick-film humidity sensor based on the semiconducting metal oxide MnWO 4, which possesses a novel "sandwich"-configuration with a 40 μm porous MnwO 4 ceramic layer sandwiched by two 10 μm polarity-reversed, interdigitated metal films.
Abstract: The paper describes the results of studies on the fabrication and characterisation of a thick-film humidity sensor based on the semiconducting metal oxide MnWO 4 . The sensor element possesses a novel ‘sandwich’-configuration with a 40 μm porous MnWO 4 ceramic layer sandwiched by two 10 μm polarity-reversed, interdigitated metal films. Instead of traditional glass frits, LiCl powders are used as adhesion promoters for sintering the sensor paste. With this method, MnWO 4 powders with an average particle size of 3.0 μm are sintered at the standard thick-film firing temperature of 850°C. The sintered ceramic layer exhibits a porous structure. The novel electrode arrangement combines the advantages of humidity sensors in the form of a parallel capacitor with those in the form of an interdigital capacitor, permitting a high sensitivity and a fast response. The influence of temperature on the sensor characteristics has been compensated for by integrating a thick-film NTC resistor. The humidity sensor shows no cross-sensitivity to organic vapour. The organic contamination on the sensor surface can be burned out by heating the sensor element at about 400°C with the refresh heater printed on the back side of the substrate.
117 citations
TL;DR: In this paper, the electrochromic response of conducting polypyrrole (PPy)/Prussian blue (PB) and conducting polyaniline (Pani)/Pussian blue composite films has been studied in different electrolytes such as KCl, LiClO 4, K 2 SO 4, KNO 3, KI/I 2, etc., by depositing the PB films on top of the conducting PPy and PANI films.
111 citations
99 citations