Conducting polymer-based tests

From the cost point of view, precious metals (such as Au and Pt) are surely out of contention for practical coatings on SS substrates, although they might be used for short laboratory tests. In fact, electrochemical corrosion cells will be generated from the possible pinholes in the coatings due to the electrochemical dissimilarity of the precious metals and SSs in a PEMFC environment. Difficulties encountered with the carbon-based and conductive polymer-based coatings are application at intermediate temperatures, the cold-start issue, and the differences in thermal expansion coefficients between the coating itself and the substrate SS. The risk of... 

Among those several different types of transducers based on CNTs, the CNT-composite electrode, which was the first CNT electrode tested in 1996, is still widely used with different composite materials such as conducting polymers, nanoparticles, sol-gel, etc. The usefulness of these electrodes is based on their high sensitivity, quick response, good reproducibility, and particularly long-term stability. We expect to see continued research activities using CNT-composite electrodes. 

The first successful static firing of plastisol propellant took place late in 1950 as part of a broad program conducted by Atlantic Research Corp. to investigate and evaluate plastisol propellants and methods for their manufacture (16). Major attention was directed to poly (vinyl chloride), cellulose acetate, and nitrocellulose, although other polymers were tested for their suitability (17). Patent applications were filed for plastisol propellant compositions and manufacturing processes, based on poly(vinyl chloride) (PVC) (19) and on nitrocellulose (18). The commercial availability of dispersion grade PVC enabled work with this resin to advance rapidly. The balance of this paper is devoted to a discussion of PVC plastisol propellants and their manufacture. 

Preliminary conductivity measurements indicate that the polymers based on the anionic system are ionically conductive, whereas the nonionic based polymers are non-conductive. AC impedance tests were done on a thick film ( limn thick) using sodium sulfate as the electrolyte in a specially designed closed cell. The resistivity of polystyrene obtained from middle phase microemulsions was found to be in the rjange of lOMO ohm-cm, compared to lO o -10 2 ohm-cm for bulk polystyrene. A thin film of the polymer was also obtained on graphite electrodes by UV irradiation. Electrochemicd measurements using such polymer coated electrodes also suggest that the film is conductive. SEM micrographs before and after the electrochemical measurements indicate that the polymeric film is stable and porous. 

To test this novel architecture as a tool for classification, a simulated experiment was performed. The case of chemo-resistive sensors was considered because of the simple involved electronics. This class of sensors is rather wide and can include sensors based either on inorganic (e.g. metal-oxide semiconductors) or organic (e.g. conducting polymers) sensitive materials. The concepts here illustrated can be extended, with a proper modification of the AORN architecture, to different kinds of chemical sensors. Actually, the features of the olfactive epithelium define the following structure of the AORN. 

Voltammetric sensors based on chemically modified electrodes (conducting polymers, phthalocyanine complexes) with improved cross-selectivity were developed for the discrimination of bitter solutions [50], The performance and capability were tested by using model solutions of bitterness such as magnesium chloride, quinine, and four phenolic compounds responsible for bitterness in olive oils. The sensors gave electrochemical responses when exposed to the solutions. A multichannel taste sensor was constructed using the sensors with the best stabilities and cross-selectivities and PCA of the signals allowed distinct discrimination of the solutions. 

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