Electric Properties of Conducting Composite from Poly(ethylene oxide) and Poly(ethylene oxide)-Grafted Carbon Black in Solvent Vapor

A conducting composite from high molecular weight poly(ethylene oxide)(PEO) and low molecular weight PEO-grafted carbon black(CB) was prepared. The electric resistance of the composite in dry air and chloroform vapor was examined. The effects of many factors, such as CB content, CB type and its dispersion in composite, and thickness of the composite film, on the ratio of electric resistance of the composite in dry air (R0) and in chloroform vapor (R), defined as responsiveness (R/R0) of the conducting composite, were investigated. For both CB (Porousblack and Asahi 60H black) used in this study, at CB content of 20—50 wt%, the responsiveness is high over 104 time. In the case of low CB content, the responsiveness is lower than 0.1. To explain the responsiveness of the composite for high and low CB content, two conduction mechanisms were proposed. To clarify the relationship between responsiveness and amount of vapor absorption, a method to simultaneously determine the resistance and vapor absorption amount of the composite was developed.