A CONDUCTIVE AND HUMIDITY-SENSITIVE COMPOSITE FILM DERIVED FROM POLY(O-PHENYLENEDIAMINE) AND POLYVINYL-ALCOHOL

Electrically conducting composite films have been prepared from the po lymer solution of conducting poly o-phenylenediamine (PoPD) and noncon ducting polyvinyl alcohol (PVA). This composite film showed a very low Value of the percolation threshold (0.1 Volume percent of the PoPD co ntent) where the conductivity rose sharply. On the other hand, the con ductivity of the prepared composite film was linearly related to the a tmospheric humidity, extending from 2.5 x 10(-5) to 3.5 X 10(-1) S . C m-1. The humidity-dependence of the conductivity was caused by the cha nge in the acid-base equilibrium between the PoPD and PVA in the compo site film.