Self-organization of current channels percolation in polymer composite films with thermal nonlinearity of conductivity: comparison of experimental data and computer simulations

Abstract

Numerical methods are developed to solve the problem of abnormal changes of current (conductivity) in polymer composite films which may be used as current, pressure or temperature sensors. General nonlinear model includes the heat equation, the nonlinear dependence of the resistivity of insulating composite intervals on temperature, taking into account the dehydrochlorination reaction, the appearance of conducting systems conjugated double bonds, and Ohm's law for full control circuit net. The property of thermal conductivity equation to smooth surges of source function allows to resolve the nonlinear closed system and carry out calculations by successive small time steps. As a result of numerical calculations we succeeded to explain and simulate virtually all previously seemed anomalous phenomena including spontaneous transitions in the highly conductive state, the conductivity jumps with temperature change, the dependence on sample thickness, etc.