Surface chemical etching behaviour of kapton-H polyimide: Polarization effects

Polarization induced surface chemical etching behaviour of kapton-H polyimi de has been studied using NaOCl as etchant at 55 degrees C. The poling has been done at 80, 120 and 150 degrees C using ade field of 1000V following t he usual method. The etching behaviour has also been investigated fbr the s amples given similar heat-treatment but without applying any field. It is o bserved that the bulk etch rate increases in heat-treated samples, The indu ced polarization results in a decrease in the etch rate. The imide and the carbonyl groups both appear to be responsible for etching process. Loss of absorbed water due to heat treatment and increase in inter molecular forces due to polarization mainly governs the etching behaviour of polarized kapt on-H.