Multiple Cracking of Metallized Polyimide Kapton Films

Abstract

Mechanical behaviour of metallized polyimide Kapton films was studied. The adhesion of metallized films to Kapton films is approximately hundred-folds higher than that of coatings made by usual sputter deposition of a metal on a polymer substrate. Multiple cracking of a metallized film was observed. Cracks of two different scale levels are observed. The cracks of the first type (microcracks) are short with 1-2 µm length. The cracks of the second type are much longer and have length of several hundreds microns. The cracks of this type appear at higher strains as compared with the shorter ones. In thinner 7-µm-thick samples long cracks were not observed.