Adhesion Strength of Polymer Coatings studied by Laser Induced Delamination

Abstract

ABSTRACTLaser Induced Delamination is a novel technique aimed at quantification of adhesion of thin polymer films to a metal substrate. In this technique a high power IR pulsed laser beam (maximum 500 mJ in 5 ns) is used to create the primary delaminated area in the form of a blister. The blister is formed due to heating of the metal substrate and because of partial evaporation of the polymer material adjacent to the interface. By varying the power of the laser pulse the gas pressure inside the blister is increased until further delamination takes place. This critical pressure is related to the strength of adhesion of the polymer to the substrate. The shape of the blister (radius and height) is controlled with a stylus profiler and with an optical confocal microscope.In the present work 30 μm thick PET films on steel substrate were studied. From the shape of the obtained blisters the strength of adhesion of the polymer is estimated. Various models describing blister formation and growth are discussed.