Gas permeation and temperature effects in laser-induced delamination

Laser-induced delamination (LID) is a technique aimed at measuring the work of adhesion of thin polymer coatings on metal substrates. A laser pulse is used to create a blister that initiates delamination of the film under pressure. The stress fields in the blister wall and the work of adhesion of the interface are determined using a linear elastic model.In this paper we discuss validity of the LID results addressing permeation of gas through the blister wall and the initial high temperature of the substrate. A procedure to account for the effect of gas permeation in the calculations of the work of adhesion is proposed. Permeation of gas is also considered under compressive and tensile in-plane stresses. Modeling of the permeation process demonstrates a good agreement with the experiment.At early stage of the blister formation the metal substrate and the blister gas experience high temperatures. The time scales of the cooling processes are estimated. Possible effects of the high temperatures on the permeation of gas and on the process of delamination are discussed.