Evaluation of the Constrained Blister Test for Measuring Adhesion

The constrained blister test (CBT) was evaluated as a method for measuring adhesion using a model system, electrical tape bonded to polystyrene. Pressure is applied through a circular inlet hole in the substrate, causing the adhesive to “blister” up and peel radially away from the substrate. A glass constraint, placed some distance above the adhesive, limits deformation of the adhesive in the vertical direction and promotes radial peel. By operating at low spacer height (the distance of the constraint above the adhesive) and very low growth rates, the energy spent for deformation of the adhesive and viscoelastic dissipation is minimized. Blister radial growth was linear with time, and growth rate increased linearly with the second power of the energy input. An intrinsic, rate-independent adhesion energy was obtained by extrapolation to zero crack growth rate. The CBT was compared with two peel tests. The dependence of the growth rate on energy input was different, but the extrapolation to zero growth rate gave the same value of the intrinsic adhesion energy.