Test speed dependency of peel strength of ACF joints

Model ACF joints between glass and flexible substrates were fabricated under various bonding conditions in order to achieve various curing states of adhesive binder. The 90° peel strength of the joints was evaluated under various test speed conditions. During the peel tests, an anchoring effect that is effective to increase the peel strength can be induced by an interdigitated Cu electrode pattern on the flexible substrates. In addition, the mechanical behaviors of the adhesive binder are influential to the peel strength of the joints. The peel strength of the joints tends to decrease with decreasing the test speed due to stress relaxation by the adhesive binder. By using the test speed dependency, the effect of visco-elastic deformation behavior on the peel strength can be characterized separately from the interfacial factors. The evolution behavior of polymer structure in the adhesive binder during the bonding process is also deduced based on the test speed dependency of peel strength.