Adhesive strength Island blister test

Recently, there have been reported several developments of the common blister test method." These include the island-blister test and the inverted-blister test developed by Fernando and Kinloch. Both of these test methods are designed to enable the adhesive fracture energy to be measured for a coating of thin adhered film where the coating or film has insufficient strength to resist the pressure needed for debonding if the standard blister test was employed. Wan and Mai have described a blister test in which the crack is driven by the expansion of a fixed mass of gas and stable growth ensues. ... 

According to the final use, there exist different methods to measure the adhesive strength of polymeric materials. The island blister test and 90° peel test are particularly suited to determine the level of adhesion of very thin films in electronic applications. In the case of structural adhesives, the lap shear strength of three- or multiple-layer structures is a typical standard. 

As stated earlier, adhesion is a major concern in electronic applications involving thin polyimide films either coated on hard substrates or laminated with metal ribbons. In these cases, neither lap-shear nor die-shear techniques allow the determination of the adhesion strength this can be done by using either the 90° peel test or the island blister test whose principles are sketched in Figs 12.26 and 12.27. The 90° peel test provides reliable data for the measurement of practical adhesion, especially useful for comparing the effect of surface treatments on the interfacial adhesion. The standard peel test procedure has been modified to determine the adhesive strength of thin polyimide films coated onto 10-cm silicon wafers. The equipment illustrated in Fig. 12.26 maintains a 90° peel effort during the test conducted at room temperature with a constant rate of crosshead displacement of 2 mm min . ... 

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