Experimental Study of Interfacial Fracture Toughness in a SiNx/PMMA Barrier Film

Organic/inorganic multilayer barrier films play an important role in the semihermetic packaging of organic electronic devices. With the rise in use of flexible organic electronics, there exists the potential for mechanical failure due to the loss of adhesion/cohesion when exposed to harsh environmental operating conditions. Although barrier performance has been the predominant metric for evaluating these encapsulation films, interfacial adhesion between the organic/inorganic barrier films and factors that influence their mechanical strength and reliability has received little attention. In this work, we present the interfacial fracture toughness of a model organic/inorganic multilayer barrier (SiNx–PMMA). Data from four point bending (FPB) tests showed that adhesive failure occurred between the SiNx and PMMA, and that the adhesion increased from 4.8 to 10 J/m2 by using a variety of chemical treatments to vary the surface energy at the interface. Moreover, the adhesion strength increased to 28 J/m2 by crea...