Viscoelastic Analysis of Osmotic Blistering Behavior of Coating Film

The osmotic blistering behavior of polymeric coating film which is in contact with an aqueous environment has been investigated. In this study, the coating film has been assumed to be linearly viscoelastic. Interfacial stresses induced in a laminate model consisting of the viscoelastic film and the elastic substrate as the film absorbs moisture from the ambient environment have been investigated using the time-domain boundary element method. The overall stress intensity factor for interfacial cracks subjected to a uniform osmotic pressure has been computed using the tractions at the crack tip node. The magnitude of stress intensity factors decreases with time due to viscoelastic relaxation, but remains constant at large times.