Flexible Encapsulation Process-Property Relationships for Flexible Hybrid Electronics

FHE platforms need flexible encapsulation for protection from use stresses of flexing, folding, flex-to-install while allowing for integration with the intended packaging architectures. Traditional encapsulation materials and packaging architectures are geared towards rigid structures. Encapsulants may have a number of components including binders, catalysts, curing agents, accelerators, fillers, modifiers, and additives. Manufacturing process-expected performance relationships of flexible encapsulation materials are not well understood. In this study, process-property relationships have been studied for a number of different flexible encapsulant formulations under a number of cure profiles, cure durations, surface preparation and substrate materials. The effect of additive printing on the interfacial robustness has been studied for liquid encapsulation of flexible hybrid electronics. The interfacial strength has been assessed using the 90° peel test. Studied parameters included peak-peel strength, steady-state peel strength, and ratio of the peak-peel strength to the steady-state peel strength. In addition to the mean values the variance in the values has also been quantified. The process-property relationships can be used for material selection.