Study of the interfacial adhesion properties of a novel Self-healable siloxane polymer material via molecular dynamics simulation

Abstract

The reported outstanding adhesive and self-healing properties of a novel siloxane polymer – DOSS, have made it a promising candidate as polymer matrix of thermal interface materials (TIM). To explore its potential use in TIM, here we conduct systematic investigations on the interfacial properties of the DOSS/NiO interfaces at microscopic-scale using molecular dynamics (MD) simulations. MD can provide atomic-scale information which can hardly be obtained using experimental techniques. NiO presents at the surface of the plating layer of copper heat spreader in electronic packaging. DOSS is found to form rich hydrogen bonds with NiO, resulting in stronger adhesion to NiO compared to polydimethylsiloxane (PDMS), a conventional TIM matrix. The greater strength and ductility of DOSS compared to PDMS is ascribed to its rich hydrogen bonds and star-like topology. The strength changes with tensile rate, and is attributed to different strength and relaxation time of the bonded and non-bonded interactions. For ductility, an optimal temperature is found at 375 K. The DOSS has good self-healing ability, which is characterized by an 85% recovery of hydrogen bonds at 450 K. The microscopic insights provided by current work may shed lights on the design of DOSS as future potential polymer matrix to be used in TIM.