Understanding Physical Aging in Ultrathin Polymer Films via Molecular Simulations

Abstract

Physical aging in glassy polymer films has attracted much attention in the past two decades due to its strong correlation with the lifetime of polymer-based nano-devices. However, understanding the physical agingPhysical aging from the simulation point of view is still a big challenge due to the huge differences between the simulation and experimental time scales (microseconds vs. hours, days, and even years). Recently, we made a survey on the free volumeFree volume diffusion and annihilation (FVDA) model as employed in dynamic Monte Carlo simulationsMonte Carlo simulation to study the volume contraction of ultrathin polymer films. In this chapter, based on our recently developed simulation route, we discuss in what sense the simulation results could be applied to understand the physical aging in experiments. Some new insights, such as the slowing down of accelerated aging at extremely small thickness, and the existence of new confinement length scale in ultrathin polymer films based on the inversed free volume diffusion process, are also discussed.