Effects of pulling velocity and temperature revealed in polymer pull-out simulations

We present a molecular dynamics study of pulling-out polymer chains from ensembles of entangled polymers, with possible applications in single-molecule pulling techniques. The effects of pulling velocity and temperature are identified separately in the adhesive strength G and in the debonding time t(D) required to completely pull-out the chains from the interface between two polymeric bulks. G is found to have a quasi-static threshold value G(0) beyond which it increases linearly with the velocity, while an apparent glass transition temperature is identified in its dependence on temperature. t(D) has a power law decay with pulling velocity and decreases linearly with temperature. The combination of these independent effects has two remarkable consequences: time-temperature superposition is valid for pull-out experiments, and a master curve exists for the time evolution of the work of adhesion at various temperatures and velocities, by proper normalization. Copyright (C) EPLA, 2011