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

Zernike Institute for Advanced Materials, University of Groningen - Nijenborgh 4, 9747 AG Groningen, The Netherlands, EU

^a m.i.bulacu-cioceanu@rug.nl

Received: 6 December 2010
Accepted: 14 February 2011

Abstract

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 G₀ 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.