Department of Theoretical and Applied Mechanics (UIUC)
Abstract
We study theoretically the forced separation of two adhesive surfaces linked via a large number of parallel non-convalent bonds. We use a Brownian dynamic simulation to describe the kinetics and compute the force???distance curve and the rupture force for separating adhesive surfaces with a constant rate. We also implement a statistical mechanics framework to describe the pulling process, using a two-step reaction model and reaction rates obtained from the first passage time description for diffusive barrier crossing in a pulleddistance-dependent potential. A single integral mean first passage time (IMFPT) expression and the Kramers time are used to calculate the rate coefficients. The dependence of the rupture force on the pulling rate exhibits three regimes. In the near-equilibrium regime, the rupture force asymptotically approaches the equilibrium rupture force, which determined by the intrinsic free energy difference. In the non-equilibrium regime, the rupture force increases with the pulling rate and correlates with the rupture bond energy and the intrinsic off-rate. In the far from the equilibrium regime where the rebinding is relevent, the rupture force is determined by the rupture bond energy.published or submitted for publicationis not peer reviewe
