Thermal Effects on Pull-Off Force in the Johnson–Kendall–Roberts Model

Abstract

In this study, we investigate the effects of thermal fluctuations on the generalized Johnson–Kendall–Roberts (JKR) model. We show that the distribution of pull-off forces in this model is similar to that of the Bradley model, and is also consistent with the experiment result observed in Wierez-Kien et al. (Nanotechnology 29(15):155704 2018). Increasing temperature leads to a broadening of the distribution, while leads to a reduction of the pull-off force. Additionally, the pull-off force, which is separated into an athermal term and a thermal-induced reduction term, is measured by using spring velocity ranging over 5 orders of magnitude. We show that for compliant spring, the pull-off force is significantly enhanced with increasing velocity, which is mainly attributed to the contribution of the thermal-induced reduction term, while the athermal term is barely sensitive to changes in velocity.