Correlation between stick-slip frictional sliding and charge transfer

TL;DR

This paper presents a stick-slip model that explains the correlation between frictional sliding and charge transfer, challenging the idea that contact charging is the primary cause of friction.

Contribution

The proposed model captures the observed correlation between stick-slip events and charge transfer without relying on contact charging as the main friction mechanism.

Findings

The model reproduces the correlation between force jumps and charge transfer.

Friction scale factors are independent of normal load.

Stick-slip dynamics are governed mainly by visco-elastic and plastic deformation timescales.

Abstract

A decade ago, Budakian and Putterman (Phys. Rev. Lett., {\bf 85}, 1000 (2000)) ascribed friction to the formation of bonds arising from contact charging when a gold tip of a surface force apparatus was dragged on polymethylmethacrylate surface. We propose a stick-slip model that captures the observed correlation between stick-slip events and charge transfer, and the lack of dependence of the scale factor connecting the force jumps and charge transfer on normal load. Here, stick-slip dynamics arises as a competition between the visco-elastic and plastic deformation time scales and that due to the pull speed with contact charging playing a minor role. Our model provides an alternate basis for explaining most experimental results without ascribing friction to contact charging.