Temporal Decay Characteristics of Nanopatterned Tribocharge on Elastomer Surfaces*

Replica molding turned out to be a promising and facile technique for generating nanopatterned triboelectric charge on elastomer surfaces. As the tribocharges tend to disappear over time, it is imperative to investigate their longevity and temporal decay characteristics for sustained utilization. Monitoring the temporal decay of the nanopatterned tribocharge is a challenging task which necessitates extended and repeated charge measurements at the nanoscale resolution. In this work, we conducted such an experimental study on the tribocharge nanopatterned on PDMS surfaces using Kelvin probe force microscopy. Through extensive curve-fitting of the measurement results, we not only reaffirmed the inherent temporal decay of the tribocharges but also separated them into fast and slowly decaying components. Based on computer modeling of the replica molding process, we further attributed the fast and slowly decaying components to two different tribocharging mechanisms, i.e., tangential sliding and surface-normal separation between the material interface, respectively. These findings will enhance our understanding of tribocharging mechanisms on elastomer surfaces and benefit future exploration of nanoscale triboelectrification.