Probing static discharge of polymer surfaces with nanoscale resolution

TL;DR

This paper introduces a nanoscale method to measure static charges on polymer surfaces, revealing charge dynamics, discharge phenomena, and material properties relevant for triboelectric applications.

Contribution

The study develops a rapid, in-situ nanoscale technique for quantifying triboelectric charges, enabling detailed analysis of charge behavior on dielectric surfaces.

Findings

Differentiated strongly and weakly charging polymer compositions.

Revealed electrostatic discharge phenomena upon contact.

Estimated maximum charge density of 5x10^-5 C/m^2.

Abstract

Triboelectric charging strongly affects the operation cycle and handling of materials and can be used to harvest mechanical energy through triboelectric nanogenerator set-up. Despite ubiquity of triboelectric effects, a lot of mechanisms surrounding the relevant phenomena remain to be understood. Continued progress will rely on the development of rapid and reliable methods to probe accumulation and dynamics of static charges. Here, we demonstrate in-situ quantification of tribological charging with nanoscale resolution, that is applicable to a wide range of dielectric systems. We apply this method to differentiate between strongly and weakly charging compositions of industrial grade polymers. The method highlights the complex phenomena of electrostatic discharge upon contact formation to pre-charged surfaces, and directly reveals the mobility of electrostatic charge on the surface. Systematic characterization of commercial polyethylene terephthalate samples revealed the compositions with the best antistatic properties and provided an estimate of characteristic charge density up to 5x10-5 C/m2. Large-scale molecular dynamics simulations were used to resolve atomistic level structural and dynamical details revealing enrichment of oxygen containing groups near the air-interface where electrostatic charges are likely to accumulate.