The Dynamic Energy Band Model of Contact-Separation and Sliding Mode Triboelectric Charging of Polymers at the Metal-Polymer Interface.

Surfaces are central to human technology, with most historical achievements linked to their manipulation, yet insulating polymers often experience wear, abrasion, and electrostatic charging upon contact with other materials. Understanding the interplay between mechanical deformation and surface charge generation, triboelectrification, is essential for predicting and controlling polymer performance. This study investigates how plastic deformation by strain, a key determinant of polymer mechanical properties, influences triboelectric charge generation. Triboelectrification on stretched and unstretched polymers was measured using two complementary approaches: (i) probing electrical signals at the polymermetal interface during repeated contact separation cycles, and (ii) sliding a metal sphere along polymer surfaces while monitoring interface signals along a linear path. Results demonstrate that structural and physical changes in polymers, including crystallinity and tacticity induced by strain, strongly correlate with charge generation. We propose a dynamic energy band model in which mechanochemical changes at the interface create and decay energy states within the conduction and valence bands relative to the metal Fermi level. This framework accommodates multiple concurrent processes in triboelectric charging. Finally, surface charge density and electron mediated charge transfer can be predicted by evaluating the activation energies of all relevant processes. These findings advance the fundamental understanding of polymer triboelectrification under mechanical deformation and guide the design of materials and devices with controlled surface charging properties.