Giant mobility of surface- trapped ionic charges following liquid tribocharging

• 成果类型: Article
• 署名作者: Benrahla, Zouhir; Saide, Tristan; Burnaz, Louis; Verneuil, Emilie; Gravelle, Simon; Comtet, Jean
• 署名单位: Centre National de la Recherche Scientifique (CNRS); Universite PSL; Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI); Sorbonne Universite; Centre National de la Recherche Scientifique (CNRS); Communaute Universite Grenoble Alpes; Universite Grenoble Alpes (UGA)
• 刊物名称: PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
• ISSN/ISSBN: 0027-9595
• DOI: 10.1073/pnas.2505841122
• 发表日期: 2025-09-16
• 关键词: contact electrification; interfaces; electricity; diffusion; droplets; moisture

摘要

The sliding motion of aqueous droplets on hydrophobic surfaces leads to charge separation at the trailing edge, with implications from triple- line friction to hydrovoltaic energy generation. Charges deposited on the solid surface have been attributed to ions or electrons ripped off from the liquid drop. However, the dynamics and exact physicochemical nature of these surface- trapped charges remains poorly explored. Here, we take advantage of a scanning- based electrostatic mapping technique, to directly quantify the spatiotemporal dynamics of surface deposited charges in the wake of droplets sliding on hydrophobic surfaces. We confirm the ionic nature of these interfacially trapped charges, and evidence that they undergo very fast bidimensional diffusive transport, gliding with low friction at the solid/gas interface. We interpret our observations in the framework of molecular dynamics simulation of hydrated ions adsorbed on solid surfaces, revealing a peculiar transport mechanism limited by purely interfacial friction of the ionic solvation shell with the solid surface. By uncovering the unexpected dynamics of these ionic puddles-a distinct state of interfacial ionic matter-our findings have general implications for molecular- scale ionic transport, electrified matter, and wetting dynamics at interfaces.