Single-collision statistics reveal a global mechanism driven by sample history for contact electrification in granular media

Abstract

Models for same-material contact electrification in granular media often rely on a local charge-driving parameter whose spatial variations lead to a stochastic origin for charge exchange. Measuring the charge transfer from individual granular spheres after contacts with substrates of the same material, we find that the charge-driving parameter is global, not local. Cleaning and baking samples fully resets their charging behavior, which indicates the underlying global parameter is not intrinsic to the material, but acquired from its history. Charging behavior is randomly and irreversibly affected by changes in relative humidity, pointing to a mechanism where adsorbates, in particular water, are fundamental to the charge-transfer process.

6 pages, 5 figures. Supplemental information: 3 pages, 2 figures and 2 supplemental videos

References in corpus (4)

• Electrification of granular systems of identical insulators
• Electric Field and Humidity Trigger Contact Electrification
• Self-charging of identical grains in the absence of an external field
• Quantitatively consistent, scale-spanning model for same-material tribocharging

Cited by in corpus (8)

• Asymmetries in triboelectric charging: generalizing mosaic models to different-material samples and sliding contacts
• Triboelectric Charging Model for Particles with Rough Surfaces
• Suppression and Control of Bipolar Powder Charging by Turbulence
• Faraday Cup Measurements of Triboelectrically Charged Granular Material: A Modular Interpretation Methodology
• Multiple charge carrier species as a possible cause for triboelectric cycles
• Electrostatics overcome acoustic collapse to assemble, adapt, and activate levitated matter
• Impact of Initial Charge Distributions on the Kinetics of Charged Particle Coagulation
• Experiments on Settling of Granular and Cohesive Material in Low Gravity