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Influence of Wettability and Geometry on Contact Electrification between Nonionic Insulators
Ignaas S M Jimidar1,2, Wojciech Kwiecinski3, Gijs Roozendaal3
1Department of Chemical Engineering, Vrije Universiteit Brussel, Pleinlaan 2, 1050 Brussels, Belgium.
ACS Applied Materials & Interfaces
|June 30, 2023
Summary
Relative humidity significantly enhances charge transfer in contact electrification, boosting triboelectric nanogenerator (TENG) performance. This study reveals how water influences charging dynamics, even at high humidity levels.
Area of Science:
- Surface Science
- Triboelectricity
- Nanogenerators
Background:
- Contact electrification involves charge exchange between surfaces upon contact, forming the basis for triboelectric nanogenerators (TENGs).
- The precise mechanisms, particularly the influence of relative humidity (RH), remain incompletely understood.
Purpose of the Study:
- To investigate the role of water and relative humidity in the charge exchange process during contact electrification.
- To elucidate how varying RH affects charging dynamics and TENG performance.
Main Methods:
- Utilized the colloidal probe technique to study charge transfer between two distinct insulators with differing wettability.
- Conducted experiments under ambient conditions with contact and separation times less than 1 second.
Main Results:
- Demonstrated that water plays a crucial role in charge exchange, with charging speed and acquired charge increasing with RH.
- Observed enhanced charging beyond 40% RH, attributed to geometrical asymmetry (curved colloid vs. planar substrate).
- Determined that the charging time constant decreases as RH increases, with enhanced charging observed up to 90% RH for hydrophilic surfaces.
Conclusions:
- Humidity significantly impacts solid-surface charging, enhancing the process up to 90% RH under specific geometric conditions.
- Findings provide insights for designing more efficient TENGs, eco-energy harvesting devices, self-powered sensors, and tribotronic systems.
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