Flowing Water Enables Steerable Charge Distribution on Electret Surface

Contact electrification has been studied since as early as 2,600 years ago, but its mechanism is still unclear, especially for liquid-solid cases. In this paper, an innovative water charging method is proposed for the first time. The charge-transfer mechanism is suppressed by the steerable oxygen plasma treatment, and the 3D charge distribution map of NPU shape is obtained through the surface potential scanner. The method was further applied to the DEG and a self-powered thin-film sensor with droplet position monitoring function was prepared. This study demonstrates the feasibility of the proposed water charging method and proposes a new application in the field of water energy harvesting.