Biocide-Free Antifouling on Insulating Surface by Wave-Driven Triboelectrification-Induced Potential Oscillation

A biocide-free antifouling method on wetted insulating surfaces, enabled by the oscillation of electric potential generated by an integrated triboelectric wave harvester (I-TEWH) is reported. Distinct from previous studies that reported antifouling on conducting surfaces by applying an additional power source, this method achieves antifouling on insulating surfaces with zero-power consumption. The electric potential in the vicinity of a protected surface oscillates in large amplitude as a result of periodically accumulated free electrons on an underlying electrode. The dynamic flow of the free electrons is driven by the I-TEWH that converts ambient wave energy by solid-liquid interface triboelectrification. As a consequence, the oscillating electric potential disturbs the inherent charge distribution on microbes due to electrostatic induction, preventing their initial adhesion onto the protected surface and thus prohibiting the subsequent formation of macroorganisms. Significant anti-adhesion efficiencies of as high as 99.3%, 99.1%, and 96.0% are achieved for negative-gram bacteria (Escherichia coli), positive-gram bacteria (Staphylococcus aureus), and diatoms (bacillariophyceze), respectively, on a smooth surface. The antifouling efficiency on a roughened surface with micro/nanostructures can be further enhanced by another 75%. This approach can be potentially utilized in coastal constructions, offshore facilities, and vessels that are either moving or stationary in port.