Electrostatic spraying of zinc carbonate hydroxide-infused ethylene-tetrafluoroethylene powders: A thermally-induced, VOC-free antibacterial superhydrophobic coating

This study introduces an environmentally friendly method to create a superhydrophobic antibacterial coating using electrostatic powder spraying. The process utilizes ethylene-tetrafluoroethylene copolymer (ETFE) and zinc carbonate hydroxide (ZCH) powders and no organic solvent was used. The resulting coating takes advantage of ETFE's hydrophobic properties and the microstructure generated from ZCH's thermal decomposition, producing a micrometer-scale porous structure with a water contact angle of 165°. It demonstrates strong adhesion to substrates, fulfilling grade 0 standards as per GB/T 9286–2021 / ISO 2409:2020. Following 3 cycles of the falling-sand test, as outlined by ISO/TS 10689:2023, the contact angle impressively remains above 150°, underscoring its extraordinary resistance in contrast to coatings described in literature that typically endure just about 1 cycle. Even after 10 cycles of high-speed water jet impacts following ISO/TS 10689:2023, it maintains a water contact angle of 145°, equivalent to resisting ten years of continuous rainfall based on ISO/TS 10689:2023. The coating's antibacterial effectiveness, stemming from its superhydrophobic characteristics and the antibacterial properties of ZnO produced by ZCH decomposition, achieves inhibition rates of 99.6 % and 99.8 % against E. coli (ATCC 25922) and S. aureus (ATCC 6538) respectively, highlighting its significant potential for practical applications. [Display omitted]