Transparent Polyurethane Coating with Synergistically Enhanced Antibacterial Mechanism Composed of Low Surface Free Energy and Biocide

ABSTRACT

Recently, antibacterial coatings have gained great attention after the outbreak of COVID-19, thus durable transparent polyurethane (PU) coatings with anti-bacterial and anti-fingerprint performances are highly desired. In this work, the low surface free energy enables the hydroxyl-terminated polysiloxanes modified with quaternary ammonium salts (PQMS) enriched on the surface. The optimal PU-PQMS-40% coating with the thickness of 15 μm displayed 96% light transmittance and can be adopted to diverse substrates. This resultant coating exhibits excellent antibacterial activity against Gram-negative E. coli (99.2%) and Gram-positive S. aureus (98.6%) because of the synergistically enhanced antibacterial mechanism of both low surface free energy (27.54 ± 0.75 mJ·m−2) and quaternary ammonium salts (QAs). It is noteworthy that this antibacterial PU coating is capable of retaining its properties even after being subjected to 210 cycles of abrasion tests, manifesting a superior self-renewability. This coating system with combined features of transparency, antibacterial performance, chemical resistance, and durability make it a promising candidate for applications in the fields of electronic devices, automobile interiors, intelligent glass, and marine antifouling.