Ultra-transparent, hard and antibacterial coating with pendent quaternary pyridine salt

Pathogenic microbes are ubiquitous, and they can proliferate quickly on wood surface under the suitable conditions to pose a huge hidden threat to public health security and safety. To impart wood surface with outstanding antibacterial activity, we synthesized a pyridine quaternary ammonium (PQAS) monomer by nucleophilic addition reaction between 4-vinylpyridine and 1-bromododecane, and then prepared the cationic antibacterial polymer (CAP) by radical copolymerization. After that, the antibacterial composite emulsion was obtained after uniformly mixing CAP with a commercialized polyacrylate emulsion (PAE). Finally, we obtained an ultra-transparent, hard and antibacterial CAP/PAE coating by brushing CAP/PAE emulsion on the wood surface and then drying at 80 °C for 3 h. And the optimum mixing ratio of coating was explored and explained by using zeta potentialaccording to the theory of polymeric emulsion. Moreover, the chemical structure, antibacterial activity, physicochemical properties, and cytotoxicity of this coating were investigated systematically. The experimental results indicated that the antibacterial activity of CAP/PAE coating against E. coli and S. aureus were greater than 99.9 % without releasing antibacterial components. Even after being irradiated with ultraviolet light at 254 nm for 100 h, its antibacterial rates still reached 97.12 % (E. coli) and 99.35 % (S. aureus), respectively, which are much higher than the required antibacterial rate of Grade 1 (the highest-grade), and superior to most of the reported work. In addition, the CAP/PAE coating exhibited 5H hardness, ultra-transparent, enhanced mechanical properties and low cytotoxicity. Hence, we have developed a facile approach to fabricate multifunctional coating that has potential application in vehicle glass, mobile screens, building wall, furniture and other fields to endow outstanding and rapid bactericidal activity without compromising their appearance physicochemical properties or biocompatibility.