Fabrication of chitosan-encapsulated microcapsules containing wood wax oil for antibacterial self-healing wood coatings

Wood multifunctional smart coating is a new functional coating that combines smart material technology with traditional wood. In this study, wood wax oil based on thistle oil and flaxseed oil was used as the core material, and chitosan was used as the wall material to prepare self-repairing antibacterial microcapsules. The optimal preparation conditions were found to be an oil-water ratio (OWR) of 2:1, a core-to-wall ratio of 3:1, using OP-10 as the emulsifier at a concentration of 10.0 %, and a crosslinker concentration of 0.18 g/mL. The encapsulation efficiency of microcapsules was 73.7 % by spray drying, and the thermal stability was improved. The chitosan microcapsules exhibit the characteristics of water sensitivity and acid selective response, with rapid release at pH 7.0. Blending microcapsules at concentrations of 2.0 %, 5.0 %, and 8.0 % with UV topcoat and applying them to walnut plywood resulted in a multifunctional wood coating. Artificially simulated daily scratch damage was effectively repaired within 7 d. Furthermore, the 10.0 % microcapsules demonstrated antibacterial properties against Escherichia coli (E. coli) and Escherichia coli (E. coli), with an antibacterial E. coli and S. aureus rate of up to 75.82 % and 42.96 %. The IC50 of the wood coatings against E. coli was 5.667, while against S. aureus it was 15.45. The minimum inhibitory concentration (MIC) of the microcapsules against both E. coli and S. aureus was 10.0 %. The coating film containing 2.0 % microcapsules demonstrated superior overall performance. This research established a foundation for the development of self-healing antibacterial coatings for wood and addressed the gap in dual-functional self-healing antibacterial paint films for wood.