Construction of Chitosan Microcapsules Using Ultraviolet Wood Wax Oil for Self-Healing Antibacterial Wood Coatings

This study reports the development of a dual self-healing, antibacterial, and pH-responsive wood coating using intelligent microcapsule technology. Microcapsules were synthesized with UV wood wax oil (UVW) as the core and hydroxypropyl methylcellulose/TiO2-modified chitosan as the shell, achieving 78.2% encapsulation efficiency. The microcapsules released contents most effectively in a pH 9 water, sustaining release for 1000 h following Fickian diffusion. The coating with 10.0% microcapsules reached a healing efficiency of 83.3% after 8 days at room temperature, while 2.0% microcapsule coatings achieved 42.9% healing under 10 min UV exposure. The 2.0% coating also demonstrated antibacterial activity against Escherichia coli (E. coli) at 75.82%. In addition, it showed minimal yellowing, gloss loss, and color change under cold liquid exposure. The coating exhibited strong mechanical performance, with a load-bearing capacity of 129.363 N, adhesion strength of 8.985 MPa, and maximum elongation at break of 8.87%. These results support the potential of this multifunctional coating for advanced wood surface protection.