Fabrication of multiple protective fabric based on ZnO/chitosan composite microcapsules via thiol-ene click modification

Chitosan is a green substance that has antibacterial, non-toxic, and good biocompatibility properties. It is becoming more and more popular in the food, pharmaceutical, and textile industries. In this work, paraffin@chitosan microcapsules were synthesized through a single coacervation method, then modified zinc oxide (ZnO) nanoparticles were grafted onto paraffin@chitosan microcapsules to prepare ZnO/chitosan composite microcapsules through Michael addition reaction. The obtained ZnO/chitosan composite microcapsules were further treated on the wool fabric via a thiol-ene click reaction. After treatment, cuticle layers of wool fibers became tender, and the wool fiber surface was covered with ZnO/chitosan composite microcapsules. The bacterial inhibition rates of treated wool fabric could reach 98.9% and 97.2% against the gram-positive bacteria (Staphylococcus aureus) and gram-negative bacteria (Escherichia coli), which was attributed to the synergistic antibacterial effect of chitosan and ZnO. The treated wool fabric also presented enhancement of superhydrophobicity with a water contact angle of 160.9°. Furthermore, the thermal imager analysis of treated wool fabric illustrated that it had a good thermal energy storage performance due to the loaded paraffin.