Synthesis and Characterization of Loaded Nano/Zinc Oxide Composite Hydrogels Intended for Anti-Mold Coatings on Bamboo

This study investigated the antibacterial activity of nano-zinc oxide (ZnO) composite hydrogels on the types of mold organism that commonly affect bamboo. The nano-ZnO was produced via the in situ method in poly(N-isopropylacrylamide-co-acrylic acid) (P(NIPAm-co-AAc)) hydrogel. The structures and properties were characterized using X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), differential scanning calorimeter (DSC), equilibrium swelling ratio (ESR), deswelling and swelling tests, and antimicrobial activity. The nano-ZnO particles were monodispersed in the P(NIPAm-co-AAc) hydrogel. The concentration of the nano-ZnO was higher in the ZnO/P(NIPAm-co-AAc) hydrogel than in the ZnO/PNIPAm hydrogel. The swelling properties in the ZnO/P(NIPAm-co-AAc) hydrogel were more favorable than those of the ZnO/PNIPAm hydrogel, while the deswelling properties were more favorable in the ZnO/PNIPAm hydrogel. The hydrogels that contained more ZnO nanoparticles demonstrated greater antimicrobial properties against Trichoderma viride and Penicillium citrinum of bamboo, while the all of the hydrogels had much less antimicrobial activity against Aspergillus niger.