Water-borne chitosan/CuO-GO nanocomposite as an antibacterial coating for functional leather with enhanced mechanical and thermal properties

The advancement of eco-friendly and effective antibacterial outer surfaces for medical textiles and leather products is considered important by industries and end users. Herein, positively charged chitosan (CS) and copper oxide nanoparticle-decorated negatively charged graphene oxide (CuO-GO) were assembled layer-by-layer to create an innovative nanocomposite (CS/CuO-GO) coating onto the leather surface. GO was prepared from graphite powder. Eco-friendly synthesis of CuO nanoparticles with <i>Aloe vera</i> leaf extract was reported and utilized to prepare the CuO-GO nanocomposite. The as-prepared materials were tested through FTIR, XRD, UV-vis spectroscopy, TEM, and DLS analyses. Different amounts of CS/CuO-GO coated leathers showed efficient antibacterial activities against <i>Escherichia coli</i> (<i>E. coli</i>) and <i>Bacillus subtilis</i> (<i>B. subtilis</i>) using a "kill-release" approach. This was largely attributed to the cooperative interaction between the contact-killing of the chitosan layer, the discharge of Cu²⁺ ions, and the bacterial-repelling properties of the anionic GO layer. The FE-SEM analysis confirms the existence of a CuO-GO layer on the leather surface with an effect on the macroscopic level performances. The XPS analysis confirms the chemical state of the coated materials on the leather surface. Tensile, tear, and stitch tear strength increased after coating with the CS/CuO-GO nanocomposite. The WVP of the coated leather remains within the range after coating with different wt% of the CS/CuO-GO nanocomposite. The durability of the nanocomposite coating on leather surfaces was thoroughly examined through dry and wet rub fastness tests. Results clearly showed that the strong coating greatly enhanced the antibacterial effectiveness of leather against mechanical wear. The impacts of CS/CuO-GO nanocomposite coating on the leather surface hydrophilicity were evaluated using water contact angle measurements. Water-borne chitosan-based CuO-GO nanocomposite showed a good eco-friendly leather finishing system. It could extend their applications to sports and medical textiles to impart antibacterial effects.