Chitosan for constructing stable polymer-inorganic suspensions and multifunctional membranes for wound healing

Restricted by the rigid chain structure, chitosan-based materials are very fragile and easy to break up. Herein, a stable and positively charged chitosan/Ti₃C₂T_x suspension was successfully constructed by adjusting mixing sequence, pH and ratio of chitosan to Ti₃C₂T_x to prepare a multifunctional membrane (P-CM) with self-standing ability, good flexibility, biocompatibility, excellent photothermal antibacterial properties, and sensitive humidity sensing properties. In the first stage, protonated chitosan acted as sugar coatings was able to be encapsulated on the surface of Ti₃C₂T_x nanosheets by electrostatic self-assembly, in turn achieving charge reversal of the nanoparticles. In the second stage, chitosan acted as molecular needles to suture the membrane formed by chitosan/Ti₃C₂T_x particles via vacuum filtration (VAF) with the commercial flexible poly(vinylidene fluoride) (PVDF) membrane. The as-prepared P-CM membrane simultaneously solves the problem of insufficient flexibility of a single component chitosan membrane and the poor bonding between pure Ti₃C₂T_x membranes and substrate membrane.