Stimuli Responsive and Antimicrobial Cellulose-Chitosan Hydrogels Containing Polydiacetylene Nanosheets

Hydrogels were prepared by esterification of chitosan (Cs) with monochloroacetic acid to produce CMCs which was then crosslinked to HEC using citric acid as the crosslinking agent. To impart a stimuli responsiveness property to the hydrogels, polydiacetylene-zinc oxide (PDA-ZnO) nanosheets were synthesized in-situ during the crosslinking reaction followed by photopolymerization of the resultant composite. First, 10,12-pentacosadiynoic acid (PCDA) head groups were stabilized with ZnO nanoparticles in the presence of CMCs-HEC hydrogels in petroleum ether. This was followed by irradiating the composite with Uv radiation to photopolymerize the PCDA to PDA within the hydrogel matrix so as to impart thermal and pH responsiveness to the hydrogel