Preparation and properties of CS/P(AM-co-AA) composite hydrogels by frontal polymerization of ternary DES

A deep eutectic solvent (DES) was prepared from choline chloride (ChCl), acrylamide (AM) and acrylic acid (AA); chitosan (CS) was used as a filler, and CS/P(AM-co-AA) composite hydrogels were prepared by frontal polymerization (FP). The hydrogels were characterized by Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM). The mechanical properties, pH responsiveness and conductivity of the hydrogel were studied. The results showed that the mechanical properties of the hydrogel were significantly improved by adding CS, and the tensile strength and compressive strength were increased by 11.61 and 1.65 times respectively due to the increase in number of hydrogen bonds. At the same time, due to the presence of AA, the composite hydrogel has excellent pH response and super high swelling performance under alkaline conditions. The introduction of CS enhanced the conductivity of the hydrogel and gradually increased with the increase of CS content. The conductivity of the hydrogel with CS content of 10 wt% was nearly 160 times that of the hydrogel without CS. In this study, a more convenient and rapid method was proposed to prepare conductive composite hydrogels with excellent mechanical properties and pH responsiveness.