Shape memory effect of chitosan/glycerol composite film in mixed water/ethanol solution

In this paper, a chitosan (CS)/glycerol (GL) composite film was prepared, and the solution-responsive feature of the composite film in a mixed water/ethanol solution was investigated. The composite film began to show obvious shape recovery behavior when the water content of the mixed solution was more than 50% v/v. In mixed solutions, when the molar ratio of water molecules and ethanol molecules was more than 2:1, apart from the combination with the ethanol molecules, the residual water molecules could interact with the CS molecules, promoting the formation of hydrogen bonds. The stress stored in CS molecules was released, and the shape memory effect of the composite film was triggered. In addition, the effect of water content in the mixed solutions on the structural, crystal, thermal stability and mechanical properties of the composite film was characterized. (c) 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 47037.