1.School of Chemical Engineering, Nanjing University of Science and Technology, Nanjing 210094, China ?2.School of Material Engineering, Nanjing Institute of Technology, Nanjing 211167, China ?3.Jiangsu Key Laboratory of Advanced Structural Materials and Application Technology, Nanjing 211167, China
Due to the unique response, chemoresponsive shape memory materials (SMMs) have attracted more and more attentions. Chemoresponsive SMMs which mainly include shape memory polymer, shape memory composite and shape memory gel, are reviewed in this paper. Based on the shape memory principles, chemoresponsive SMMs are divided into plasticization recovery SMMs, swelling recovery SMMs, soluble recovery SMMs and pH induced recovery SMMs. Plasticization, as the interaction between solvent molecules and the polymer matrix, reduces the glass transition temperature of polymer and realizes the shape memory effect. Swelling effect is the diffusion of solvent molecules into the polymeric network and induces the free volume of matrix to expand, shape memory is activated by releasing the elastic energy stored during the deformation of temporary shape. Soluble recovery means the constrained elastic phase recovers after switchable phase is soluble and the shape memory is achieved. For pHresponsive SMMs, protonation promotes the motion of the inner segment in a certain pH environment, which drives the energy stored at deprotonation release to achieve the shape memory effect.