Facile water-assisted permanent shape reconfiguration of zwitterionic polyurethanes

There have been great developments in shape memory polymers in recent years. However, the permanent shape was usually predetermined and could not be changed during the shape memory process. This work reports a facile method for permanent shape reconfiguration of shape memory polymers using a water-soaking treatment. The impact of water molecules on the structure, morphology, and properties of zwitterionic polyurethanes (ZPUs) was carefully investigated. FT-IR, DSC, TGA, and DMA analysis revealed that polymer chains of ZPU can be easily activated by absorbing water molecules and was solidified again by removal of water molecules. Direct water-soaking treatment can eliminate previous shape recovery capability and then be used to reconfigure a new permanent shape for a new thermally induced shape memory process. Thus, this work provides an alternative approach for manufacturing complicated devices at room temperature and for easily regulating the thermally induced shape memory effect.