双重热响应离子凝胶的构筑及相行为研究

Traditional intelligent thermal-responsive gel system is limited by the single response mechanism and poor tunable response temperature, and it is difficult to meet the demand of intelligent gel materials in complex scenes. In this study, a simple strategy for the construction of doubly thermo-responsive ionogels is proposed. By crosslinking modified semi-crystalline poly(ethylene glycol) (PEG) in ionic liquid (IL), the doubly thermoresponsive ionogel with both upper critical solution temperature (UCST) and lower critical solution temperature (LCST) phase behaviors are successfully prepared. The UCST phase behavior of ionogel is based on the melting of PEG crystalline. And the LCST phase behavior is caused by the change of hydrogen bond between PEG and IL affected by temperature. In addition, by adjusting the content of binary components, the polymer chain length and the type of ionic liquid, the thermo-responsive temperature of ionogel can be continuously controlled in a large range under these two phase-behavior mechanisms. The phase transition of ionogel is accompanied by a variety of physical and chemical properties, such as optical transmittance, mechanical properties (3.6‒0.1 MPa) and ionic conductivity. The special characteristics of ionogel make it play a significant role in the fields of smart display, wearable device and flexible sensor.