Double-network shape memory organohydrogel prepared by one-pot polymerization

Abstract

Shape memory hydrogels have now garnered considerable attention due to their high deformability and good biocompatibility, making them widely applied in devices such as flexible supercapacitors and intelligent devices. However, a mechanical loss for pure hydrogels is inevitable due to freezing at subzero temperature or swelling under solvent conditions. Also, gels with a single network (SN) often exhibit poor mechanical properties compared with tough double-network (DN) gels. Here, a series of DN heterogeneous organohydrogels were synthesized by one-pot polymerization in an oil-in-water (O/W) emulsion. These organohydrogels display an excellent water-retention capacity, and the DN structure enables the gel to exhibit better mechanical properties than SN organohydrogel. Owing to the solidification effect of the 12-hydroxystearic acid (HSA) gelator, the organohydrogel shows a high compressive strength. The optimized organohydrogel achieves a compression strength of 123.9 kPa at ε = 70%, Young's modulus of 53.25 ± 0.34 kPa, and toughness of 355.32 J m⁻². Moreover, the organohydrogel incorporating reversible oil domains and a high elastic hydrogel matrix exhibits a unique thermo-softening and excellent shape memory features. As a result, the resulting double-network organohydrogels with high mechanical properties, quick recovery, and shape memory capabilities could pioneer new paths for use in intelligent devices, tissue engineering, electronic skin, and soft robotics.