Highly stretchable and compressible shape memory hydrogels based on polyurethane network and supramolecular interaction

We synthesized a new type of PU hydrogel via a simple free radical polymerization, where double bond terminated-WPU (waterborne polyurethane) as the first crosslinker, N,N-methylene bisacrylamide (MBA) as the second cross-linker and MAH-β-CD (maleic anhydride modified β-cyclodextrin) as noncovalently crosslinker, which formed hydrogen bonds with GO and host-guest interaction with WPU. The tensile strength and compressive strength are over 500 kPa and 2.5 MPa at the optimal proportion. By changing the ratio of the chemical component, we synthesized WPU hydrogels with high tensile strength and fracture elongation and surprisingly the swollen hydrogel has excellent compressive properties and fatigue resistance performance.