Highly Swellable and Stretchable Thermoresponsive Hydrogels Enabled by Functionalized Boron Nitride Nanosheets

Abstract Thermoresponsive hydrogels with high stretchability and large swelling ratio are promising materials for fabricating soft devices, sensors, artificial muscles, etc. However, it remains a challenge to achieve these properties simultaneously within one hydrogel. Herein, highly swellable and stretchable thermoresponsive hydrogels are developed by incorporating functionalized boron nitride nanosheets (f‐BNNSs) into poly(maleic anhydride functionalized β‐cyclodextrin‐ co ‐ N ‐isopropylacrylamide) hydrogel. In such hydrogels, the dynamic host–guest interactions between f‐BNNSs and polymer matrix act as sacrificial bonds to efficiently dissipate energy, and the homogeneous covalent cross‐linking network of polymer leads to a smooth stress propagation, which enables the hydrogels to obtain excellent mechanical properties, such as remarkable strength (up to 0.15 MPa) and outstanding stretchability (up to 1457%). What is more, the resultant hydrogel also exhibits excellent thermoresponsive properties (swelling rate up to 5000% at 25 °C and deswelling rate down to 6% at 50 °C). Thus, this work offers a promising strategy to fabricate highly swellable and stretchable thermoresponsive hydrogels for potential soft actuators and bionic robotics applications.