Ultra-Stretchable and Environmentally Resilient Hydrogels Via Sugaring-Out Strategy for Soft Robotics Sensing

The adoption of hydrogels in most applications is hampered by their high free water content, which limits their mechanical performance and environmental resilience. Herein, this issue is simultaneously addressed by modulating the state of water and the intermolecular interactions in polyacrylamide (PAM) hydrogels. Specifically, PAM hydrogels are toughened by sugaring-out using a monosaccharide (glucose, G). Glucose is found to facilitate PAM hydrogen bonding and interchain interactions. Meanwhile, the high hygroscopicity of glucose converts some of the free water to bound state, endowing the hydrogels with remarkable resilience to extreme environmental conditions. The PAM-G hydrogels are demonstrated as multimodal sensors for soft robotics. Moreover, PAM-G alcogels produced by solvent exchanging with ethanol are shown as effective opto-mechanical sensors. Notably, all these properties are obtained by the inclusion of glucose, a green additive showing no negative health and environmental effect. Glucose is employed as a green and safe additive for a sugaring-out strategy, which can effectively regulate free water content and intermolecular interactions among the components, leading to high-performance hydrogels. The hydrogel exhibits improved mechanical properties and environmental resilience, demonstrating its versatility as a multifunctional sensor for soft robotics. image