Supramolecular topology controlled self-healing conformal hydrogels for stable human–machine interfaces

Abstract

Soft materials (such as hydrogels) with good conformal capabilities and self-healing properties have shown considerable promise in the area of human–machine interfaces. However, creating wearable hydrogels with excellent adhesion performance, good mechanical characteristics, and stability while monitoring remains a significant challenge. This study presents the strategy of generating supramolecular topology assisted by hydrogen bonds to develop self-healing conformal hydrogels for human–machine interface applications. A_x-HG_y hydrogels with adjustable mechanical and adhesion properties were prepared via an in situ polymerization strategy, introducing adenine, cucurbit[7]uril, and guest molecules into an acrylamide matrix. Via balancing cohesion and adhesion, driven by host–guest supramolecular interactions and hydrogen-bond-based supramolecular interactions, the harmonized double cross-linked networks generate good mechanical strength (120 kPa under fracture strain of 1082%), excellent adhesion strength (higher than 154 kPa), good self-healing performance (93.82% self-healing efficiency within 5 h), and ultra-high monitoring sensitivity (a GF of 32.39 under strain of 800%). As a wearable sensor, the A_2.0-HG_0.15 hydrogel can monitor various types of body motion and physiological signals repeatedly and accurately. It is envisioned that this self-healing conformal hydrogel based on harmonized supramolecular topology will have promising prospects in the fields of soft robots and human–machine interfaces.