Bioinspired Superstrong, Wet Adhesive Deep Eutectic Solvent‐Based Gels for Stain Sensing and ECG Monitoring

Abstract

Low mechanical properties and easy detachment from the hydration layer at the wet interface of hydrogel limit its application as an adhesive‐flexible sensor. In this study, the composition and structure of mussel mucoprotein are replicated using sulfonyl betaine (SBMA) containing zwitterion and N‐hydroxyethyl acrylamide to be polymerized in deep eutectic solvents and integrated with a polydopamine network to create a bionic eutectic gel with exceptionally strong and wet adhesion. Water erosion is effectively inhibited by the extensive hydrogen bond and electrostatic interactions. These dynamic bonds also impart self‐healing properties to the gel, showing a self‐healing efficiency of 55.45% after 48 h healing at room temperature. The zwitterion in SBMA can preferentially react with water to form a hydrated shell to protect the hydrogen bonds and enhance the exceptional water resistance and adhesion of the gel. The peel strength of the gel on a wet substrate is up to 220.71 N m−1, and its tensile strength can reach 1.01 MPa. It also has good mass stability at both low and high temperatures. This eutectic gel has the potential to be used in flexible electronic devices and can detect human movement and bioelectrical impulses on wet skin with great sensitivity.