Anchor-Reinforced Deep Eutectic Solvent Gel With Robust Skin Adhesion and Toughness for Stable Bio-interface

Conventional tough hydrogels generally suffer from high Young's modulus, which severely weakens their mechanical compliance with human skin and further impairs the interfacial adhesion. Herein, a PDMAA-deep eutectic solvent (PDMAA-DES) gel is fabricated by anchoring polymerizable DES onto the network backbone during in-situ polymerization. The synergistic covalent and hydrogen bonding interactions between the solvent molecules and the polymeric matrix drastically boost the cohesive energy of the gel. In conjunction with dense polymer network and macromolecular crosslinking, it resolves the contradiction between high toughness and mechanical compliance (high toughness of 21.36 MJ/m³ and skin compatible low Young's modulus of 200.92 kPa). Combined with abundant surface groups, the gel realizes robust adhesive strength of 2.85 MPa on glass and 390 kPa on pigskin. Besides, doping with dimethyl diallyl ammonium chloride improves the gel's conductivity. This material also presents long-term anti-drying property and electrochemical stability after 10000 cycles. Coupled with its good biocompatibility, the gel is assembled into a wireless wearable sensor, which achieves high precision ECG/EOG signal collection (SNR of 30.09 dB), and outstanding resistance to motion artifacts over commercial hydrogel electrodes. This work offers a facile strategy to construct advanced interfacial materials for wearable dynamic physiological signal monitoring.