Synergistic Enhancement of Hole–Bridge Structure and Molecular-Crowding Effect in Multifunctional Eutectic Hydrogel Strain/Pressure Sensor for Personal Rehabilitation Training

Abstract

Given the electrical signal transduction capability and excellent biocompatibility, conductive hydrogels are regarded as ideal candidates for high-performance strain/pressure sensors applied in personalized medicine. However, there are challenges in concurrent attainment of flexible hydrogel-based sensors with remarkable conductivity, sensitivity, and reliable stability. Herein, a synergistic strategy based on hole–bridge structure and molecular-crowding effect is proposed to fabricate a multifunctional hydrogel-based strain/pressure sensor. As-prepared eutectic hydrogel displays comprehensive performances of impressive electrical conductivity (2.81 S m⁻¹), boosted mechanical robustness (a tensile strength of 2.95 MPa), and reliable environmental tolerance (≈79.8% water retention at 50 °C for 20 days; frost resistance = −45.3 °C). Notably, the eutectic hydrogel-derived stretchable sensor with effective antibacterial ability exhibits enhanced sensitivity (gauge factor = 4.49) across a wide linear range, supporting the monitoring of joint movement and electrocardiographic signals, along with on-demand photothermal treatment. As a demonstration, the employment of the hydrogel-based stretchable sensor in efficiently conveying information and high-fidelity handwriting recognition is investigated with the assistance of machine learning. This innovative eutectic hydrogel holds high promise for future applications as wearable-smart devices integrated with wireless transmission modules, exhibiting great potential in personal rehabilitation training and healthcare monitoring.