An Ultrasoft Initiator-Free Eutectogel for Strain Sensing and Gesture Recognition Assisted by Machine Learning

With the rapid development of Internet of Things and artificial intelligence technologies, flexible wearable sensors have shown great potential in human-machine interaction and health monitoring fields. However, traditional hydrogel sensors face challenges such as water loss, freezing, and the use of toxic initiators during the preparation process, which lead to biological safety issues. To address these challenges, this paper proposes a green, initiator-free polymerization strategy based on the deep eutectic solvent system composed of choline chloride (ChCl) and D-sorbitol. By utilizing the property that the nitrogen-containing quaternary ammonium group in the ChCl molecule can generate free radicals upon ultraviolet irradiation, this study achieves the rapid polymerization of acrylamide in an initiator-free manner. The prepared eutectogel exhibits high transparency (≈96%), skin-fitting elastic modulus, good antifreezing performance, suitable breathability, and broad-spectrum adhesion. The flexible strain sensor constructed based on the eutectogel has high sensitivity, wide detection range, and good fatigue resistance. Combined with machine learning algorithms, this sensor system achieves a high accuracy (98.5%) of recognizing Curwen gestures. This research provides an innovative approach for developing safe, reliable, and environmentally adaptable intelligent wearable devices and has broad application prospects in intelligent music education and modern human-machine interaction.