Fabrication of Core–Shell Nanohybrid-Structured Hydrogel Sensors with Desirable Mechanical and Antibacterial Properties by Quaternary Ammonium Ionic Liquids with Different Chain Lengths

Hydrogel sensors have found widespread applications in various research areas, including medical monitoring devices, smart robots, and so on. However, traditional hydrogels usually suffer from poor mechanical strength and durability, which shorten their service life. Inspired by the toughening mechanisms, we successfully synthesized polyaniline-coated silica (SiO2@PANI) core–shell particle-toughened p(AM/DMx) (quaternary ammonium ionic liquids, DMx) hydrogel with different chain lengths. More importantly, we investigated different chain length effects on the mechanical properties and antibacterial activity of the DMx-based hydrogel. We found that the optimum chain length was C12, the maxi tensile strength of the hydrogel was 307 kPa, the ultrahigh conductivity was 12.77 mS/cm, and the hydrogel exhibited high sensitivity (GF = 12.75) and excellent antimicrobial properties, which established its potential for usage in a wide array of applications. The p(AM/DM12)-SiO2@PANI hydrogel sensors can sensitively and stably detect human activities, such as finger, wrist, and arm flexion. Furthermore, the obtained hydrogel sensors have the potential to be used in the manufacture of a generation of human activity monitors, electronic skins, and soft electronic devices.