Physiologically compatible MWCNT-incorporated PNCPG self-healed ionic breathable hydrogel for wearable smart strain sensor application

Abstract

The demand for wearable and flexible strain gauges is gradually increasing owing to their ease of integration with the human body. However, despite technological advancements, these sensors face challenges such as environmental factors, durability concerns, and calibration difficulties. Hydrogels are semi-solids, contain more water than metals or polymers, and are known for their viscoelasticity, ionic conductivity, and shapeability. One of the drawbacks of hydrogel-based sensors is the reduction in conductivity owing to faster dehydration. Herein, we introduce a material combination of poly (vinyl alcohol) (PVA)/NaCl/carbon nanotube (CNT)/polyethylene glycol (PEG)/glycerol (PNCPG) to synthesize an ionic hydrogel that improves electromechanical properties and reduces the pores present in the hydrogel structure. The ionic hydrogel exhibited self-healing properties, allowing the strain sensor to be reused even after tampering. Furthermore, the relative alteration in resistance demonstrated remarkable consistency and dependability when subjected to cyclic strain conditions for successful real-time human motion detection in addition to smart, wearable, flexible strain sensors. The hydrogel exhibited excellent sensitivity to mechanical deformation; as a result, exceptionally efficient stretchy ionic-hydrogel strain sensors offer substantial opportunities for use in flexible human health motions, soft robotics applications, and wearable electronics.