A highly sensitive and stretchable PVA-based hydrogel strain sensor with facile acrylic elastomer encapsulation

Hydrogel-based strain sensors are highly promising for wearable electronics; however, their practical application is often limited by their low sensitivity and tendency to dehydrate. This paper reports on the development of a high-performance strain sensor that addresses these limitations simultaneously through a synergistic material and structural design. A conductive hydrogel composed of a polyvinyl alcohol matrix, multiwalled carbon nanotube filler, and borax cross-linker is encapsulated using a simple and effective lamination process with a self-adhesive, transparent acrylic elastomer film. This facile encapsulation method provides a robust hermetic seal that ensures environmental stability without compromising device flexibility. The resulting device exhibits a remarkable gauge factor of approximately 172 in the high-strain regime (30–100%), negligible signal drift, and stable performance over prolonged cyclic loading. Furthermore, the encapsulated sensor maintains durability and reliable adhesion under humid or saline conditions, validating its suitability for wearable use. The combination of superior sensitivity, long-term stability, and a scalable, low-temperature fabrication process establishes this work as a practical route toward robust hydrogel-based sensors for soft robotics and human-motion monitoring.