A Wearable Strain Sensor Based on Electroconductive Hydrogel Composites for Human Motion Detection

Hydrogels are becoming the default platform for flexible electronic applications—specifically, strain sensors. But the simultaneous realization of compliance, robustness, and strain sensitivity required, using environmentally friendly materials, remains challenging. Here a series of poly(vinyl alcohol) (PVA)‐based biocomposite hydrogels, comprising variable quantities of nanocellulose and sodium alginate formed by freeze/thaw cycling, is reported. The results indicate that a hybrid hydrogel is prepared via the incorporation of conductive polypyrrole/bacterial nanocellulose composite material into the optimized PVA‐based hydrogel matrix (yield strength = 6.0 MPa, elastic modulus = 2.4 MPa, stretchability >384%). The resulting hybrid material exhibits remarkable toughness, nonlinear conformability, and piezoresistivity and demonstrates good strain sensitivity over a considerable range of deformation (