Graphene Decorated Fiber for Wearable Strain Sensor with High Sensitivity at Tiny Strain

Abstract It remains a challenge to achieve high sensitivity and a broad linear strain range simultaneously for wearable strain sensors. Specially, graphene‐based strain sensors always exhibit low sensitivity owing to the slippage of graphene flakes. To overcome this problem, Al³⁺ is used here as “mortars” for graphene flakes instead of polymers usually used in the literature, and thus a very simple and low‐cost strategy is developed to prepare a high‐performance reduced graphene oxide coated fiber strain sensor. The strain sensor shows a low detection limit (0.1% strain), high sensitivity, and a very broad linear sensing range (0–20%, R² = 0.99, GF = 322), which is attributed to the occurrence of uniform microcracks under stretching induced by Al³⁺ as well as the large variation of the overlapped area between adjacent graphene flakes at small strain (<1% strain). Moreover, the good cycle stability and durability against water washing of the strain sensor are verified. The excellent properties of the wearable strain sensor ensure it successfully applied in the real‐time monitoring of human activities.