Ultrasensitive and highly stretchable bilayer strain sensor based on bandage-assisted woven fabric with reduced graphene oxide and liquid metal

Abstract

Flourishing flexible and wearable strain sensors still meet a challenge to realize ultrahigh sensitivity and wide working range simultaneously through a convenient strategy. Here, a strain sensor is designed based on natural rubber (NR) matrix and a bilayer structure composed of a highly stretchable liquid metal (LM) layer and a susceptible reduced graphene oxide (RGO)@carbonized bandage (CB) layer. By painting LM onto the surface of a graphene oxide (GO)-coated bandage template followed with a rapid flame pyrolysis, a dual conductive-layer woven fabric based on LM/RGO@CB was obtained. NR was then employed as an elastic substrate. Benefiting from the synergistic bilayer network and the high stretchability of the elastomer, the fabricated strain sensor exhibited ultrahigh sensitivity (gauge factor of up to 1.63 × 105), quite wide detection range (strain of 0 ∼ 515 %), low detection limit (0.25 %), fast response/recovery (135 ms/135 ms), and satisfactory durability (5700 cycles). The extraordinary strain-sensing performance allowed comprehensive monitoring of full-range (vigorous and subtle) human motions and physiological activities. This work provides a facile bilayer strategy for the preparation of high-performance strain sensors.