Piezoresistive Characteristics of Nylon Thread Resistive Memories for Wearable Strain Sensors

A nylon thread (NT) resistive memory is fabricated by performing a simple dip-and-dry solution process using graphene-poly(3,4-ethylenedioxythiophene):poly(4-styrenesulfonate) (PEDOT:PSS) conductive ink. The piezoresistive characteristics of the NT resistive memory are further evaluated for wearable strain sensors. While a stretching strain (epsilon) is applied to the NT resistive memory, the relative resistance change of low-resistance state (LRS) is found to be higher than that of high-resistance state (HRS). This result implies that the contribution of the local overlapping interconnection change in graphene and PEDOT:PSS materials to the LRS resistance change is greater than that to the HRS resistance change. In addition, through many cycles of repeatedly stretching and releasing the LRS of the NT resistive memory at a fixed epsilon = 7.1%, a gauge factor of approximately 22 is measured and achieved for a highly sensitive and durable strain sensor. Finally, the actual integration of the NT resistive memory into textiles can provide resistive memory and piezoresistive sensor applications simultaneously for wearable electronic textiles.