Ultra-fast light repair, ultrasensitive, large strain detection range PDA@RGO/EVA composites fiber flexible strain sensor

Abstract

The sensor fabricated from high-molecular polymer is soft, lightweight, and biocompatible; however, traditional high-molecular polymers suffer from viscoelasticity and poor cycle stability. To address these issues, it is essential to develop flexible matrix materials that can overcome viscoelasticity, ensuring high sensitivity and long-term use under large strains for next-generation wearable intelligent devices. In this study, ethylene-vinyl acetate (EVA) with a shape memory effect was utilized as the substrate for a flexible sensor，the shape memory effect of EVA can eliminate the residual strain generated by each long time of use to improve its service life. A polydopamine@reduced graphene oxide (PDA@RGO)/EVA fiber flexible strain sensor was fabricated through melt extrusion, swelling ultrasound, and in-situ polymerization techniques. The resulting sensor exhibits high sensitivity (gauge factor=1801.21), a wide strain detection range (strain = 193 %), and excellent stability and durability (2000 cycles). Notably, the PDA@RGO/EVA fiber flexible strain sensor demonstrates exceptional dual thermal and light repair functions, with light repair achieving a repair speed of 5 seconds, 100 % electrical performance repair efficiency, and perfect consistency in relative resistance response before and after repair. Furthermore, the PDA@RGO/EVA strain sensor can monitor finger and wrist movements in real-time with high accuracy, highlighting its significant potential application in the wearable technology field.