3D printed high-performance spider web-like flexible strain sensors with directional strain recognition based on conductive polymer composites

Inspired by the unique structure of spider web, we designed and prepared a spider web-like strain sensor based on multi-walled carbon nanotubes (MWCNT)/graphene nanoplatelets (GNP)/thermoplastic polyurethane (TPU) conductive polymer composites. Fused filament fabrication (FFF) 3D printing was used to meet the growing demand for flexible electronic devices and overcome limitations with the directional sensitivity of traditional strain sensors. The sensor response exhibited high linearity (R2 = 0.98 at 50% strain), a large strain response range (0–300%), high sensitivity (GF > 10000 at 300% strain), short response time (40 ms), low hysteresis, and good stability (1000 cycles). In addition, due to the special structural design, the sensor identified external forces in different directions. This further expands the application range of the sensor. This work provides valuable guidance for the customized fabrication of flexible strain sensors.