Structure dependent properties of carbon nanomaterials enabled fiber sensors for in situ monitoring of composites

Carbon nanomaterials enabled fibers have been witnessed as a promising technology for in situ structural health monitoring of polymeric composites. Self-sensing composites were enabled with varied integration strategies, including carbon nanotube (CNT) coated fibers (CNTF), reduced graphene oxide (RGO) coated fibers (RGOF) and carbon fibers (CF). Piezoresistive response of varied sensors was disclosed and showed that gauge sensitivity of RGOF is the highest with a clear two-stage performance from linear to non-linear, while CNTF consistently shows well-organized signal before final fracture. Resin infiltration theory was raised to explain the observed structure–property relationship. For CNTF, resin molecules are permeable to its porous network and form integrated CNT/resin nanocomposites. Comparatively, RGO with large lateral dimension and surface conformability forms the noninvasive network from resin penetration. Based on results analysis and mechanism study, CNTF is more suitable for status recognition and long-term purposes; RGOF is more feasible for early warning of structural damages.