Investigation of self-sensing and interfacial properties of CNT-grown basalt fiber reinforced composites under low-temperature CVD conditions

Composite materials characterized by high strength and low weight are extensively utilized in structural applications. Recent efforts have concentrated on enhancing eco-friendliness and functionality. In this study, basalt fiber (BF) was used as reinforcement, and carbon nanotubes (CNT) were grown on the fiber surface via low-temperature chemical vapor deposition (L-CVD) to produce functional fabrics and composites. To minimize thermal damage to BF, CNT growth was conducted at 400 °C and 450 °C for 15, 30, and 45 min. The CNT layer morphology and growth degree were characterized by scanning electron microscopy (SEM) and electrical resistance (ER), and X-ray diffraction (XRD) confirmed that CNT crystallinity increased with higher growth temperature. CNT-g-BFRP demonstrated up to a 40 % enhancement in interlaminar shear strength (ILSS) compared with pristine BFRP, and self-sensing capability was verified through stress-dependent ER. A 2–2.5 μm CNT layer grown at 450 °C for 15 min exhibited superior sensing but reduced mechanical properties due to BF thermal damage. In contrast, 400 °C for 45 min resulted in a similar CNT layer thickness with excellent self-sensing and improved interfacial strength, avoiding significant degradation. These results demonstrate that controlling growth time under low-temperature CVD conditions is an effective strategy for enhancing the CNT layer crystallinity, interface properties, and multifunctionality of CNT-g-BFRP.