Interphase Regulation and Electrothermal Performance of Functional Basalt Fiber/Carbon Nanotube/Epoxy Composites via Heat‐Source Location Control

ABSTRACT Conventional thermal curing of fiber‐reinforced polymer composites relies on heating equipment, causing high energy consumption and slow heat transfer. The electrical insulation of basalt fiber (BF) limits the direct electrothermal curing. In this study, basalt fibers are modified with dopamine hydrochloride and coated with carbon nanotubes (CNTs) to create a functional film. Composite laminates were fabricated using oven curing and electrothermal curing with an embedded or two external functional layers. Polydopamine (PDA) modification improved CNT network stability and in‐plane temperature uniformity. Electrothermal curing reduced energy consumption by 97.1% versus oven curing. External functional film electrothermal cured laminates (R‐FPDA) attained flexural strength of 1239.03 MPa and modulus of 66.76 GPa, increasing by 37.5% and 46.6% respectively, against the unmodified oven‐cured laminate. Interphase measurements and simulations showed that the external double‐sided heat source produces more uniform through‐thickness temperature, enhanced resin flow and infiltration, thicker and more uniform interphases. In R‐FPDA, the BF/EP and BF‐PDA/CNT/EP interphase thicknesses reach 1471.08 and 1550.91 nm, growing by 119.50% and 102.04%, respectively, compared with O‐FPDA. Composites show potential for electrothermal deicing and thermal‐assisted heavy‐oil transport. This work offers an energy‐efficient route for manufacturing multifunctional basalt fiber composites, with potential applications in de‐icing, heavy‐oil transport, and other situations requiring lightweight, controllable heat generation.