Enhanced interfacial adhesion of aramid fiber composites by constructing a spider silk inspired nanofiber network at interphase

Poly (p-phenylene terephthalamide (PPTA) are highly regarded for their exceptional mechanical properties and chemical stability; however, their inherently smooth and chemically inert surface severely limits their potential for advanced applications. In this study, we propose a sophisticated surface engineering strategy to significantly enhance the surface performance of fiber. By employing a precisely controlled design of the fiber surface architecture, we integrated homogeneous spider web-like aramid nanofibers (ANFs) to synergistically augment both surface roughness and the concentration of active functional groups. The inert structure of the PPTA fiber surface was first improved by using plasma irradiation, and 3-aminopropyltriethoxysilane (APS) was subsequently used as a bridging agent to enhance the interfacial bonding between the PPTA fibers and the ANFs while repairing the defects on the fiber surface. Benefiting from the large amount of active functional groups as well as improved surface roughness originated form coated homogeneous spider web-like nanofiber network on fiber surface, the performance of fiber composite significantly improved. Specifically, the interfacial shear strength (IFSS) increased from 42.3 MPa to 64.3 MPa, and the interlaminar shear strength (ILSS) improved from the original 51.5 MPa–73.3 MPa, representing increases of approximately 51.9 % and 42.3 %. which is much higher than that of other reported work, while the tensile properties and heat resistance remained almost unchanged. The findings offer a unique method on the design of synergistic hybrid bridging transition strategy addressing the weak interphase in PPTA fiber composites.