Unlocking enhanced properties: surface-engineered carbon fibers via microwave-grown ZnO nanoflakes for advanced thermoplastic composites

Carbon fiber-reinforced thermoplastic (CFRTP) laminates, particularly CF/PEI systems, are emerging as a transformative and sustainable alternative to conventional thermosets, lauded for their inherent recyclability and exceptional intrinsic properties. To truly unlock their full potential and accelerate their adoption in demanding applications, we have developed a pioneering, facile, and remarkably rapid microwave-assisted methodology for the direct growth of uniform zinc oxide (ZnO) nanoflakes onto carbon fibers. This innovative surface engineering yields an optimized ZnO-CF/PEI laminate that, remarkably, requires just 3 minutes of microwave treatment to achieve extraordinary performance gains. Our results demonstrate a significant and simultaneous enhancement in mechanical strength: a striking 21% increase in interlaminar shear strength, a robust 17% increase in flexural strength, and a substantial 22% increase in storage modulus. This impressive mechanical uplift is directly attributed to the dramatically enhanced interfacial bonding facilitated by the integrated ZnO nanoflakes. Beyond structural integrity, the homogeneously integrated ZnO layer confers exceptional electromagnetic interference shielding effectiveness (EMI SE) of -48 dB, a crucial functional property achieved through amplified reflection and scattering. This work thus presents a straightforward yet profoundly effective strategy to concurrently boost both the mechanical and EMI shielding performance of high-performance thermoplastic composites, directly paving the way for their accelerated deployment in advanced, multifunctional aerospace and industrial applications.