Polyaniline-decorated carbon fibers for enhanced mechanical and electromagnetic interference shielding performances of epoxy composites

[Display omitted] •Polyaniline nanolayer was designed to improve the interfacial interaction in carbon fiber/epoxy composites.•The carbon fiber/epoxy composites showed a superior electromagnetic interference shielding effectiveness of 54.8 dB.•The carbon fiber/epoxy composites exhibited excellent mechanical properties, with an interlaminar shear strength of 72.8 MPa.•An interfacial enhancement mechanism was proposed to explain the excellent mechanical properties of the composites. The development of carbon fiber-reinforced polymers (CFRPs) with high electromagnetic interference (EMI) shielding effectiveness is highly desirable for engineering applications. Nevertheless, poor interfacial adhesion between carbon fibers (CFs) and polymer matrix remains a serious issue. Herein, a mechanically enhanced CF/epoxy composite with highly efficient EMI shielding was fabricated through in-situ polymerization of polyaniline (PANI) nanolayer. The PANI nanolayer improved the interfacial adhesion in the composites via the entanglement of molecular chains, π–π stacking, and chemical bonding et al. The resulting CF/PANI/epoxy composite exhibited an interlaminar shear strength of 72.8 MPa, which was a 24% improvement over 58.5 MPa for the virgin CF/epoxy composite. Moreover, an excellent EMI shielding effectiveness of 54.8 dB was achieved, which was 58% higher than that of the virgin CF/epoxy composite. This could be attributed to the significant enhancement in conduction loss, interfacial polarization loss, and multiple reflections with the help of PANI nanolayer. This study provides a novel strategy for the development of high-performance CFRPs for efficient EMI shielding.