Self-assembling biomimetic coating composed of 1D/2D CNT/polydopamine modified GO hybrid for solving conflict between carbon fiber-epoxy adhesion strength and fracture toughness

Abstract

Tackling the intractable contradiction of interfacial strength-toughness is critical. Herein, shell nacre-mimetic coating composed of carbon nanotube (CNT) reinforced polyether amine (PEA)-polydopamine (PDA) and PDA functionalized graphene oxide (GO@PDA) was self-assembled around carbon fiber via a facile, green, low-cost but effective technique of vacuum filtration to fulfill the amplification of synergy effects of GO and CNTs under the constraint of delicate layered architecture. Contents of CNTs and GO@PDA were compared to optimize the performances. When 0.2 g GO@PDA and 5 ml CNTs were added, amazing growths in interfacial shear strength and fracture toughness of 114.2 % and 348.7 % were achieved, relative to untreated fiber composites. Increase in interfacial adhesion is associated with synergistic interactions of covalent and hydrogen bonds, π-π stacking along with mechanical pinning at interphase, while advance in interfacial toughness assigns with crack propagation, stretching deformation, and breakage of hydrogen bridge and π-π interaction that dissipate energy.