Designing functionalized graphene-stitched-SiC/fluoropolymer novel composite coating with excellent corrosion resistance and hydrogen diffusion barrier properties

The investigation on ordinary hydrogen barrier composite coatings has been limited in terms of corrosion and high-pressure hydrogen environments, which significantly restricts its practical and industrial applications. Herein, a unique nanohybrid two-dimensional (2D) filler, constituting poly-dopamine (PDA) functionalized graphene (Gr) nanosheets and covalently bridged silicon carbide (SiC) nanoflakes assisted by 3-Isocyanatopropyltrimethoxysilane (IPTMS) via hydrolysis reaction, was innovatively proposed and incorporated into fluoroethylene vinyl ether resin (FEVE) to fabricate final composite coating by spin-coating technique. The hydrogen gas barrier and long-term anti-corrosion performances could be simultaneously enhanced by precisely collaborative effects of interfacial interactions fortification among Gr, SiC, and polymer phase as well as centrifugal force promoted Gr orientation during the spinning process. The optimum sample demonstrated high |Z|0.01Hz values of 3.1 × 1011 Ω cm2 and 3.37 × 1011 Ω cm2 throughout 90 d saltwater immersion and 6-day 1.5 MPa pressurized hydrogen environment exposure respectively. Moreover, its permeability coefficient decreased by 75.66% compared to the pure sample. Other significant properties including 30d constant salt-spray attack tolerance and high adhesion strength of 12.46 MPa were also achieved to meet industrial demands. This work provided paramount inspiration for designing composite coatings for hydrogen transportation pipeline protection and hydrogen energy usage.