Bio-inspired interfacial chemistry for the fabrication of a robust and functional graphene oxide composite film

A strong and functional artificial nacre film is developed by using polyethyleneimine-functionalized GO (PEI-GO) and pyrogallol (PG) inspired by insect exoskeleton sclerotization. PEI-GO is macroscopically assembled into the laminated films and then reacted with PG under the optimized condition for their efficient cross-linking through Schiff-base reactions. The internal structure and physicochemical properties of PG-treated PEI-GO (PG@PEI-GO) films are systematically explored with various analytical tools. The optimized PG@PEI-GO films exhibit excellent tensile strength, modulus, and toughness of 216.0 ± 12.9 MPa, 17.0 ± 1.1 GPa, and 2192 ± 538.5 kJ m⁻³ which are 2.7, 2.8, and 2.3-fold higher than those of GO films, respectively. Furthermore, silver nanoparticles (AgNPs) are densely immobilized on the PG@PEI-GO films harnessing their abundant amine groups, and the AgNPs immobilized PG@PEI-GO films exhibit a high catalytic activity in the conversion of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) with maintaining structural integrity. Based on the results, we demonstrate that the rational design of interfaces, inspired by natural materials, is an efficient approach to achieving strong and functional GO laminated composite films.