Layer-by-layer-assembled flame-retardant coatings from polydopamine-induced in situ functionalized and reduced graphene oxide

An environmentally friendly chemical method was used to reduce the graphene oxide (GO) and subsequently, noncovalent functionalization of the GO with dopamine hydrochloride was carried out via self-polymerization reaction under a weak alkaline condition. The as-prepared nanocomposite was donated as PDA-rGO and later on, flame-retardant coatings were developed into the flexible polyurethane foams (FPUFs) surfaces using polyacrylic acid, and polyethyleneimine along with PDA-rGO via layer-by-layer assembly. The growth process of the deposited coatings was tailored by altering the pH and concentration of the PDA-rGO suspension. Cone calorimeter test results indicated that PDA-rGO-based coating with three tri-layer deposition effectively reduced the peak heat release rate by 49.3%, the total smoke release by 33.1%, and the peak of release for the production of CO by 46.2% compared to the neat FPUF, which could be attributed to the physical barrier effect of rGO sheets and the free-radical scavenging property of polydopamine.