Biomimetic, highly adhesive, supramolecular nano-coatings for fire-safe polymeric foams

Constructing fire-protective coatings has been to be an effective strategy for reducing fire hazards of polymeric materials. However, it remains a huge challenge to fabricate high-performance flame retardant coatings with biodegradability, excellent mechanical and thermal properties, as well as strong adhesion. Herein, inspired by snails exhibiting strong adhesion to a variety of surfaces by interfacial hydrogen-bonding, a biomimetic, highly adhesive, supramolecular nano-coating consisting of a tannic acid (TA)-functionalized hexagonal boron nitride nanosheets (TA-BNNS), TA and polyvinyl alcohol (PVA) was prepared by using a hydrogen-bond self-assembly strategy of solvent volatilization regulation. TA-BNNS was prepared via an efficient and green ball milling exfoliation method under mild conditions. Dynamically regulating the hydrogen bonds between PVA and TA molecules through the volatilization of ethanol was to achieve physical cross-linking. Then such a nanocoating was applied for surface treatment of rigid polyurethane foam (RPUF), which exhibiting excellent flame retardant properties. Compared to pure RPUF, the peak heat release rate (PHRR) and peak smoke production rate (PSPR) of the TA/PVA@BNNS coated RPUF were reduced by -52.4 % and -53.4 %, respectively. Therefore, this work provides new approach to the design and manufacture of green, efficient and non-toxic flame retardant materials.