Dynamic layer-by-layer surface self-assembly on aluminum fuel for improving the comprehensive performance of propellants

Aluminum-based fuels generally suffer from poor compatibility with the polymer matrix, low combustion heat and severe agglomeration after combustion, which seriously restrict the overall effectiveness of solid propellants. Herein, due to the synergy of borate ester bonding and unsaturated boron-nitrogen coordination, the highly incompatible fluoride and glycidyl azide polymer (GAP) were orderly aligned on Al to construct novel dynamically layer-by-layer coated aluminum fuel (Al@PFND-B-GAP). The thermal reaction performance of Al@PFND-B-GAP with oxygen was significantly improved, and its heat release was 2.42 times that of Al. In the ignition tests, Al@PFND-B-GAP released multiple bright flames to induce microexplosion with the mushroom cloud morphology, which greatly improved the detonation performance of aluminum powder. When Al@PFND-B-GAP was used for building up the hydroxyl-terminated polybutadiene (HTPB)-based propellants, the agglomeration of the aluminum powder was significantly inhibited after combustion. Even with a solid loading of up to 86%, the dynamic interface via layer-by-layer assembly on Al could simultaneously improve the mechanical properties, combustion performance, and anti-agglomeration of the solid propellant. Our proposed Al@PFND-B-GAP could improve the comprehensive performance of solid propellants. And it was an inspiration for the future construction of multistage dynamic coatings and micro/nano ordered interfaces.