The cooperative mechanism of PDA and THV to improve the dispersibility and combustion of nano-aluminum powder

Fluoropolymer-based surface modification has proven effective in enhancing the combustion efficiency of aluminum (Al) powder. However, the underlying ignition and combustion mechanisms of fluoropolymer-containing nanoaluminum (Al-nm) composites remain poorly understood, limiting the rational design of Al-based additives for solid propellants. Here, Al-nm powder coated with a polydopamine (PDA) interfacial layer and subsequently composited with a tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer (THV), designated as Al@THV, was systematically investigated using an integrated experimental and molecular dynamics (MD) approach. The effects of THV mass fraction on particle dispersibility, oxide layer integrity, agglomeration behavior, and overall combustion performance were evaluated. The PDA coating markedly improves Al-nm dispersion, while THV incorporation effectively disrupts the native oxide layer, suppresses agglomeration, and accelerates energy release. At the optimal THV loading of 30 wt%, the Al@THV composite exhibits superior combustion characteristics, including a flame extension velocity of up to 86 cm/s, as well as significant enhancements in flame area and luminous intensity. ReaxFF MD simulations further reveal that THV facilitates oxide layer breakdown while reducing the reaction energy barrier. These findings provide theoretical and practical guidance for the development of fluoropolymer-composited Al powders in solid propellant systems.