Mussel-inspired polydopamine-directed crystal growth of core-shell n-Al@PDA@CuO metastable intermixed composites

Over past few years, there has been increased interest in the development of metastable intermixed composites (MICs). As typical high energetic materials, MICs find important applications in aerospace and pyrotechnics. Newly developed methods based on the bioinspired surface modification enables advanced MICs with improved stability, higher energy content, and tunable performances. In this paper, the dopamine has been used to coat nano-sized Al (n-Al), forming a polydopamine (PDA) interfacial binding layer by in-situ polymerization. This interfacial binding layer makes it possible to prevent n-Al from further oxidation, and more importantly, functionalized n-Al with multiple chemical groups. Multiple oxidants could be synthesized on the coated n-Al surface under the direction of PDA on the heterogeneous nucleation and growth of crystals, affording exclusively the core-shell MICs. Typically, core-shell n-Al@PDA@CuO MICs have been fabricated. In comparison to the traditional n-Al/CuO MICs, the resulted n-Al@PDA@CuO showed an improved initial reaction temperature (528.4 °C), enhanced energy release (2934.8 J g⁻¹) and lower combustion temperature (1606 °C). The infrared thermograph results also reveal that the n-Al@PDA@CuO has higher combustion efficiency since the n-Al core and CuO shell are better contacted at a nanoscale.