Xiang Zhou

Aluminum (Al)‐based alloys have emerged as promising solid fuels for energetic composites (ECs) owing to their multi‐metallic properties. However, their energy release efficiency is severely limited by diffusion‐controlled reaction kinetics. In this work, a novel functionalized mesoporous AlSi alloy fuel is designed via a sequential etching and fluorination strategy and combined with P(VDF‐HFP) to form AlSi/P(VDF‐HFP) ECs. This structure‐engineered design effectively overcomes the kinetic constraints imposed by sluggish diffusion. The mesoporous Si framework catalyzes the decomposition of P(VDF‐HFP) and provides abundant channels for gas transport. Moreover, the dissociation and recombination of F ⁻ on the fluorinated surface are analyzed by XPS, and molecular dynamics calculation shows a stronger binding capability between grafted fluorinated chains and P(VDF‐HFP) through intensive C─F···F─C and C─F···H─C interactions. Remarkably, the optimized ECs exhibit a significant increase in reaction heat compared to the pristine composites, accompanied by a reduction in activation energy. Ignition and closed‐bomb tests further demonstrate substantially enhanced combustion performance and pressurization capability. Based on experimental evidence, a reaction mechanism is proposed. This work provides an accessible pathway for improving the reactivity of alloy‐based ECs.

Strengthening the interfacial contact between the reactive components effectively boosts the energy release of energetic materials. In this study, we aimed to create a close-knit interfacial contact condition between aluminum nanoparticles (Al NPs) and Polyvinylidene fluoride-hexafluoropropylene (P(VDF-HFP)) through hydrolytic adsorption and assembling 1H, 1H, 2H, 2H-Perfluorododecyltrichlorosilane (FTCS) on the surface of Al NPs. Leveraging hydrogen bonding between –CF and –CH and the interaction between C–F⋯F–C groups, the adsorbed FTCS directly leads to the growth of the P(VDF-HFP) coating layer around the treated Al NPs, yielding Al@FTCS/P(VDF-HFP) energetic composites. In comparison with the ultrasonically processed Al/P(VDF-HFP) mixture, thermal analysis reveals that Al@FTCS/P(VDF-HFP) exhibits a 57 °C lower reaction onset temperature and a 1646 J/g increase in heat release. Associated combustion tests demonstrate a 52% shorter ignition delay, 62% shorter combustion time, and a 288% faster pressurization rate. These improvements in energetic characteristics stem from the reactivity activation of FTCS towards Al NPs by the etching effect to the surface Al₂O₃. Moreover, enhanced interfacial contact facilitated by the FTCS-directed growth of P(VDF-HFP) around Al NPs further accelerates the whole reaction process.

In this study, mesoporous silicon nanoparticles (M-Si) were successfully prepared by a magnesiothermic reduction of mesoporous silica nanoparticles, which were synthesized by a templated sol-gel method and used as the precursors. M-Si exhibited a uniform size distribution with an average diameter of about 160 nm. The measured BET surface area was 93.0 m² g⁻¹, and the average pore size calculated by the BJH method was 16 nm. The large internal surface area provides rich reaction sites, resulting in unique interfacial properties and reduced mass diffusion limitations. The mechanism of the magnesiothermic reduction process was discussed. The reactivity of prepared M-Si was compared with that of commercially available non-porous Si nanopowder (with the average diameter of about 30 nm) by performing simultaneous thermogravimetry and differential scanning calorimetry in the air. The results showed that the reaction onset temperature indicated by weight gain was advanced from 772 °C to 468 °C, indicating the promising potential of M-Si as fuel for metastable intermolecular composites.