In this study, to improve the safety in the preparation process of energetic materials, vacuum freeze-drying technology is applied to develop nanoenergetic thin films in which Al nanoparticles (Al NPs) are used as the fuel and polyvinylidene fluoride (PVDF) powders act as the oxidant. The whole process effectively avoids high temperature and thus ensures operational safety. The morphology and composition characterizations confirm that Al NPs are dispersed uniformly in the hydrophobic energetic binder, endowing the films with increased water-proof, anti-aging and anti-corrosion characteristics. The results of thermal analysis show that a pre-ignition reaction (PIR) destroys the Al₂O₃ shell and a sharp exothermic peak from the reaction between the exposed Al core and PVDF is found before the melting point of Al. Combustion tests reveal that the film with the highest content of Al NPs possesses the fastest flame propagation speed. The preliminary reaction mechanism obtained by probing the reaction products and intermediates suggests that a two-step reaction exists when the film is slowly heated in N₂, while a competitive reaction between oxidation and fluorination of Al NPs is observed when the film burns in air. These results indicate the promising potential of vacuum freeze-drying technology in manufacturing nanoenergetic materials.

An investigation on the influence of Al/CuO reactive multilayer films (RMFs) additives on exploding foil initiator was performed in this paper. Cu film and Cu/Al/CuO RMFs were produced by using standard microsystem technology and RF magnetron sputtering technology, respectively. Scanning electron microscopy characterization revealed the distinct layer structure of the as-deposited Al/CuO RMFs. Differential scanning calorimetry was employed to ascertain the amount of heat released in the thermite reaction between Al films and CuO films, which was found to be 2024 J/g. Electrical explosion tests showed that 600 V was the most matching voltage for our set of apparatus. The explosion process of two types of films was observed by high speed camera and revealed that compared with Cu film, an extra distinct combustion phenomenon was detected with large numbers of product particles fiercely ejected to a distance of about six millimeters for Cu/Al/CuO RMFs. By using the atomic emission spectroscopy double line technique, the reaction temperature was determined to be about 6000–7000 K and 8000–9000 K for Cu film and Cu/Al/CuO RMFs, respectively. The piezoelectricity of polyvinylidene fluoride film was employed to measure the average velocity of the slapper accelerated by the explosion of the films. The average velocities of the slappers were calculated to be 381 m/s and 326 m/s for Cu film and Cu/Al/CuO RMFs, respectively, and some probable reasons were discussed with a few suggestions put forward for further work.