Facile preparation and energetic characteristics of core-shell Al/CuO metastable intermolecular composite thin film on a silicon substrate

•A facile method is developed to prepare core-shell Al/CuO MIC on silicon substrate.•The method eliminates the cracking problem and suitable for practical applications.•The high exothermicity is validated by thermal analysis and laser ignition test.

Nanostructured energetic composites, in which the oxidizing component and the reducing component are uniformly distributed and intimately contacted, are attracting much attention in recent years. In this study, a new method is developed to facilely prepare CuO nanotubes and accordingly the core-shell structured Al/CuO metastable intermolecular composite (MIC) thin film on a silicon substrate. Cr and Cu thin films are sputter-deposited onto the silicon substrate sequentially, where Cr thin film functions as the adhesion layer. The silicon substrate is then immersed in a mixture of NaOH and (NH4)2S2O8 to form one-dimensional Cu(OH)2 nanostructures, which are then dehydrated at 180 °C to form CuO nanotubes. Nano Al is then sputter-deposited around CuO to obtain core-shell Al/CuO MIC. The morphological, structural and compositional information of the core-shell Al/CuO MIC is characterized by field emission scanning electron microscopy, transmission electron microscopy, X-ray diffraction, and X-ray photoelectron spectroscopy. The energy-release characteristics of core-shell Al/CuO MIC are studied by differential scanning calorimetry and differential thermal analysis, and the preliminary laser ignition test is conducted by using pulsed Nd:YAG laser. The results show that the prepared Al/CuO MIC possesses a fine core-shell structure and is highly exothermic. The preparation method developed is suitable for the facile synthesis of non-cracking core-shell Al/CuO MIC thin film that can be integrated with microelectromechanical systems to realize functional energetic chips.

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