A safe and efficient liquid-solid synthesis for copper azide films with excellent electrostatic stability

The traditional gas-solid synthesis of copper azide (CA) always requires rigorous conditions, such as the use of hazardous HN3 gas, and time-consuming preparation processes (>12 h). Both disadvantages impede its ecofriendly large-scale production and result in high safety risks for the practical synthesis. Here, a safe and efficient (<40 min) liquid-solid strategy is developed to fabricate CA films. Employing CuO nanorods (NRs) arrays as precursors, a nest-like CA film with remarkable energetic performance and excellent electrostatic stability can be generated in situ in a NaN3 solution via an electro-assisted azidation method. The resulting CA film possesses an energy release of 1650 J g(-1) and effective detonation performance. In particular, the electrostatic sensitivity (E-50) value (0.81 mJ) is 16 times higher than that of the original CA powder (0.05 mJ), which is attributed to not only the unique nest-like structure of the CA film but also the uniform in situ incorporation of CuO. In addition, density functional theory (DFT) calculations are employed to provide insights into the detailed reaction pathways of the liquid-solid azidation process. Importantly, the constructed CA film can be directly integrated into a micro ignitor to realize nanoenergetics-on-a-chip due to the safe synthetic process as well as its high compatibility with microelectromechanical systems (MEMS) technology.