Under-water ignition and combustion of PDMS processed Al/CuO nanoparticle composite

This study investigates the fabrication and performance of hydrophobic nanothermite powders prepared by combining liquid polydimethylsiloxane (PDMS) prepolymers with thermite powders in a dispersion medium. The resulting composite remained dry when submerged underwater and could be ignited by laser irradiation. High-speed imaging measurements showed an ignition delay of 2.3 ms under underwater conditions. Finite-element simulations based on a two-phase flow model revealed rapid cooling and condensation of water vapor during ignition. Preliminary analysis of the bubble composition suggests the evolution of gaseous products from the thermite reactions. These results demonstrate the feasibility of underwater laser ignition of thermite–PDMS composites and provide insights into the complex physical and chemical processes involved in underwater combustion.