Preparation of reactive thin film consisting of diazodinitrophenol particles and its reaction characteristics ignited by pulse laser ablation

We have prepared reactive thin films by using primary explosive particles with organic material as a binder. Thin films of 20 μm to 750 μm in thickness were prepared by the bar-coater method and also by pour the solution and dry process (PAD method). Diazodinitrophenol (DDNP) particles we have used are 10 μm in size and are fixed by cellulose triacetate (CTA). We chose dichloromethane as the solvent of CTA. By varying the mass ratio of solute to solvent materials in the bar-coater method, DDNP-CTA texture can be controlled. Ignition tests were performed for reactive thin films prepared in this study. Pulse laser ablation of thin film surface and successive reaction process have been observed by two different high speed cameras with different optics. Reactivity was found to depend on the laser irradiation direction at least in case of films of multi-layered structure manufactured by PAD method with thickness more than 100 μm. No detonation reactions were realized among tested reactive thin films and the experimental conditions. We have found the following peculiar combustion process. Combustion of the film takes place in three stages: (i) DDNP particles are ejected from both surfaces of the film by pulse laser ablation of the surface, (ii) induced air shock wave leads to the combustion of these particles, and (iii) finally film body starts to react due to residual thermal energy of itself and adjacent high temperature region created by burning particles.