Al@Polytannic Acid/Polyvinylidene Fluoride Nanoenergetic Films for Controlled Combustion

The development of nanoenergetic materials with adjustable reaction performance is the key to achieving controllable ignition and propulsion. It has become one of the research hotspots of scientists in the field of energetic materials. Due to its excellent combustion performance and good film-forming properties, the Al/PVDF energetic system with controllable reactivity has a wide application potential for ignition and propulsion. In this work, an Al@PTA/PVDF nanoenergetic film with tunable performance was successfully prepared by in situ coating a polytannic acid (PTA) interface on the surface of Al nanoparticles (nAl) and a composite assembly with polyvinylidene fluoride (PVDF). The differential scanning calorimetry results show that the main exothermic peak of the Al@PTA/PVDF film is 7.0 °C higher than that of the pure Al/PVDF nanoenergetic film when the coating thickness of the PTA interface is adjusted, and the PTA interlayer can also change the reaction mode of nAl and PVDF to a multiband exothermic. In addition, with the thickening of the PTA interface, the activation energy of the Al@PTA/PVDF film increases from 270.2 to 316.1 kJ/mol, and its average burning rate gradually decreases to 152.68 mm/s. These results indicate that the PTA interface can better control the combustion reaction of Al/PVDF, which will promote its application in the field of controllable combustion and controllable propulsion. It is concluded that the degree of contact and the diffusion length of mass transfer between the reaction components can be changed by introducing an intermediate nanolayer between the fuel and the oxidant, which allows the combustion performance of various composite energetic materials to be adjusted.