Innovative surface modification strategy for ADN: PFOA-interlayered and vibrational magnetron sputtering for constructing anti-hygroscopic composite structures

Ammonium dinitramide (ADN), as a high-energy oxidizer widely applied in the field of rocket and missile propellants, has a prominent issue of high hygroscopicity due to its strong polarity. The previous coating encapsulation methods have struggled to address the problems of uneven coating and polarity mismatch. This research innovatively introduces perfluorooctanoic acid (PFOA) as a polar transition intermediate layer. Utilizing the polarity of one end of it to adsorb on the surface of ADN through hydrogen bonds, the problem of polarity mismatch is effectively overcome. Meanwhile, the vibrational magnetron sputtering process has been first applied in the energetic field, with a special vibrating abutment enhancing ADN particle fluidity to solve coating non-uniformity, thus preparing prilled ADN@PFOA@PTFE core-dual-shell composites. Performance tests reveal that this composite material possesses excellent hydrophobic and anti-hygroscopic properties. When left at 25 °C and 75% RH for 3 days, moisture absorption was reduced by more than 90% compared to pure ADN. Simultaneously, its thermal stability, heat release performance, and combustion performance have been improved. The research achievements optimize the storage conditions of ADN in the application of rocket and missile propellants, providing solid support and broad development prospects for technological innovation in military fields.