Constructing the combination bridge of aluminum hydride (AlH3) and polyvinylidene fluoride (PVDF) through the self-assembly of dopamine: Improving the stability and ignition properties of AlH3

Surface coating is an important method to solve the poor stability of aluminum hydride (AlH 3 ). To overcome the difficulty of uneven coating of fluorine-containing polymers on the surface of AlH 3 , this study utilizes the adhesion properties of polydopamine (PDA) to establish a bridge between the oxide layer of AlH 3 (Al 2 O 3 ) and polyvinylidene fluoride (PVDF), so that Polyvinylidene fluoride (PVDF) was uniformly coated on the AlH 3 surface, and a dual-core shell structure AlH 3 @PDA@PVDF composite was successfully prepared. Molecular dynamics simulations reveal significantly higher binding energy per unit area for γ-Al 2 O 3 @PDA/PVDF (1.2270 Kcal·mol −1· Å −2 ) compared to γ-Al 2 O 3 /PVDF (0.6644 Kcal·mol −1· Å −2 ), affirming that PDA can effectively enhance the interfacial interaction between AlH 3 and PVDF. The morphology characterization and performance testing of raw AlH 3 and AlH 3 @PDA@PVDF composite were carried out through SEM, XPS , FT-IR, DSC , VST, etc. The results indicate that through the interface modification of AlH 3 by PDA, PVDF with a hydrophobic surface can be evenly coated on the surface of AlH 3 , causing the water contact angle (WCA) of the AlH 3 @PDA@PVDF composite to increase from 41° for the raw AlH 3 to 124°. Furthermore, the total decomposition time of the AlH 3 @PDA@PVDF composite (2326 min) is improved by 1.8 times than that of the raw sample (1277 min), and its apparent activation energy (117.75 kJ·mol −1 ) was also higher than that of the raw sample (99.88 kJ·mol −1 ), indicating that coating with PDA and PVDF can improve the stability of AlH 3 . Ignition experiments demonstrate that the AlH 3 @PDA@PVDF composite has superior ignition reaction performance compared with the raw AlH 3 . Especially, adding a small amount of AlH 3 @PDA@PVDF composite can also significantly catalyze the thermal decomposition process of ammonium perchlorate (AP), reducing its high-temperature decomposition temperature from 405.37 °C to 352.20 °C.