Coating Architecture Enhances the Combustion and Thermal Behavior of GO–PVDF-Coated Aluminum Powders

To enhance the ignition sensitivity and combustion reactivity of micron-scale aluminum (Al) powder, two composite coating structures─graphene oxide/poly(vinylidene fluoride)/aluminum (GO/PVDF/Al) prepared via sequential deposition and a comixed graphene oxide–poly(vinylidene fluoride) aluminum composite (GO+PVDF/Al)─were fabricated using a spray-drying method. Their coating morphology, thermal behavior, combustion performance, and interfacial reaction mechanisms were systematically investigated. Thermal analysis and combustion testing show that both coating strategies markedly reduce ignition delay and enhance reaction intensity; however, GO+PVDF/Al exhibits the highest heat release, the fastest pressurization rate, and the strongest optical emission. Flame-evolution imaging further demonstrates that the comixed coating more readily promotes vigorous gas–solid coupled combustion. Molecular dynamics (MD) simulations reveal that the GO+PVDF/Al interface is more susceptible to high-temperature perturbations, leading to faster oxide-layer disruption and deeper penetration of oxygen and PVDF decomposition fragments into the Al core, resulting in rapid formation of Al–O and Al–F bonds. Taken together, the experimental and computational results show that the synergistic GO/PVDF coating significantly enhances the thermal reactivity of Al powder, while the GO+PVDF comixed structure achieves the most pronounced combustion enhancement. This work clarifies the combustion-enhancement mechanism of GO/PVDF coatings and provides essential guidance for designing high-activity aluminum-based energetic materials.