Preparation of microstructure controllable Al/WO3/F2603 MICs by droplet microfluidic technology to improve combustion performance

•The preparation of metastable intermolecular composites by droplet microfluidic technology is proposed.•Al/WO3/F2603 composites with controllable microstructure were prepared.•The self-assembly formation mechanism of Al/WO3/F2603 composites was revealed.•Spherical, bowl-like and wrinkled Al/WO3/F2603 composites have excellent combustion properties. The microstructure of metastable intermolecular composites (MICs) is crucial for their energy release and combustion performance. In this paper, Al/WO3/F2603 composites with controllable microstructure were prepared by droplet microfluidic technology. The microstructure control method of composite materials based on droplet microfluidic technology (DMT) was studied. Particles with controllable size, shape, composition, structure and function were prepared by droplet template, and the formation mechanism of particle microstructure was introduced. The Al/W/F-2 composites with high-quality spherical encapsulation have excellent flow properties and wettability. The ignition delay, combustion time and pressure output of the composites were monitored by a combustion and pressure test system. Compared with the physically mixed samples, the Al/W/F-x composites prepared by DMT have shorter ignition delay, shorter combustion duration, and higher pressurization rate. The analysis of combustion products showed that the encapsulated Al/W/F-x composites reduced the sintering and agglomeration of reactants and promoted the combustion efficiency. The results show that the characteristic structure design of the composite material can establish the interface synergy, enhance the thermal mass transfer between the components, and thus reduce the ignition delay and improve the combustion performance. DMT can realize the controllable preparation of composite microstructure, which provides a reference for the design and preparation of other composite materials.