Self-assembly assisted by microdroplet templates confinement for the preparation of ultramixed composite energetic particulates

• Microreaction systems for preparing oxidant and droplet template were constructed. • The effects of reactant conditions on crystal morphology of BaCrO 4 were investigated. • The UV-Vis absorption peak of BaCrO 4 varied with decreasing crystal thickness. • A microdroplet-confined coupling polymer self-assembly theory was proposed. • Homogeneous mixed B/BaCrO 4 microspheres with high delay precision were prepared. Restricted by the macroscopic spatial scale conditions in traditional preparation methods, the improvement of delay precision of the delay composition gradually arrives at the bottleneck. Therefore, a microdroplet-confined coupling polymer self-assembly theory based on microfluidics was proposed to prepare ultramixed self-assembled composite energetic material particulates in order to make a breakthrough in its delay precision. Taking boron (B)/barium chromate (BaCrO 4 ) delay composition as the research object, nano-BaCrO 4 particles were prepared and microdroplet templates were generated by using the micromixing and microdispersing reaction systems respectively. With the excellent mixing efficiency of the micromixing reaction system, the effect of reactant concentration and temperature on crystal morphology and particle size of BaCrO 4 was investigated, and the spectral response of BaCrO 4 particles was analyzed on-line by using an on-line UV-vis spectrophotometer. The results indicated that the reactant concentration exerted a great influence on crystal morphology and particle size of BaCrO 4 , and the characteristic absorption peak of BaCrO 4 was red-shifted regularly with the decrease of crystal thickness at low reactant concentration. Microdroplet templates for self-assembly of B/BaCrO 4 nano-composite particles were generated by using a microdispersing reaction system, and the self-assembled B/BaCrO 4 particulates were prepared. The particulates were characterized by thermal analysis and the delay precision was measured. The results exhibited that the composite energetic particulates with ultra-homogeneous mixing, excellent combustion performance and high delay precision were prepared. In summary, in this study, ultramixed self-assembled B/BaCrO 4 particulates with high delay precision were prepared based on microfluidics, which can provide a novel technology and method for the preparation and mixing of other composites.