To enhance the performance and safety of energetic materials(CL-20),microfluidic technology has been widely used in the microsphere preparation process.By integrating droplet microfluidics with surface acoustic wave technology,ethyl acetate droplets with exceptional uniformity in size are created.Subsequently,micrometer-sized CL-20/NC energetic microspheres are fabricated using a solvent-nonsolvent recrystallization approach.The droplet generation process is monitored employing a high-speed camera.The results demonstrate that surface acoustic wave technology can effectively regulate the transition of droplet generation modes,averting uncontrollable shifts caused by material precipitation and channel obstructions,thereby ensuring consistent and uninterrupted droplet generation.The morphologies of microspheres with varying particle size,CL-20 contents and NC contents are characterized by field emission scanning electron microscopy(SEM).The findings suggest that diminishing CL-20 content,augmenting NC content,or increasing microsphere size can diminish surface roughness and minimize defects.With the support of surface acoustic wave technology,the coefficient of variation in microsphere size decreases significantly from 39.33％to 7.51％,notably enhancing uniformity.The crystal structure and thermodynamic traits of CL-20/NC microspheres of different sizes are characterized using X-ray diffractometry and thermal analysis.The results indicate that microspheres with a median particle size of 20 μm display superior thermal stability,with a decomposition peak temperature of 229.04℃,surpassing that of microspheres with a median particle size of 7 μm at 228.22℃.Microspheres with a median size of 7 μm exhibit heightened reactivity and energy density,manifesting a higher mass loss rate(84.3％)and heat release(12.05mW/mg)compared to their 20 μm counterparts,which demonstrate a mass loss rate of 80.2％and heat release of 8.84 mW/mg.
acoustofluidics technologyCL-20/NC energetic microspherescoefficient of variation of particle sizethermodynamic properties
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