Silica aerogel microspheres are known for their unique features which are better than those of the bulk silica aerogel, including excellent biocompatibility and flowability, and have a broader application prospect for biomedicine, adsorption purification, catalytic reactions, energy storage, and sensing. However, the production of high-quality silica aerogel microspheres still poses significant challenges, such as low sphericity, difficult size adjustment, uneven morphology, and a prolonged drying process, especially ambient pressure drying for several hours. Herein, we report a novel process for efficiently synthesizing high-quality silica aerogel microspheres through the use of microfluidic and ambient pressure drying techniques. In the novel process, the colloidal sol microdroplets were prepared in stepped T-microchannels to achieve size adjustment with a narrow diameter distribution and good sphericity. A new drying process under ambient pressure at high temperature was proposed, which realized the rapid drying under ambient pressure for 10 min while the linear shrinkage of the microspheres was less than 5%. Highly spherical and uniform silica aerogel microspheres with diameters adjustable from 50–300 μm were successfully fabricated. The prepared silica aerogel microspheres exhibited high mesoporosity along with ultralow density, high specific surface area, and high hydrophobicity. In addition, the factors that significantly influence the final morphology of the silica aerogel microspheres have been thoroughly researched. This innovative process offers a new approach for the efficient synthesis of high-quality silica aerogel microspheres.

中文翻译：

---

通过微流体和快速环境压力干燥高效制备形状良好的单分散二氧化硅气凝胶微球


二氧化硅气凝胶微球以其优于本体二氧化硅气凝胶的独特特性而闻名，包括优异的生物相容性和流动性，在生物医学、吸附纯化、催化反应、储能和传感方面具有更广阔的应用前景。然而，高质量二氧化硅气凝胶微球的生产仍然面临重大挑战，例如球度低、尺寸调整困难、形态不均匀以及干燥过程延长，尤其是常压干燥数小时。在此，我们报道了一种通过使用微流体和环境压力干燥技术高效合成高质量二氧化硅气凝胶微球的新工艺。在新颖的工艺中，在阶梯式 T 型微通道中制备胶体溶胶微滴，以实现直径分布窄、球形度好的尺寸调整。提出了一种新的常压高温干燥工艺，实现了常压下快速干燥10 min，微球线性收缩小于5%。成功制备了直径可在 50-300 μm 范围内调节的高度球形和均匀的二氧化硅气凝胶微球。制备的二氧化硅气凝胶微球表现出高介孔性以及超低密度、高比表面积和高疏水性。此外，对二氧化硅气凝胶微球的最终形态有显著影响的因素也得到了深入研究。这种创新工艺为高效合成高质量二氧化硅气凝胶微球提供了一种新方法。