液滴界面可控导入沉淀剂制备单分散均匀微球

均一尺寸微米功能材料在诸如高分子化学、医药化工、催化以及高效分离等领域都受到普遍关注。现有常规方法很难满足制备单分散、均一性的微米材料的要求。采用微流控技术,在微流控芯片内先生成液滴,然后再在线固化液滴的方法,制备了各种单分散、尺寸均一的微球。通过液滴界面受控导入沉淀剂到液滴中,当所含溶质为固化慢的硅溶胶时,生成实心微球,制备得到表面积达572 m²·g^-1、直径变异系数约为2%的纳米孔道二氧化硅微球;当液滴内含沉淀固化较快的溶质,如Zn、Fe、Cu,则可形成水合氧化物或者混合氧化物空心球微球;当含快沉淀也含慢速固化物质时,如含可溶性Fe的硅溶胶时,通过调控沉淀剂进入液滴的速度,也成功了制备了Fe均匀分散在氧化硅内的混合氧化物微球。

Preparation of monodisper microsphere by controlled droplet solidification

Uniform size micromeres functional material gets a lot of attention in the fields of polymer chemistry, medicine and chemical industry, catalysis and separation. It is incovenient to prepare monodisperse and uniformity micrometer material by current conventional technology. With microfluidic technology, the droplet was generated in the chip and following to solidify the droplet online to prepare various of monodisperse and size uniformity microsphere. Since the droplet was a Si sol of slow-solidified, the nonporous SiO₂ microsphere with a BET surface area of 572 m²·g^-1 and a variance coefficient of microsphere diameters of about 2% were produced by introducing precipitator from the interface of droplet. Because the droplets were a material of fast-precipited, such as Zn, Fe, or Cu ion, a hollow microsphere consisted of hydrate oxide or mixed oxide was produced. As the droplet contains both materials of fast-precipitated and flow-solidified, such as Si sol containing of Fe ion, SiO₂ microsphere with a homogeneous dispersed Fe in it was obtained by adjusting the introducing velocity of precipitator into the droplet.