Lovingood Derek D, Owens Jeffrey R, Seeber Michael, Kornev Konstantin G, Luzinov Igor
Oak Ridge Institute for Science and Education.
J Vis Exp. 2013 Dec 16(82):e51022. doi: 10.3791/51022.
Microwave-assisted synthetic techniques were used to quickly and reproducibly produce silica nanoparticle sols using an acid catalyst with nanoparticle diameters ranging from 30-250 nm by varying the reaction conditions. Through the selection of a microwave compatible solvent, silicic acid precursor, catalyst, and microwave irradiation time, these microwave-assisted methods were capable of overcoming the previously reported shortcomings associated with synthesis of silica nanoparticles using microwave reactors. The siloxane precursor was hydrolyzed using the acid catalyst, HCl. Acetone, a low-tan δ solvent, mediates the condensation reactions and has minimal interaction with the electromagnetic field. Condensation reactions begin when the silicic acid precursor couples with the microwave radiation, leading to silica nanoparticle sol formation. The silica nanoparticles were characterized by dynamic light scattering data and scanning electron microscopy, which show the materials' morphology and size to be dependent on the reaction conditions. Microwave-assisted reactions produce silica nanoparticles with roughened textured surfaces that are atypical for silica sols produced by Stöber's methods, which have smooth surfaces.
采用微波辅助合成技术，通过改变反应条件，使用酸催化剂快速且可重复地制备了纳米颗粒直径在30 - 250 nm范围内的二氧化硅纳米颗粒溶胶。通过选择与微波兼容的溶剂、硅酸前体、催化剂以及微波辐照时间，这些微波辅助方法能够克服先前报道的使用微波反应器合成二氧化硅纳米颗粒所存在的缺点。硅氧烷前体使用酸催化剂HCl进行水解。丙酮是一种低损耗角正切溶剂，可介导缩合反应，并且与电磁场的相互作用最小。当硅酸前体与微波辐射耦合时，缩合反应开始，从而形成二氧化硅纳米颗粒溶胶。通过动态光散射数据和扫描电子显微镜对二氧化硅纳米颗粒进行了表征，结果表明材料的形态和尺寸取决于反应条件。微波辅助反应产生的二氧化硅纳米颗粒具有粗糙的表面纹理，这与通过斯托伯方法制备的具有光滑表面的二氧化硅溶胶不同。
