纳米SiO_(2)微球的制备及其结构与性能研究

Preparation of Nano-SiO_(2) Microspheres and Study on Their Structure and Properties

以十二烷基三甲基溴化铵(CTAB)为表面活性剂,氨水为催化剂,正硅酸乙酯(TEOS)为前驱体,采用工艺简单的氨催化水解法在乙醇/水混合溶剂中制备纳米SiO_(2)微球。利用扫描电镜(SEM)对样品的形貌和粒度进行了表征。结果表明,在其它条件不变的情况下,随着CTAB用量的增加,SiO_(2)微球粒径逐渐增大、粒度分布逐渐变宽;随着醇水比例的降低、TEOS用量及氨水浓度的增加,SiO_(2)微球粒径均先增大后减小;而随着醇水比例的降低,粒度分布先变宽后变窄;TEOS用量的增加,粒度分布先变窄后变宽;氨水浓度的增加,SiO_(2)微球的粒度分布逐渐变宽。制备SiO_(2)微球的最佳醇水比例为0.6∶1,所得微球分散性较好,粒度分布较窄,平均粒径为533 nm。并研究得出CTAB和乙醇在纯水体系中是通过“水包油”体系发生作用。所得微球成膜后的光学性能(透过率为76.06%;雾度为48.35%)满足实际应用,表明其在防眩增透显示屏领域具有潜在的应用价值。

With dodecyl trimethylammonium bromide(CTAB) as the surfactant,aqueous ammonia as the catalyst,and tetraethoxy silane(TEOS) as the precursor,nano-silica microspheres were prepared in an ethanol/water mixed solvent by the simple ammonia catalytic hydrolysis method.The morphology and particle size of the samples were characterized using scanning electron microscopy(SEM).The results showed that,under constant conditions,the particle size of the SiO_(2) microspheres gradually increased and the particle size distribution widened with an increase in the amount of CTAB.Additionally,with a decrease in the alcohol-to-water ratio and an increase in TEOS dosage and ammonia concentration,the particle size of the SiO_(2) microspheres initially increased and then decreased.However,the particle size distribution initially widened and then narrowed with the decrease in the ratio of alcohol to water,while an increase in TEOS dosage initially narrowed and then widened the particle size distribution.Moreover,an increase in ammonia concentration led to a gradual widening of the particle size distribution of the SiO_(2) microspheres.The optimum alcohol-to-water ratio for preparing SiO_(2) microspheres was 0.6 ∶ 1,resulting in well-dispersed microspheres with a narrow particle size distribution and an average particle size of 533 nm.Further studies concluded that CTAB and ethanol interact in the “oil in water” system in the deionized water system.The optical properties(transmittance at 76.06% and haze at 48.35%) of the microspheres after film formation meet the practical application,indicating their potential application value in the anti-glare and antireflection fields of the display screen.