自模板法与溶胶-凝胶法相结合制备SiO_2包覆的对甲氧基肉桂酸辛酯微球

Synthesis of SiO_2-coated Octylmethoxycinamate Microspheres with the Combination of Sol-gel and Self-templating Methods

为了弥补对甲氧基肉桂酸辛酯(OMC)易被光降解的缺点,提高其与皮肤的相容性,利用自模板法与溶胶-凝胶法相结合制备以OMC为核,SiO2为壳的纳米微球.得到的核/壳微球具有光滑的表面、规整的球形形态及明显的核/壳结构.在本方法中,首先通过溶胶-凝胶法制备SiO2胶体粒子,作为核/壳微球的前驱体,并对其制备过程进行了优化,得到了最佳的H2O/Si摩尔比及酸的用量.然后利用自模板法使乳液液滴外表面首先被固化,以其自身作为模板,制备了OMC/SiO2核/壳纳米微球.并利用傅里叶红外光谱、透射电子显微镜、扫描电子显微镜、紫外-可见吸收光谱、低温氮气吸附法、X射线光电子能谱、热重分析以及四球摩擦磨损试验法对核/壳微球进行表征.

As a commonly used UV absorber,octylmethoxycinamate(OMC)was added into cosmetics to improve sun protection factor.However,excess additions may cause skin troubles and deteriorate quality of the cosmetics.SiO2-coated nanoparticles were highly demanded to give satisfaction in utility,stability and safekeeping as well as untroubled of skin.In this paper,core/shell nanospheres with OMC as core and SiO2 as shell were prepared through the combination of sol-gel and self-templating methods.The as-prepared samples were characterized by transmission electron microscopy(TEM),scanning electron microscopy(SEM),FT-IR spectrometry, X-ray photoelectron spectrometer(XPS),thermogravimetry(TG)and a four-ball friction and wear test.The effects of the reaction conditions(amount of hydrochloric acid,H2 O/Si molar ratio)on the structure and morphologies were investigated.During the process,SiO2 colloid was first prepared with the sol-gel method and the optimal reaction conditions were obtained.The optimal H2 O/ Si molar ratio and the amount of hydrochloric acid(0.166mol/L)used in the present study were in the range of 1.5-1.7and 1.2-2.4 mL,respectively.And then the core/shell nanospheres were prepared by a rapid solidification reaction from the outer surface toward the center of the emulsion.Experimental results indicated that the resulting nanospheres were perfectly spherical with smooth particle surfaces and had distinct core/shell structures.