纳米二氧化硅的疏水改性及其对Pickering乳液的稳定作用

为了探究固体粒子对乳液的稳定作用,采用L-赖氨酸作为催化剂合成纳米SiO2粒子,并用六甲基二硅胺烷(HMDS)对纳米SiO2粒子进行表面疏水改性,将经过HMDS改性后的纳米SiO2粒子作为稳定剂制备出Pickering乳液。通过粒径分析仪、场发射透射电子显微镜、FTIR、TG-DSC、接触角测量仪、光学显微镜、电导率仪分别对纳米SiO2的制备、表面改性和Pickering乳液的性能进行了表征。结果表明,成功合成出粒径小且形貌均一的硅球,具有疏水性的三甲基硅基成功接枝到纳米SiO2的表面;不同纳米SiO2浓度制备的Pickering乳液,发现随着SiO2浓度的增大,乳液的稳定性逐渐增强,乳液液滴直径呈现减小的趋势;不同油水比制备的Pickering乳液,发现随着油相体积的增大,乳液的稳定性呈现增大的趋势。

Hydrophobic Modification of Nano-silica and Its Stabilizing Effect on Pickering Emulsions

In order to explore the stabilizing effect of solid particles on the emulsions, nano-silica was synthesized by using L-lysine as the catalyst, and was modified by hexamethyldisilazane in order to obtain hydrophobic performance. Pickering emulsions were prepared by nano-silica acting as stabilizer which was modified by HMDS. The preparation, surface modification of nano-silica and properties of Pickering emulsions were characterized by particle size analyzer, HRTEM, FTIR,TG-DSC, contact angle, optical microscope and electrical conductivity meter respectively. The results showed that the silica spheres with small particle size and uniform morphology were successfully synthesized, and the hydrophobic bond of trimethylsilyl was successfully grafted onto the surface of nano-silica. For Pickering emulsions prepared by different concentration of nano-silica, the stability of emulsions increased gradually with the increase of concentration of nano-silica. Meanwhile, the droplet diameter of emulsions decreased with the increase of concentration of nano-silica. Pickering emulsions prepared by different oil/water ratio, we can conclude the stability of the emulsions increased with the increase of oil phase volume to some extent.