Horozov Tommy S, Binks Bernard P, Gottschalk-Gaudig Torsten
Surfactant & Colloid Group, Department of Chemistry, University of Hull, Hull, UK HU6 7RX.
Phys Chem Chem Phys. 2007 Dec 28;9(48):6398-404. doi: 10.1039/b709807n. Epub 2007 Sep 17.
Partially hydrophobised fumed silica particles are used to make silicone oil-in-water emulsions at natural pH of the aqueous phase. The stability and rheological properties of the emulsions and suspensions are studied at NaCl concentrations in the range 0-100 mM. It is found that all emulsions are very stable to coalescence irrespective of the NaCl concentration. However, a strong effect of electrolyte on the creaming and rheological properties is observed and linked to the particle interactions in aqueous suspensions. The creaming rate and extent are large at low electrolyte concentrations but both abruptly decrease at salt concentrations exceeding the critical flocculation concentration of the suspension (approximately 1 mM NaCl). The drastic improvement of the stability to creaming is attributed to the formation of a visco-elastic three-dimensional network of interconnected particles and emulsion droplets.
部分疏水化的气相法二氧化硅颗粒用于在水相的自然pH值下制备水包硅油乳液。在NaCl浓度范围为0 - 100 mM的条件下研究了乳液和悬浮液的稳定性及流变学性质。发现所有乳液对聚结都非常稳定，与NaCl浓度无关。然而，观察到电解质对乳析和流变学性质有强烈影响，且这与水悬浮液中的颗粒相互作用有关。在低电解质浓度下乳析速率和程度较大，但在盐浓度超过悬浮液的临界絮凝浓度（约1 mM NaCl）时两者均突然降低。对乳析稳定性的显著改善归因于相互连接的颗粒和乳液滴形成了粘弹性三维网络。
