Magnetic Pickering Emulsions Stabilized by Fe3O4 Nanoparticles

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• 作者：Jun Zhou ; Xiuying Qiao ; Bernard P. Binks ; Kang Sun ; Mingwen Bai ; Yunlong Li ; Yi Liu
• 刊名：Langmuir
• 出版年：2011
• 出版时间：April 5, 2011
• 年：2011
• 卷：27
• 期：7
• 页码：3308-3316
• 全文大小：1017K
• 年卷期：v.27,no.7(April 5, 2011)
• ISSN：1520-5827

文摘

Superparamagnetic Fe₃O₄ nanoparticles prepared by a classical coprecipitation method were used as the stabilizer to prepare magnetic Pickering emulsions, and the effects of particle concentration, oil/water volume ratio, and oil polarity on the type, stability, composition, and morphology of these functional emulsions were investigated. The three-phase contact angle (胃_ow) of the Fe₃O₄ nanoparticles at the oil鈭抴ater interface was evaluated using the Washburn method, and the results showed that for nonpolar and weakly polar oils of dodecane and silicone, 胃_ow is close to 90掳, whereas for strongly polar oils of butyl butyrate and 1-decanol, 胃_ow is far below 90掳. Inherently hydrophilic Fe₃O₄ nanoparticles can be used to prepare stable dodecane鈭抴ater and silicone鈭抴ater emulsions, but they cannot stabilize butyl butyrate鈭抴ater and decanol鈭抴ater mixtures with macroscopic phase separation occurring, which is in good agreement with the contact angle data. Emulsions are of the oil-in-water type for both dodecane and silicone oil, and the average droplet size increases with an increase in the oil volume fraction. For stable emulsions, not all of the particles are adsorbed to drop interfaces; the fraction adsorbed decreases with an increase in the initial oil volume fraction. Changes in the particle concentration have no obvious influence on the stability of these emulsions, even though the droplet size decreases with concentration.