372550 Hydrophobized Colloidal Silica: Effect of Functional Group and Surface Coverage on Particle Wettability and Pickering Emulsion Stabilization

Thursday, November 20, 2014: 1:10 PM
210 (Hilton Atlanta)
Javen Weston1, Daniel E. Resasco1, Rolf E. Jentoft2, Jeff White3 and Jeffrey Harwell1, (1)School of Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, OK, (2)Chemical, Biological and Materials Engineering, University of Oklahoma, Norman, OK, (3)Oklahoma State University, Stillwater, OK


     The surface of colloidal silica nanoparticles is populated with hydroxyl groups that provide excellent anchoring sites for chemically-bonded surface modifiers. In particular, alkyl chlorosilanes can be used to hydrophobically modify silica surfaces, altering their wettability and increasing their ability to stabilize Pickering emulsions. This study seeks to investigate how particle wettability changes as a function of both fractional surface coverage and type of alkyl group. Fractional surface coverage was quantified using H NMR and particle wettability was quantified using three different methods: drop-shape analysis, the Washburn method for measuring powder wettability, and a calorimetric method using heat of immersion. The ability of these particles to stabilize Pickering emulsions and their location at the oil-water interface has also been probed using electron and light microscopy.

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See more of this Session: Functional Nanoparticles
See more of this Group/Topical: Particle Technology Forum