Article ID Journal Published Year Pages File Type
592536 Colloids and Surfaces A: Physicochemical and Engineering Aspects 2014 8 Pages PDF
Abstract

•Pickering emulsions are stabilized with phyllosilicates at high solid content.•Rheological measurements in steady state and oscillatory modes are compared.•Rheological properties of emulsions are strongly controlled by the initial suspension.•The rheological behavior depends on particle surface interactions and particle shape.•Halloysite leads to the highest rigidity, and palygorskite to the lowest.

The present study aims at investigating the preparation and characterization of oil-in-water (O/W) Pickering emulsions stabilized using three different phyllosilicates: kaolin, halloysite, and palygorskite, and at high solid content (15 wt.% in the aqueous phase). Stable O/W emulsions could be obtained with no additional surfactant or surface treatment. The maximal oil fraction that could be introduced without phase separation was determined. The resulting oil/water ratios of 0.32, 0.44 and 0.60 were found for kaolin, halloysite and palygorskite, respectively. The O/W character of the three emulsions was confirmed by a simple “droplet test” and by confocal microscopy, which confirmed the positioning of the clay particles at the oil/water interface. These three phyllosilicates led to a limited coalescence mechanism that promoted the long-term stability of the Pickering emulsions. The rheological behavior of these emulsions was studied and showed that halloysite led to a more rigid structure. This trend could be justified by the formation of a strong network of clay particles due to strong surface interactions combined with an elongated particle shape.

Graphical abstractFigure optionsDownload full-size imageDownload as PowerPoint slide

Related Topics
Physical Sciences and Engineering Chemical Engineering Colloid and Surface Chemistry
Authors
, , , , , ,