Hydrophilic and hydrophobic modifications of colloidal silica particles for Pickering emulsions
Journal article, 2017

Colloidal silica particles, functionalized with hydrophilic and hydrophobic groups, have been studied for utilization in particle-stabilized emulsions, so called Pickering emulsions. The amounts of attached groups have been characterized using NMR spectroscopy and elemental analysis. A range of particles were prepared, with sizes from around 13 to 70 nm in diameter. Hydrophilic functionalization of the silica sols was achieved by attaching methyl poly(ethylene glycol) (mPEG) silane to the silica particle surface. This provides a reduction of surface charge density, a pH dependent and controllable flocculation behavior and surface activity. The hydrophobic functionalization of the silica sols was accomplished by attaching organosilanes containing mainly propyl and methyl groups. The emulsification abilities were evaluated by preparing Pickering emulsions using particles, with varying degrees and combinations of surface functionalization, as stabilizers and comparing the obtained emulsion droplet size distributions. It was found that colloidal silica functionalized with hydrophobic groups produced emulsions with smaller droplets compared to using unmodified silica. The emulsification performance was further improved by the combination of both hydrophilic and hydrophobic groups. All particles having this heterogeneous modification were found to generate emulsions with high stability towards coalescence (from five weeks to 1.5 years).

Functionalized colloidal silica

Controlled flocculation

mbe de

stabilized emulsions

land

v343

p70

oil

Pickering emulsions

v52

latex-particles

advances in colloid and interface science

nanoparticles

Chemistry

p1

1994

Author

Sanna Björkegren

Chalmers, Chemistry and Chemical Engineering

Lars Nordstierna

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Applied Surface Chemistry

A. Torncrona

Akzo Nobel Surface Chemistry AB

Anders Palmqvist

Chalmers, Chemistry and Chemical Engineering, Applied Chemistry, Applied Surface Chemistry

Journal of Colloid and Interface Science

0021-9797 (ISSN)

Vol. 487 250-257

Subject Categories

Physical Chemistry

DOI

10.1016/j.jcis.2016.10.031

More information

Created

10/7/2017