Marius Rutkevičius
| PhD, Physical Chemistry 2014 University of Hull, UK B.S., Chemistry with Medicinal Chemistry 2010 University of Warwick, UK |  |
Research Focus: Emulsion stabilization with environmentally benign particles of sustainable origin
Solid particles adsorb at fluid-fluid (e.g., oil-water) interfaces and thus stabilize emulsions. Such emulsions are called Pickering emulsions. Due to their potential to eliminate conventional surfactants Pickering emulsions attract industrial interest. Solid particles, such as ethyl cellulose, silica, calcium carbonate, fat crystals and others have recently been shown to stabilize these fluid-in-fluid dispersions. The introduction of new benign nanoparticle production techniques allows a much broader range of sustainable materials to be used for the production of nanoparticles for the use in Pickering emulsions. We are developing insoluble plant protein particles for oil-continuous emulsion stabilization. These proteins have nearly equal proportion of hydrophilic and hydrophobic amino acids, making them insoluble in water or ethanol, but soluble in ethanol-water mixtures. We precipitate protein particles at the oil-water interface by lowering the quality of the solvent (antisolvent precipitation method). We study the ability of the protein to stabilize high water content oil-continuous emulsions, the influence of protein concentration and salt content, as well as influence of pH to develop stable emulsions. The analyses and interpretations of the interactions of the particles and the interfaces enable us to establish fundamental origin of stabilization and compare our particles with synthetic alternatives reported in literature.
Figure 1. Fluorescence microscopy images of water-in-oil emulsion (left) and oil-in-water emulsion (middle) stabilized with solid plant protein particles. The former is formed when pH is set to 4 and the latter is produced at pH 8, which results in a different charge of the protein, which could be causing the phase inversion. Confocal microscopy image (right) showing a layer or protein (in green) adsorbed at the oil-water interface at pH 8. Water is colored in black and oil is in yellow. In all images oil phase was stained with Nile Red dye and water with Nile Blue dye.