Modification of interfacial characteristics of monodisperse droplets produced using membrane emulsification by surfactant displacement and/or polyelectrolyte electrostatic deposition

Abstract

This study examined the possibility of modifying the interfacial characteristics of uniformly sized droplets produced by premix membrane emulsification using surfactant-displacement and/or electrostatic deposition methods. The non-ionic surfactant Tween 20 is particularly effective at producing uniformly sized lipid droplets by premix membrane emulsification, but the droplets produced have a low net charge. The interfacial characteristics of emulsion droplets initially coated by Tween 20 could be made either negative or positive (without altering droplet size) by adding controlled amounts of either anionic emulsifiers (SDS) or cationic emulsifiers (DTAB or beta-lactoglobulin) to the continuous phase after homogenisation. In addition, cationic emulsion droplets could be prepared by depositing a cationic biopolymer (chitosan) onto the surfaces of anionic droplets (SDS/Tween coated). These results have important consequences for the design, fabrication and utilisation of uniformly sized lipid droplets with controlled interfacial characteristics. (C) 2010 Elsevier B.V. All rights reserved.