Microwave-field-assisted enhanced demixing of aqueous two-phase systems

The slow rate of demixing is a major limitation in wide commercial exploitation of aqueous two-phase systems. In the present work, use of a microwave field has been explored for the first time to enhance phase demixing rates (decrease demixing times) of these systems. The microwave-field-assisted demixing process decreased the demixing time by about 2- to 4-fold in a polyethylene glycol/potassium phosphate system and by about 1.5- to 6.5-fold in a polyethylene glycol/maltodextrin system. The enhanced demixing rate can be explained by the dipole rotation, electrophoretic migration of free salts, multiple reflections at the interfaces, droplet-droplet collision, and reduced viscosity of the continuous phase that occur during the application of a microwave field. (C) 2003 Elsevier Science (USA). All rights reserved.