Evaporation of aqueous dispersed systems and concentrated emulsions formulated with non-ionic surfactants

• Published in: International journal of heat and mass transfer Vol. 69; pp. 117 - 128
• Main Authors: Gutiérrez, Gemma, Benito, José M., Coca, José, Pazos, Carmen
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01-02-2014
• Subjects: Droplets; Emulsions; Evaporation; Evaporation rate; Mathematical models; Micelles; Minerals; Niosomes; Non-ionic surfactants; O/W emulsions; Surfactants; Vacuum evaporation; W/O emulsions; O/W emulsions; Vacuum evaporation; Non-ionic surfactants; Micelles; W/O emulsions; Niosomes
• ISSN: 0017-9310; 1879-2189
• DOI: 10.1016/j.ijheatmasstransfer.2013.10.013

Vacuum evaporation of aqueous surfactant systems and concentrated oil-in-water (O/W) and water-in-oil (W/O) emulsions was studied as a function of the base oil (castor oil, heavy mineral oil and light mineral oil), and the kind of non-ionic surfactant (Tween and Span series) used in their formulation. Water evaporation rates were measured from aqueous surfactant solutions/dispersions (5% w/w surfactant), and O/W emulsions (5% w/w surfactant) in 1:1 water/oil weight ratio. Vacuum evaporation of W/O emulsions was also investigated, since a W/O emulsion is formed when the emulsion inversion point is surpassed during the evaporation of O/W emulsions. Surface tension, conductivity and particle/droplet size distribution were measured to characterize the formulated systems. Three simple models were tested to fit the evaporation rate data and their consistency depends on the system under consideration.