Phase inversion emulsification: Current understanding and applications

• Published in: Advances in colloid and interface science Vol. 222; pp. 581 - 599
• Main Authors: Perazzo, A., Preziosi, V., Guido, S.
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.08.2015
• Subjects: Colloidal particles; Drug-delivery; Emulsion phase inversion; Emulsions - chemistry; Humans; Nanoemulsions; Oil recovery; Phase behavior; Phase Transition; Emulsion phase inversion; Nanoemulsions; Drug-delivery; Colloidal particles; Oil recovery; Phase behavior
• ISSN: 0001-8686; 1873-3727; 1873-3727
• DOI: 10.1016/j.cis.2015.01.001

This review is addressed to the phase inversion process, which is not only a common, low-energy route to make stable emulsions for a variety of industrial products spanning from food to pharmaceuticals, but can also be an undesired effect in some applications, such as crude oil transportation in pipelines. Two main ways to induce phase inversion are described in the literature, i.e., phase inversion composition (PIC or catastrophic) and phase inversion temperature (PIT or transitional). In the former, starting from one phase (oil or water) with surfactants, the other phase is more or less gradually added until it reverts to the continuous phase. In PIT, phase inversion is driven by a temperature change without varying system composition. Given its industrial relevance and scientific challenge, phase inversion has been the subject of a number of papers in the literature, including extensive reviews. Due to the variety of applications and the complexity of the problem, most of the publications have been focused either on the phase behavior or the interfacial properties or the mixing process of the two phases. Although all these aspects are quite important in studying phase inversion and much progress has been done on this topic, a comprehensive picture is still lacking. In particular, the general mechanisms governing the inversion phenomenon have not been completely elucidated and quantitative predictions of the phase inversion point are limited to specific systems and experimental conditions. Here, we review the different approaches on phase inversion and highlight some related applications, including future and emerging perspectives. Possible phase inversion emulsification pathways showed in phase diagram A) and emulsification map B). C) Evidence of multiple emulsion formation prior to phase inversion. D) Example of clathrate hydrate formation. A) Colloids and Surfaces A, Volume399, pages 25–34, 2012 B) Colloids and Surfaces A, Volume 288, pages 151–157 Issue 1–3, 2006 C) Advanced Materials Volume 25 (2013) pages 2844–2848, 2013 D) Chemical Engineering Science, Volume 63, pages 4570–4579, 2008 [Display omitted] •Phase inversion is an important industrial process to make stable emulsions.•Phase inversion can be driven by composition or temperature changes.•Phase behavior or interfacial properties or mixing of the phases has been studied.•A comprehensive picture of phase inversion is still lacking.•Here, we review the different approaches and highlight some related applications.