Phase inversion in nonionic surfactant-oil-water systems

This study has been concerned with the inversion of water in oil (W/0) emulsions, to oil in water (O/W) emulsions and vice-versa. It has been shown that there are two types of emulsion phase inversion that can occur in nonionic Surfactant-Oil-Water (nSOW) systems: (i) A "transitional" inve...

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Main Author: Howard N. Richmond
Format: Default Thesis
Published: 1992
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Online Access:https://hdl.handle.net/2134/14713
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spelling rr-article-92379681992-01-01T00:00:00Z Phase inversion in nonionic surfactant-oil-water systems Howard N. Richmond (7127273) Chemical engineering not elsewhere classified untagged Chemical Engineering not elsewhere classified This study has been concerned with the inversion of water in oil (W/0) emulsions, to oil in water (O/W) emulsions and vice-versa. It has been shown that there are two types of emulsion phase inversion that can occur in nonionic Surfactant-Oil-Water (nSOW) systems: (i) A "transitional" inversion, which is brought about by changing the nSOW phase behaviour, by altering the surfactant's affinity for the oil and water phases and, (ii) a "catastrophic" inversion, induced by increasing the dispersed phase fraction and occurs at closest packing of unstable dispersed phase drops. The inversion mechanism of the two inversion types has been characterised. The two inversion types can be represented as boundaries on a "map" relating nSOW phase behaviour with water to oil volume ratio. The form of the map depends on the nature of the oil. At the transitional point, the nSOW system can be 3 phase - an oil phase, a water phase and a surfactant phase microemulsion. Ultra-low interfacial tension exists between the phases - this property is of interest for producing extremely fine emulsions with low energy input. Transitional inversions are sometimes reversible. In nSOW systems, true catastrophic inversions can be induced by moving the water to oil ratio in one direction only. Double emulsion drops (W/O/W or O/W/O) are sometimes produced before inversion and inversion points are dependent on dynamic conditions. A thermodynamic relationship between nSOW phase behaviour, oil type, surfactant type, surfactant concentration and temperature has been derived, based on the partitioning of surfactant between oil, water and a surfactant micelle phase. It has been shown how this can be used to classify nonionic surfactants. The effect of agitation conditions, water addition rate and oil phase viscosity, on the drop types and drop sizes of emulsions present before and after inversion (for each inversion type) has been studied extensively. Surfactant type and concentration also affect drop behaviour and drop sizes. Various drop types have been identified and qualitative and quantitative analysis of the factors controlling the drop sizes of emulsions at each stage of a phase inversion has been developed. 1992-01-01T00:00:00Z Text Thesis 2134/14713 https://figshare.com/articles/thesis/Phase_inversion_in_nonionic_surfactant-oil-water_systems/9237968 CC BY-NC-ND 4.0
institution Loughborough University
collection Figshare
topic Chemical engineering not elsewhere classified
untagged
Chemical Engineering not elsewhere classified
spellingShingle Chemical engineering not elsewhere classified
untagged
Chemical Engineering not elsewhere classified
Howard N. Richmond
Phase inversion in nonionic surfactant-oil-water systems
description This study has been concerned with the inversion of water in oil (W/0) emulsions, to oil in water (O/W) emulsions and vice-versa. It has been shown that there are two types of emulsion phase inversion that can occur in nonionic Surfactant-Oil-Water (nSOW) systems: (i) A "transitional" inversion, which is brought about by changing the nSOW phase behaviour, by altering the surfactant's affinity for the oil and water phases and, (ii) a "catastrophic" inversion, induced by increasing the dispersed phase fraction and occurs at closest packing of unstable dispersed phase drops. The inversion mechanism of the two inversion types has been characterised. The two inversion types can be represented as boundaries on a "map" relating nSOW phase behaviour with water to oil volume ratio. The form of the map depends on the nature of the oil. At the transitional point, the nSOW system can be 3 phase - an oil phase, a water phase and a surfactant phase microemulsion. Ultra-low interfacial tension exists between the phases - this property is of interest for producing extremely fine emulsions with low energy input. Transitional inversions are sometimes reversible. In nSOW systems, true catastrophic inversions can be induced by moving the water to oil ratio in one direction only. Double emulsion drops (W/O/W or O/W/O) are sometimes produced before inversion and inversion points are dependent on dynamic conditions. A thermodynamic relationship between nSOW phase behaviour, oil type, surfactant type, surfactant concentration and temperature has been derived, based on the partitioning of surfactant between oil, water and a surfactant micelle phase. It has been shown how this can be used to classify nonionic surfactants. The effect of agitation conditions, water addition rate and oil phase viscosity, on the drop types and drop sizes of emulsions present before and after inversion (for each inversion type) has been studied extensively. Surfactant type and concentration also affect drop behaviour and drop sizes. Various drop types have been identified and qualitative and quantitative analysis of the factors controlling the drop sizes of emulsions at each stage of a phase inversion has been developed.
format Default
Thesis
author Howard N. Richmond
author_facet Howard N. Richmond
author_sort Howard N. Richmond (7127273)
title Phase inversion in nonionic surfactant-oil-water systems
title_short Phase inversion in nonionic surfactant-oil-water systems
title_full Phase inversion in nonionic surfactant-oil-water systems
title_fullStr Phase inversion in nonionic surfactant-oil-water systems
title_full_unstemmed Phase inversion in nonionic surfactant-oil-water systems
title_sort phase inversion in nonionic surfactant-oil-water systems
publishDate 1992
url https://hdl.handle.net/2134/14713
_version_ 1800366377194749952