Microemulsions

Hloucha, Matthias

doi:10.1002/14356007.q16_q02

Cited by 4 publications

(2 citation statements)

References 135 publications

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“…The emulsions formed by 2-hexyldecanoic and MEEA NPs are shown as a model compound in Figure 5a,b, respectively. As can be seem from the Figure 5a, around 5 min after emulsification, one-phase emulsions (type IV) 43 were formed for 10–50% water addition and two phases (with excess water, type II) were observed for 75–90% water. After 1 day the one-phase emulsions were changed to two phase (with excess oil, type I); however, the emulsion fractions were still significant beyond 1 day (e.g., 0.6 for 90:10 and 0.9 for 50:50 oil–water ratios).…”

Section: Resultsmentioning

confidence: 77%

Tunable Surface Properties of Aluminum Oxide Nanoparticles from Highly Hydrophobic to Highly Hydrophilic

et al. 2017

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The formation of materials with tunable wettability is important for applications ranging from antifouling to waterproofing surfaces. We report the use of various low-cost and nonhazardous hydrocarbon materials to tune the surface properties of aluminum oxide nanoparticles (NPs) from superhydrophilic to superhydrophobic through covalent functionalization. The hydrocarbon surfaces are compared with a fluorinated surface for wettability and surface energy properties. The role of NPs’ hydrophobicity on their dynamic interfacial behavior at the oil–water interface and their ability to form stable emulsions is also explored. The spray-coated NPs provide textured surfaces (regardless of functionality), with water contact angles (θ) of 10–150° based on their surface functionality. The superhydrophobic NPs are able to reduce the interfacial tension of various oil–water interfaces by behaving as surfactants.

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Section: Resultsmentioning

confidence: 77%

Tunable Surface Properties of Aluminum Oxide Nanoparticles from Highly Hydrophobic to Highly Hydrophilic

et al. 2017

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“…However, it should be noted that such corrections by appropriate formulation will not always allow large microemulsion domains required for applications as, for instance, seen in the case of APG that requires high amounts of cosurfactant (e.g., glycerolmonooleate) and still only forms a narrow microemulsions channel, not adapted for efficient solubilization of active solutes . Quite generally it is observed that best the length of the alkyl chain of the cosurfactant is a bit less than half that of the surfactant, as for instance given for SDS/1-pentanol, while longer chain alcohols like 1-hexanol or 1-heptanol lead to too stiff monolayers .…”

Section: Microemulsions: Entropy Versus Film Packingmentioning

confidence: 99%

Using Microemulsions: Formulation Based on Knowledge of Their Mesostructure

et al. 2021

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Microemulsions, as thermodynamically stable mixtures of oil, water, and surfactant, are known and have been studied for more than 70 years. However, even today there are still quite a number of unclear aspects, and more recent research work has modified and extended our picture. This review gives a short overview of how the understanding of microemulsions has developed, the current view on their properties and structural features, and in particular, how they are related to applications. We also discuss more recent developments regarding nonclassical microemulsions such as surfactant-free (ultraflexible) microemulsions or ones containing uncommon solvents or amphiphiles (like antagonistic salts). These new findings challenge to some extent our previous understanding of microemulsions, which therefore has to be extended to look at the different types of microemulsions in a unified way. In particular, the flexibility of the amphiphilic film is the key property to classify different microemulsion types and their properties in this review. Such a classification of microemulsions requires a thorough determination of their structural properties, and therefore, the experimental methods to determine microemulsion structure and dynamics are reviewed briefly, with a particular emphasis on recent developments in the field of direct imaging by means of electron microscopy. Based on this classification of microemulsions, we then discuss their applications, where the application demands have to be met by the properties of the microemulsion, which in turn are controlled by the flexibility of their amphiphilic interface. Another frequently important aspect for applications is the control of the rheological properties. Normally, microemulsions are low viscous and therefore enhancing viscosity has to be achieved by either having high concentrations (often not wished for) or additives, which do not significantly interfere with the microemulsion. Accordingly, this review gives a comprehensive account of the properties of microemulsions, including most recent developments and bringing them together from a united viewpoint, with an emphasis on how this affects the way of formulating microemulsions for a given application with desired properties.

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