Curvature as a determinant of microstructure and microemulsions

a b s t r a c tHofmeister, specific ion effects, hydration and van der Waals forces at and between interfaces are factors that determine curvature and microstructure in self assembled aggregates of surfactants and lipids; and in microemulsions. Lipid and surfactant head group interactions and between aggregates vary enormously and are highly specific. They act on the hydrophilic side of a bilayer, micelle or other self assembled aggregate. It is only over the last three decades that the origin of Hofmeister effects has become generally understood. Knowledge of their systematics now provides much flexibility in designing nanostructured fluids.The other side of the coin involves equally specific forces. These (opposing) forces work on the hydrophobic side of amphiphilic interfaces. They are due to the interaction of hydrocarbons and other "oils" with hydrophobic tails of surfactants and lipids. The specificity of oleophilic solutes in microemulsions and lipid membranes provides a counterpoint to Hofmeister effects and hydration. Together with global packing constraints these effects determine microstructure.Another factor that has hardly been recognised is the role of dissolved gas. This introduces further, qualitative changes in forces that prescribe microstructure.The systematics of these effects and their interplay are elucidated. Awareness of these competing factors facilitates formulation of self assembled nanostructured fluids. New and predictable geometries that emerge naturally provide insights into a variety of biological phenomena like anaesthetic and pheromone action and transmission of the nervous impulse (see Part 2).

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“…The system is mostly bicontinuous across the large one phase region, a random bicontinuous connected network as depicted in Fig. 11 [80,81].…”

Section: Phase Diagrams In Ternary Microemulsionsmentioning

confidence: 99%

Two sides of the coin. Part 1. Lipid and surfactant self-assembly revisited

Ninham

Larsson

Nostro

2017

Colloids and Surfaces B: Biointerfaces

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“…Ionic double-chain surfactants, such as AOT and didodecyldimethylammonium bromide (DDAB) constitute an important class of surfactants and can form three-component microemulsions. 101,102,103,104,105 The major theoretical requirement for the existence of a three-component microemulsion system is that the packing parameter is close to 1. 106 For most of these double-chain surfactants, this condition is fulfilled.…”

Section: Microemulsions With Ionic Surfactantsmentioning

confidence: 99%

Ionic Liquids in Microemulsions—A Concept To Extend the Conventional Thermal Stability Range of Microemulsions

Zech¹,

Thomaier²,

Kolodziejski³

et al. 2010

Chemistry A European J

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“…uctivity. In some systems, a sharp variation in its dielectric behavior and in its viscosity, as the temperature reaches a limit, is also observed [5]. The oil-watermicroemulsion coexisting region exhibits also an ultralow surface tension betw'een those phases [6].…”

Section: Intrgductionmentioning

confidence: 99%

Microemulsion model with oil-water anisotropy

Barbosa

Frichembruder

1995

Phys. Rev. E

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We consider a spin model for applications to oil-water -amphiphilic-surfactant mixtures near the region where those phases coexist. We analyze this model assuming that oil and water molecules cannot be treated symmetrically, given that they do exhibit different chemical potentials. Using a mean-field approximation, we find that the modulated phase assumes two possible arrangements, such as sheets (lamellar phase) or rods (hexagonal phase). Due to fluctuations, the lamellar phase is present when the difference between the chemical potential of oil

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Curvature as a determinant of microstructure and microemulsions

Cited by 163 publications

References 2 publications

Two sides of the coin. Part 1. Lipid and surfactant self-assembly revisited

Two sides of the coin. Part 1. Lipid and surfactant self-assembly revisited

Ionic Liquids in Microemulsions—A Concept To Extend the Conventional Thermal Stability Range of Microemulsions

Microemulsion model with oil-water anisotropy

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