Structure of Diglycerol Polyisostearate Nonionic Surfactant Micelles in Nonpolar Oil Hexadecane: A SAXS Study

Shrestha, Lok Kumar; Shrestha, Rekha Goswami; Oyama, Keiichi; Matsuzawa, Makoto; Aramaki, Kenji

doi:10.5650/jos.59.339

Cited by 13 publications

(20 citation statements)

References 49 publications

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“…Reverse micelles was possible to formulate under ambient conditions with the long and branched chain surfactants. [38][39][40] Recent formulation of the charge free reverse wormlike micelles (entangled networks of flexible cylindrical micelles) without water addition in sucrose-based nonionic surfactant systems has opened a new direction in the fundamental research of surfactant self-assemblies in nonaqueous media. 41 Otherwise the reverse wormlike micelle was only possible to achieve with ionic surfactants in which water and/or salts are fundamentally required to induce micellar growth so far.…”

Section: Introductionmentioning

confidence: 99%

Reverse Micelle Microstructural Transformations Induced by Surfactant Molecular Structure, Concentration, and Temperature

Shrestha

Ariga

et al. 2011

J. Nanosci. Nanotech.

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We have investigated the microstructural transformations of nonionic surfactant reverse micelles induced by surfactant molecular architecture, surfactant concentration, and temperature in nonaqueous media. The investigations were based on small-angle X-ray scattering (SAXS) and rheometry techniques. Polyglycerol polyoleic acid esters spontaneously self-assembled into reverse micelle in n-decane under ambient conditions, whose shape, size, and internal structure could be controlled by the surfactant molecular architecture, concentration, and temperature. The maximum size of the micelles was found to increase with an increase in the hydrophilic headgroup size of the surfactant. On the other hand, an opposite trend was observed with an increase in the number of oleate chain per surfactant molecules, which was well supported by rheology data; viscosity decreased with the number of oleate chain per surfactant molecule. The SAXS and rheology data have shown a clear evidence of one dimensional micellar growth with increase in the surfactant concentration. The relative viscosity, eta(r), of the reverse micelle exhibited steeper concentration dependence behavior than those predicted for a dispersion of spherical particles based on the Krieger-Dougherty relation which provided a clear evidence of the presence of elongated micelles at higher concentration. An ellipsoidal prolate-to-sphere type transition was observed upon heating.

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Section: Introductionmentioning

confidence: 99%

Reverse Micelle Microstructural Transformations Induced by Surfactant Molecular Structure, Concentration, and Temperature

Shrestha

Ariga

et al. 2011

J. Nanosci. Nanotech.

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“…Indirect Fourier Transformation (IFT) of an aqueous solution of Pd-MS (10 mM) was carried out according to reference procedures. [8][9][10]…”

Section: Small Angle X-ray Scattering (Saxs)mentioning

confidence: 99%

Au(i)-, Ag(i)-, and Pd(ii)-coordination-driven diverse self-assembly of an N-heterocyclic carbene-based amphiphile

et al. 2021

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“…In our previous investigations we have found that polyglycerol fatty acid esters, being more solvophobic compared to the ethylene oxide (EO)-based conventional nonionic surfactants, self-assemble into a variety of structures in surfactant/oil binary systems. [45][46][47][48] Short chain mono-and diglycerol fatty acid esters, when mixed with linear chain or aliphatic alkanes, formed solid or lamellar liquid crystal phase at room temperature. 44 49 Reverse micelles were possible to form only at higher temperatures after melting of these solid or lamellar liquid crystal phases.…”

Section: Introductionmentioning

confidence: 99%

Structural Characterizations of Diglycerol Monomyristate Reverse Micelles in Aromatic Solvent Ethylbenzene

Shrestha¹,

Shrestha²,

Aramaki³

et al. 2012

j. nanosci. nanotech.

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Using small-angle X-ray scattering (SAXS) we have investigated the shape and size of diglycerol monomyristate (designated as C14G2) nonionic surfactant reverse micelles in aromatic solvent ethylbenzene as a function of surfactant concentration, temperature, and water. When C14G2 is added into ethylbenzene globular type reverse micelles with maximum core diameter ca. 4.5 nm are formed under ambient conditions. The micellar structure (shape and size) did not change with the surfactant concentration. However, an increase in temperature decreased the micellar size due to an increase in the critical packing parameter (cpp). Surfactant becomes more lipophilic upon heating and the micellar curvature tends to become more negative at higher temperature. Addition of a small amount of water caused a significant micellar growth. For instance, incorporation of 0.3% water in the 5% C14G2/ethylbenzene system resulted in the formation of 2.1 time bigger micelles with a small water pool in the micellar core. Besides the micellar shape is modified into an ellipsoidal prolate, whose scenario can be understood in terms of hydration of the surfactant's headgroup. Hydration decreases the cpp and favors micellar growth. An increase of temperature of a water incorporated system decreased the micellar size due to dehydration, which is equivalent to rod-to-sphere type transition.

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Structure of Diglycerol Polyisostearate Nonionic Surfactant Micelles in Nonpolar Oil Hexadecane: A SAXS Study

Cited by 13 publications

References 49 publications

Reverse Micelle Microstructural Transformations Induced by Surfactant Molecular Structure, Concentration, and Temperature

Reverse Micelle Microstructural Transformations Induced by Surfactant Molecular Structure, Concentration, and Temperature

Au(i)-, Ag(i)-, and Pd(ii)-coordination-driven diverse self-assembly of an N-heterocyclic carbene-based amphiphile

Structural Characterizations of Diglycerol Monomyristate Reverse Micelles in Aromatic Solvent Ethylbenzene

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