Phase behavior and preparation of mesoporous silica in aqueous mixtures of fluorinated surfactant and hydrophobic fluorinated polymer

Sharma, Suraj Chandra; Kunieda, H.; Esquena, Jordi; Rodríguez‐Abreu, Carlos

doi:10.1016/j.jcis.2006.01.040

Cited by 27 publications

(35 citation statements)

References 48 publications

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“…In the previous study the temperature induced micellar growth was reported but well below the clouding point and the structure of the micelles close to the cloud point could not be pictured out. Similarly, Sharma et al [32] (from our group) have studied the ternary phase behavior of the C 8 F 17 EO 10 /water/PFPE system and mentioned about the oil solubilization. However, they did not study about the micellar structure and the transition induced by the added fluorinated oil.…”

Section: Introductionmentioning

confidence: 91%

“…The ternary phase diagram gives a clear picture on the formation of microemulsion with about 28 wt% of the PFPE solubilized at the interior of the micelles at 45 wt% surfactant. However, in the dilute region, say at 5 wt% surfactant only about 1.5 wt% oil can be solubilized [32] so that formation of microemulsion cannot be confirmed. The SAXS measurements have shown that both the oils induced cylinder-to-sphere transition on the micellar structure.…”

Section: Effects Of Oils On the Micellar Structurementioning

confidence: 98%

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Small-angle X-ray scattering (SAXS) study on nonionic fluorinated micelles in aqueous system

Shrestha

Sharma

Sato

et al. 2007

Journal of Colloid and Interface Science

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We have investigated the self-organization structures of perfluoroalkyl sulfonamide ethoxylate, C(8)F(17)SO(2)N(C(3)H(7))(CH(2)CH(2)O)(10)H, a nonionic fluorinated surfactant in aqueous system by small-angle X-ray scattering (SAXS) technique. Structural modulation of the nonionic fluorinated micelle induced by temperature change, surfactant concentration, and the added fluorinated oils have been systematically studied. The SAXS data were analyzed by the indirect Fourier transformation (IFT), and the generalized indirect Fourier transformation (GIFT) depending on the volume fraction of the surfactant. Various plausible classical model calculations have been performed to confirm the consistency of the GIFT analysis of the SAXS data. Upon successive increase in temperature, the cylindrical micelles formed at lower temperatures undergo a continuous one-dimensional growth and ultimately near the cloud point an indication of flat planar like structural pattern is observed. The evolution in structure of particle near the demixing temperature may be due to onset of attractive interactions. The shape and size of the micelle is apparently unaffected by changing the surfactant concentration from 1 to 5 wt% at 25 degrees C. Nevertheless, addition of small amount of perfluoropolyether (PFPE) oil, of structure F(CF(2)CF(2)CF(2)O)(n)CF(2)CF(2)COOH (n approximately 21) modulate the micellar shape and size. Long cylindrical micelles eventually transform into globular like particles. The onset cylinder-to-sphere transition in the structure of micelles in the surfactant/water/oil system is probably due to amphiphilic nature of the oil, which tends to increase the spontaneous curvature. The lipophilic part of the oil tends to reside in the micellar core, whereas, the hydrophilic part goes close to the polar head group of the surfactant so that effective cross-sectional area per surfactant molecules increases and as a result spherical micelles tend to form. Perfluorodecalin (PFD) also decreases size of the micelles but its effect is poor compared to the PFPE oil.

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Section: Introductionmentioning

confidence: 91%

Section: Effects Of Oils On the Micellar Structurementioning

confidence: 98%

Small-angle X-ray scattering (SAXS) study on nonionic fluorinated micelles in aqueous system

Shrestha

Sharma

Sato

et al. 2007

Journal of Colloid and Interface Science

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“…Reverse micelles stabilize reactive species that is insoluble in nonpolar solvents, and is also used as a size controlling micro-reactor for different aqueous chemical reactions 1,2 . Reverse micelles have been used as template for the synthesis of nanomaterials for a long time [3][4][5][6][7][8][9] . It has been found that the structure of the nanomaterials largely depends on the structure size and shape of the template micelles 10 .…”

Section: Introductionmentioning

confidence: 99%

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

Shrestha

Oyama

et al. 2010

J. Oleo Sci.

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Using a small-angle X-ray scattering technique, shape and size, and internal structure of diglycerol polyisostearate nonionic surfactant micelles in nonpolar oil n-hexadecane (HD) were investigated at 25 . Furthermore, the effect of added water on the structure of host reverse micelles was also investigated. The scattering data were evaluated by the generalized indirect Fourier transformation (GIFT) method and model fi ttings. It was found that diglycerol polyisostearate (abbreviated as (iso-C 18 ) n G 2 , where n = 2-4 represent the number of isostearate chain per surfactant molecule) spontaneously form reverse micelles in HD at 25 and their geometry (shape and size, and internal structure) could fl exibly be controlled by a small change in the lipophilic tail architecture of the surfactant, temperature, and water addition. Increasing number of isostearate chain per surfactant molecule decreases the micelles size favoring prolate-to-sphere type transition. This phenomenon could be best understood due to voluminous lipophilic part of the surfactant. Increasing temperature decreases the size of the reverse micelles due to enhanced interpenetration of the surfactant chain and the oil and also due to dominant hydrophobic character of the surfactant at higher temperatures. In the studies of effect of added water on the structure of micelles, it was found that the reverse micelles swell with water causing two dimensional micellar growths.

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“…Moreover, they form aggregates at lower concentrations [5] and have high chemical and thermal stability [6]. Fluorocarbon surfactants have been used as structure directors for the synthesis of mesoporous silica [7][8][9][10] and also for the formation of ordered composites through complexation with polyelectrolytes [11]. The functionalization of silica with fluorocarbon chains offers possibilities for applications such as protective coatings [12] and low dielectric constant materials for semiconductors [13].…”

Section: Introductionmentioning

confidence: 99%

Structure and properties of self-assembled fluorocarbon–silica nanocomposites

Rodríguez‐Abreu

Botta

Rivas

et al. 2008

Journal of Non-Crystalline Solids

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Phase behavior and preparation of mesoporous silica in aqueous mixtures of fluorinated surfactant and hydrophobic fluorinated polymer

Cited by 27 publications

References 48 publications

Small-angle X-ray scattering (SAXS) study on nonionic fluorinated micelles in aqueous system

Small-angle X-ray scattering (SAXS) study on nonionic fluorinated micelles in aqueous system

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

Structure and properties of self-assembled fluorocarbon–silica nanocomposites

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