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Self-assembly of polyion-surfactant ion complex salts in mixtures with water and n-alcohols.

Bernardes JS, Piculell L, Loh W - J Phys Chem B (2011)

Bottom Line: The obtained results were compared with a previous work on similar ternary mixtures of the same cationic surfactant but with the monomeric bromide counterion, CTABr (Fontell, K.; Khan, A.; Lindström, B.; Maciejewska, D.; Puang-Ngern, S.Colloid Polym.For mixtures with octanol and ethanol, in particular, the extensions of the disordered isotropic phases were larger for the complex salt with the shorter polyacrylate ions.

View Article: PubMed Central - PubMed

Affiliation: Institute of Chemistry, Universidade Estadual de Campinas Campinas (UNICAMP), Caixa Postal 6154, Campinas, SP, Brazil.

No MeSH data available.


Related in: MedlinePlus

SAXS spectraof samples contained in region L2: (a) composition: 35wt % of ethanol, 17 wt % of water, and 48 wt % of C16TAPA30, and cell parameter = 28.5 Å; (b) composition: 55 wt% of ethanol, 15 wt % of water, and 30 wt % of CTAPA30 andcell parameter = 28.8 Å.
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fig5: SAXS spectraof samples contained in region L2: (a) composition: 35wt % of ethanol, 17 wt % of water, and 48 wt % of C16TAPA30, and cell parameter = 28.5 Å; (b) composition: 55 wt% of ethanol, 15 wt % of water, and 30 wt % of CTAPA30 andcell parameter = 28.8 Å.

Mentions: As more ethanol was added to the system, a narrow three-phase regioncontaining L1 + hexagonal liquid crystalline phase anda top viscous isotropic phase appeared for both systems. The latterviscous phase (L2) displayed optical birefringence whensheared between crossed polarizers. A SAXS spectrum of the L2 phase presents only a single correlation peak and is shown in Figure 5. According to our previous results for mixtureswith butanol, hexanol, and octanol,(17) theL2 phase is composed of reverse polyion–surfactantion aggregates, where a fraction of the surfactant counterions maybe dissociated from the central polyion, dissolved in the alcoholmedium. We conclude that at a certain critical content of ethanolthe hydrophobically associated normal surfactant aggregates, whichexist in the wide water-rich normal hexagonal phase of the phase diagram,dissolve into electrostatically stabilized reverse aggregates becauseof the lower cohesive energy of ethanol compared with water.


Self-assembly of polyion-surfactant ion complex salts in mixtures with water and n-alcohols.

Bernardes JS, Piculell L, Loh W - J Phys Chem B (2011)

SAXS spectraof samples contained in region L2: (a) composition: 35wt % of ethanol, 17 wt % of water, and 48 wt % of C16TAPA30, and cell parameter = 28.5 Å; (b) composition: 55 wt% of ethanol, 15 wt % of water, and 30 wt % of CTAPA30 andcell parameter = 28.8 Å.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3211389&req=5

fig5: SAXS spectraof samples contained in region L2: (a) composition: 35wt % of ethanol, 17 wt % of water, and 48 wt % of C16TAPA30, and cell parameter = 28.5 Å; (b) composition: 55 wt% of ethanol, 15 wt % of water, and 30 wt % of CTAPA30 andcell parameter = 28.8 Å.
Mentions: As more ethanol was added to the system, a narrow three-phase regioncontaining L1 + hexagonal liquid crystalline phase anda top viscous isotropic phase appeared for both systems. The latterviscous phase (L2) displayed optical birefringence whensheared between crossed polarizers. A SAXS spectrum of the L2 phase presents only a single correlation peak and is shown in Figure 5. According to our previous results for mixtureswith butanol, hexanol, and octanol,(17) theL2 phase is composed of reverse polyion–surfactantion aggregates, where a fraction of the surfactant counterions maybe dissociated from the central polyion, dissolved in the alcoholmedium. We conclude that at a certain critical content of ethanolthe hydrophobically associated normal surfactant aggregates, whichexist in the wide water-rich normal hexagonal phase of the phase diagram,dissolve into electrostatically stabilized reverse aggregates becauseof the lower cohesive energy of ethanol compared with water.

Bottom Line: The obtained results were compared with a previous work on similar ternary mixtures of the same cationic surfactant but with the monomeric bromide counterion, CTABr (Fontell, K.; Khan, A.; Lindström, B.; Maciejewska, D.; Puang-Ngern, S.Colloid Polym.For mixtures with octanol and ethanol, in particular, the extensions of the disordered isotropic phases were larger for the complex salt with the shorter polyacrylate ions.

View Article: PubMed Central - PubMed

Affiliation: Institute of Chemistry, Universidade Estadual de Campinas Campinas (UNICAMP), Caixa Postal 6154, Campinas, SP, Brazil.

No MeSH data available.


Related in: MedlinePlus