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Probing competitive interactions in quaternary formulations.

Journal of colloid and interface science (2015-05-24)
Omar T Mansour, Beatrice Cattoz, Richard K Heenan, Stephen M King, Peter C Griffiths
ABSTRACT

The interaction of amphiphilic block copolymers of the poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) group with small molecule surfactants may be "tuned" by the presence of selected alcohols, with strong interactions leading to substantial changes in (mixed) micelle morphology, whilst weaker interactions lead to coexisting micelle types. The nature and the strength of the interactions between Pluronic P123 (EO20PO70EO20) and small molecule surfactants (anionic sodium dodecylsulfate, SDS, C12SO4Na), (cationic dodecyltrimethylammonium bromide, C12TAB) and (non-ionic polyoxyethylene(23)lauryl ether, Brij 35, C12EO23OH) is expected to depend on the partitioning of the short, medium and long chain alcohols (ethanol, hexanol and decanol respectively) and was probed using tensiometry, pulsed-gradient spin-echo nuclear magnetic resonance (PGSE-NMR) and small-angle neutron scattering (SANS). The SANS data for aqueous P123 solutions with added alcohols were well described by a charged spherical core/shell model for the micelle morphology. The addition of the surfactants led to significantly smaller, oblate elliptical mixed micelles in the absence of alcohols. Addition of ethanol to these systems led to a decrease in the micelle size, whereas larger micelles were observed upon addition of the longer chain alcohols. NMR studies provided complementary estimates of the micelle composition, and the partitioning of the various components into the micelle.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
1-Decanol, ≥98%, FCC, FG
Sigma-Aldrich
Deuterium oxide, standard, 99.98 atom %±0.01 atom % D
Sigma-Aldrich
Deuterium oxide, 99.9 atom % D, contains 0.05 wt. % 3-(trimethylsilyl)propionic-2,2,3,3-d4 acid, sodium salt
Sigma-Aldrich
Deuterium oxide, 99.9 atom % D, contains 1 % (w/w) 3-(trimethylsilyl)-1-propanesulfonic acid, sodium salt (DSS)
Sigma-Aldrich
Hexyl alcohol, FCC, FG
Sigma-Aldrich
Hexyl alcohol, natural, ≥98%, FCC, FG
Sigma-Aldrich
Ethyl alcohol, Pure, 190 proof, meets USP testing specifications
Sigma-Aldrich
Deuterium oxide, "100%", 99.990 atom % D
Sigma-Aldrich
Ethyl alcohol, Pure, 190 proof, ACS spectrophotometric grade, 95.0%
Sigma-Aldrich
Deuterium oxide, "100%", ≥99.96 atom % D
Sigma-Aldrich
Deuterium oxide, 99.9 atom % D
Sigma-Aldrich
Deuterium oxide, 99.9 atom % D, contains 0.75 wt. % 3-(trimethylsilyl)propionic-2,2,3,3-d4 acid, sodium salt
Sigma-Aldrich
1-Hexanol, anhydrous, ≥99%
Sigma-Aldrich
1-Hexanol, ReagentPlus®, ≥99.5% (GC)
Sigma-Aldrich
Sodium dodecyl sulfate solution, BioUltra, for molecular biology, 20% in H2O
Sigma-Aldrich
Sodium dodecyl sulfate solution, BioUltra, for molecular biology, 10% in H2O
Sigma-Aldrich
1-Decanol, ≥98%
Sigma-Aldrich
Deuterium oxide, extra, 99.994 atom % D
Sigma-Aldrich
Deuterium oxide, 99.9 atom % D, glass distilled
Sigma-Aldrich
Deuterium oxide, 99 atom % D
Sigma-Aldrich
1-Decanol, 98%
Sigma-Aldrich
Deuterium oxide, 99.8 atom % D
Sigma-Aldrich
Ethyl alcohol, Pure, 200 proof, anhydrous, ≥99.5%
Sigma-Aldrich
Deuterium oxide, filtered, 99.8 atom % D
Sigma-Aldrich
Deuterium oxide, 60 atom % D
Sigma-Aldrich
Deuterium oxide, 70 atom % D
Sigma-Aldrich
Sodium dodecyl sulfate, BioReagent, suitable for electrophoresis, for molecular biology, ≥98.5% (GC)
Sigma-Aldrich
Dodecyltrimethylammonium bromide, BioXtra, ~99%
Sigma-Aldrich
Dodecyltrimethylammonium bromide, ≥98%
Sigma-Aldrich
Sodium dodecyl sulfate, 92.5-100.5% based on total alkyl sulfate content basis