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Aqueous Binary Mixtures of Stearic Acid and Its Hydroxylated Counterpart 12-Hydroxystearic Acid: Cascade of Morphological Transitions at Room Temperature
被引:4
|作者:
Almeida, Maëva
[1
,2
]
Dudzinski, Daniel
[2
]
Amiel, Catherine
[1
]
Guigner, Jean-Michel
[3
,4
]
Prevost, Sylvain
[5
]
Le Coeur, Clemence
[1
,2
]
Cousin, Fabrice
[1
]
机构:
[1] Univ Paris Est Creteil, Inst Chim & Mat Paris Est, CNRS, UMR 7182, 2 Rue Henri Dunant, F-94320 Thiais, France
[2] Univ Paris Saclay, Lab Leon Brillouin, CEA, CNRS,UMR 12,CEA Saclay, F-91191 Saclay, France
[3] Sorbonne Univ, Inst Mineral Phys Mat & Cosmochim IMPMC, IRD, CNRS,MNHN, CEDEX 05, F-75252 Paris, France
[4] CNRS, UMR 7590, F-75252 Paris 05, France
[5] Inst Laue Langevin, 71 Ave Martyrs,CS 20156, F-38042 Grenoble 9, France
来源:
关键词:
hydroxystearic acid;
stearic acid;
self-assembly;
mixtures;
small angle neutron scattering;
FATTY-ACIDS;
CARBOXYLATE SURFACTANTS;
LANGMUIR MONOLAYERS;
SELF-ASSEMBLIES;
MOLECULAR GELS;
PHASE-BEHAVIOR;
LIPID TUBES;
MOLAR RATIO;
HIGH PH;
X-RAY;
D O I:
10.3390/molecules28114336
中图分类号:
Q5 [生物化学];
Q7 [分子生物学];
学科分类号:
071010 ;
081704 ;
摘要:
Here, we describe the behavior of mixtures of stearic acid (SA) and its hydroxylated counterpart 12-hydroxystearic acid (12-HSA) in aqueous mixtures at room temperature as a function of the 12-HSA/SA mole ratio R. The morphologies of the self-assembled aggregates are obtained through a multi-structural approach that combines confocal and cryo-TEM microscopies with small-angle neutron scattering (SANS) and wide-angle X-ray scattering (WAXS) measurements, coupled with rheology measurements. Fatty acids are solubilized by an excess of ethanolamine counterions, so that their heads are negatively charged. A clear trend towards partitioning between the two types of fatty acids is observed, presumably driven by the favorable formation of a H-bond network between hydroxyl OH function on the 12th carbon. For all R, the self-assembled structures are locally lamellar, with bilayers composed of crystallized and strongly interdigitated fatty acids. At high R, multilamellar tubes are formed. The doping via a low amount of SA molecules slightly modifies the dimensions of the tubes and decreases the bilayer rigidity. The solutions have a gel-like behavior. At intermediate R, tubes coexist in solution with helical ribbons. At low R, local partitioning also occurs, and the architecture of the self-assemblies associates the two morphologies of the pure fatty acids systems: they are faceted objects with planar domains enriched in SA molecules, capped with curved domains enriched in 12-HSA molecules. The rigidity of the bilayers is strongly increased, as well their storage modulus. The solutions remain, however, viscous fluids in this regime.
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