Novales Bruno, Navailles Laurence, Axelos Monique, Nallet Frédéric, Douliez Jean-Paul
UR1268, Biopolymères Interactions Assemblages, Institut National de la Recherche Agronomique, Equipe Interfaces et Systèmes Dispersés, rue de la Géraudière, Nantes, France.
Langmuir. 2008 Jan 1;24(1):62-8. doi: 10.1021/la7020929. Epub 2007 Nov 29.
We report the dispersions of a fatty acid and hydroxyl derivative salts in aqueous solutions that were further used to produce foams and emulsions. The tetrabutyl-ammonium salts of palmitic acid, 12-hydroxy stearic acid, and omega-hydroxy palmitic acid formed isotropic solutions of micelles, whereas the ethanolamine salts of the same acids formed turbid birefringent lamellar solutions. The structure and dimension of those phases were confirmed by small-angle neutron scattering and NMR. Micelles exhibited a surprisingly small radius of about 20 A, even for hydroxyl fatty acids, suggesting the formation of hydrogen bonds between lipids in the core of the micelles. In the case of ethanolamine salts of palmitic and 12-hydroxy stearic acids, the lipids were arranged in bilayers, with a phase transition from gel to fluid upon heating, whereas for omega-hydroxy palmitic acid, monolayers formed in accordance with the bola shape of this lipid. Foams and emulsions produced from ethanolamine salt solutions were more stable than those obtained from tetrabutyl-ammonium salt solutions. We discuss these results in terms of counterion size, lipid molecular shape, and membrane curvature.
我们报道了脂肪酸和羟基衍生物盐在水溶液中的分散情况，这些分散液进一步用于制备泡沫和乳液。棕榈酸、12-羟基硬脂酸和ω-羟基棕榈酸的四丁基铵盐形成了胶束的各向同性溶液，而相同酸的乙醇胺盐形成了浑浊的双折射层状溶液。这些相的结构和尺寸通过小角中子散射和核磁共振得以证实。胶束的半径出奇地小，约为20埃，即使对于羟基脂肪酸也是如此，这表明在胶束核心的脂质之间形成了氢键。在棕榈酸和12-羟基硬脂酸的乙醇胺盐的情况下，脂质排列成双层，加热时会发生从凝胶到流体的相变，而对于ω-羟基棕榈酸，根据该脂质的bola形状形成单层。由乙醇胺盐溶液产生的泡沫和乳液比由四丁基铵盐溶液获得的更稳定。我们根据抗衡离子大小、脂质分子形状和膜曲率来讨论这些结果。
