Department de Tecnologia Química i de Tensioactius, IQAC-CSIC E08034 Barcelona, Spain.
Langmuir. 2010 Feb 16;26(4):2256-62. doi: 10.1021/la902672j.
A systematic study of the diluted lamellar phases of the OG/C(12)E(4) system with different alkanols has been carried out by small-angle X-ray scattering (SAXS). The measurements have been made as a function of both the concentration and the alcohol type. Several different form factor models have been used to estimate the differences in bilayer topology induced by the presence of alcohol. For the infinite lamellae form factor (with a high-low-high electronic density profile across the membrane), there is a good fitting of samples with a X(OG) = 0.1 ratios. Only the free parameters correspond to the pseudomolecule composition and hydration number, which resulted in two water molecules per ethylene oxide group in the polar head irrespective of the alkanol chain length and concentration. However, samples with higher OG content can be quite well fitted by a core-shell disk model. For the samples with higher OG content, we find the participation of OG in the disks to be important. From the line-shape analysis of SAXS data, the half-thickness of the hydrophobic layer and the thickness of the hydrophilic layer have also been obtained. The results suggest significant mixing of the surfactant acyl chains corresponding to both sides of the lamellae and the transition from vesicles to open bilayer fragments without macroscopic phase separation.
采用小角 X 射线散射（SAXS）对具有不同醇的 OG/C(12)E(4)体系的稀释层状相进行了系统研究。测量是作为浓度和醇类型的函数进行的。已经使用了几种不同的形状因子模型来估计醇存在引起的双层拓扑结构的差异。对于无限层状形状因子（在膜中具有高低高电子密度分布），对于 X(OG) = 0.1 比值的样品有很好的拟合。只有自由参数对应于伪分子组成和水合数，这导致在极性头中每个氧化乙烯基团有两个水分子，而与醇链长和浓度无关。然而，具有更高 OG 含量的样品可以通过核壳盘模型很好地拟合。对于具有更高 OG 含量的样品，我们发现 OG 参与盘的情况很重要。从 SAXS 数据的线形状分析中，还获得了疏水区的半厚度和亲水区的厚度。结果表明，层状两侧的表面活性剂酰链发生了明显的混合，并且在没有宏观相分离的情况下从囊泡转变为开放双层片段。
