Kurtisovski Erol, Taulier Nicolas, Ober Raymond, Waks Marcel, Urbach Wladimir
Laboratoire de Physique Statistique, Ecole Normale Supérieure de Paris, CNRS UMR8550, 24 rue Lhomond, 75005 Paris, France.
Phys Rev Lett. 2007 Jun 22;98(25):258103. doi: 10.1103/PhysRevLett.98.258103. Epub 2007 Jun 21.
The behavior of the bending modulus kappa of bilayers in lamellar phases was studied by Small Angle X-ray Scattering technique for various nonionic C(i)E(j) surfactants. The bilayers are either unswollen and dispersed in water or swollen by water and dispersed in dodecane. For unswollen bilayers, the values of kappa decrease with both an increase in the area per surfactant molecule and in the polar head length. They increase when the aliphatic chain length increases at constant area per surfactant molecule. Whereas for water-swollen membranes, the values of kappa decrease as the content of water increases converging to the value of the single monolayer bending modulus. Such a behavior results from the decoupling of the fluctuations of the two surfactant membrane monolayers. Our results emphasize the determinant contribution of the surfactant conformation to kappa.
利用小角X射线散射技术研究了层状相中双层膜弯曲模量κ对于各种非离子型C(i)E(j)表面活性剂的行为。双层膜要么未溶胀并分散在水中，要么被水溶胀并分散在十二烷中。对于未溶胀的双层膜，κ值随每个表面活性剂分子的面积增加以及极性头部长度增加而降低。当每个表面活性剂分子的面积恒定时，随着脂肪链长度增加，κ值增大。而对于水溶胀的膜，κ值随着水含量增加而降低，趋近于单层弯曲模量的值。这种行为是由于两个表面活性剂膜单层波动的解耦所致。我们的结果强调了表面活性剂构象对κ的决定性贡献。
