Baciu Magdalena, Olsson Ulf, Leaver Marc S, Holmes Michael C
Department of Physics, Astronomy and Mathematics, Center For Materials Science, University of Central Lancashire, Preston, PR1 2HE, Lancashire, UK.
J Phys Chem B. 2006 Apr 27;110(16):8184-7. doi: 10.1021/jp0611323.
Random mesh phases share many common features with the classical lamellar phase in that they are layered phases; but crucially, they possess nonuniform interfacial curvature, since the lamellae are pierced by water-filled pores. The introduction of curvature into the lamellae has been posited as a transitional precursor for other lyotropic phases. In this paper, we show that simple 2H nuclear magnetic resonance (NMR) experiments provide strong indication for the formation of the random mesh phase and the NMR data correlate well with literature results from small-angle X-ray scattering. The thermal evolution of the recorded quadrupolar splitting (DeltanuQ) is monitored within the lamellar phase of two nonionic surfactants, C16E6 and C12E5, as the samples are cooled or heated, and a marked and reversible change in the evolution of DeltanuQ is observed. Data from heavy water and deuterium labeled surfactant show the same temperature dependence and consequently report on the same structural changes with temperature. The formation of the random mesh phase is quantified in terms of an effective order parameter that is unity in the classical lamellar phase and takes values of <1 in the random mesh phase, reaching 0.6 at lower temperatures.
随机网状相和经典层状相有许多共同特征，因为它们都是层状相；但关键的是，它们具有不均匀的界面曲率，因为层片被充满水的孔隙所贯穿。层片中引入曲率被认为是其他溶致相的过渡前驱体。在本文中，我们表明简单的2H核磁共振（NMR）实验为随机网状相的形成提供了有力证据，并且NMR数据与小角X射线散射的文献结果相关性良好。在两种非离子表面活性剂C16E6和C12E5的层状相中，当样品冷却或加热时，监测记录的四极分裂（DeltanuQ）的热演化，观察到DeltanuQ演化中有明显且可逆的变化。来自重水和氘标记表面活性剂的数据显示出相同的温度依赖性，因此报告了相同的随温度的结构变化。随机网状相的形成通过一个有效序参数量化，该序参数在经典层状相中为1，在随机网状相中取值<1，在较低温度下达到0.6。
