Lisy V, Brutovsky B
Department of Biophysics, P. J. Safarik University, Jesenna 5, 041 54 Kosice, Slovakia.
Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 2000 Apr;61(4 Pt B):4045-53. doi: 10.1103/physreve.61.4045.
The theory of static and dynamic scattering of neutrons and light on microemulsion droplets is developed. The droplets are modeled by double-layered fluid spheres immersed in another fluid. The surface layer of arbitrary thickness thermally fluctuates in the shape. The scattering functions are consistently calculated up to the second order of the fluctuations. The bulk fluids and the layer are characterized by different scattering length densities (or dielectric constants). Involving the Helfrich's concept of interfacial elasticity, the theory is applied for the description of small-angle neutron scattering (SANS), neutron spin echo (NSE), and dynamic light scattering (DLS) experiments on dilute microemulsions. From the fits to the experimental data the bending elasticity and the Gaussian modulus are extracted. Due to the corrected account for the fluctuations, their values differ markedly from those obtained in the original works. The theory well describes the SANS experiments. In the case of DLS, we had to assume the shell of the solvent molecules to be built of several layers. Previous theories were in a sharp disagreement with the NSE experiments. A better agreement with these experiments is obtained if the dissipation in the surface layer is included into the consideration. From the experiments, the viscosity of the layer is estimated for a concrete microemulsion system.
本文建立了中子和光在微乳液滴上的静态和动态散射理论。液滴由浸没在另一种流体中的双层流体球模拟。任意厚度的表面层形状会发生热涨落。散射函数一直计算到涨落的二阶。主体流体和表面层由不同的散射长度密度（或介电常数）表征。结合赫尔弗里希的界面弹性概念，该理论用于描述稀微乳液的小角中子散射（SANS）、中子自旋回波（NSE）和动态光散射（DLS）实验。通过对实验数据的拟合，提取了弯曲弹性和高斯模量。由于对涨落进行了修正，它们的值与原始文献中的值有显著差异。该理论很好地描述了SANS实验。在DLS的情况下，我们不得不假设溶剂分子壳由几层构成。先前的理论与NSE实验存在明显分歧。如果将表面层的耗散纳入考虑，则与这些实验能获得更好的一致性。通过实验，对具体的微乳液体系估计了表面层的粘度。
