Alexander Nathan P, Phillips Ronald J, Dungan Stephanie R
Department of Chemical Engineering, University of California at Davis, Davis, CA 95616, USA.
Soft Matter. 2021 Jan 21;17(3):531-542. doi: 10.1039/d0sm01406k. Epub 2020 Nov 11.
Ternary diffusion coefficient matrices [D] were measured using the Taylor dispersion method, for crowded aqueous solutions of decaethylene glycol monododecyl ether (CE) with either decane or limonene solute. The matrix [D], for both systems, was found to be highly non-diagonal, and concentration dependent, over a broad domain of solute to surfactant molar ratios and micelle volume fractions. A recently developed theoretical model, based on Batchelor's theory for gradient diffusion in dilute, polydisperse mixtures of interacting spheres, was simplified by neglecting local polydispersity, and effectively used to predict [D] with no adjustable parameters. Even though the model originates from dilute theory, the theoretical results were in surprisingly good agreement with experimental data for concentrated mixtures, with volume fractions up to φ≈ 0.47. In addition, the theory predicts eigenvalues D and D that correspond to long-time self and gradient diffusion coefficients, respectively, for monodisperse spheres, in reasonable agreement with experimental data.
使用泰勒分散法测量了三元扩散系数矩阵[D]，该矩阵针对含有癸烷或柠檬烯溶质的十聚乙二醇单十二烷基醚（CE）的拥挤水溶液。对于这两个体系，发现矩阵[D]在溶质与表面活性剂摩尔比和胶束体积分数的广泛范围内高度非对角且与浓度相关。基于Batchelor关于相互作用球体的稀溶液、多分散混合物中梯度扩散的理论，最近开发的一个理论模型通过忽略局部多分散性进行了简化，并有效地用于预测[D]，且无需可调参数。尽管该模型源于稀溶液理论，但理论结果与体积分数高达φ≈0.47的浓混合物的实验数据惊人地吻合。此外，该理论预测的本征值D和D分别对应于单分散球体的长时间自扩散系数和梯度扩散系数，与实验数据合理吻合。
