Bataller Henri, Triller Thomas, Pur Bastian, Köhler Werner, Ortiz de Zárate José Maria, Croccolo Fabrizio
Univ Pau & Pays Adour, CNRS, TOTAL, LFCR-IPRA, UMR5150, 1 Allée du Parc Montaury, 64600, Anglet, France.
Physikalisches Institut, Universität Bayreuth, D-95440, Bayreuth, Germany.
Eur Phys J E Soft Matter. 2017 Mar;40(3):35. doi: 10.1140/epje/i2017-11522-8. Epub 2017 Mar 30.
Dynamic analysis of the light scattered by non-equilibrium fluctuations in a thermodiffusion experiment has been performed on a sample of polystyrene-toluene-n -hexane, at 0.9-49.55-49.55% mass fraction. Time decays of the non-equilibrium fluctuations have been obtained revealing the accurate detectability of three modes. The slowest mode has been attributed to the mass diffusion of the polymer into the binary solvent; the intermediate one to mass diffusion of the two molecular components of the solvent; finally, the fastest one has been attributed to the thermal diffusivity of the overall mixture. The two eigenvalues of the mass diffusion matrix have been evaluated with accuracy in the order of 1%. Neglecting cross-diffusion effects we obtain a simplified expression for the relative amplitude of the two mass diffusion modes, allowing a parameterized determination of polystyrene and toluene Soret coefficients in the ternary mixture. We suggest that a two wavelength shadowgraph experiment is needed for a complete determination of all the coefficients.
在质量分数为0.9 - 49.55 - 49.55%的聚苯乙烯 - 甲苯 - 正己烷样品上，对热扩散实验中非平衡涨落所散射光进行了动态分析。已获得非平衡涨落的时间衰减，揭示了三种模式的准确可探测性。最慢的模式归因于聚合物向二元溶剂中的质量扩散；中间的模式归因于溶剂的两种分子成分的质量扩散；最后，最快的模式归因于整个混合物的热扩散率。质量扩散矩阵的两个本征值已精确到1%量级进行了评估。忽略交叉扩散效应，我们得到了两种质量扩散模式相对振幅的简化表达式，从而能够对三元混合物中聚苯乙烯和甲苯的索雷特系数进行参数化测定。我们建议需要进行双波长阴影图实验来完整确定所有系数。
