Cracow University of Technology, Warszawska 24, 31-155 Krakow, Poland.
J Chem Phys. 2013 Aug 21;139(7):074903. doi: 10.1063/1.4818579.
The effective diffusivity in a polymer matrix modified with inclusions is usually calculated based on Kalnin-Kotomin's model [J. R. Kalnin, E. A. Kotomin, and J. Maier, J. Phys. Chem. Solids 63, 449-456 (2002)], which extends the well known Maxwell-Garnett formula. Kalnin-Kotomin's model correctly predicts effective diffusivity for stationary diffusion or for infinite media. In the present paper diffusion in composite media is studied for finite systems under transient conditions. The process of diffusion is modeled numerically and effective diffusion coefficient in the transient state is estimated, which, under certain conditions, is different from the predictions of the Kalnin-Kotomin's model. An analytical model is proposed to explain deviations of the transient effective coefficient of diffusion from the stationary case.
用夹杂体改性的聚合物基体中的有效扩散系数通常基于 Kalnin-Kotomin 模型 [J. R. Kalnin、E. A. Kotomin 和 J. Maier，J. Phys. Chem. Solids 63, 449-456（2002）] 来计算，该模型扩展了著名的 Maxwell-Garnett 公式。Kalnin-Kotomin 模型可以正确预测静止扩散或无限介质中的有效扩散系数。在本文中，研究了在瞬态条件下有限系统中的复合介质中的扩散。扩散过程通过数值建模，并估计了瞬态状态下的有效扩散系数，在某些条件下，该系数与 Kalnin-Kotomin 模型的预测值不同。提出了一个分析模型来解释瞬态有效扩散系数与静止情况的偏差。
