Max-Planck-Institut für Intelligente Systeme, Heisenbergstraße 3, 70569 Stuttgart, Germany.
J Chem Phys. 2012 Jun 14;136(22):224903. doi: 10.1063/1.4722884.
We consider an ensemble of spherical colloidal particles immersed in a near-critical solvent such as a binary liquid mixture close to its critical demixing point. The emerging long-ranged fluctuations of the corresponding order parameter of the solvent drive the divergence of the correlation length. Spatial confinements of these critical fluctuations by colloidal solute particles, acting as cavities in the fluctuating medium, restrict and modify the fluctuation spectrum in a way which depends on their relative configuration. This results in effective, so-called critical Casimir forces (CCFs) acting on the confining surfaces. Using the available knowledge about CCFs we study the structure and stability of such colloidal suspensions by employing an approach in terms of effective, one-component colloidal systems. Applying the approximation of pairwise additive CCFs we calculate the radial distribution function of the colloids, which is experimentally accessible. We analyze colloidal aggregation due to CCFs and thus allude to previous experimental studies which are still under debate.
我们考虑一组沉浸在近临界溶剂中的球形胶体颗粒，例如接近其临界分相点的二元液体混合物。溶剂相应序参量的出现的长程涨落驱动相关长度的发散。胶体溶质颗粒通过在不断变化的介质中充当腔室来对这些临界涨落进行空间限制，并以依赖于其相对构型的方式限制和修改涨落谱。这导致作用在限制表面上的有效，所谓的临界 Casimir 力（CCF）。我们使用关于 CCF 的现有知识，通过采用有效，单组分胶体系统的方法来研究此类胶体悬浮液的结构和稳定性。通过应用可加性 CCF 的近似值，我们计算了胶体的径向分布函数，这是实验上可获得的。我们分析了由于 CCF 引起的胶体聚集，从而暗示了以前仍在讨论中的实验研究。
