Tuinier R, Ouhajji S, Linse P
Laboratory of Physical Chemistry (SPC), Department of Chemical Engineering and Chemistry & Institute for Complex Molecular Systems (ICMS), Eindhoven University of Technology, Helix STO 2.49, P.O. Box 513, 5600 MB, Eindhoven, The Netherlands.
Van 't Hoff Laboratory for Physical and Colloid Chemistry, Department of Chemistry & Debye Institute, Utrecht University, Padualaan 8, 3584 CH, Utrecht, The Netherlands.
Eur Phys J E Soft Matter. 2016 Nov;39(11):115. doi: 10.1140/epje/i2016-16115-5. Epub 2016 Nov 30.
The phase behaviour of a colloidal dispersion mediated by weakly adhesive polymers is considered. The polymers are depleted but are weakly adhesive and hence comprise a non-zero polymer concentration at the colloid's surface, in contrast to the classical assumption in depletion theories involving a zero polymer concentration at the surface. The theory is composed of a generalized free-volume theory for colloid-polymer mixtures and a self-consistent mean-field theory for polymers at surfaces. It is found that the weak adhesion of the polymers shifts the phase stability of the colloid-polymer mixtures to higher polymer concentrations as compared to assuming a full depletion effect. The predicted phase diagrams employing the new theory are consistent with experiments on mixtures of silica spheres coated with stearyl alcohol and polydimethylsiloxane in cyclohexane and with Monte Carlo simulation results.
研究了由弱粘附聚合物介导的胶体分散体系的相行为。聚合物发生耗尽，但具有弱粘附性，因此在胶体表面存在非零聚合物浓度，这与耗尽理论中的经典假设（表面聚合物浓度为零）不同。该理论由胶体 - 聚合物混合物的广义自由体积理论和表面聚合物的自洽平均场理论组成。结果发现，与假设完全耗尽效应相比，聚合物的弱粘附性将胶体 - 聚合物混合物的相稳定性转移到更高的聚合物浓度。采用新理论预测的相图与硬脂醇包覆的二氧化硅球和聚二甲基硅氧烷在环己烷中的混合物实验以及蒙特卡罗模拟结果一致。
