Ghosh Supriyo, Mukherjee Arnab, Abinandanan T A, Bose Suryasarathi
Materials Engineering Department, Indian Institute of Science, Bangalore 560012, India.
Phys Chem Chem Phys. 2017 Jun 14;19(23):15424-15432. doi: 10.1039/c7cp01816a.
We have used mesoscale simulations to study the effect of immobile particles on microstructure formation during spinodal decomposition in ternary mixtures such as polymer blends. Specifically, we have explored a regime of interparticle spacings (which are a few times the characteristic spinodal length scale) in which we might expect interesting new effects arising from interactions among wetting, spinodal decomposition and coarsening. In this paper, we report three new effects for systems in which the particle phase has a strong preference for being wetted by one of the components (say, A). In the presence of particles, microstructures are not bicontinuous in a symmetric mixture. An asymmetric mixture, on the other hand, first forms a non-bicontinuous microstructure which then evolves into a bicontinuous one at intermediate times. Moreover, while wetting of the particle phase by the preferred component (A) creates alternating A-rich and B-rich layers around the particles, curvature-driven coarsening leads to shrinking and disappearance of the first A-rich layer, leaving a layer of the non-preferred component in contact with the particle. At late simulation times, domains of the matrix components coarsen following the Lifshitz-Slyozov-Wagner law, R(t) ∼ t.
我们利用介观模拟研究了三元混合物（如聚合物共混物）在旋节线分解过程中固定粒子对微观结构形成的影响。具体而言，我们探索了粒子间距的一种状态（其为特征旋节线长度尺度的几倍），在这种状态下，我们可能期望从润湿性、旋节线分解和粗化之间的相互作用中产生有趣的新效应。在本文中，我们报告了粒子相对其中一种组分（比如A）具有强烈被润湿性的体系的三种新效应。在存在粒子的情况下，对称混合物中的微观结构不是双连续的。另一方面，非对称混合物首先形成非双连续的微观结构，然后在中间时刻演变成双连续结构。此外，虽然优选组分（A）对粒子相的润湿性会在粒子周围形成富含A和富含B的交替层，但曲率驱动的粗化会导致第一个富含A的层收缩并消失，留下一层非优选组分与粒子接触。在模拟后期，基体组分的区域按照Lifshitz-Slyozov-Wagner定律粗化，R(t) ∼ t 。
