Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry & Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB, the Netherlands.
Laboratory of Physical Chemistry, Department of Chemical Engineering and Chemistry & Institute for Complex Molecular Systems, Eindhoven University of Technology, P.O. Box 513, Eindhoven, 5600 MB, the Netherlands.
J Colloid Interface Sci. 2022 Feb 15;608(Pt 1):644-651. doi: 10.1016/j.jcis.2021.09.090. Epub 2021 Sep 22.
Mixtures of colloids and supramolecular polymers may exhibit stimuli-responsive phase behaviour. However, in theoretical descriptions of such systems, the polymers are commonly described either as flexible chains or as rigid rods, while in experimental systems supramolecular polymers usually fall in between these two limits. We expect the flexibility of the polymers to have a profound effect on the stimuli-responsive phase behaviour.
We propose a general approach to predict the phase behaviour of colloidal hard spheres mixed with covalent or supramolecular polymers of arbitrary persistence length using free volume theory and an interpolation between flexible and rigid chains.
The binodals are predicted to shift to lower monomer concentrations as the persistence length is increased, making the polymers more efficient depletants. The persistence length is therefore an additional degree of freedom for manipulating the phase behaviour of colloid-polymer mixtures. We show that by manipulating the persistence length of temperature responsive supramolecular polymers, a wide range of phase diagrams with various topologies can be obtained. For example, we find phase diagrams with a critical point but no triple point or displaying two triple points for temperature-sensitive supramolecular polymers mixed with hard spheres.
胶体和超分子聚合物的混合物可能表现出对刺激的响应相行为。然而，在对这类系统的理论描述中，聚合物通常被描述为柔性链或刚性棒，而在实验系统中超分子聚合物通常介于这两个极限之间。我们预计聚合物的柔韧性会对刺激响应相行为产生深远的影响。
我们提出了一种通用方法，使用自由体积理论和柔性链与刚性链之间的插值，来预测胶体硬球与任意持久性长度的共价或超分子聚合物混合的相行为。
随着持久性长度的增加，双结点被预测会向更低的单体浓度移动，从而使聚合物成为更有效的耗尽剂。因此，持久性长度是操纵胶体-聚合物混合物相行为的另一个自由度。我们表明，通过操纵温度响应超分子聚合物的持久性长度，可以获得具有各种拓扑结构的广泛相图。例如，我们发现对于与硬球混合的温度敏感超分子聚合物，相图具有临界点但没有三相点或显示两个三相点。
