Fridrich Petr, Posel Zbyšek
Department of Informatics, Faculty of Science, Jan Evangelista Purkyně University in Ústí nad Labem, 400 96 Ústí nad Labem, Czech Republic.
Polymers (Basel). 2024 Mar 6;16(5):721. doi: 10.3390/polym16050721.
Y-shaped polymer brushes represent a special class of binary mixed polymer brushes, in which a combination of different homopolymers leads to unique phase behavior. While most theoretical and simulation studies use monodisperse models, experimental systems are always polydisperse. This discrepancy hampers linking theoretical and experimental results. In this theoretical study, we employed dissipative particle dynamics to study the influence of polydispersity on the phase behavior of Y-shaped brushes grafted to flat surfaces under good solvent conditions. Polydispersity was kept within experimentally achievable values and was modeled via Schulz-Zimm distribution. In total, 10 systems were considered, thus covering the phase behavior of monodisperse, partially polydisperse and fully polydisperse systems. Using such generic representation of real polymers, we observed a rippled structure and aggregates in monodisperse systems. In addition, polydisperse brushes formed a stable perforated layer not observed previously in monodisperse studies, and influenced the stability of the remaining phases. Although the perforated layer was experimentally observed under good solvent conditions and in the melt state, further confirmation of its presence in systems under good solvent conditions required mapping real polymers onto mesoscale models that reflected, for example, different polymer rigidity, and excluded volume effects or direct influence of the surface, just to mention a few parameters. Finally, in this work, we show that mesoscale modeling successfully describes polydisperse models, which opens the way for rapid exploring of complex systems such as polydisperse Y-shaped brushes in selective or bad solvents or under non-equilibrium conditions.
Y形聚合物刷代表了一类特殊的二元混合聚合物刷，其中不同均聚物的组合导致独特的相行为。虽然大多数理论和模拟研究使用单分散模型，但实验系统总是多分散的。这种差异阻碍了理论结果与实验结果的联系。在这项理论研究中，我们采用耗散粒子动力学来研究在良溶剂条件下接枝到平面上的Y形刷的多分散性对其相行为的影响。多分散性保持在实验可实现的值范围内，并通过舒尔茨-齐姆分布进行建模。总共考虑了10个系统，从而涵盖了单分散、部分多分散和完全多分散系统的相行为。使用这种真实聚合物的通用表示，我们在单分散系统中观察到了波纹结构和聚集体。此外，多分散刷形成了一个稳定的穿孔层，这在之前的单分散研究中未曾观察到，并且影响了其余相的稳定性。尽管在良溶剂条件和熔体状态下通过实验观察到了穿孔层，但要进一步证实其在良溶剂条件下的系统中的存在，需要将真实聚合物映射到反映例如不同聚合物刚性、排除体积效应或表面直接影响等几个参数的介观尺度模型上。最后，在这项工作中，我们表明介观尺度建模成功地描述了多分散模型，这为快速探索复杂系统（如在选择性或不良溶剂中或在非平衡条件下的多分散Y形刷）开辟了道路。
