Glagoleva A A, Larin D E, Vasilevskaya V V
A. N. Nesmeyanov Institute of Organoelement Compounds, Russian Academy of Sciences, Moscow 119991, Russia.
Polymers (Basel). 2020 Apr 10;12(4):871. doi: 10.3390/polym12040871.
By means of computer simulation and analytical theory, we first demonstrated that the interpolyelectrolyte complexes in dilute solution can spontaneously form hollow spherical particles with thin continuous shells (vesicles) or with porous shells (perforated vesicles) if the polyions forming the complex differ in their affinity for the solvent. The solvent was considered good for the nonionic groups of one macroion and its quality was varied for the nonionic groups of the other macroion. It was found that if the electrostatic interactions are weak compared to the attraction induced by the hydrophobicity of the monomer units, the complex in poor solvent tends to form "dense core-loose shell" structures of different shapes. The strong electrostatic interactions favor the formation of the layered, the hollow, and the filled structured morphologies with the strongly segregated macroions. Vesicles with perforated walls were distinguished as the intermediate between the vesicular and the structured solid morphologies. The order parameter based on the spherical harmonics expansion was introduced to calculate the pore distribution in the perforated vesicles depending on the solvent quality. The conditions of the core-shell and hollow vesicular-like morphologies formation were determined theoretically via the calculations of their free energy. The results of the simulation and theoretical approaches are in good agreement.
通过计算机模拟和分析理论，我们首先证明，如果形成复合物的聚离子对溶剂的亲和力不同，稀溶液中的聚电解质复合物能够自发形成具有薄连续壳层的空心球形颗粒（囊泡）或具有多孔壳层的颗粒（穿孔囊泡）。对于一种大分子离子的非离子基团，溶剂被认为是良溶剂，而对于另一种大分子离子的非离子基团，溶剂的性质是可变的。结果发现，如果与单体单元疏水性诱导的吸引力相比，静电相互作用较弱，那么在不良溶剂中的复合物倾向于形成不同形状的“致密核-松散壳”结构。强静电相互作用有利于形成具有强烈分离的大分子离子的层状、空心和填充结构形态。具有穿孔壁的囊泡被认为是囊泡形态和结构化固体形态之间的中间形态。引入基于球谐展开的序参量来计算穿孔囊泡中取决于溶剂性质的孔分布。通过计算核壳和空心囊泡状形态的自由能，从理论上确定了它们形成的条件。模拟和理论方法的结果吻合良好。
