Key Laboratory of Functional Polymer Materials, Ministry of Education, and Institute of Polymer Chemistry, Nankai University, Tianjin 300071, China.
Phys Chem Chem Phys. 2010 Oct 7;12(37):11380-9. doi: 10.1039/b927056f. Epub 2010 Aug 16.
To explore the structure and property features of complex aggregates assembled by polymer and organic dye molecules in microcosmic soft confined space, a three-dimensional microconfinement is constructed by W/O inverse emulsion as the site for the complex aggregation of 5,10,15,20-tetrakis(4-sulfonatophenyl)porphyrin (TPPS) and poly(ethylene glycol)-block-poly(4-vinylpyridine) (PEG-b-P4VP). It is found that porphyrin molecules exist in emulsion droplets mainly as the deprotonated monomer form, even though the pH of the water phase is much lower than the pK(a) of TPPS in bulk (pK(a)≈ 4.7). In spatially confined circumstances, upon blending of the single-component emulsions, complex aggregates are formed due to the thermodynamic collision of emulsion droplets and the subsequent electrostatic interaction between TPPS and polymer. The resultant novel complexes possess a relatively precise structure and homogenous core consisting of a porphyrin and P4VP block. Upon emulsion-breaking, the metastable complex kinetic intermediates generated in original acidic emulsion droplets display a remarkable trend of reaggregation within a certain period of time followed by a disassociation and redispersion. Complex aggregates with some novel morphologies are observed. The final product has a core-shell structure with the electrostatic complex of deprotonized porphyrin molecules homogenously dispersing in the P4VP clew as the core and the soluble PEG as the shell. However, those complexes produced in basic emulsion droplets exhibit a relatively higher stability against further aggregation after breakage of emulsion.
为了探索在微观软受限空间中由聚合物和有机染料分子组装而成的复杂聚集体的结构和性能特征，我们采用 W/O 反相乳液作为 5,10,15,20-四(4-磺酸钠苯基)卟啉（TPPS）和聚（乙二醇）-嵌段-聚（4-乙烯基吡啶）（PEG-b-P4VP）复杂聚集的微区，构建了一个三维微区。结果发现，即使水相的 pH 值远低于本体中 TPPS 的 pK(a)（pK(a)≈4.7），卟啉分子在乳液液滴中主要以去质子化单体的形式存在。在空间受限的情况下，在单一成分乳液混合时，由于乳液液滴的热力学碰撞以及随后 TPPS 和聚合物之间的静电相互作用，形成了复杂的聚集体。所得的新型配合物具有相对精确的结构和均匀的核心，由卟啉和 P4VP 嵌段组成。乳液破乳后，在原始酸性乳液液滴中生成的亚稳配合物动力学中间体在一定时间内显示出明显的再聚集趋势，随后发生解离和再分散。观察到具有一些新颖形态的复杂聚集体。最终产物具有核壳结构，带负电的卟啉分子的静电复合物均匀地分散在 P4VP 芯作为核，可溶性 PEG 作为壳。然而，在碱性乳液液滴中生成的那些配合物在乳液破乳后进一步聚集时表现出相对较高的稳定性。
