Peng Bo, Imhof Arnout
Soft Condensed Matter, Debye Institute for Nanomaterials Science, Utrecht University, Princetonplein 5, 3584 CC Utrecht, The Netherlands.
Soft Matter. 2015 May 14;11(18):3589-98. doi: 10.1039/c5sm00606f.
Cross-linked polymer colloids (poly(methyl methacrylate) and polystyrene) with diverse shapes were prepared in polar solvents (ethanol, methanol and water) via dispersion polymerization, in which a linear addition of the cross-linker was used during reaction. Apart from spherical particles we found dented spheres or particles covered with nodules, or a combination of both. A comprehensive investigation was carried out, mainly concentrating on the effect of the experimental conditions (e.g., the addition start time and total addition time, cross-linker density and the solvency of the solvents) on particle morphologies. Consequently, we suggest a number of effective ways for the synthesis of regular (spherical) colloidal particles through maintaining a relatively low concentration of the cross-linker during the entire reaction, or forcing the co-polymerization (of monomer and cross-linker) locus to the continuous medium, or using a high quality or quantity of the stabilizer. Moreover, the size of the particles was also precisely manipulated by varying the polarity of the solvents, the concentration of the cross-linker, and the amount and average molecular weight of the stabilizer. In addition, the formation of the heavily dented particles with a very rough surface prepared under a pure or oxygen-'contaminated' nitrogen environment was monitored over time. The results accumulated in this article are of use for a better understanding of the mechanism of the polymerization and control over the structure and property of polymer particles.
通过分散聚合在极性溶剂（乙醇、甲醇和水）中制备了具有不同形状的交联聚合物胶体（聚甲基丙烯酸甲酯和聚苯乙烯），反应过程中采用交联剂线性添加方式。除了球形颗粒外，我们还发现了凹陷球体或表面覆盖有结节的颗粒，或两者兼具的颗粒。开展了全面研究，主要聚焦于实验条件（如添加起始时间和总添加时间、交联剂密度以及溶剂的溶解能力）对颗粒形态的影响。因此，我们提出了一些有效方法来合成规则（球形）胶体颗粒，包括在整个反应过程中保持较低的交联剂浓度、促使（单体和交联剂的）共聚位点进入连续介质或使用高质量或高用量的稳定剂。此外，通过改变溶剂极性、交联剂浓度以及稳定剂的用量和平均分子量，还能精确控制颗粒大小。另外，对在纯氮或氧气“污染”的氮气环境下制备的表面非常粗糙的严重凹陷颗粒的形成过程进行了长期监测。本文积累的结果有助于更好地理解聚合机理并控制聚合物颗粒的结构和性能。
