Ono Toshikazu, Ohta Masahiko, Sada Kazuki
Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Motooka, Nishi, Fukuoka, 819-0395, Japan.
Department of Chemistry, Graduate School of Science, Hokkaido University, Kita 10 Nishi 8, Kita-ku, Sapporo, 060-0810, Japan.
ACS Macro Lett. 2012 Nov 20;1(11):1270-1273. doi: 10.1021/mz3002879. Epub 2012 Oct 16.
Polyelectrolytes are ubiquitous materials, and their unique properties originate from dissociation of ionic groups to the small number of macromolecular ions and the large number of small counterions. They have been exploited only in water or high-dielectric media and scarcely in nonpolar ones (ε < 10). Herein, we demonstrate that poly(octadecyl acrylate) bearing tetraalkylammonium tetraarylborate as ionic groups behaves as a polyelectrolyte in the common nonpolar organic solvents such as chloroform, THF, and 1,2-dichloroethane. Conductivity measurement, DOSY NMR spectroscopy, and viscosity measurements clearly indicate that they form the extended conformation in them. This result emphasizes that the ionic polymers bearing suitable ion pairs ionizable in the given media act as polyelectrolytes. Various characteristic properties and processes of polyelectrolytes should be realized in nonpolar media by designing ion pairs and polymer chains in the ionic polymers. Moreover, our results imply that electrostatic interaction is readily available as a long-range repulsive force even in the nonpolar media.
聚电解质是普遍存在的材料，其独特性质源于离子基团解离为少量大分子离子和大量小反离子。它们仅在水或高介电常数介质中得到应用，而在非极性介质（ε < 10）中几乎未被使用。在此，我们证明了以四芳基硼酸四烷基铵为离子基团的聚（丙烯酸十八酯）在常见的非极性有机溶剂如氯仿、四氢呋喃和1,2 - 二氯乙烷中表现为聚电解质。电导率测量、扩散排序核磁共振光谱和粘度测量清楚地表明它们在这些溶剂中形成伸展构象。这一结果强调了在给定介质中带有可电离合适离子对的离子聚合物可作为聚电解质。通过设计离子聚合物中的离子对和聚合物链，聚电解质的各种特性和过程应能在非极性介质中实现。此外，我们的结果表明，即使在非极性介质中，静电相互作用也很容易作为一种长程排斥力存在。
