Kimura Hiroshi
Department of Chemistry and Biomolecular Science, Faculty of Engineering, Gifu University, Gifu 501-1193, Japan.
Materials (Basel). 2024 Dec 29;18(1):98. doi: 10.3390/ma18010098.
When an electric field is applied to or removed from colloidal particle aqueous dispersions, a reversible increase in sedimentation velocity of the colloidal particles, referred to as the Electrically Induced Rapid Separation (ERS) effect, is observed. While electrophoresis and other interfacial electrokinetic phenomena under applied electric fields are well-studied, the phenomena of particle aggregation and re-dispersion caused by the application and removal of the field remain largely unexplored despite their significance. Experiments using mixed aqueous dispersions of poly (methyl methacrylate) (PMMA) particles of different sizes revealed that applying an electric field induced the formation of co-flocs involving both large and small particles, significantly enhancing the sedimentation velocity. It was also observed that slight vibrational deformation hindered the ERS effect. Under uniform electrolyte concentration conditions, the ERS effect was found to depend on pH, with a stronger effect observed when the absolute value of the zeta potential was larger. These findings indicate that the presence of the electric double layer plays a crucial role in the manifestation of the ERS effect. The results of this study provide critical insights for the further application of the ERS effect.
当对胶体颗粒水性分散体施加电场或去除电场时，会观察到胶体颗粒沉降速度出现可逆增加，这被称为电场诱导快速分离（ERS）效应。虽然施加电场下的电泳和其他界面电动现象已得到充分研究，但尽管电场的施加和去除所引起的颗粒聚集和再分散现象具有重要意义，却在很大程度上仍未得到探索。使用不同尺寸的聚（甲基丙烯酸甲酯）（PMMA）颗粒的混合水性分散体进行的实验表明，施加电场会诱导形成包含大颗粒和小颗粒的共絮凝物，显著提高沉降速度。还观察到轻微的振动变形会阻碍ERS效应。在均匀电解质浓度条件下，发现ERS效应取决于pH值，当ζ电位的绝对值较大时，观察到的效应更强。这些发现表明，双电层的存在在ERS效应的表现中起着关键作用。本研究结果为ERS效应的进一步应用提供了重要见解。
