Ilyasov Leonid O, Ogawa Kazuyoshi, Panova Irina G, Yaroslavov Alexander A, Adachi Yasuhisa
Department of Chemistry, Lomonosov Moscow State University, Leninskie gory 1-3, Moscow 119991, Russia.
Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1, Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
Langmuir. 2020 Jul 28;36(29):8375-8383. doi: 10.1021/acs.langmuir.0c00619. Epub 2020 Jul 1.
The initial-stage dynamics of flocculation of positively charged latex particles induced by polyelectrolytes (PEs) and polyelectrolyte complexes (PECs), composed of linear polyacrylic acid (PAA) and a PAA-based hydrophilic microgel (PAA#) with a small amount of a linear polycation, was comparatively analyzed by applying the standardized colloidal mixing procedure. Based on the rate of flocculation, this method allows us to investigate the dynamics of flocculation immediately after the onset. In addition to confirming the prediction made regarding the initial rate of flocculation with linear polyanions-which was mostly similar to that observed in negatively charged colloids with positively charged PEs-we have confirmed two important new results regarding the microgel: (1) the increase of the initial rate is less markedly affected by the microgel concentration than by the linear polymer concentration, which can be explained by the fact that the three-dimensional (3D) cross-linked structure of the microgel that does not deform as easily as the linear structure upon touching the colloidal surface; and (2) there is a remarkable increase of the initial rate due to the contribution of instant aggregation of the negatively charged microgel induced by the polycation adsorption. These results suggest the significance of state and formation dynamics of PECs prior to reaching the surface of targeted colloidal particles for the intension of effective flocculation. These aspects are not treated so far in the dynamic process of flocculation.
通过应用标准化的胶体混合程序，对由线性聚丙烯酸（PAA）和含有少量线性聚阳离子的基于PAA的亲水性微凝胶（PAA#）组成的聚电解质（PEs）和聚电解质复合物（PECs）诱导的带正电乳胶颗粒絮凝的初始阶段动力学进行了比较分析。基于絮凝速率，该方法使我们能够在絮凝开始后立即研究絮凝动力学。除了证实关于线性聚阴离子絮凝初始速率的预测（这与在带正电的PEs的带负电胶体中观察到的情况大多相似）之外，我们还证实了关于微凝胶的两个重要新结果：（1）初始速率的增加受微凝胶浓度的影响不如受线性聚合物浓度的影响明显，这可以通过以下事实来解释，即微凝胶的三维（3D）交联结构在接触胶体表面时不像线性结构那样容易变形；（2）由于聚阳离子吸附诱导的带负电微凝胶的瞬间聚集的贡献，初始速率有显著增加。这些结果表明，在到达目标胶体颗粒表面之前，PEC的状态和形成动力学对于有效絮凝的强度具有重要意义。到目前为止，在絮凝的动态过程中尚未涉及这些方面。
