Clay particle charging in apolar media
Clay particle charging in apolar media
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DOI：
10.1016/j.clay.2018.04.016
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发表时间：
2018-09
影响因子：
5.6
通讯作者：
Benjamin S Ponto;J. Berg
中科院分区：
文献类型：
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作者：
Benjamin S Ponto;J. Berg
电泳显示器的进步（例如，AmazonKindle ®）和新的高质量打印技术（例如，HP靛蓝®）通过控制和了解非极性介质中颗粒带电的能力而成为可能。虽然以前的工作已经研究了酸碱充电机制的氧化物和类似的颗粒，只有一个充电机制在水中，本研究的目的是确定是否和如何粘土颗粒，其中有两个已知的水充电机制，在非极性介质中充电。在非极性介质中，采用不同表面活性剂对高岭石和蒙脱石的表面荷电特性和机理进行了表征。结果发现，粘土颗粒的充电行为作为表面活性剂浓度的函数模仿预期的趋势，以前研究的氧化物，可以充电，只有通过酸碱机制。此外，通过将粘土颗粒的边缘基团的零电荷点（边缘PZC）或零净质子电荷点（PZNPC）与表面活性剂的经验有效pH（pHEff）进行比较，可以预测颗粒电荷的极性。除了颗粒带电之外，还表明表面活性剂还改善了对颗粒聚集和沉降的稳定性。
Advancements in electrophoretic displays (e.g., the Amazon Kindle®) and new high-quality printing technologies (e.g., HP Indigo®) have been made possible by the ability to control and understand particle charging in apolar media. While previous work has investigated the acid-base charging mechanisms of oxides and similar particles which have only one charging mechanism in water, the purpose of this study was to determine if and how clay particles, which have two known aqueous charging mechanisms, charge in apolar media. Characterization of kaolinite and montmorillonite surface charging properties and mechanisms were conducted in apolar media utilizing different surfactants. It was found that clay particle charging behavior as a function of surfactant concentration mimicked the expected trend of previously studied oxides, which can charge only via an acid-base mechanism. Furthermore, by comparing the point of zero charge of the edge groups (edge PZC) or the point of zero net proton charge (PZNPC) of the clay particle to the empirical effective pH (pHEff) of the surfactant, the polarity of the particle charge can be predicted. In addition to particle charging, it was shown that the surfactants also improve the stability against aggregation and settling of the particles.