Direct AFM measurements of morphology and interaction force at solid-liquid interfaces between DTAC/CTAC and mica

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• 作者：Zhen Xie 谢珍 ; Hao Jiang 蒋昊 ; Zhong-cheng Sun 孙忠诚…
• 关键词：Key wordsadsorption ; cationic surfactants ; interaction force ; atomic force microscopy
• 刊名：Journal of Central South University
• 出版年：2016
• 出版时间：September 2016
• 年：2016
• 卷：23
• 期：9
• 页码：2182-2190
• 全文大小：2,402 KB
• 刊物类别：Engineering
• 刊物主题：Engineering, general
  Metallic Materials
  Chinese Library of Science
  
• 出版者：Central South University, co-published with Springer
• ISSN：2227-5223
• 卷排序：23

文摘

The adsorption of dedecyltrimethylammoium chloride (DTAC) and hexadecyltrimethylammoium chloride (CTAC) on muscovite mica substrates was examined using atomic force microscopy (AFM). Adsorption morphology images and interaction forces of cationic surfactants at solid-solution interfaces were measured in tapping mode and PicoForce mode, respectively. The images demonstrated that the adsorbed structure was varied by a variety of surfactant concentrations. The adsorbed layer on mica was monolayer at first, and then became bilayer. A striped adsorbed structure was observed in a higher concentration of CTAC, which could not be found in any other concentrations of DTAC. For force measurements, the repulsive force was exponentially decreasing with the concentration increasing till a net attractive force appeared. A largest attractive force could be observed at a certain concentration, which was close to the point of charge neutralization. The results also showed a significant impact of hydrocarbon chain length on adsorption. An adsorption simulation was established to give a clear understanding of the interaction between cationic surfactants and mica.