Laboratory of Surface and Interfacial Physics, University of Mons, Parc Initialis, Avenue Copernic, MateriaNova, 7000 Mons, Belgium.
Langmuir. 2011 Aug 16;27(16):9866-72. doi: 10.1021/la200439e. Epub 2011 Jul 19.
We present new data obtained from the spreading of a series of oil droplets, on top of a hydrophobic grafted silicon substrate, in air and immersed in water. We follow the contact angle and radius dynamics of hexane, dodecane, hexadecane, dibutyl phthalate, and squalane from the first milliseconds to approximately 1 s. Analysis of the images allows us to make several hundred contact angle and droplet radius measurements with great accuracy. The G-Dyna (Seveno et al. Langmuir 2010, 25, 13034) software is then used to fit the data with one of the wetting theories, the molecular-kinetic theory (MKT) (Blake et al. J. Colloid Interface Sci.1969, 30, 421), which takes into account the dissipation at the three-phase zone at the contact line. This theory allows us to extract the coefficient of friction of the contact line, which expresses the relationship between the driving force, that is, the unbalanced Young force, and the contact-line velocity V. It is first shown that the MKT is appropriate to describe the experimental data and then that the contact-line friction is a linear function of the viscosity as theoretically predicted. This is checked for oil-air and oil-water systems. A linear relation between the contact-line friction measured in oil-water systems and the contact-line frictions of the parent single liquid system seems plausible. To the best of our knowledge, this is the first trial to establish a link between the dynamics of wetting in liquid-liquid and in liquid-air systems.
我们呈现了在空气和水中传播一系列油滴的新数据，这些油滴位于疏水接枝硅衬底上。我们跟踪了正己烷、十二烷、十六烷、邻苯二甲酸二丁酯和角鲨烷的接触角和半径动力学，从最初的几毫秒到大约 1 秒。对图像的分析使我们能够以非常高的精度进行数百次接触角和液滴半径测量。然后，使用 G-Dyna（Seveno 等人，Langmuir 2010，25，13034）软件，通过将数据拟合到润湿理论之一——分子动力学理论（MKT）（Blake 等人，J. Colloid Interface Sci.1969，30，421）来分析数据，该理论考虑了三相区在接触线处的耗散。该理论使我们能够提取接触线的摩擦系数，该系数表达了驱动力（即不平衡杨氏力）与接触线速度 V 之间的关系。首先表明 MKT 适合描述实验数据，然后表明接触线摩擦是粘性的线性函数，这与理论预测一致。这在油-空气和油-水系统中得到了验证。在油水系统中测量的接触线摩擦与母液单体制备系统的接触线摩擦之间存在线性关系，这似乎是合理的。据我们所知，这是首次尝试在液-液和液-气系统的润湿动力学之间建立联系。
