Fetzer Renate, Ramiasa Melanie, Ralston John
Ian Wark Research Institute, University of South Australia, Adelaide, SA 5095, Australia.
Langmuir. 2009 Jul 21;25(14):8069-74. doi: 10.1021/la900584s.
Capillary driven liquid-liquid displacement in a system with two immiscible liquids of comparable viscosity was investigated by means of optical high speed video microscopy. For the first time, the impact of substrate wettability on contact line dynamics in liquid-liquid systems was studied. On all substrates, qualitatively different dynamics, in two distinct velocity regimes, were found. Hydrodynamic models apply to the fast stage of initial spreading, while nonhydrodynamic dissipation dominates contact line motion in a final stage at low speed, where the molecular kinetic theory (MKT) successfully captured the dynamics. The MKT model parameter values showed no systematic dependence on substrate wettability. This unexpected result is interpreted in terms of local contact line pinning.
通过光学高速视频显微镜研究了在具有两种粘度相当的不混溶液体的系统中毛细管驱动的液-液置换。首次研究了基底润湿性对液-液系统中接触线动力学的影响。在所有基底上，发现了两种不同速度 regime 下性质不同的动力学。流体动力学模型适用于初始铺展的快速阶段，而非流体动力学耗散在低速的最终阶段主导接触线运动，在该阶段分子动力学理论（MKT）成功捕捉到了动力学。MKT 模型参数值未显示出对基底润湿性的系统依赖性。这一意外结果根据局部接触线钉扎进行了解释。
