Department of Chemical and Biomolecular Engineering, The University of Melbourne, Parkville, VIC 3010, Australia.
Langmuir. 2012 Mar 6;28(9):4259-66. doi: 10.1021/la204753y. Epub 2012 Feb 22.
A systematic study of collisions between surfactant-free organic drops in aqueous electrolyte solutions reveals the threshold at which continuum models provide a complete description of thin-film interactions. For collision velocities above ~1 μm/s, continuum models of hydrodynamics and surface forces provide a complete description of the interaction, despite the absence of surfactant. This includes accurate prediction of coalescence at high salt concentration (500 mM). In electrolyte solutions at intermediate salt concentration (50 mM), drop-drop collisions at lower velocity (<1 μm) or extended time of forced drop-drop interaction exhibit a strong pull-off force of systematically varying magnitude. The observations have implications on the effects of ion-specificity and time-dependence in drop-drop interactions where kinetic stability is marginal.
对无表面活性剂的有机液滴在水基电解质溶液中碰撞的系统研究揭示了连续体模型能够完全描述薄膜相互作用的阈值。对于大于约 1 μm/s 的碰撞速度，尽管没有表面活性剂，流体动力学和表面力的连续体模型仍能完全描述相互作用，包括在高盐浓度（500 mM）下准确预测聚并。在中间盐浓度（50 mM）的电解质溶液中，在较低速度（<1 μm/s）或强制液滴相互作用的延长时间下，液滴-液滴碰撞表现出系统变化幅度的强脱拉力。这些观察结果对于在动力学稳定性很边缘的情况下具有离子特异性和时间依赖性的液滴-液滴相互作用的影响具有重要意义。
