The Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP, United Kingdom.
Phys Rev Lett. 2013 Jun 28;110(26):264502. doi: 10.1103/PhysRevLett.110.264502.
We report on the onset of fluid entrainment when a contact line is forced to advance over a dry solid of arbitrary wettability. We show that entrainment occurs at a critical advancing speed beyond which the balance between capillary, viscous, and contact-line forces sustaining the shape of the interface is no longer satisfied. Wetting couples to the hydrodynamics by setting both the morphology of the interface at small scales and the viscous friction of the front. We find that the critical deformation that the interface can sustain is controlled by the friction at the contact line and the viscosity contrast between the displacing and displaced fluids, leading to a rich variety of wetting-entrainment regimes. We discuss the potential use of our theory to measure contact-line forces using atomic force microscopy and to study entrainment under microfluidic conditions exploiting colloid-polymer fluids of ultralow surface tension.
我们报告了当接触线被迫在任意润湿性的干燥固体上前进时，流体夹带的开始。我们表明，夹带发生在一个临界推进速度之上，超过这个速度，维持界面形状的毛细、粘性和接触线力之间的平衡就不再满足。润湿通过设定界面在小尺度上的形态和前缘的粘性摩擦来与流体动力学耦合。我们发现，界面能够承受的临界变形受接触线处的摩擦力和置换与被置换流体之间的粘度对比的控制，导致了丰富多样的润湿夹带状态。我们讨论了我们的理论在使用原子力显微镜测量接触线力和在利用超低表面张力的胶体-聚合物流体的微流条件下研究夹带方面的潜在应用。
