Setu Siti Aminah, Dullens Roel P A, Hernández-Machado Aurora, Pagonabarraga Ignacio, Aarts Dirk G A L, Ledesma-Aguilar Rodrigo
1] Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK [2] Department of Chemistry, Faculty of Science, Universiti Teknologi Malaysia, Johor Bahru, Johor 81310, Malaysia.
Department of Chemistry, Physical and Theoretical Chemistry Laboratory, University of Oxford, South Parks Road, Oxford OX1 3QZ, UK.
Nat Commun. 2015 Jun 15;6:7297. doi: 10.1038/ncomms8297.
Understanding fluid dynamics under extreme confinement, where device and intrinsic fluid length scales become comparable, is essential to successfully develop the coming generations of fluidic devices. Here we report measurements of advancing fluid fronts in such a regime, which we dub superconfinement. We find that the strong coupling between contact-line friction and geometric confinement gives rise to a new stability regime where the maximum speed for a stable moving front exhibits a distinctive response to changes in the bounding geometry. Unstable fronts develop into drop-emitting jets controlled by thermal fluctuations. Numerical simulations reveal that the dynamics in superconfined systems is dominated by interfacial forces. Henceforth, we present a theory that quantifies our experiments in terms of the relevant interfacial length scale, which in our system is the intrinsic contact-line slip length. Our findings show that length-scale overlap can be used as a new fluid-control mechanism in strongly confined systems.
理解在极端受限条件下的流体动力学至关重要，此时器件和固有流体长度尺度变得相当，这对于成功开发下一代流体器件至关重要。在此，我们报告了在这种我们称之为超受限的 regime 中推进流体前沿的测量结果。我们发现接触线摩擦与几何限制之间的强耦合产生了一种新的稳定 regime，其中稳定移动前沿的最大速度对边界几何形状的变化表现出独特的响应。不稳定前沿发展为由热涨落控制的液滴发射射流。数值模拟表明，超受限系统中的动力学由界面力主导。此后，我们提出了一种理论，该理论根据相关界面长度尺度对我们的实验进行量化，在我们的系统中，该长度尺度是固有接触线滑移长度。我们的研究结果表明，长度尺度重叠可作为强受限系统中的一种新的流体控制机制。
