Fu Li, Merabia Samy, Joly Laurent
Univ Lyon, Université Claude Bernard Lyon 1, CNRS, Institut Lumière Matière, F-69622 Villeurbanne, France.
Phys Rev Lett. 2017 Nov 24;119(21):214501. doi: 10.1103/PhysRevLett.119.214501. Epub 2017 Nov 20.
Thermo-osmotic and related thermophoretic phenomena can be found in many situations from biology to colloid science, but the underlying molecular mechanisms remain largely unexplored. Using molecular dynamics simulations, we measure the thermo-osmosis coefficient by both mechanocaloric and thermo-osmotic routes, for different solid-liquid interfacial energies. The simulations reveal, in particular, the crucial role of nanoscale interfacial hydrodynamics. For nonwetting surfaces, thermo-osmotic transport is largely amplified by hydrodynamic slip at the interface. For wetting surfaces, the position of the hydrodynamic shear plane plays a key role in determining the amplitude and sign of the thermo-osmosis coefficient. Finally, we measure a giant thermo-osmotic response of the water-graphene interface, which we relate to the very low interfacial friction displayed by this system. These results open new perspectives for the design of efficient functional interfaces for, e.g., waste-heat harvesting.
从生物学至胶体科学的诸多情形中均可发现热渗透及相关的热泳现象，但其潜在的分子机制在很大程度上仍未得到探索。通过分子动力学模拟，我们针对不同的固液界面能，采用机械热效应和热渗透两种途径测量了热渗透系数。模拟结果特别揭示了纳米尺度界面流体动力学的关键作用。对于非润湿性表面，界面处的流体动力滑移在很大程度上放大了热渗透输运。对于润湿性表面，流体动力剪切面的位置在确定热渗透系数的幅度和符号方面起着关键作用。最后，我们测量了水 - 石墨烯界面巨大的热渗透响应，这与该系统所表现出的极低界面摩擦力有关。这些结果为例如废热收集等高效功能界面的设计开辟了新的前景。
