Abstract

Nanotechnology is not just conventional technology scaled down to the nano-scale. The reason is that processes that are relatively unimportant on macroscopic scales may become dominant on the nano-scale. Case in point are phoretic flows: the movement of fluids under the influence of gradients of thermodynamic quantities such as temperature or chemical potential. On a macroscopic scale, the application of a pressure gradient or a body force is the most efficient way to move fluid through a tube. The resulting flux is proportional to the fourth power of the tube diameter. However, on a sub-micron scale, phoretic flows tend to become important because the resulting volumetric flow rates scale as the square of the tube diameter. Hence, for many problems, be they technological (e.g. nano-fluidics) or natural (e.g. fluid flow through porous networks or gels), it is becoming increasingly important to be able to model phoretic flows. It turns out that, whilst the local continuum description of phoresis is straightforward, there are real problems with a fully microscopic approach that is needed in predictive molecular simulations. In my talk, I will discuss different approach to computing phoretic flows and show what works, and more interestingly, what fails.