Fluctuations at nanoscales : transport and fluctuating surfaces

As Feynman remarked, " Everything that living things do can be understood in terms of the jigglings and wigglings of atoms ". At nanometric scales, fluctuations become predominant. How do they affect transport, and can we take advantage of them for sieving functions, for example ? This lecture will explore how fluctuations modify nanofluidic transport, from different points of view. This will lead us to introduce various theoretical tools that will enable us to assess the impact of thermal fluctuations on fluid transport. But we'll also look at how fluctuations in the walls themselves can modify diffusion within them and flows. Finally, we'll look at how fluctuations in pore size can affect transport and sieving, notably via stochastic resonance-type effects. This type of mechanism has recently been invoked to explain isotopic separation effects. These approaches reveal an unsuspected wealth of behaviours that suggest ways of taking advantage of fluctuations to overcome the constraints imposed by the trade-off between selectivity and permeability.