On-chip desalination and energy harvesting using nanochannels
Fabricated microchannel-nanochannel systems share a number of similarities with the older and more well-known field of ion-selective membranes, but it may be the differences which have the most applicative and fundamental scientific importance. In contrast to the highly tortuous, multi-pore and almost ideal ion permselective membrane, the straight fabricated nanochannel exhibits discernible electroosmotic permeability, non-ideal permselectivity and geometrical heterogeneity. Additionally, in contrast to studies using bulk nanoporous membranes, the pseudo two-dimensional microfabricated nanoslot enables direct imaging of the polarized layers, as well as almost absolute control over geometry and surface properties. Understanding the various effects occurring in these different systems is of particular interest for applications such as pre-concentration of analytes, electrodialysis, electroconvective mixing, and biomolecular detection.