The flow of ions and water through viscoelastic, nanoscopic domains forms the basis for many processes in biological materials. Surprisingly, such systems have rarely been investigated in a theoretical manner for nanofluidic transport in artificial channels of technological applications such as energy harvesting, water desalination or DNA purification.

This talk explores the nonlinear coupling between wall deformation and quasi 1-D electrokinetic transport in a nanochannel with charged walls. Within the framework of nonequilibrium thermodynamics, formulae are derived for the electrokinetic transport parameters in terms of Onsager phenomenological coefficients and, subsequently, for energy conversion efficiencies. Results confirm that Onsager’s reciprocity principle holds for rigid channels but breaks down in the 1-D formulation when the channel is deformed due to the introduction of a fictitious diffusion term of counter-ions. Furthermore, the model predicts a reduced efficiency of electrokinetic energy harvesting for channels with soft, deformable walls.

The presentation will conclude with a brief discussion about how this research relates to electroactuators and polymer electrolyte membranes.

This is joint work with M. Matse, M. Eikerling and J. Fuhrmann. This work is supported by a NSERC Discovery Grant (P.B.).