Controlling ion transport through nanopores : introducing realistic model parameters

Abstract

Synthetic bioinspired nanopores can be applied as nanodevices for sensing, filtering and ionic gating.With the connection of these individual devices complex nanofluidic circuits can be designed that can be useful to create lab-on-a-chip devices. Thus, the study of the individual devices, such as nanosensors, nanofluidic diodes and nanofluidic transistors, is indispensable. The behaviour of these devices and the mechanisms behind it however, only can be accessed through simulations. In this thesis two simulation methods, the Nernst-Planck equation coupled to Local Equilibrium Monte Carlo (NP+LEMC) method and the Poisson-Nernst-Planck (PNP) theory, are compared based on the study of the behaviour of a pH-gated nanofluidic transistor. To relate to experiments, realistic model parameters will be introduced for the pH-gating and the electrolyte models. The device behaviour, assessed through concentration profiles, and scaling effect will be examined using these new model parameters and appropriate scaling coefficients with respect for the different computational methods. Furthermore, the importance of the proper treatment of ionic correlations will be presented through the comparison of the results obtained by the two simulation methods.