Bio-Fluid Transport Models Through Nano and Micro-Fluidic Components

摘要

This project was a combined fabrication, experimental, and modeling effort to predict transport properties of micro and nanochannels. In this work, the governing equations for electrokinetic flow are solved for not only monovalent binary electrolytes, but also multi-component electrolytic systems containing multivalent ion species. For channel-reservoir systems, the wall concentrations of different ion species are obtained using electrochemical equilibrium consideration. For channel materials with known surface charge density, the results are truly predictive, i.e. there are no assumable constants in the model. The results agree very well with the experimental data from four separate sources at over thirty five operating conditions. This implies that the model is effective for channel height varying from less than ten nanometers to several micrometers. The experimental effort demonstrated that the novel nano-particle image velocimetry (nPIV) technique could measure velocity fields within 250 nm of the wall in steady electroosmotic flow with good accuracy. The nPIV data were in excellent agreement with the model predictions for monovalent electrolyte solutions, and were further validated by independent experimental measurements. This effort culminated in what we believe to be the first experimental probe inside the electric double layer in electroosmotic flow of an aqueous electrolyte.