Transient molecular diffusion in microfluidic channels: Modeling and experimental verification of the results
| Autor: | Ali Hooshyar Zare, Faramarz Hossein-Babaei, Vahid Ghafarinia |
|---|---|
| Rok vydání: | 2016 |
| Předmět: |
Coupling
Molecular diffusion Microchannel Chemistry 010401 analytical chemistry Microfluidics Metals and Alloys Analytical chemistry 02 engineering and technology Mechanics 021001 nanoscience & nanotechnology Condensed Matter Physics 01 natural sciences Isothermal process 0104 chemical sciences Surfaces Coatings and Films Electronic Optical and Magnetic Materials Physics::Fluid Dynamics Materials Chemistry Fluid dynamics Boundary value problem Transient (oscillation) Electrical and Electronic Engineering 0210 nano-technology Instrumentation |
| Zdroj: | Sensors and Actuators B: Chemical. 233:646-653 |
| ISSN: | 0925-4005 |
| Popis: | Almost all microfluidic devices operate at non-equilibrium transient conditions. Quantitative predictions regarding fluid flow within the components of such devices at the assumed conditions are a prerequisite for their systematic design. Here, we present a mathematical model for the transient dynamics of a target molecule (TM) diffusing along a microfluidic channel driven by a time-varying concentration gradient, and experimentally verify its predictions on a number of case studies. The model is the outcome of coupling the free molecular diffusion equation and Langmuir surface adsorption isotherm, both of which hold the specific geometrical and operational features of the microfluidic system at isothermal and isobar conditions. The TM flux fluctuations, caused by a sudden change in the imposed boundary conditions, are predicted to be highly uneven along the microchannel for a long time after the event. In complicated cases, such as a pulse train TM concentration modulation at the inlet of a background gas-filled microfluidic channel, the model correctly predicts the experimental results in both “diffuse-in” and “diffuse-out” conditions. |
| Databáze: | OpenAIRE |
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