Grant: Discovery Grants Program - Individual

Microfluidics, by name, studies the behaviors of fluids of very small volumes. Applications of microfluidics can be found in biotech lab-on-a-chips for biochemical analysis, fuel cells for clean and efficient energy, and micro heat exchangers for electronics. Recently, liquid droplets, which can function as the smallest reactors in chemical and biochemical reactions, are considered as the next generation microfluidic technology, or the so-called digital microfluidics. In such systems for biological and biochemical analysis, interfacial tension and surface wettability are usually employed for flow metering, activation, and control. Due to the high surface-area-to-volume ratio, microscopic solid-fluid interactions and related interfacial phenomena have to be considered carefully in digital microfluidics. However, quantitative information is still inadequate and hence continues to hinder relevant engineering applications. The proposed program aims to advance our knowledge in the relationship between surface properties and droplet behaviors through computational investigations. In this program, we will develop a computational framework to simulate multiphase flows (droplets, bubbles, free surface flows, etc.) with various surface effects considered. The lattice Boltzmann method, a new simulation technology developed from statistical physics, will be employed for its flexibility in dealing with multiphase fluids and for its capability to incorporate microscopic interactions. Meanwhile, different activation and control technologies in digital microfluidics, including centrifugal pumping, electrowetting and thermocapillary, will be investigated to explore precise control and manipulation of droplet behaviors.