A novel micromixer based on the alternating current-flow field effect transistor.

Area of Science:

• Microfluidics
• Electrokinetics
• Nanotechnology

Background:

• Induced-charge electroosmosis (ICEO) is a key phenomenon for microfluidic pumping and mixing.
• Existing ICEO methods often require complex structures or high energy consumption.
• Developing efficient and simple microfluidic mixers remains a significant challenge.

Purpose of the Study:

• To propose and investigate a novel microfluidic mixer based on fixed-potential ICEO flow around a floating electrode.
• To demonstrate the application of an AC-flow FET (AC-FFET) concept for generating asymmetric ICEO flow for mixing.
• To evaluate the mixing efficiency and performance enhancement strategies for the proposed AC-FFET micromixer.

Main Methods:

• Fabrication of a microfluidic device with a tandem electrode configuration on glass substrates.
• Utilizing a floating electrode as a gate to control ICEO flow, analogous to a field-effect transistor (FET).
• Conducting mixing experiments and comparing results with simulations to validate performance.

Main Results:

• The AC-FFET device demonstrated efficient microfluidic mixing capabilities.
• Asymmetric vortexes were generated using the tandem electrode configuration, leading to effective mixing.
• Mixing performance was enhanced by optimizing the phase difference between electrodes and using square wave signals.

Conclusions:

• The AC-FFET offers a simple and effective solution for microfluidic mixing.
• The device exhibits low-energy consumption and can be manufactured using cost-effective processes.
• This approach provides a promising alternative for addressing mixing challenges in microfluidic systems.