Electrowetting-on-Dielectric Device Controlled by Embedded Undulating Electrode for Liquid Transport.

Area of Science:

• Physics
• Materials Science
• Microfluidics

Background:

• Electrowetting-on-dielectric (EWOD) devices offer precise control over liquid behavior.
• Existing EWOD architectures face limitations in design flexibility and driving complexity.

Purpose of the Study:

• To develop a new EWOD device architecture for efficient liquid droplet transport.
• To investigate the use of spatial electric field modulation for droplet manipulation.

Main Methods:

• Fabrication of an EWOD device with an embedded undulating electrode on dielectric microstructures.
• Generation of a spatially varying lateral electric field through electrode design.
• Modulation of electric field amplitude to create surface wettability gradients.
• Observation and measurement of water droplet contact angle changes with electric field strength.

Main Results:

• The contact angle of water droplets decreased from 120 to 50 degrees with increasing electric field strength.
• Liquid droplet transport was achieved by spatially modulating the electric field, not temporally.
• The device demonstrated a tunable electric field capable of creating wettability gradients.

Conclusions:

• The novel EWOD architecture enables precise liquid droplet transport via spatial electric field modulation.
• The design offers flexibility, a simple driving scheme, and high positional accuracy for liquid manipulation.
• This approach advances microfluidic control for various scientific and technological applications.