Light-driven 3D droplet manipulation on flexible optoelectrowetting devices fabricated by a simple spin-coating...

Area of Science:

• Materials Science
• Microfluidics
• Optoelectronics

Background:

• Conventional 3D electrowetting-on-dielectric (EWOD) devices are complex and expensive.
• Existing optoelectrowetting (OEW) devices require high-temperature fabrication incompatible with flexible substrates.
• Light-driven 3D droplet manipulation on flexible surfaces has not been demonstrated.

Purpose of the Study:

• To present a flexible single-sided continuous optoelectrowetting (SCOEW) device.
• To enable light-driven 3D droplet manipulation on flexible substrates.
• To overcome the thermal incompatibility of traditional OEW materials with flexible substrates.

Main Methods:

• Fabrication of SCOEW devices using a low-cost spin-coating method.
• Utilized a polymer-based photoconductive material, titanium oxide phthalocyanine (TiOPc).
• Analytical studies on light patterns' effects on contact angles and EWOD forces.

Main Results:

• Successfully fabricated flexible SCOEW devices via TiOPc spin-coating.
• Demonstrated light-driven 3D droplet manipulations (transportation, merging, splitting).
• Manipulations were performed on diverse 3D terrains including inclined, vertical, upside-down, and curved surfaces.

Conclusions:

• The flexible SCOEW technology offers a simpler, more flexible, and functional alternative to conventional EWOD and OEW devices.
• Enables optical droplet manipulation on 3D featureless surfaces.
• Overcomes substrate compatibility issues using polymer-based photoconductive materials.