Superhydrophobic ZnO for EWOD Digital Microfluidic Device for Application in Micro Total Analysis System (μ-TAS)

Abstract

In this paper, we present a nanostructured ZnO based superhydrophobic high dielectric constant (K) Composite dielectric for EWOD digital microfluidic device for application in μ-TAS. Two fabrication methods of nannosturctured ZnO superhydrophobic surface are studied. Through electrochemical deposition, a nanostructured ZnO film with a dielectric constant of 6.21 and a maximum contact angle of 158.9° is achieved. To prevent electrical leakage, a high dielectric constant barrier is combined with hydrothermal synthesis of ZnO nanorods. The contact angle reaches 164.8° on the composite surface with a contact angle hysteresis of 11.3^°. Enhancement of optical signal detected on the superhydrophobic layer is demonstrated. Using such superhydrophobic high k composite material in EWOD digital microfluidics for application in μ-TAS is proposed and has shown its potential feasibility.

Keywords:

• Superhydrophobic surface
• nano-ZnO
• EWOD
• high k composite dielectric

Acknowledgements

This work was supported by China’s Mega-projects of Science Research for the 11th Five-Year Plan (Grant No. 2008ZX100 03 003) and the National Science Foundation of China (Grant No. 60876085 and No. 61176110).