Electrowetting of the blood droplet on the hydrophobic film of the EWOD chips.

Electrowetting-on-dielectric (EWOD) is a new method for handling droplets on the microfluidic chips. A most promising application for EWOD chips is the clinical diagnostics on human physiological fluids. This paper uses pure blood of rabbit as the experimental sample to test the wettability of the fluorocarbon polymer (p-C:F) hydrophobic layer of the EWOD chips. The contact angle variation of the blood droplet is observed, which provides the possibility of pure blood driven on the chips of p-C:F film. Forty multiple magnification images of the blood droplet are acquired by delicate experiments and the contact angles are calculated based on image processing technology. The electrowetting of the blood droplets on the EWOD chips is analyzed and the experimental results are in good agreement with the theoretical calculation.