Research and Development of ElectroWetting Micro Viscometer
Date Issued
2006
Date
2006
Author(s)
Lin, Yan-You
DOI
en-US
Abstract
Nowadays, the bio- medical analysis requires fewer amount of sample, and the analysis device should be scaled down as well. The traditional viscometers utilize mechanical forces from the motors and electro- magnetic forces in the channel mostly. However, in this study, the micro viscometer uses Electrowetting on Dielectric (EWOD) to change the surface tension between liquid and channel and uses liquid velocity gradient in the channel to find the viscosity coefficient with the volume of 10 μl.
In this paper, we use electrowetting on dielectric (EWOD) to drive the liquids. There are four different sizes of electrode on a 2.3 cm× 2.3 cm chip, and two kinds of channel to measure the velocity gradient for the viscosity coefficient. The device is fabricated by means of micro electro mechanic system (MEMS) technology. The dielectric layer of EWOD is a high dielectric constant material — BST (Ba0.7Sr0.3TiO3), which ranges from 120 to 200 therefore reducing the required applied voltage, with hydrophobic polymer (Teflon® AF) coated on surface. Our simulation results indicate the feasibility of this device for various solutions with viscosity coefficient in the range of 0.5×10-3 ~ 2×10-3 Pa-s, which corresponds to the velocity ranging from 5 to 140 mm/sec by applying 20 volts to the devices. The experiment results show that saline can be pulled in linear channels by applying a voltage of 15 volts with a velocity 0.3167~0.66 mm/s and viscosity coefficient 40.26 Pa-s.
Subjects
電濕潤
黏滯計
微機電
微流道
Electrowetting
viscometer
MEMS
microfluid channel
Type
thesis
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