A Study of Contact Angle on Micro-Patterned Substrates and Preliminary Development of MEMS for Droplet Control
Date Issued
2005
Date
2005
Author(s)
Shen, Si-Kai
DOI
zh-TW
Abstract
In this thesis, we develop a reversible and bi-stable droplet-controlling system (RBDCS) to control the contact angle. The device is fabricated by MEMS. The method focuses on changing the surface geometry on which the contact angle can vary mechanically. In order to investigate the relationship between the surface roughness and the contact angle, we fabricate micro-hole and micro-pillar surfaces. The measurements of the contact angle show a very good agreement in comparing with those predicted by Cassie’s formula.
The development of the RBDCS aims to combine those theories from electrostatic microactuator and contact angle. The device is fabricated in 25 processes with 5 masks by surface micromachining. The design of RBDCS is divided into two parts. One is the design of the surface, which takes advantage of the above-mentioned study of contact angle on micro-patterned substrates, but is restricted to the design of the microactuator. The other is the design of the microactuator which is restricted to both the rules about RBDCS and the manufacture processes. The design is also analyzed by FEM and the applied voltage is solved by the electrostatic theory.
The RBDCS is still under development. It cannot be used to measure the real-time contact angle of droplets. Nevertheless we can statically measure the contact angle of droplets on the surface component of the RBDCS and investigate the structural behaviors. The results indicate the difference in contact angle between the theoretical value and the practical value is fifteen, and the microactuator is strong enough to resist mechanical deformation.
Subjects
微機電系統
液滴接觸角
表面改質法
靜電式微致動器
微滴操控技術
MEMS
contact angle
surface modification
electrostatic actuator
droplet control
Type
thesis
File(s)![Thumbnail Image]()
Loading...
Name
ntu-94-R92521606-1.pdf
Size
23.31 KB
Format
Adobe PDF
Checksum
(MD5):9396a95b59972bc8871e00f463b57636