Investigation on the effects of surface microstructures on static contact angles and surface adhesion phenomena

• Main Authors: I-Hong Shih, 施昱宏
• Other Authors: Jenn-Der Lin
• Format: Others
• Language: zh-TW
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/66160388054690975735

碩士 === 國立交通大學 === 機械工程系所 === 93 === This study first purposes to investigate the contact angles formed at conditions of various surface microstructures. MEMS fabricated microstructure is performed using the silicon wafer inserts with various dimensions, shapes, and arrangement of hydrophobic materials. The sessile-drop technique is used for contact angle measurements. Experimental examinations of the relationship between contact angle and varieties of solid microstructure roughness are performed. In the second part of the study, we examine the effects of various surface microstructure on the surface adhesion phenomena. MEMS fabricated microstructure on the wafer is performed using previous already designed microstructure and pipets used for dripping droplets on the designed surfaces in association with a centrifuge for providing an additional force source. After droplets pass through the surfaces, the residual fluid and distribution are investigated and the results are compared to the former part. Experimental results show that the droplets tend to immerse in the gap between the microstructures if the gap becomes wider and wider and droplets can not fall into the gap between the higher microstructures. The static contact angle for cross-type microstructures is bigger than the square-type microstructures. Experimental results for surface adhesion phenomena show that the main and minor droplet immerse in the gap between the striped microstructures regardless their contact angle, but the droplet for mix-type microstructures does not show this phenomena.