| Summary: | 碩士 === 國立臺灣大學 === 機械工程學研究所 === 97 === The present study employed a laser interference design to fabricate one- and two-dimensional periodical nanopatterns. Combining the conventional lithography, large areas of hierarchical structure can be achieved in simple processes.
The pitch of nanopattern was dependent on both the incident wavelength and interference angle, and hence, different geometrical sizes of regular nanopatterns were easily fabricated by altering interference angle. The minimum feature size for nanopattern was 100 nm. Here, this study reported the variable wetting properties, including hydrophilicity, hydrophobicity and anisotropic behavior of water droplets, on different morphologies of nanopatterns with controlled dimensions.
According to this study, one-dimensional nanowires displayed strongly anisotropic wetting behavior with feature size from 200 nm to 1500 nm. Moreover, the surfaces of nanowires were manipulated from hydrophilic to hydrophobic by coating a layer of HMDS. For two-dimensional nanopillar array, the contact angles on 2D nanopillars increased with decreasing feature sizes of nanopatterns. The contact angle up to 120° while feature size of nanopillars down to 200 nm, and the critical size for transition from hydrophobic to hydrophilic is 500 nm. As for hierarchical structures, they were successfully completed on the glass substrate, like the surfaces of lotus leaves. However, these hierarchical structures did not show the extreme wetting properties. Finally, this study supported that surfaces with wetting properties have the potential application in microfluidic devices.
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