Enhanced Wettability of an SU-8 Photoresist through a Photografting Procedure for Bioanalytical Device Applications
In this work, we detail a method whereby a polymeric hydrogel layer is grafted to negative tone photoresist SU-8 in order to improve its wettability. A photoinitiator is first immobilized on freshly prepared SU-8 samples, acting as the starting point for various surface modification strategies. Grafting of a 2-hydroxyethylmethacrylate-based hydrogel from the SU-8 surface resulted in the reduction of the static contact angle of a water droplet from 79 ± 1◦ to 36 ± 1◦, while addition of a poly(ethylene glycol)-rich hydrogel layer resulted in further improvement (8 ± 1◦). Wettability is greatly enhanced after 30 min of polymerization, with a continued but more gradual decrease in contact angle up to approximately 50 min. Hydrogel formation is triggered by exposure to UV irradiation, allowing for the formation of photopatterned structures using existing photolithographic techniques.
Z. Gao et al., "Enhanced Wettability of an SU-8 Photoresist through a Photografting Procedure for Bioanalytical Device Applications," Journal of Micromechanics and Microengineering, Institute of Physics - IOP Publishing, Apr 2008.
The definitive version is available at http://dx.doi.org/10.1088/0960-1317/18/4/045013
Electrical and Computer Engineering
Chemical and Biochemical Engineering
Intelligent System Center, Missouri, University of Science and Technology
National Institute of Environmental Health
National Science Foundation (U.S.)
Keywords and Phrases
Bioanalytical Device; Hydrogel Layer; Photografting; Photoinitiator; Photoresist; Wettability
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