Keywords
3D printing, microfluidic device, droplet formation, surface energy, post-polymerization processing, wetting
Abstract
Microfluidic devices (MFDs) printed in 3-D geometry using digital light projection to polymerize monomers often have surfaces that are not as hydrophobic as MFDs made from polydimethylsiloxane. Droplet microfluidics in these types of devices are subject to droplet adhesion and aqueous spreading on less hydrophobic MFD surfaces. We have developed a post-processing technique using hydrophobic monomers that renders the surfaces of these devices much more hydrophobic. The technique is fast and easy, and involves flowing monomer without initiator into the channels and then exposing the entire device to UV light that generates radicals from the initiator molecules remaining in the original 3-D polymerization. After treatment the channels can be cleared and the surface is more hydrophobic, as evidenced by higher contact angles with aqueous droplets. We hypothesize that radicals generated near the previously printed surfaces initiate polymerization of the hydrophobic monomers on the surfaces without bulk polymerization extending into the channels. The most hydrophobic surfaces were produced by treatment with an alkyl acrylate and a fluorinated acrylate. This technique could be used for surface treatment with other types of monomers to impart unique characteristics to channels in MFDs.
Original Publication Citation
Warr, C.A., Crawford, N.G., Nordin, G.P., Pitt, W.G.*, “Surface Modification of 3D Printed Microfluidic Devices for Controlled Wetting in Two-Phase Flow”, Micromachines, 14(1) 1-10 (2023) https://doi.org/10.3390/mi14010006. https://www.mdpi.com/2072-666X/14/1/6/pdf
BYU ScholarsArchive Citation
Warr, Chandler A.; Crawford, Nicole G.; Nordin, Gregory P.; and Pitt, William G., "Surface Modification of 3D Printed Microfluidic Devices for Controlled Wetting in Two-Phase Flow" (2022). Faculty Publications. 7677.
https://scholarsarchive.byu.edu/facpub/7677
Document Type
Peer-Reviewed Article
Publication Date
2022-12-20
Publisher
MDPI
Language
English
College
Ira A. Fulton College of Engineering
Department
Chemical Engineering
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