Off-Stoichiometry Improves Photostructuring of Thiol-Enes Through Diffusion-Induced Monomer Depletion
2016 (English)In: Microsystems and Nanoengineering, ISSN 2055-7434, Vol. 2, 15043Article in journal (Refereed) Published
Thiol-enes are a group of alternating copolymers with highly ordered networks used in a wide range of applications. Here, “click” chemistry photostructuring in off-stoichiometric thiol-enes is shown to induce microscale polymeric compositional gradients due to species diffusion between non-illuminated and illuminated regions, creating two narrow zones with distinct composition on either side of the photomask feature boundary: a densely cross-linked zone in the illuminated region and a zone with an unpolymerized highly off-stoichiometric monomer composition in the non-illuminated region. By the use of confocal Raman microscopy, it is here explained how species diffusion causes such intricate compositional gradients in the polymer, and how off-stoichiometry results in improved image transfer accuracy in thiol-ene photostructuring. Furthermore, increasing the functional group off-stoichiometry and decreasing photomask feature size is shown to amplify the induced gradients, which potentially leads to a new methodology for microstructuring.
Place, publisher, year, edition, pages
Nature Publishing Group, 2016. Vol. 2, 15043
thiol-ene, oste, OSTEmer, polymer, photopatterning, photolithography, monomer diffusion, click chemistry, Raman confocal microscopy, microfluidics
Nano Technology Textile, Rubber and Polymeric Materials
Research subject Electrical Engineering; Materials Science and Engineering
IdentifiersURN: urn:nbn:se:kth:diva-144992DOI: 10.1038/micronano.2015.43OAI: oai:DiVA.org:kth-144992DiVA: diva2:715469
Updated from accepted to published.