Thin PDMS films using long spin times or tert-butyl alcohol as a solvent.

• Main Authors: John H Koschwanez, Robert H Carlson, Deirdre R Meldrum
• Format: Article
• Language: English
• Published: Public Library of Science (PLoS) 2009-01-01
• Series: PLoS ONE
• Online Access: http://europepmc.org/articles/PMC2642993?pdf=render

Thin polydimethylsiloxane (PDMS) films are frequently used in "lab on a chip" devices as flexible membranes. The common solvent used to dilute the PDMS for thin films is hexane, but hexane can swell the underlying PDMS substrate. A better solvent would be one that dissolves uncured PDMS but doesn't swell the underlying substrate. Here, we present protocols and spin curves for two alternatives to hexane dilution: longer spin times and dilution in tert-butyl alcohol. The thickness of the PDMS membranes under different spin speeds, spin times, and PDMS concentrations was measured using an optical profilometer. The use of tert-butyl alcohol to spin thin PDMS films does not swell the underlying PDMS substrate, and we have used these films to construct multilayer PDMS devices.