We have solution casted Sylgard 184 PDMS on commercial non woven fabric cast PES support. The membrane was dense, and stable under vacuum in a pervaporation set up. But while doing swelling test, the PDMS layer comes out of the PES after adding hydrocarbon liquid, like, hexane, benzene, octane etc within a minute. How to solve this? We want a stable dense membrane to separate two hydrocarbons by pervaporation.
PDMS materials typically swell a lot in hydrocarbon solvents. You can estimate the swelling of Sylgard 184 separately, on a little cube of material submerged in the solvent of your choice (measure weight change and optionally change of dimensions). The swelling creates strain between the PDMS and the substrate on which it is deposited, and that often results in delamination. I don't know the crosslinking density of Sylgard 184, but the delamination you see may imply that it is not cross-linked enough for your application, since cross-linking suppresses swelling. Of course mechanical, diffusion and other properties will change with more crosslinking.
Best bet in my opinion is to contact the supplier and ask for advice, since they certainly have many grades of PDMS (and other polysiloxane!) elastomers.
Thank you Dr. Cooper. We are in search of higher molecular weight PDMS and a different crosslinker.
- Badges
- Science topic
- Similar topics
- Linguistics
- Composition Studies
- Publication