Hi,

It sounds fairly strange to me that PDMS should shrink less if cured at room
temperature compared to curing in an oven if precaution is taken to remove
entrapped air (as described before). If I don't mix up something, shrinkage
occurs only due to evaporation of solvent and increased of cross-linking.. So
why should PDMS shrink less if cured at room temperature (if the final
"hardness" of the cured PDMS) is the same ?! Of course it is very likely that
the internal stress is higher for fast cured PDMS (oven) than compared to slow
curing (room temperature).

Otherwise, I've never had problems with curing at room temperature (as well as
oven). Commonly I let it cure over night at room temperature and then, if higher
stiffness was required further curing at 60C. But def. You should try to use a
Teflon-coating if you have trouble with demolding.

Good luck
maria


-----Original Message-----
From: mems-talk-bounces+maria.matschuk=nanotech.dtu.dk@memsnet.org [mailto:mems-
talk-bounces+maria.matschuk=nanotech.dtu.dk@memsnet.org] On Behalf Of amit
asthana
Sent: 5. april 2011 00:40
To: mems-talk@memsnet.org
Subject: [mems-talk] Is it possible to make PDMS mold in room temperature?

Hello Righeira,

Yes, it is possible to cure PDMS at room temperature. I usually keep the
PDMS at room temperature (20 to 25 degree C) for 12 to 24 hours. This method
is specially good if less shrinkage of cured PDMS is required.

best

Amit