50 C overnight is way too long. 65 for an hour is usually the time.
Or RT if you leave it over night.

Hope this helps.

Petru

La data de , "Ali M. Koupaei"  a scris:
> Hello all!

> I made PDMS on a patterned silicon master; however after cross-linking at
> 50oC overnight, the PDMS film cannot be removed from the master uniform
> and nicely; in fact the master is gone and PDMS can only be removed
> partially so much so no patterned PDMS can be achieved.

> Does anyone have any idea how I can solve this problem and what is wrong
> with the master? As usual I am using a 10:1 ratio of elastomer to
> cross-linker. For another master I do not have the same problem and PDMS
> film can be thoroughly removed from the master and nothing remains on
> master.

> Thanks a lot!

> Ali