Hello everyone,
I am trying to make a PDMS channel using PR-1827 as a sacrificial layer.

The height of the photoresist is 5 um, and then i spin a 5 um coat of PDMS
on it. Etch away the PR and get a channel under the PDMS.

The problem I am facing is that the channel doesn't become hydrophilic
even after I put it in Oxygen Plasma. I have done 10 mins at 450 mT at
100W. The outside of the PDMS does become hydrophilic.

Am I working with too small of a channel depth or am I overlooking
something?? Do I need to treat it with Oxygen plasma for a few hours??

Please advise, as I have been stuck with this problem for
quite some time.

Thanks in advance
tushar