Hi Jason,

you may try an additional plasma to get surfaces that are all hydrophilic.
To a certain extent you can "refresh" plasma treated surfaces, that spent a
long time at ambient. Microwave plasma works very nicely even in small
cavities, as the radicals will cause the surface treatment and not an ion
bombardment.

Another way might be to fill your device under vacuum (make sure that the
liquid is properly degased as well!).

Cheers

Thilo

-----Ursprüngliche Nachricht-----
Von: X J [mailto:[email protected]]
Gesendet: Mittwoch, 22. Dezember 2004 18:35
An: [email protected]
Betreff: [mems-talk] How to get rid of the bubbles in the microfluidic
device.


Dear colleagues,
  Hello!
  I work on the microfluidic devices. I found it really annoying that when
I inject the flow there will be always some air bubbles trapped in the
microfluidic devices (made of PDMS and glass). Is there any way to get rid
of them?
  Previously someone recommended to use the ultrasonic toothbrush to tap
the surface of PDMS. But maybe I did not use it correctly, there are still
some bubbles trapped.
  Can I deposit some additional layer to prevent air bubbles from being
trapped?
  For your information,
  The feature size of my device is about 50 um.
  The PDMS is a little bit hydrophobic, long time after treated by oxygen
plasma. And the glass is hydrophilic.

  Thanks a lot!


  Jason


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