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