Koch Lab:Protocols/PDMS

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PDMS poured onto paterned wafer
PDMS in vacuum chamber
"ATM off", don't worry about the other two knobs, they should always be open
Open for 1 sec, just to put Oxygen in plasma cleaner chamber
Plasma cleaner
  1. Mix PDMS and curing agent in a container with a ratio of 10:1 (10 parts PDMS to 1 part curing agent)
    • This should be done in a small glass container, as it has been found experimentally that the two do not mix very well in larger containers and can cause damage to the silicon wafer.
    • It should be glass because it has also been found that containers made of polymers tend to introduce small fibers into the mixture and this can affect the optical properties of the PDMS
  2. Stir mixture sufficiently (3-4 mins, more is better)
  3. Poor in Petri dish
  4. Place on mask
  5. Place in oven for about 5 mins @ 75 degrees C
  6. Add about 60 grams of PDMS
  7. Place in vacuum until bubbles are all out
    • Place in vacuum for 30 seconds, remove for a minute, and repeat process
  8. Place in oven for about 1 hour at 65-70 degrees C
  9. Use cork borer to bore out columns for syringe tips
  10. Cut out desired patterns
  11. Wash PDMS and glass with ethanol and dry with Nitrogen glass
  12. Place glass and PDMS in plasma cleaner feature side up but not touching.
    • Preparing Plasma cleaner
      • circuit breaker on
      • atm closed
      • place plate over hole (make sure rubber seal is in plate)
      • wait for meter to get to 70mTorr or stop moving since it may never get to 70mTorr
      • add oxygen for 1 second (by opening smallest valve on the tank to the left of the plasma cleaner)
      • wait for gauge to get back to 70mTorr
      • line power on, switch to high
      • wait 13 seconds after PDMS begins to glow purple
        • It is possible to over plasma clean
      • turn everything off in reverse order
  13. Place back on glass slide and press down everywhere
  14. Place back in oven for 5 to 10 minutes