Arichard:Protocols/Technics PEIIB
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Using the Technics PEIIB for PDMS surface activation[edit]
Motivation[edit]
Before performing reactions in PDMS wells, we want to coat the well surfaces in BSA; empirically, this greatly improves recovery. Due to the hydrophobicity of PDMS, however, water-based solutions are very difficult to spread (high contact angle). There are various techniques to activate the PDMS surface, including UV ozone, but in our hands the most effective method is oxygen plasma.
To do this, we use the Technics PEIIB Planar Etcher located in the Dry Etching module of the Nano3 facility.
Protocol[edit]
Note: Reservation requires equipment authorization.
- Sign in to the PEIIB log book. This will also be used to record pressure, power, time, and any malfunctions.
- Check that the device is powered on.
- The machine is stored under vacuum pressure. To open the lid, switch the VENT toggle to OPEN.
- Open the lid and place the device on the forward half of the metal grating, about halfway between center and the edge.
- Plasma generation seems to be inhibited when samples are directly centered.
- Close the lid and switch the VENT toggle to CLOSED.
- Switch the SOL'N toggle to OPEN. This will start the vacuum. Wait until the TORR indicator reaches 45. This may take several minutes.
- The machine loses its calibration periodically. Anything under 50 is still OK for our purposes.
- Switch the SOL'N toggle to CLOSED and switch the GAS 1 toggle to ON. Wait for the pressure to stabilize, then use the knob to adjust until the TORR indicator reads 200 +/- 5.
- Note: CW decreases pressure, CCW increases.
- Switch ON the POWER toggle. Use the knob to adjust until the WATTS indicator reads 200 +/- 10.
- Use the circular window on the front of the lid to check for plasma generation. We want a dark purple hue.
- Wait 3 minutes for treatment. Monitor both the pressure and power indicators.
- After 3 minutes, switch the POWER toggle to OFF, then switch the GAS 1 toggle to OFF.
- Switch the VENT toggle to OPEN. Wait for the lid to pop up slightly; this indicates the pressure is equalized.
- Open lid and remove sample. Close the lid and switch the SOL'N toggle to OPEN and wait for the TORR indicator to read 70.
- Switch the SOL'N toggle to CLOSED. Record the run in the logbook.
Notes[edit]
- This machine is frequently used without authorization. Most runs are short, and many users do not check reservations.
- If the plasma does not glow right away, you can try to light it by turning the power down to zero slowly and then rapidly turning it back up to 200.