Cleaning procedure depends on what kind of dirt is sticking to the surface and how fragile the surface is.
- Microscope slides, cover glass, objectives and lenses: cleaning with paper/Q-tips is OK
- Chrome on glass photomasks:
- High-purity Isopropyl Alcohol (IPA)
- Cleanroom-grade, lint-free wipe.
- Acetone may also be used in specific cases involving heavy organic contamination or adhesive residues.
- To avoid damaging the chrome the use of paper/Q-tips should be very light or avoided
- "Sticky dirt", SU8, etc, in rising order:
- Water + detergent + rubbing with paper/Q-tips
- Ultrasound bath with acetone at room temp or higher temp
- Acetone bath + rubbing with paper/Q-tips
- Piranha solution (we don't let students use this)
- Light soiling (e.g., fingerprints or dust):
- A gentle wipe with IPA is typically all that’s required.
Final cleaning (to remove last residues of organics) and activation of glass surface:
- Plasma cleaner in room 128
- Deep UV in Giæver lab:
- Place the glass side to be activated facing up towards the UV source
- Turn on notrigen flow for 1 minute
- Turn on UV lamps and illuminate for 5 minutes
- Immediately use the activated, hydrophilic glass for downstream processes like micro-patterning, PLL-g-PEG coating, or adhesive bonding.
Other labs procedures:
Activation of glass surface
- Photolytic Breakdown: High-energy UV photons break molecular bonds (like C-H, C-C, and C-O) in organic impurities on the glass.
- Ozone Generation: Shorter wavelengths (such as 185 nm) generate ozone (O₃) from ambient oxygen, which further oxidizes broken organic fragments into volatile gases like CO₂ and H₂O.
- Hydrophilicity: The process introduces polar functional groups—such as hydroxyl (–OH)—onto the silicate surface, rendering it highly hydrophilic and increasing surface energy.
- Immediately use the activated, hydrophilic glass for downstream processes like micro-patterning, molecular functionalization (e.g., PLL-g-PEG coating), or adhesive bonding.