Team:Cambridge/Protocols/Spin Coating

Spin Coating

A method of producing a thin film on a substrate using a revolving stage and vacuum suction.

Theory

• The vacuum is used to hold the substrate in place via suction.
• The solution of interest is dropped onto the substrate and the thin film is formed due to the centrifugal force of the spinning rotor
• The rotation theoretically evenly spreads out the solution out and causes it to evaporate off leaving behind a thin film.
• Different rotation speeds and different rotation times results in different thickness of thin films, fine tuning is required for optimal results.

Practice

Solution Preparation

• Dissolve desired substance e.g. protein/polymer etc. in desired solvent e.g. HFIP, heptane, acetone and make up to desired concentration e.g. 10% weight-by-weight reflection-HFIP solution.
• tip: Vacuum centrifugation will produce pellets from solution which can be resuspended in the desired solvents

Loading and Running

1. Place desired substrate (in our case silicon or glass) onto the spin-coater and turn on vacuum suction
2. Initialise the run settings, typically spin speed (rpm) and spin time (seconds)
3. Pipette the desired volume onto the substrate, taking care to ensure the entire substrate is coated then close the lid. For volatile solvents like HFIP, it is recommended to pipette through the access hole in the lid and start immediately.
4. Open lid and remove substrate afterwards using tweezers. You may place on hotplate to evaporate remaining solvent

Safety

• Spin-coating was performed in the fume hood, with appropriate personal protection (in this case, safety goggles, labcoat and nitrile gloves)
• Keep the spin-coater closed at all times during spin-coating to avoid splashback.

Note: Always check solvent material safety data sheet for relevant safety equipment and first aid procedures