Team:Cambridge/Experiments/Thin Films

We conducted a number of experiments with the thin films, outlined below.

Reflectin Thin Films I

• Description of the basic method
• Colourful thin films created with reflectin & HFIP
  • Thin film colour not uniform
• HFIP thin film control did not show structural colour

Reflectin Thin Films II

• Method refined in an attempt to reduce impurities
• Bovine Serum Album (BVA) control to test whether generic proteinacious thin films produce colour
  • Did not show structural colour
• Reflectin thin films appear to crystalize on drying

Reflectin Thin Films III

• Control indicates that Urea may be to blame for thin film crystalization
• More controls show that neither GFP nor BSA exhibit structural colour when spun into thin films

Colour Intense Films - First Breakthrough

• Less is more - using the same concentration, spinning a small volume leads to better wetting and more colour intense films
• Introducing the 'Piranha solution' for surface cleaning

Uniform Films and Multilayers

• Quality over quantity - purer reflectin and greater control over spin lead to colour uniformity
• Attempts to create multilayers with alternating PDMS and reflectin.
• Problems with stability of reflectin due to impurities hinder progress but produce 'protein art'

Attempts to increase film stability lead to first stable multilayer

• Dilution and centrifuging of samples and using only the very top layer seem to provide better stability for urea containing reflectin
• Dialysed protein seemed to be more stable however suffers from dewetting

Spectral Measurements of Thin Films

• Spectral measurements of single, double and triple refectin-PDMS layers and PDMS control with video footage
• Film swelling and colour changes induced by breathing due to reflectin layers illustrating the tunability of reflectin