May 19 - May 25

Week 8
During this week's lab, the final prototype was created using the 70% liquid crystal to polymer ratio determined in Week 7. This model was constructed on conductive glass plates as opposed to the plastic substrates because glass creates a better seal with fewer air bubbles within the thin film. In addition to forming a more effective seal, the glass also allowed the wires to be soldered directly onto the plates. The final prototype can be connected directly to the voltage supply through these wires, which serve to set up a potential difference across the thin film. Below is the ratio of polymer to liquid crystal within the PDLC thin film of the final prototype. 

Polymer	Mass Added	Experimental Ratio
0.15 g	0.3571 g	0.702
Liquid Crystal	Mass Added	Experimental Ratio
0.35 g	0.1517 g	0.298

After measuring the correct ratio, spacers were added to the mixture in order to distribute the thin film at a uniform thickness of 8 microns. The balloon press was again used to flatten the film between the plates uniformly. A latex balloon inflates over the glass and thin film, applying a great deal of pressure that distributes the film evenly between the plates. The seal is created by the immense pressure and then the plates are cured for approximately five minutes. This serves to harden the film so that the liquid crystal can set and a voltage can be applied across the plates. 
Once the prototype had been cured, the wires were soldered onto opposite sides of the conductive plates using an equally conductive metal pellet.