1. Liquid Crystals The Fourth State of Matter? Dr. Vance Williams
Department of Chemistry
Simon Fraser University

3. Liquid Crystals: Some Applications

5. Liquid Crystals: Not An Oxymoron
Most crystals are solids that are ordered in 3 dimensions.
Most liquids are completely disordered.
Some liquids are ordered in 1 or 2 dimensions (and therefore are “crystalline”).

6. Liquid Crystals
Smectic
Nematic
Columnar

7. Liquid Crystals: History
The first liquid crystal was discovered in 1888 when Friedrich Reinitzer noticed that a compound he was studying exhibited two melting points; one at 145 °C and a second at 178 °C.

8. Cholesteric Liquid Crystals
cholesterol
cholesteryl benzoate

9. Mood Rings and Thermometers
Thermochromism
Mood Rings and Thermometers

11. …this helix gets tighter as the temperature increases
molecules
form a helix... T
…this helix gets tighter as the temperature increases

12. LCDs and Polarized Light

13. Polarized Light

15. Polarized Light

16. Polarized Light

19. Inserting an organized, “birefringent” material between the polarizers allows some light to be transmitted.

20. Phases Under a Microscope
All imaged viewed through cross-polarized light.

33. Welding Masks
Solar cell

34. Welding Masks
Solar cell

35. “Smart” Windows

36. “Smart” Windows

37. Pressure Sensors

38. Pressure Sensors

40. Natural Liquid Crystals:
DNA

41. Department of Chemistry Simon Fraser University vancew@sfu.ca
Vance Williams
Department of Chemistry
Simon Fraser University