1. The Science and Technology of Liquid Crystals Peter J. Collings Department of Physics & Astronomy Swarthmore College June 21, 2007 Return to "Recent Talks" Page

2. Outline Introduction to Liquid Crystals Mechanical, Electrical, and Optical Properties Liquid Crystal Display Technology Chemistry of Liquid Crystals Biology of Liquid Crystals Return to "Recent Talks" Page

3. Phases of Matter Return to "Recent Talks" Page

4. Liquid Crystals L = 300 J/gmL = 30 J/gm solidliquid crystalliquid Return to "Recent Talks" Page

5. Orientational Order Order Parameter S = Return to "Recent Talks" Page

6. Order Parameter Return to "Recent Talks" Page

7. Smectic Liquid Crystals Return to "Recent Talks" Page

8. Typical Liquid Crystal Molecule Return to "Recent Talks" Page

9. Chiral Nematic Liquid Crystal Return to "Recent Talks" Page

10. Discotic Liquid Crystals Return to "Recent Talks" Page

11. Discotic Phases nematic columnar Return to "Recent Talks" Page

12. Lyotropic Liquid Crystals Return to "Recent Talks" Page

13. Lyotropic Phases Micelle (cross-section) Vesicle (cross-section) Return to "Recent Talks" Page

14. Liquid Crystal Phases of Aggregates Return to "Recent Talks" Page

15. Nematic Phase of Sunset Yellow Return to "Recent Talks" Page

16. Viscosity low viscosity high viscosity anisotropy! Return to "Recent Talks" Page

17. Polarization Return to "Recent Talks" Page

18. Birefringence Return to "Recent Talks" Page

19. Birefringence (continued) Return to "Recent Talks" Page

20. LCs between Crossed Polarizers E Return to "Recent Talks" Page

21. Nematic Liquid Crystal Return to "Recent Talks" Page

22. Smectic Liquid Crystal Return to "Recent Talks" Page

23. Chiral Nematic Liquid Crystal Return to "Recent Talks" Page

24. Selective Reflection condition for reflection: L 2 - L 1 = (P/2)(1+cos(  +  ))/cos  )= n if  =  and for n = 1, = Pcos  Return to "Recent Talks" Page

25. Temperature Sensors Return to "Recent Talks" Page

26. Liquid Crystal Display Return to "Recent Talks" Page

27. Twisted Nematic LCD Return to "Recent Talks" Page

28. Electrically Controlled Birefringence Return to "Recent Talks" Page

29. Computer Monitor Return to "Recent Talks" Page

30. Small Displays Return to "Recent Talks" Page

31. Light Shutters Return to "Recent Talks" Page

32. PDLC Windows & Displays Return to "Recent Talks" Page

33. Switchable Windows Return to "Recent Talks" Page

34. Liquid Crystal Droplets Return to "Recent Talks" Page

35. Biological Sensors Array of Antibodies in a Chromonic Liquid Crystal Crossed Polarizers Immune Complexes Return to "Recent Talks" Page

36. Synthesis of Liquid Crystals C - Core group (benzene, cyclohexane, pyrimidine rings) B - Bridging group (phenyl-, azo-, ester, Schiff’s base) L - Linking group (oxy-, carboxyl-) R - End group (hydrocarbon, -CN, -NO 2 ) X - Lateral group (-H, -F, -Cl, -Br, -NO 2 ) Return to "Recent Talks" Page

37. Double Twist Cylinders Return to "Recent Talks" Page

38. Simple Cubic Structure Return to "Recent Talks" Page

39. Blue Phase Single Crystals Return to "Recent Talks" Page

40. Phospholipid Bilayers Return to "Recent Talks" Page

41. Biology Cell Membranes Ordered substrate (hydrophilic, hydrophobic) Role of cholesterol (amount of order) Muscle Microfilaments (actin, myosin) Architecture (chiral nematic?) Microtubules (cytoskeleton, spindle fibers) DNA packing in chromosomes Return to "Recent Talks" Page

42. Medicine Sickle-Cell Anemia (abnormal hemoglobin aggregates?) Atherosclerosis (cholesterol esters in liquid crystal phase?) Anesthetics (environment of membrane proteins?) Cancer (order of microfilaments within cell?) Return to "Recent Talks" Page

43. Conclusions Liquid Crystals Are Interesting Scientifically Technologically Liquid Crystals Are Important Biology Chemistry Physics Engineering Liquid Crystals Are Beautiful! Return to "Recent Talks" Page