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The Science and Technology of Liquid Crystals

The Science and Technology of Liquid Crystals. Peter J. Collings Department of Physics & Astronomy Swarthmore College June 21, 2007. Return to "Recent Talks" Page. Outline. Introduction to Liquid Crystals Mechanical, Electrical, and Optical Properties Liquid Crystal Display Technology

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The Science and Technology of Liquid Crystals

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  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 solid liquid crystal liquid L = 300 J/gm L = 30 J/gm Return to "Recent Talks" Page

  5. Orientational Order Order Parameter S = <(3cos2q - 1)/2> 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 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 l condition for reflection: L2 - L1 = (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 Crossed Polarizers Immune Complexes Array of Antibodies in a Chromonic Liquid Crystal 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, -NO2) X - Lateral group (-H, -F, -Cl, -Br, -NO2) 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

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