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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 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 • Chemistry of Liquid Crystals • Biology of Liquid Crystals Return to "Recent Talks" Page
Phases of Matter Return to "Recent Talks" Page
Liquid Crystals solid liquid crystal liquid L = 300 J/gm L = 30 J/gm Return to "Recent Talks" Page
Orientational Order Order Parameter S = <(3cos2q - 1)/2> Return to "Recent Talks" Page
Order Parameter Return to "Recent Talks" Page
Smectic Liquid Crystals Return to "Recent Talks" Page
Typical Liquid Crystal Molecule Return to "Recent Talks" Page
Chiral Nematic Liquid Crystal Return to "Recent Talks" Page
Discotic Liquid Crystals Return to "Recent Talks" Page
Discotic Phases nematic columnar Return to "Recent Talks" Page
Lyotropic Liquid Crystals Return to "Recent Talks" Page
Lyotropic Phases Micelle (cross-section) Vesicle (cross-section) Return to "Recent Talks" Page
Liquid Crystal Phases of Aggregates Return to "Recent Talks" Page
Nematic Phase of Sunset Yellow Return to "Recent Talks" Page
Viscosity low viscosity low viscosity high viscosity anisotropy! Return to "Recent Talks" Page
Polarization Return to "Recent Talks" Page
Birefringence Return to "Recent Talks" Page
Birefringence (continued) Return to "Recent Talks" Page
LCs between Crossed Polarizers E Return to "Recent Talks" Page
Nematic Liquid Crystal Return to "Recent Talks" Page
Smectic Liquid Crystal Return to "Recent Talks" Page
Chiral Nematic Liquid Crystal Return to "Recent Talks" Page
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
Temperature Sensors Return to "Recent Talks" Page
Liquid Crystal Display Return to "Recent Talks" Page
Twisted Nematic LCD Return to "Recent Talks" Page
Electrically Controlled Birefringence Return to "Recent Talks" Page
Computer Monitor Return to "Recent Talks" Page
Small Displays Return to "Recent Talks" Page
Light Shutters Return to "Recent Talks" Page
PDLC Windows & Displays Return to "Recent Talks" Page
Switchable Windows Return to "Recent Talks" Page
Liquid Crystal Droplets Return to "Recent Talks" Page
Biological Sensors Crossed Polarizers Immune Complexes Array of Antibodies in a Chromonic Liquid Crystal Return to "Recent Talks" Page
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
Double Twist Cylinders Return to "Recent Talks" Page
Simple Cubic Structure Return to "Recent Talks" Page
Blue Phase Single Crystals Return to "Recent Talks" Page
Phospholipid Bilayers Return to "Recent Talks" Page
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
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
Conclusions • Liquid Crystals Are Interesting • Scientifically • Technologically • Liquid Crystals Are Important • Biology • Chemistry • Physics • Engineering • Liquid Crystals Are Beautiful! Return to "Recent Talks" Page