Liquid Crystal Dispersions

The following sections are included:

• Dedication

• Preface

• Credits

• Contents

The following sections are included:

• The PDLC paradigm

• History

• Scope of the book

• References

The following sections are included:

• Polymer primer
  • Polymer structure and physical properties
  • Polymer chemistry
    • Addition polymerization
    • Step polymerization
    • Ring-opening polymerization

• Emulsion methods for PDLC films
  • Polyvinyl alcohol systems
  • Latex-based systems
  • Other water-based systems

• Phase separation methods for PDLC films
  • Polymerization-induce phase separation (PIPS)
    • Photoinitiated PIPS systems
      • Thiol-ene systems
        • Morphology of thiol-ene systems
      • Acrylate systems
        • Morphology of acrylate systems
      • Variations in photocured PDLC systems
        • Liquid crystal alignment
        • Modification of PDLC films after cure
        • Spatially-varying structures
      • Polymer network systems
        • Morphology of mesogenic network PDLC systems
    • Thermally initiated PIPS systems
    • Electron beam-initiated PIPS systems
  • Thermally-induced phase separation (TIPS)
  • Solvent-induced phase separation (SIPS)

• Other methods for PDLC formation
  • Imbibing porous structures with liquid crystal
  • Glass-dispersed systems
  • Dispersed silica systems
  • Mixtures of microspheres and liquid crystals

• Coatings, substrates, and film manufacture

• Aspects of film structure

• Film thickness

• Microscopy of PDLC films

• Liquid crystal domain size
  • Measurement of droplet size
    • Colloid sizing systems
    • Measurement of droplet size using electron microscopy
    • Light scattering
    • Estimation from reorientation fields
    • Analytic formulas for droplet size distributions
  • Droplet size distributions

• Liquid crystal solubility in the polymer matrix
  • Mass uptake
  • Polymer refractive index
  • Threshold for light scattering
  • Calorimetry
  • Electron microscopy

• Liquid Crystal/Polymer Phase Separation
  • Phase diagrams for liquid crystal/monomer mixtures
    • Description of phase diagrams
    • Measurement of phase diagrams
  • Phase separation in the binodal and spinodal regimes
    • Calculation of phase diagrams
  • Energetics and kinetics of PDLC film formation
    • Phase separation kinetics

• References

The following sections are included:

• Factors controlling nematic alignment
  • Theoretical considerations of droplet structures
    • Computational strategies
  • Defect structures
    • Escaped defect structures

• Analysis of director configurations
  • Optical microscopy
    • Calculation of droplet patterns
  • Nuclear magnetic resonance

• Catalog of droplet structures
  • Parallel wall alignment
    • Bipolar configuration
    • Concentric (aka toroidal or axial) structure
    • Twisted bipolar
  • Cholesteric droplets with parallel wall alignment
    • Radial line defect (spherulite structure)
    • Diametrical defect structure
    • Double-radial defect
    • Planar structures
    • Escaped defect structures in cholesteric systems
    • Focal conic textures
  • Perpendicular anchoring
    • Radial and twisted radial
    • Axial (equatorial)
    • Escaped radial
    • Cholesteric droplets with perpendicular alignment
  • Configurations with weak surface anchoring

• Transformations between droplet structures
  • Radial – Axial
  • Bipolar – Radial
  • Bipolar – Twisted bipolar and Bipolar – Concentric
  • Bipolar with twist wall
  • Cholesteric radial line (spherulite) – planar transition
  • Cholesteric spherulite helical unwinding
  • Radial – escaped radial transition
  • Negative – positive helical twist transitions
  • Temperature-driven transitions in radial droplets

• Assorted topics in confined systems
  • Surface transitions
  • Cylindrical structures
  • Microporous structures
  • Shape distortions in fluid-suspended droplets

• References

The following sections are included:

• Light scattering
  • Macroscopic properties
    • Measurement of light scattering
    • Film scattering profiles
    • Wavelength effects in light scattering
    • Multiple scattering effects
    • Light scattering at high fields
    • Light scattering and droplet director configuration
  • Models for light scattering of nematic droplets
    • Anomalous diffraction approximation
    • Radial droplets
    • Bipolar droplets with internal curvature
    • Experimental results
  • Rayleigh-Gans approximation
  • Other light scattering models
  • Light scattering at high droplet concentrations
  • Other aspects of PDLC light scattering
    • Reverse mode devices
    • Multiple scattering effects
    • 2-D vs. 3-D randomized alignment
    • Depolarization effects
    • Scattering in the infrared

• Dichroic effects in PDLC films
  • Emulsion-type dichroic PDLC films
  • Phase separation-type dichroic PDLC films

• PDLC film operating voltage
  • Definition of reorientation field
    • Fields and voltages
    • Hierarchical order parameters
  • Factors controlling reorientation fields
    • Droplet size and shape
      • A model based on shape anisotropy
    • Film conductivity and dielectric constant
    • Surface anchoring and alignment
      • Experimental investigation of anchoring in dispersed systems
      • Alignment by fields during cure
    • Polymer composition

• Switching speeds
  • Defining switching speeds
  • Experimental PDLC response times
  • Numerical models for PDLC response times
  • Means of improving response times

• Hysteresis and memory effects
  • Hysteresis effects
    • Sources of hysteresis
    • Reduction of hysteresis
  • Memory effects
    • Other systems exhibiting memory effects

• PDLC electrical properties
  • Equivalent circuit (impedance) analysis
    • 3-element model
  • Film capacitance
  • Distributed models
  • Conductivity and depolarization fields
  • Square wave excitation of PDLC films

• Some miscellaneous electro-optical effects
  • Reverse mode devices
  • Polarization-dependent scattering in sheared films
  • Nonlinear optical effects

• Chiral nematic dispersions
  • Cholesteric dispersions with negative dielectric anisotropy liquid crystal
    • Optics of cholesteric materials
  • Cholesteric dispersions with positive dielectric anisotropy liquid crystal
  • Flexoelectric effect in dispersed cholesteric systems

• Mesogenic polymer networks
  • Nematic fluids with mesogenic polymer networks
  • Morphology of mesogenic network composites
  • Electro-optics of mesogenic network/nematic composites
  • Mesogenic networks containing cholesteric liquid crystals
    • Monostable devices
    • Bistable devices
    • Multiple reflection wavelengths
  • Other network systems
    • Polymer stabilized display devices
    • Side chain liquid crystal polymer composites

• Chiral smectic dispersions
  • Chiral smectic materials
    • Some conventional chiral smectic device modes
      • Surface stabilized ferroelectric
      • Deformed helix mode
      • Antiferroelectric smectic C devices
      • Electroclinic effect
  • Chiral smectic dispersions
    • Linear SmC* devices
    • Bistable SmC* devices
    • Antiferroelectric SmC* devices
    • Electroclinic effects in dispersed SmA* systems

• References

The following sections are included:

• Comparison of TN and PDLC devices
  • Device construction
  • Mode of operation
  • Architectural windows
    • Scattering at zero field
      • Maximizing film scattering
      • Red bleedthrough in PDLC films
    • Haze at high fields
      • Standard PDLC films
      • Other low-haze PDLC films
    • Energy control
  • Projection displays
    • Screen luminance and display efficiency
    • Projector designs
      • Spatial light modulators
    • Scattering considerations in projection displays
    • PDLC material properties in projection displays
      • Operation voltage
      • Charge holding
      • Response time
      • Gray level response
    • Alternative PDLC systems in projection displays
      • Cholesteric based systems

• Direct-view scattering-mode displays
  • Reflective display illumination and contrast ratios
  • Display with rear reflectors
  • Transmissive display designs
  • Scattering displays incorporating polarizers

• Dichroic dye-based displays
  • Transmission properties of dichroic displays
  • Scattering properties in dichroic displays
  • Applications of dichroic displays

• Direct-view cholesteric displays
  • Reflective color cholesteric displays
  • Multiplexing drive schemes for cholesteric displays
    • Multiplexing with a large hysteresis loop
    • Multiplexing with bistable materials

• Miscellaneous applications

• References

The following sections are included:

• Index