New Materials and Effects

Mission
The project designs, creates and evaluates new liquid crystalline and polymeric materials and architectures with tailored properties and examines new effects in liquid crystals and polymers. Project members design and perform experiments and synthesize new compounds to investigate the properties of new materials, explore structure/property relationships, molecular orientations, and how the response of materials depends on molecular structure and phase behavior. Examples of new materials include high birefringence nematics, dichroic dyes, and new architectures. New molecular shapes may induce phases with new symmetries and/or significantly enhance the interaction between molecular characteristics and macroscopic properties of known phases.

Highlights

• Found twisted morphology in crystalline lamellae of isoregic chiral smectic C polymers
• Light scattering characterization of ferriclinic unit cells in smectics Cx
• Materials for and demonstration of light emission in discotic liquid crystals
• Characterization of inter- and intra- molecular interactions between dipoles and diacetylenes
• Synthesis of new soluble fluorinated polyimides with side-chains for alignment properties
• Prediction of stable lyotropic-thermotropic blue phases
• Synthesis of a macrocyclic mesogenic trimer
• Demonstration of mesogenic photoinitiator
  

Objectives

• Design, synthesis and characterization of higher twisting power nematics
• Develop networks, elastomers and physical composites
• Characterization of syn/anti/ferriclinic Smectic Cx
• Design and synthesis of new polyimides and polyionomers for alignment
• New banana shaped monomers and polymers
• Materials for and dynamics of twist disclinations in TGB phases
  

Deliverables

• Robust encapsulated liquid crystal droplets
• High pretilt polyimides
• Determination of solution properties of rigid rod polymers

Project Directors:  Rolfe G. Petschek and Frank W. Harris

Investigator	Topic
S.Z.D. Cheng (UA)	Materials Characterization
L.C. Chien (KSU)	Materials and Devices
F.W. Harris (UA)	Synthesis
A. Jakli (KSU)	Materials Characterization
S. Kumar (KSU)	X-Ray and Physical Studies
J.L. Koenig (CWRU)	Physical Properties
T. Kyu (UA)	Materials Characterization
M.E. Neubert (KSU)	Synthesis
R. Petschek (CWRU)	Theory
C. Rosenblatt (CWRU)	Physical Characterization
D. E. Schuele (CWRU)	Dielectric Measurements
K.D. Singer (CWRU)	NLO Measurements
S.N. Sprunt (KSU)	Physical Properties
P.L. Taylor (CWRU)	Theory
R. Twieg (KSU)	Materials Design and Synthesis

Mission
This project concentrates on the physics and chemistry of surface phenomena in liquid crystals (both thermotropic and lyotropic) and the development of new alignment materials and processes. Research topics include characterization of surface morphology and interactions; wetting phenomena; Langmuir-Blodgett and nano-films; and development of new alignment techniques and probes. Researchers study and model order parameters, phase transitions, defects, and elasticity.

Highlights

• Characterized anchoring strength as a function of surface roughness
• Developed new polyimides for precise control of surface tilt
• Modeled pretilt generation using double UV exposure
• Characterized interfacial potential and its spatial variation as a function of rubbing conditions
  

Objectives

• Characterize microstructure of interface
• Prepare and characterize new alignment materials such as low molecular weight molecules
• Develop new, non-buffing, non-optical techniques for alignment and polyimide patterning
• Investigate anchoring and surface-induced phenomena such as electro-optic response in layered thermotropic and non-traditional lyotropic and discotic LC materials
• Develop conductive and polar alignment layers
• Study wetting in various geometries
• Search for thermodynamic signature of surface wetting
  

Deliverables

• Low molecular weight alignment materials
• Alignment techniques for discotic materials
• Patternable, conducting alignment layers
• Correlation of surface optical properties with microstructure of the surface
• Theory of prewetting in cholesterics
  

Project Directors:  Charles Rosenblatt and Oleg Lavrentovich

Investigator	Topic
D.W. Allender (KSU)	Theory of Anchoring and Order
P.J. Bos (KSU)	Four-Domain TN Devices
L.C. Chien (KSU)	Materials and Devices
S.Z.D. Cheng (UA)	Characterization of Alignment Polymers
D. Finotello (KSU)	Confined Geometries
J.E. Fulghum (KSU)	Chemical Surface Characterization
F.W. Harris (UA)	Synthesis of Alignment Polymers
A. Jakli (KSU)	Surface Induced Phenomena
S. Kumar (KSU)	X-Ray Analysis of Surfaces; Electro-optics of Ferroelectrics
J.B. Lando (CWRU)	LB Films
O.D. Lavrentovich (KSU)	Surface Polarizations and Anchoring; Patterns
J.A. Mann (CWRU)	LB Films
R. Petschek (CWRU)	Theory of Surface Order
C. Rosenblatt (CWRU)	Surface Anchoring; Ordering in Confined Geometries
D.E. Schuele (CWRU)	LB Film Characterization
K.D. Singer (CWRU)	SHG of Surfaces
P.L. Taylor (CWRU)	Theory
J.L. West (KSU)	Characterization of Alignment Layers
D.K. Yang (KSU)	Polyimides for Alignment

Mission
The project focuses on improving the performance of liquid crystal devices and developing new device technologies. These improvements are sought through detailed modeling and characterization of devices as well as through development of new materials for passive optical components such as retardation layers, substrates, and polarizers. The goals for nematic liquid crystal displays are improvements in viewing angle, brightness, and chromaticity with good gray level performance. New concepts for lower power, bistable displays are being developed. Mathematical modeling of device optics plays a central role in the effort, providing guidance for new materials development and optical film design.

Accomplishments

• 2D display modeling program
• Wall-stabilized bistable twisted nematic
• Pi cell using high pretilt polyimide

Objectives

• Understand coupling of liquid crystal director with polymer networks and walls
• Study dynamics and defects in cholesteric liquid crystal devices
• Develop improved bistable, cholesteric texture (BCT) devices
• Synthesize new monomers for polymer stabilized liquid crystals
• Design drive schemes for bistable devices
• Develop two and three dimensional modeling for nematic devices, e.g., in-plane switching, multi-domain, and high resolution applications
• Explore new concepts in compensation films: develop positive and negative films with tilted optical axes
• Develop bistable nematic devices: investigate potential of bistable dichroic devices
• Develop projection and beam steering diffractive devices
  

Deliverables

• 3D director calculations of cholesteric transitions and doubly patterned electrode device
• Reliable 2D and 3D optical models
• Beam steering device
• Twisted negative birefringence compensation film
  

Project Directors: Jack Kelly and Deng-Ke Yang

Investigator	Topic
D.W. Allender (KSU)	Theory
P.J. Bos (KSU)	Display Development
S.Z.D. Cheng (UA)	Polymer Films
L.C. Chien (KSU)	Materials and Devices
E.C. Gartland, Jr. (KSU)	Numerical Modeling
F.W. Harris (UA)	Polymer Synthesis
J.R. Kelly (KSU)	Modeling and Device Physics
S. Kumar (KSU)	Physical Characterization
R. Petschek (CWRU)	Theory
R. Twieg (KSU)	Materials Design and Synthesis
D.K. Yang (KSU)	Display Development

Heterogeneous Structures

Mission
The project mission is to study phase separation and other processes which produce heterogeneous liquid crystalline materials (which may include dyes) and to understand the relationship between morphology and bulk physical properties and response. The aim is to have greater control of morphology in order to design and fabricate heterogeneous structures with desired optical and physical properties.

Accomplishments

• Constructed ruggedized TN display with field formed walls
• Live-mode PC based modeling of reaction driven phase separation
• Constructed web server for archiving, publishing, retrieving and disseminating scientific information
• Constructed polymer stabilized black-and-white reflective display
• Demonstrated sub-microsecond polymer stabilized cholesteric grating with >70% efficiency into first diffracted order
• Numerical simulation investigated anisotropic ordering and phase separation
• Measured coarsening and structure factor in aggregating particle networks
  

Objectives

• Experimentally and theoretically establish phase diagram of an LC/crosslinked network system
• Atomistic molecular modeling to follow the phase separation process
• Modeling of phase separation in non-uniform fields
• Optimize polymer stabilized cholesteric grating for diffraction efficiency
• Numerical modeling of kinetics of phase separation
• Preparation of PDLC by curing phase separated composites to reduce LC solubility in polymer matrix
• Produce the spectrum of particulate to fibrillar networks using a single monomer

Deliverables

• Patterned droplet size distribution via patterned fields
• Digital image library for information management component
  

Project Directors:  Peter Palffy-Muhoray, Steven D. Hudson, and Sharon C. Glotzer

Investigator	Topic
L.M. Bartolo (KSU)	Information Management
L.C. Chien (KSU)	Morphology and Phase Separation
S. Hudson (CWRU)	Materials Characterization
A. Jakli (KSU)	Materials Characterization
J.L. Koenig (CWRU)	IR Imaging
T. Kyu (UA)	Phase Separation
P. Palffy-Muhoray (KSU)	Modeling
D.E. Schuele (CWRU)	Electrical Characterization
S.N. Sprunt (KSU)	Physical properties
P.L. Taylor (CWRU)	Modeling
J.L. West (KSU)	Formulations and Coatings
D.K. Yang (KSU)	Formulations and Display Development

  S.C. Glotzer (NIST), S.A. Langer (NIST), A.J. Liu (UCLA)
  G. Smith (GM), G. Held (IBM), H. Yuan (dpiX, A Xerox Company)

Optical Switching and Storage

Mission
This project explores novel device concepts, materials and phenomena related to optical information storage and switching. Potential applications include electro-optic switches, shutters, modulators, optical power limiters, diffractive elements, photorefractive devices, frequency conversion, and mechanically responsive devices. Novel symmetries and structures will be explored. Materials under study include low molecular weight mesogens, dye-doped liquid crystals and polymers, liquid crystal polymers and elastomers, chiral materials and polymers. A variety of measurement techniques are being utilized to gain understanding of nonlinear optical phenomena and physical origins of effects useful in optical storage and switching. Nonlinear optical techniques are employed to investigate surface alignment structures, mechanisms and dynamics.

Highlights

• Synthesis of model chiral molecules and polymers for investigation of multidimensional optical nonlinearities
• Developed understanding of pyroelectric, dielectric, and nonlinear optical properties of functionalized siloxane copolymer Langmuir-Blodgett films
• Observation and elucidation of optically driven ratchet mechanism for photoalignment
• Developed analytic solution of Maxwell's equation in general homogeneous systems
  

Objectives

• Investigate chiral and other multidimensional materials for nonlinear optics and optomechanical control
• Explore new materials and orientation schemes for second order processes
• Investigate new liquid crystal materials for photorefraction
• Investigate materials and concepts for volume holography
• Investigate liquid crystalline elastomers for opto- and electro-mechanical control
• Develop techniques for characterizing the structure, dynamics, and mechanisms of molecular alignment at interfaces
• Investigate optically induced phase separation
• Study structure, phases and nonlinear optical properties of novel Langmuir-Blodgett films

Demonstrations

• Demonstrate quadrupolar second-order nonlinear optical effects
• Demonstrate hologram in polymer stabilized liquid crystal

Project Directors: Peter Palffy-Muhoray and Kenneth Singer