Polymerization Behavior and Kinetics during the Formation of Polymer-Stabilized Ferroelectric Liquid Crystals

1997 ◽  
Vol 30 (6) ◽  
pp. 1594-1600 ◽  
Author(s):  
C. Allan Guymon ◽  
Christopher N. Bowman
Keyword(s):  
Liquid Crystals ◽  
Ferroelectric Liquid Crystals ◽  
Polymerization Behavior ◽  
Polymer Stabilized

Formation of Polymer Stabilized Ferroelectric Liquid Crystals using a Fluorinated Diacrylate

1999 ◽  
Vol 559 ◽  
Author(s):  
C. Allan Guymon ◽  
Christopher N. Bowman ◽  
Christopher N. Bowman
Keyword(s):  
Liquid Crystal ◽  
Liquid Crystals ◽  
Polymer Network ◽  
Isotropic Phase ◽  
Ferroelectric Liquid Crystals ◽  
Smectic C ◽  
Electro Optic ◽  
Polymerization Behavior ◽  
Mechanically Stabilized ◽  
Polymer Stabilized

ABSTRACTFerroelectric liquid crystals (FLCs) have shown great potential for use in electro-optic and display technology due to their inherently fast switching speeds and bistability. Recently, considerable research has been devoted to FLCs mechanically stabilized by a polymer network. The network is formed typically by in situ polymerization of a monomer dissolved in the FLC. Because of the inherent order in the FLC, the polymerization behavior may be significantly different than what might be expected in solution polymerizations. These deviations result largely from the segregation properties of the monomer in the liquid crystal. One class of monomers, namely fluorinated acrylates, is a likely candidate for inducing novel segregation, polymerization and electro-optic behavior in polymer stabilized ferroelectric liquid crystals (PSFLCs). The use of fluorinated moieties has a significant impact on the phase and polymerization behavior of liquid crystal systems. This study focuses on the polymerization of a fluorinated diacrylate, octafluoro 1,6-hexanediol diacrylate (FHDDA), to form PSFLCs and the consequent impact of the polymerization on the ultimate performance. Interestingly, as the temperature is increased and the order of the system decreases, a dramatic increase in the polymerization rate is observed. This increase is especially prominent for polymerizations in the smectic C* phase for which the rate is more than five times that exhibited at much higher temperatures in the isotropic phase. As with other monomer/FLC systems, the segregation of the monomer plays a role in this polymerization behavior as the monomer segregates between the smectic layers of the liquid crystal. The segregation properties also significantly impact the ultimate electro-optic properties. Both ferroelectric polarization and response time of the PSFLC change markedly with different polymerization temperatures, and approach values very close to those of the neat FLC under appropriate polymerization conditions. This behavior not only provides a unique mechanism for rate acceleration in PSFLCs, but also paves the way for new methods to optimize performance in these materials.

Polymerization and Properties of Polymer-Stabilized Ferroelectric Liquid Crystals

MRS Bulletin ◽  
1997 ◽  
Vol 22 (9) ◽  
pp. 15-20 ◽  
Author(s):  
Christopher N. Bowman ◽  
C. Allan Guymon
Keyword(s):  
Liquid Crystals ◽  
Liquid Crystalline ◽  
Scanning Calorimetry ◽  
Ferroelectric Liquid Crystals ◽  
University Of Colorado ◽  
Crystalline Environment ◽  
Polarized Infrared Spectroscopy ◽  
The Many ◽  
The University ◽  
Polymer Stabilized

The following is based on the presentation made by Christopher N. Bowman, recipient of the MRS Outstanding Investigator Award, at the 1997 MRS Spring Meeting.I would like to focus on our recent work involving photopolymerizations of monomers in a liquid-crystalline environment. This work is one of the many aspects of photopolymerizations that we are focusing on at the University of Colorado. In particular this effort concentrates on understanding the influence of a liquid-crystalline medium and monomer segregation on polymerization behavior and polymer structure. These studies are of considerable importance for polymer-stabilized ferroelectric liquid crystals (FLCs) because of the enormous potential impact on the area.I will briefly introduce liquid crystals (LCs), FLCs, and photopolymerizations. I will then discuss the observed electrooptic properties and how these properties change as the LC phase during polymerization is varied. Finally I will address how polymerization kinetics are affected by the LC phase and monomer segregation. This discussion will include results from x-ray diffraction, polarized infrared spectroscopy, and differential scanning calorimetry experiments.

Field Sequential Full Color LCDs using Polymer-stabilized V-shaped Ferroelectric Liquid Crystals

2008 ◽  
Vol 364 (1) ◽  
pp. 78-85 ◽  
Author(s):  
Toru Fujisawa ◽  
Isa Nishiyama ◽  
Kazuaki Hatsusaka ◽  
Kiyofumi Takeuchi ◽  
Haruyoshi Takatsu ◽  
...  
Keyword(s):  
Liquid Crystals ◽  
Ferroelectric Liquid Crystals ◽  
Full Color ◽  
Polymer Stabilized

Polymer-Stabilized Ferroelectric Liquid Crystals Photocured at Nematic Phase

2009 ◽  
Vol 509 (1) ◽  
pp. 349/[1091]-355/[1097] ◽  
Author(s):  
Hideo Takahashi ◽  
Akihito Yokote ◽  
Hirokazu Furue
Keyword(s):  
Liquid Crystals ◽  
Nematic Phase ◽  
Ferroelectric Liquid Crystals ◽  
Polymer Stabilized
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