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Ferroelectric Liquid Crystal (ferroelectric + liquid_crystal)

Distribution by Scientific Domains
Polymers and Materials Science50%

Selected Abstracts

Electrically Tuneable Liquid Crystal Photonic Bandgaps

ADVANCED MATERIALS, Issue 38-39 2009
Su Seok Choi
Electrically controlled color tuning of the photonic bandgap and electrically induced multiple photonic bandgaps from a chiral nematic liquid crystal mixture doped with a ferroelectric liquid crystal. [source]

Pyroelectric investigations of a hydrogen bonded ferroelectric liquid crystal gel by LIMM

POLYMERS FOR ADVANCED TECHNOLOGIES, Issue 1 2005
Jianjun Li
Abstract The laser intensity modulation method (LIMM) is employed to determine spatially resolved polarization distributions in sandwich cells containing a hydrogen-bonded ferroelectric liquid crystal (FLC) gel. At no external electric fields, contributions to the distributions at the surface of the FLC layer are dominating in all the samples with different concentration of gel former. These are attributed to non-vanishing polarization due to surface interaction. In this case, the effect of hydrogen-bonded network on the polarization distribution is not visible. In external electric fields, additional contribution to the resulting distribution caused by the induced polarization due to unwinding the FLC helix has been observed. Furthermore, the influence of hydrogen-bonded network on the polarization distribution is also detected when the gel former content is increased up to 5.0,wt%. Therein the shape of the measured pyrospectra is completely different to other FLC gel samples with lower gel former concentration, where their maximum distributions still locate at the surface of FLC layer which is comparable to the initial field-free state. These result indicate that the helical structure and orientation director of FLC are able to be stabilized effectively by the gel network even under strong external electric field. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Photorefractive effect of ferroelectric liquid crystals

THE CHEMICAL RECORD, Issue 1 2006
Takeo Sasaki
Abstract This paper reviews our recent work on the photorefractive effect of ferroelectric liquid crystals (FLCs). The photorefractive effect is defined as the optical modulation of the refractive index of a medium as a result of a variety of processes. The interference of two laser beams in a photorefractive material establishes a refractive index grating. This phenomenon enables the creation of different types of photonic applications. FLCs exhibit fast electric field response, and the orientation of the molecular axis of FLCs changes its direction according to the change in direction of the spontaneous polarization (Ps). When two laser beams interfere in a photoconductive FLC, an orientational grating is formed. The mechanism of the formation of the grating is based on the response of the Ps to the photoinduced internal electric field. The time of formation of the refractive index grating is significantly shorter in FLC materials. © 2006 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 6: 43,51; 2006: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.20071 [source]