Benvenuti in queste pagine dedicate a scienza ed arte. Amelia Carolina Sparavigna

Friday, February 25, 2011

Bent-Core Liquid Crystals

Most Cited Articles 2009 Japanese Journal Applied Physics
The 10 articles published in JJAP from 2006 to 2008 that were most frequently cited in 2009, in order of publication date. PDF files of the full text of these articles are available free of charge for one year from January 2011.

Bent-Core Liquid Crystals: Their Mysterious and Attractive World,  by Hideo Takezoe, and Yoichi Takanishi, Jpn. J. Appl. Phys. 45 (2006) 597 [Abstract] [Full Text PDF Free ]
Bent-Core Liquid Crystals: Their Mysterious and Attractive World
Structures and properties of liquid crystalline phases formed by bent-core molecules are reviewed. At least eight phases designated as B1–B8 have been found, being unambiguously distinguished from phases formed by usual calamitic molecules due to a number of remarkable peculiarities. In addition to B1–B8 phases, smectic A-like phases and biaxial nematic phases formed by bent-core molecules are also reviewed. The most attractive aspects of this new class of liquid crystals are in polarity and chirality, despite being formed from achiral molecules. The bent-core mesogens are the first ferroelectric and antiferroelectric liquid crystals realized without introducing chirality. Spontaneous chiral deracemization at microscopic and macroscopic levels occurs and is controllable. Moreover, achiral bent-core molecules enhance system chirality. The interplay between polarity and chirality provides chiral nonlinear optic effects. Further interesting phenomena related to polarity and chirality are also reviewed. [DOI: 10.1143/JJAP.45.597]
KEYWORDS: bent-core liquid crystals, polarity, chirality, ferroelectricity, antiferroelectricity, phase structure, layer structure, X-ray diffraction, nonlinear optics, SHG