Dielectric and X-ray Studies of Eleventh and Twelfth Members of Two Isothiocyanato Mesogenic Compounds

• Authors: M. Jasiurkowska , A. Budziak , J. Czub , S. Urban
• Languages of publication: EN

Abstracts

EN

Results of the dielectric and X-ray studies of the long-alkyl-chain members (n=11, 12) of two homologous series: nBT (4-n-alkyl-4'-isothiocyanato-biphenyl) and nCHBT (4-trans-4'-n-alkyl-cyclohexyl-isothiocyanato-benzene) in their liquid crystalline phases are presented. These compounds exhibit different polymorphisms: the nematic phase for $n$CHBTs and the smectic E and smectic A phases for nBTs. The dielectric measurements were performed in a wide frequency range of 1 kHz-3 GHz. The layer thickness in the smectic E and smectic A phases and the orthorhombic unit cell parameters of the smectic E phase were determined using the small angle X-ray diffraction method. In the smectic E phase the layer-thickness-to-molecular-length ratios are found to be close to 1. The corresponding ratios observed for the smectic A phase of $n$BTs are considerably higher (≈1.24), which indicates that an alternating head-to-tail arrangement of molecules in the layers is favored. The rotational dynamics of molecules in the smectic E phases is discussed in relation to their packing in a unit cell.

Keywords

EN

61.10.Eq; 61.66.Hq; 64.70.Md; 77.22.-d; 77.22.Gm

Discipline

• 77.22.Gm: Dielectric loss and relaxation
• 77.22.-d: Dielectric properties of solids and liquids(for dielectric properties of tissues and organs, see 87.19.rf)
• 61.66.Hq: Organic compounds

• Publisher: Institute of Physics, Polish Academy of Sciences
• Journal: Acta Physica Polonica A
• Year: 2006
• Volume: 110
• Issue: 6
• Pages: 795-805

Dates

published

2006-12

received

2006-09-11

(unknown)

2006-11-27

Contributors

author

M. Jasiurkowska

• H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland

author

A. Budziak

• H. Niewodniczański Institute of Nuclear Physics, Polish Academy of Sciences, Radzikowskiego 152, 31-342 Kraków, Poland

author

J. Czub

• Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland

author

S. Urban

• Institute of Physics, Jagiellonian University, Reymonta 4, 30-059 Kraków, Poland

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Identifiers

DOI

10.12693/APhysPolA.110.795