Showing papers by "Grzegorz Czechowski published in 1993"
TL;DR: In this paper, the isotropic phase of a series of mesogenic molecules of 1-[3-n-alkyl-biphenyl]-2-[4-isothiocyanatophenyl]ethane was studied.
Abstract: Dielectric relaxation studies have been performed for the isotropic phase of a series of mesogenic molecules of 1-[3-n-alkyl-biphenyl]-2-[4-isothiocyanatophenyl]ethane, CnH 2η+1 −φ−φ−CH 2 CH 2 −φ−NCS (n-TPEB), for n = 7, 8 and 9. Two Debye-type dielectric absorption bands have been interpreted as corresponding to the rotation around the short and long molecular axis
4 citations
15 Oct 1993
TL;DR: In this paper, the homologous series of 4-isothiocyanatophenyl 4-(trans-4-alkylcyclohexyl) benzoates containing members with alkyl chain ethyl to dodecyl were synthesized and their phase transition temperatures, smectic layer spacing, and dielectric permittivity were measured.
Abstract: The homologous series of 4-isothiocyanatophenyl 4-(trans-4-alkylcyclohexyl) benzoates containing members with alkyl chain ethyl to dodecyl were synthesized and their phase transition temperatures, smectic layer spacing, and dielectric permittivity were measured. It was observed that smectic A1 layer spacing is expanding from d/1 on the order of magnitude 1 to d/1 on the order of magnitude 1.1 when alkyl is increasing from butyl to dodecyl. This behavior is accompanied by the great change in (epsilon) (perpendicular) which is strongly increasing from pentyl to octyl and then from nonyl begins to decrease. It was proposed to term smectic A1 with d/1 > 1 enhanced smectic A1 (A1c).© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
1 citations
15 Oct 1993
TL;DR: In this article, the elastic constants for splay, bend and twist modes of 8-OCB were determined on the basis of threshold values Bc and Uc, and the values of critical exponents obtained from the temperature dependence of K11 and K33 in the vicinity of N-SA phase transition were discussed.
Abstract: The Frederiks transitions for the n-octyloxycyanobiphenyl (8-OCB) placed in the external magnetic and electric field as a function of the temperature have been studied. On the basis of threshold values Bc and Uc, the elastic constants for splay, bend and twist modes are determined. The magnetic anisotropy of 8-OCB as a function of temperature has been determined. The K11 and K33 elastic constants show the pretransitional nematic- smectic A effect. The values of critical exponents obtained from the temperature dependence of K11 and K33 in the vicinity of N-SA phase transition are discussed.© (1993) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.
1 citations