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Showing papers by "Jan Jadżyn published in 2004"


Journal ArticleDOI
TL;DR: Mesogenic compounds belonging to the two well-known -cyanophenyl, and -isothiocyanatophenyl homologous series, show an essential difference in the pretransitional dielectric behavior in the vicinity of the isotropic to nematic (I-N) phase transition.
Abstract: Mesogenic compounds belonging to the two well-known -cyanophenyl, and -isothiocyanatophenyl homologous series, which distinctly differ in the molecular polarity (-C identical with N, 5D; -N=C=S, 2.5D), show an essential difference in the pretransitional dielectric behavior in the vicinity of the isotropic to nematic (I-N) phase transition. Taking into account the results presented in Phys. Rev. E 67, 041705 (2003), the features of the I-N transition observed for the less polar mesogens are characteristic for the first order phase transition, whereas in the case of the strongly polar ones, the I-N transition is undoubtedly close to the second order.

28 citations


Journal ArticleDOI
TL;DR: In this article, the temperature behavior of the splay and bend elastic constants measured for n-hexyloxycyanobiphenyl and noctyloxycyclanobinhibenyl mixtures was analyzed.
Abstract: The paper presents temperature behavior of the splay and bend elastic constants measured for n-hexyloxycyanobiphenyl and noctyloxycyanobiphenyl mixtures — a system exhibiting the re-entrant nematic phase. It was shown that singularities in the elastic properties of the system concern not only the nematic phase (the well-known pre-smectic effects) but first of all — the smectic A phase, in which the splay and bend deformations, normally not allowed for the layered structures, can be induced.

15 citations


Journal ArticleDOI
TL;DR: In this paper, the electric Fredericksz transition in 8CB-based ferronematics exposed to strong magnetic field was studied both theoretically (by means of the Burylov and Raikher's theory) and experimentally (using capacity measurements).

14 citations


Journal ArticleDOI
TL;DR: In this article, the results of viscosity measurements performed on 1,2-hexanediol in water and n-, s- and t-butanol solutions in the whole range of concentrations, at different temperatures, were determined.
Abstract: The paper presents the results of viscosity measurements performed on 1,2-hexanediol in water and n-, s- and t-butanol solutions in the whole range of concentrations, at different temperatures. The activation energy for viscous flow of the solutions and the viscosity excess, were determined.

11 citations


Journal ArticleDOI
TL;DR: The results of viscosity measurements performed on 1,2- and 1,4-butanediol in n-, s- and t-butanol solutions in the whole range of concentration, at different temperatures, were determined in this paper.
Abstract: The paper presents the results of viscosity measurements performed on 1,2- and 1,4-butanediol in n-, s- and t-butanol solutions in the whole range of concentration, at different temperatures. The activation energy for viscous flow of the solutions and the viscosity excess were determined. The excess shows a peculiar behavior for 1,4-butanediol in t-butanol solutions.

5 citations




Proceedings ArticleDOI
01 Sep 2004
TL;DR: In this paper, the structural transitions in thermotropic ferronematic, i.e., nematic liquid crystal (8CB) doped with fine magnetic particles (d ~ 10 nm), exposed to combined electric and magnetic fields, were studied within the Burylov and Raikher's theory.
Abstract: The structural transitions in thermotropic ferronematic, i.e. nematic liquid crystal (8CB) doped with fine magnetic particles (d ~10 nm), exposed to combined electric and magnetic fields, were studied within the Burylov and Raikher's theory. Using the found formulas for the threshold fields of studied transitions and their values obtained by the capacitance measurements, the anchoring energy W of liquid crystal molecules on the magnetic particles surfaces, as well as parameter ω, determining the type of anchoring, were calculated. The calculated values indicated the presence of soft, or some intermediate state between soft and rigid anchoring, in studied ferronematic. These results are in agreement with the Burylov and Raikher's theory of thermotropic ferronematics.© (2004) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.

Journal Article
TL;DR: The structural instabilities in ferronematics based on different types of liquid crystals, exposed to electric or magnetic fields oriented perpendicular (Fredericksz transition) and parallel to the initial director, were studied within the Burylov and Raikher's theory as discussed by the authors.
Abstract: The structural instabilities in ferronematics based on different types of liquid crystals, exposed to electric or magnetic fields oriented perpendicular (Fredericksz transition) and parallel to the initial director, were studied within the Burylov and Raikher's theory. Using the capacitance measurements the critical electric (magnetic) fields E F N (B F N ), corresponding to the Fredericksz transition, and fields E m a x , (B m a x ,), at which the initial perpendicularity between director n and magnetic moment m breaks-down in field parallel to the initial director, were found. These values were then used for the estimation of the surface density of the anchoring energy W of liquid crystal molecules on the magnetic particle surface.