The impact of ionic contribution to dielectric permittivity in 11CB liquid crystal and its colloids with BaTiO nanoparticles.

The report shows the temperature behavior of the real part of dielectric permittivity in the static (dielectric constant) and low-frequency (LF) domains in bulk samples of 11CB and its BaTiO-based nanocolloids. The study covers the isotropic liquid (I), nematic (N), smectic A (SmA), and solid crystal (Cr) phases. For each phase, the dominance of pretransitional fluctuations, significantly moderated by nanoparticles, is shown.

The fluctuation-driven dielectric properties of liquid crystalline 8OCB and its nanocolloids.

Results of broadband dielectric spectroscopy studies in liquid crystalline octyloxycyanobiphenyl (8OCB) and its colloids with BaTiO nanoparticles (paraelectric, diameter = 50 nm) are presented. Studies were carried out in isotropic liquid, nematic, smectic A and solid crystalline phases. They are supported by derivative-based and distortion-sensitive analyses, revealing a set of universal scaling patterns for temperature evolution of static and dynamic dielectric properties.

Impact of ferroelectric and superparaelectric nanoparticles on phase transitions and dynamics in nematic liquid crystals.

Results of broadband dielectric spectroscopy (BDS) studies of pure liquid crystalline (4-pentyloxy-4-biphenylcarbonitryle) 5OCB and its nanocolloids with BaTiO_{3} nanoparticles (NPs) under varying pressure and temperature are presented. The notable impact of NPs on phase transitions and dynamics was found. Particularly strong impact on pretransitional behavior was observed for relatively low concentrations of NPs, which can be related to the NPs-induced disorder.

Development of the HS-SPME-GC-MS/MS method for analysis of chemical warfare agent and their degradation products in environmental samples.

After World War II approximately 50,000 tons of chemical weapons were dumped in the Baltic Sea by the Soviet Union under the provisions of the Potsdam Conference on Disarmament. These dumped chemical warfare agents still possess a major threat to the marine environment and to human life. Therefore, continue monitoring of these munitions is essential.

Preparation and application of sol-gel acrylate and methacrylate solid-phase microextraction fibres for gas chromatographic analysis of organoarsenic compounds.

Novel solid-phase microextraction (SPME) fibres containing methyl, ethyl, butyl acrylate and methacrylate were first prepared by a sol-gel technique and investigated for determination of selected organoarsenic compounds (lewisite, methyldichloroarsine, phenyldichloroarsine, diphenylchloroarsine and triphenylarsine) from water samples. The influence of sorption and desorption temperature and time for extraction efficiency were examined. The best new fibre coatings (methyl acrylate (MA), methyl methacrylate (MMA) and combination of methyl acrylate and methacrylate (MA/MMA)) for analysis of organoarsenic compounds were selected and compared with commercial fibres.

Glassy dynamics in the isotropic phase of a smectogenic liquid crystalline compound.

The temperature evolution of the primary relaxation time in the isotropic phase of 4-cyano-4'-tetradecylbiphenyl (14CB) above the isotropic-smectic A (I-SmA) transition is discussed. Based on the enthalpy space and distortion-sensitive analysis, the prevalence of the mode coupling theory (MCT) "critical" and "glassy" dynamics is shown. The obtained singular dependence is related to the MCT critical temperature located approximately 48 K below the clearing (I-SmA) temperature.

Pretransitional behavior in the isotropic phase of a nematic liquid crystal with the transverse permanent dipole moment.

The results presented give the evidence for the quasicritical, pretransitional behavior of dielectric properties in the isotropic phase of a rodlike nematic liquid crystal with the transverse permanent dipole moment. Studies were conducted in 2-cyano-4-pentylbiphenyl 4-(trans-4-pentylcyclohexyl) benzoate, focusing on the static-and ionic-dominated low-frequency (LF) regions. For the static dielectric permittivity [epsilon(')(T)] the application of the derivative analysis revealed the pretransitional anomaly associated with the specific heat exponent alpha approximately 0.

Mode coupling behavior in glass-forming liquid crystalline isopentylcyanobiphenyl.

Linear and nonlinear dielectric measurements of liquid crystalline chiral isopentylcyanobiphenyl (5*CB) and n -pentylcyanobiphenyl (5CB), combined with viscosity eta (T) data, are presented. The 5*CB compound glassifies on cooling in the cholesteric phase whereas 5CB crystallizes in the nematic phase. In both compounds the temperature evolution of dielectric relaxation times, the dc conductivity, and the viscosity are well described by the "critical-like" description from mode coupling theory (MCT).