Showing papers by "Jan Jadżyn published in 2013"
TL;DR: The response in capacitance to low external magnetic fields of suspensions of spherical magnetic nanoparticles, single-wall carbon nanotubes, and SWCNT functionalized with Fe(3)O(4) nanoparticles in a nematic liquid crystal has been studied experimentally.
Abstract: The response in capacitance to low external magnetic fields (up to 0.1 T) of suspensions of spherical magnetic nanoparticles, single-wall carbon nanotubes (SWCNT), SWCNT functionalized with carboxyl group (SWCNT-COOH), and SWCNT functionalized with Fe${}_{3}$O${}_{4}$ nanoparticles in a nematic liquid crystal has been studied experimentally. The volume concentration of nanoparticles was ${\ensuremath{\phi}}_{1}={10}^{\ensuremath{-}4}$ and ${\ensuremath{\phi}}_{2}={10}^{\ensuremath{-}3}$. Independent of the type and the volume concentration of the nanoparticles, a linear response to low magnetic fields (far below the magnetic Fr\'eederiksz transition threshold) has been observed, which is not present in the undoped nematic.
50 citations
TL;DR: In this article, the dielectric spectra corresponding to the static regime of dimethyl sulfoxide + water mixtures were recorded in the whole concentration range and in the temperature range from (253.15 to 333.15) K.
Abstract: The dielectric spectra corresponding to the static regime of dimethyl sulfoxide + water mixtures were recorded in the whole concentration range and in the temperature range from (253.15 to 333.15) K. For the mixtures rich in DMSO (0.60 < xDMSO ≤ 1, x = mole fraction) and rich in water (0 ≤ xDMSO < 0.1), it was possible to perform the investigations both in the liquid and solid phases of the samples. The determined melting temperatures were compared to the data available in the literature. The deviation from the additivity of the measured static permittivity of DMSO + water mixtures shows a maximum for xDMSO ≈ 0.35, indicating formation at that concentration of intermolecular entities (most probably they are 1DMSO·2H2O hydrogen-bonded complexes) of a relatively enhanced polarity.
43 citations
TL;DR: In this article, the impedance spectrum of ionically conducting dipolar liquid is composed of two bands which correspond to the two dynamic electric phenomena occurring in the liquid: the ionic...
Abstract: The paper shows that the impedance spectrum of ionically conducting dipolar liquid is composed of two bands which correspond to the two dynamic electric phenomena occurring in the liquid: the ionic...
10 citations
TL;DR: In this paper, the magnetic Freedericksz transition was studied in ferronematics based on the nematic liquid crystal 4-(trans-4'-n-hexylcyclohexyl)-isothiocyanatobenzene (6CHBT).
Abstract: Magnetic Freedericksz transition was studied in ferronematics based on the nematic liquid crystal 4-(trans-4'-n-hexylcyclohexyl)-isothiocyanatobenzene (6CHBT). 6CHBT was doped with rod-like magnetic particles of different size and volume concentration. The volume concentrations of magnetic particles in the prepared ferronematics were $\phi_1$ = 10$^{-4}$ and $\phi_2$ = 10$^{-3}$. The structural changes were observed by capacitance measurements that demonstrate a significant influence of the concentration, the shape anisotropy, and/or the size of the magnetic particles on the magnetic response of these ferronematics.
10 citations
TL;DR: In this article, the structural modifications of mesogenic molecules lead to unfavorable changes in some important physical properties of liquid crystalline material, such as a shift in the clearing temperature, for example, or can lead even to a disappearance of the mesophase.
Abstract: In the paper, we show how some modifications in the chemical structure of mesogenic molecules can lead to an essential increase of the dielectric permittivity of liquid crystalline material due to the reduced molecular ability to the antiparallel dipolar aggregation. As an example, the static permittivities of two nematogenic homologous series, CnH2n+1PhPhCN and CnH2n+1PhCOOPhCN, are analyzed. However, the structural modifications of mesogenic molecules lead often to unfavorable changes in some important physical properties of liquid crystalline material, as a shift in the clearing temperature, for example, or can lead even to a disappearance of the mesophase. This paper presents such an event observed for the compound composed of C5H11PhPh(CH3)CN molecules, the methyl derivatives of C5H11PhPhCN molecules, which form a well-known nematic liquid crystal.
5 citations
TL;DR: In this paper, the data on temperature and concentration dependences of the direct current conductivity (σDC) of the electrolyte composed of dimethyl sulfoxide (DMSO) + ammonium nitrate (NH4NO3).
Abstract: The paper contains the data on temperature and concentration dependences of the direct current conductivity (σDC) of the electrolyte composed of dimethyl sulfoxide (DMSO) + ammonium nitrate (NH4NO3). The measurements were carried out in the whole solubility range of the nitrate in DMSO: 0 < xNH4NO3< 0.4 (x is the mole fraction) and in the temperature range from (293.15 to 333.15) K. In the isothermal conditions, the conductivity dependence on concentration shows a maximum σmax at the nitrate mole fraction xmax, and the linear dependence of σmax vs xmax was found in the studied concentration and temperature ranges. The conductivity dependence on the nitrate mole fraction in DMSO, σDC(x), was perfectly fitted with the Casteel–Amis equation.
2 citations
TL;DR: In this article, the relative static permittivities of liquids belonging to the homologous series of 1,n-dicyanoalkanes N≡C-(CH2)n-C≡N, n = 2 to 6, were determined as a function of temperature.
Abstract: The relative static permittivities of liquids belonging to the homologous series of 1,n-dicyanoalkanes N≡C—(CH2)n—C≡N, n = 2 to 6, were determined as a function of temperature. At the isothermal co...