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1
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Scaling in 2-d Distribution of Topological Defects in a Liquid Crystal

100%
Massalska-Arodź M.
Acta Physica Polonica A
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1998
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vol. 94
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issue 1
41-47
EN
Distribution of the topological point defects observed microscopically by Nagaya, Hotta, Orihira and Ishibashi in Schlieren texture of N-(4-n-methoxy benzylidene) 4'-n'-butylaniline has been analyzed. The same fractal dimensionality D_{f}=1.4 has been estimated for several sets of defects obtained in subsequent stages of evolution of the nematic sample after the transition from the isotropic liquid phase.
2
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Dynamics of the Molecules in Solid Phases of Few Chosen Schiff Bases Compounds

64%
Bąk A., Massalska-Arodź M.
Acta Physica Polonica A
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2004
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vol. 105
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issue 5
467-474
EN
The dielectric relaxation processes observed in solid phases of MBBA, OH-MBBA, and EBBA belonging to the homologous series of the Schiff bases are discussed. The data are compared with the results completed by the present authors for EBPA compound. The uniform interpretation of the temperature changes of relaxation for all mentioned compounds is proposed.
3
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Solid State Polymorphism and Dynamics οf 2,2-Dimethylbutan-1-ol as Studied by Adiabatic Calorimetry and Dielectric Spectroscopy

51%
Juszyńska-Gałązka E., Zieliński P., Massalska-Arodź M., Krawczyk J.
Acta Physica Polonica A
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2013
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vol. 124
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issue 6
917-925
EN
2,2-dimethylbutan-1-ol, known as neohexanol, was studied by adiabatic calorimetry and dielectric spectroscopy. Details of complex solid state polymorphism and relaxational dynamics were identified and described. System of phases of neohexanol was found to be monotropic with three orientationally disordered crystalline phases besides isotropic liquid and ordered crystal. Moreover, two subsequent glass transition anomalies of heat capacity C_{p}(T) were detected on heating in one of the supercooled orientationally disordered crystalline phases. Thermodynamical properties of neohexanol are described in relation to the dielectric relaxation processes found.
4
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Molecular Dynamics of n-p-(Ethoxybenzylidene) P'-Propylaniline in Nematic and Solid Phases as Studied by Dielectric Relaxation Spectroscopy

51%
Bąk A., Massalska-Arodź M., Urban S.
Acta Physica Polonica A
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2000
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vol. 97
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issue 2
323-330
EN
The complex dielectric permittivity ε*(ν,T) = ε'(ν,T) - iε''(ν,T) of n-p-(ethoxybenzylidene) p'-propylaniline has been measured in the frequency range from 1 Hz to 13 MHz and temperature range from 360 K to 180 K on heating and on cooling the sample. Dielectric relaxations have been found in nematic and solid phases. A detailed analysis of the observed processes has been performed and the parameters describing molecular dynamics have been evaluated. The comparison of results with those obtained for the other Schiff bases is discussed.
5
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The Solid State Polymorphism and Dynamics of 2,3-Dimethylbutan-2-ol (2,3-DM-2-B)

51%
Juszyńska E., Massalska-Arodź M., Zieliński P., Krawczyk J.
Acta Physica Polonica A
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2012
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vol. 122
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issue 4
693-697
EN
In the paper we present adiabatic calorimetry and dielectric spectroscopy results for 2,3-dimethylbutan-2-ol (2,3-DM-2-B), one of the isomers of neohexanol. For 2,3-DM-2-B we have detected the following phase transitions: C2 (249.8 K) → C1 (262 K) → Is. No glass phase was found. In both crystalline phases C2 and C1 three relaxation processes were detected. These processes are discussed in relation to the calorimetric studies.
6
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Dynamics of 4-(2-hexyloxy-ethoxy) 4'-cyanobiphenyl Molecules on Approaching a Glass Transition as Studied by Dielectric Spectroscopy

45%
Massalska-Arodź M., Witko W., Gorbachev V., Hartmann L., Kremer F.
Acta Physica Polonica A
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2003
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vol. 104
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issue 6
527-536
EN
The complex dielectric permittivity of 4-(2-hexyloxy-ethyloxy) 4'-cyano-biphenyl measured in the frequency range from 0.03 Hz to 10^9 Hz is presented. Monotropic sequence of thermodynamic phases was found with two stable phases (isotropic and crystal) and three metastable states (supercooled isotropic phase, its glass and a smectic phase observed only on heating the sample first cooled rapidly to the liquid nitrogen temperature). In isotropic and supercooled isotropic phases the temperature dependence of the dielectric relaxation time was described by the same Vogel-Fulcher-Tammann formula while in a smectic phase it was of the Arrhenius type. In the transition from a supercooled isotropic phase to a smectic phase the relaxation rate of molecular motions around the short axes increases by two decades. Comparison of the relaxation behaviour and polymorphism of 4-(2-hexyloxy-ethyloxy) 4'-cyano-biphenyl of linear molecules with two chiral cyanobiphenyls is discussed.
7
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Molecular Dynamics of 4-Cyano-3-Fluorophenyl 4-Butylbenzoate as Studied by Dielectric Relaxation Spectroscopy

45%
Massalska-Arodź M., Krawczyk J., Juszyńska E., Kocot A., Inaba A.
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issue 4
532-536
EN
Dielectric α-relaxation connected with reorientations of the 4-cyano-3-fluorophenyl-4-butylbenzoate molecules around short axes in the isotropic and nematic phases is presented. In the nematic phase the super-Arrhenius temperature dependence of the relaxation has been found. Vitrification of the supercooled nematic phase is shown. Below glass transition temperature the secondary β-relaxation has been identified and described well by the Arrhenius temperature dependence on cooling and on heating. After softening of glass to the metastable nematic phase a spontaneous crystallization occurs as for some other low-weight molecular glass formers.
8
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Studies of Phase Diagram and Glass Transitions of a Liquid Crystal with Ferro- and Antiferroelectric Phases

45%
Kolek Ł., Massalska-Arodź M., Majda D., Suchodolska B., Zalewski S.
Acta Physica Polonica A
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2013
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vol. 124
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issue 6
909-912
EN
Based on the results of the differential scanning calorimetry, of transmitted light intensity measurements and of texture observations the phase diagram of 4-(6-heptafluorobutanoiloxyhexyloxy)biphenyl-4'-carboxylate(S)-4-(methyloheptyloxy-1-carbonyl)-phenyl (4H6) was obtained. The following phases were identified on cooling: isotropic, smectic A, smectic C*, smectic C*_{A} phases and a highly ordered phase called SmX and its glass. During heating transformation from glass of SmX to SmX phase and then transition to a metastable Cr2 phase, evolving to the more stable Cr1 phase, were observed. On further heating SmC*_{A}, SmC* and Sm phases were identified. When Cr2 was cooled, a glass transition was also observed.
9
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IINS, MIR, and DFT Investigations of Vibrational Spectra of 3,3-Dimethyl-1-Butanol and 3,3-Dimethyl-2-Butanol

39%
Juszyńska E., Hołderna-Natkaniec K., Massalska-Arodź M., Natkaniec I., Ściesińska E., Ściesiński J.
Acta Physica Polonica A
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2008
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vol. 113
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issue 4
1131-1143
EN
Molecular vibrational spectra in 3, 3-dimethyl-1-butanol, (CH_3)_3 CCH_2CH_2OH, and 3, 3-dimethyl-2-butanol, (CH_3)_3CCHOHCH_3, were measured by the inelastic incoherent neutron scattering and mid infrared spectroscopy and for 3, 3-dimethyl-2-butanol additionally by the far infrared absorption method. Experimental results were discussed and compared with the results of the quantum chemical calculations performed by the density functional theory (DFT/B3LYP/6-311G**) and semi-empirical PM3 calculation methods assuming the isolated molecule approximation.
10
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Studies of New Antiferroelectric Liquid Crystal Based on Quantum-Chemical Model

39%
Tomczyk W., Marzec M., Juszyńska E., Dąbrowski R., Ziobro D., Wróbel S., Massalska-Arodź M.
Acta Physica Polonica A
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2013
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vol. 124
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issue 6
949-953
EN
Physical properties of new thermotropic antiferroelectric liquid crystal have been studied. Experiments were done by use of complementary methods such as differential scanning calorimetry, polarizing optical microscopy and X-ray powder diffractometry. Acquired data from X-ray powder diffractometry was examined under application of quantum chemical approach. It has been found that compound studied exhibits stable enantiotropic antiferroelectric SmC_{A}* phase in the wide temperature range while ferroelectric phase SmC* is very narrow.
11
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Formation of Hydrogen Bonds; Hydroxyl and Methyl Groups Dynamics in 2,2-dimethylbutan-1-ol and 2,3-dimethylbutan-2-ol: DFT, IINS and IR Investigations

39%
Juszyńska E., Hołderna-Natkaniec K., Massalska-Arodź M., Natkaniec I., Ściesińska E., Ściesiński J.
Acta Physica Polonica A
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2012
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vol. 122
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issue 4
765-775
EN
Dynamics of 2,2-dimethylbutan-1-ol and 2,3-dimethylbutan-2-ol have been studied by experimental spectroscopy methods, i.e., inelastic incoherent neutron scattering and infrared absorption. Experimental results were discussed and compared with the results of the quantum chemical calculations performed by semi-empirical PM3 and the density functional theory methods assuming the isolated molecule and dimer, trimer and tetramer clusters. The density functional theory modelling of vibrational spectra of monomers and OH bonded molecular clusters allows to assign the inter- and intermolecular vibrational modes observed in density of states and absorption spectra.
12
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Dielectric Spectroscopy Studies of 4-Cyano-3-fluorophenyl 4-Butylbenzoate Liquid Crystal at High Pressure

39%
Rozwadowski T., Massalska-Arodź M., Juszyńska E., Krawczyk J., Wojnarowska Ż., Paluch M.
Acta Physica Polonica A
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2012
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vol. 122
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issue 2
378-381
EN
For 4-cyano-3-fluorophenyl 4-butylbenzoate, nematic glassformer at ambient pressure, dielectric relaxation studies were performed under elevated pressure. In the isobaric experiment, on cooling the nematic phase two superarrhenius α-relaxations, ascribed to the reorientations of molecules around short axes and precession of long molecular axes were found and the Arrhenius β-relaxation related to intramolecular motions. Complexity of dynamics at elevated and ambient pressure is similar. Shift towards lower frequencies was found for both α-relaxations.
13
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Studies of Phase Diagram of a Liquid Crystal with 4-[2-(3-Fluorophenyl)ethyl]biphenyl Core of Molecules

39%
Kolek Ł., Massalska-Arodź M., Majda D., Wantusiak B., Zalewski S., Kula P.
Acta Physica Polonica A
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2012
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vol. 122
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issue 2
370-374
EN
Basing on the results of differential scanning calorimetry and transmitted light intensity methods and texture observations in the temperature range from - 50C to 90C phase diagram of 1-[3-fluoro-4-(1-methylheptyloxycarbonyl)phenyl]-2-[4'-(2,2,3,3,4,4,4-heptafluorobutoxybutoxy)biphenyl-4-yl]ethane was established. Monotropic system of thermodynamic phases was found. On cooling the isotropic phase transforms at 85C to ferroelectric SmC* phase and further two liquid crystalline phases, antiferroelectric SmC*_{A} and SmI, and a metastable crystal Cr2 reveal. During heating exothermic anomaly in the wide temperature range was observed and ascribed to evolution of Cr2 to the stable crystal Cr1. On further heating both SmC*_{A} and SmC* phases were observed. Thermodynamic parameters were calculated for all phase transitions. During rapid cooling (10 K/min) vitrification of metastable Cr2 crystal at T_{g} = - 115C was registered.
14
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Dynamics and Phase Transitions of 4-Bromobenzylidene-4'-pentyloxyaniline and 4-Bromobenzylidene-4'-hexyloxyaniline as Studied by Dielectric Spectroscopy

33%
Osiecka N., Massalska-Arodź M., Galewski Z., Chłędowska K., Wróbel S., Morito T., Yamamura Y., Saito K.
Acta Physica Polonica A
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2013
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vol. 124
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issue 6
913-916
EN
Significant differences in phase sequence and dynamics between 4-bromobenzylidene-4'-pentyloxyaniline (5BBA) and -bromobenzylidene-4'-heksyloxyaniline (6BBA) substances were detected by broadband dielectric spectroscopy. In the smectic A (6BBA), the smectic B (found in both substances) and the smectic E (5BBA) phases the relaxation was ascribed to reorientations of the molecules around the short axes. Slow dynamics detected in the smectic E and in two crystalline phases of 5BBA was ascribed to conformational changes of molecular chains. Coexistence of Cr(I) and Cr(II) conformationally disordered crystal (CONDIS) phases was observed and vitrification of Cr(II) was identified with help of polarizing microscopy.
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