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1

Langmuir Monolayer Characteristics of Erucylphosphocholine - A Novel Anti-Tumor Drug

100%

Wnętrzak A., Łątka K., Marzec M., Dynarowicz-Łątka P.

Acta Physica Polonica A

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2012

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vol. 121

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issue 2

468-473

EN

Erucylphosphocholine, an alkylphosphocholine anticancer drug, was employed for Langmuir monolayer characterization and liquid crystalline studies. Differential scanning calorimetry measurements together with texture observation with polarizing microscope revealed the presence of nematic phase. Film forming properties of erucylphosphocholine at the air/water interface were thoroughly investigated by means of surface pressure-area (π-A) and electric surface potential-area (Δ V-A) isotherms. The influence of such factors as subphase temperature, ionic strength, speed of compression, number of molecules spread at the surface on the characteristics of the π-A isotherms was investigated. Erucylphosphocholine was found to form very stable Langmuir monolayers, which are almost not influenced by experimental conditions. The liquid character of its monolayers was confirmed with both compressibility modulus values and homogeneous Brewster angle microscopy images.

2

Ferroelectric Liquid Crystal for Use in a New Generation of LCDs

88%

Fitas J., Marzec M., Tykarska M., Wróbel S., Dąbrowski R.

Acta Physica Polonica A

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2013

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vol. 124

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issue 6

954-958

EN

The key to improvements in liquid crystalline displays lies in the continuous synthesis and studies of new kinds of liquid crystalline substances. Among them, ferroelectric compounds are the subject of much attention, due to the potential progresses in switching time, colour depth, and other qualities of liquid crystal displays. In this paper we describe the research of the physical properties of 4-(2-methylbutoxy)phenyl 4-(octyloxy)-benzoate for purposes of its potential application in liquid crystal displays.

3

Influence of Experimental Conditions on Deposition of Silver Nanoparticles Onto Surface of Graphene Oxide / Wpływ Warunków Eksperymentalnych Na Proces Osadzania Nanocząstek Srebra Na Powierzchni Tlenku Grafenu

88%

Mech K., Wojnicki M., Mania I., Gajewska M., Marzec M.

Archives of Metallurgy and Materials

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2015

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issue 4

4

Studies of New Antiferroelectric Liquid Crystal Based on Quantum-Chemical Model

76%

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.

5

Dielectric and Conductivity Anisotropy in Liquid Crystalline Phases of Strongly Polar Thioesters

76%

Mikułko A., Fraś M., Marzec M., Wróbel S., Ossowska-Chruściel M., Chruściel J.

Acta Physica Polonica A

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2008

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vol. 113

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issue 4

1155-1160

EN

The main objective of this paper is to study dielectric properties of two compounds of acronyms 5OSCl and 6OSCl having strongly polar bond (C-Cl) at para position. Dielectric measurements were done in the frequency range from 40 Hz to 15 MHz. The dielectric spectra were measured for two principal alignments. For homeotropic alignment, the reorientation of molecule around the short molecular axis was observed. Both substances studied exhibit large positive dielectric anisotropy and the anisotropy of conductivity was obtained in smectic A as well as nematic phase.

6

Dielectric and Electrooptic Investigations of B Phases οf Banana-Shaped Thioesters

64%

Wierzejska-Adamowicz M., Ossowska-Chruściel D., Chruściel J., Douali R., Legrand C., Marzec M., Mikułko A., Sikorska A., Wróbel S.

Acta Physica Polonica A

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2010

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vol. 117

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issue 4

557-561

EN

Electrooptic and dielectric measurements were done for B phases of two banana-shaped homologues 1,3-phenylene bis{4-[(4-nonylo-xy-benzoyl)sulfanyl]benzoate (9OSOR) and 1,3-phenylene bis{4-[(4-dodecylo-xy-benzoyl)sulfanyl]benzoate (12OSOR). Polarizing microscopy allowed to identify B_{1} phase for 9OSOR and B_{2} phase for 12OSOR on the basis of texture observation. Spontaneous polarization measurements were performed using reversal current method. The current response to applied triangular voltage shows that B_{1} phase is a ferroelectric and B_{2} phase - antiferroelectric one for which two well separated peaks were observed. Polarization for phase B_{1} of 9OSOR is rather small and its temperature dependence is unusual for ferroelectric liquid crystals - it increases with temperature. Spontaneous polarization for B_{2} phase of 12OSOR compound is of about 600 nC/cm^{2}. Dielectric spectra measured with bias field for B_{2} phase of 12OSOR show two well separated relaxation processes. In the low frequency range the relaxation process is connected with fluctuations of ferroelectric domains. The relaxation process in the high frequency range appearing also without bias field is connected with molecular reorientation. The dielectric spectra measured for B_{1} phase of 9OSOR with and without bias voltage showed only one dielectric relaxation process connected with molecular reorientation around the short axis.

7

Rehydration of CTMA Modified DNA Powders Observed by NMR

64%

Harańczyk H., Kobierski J., Zalitacz D., Nowak P., Romanowicz A., Marzec M., Nizioł J., Hebda E., Pielichowski J.

Acta Physica Polonica A

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2012

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vol. 121

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issue 2

485-490

EN

The rehydration of salmon sperm deoxyribonucleic acid (DNA) and cetyltrimethylammonium chloride (C_{19}H_{42}ClN) complexes was observed using hydration kinetics, sorption isotherm, and high power proton relaxometry (at 30 MHz). The hydration kinetics shows (i) a very tightly bound water not removed by incubation over silica gel (A_0^{h} = 0.061 ± 0.004), (ii) a tightly bound water saturating at A_1^{h} = 0.039 ± 0.011, with the hydration time t_1^{h} = (1.04 ± 0.21) h, a loosely bound water fraction (iii) with the hydration time t_2^{h} = (19.1 ± 3.2) h and the contribution progressively increasing with the air humidity. For the hydration at p/p_0 = 100%, after t_0 = (152.6 ± 2.5) h of incubation the swelling process begins. The swelling time was t_3^{h} = (12.5 ± 5.4) h, and the swelling amplitude A_3^{h} = 0.140 ± 0.016. The sorption isotherm is sigmoidal in form and is fitted by the Dent model with the mass of water saturating primary binding sites Δ M/m_0 = 0.102 ± 0.021. Proton free induction decay is a superposition of the immobilized proton signal (Gaussian, with T_{2S}* ≈ 30 μs) and two liquid signal components coming from tightly bound (T_{2 L_1}* ≈ 100 μs) and loosely bound water fraction with the amplitude proportional to the mass of water added (T_{2 L_2}* ≈ 1000 μs).

8

Polymorphism of Chiral Thioester Studied by Dielectric Spectroscopy

52%

Wawrzyniak A., Chruściel J., Douali R., Dubois F., Leblond J., Legrand C., Ossowska-Chruściel D., Marzec M., Ropa P., Czerwiec J., Wróbel S.

Acta Physica Polonica A

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2013

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vol. 124

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issue 6

933-936

EN

(S)-(+)-4'-[(4-(1-methylheptyloxycarbonylphenyl) thiocarbonylphenyl]-decyloxybenzoate (in short 10.OPOSMH) was studied by complementary methods. The substance shows rich polymorphism. In addition to ferroelectric and antiferroelectric smectic C* phases it possesses three ferrielectric sub-phases. Phase transitions between the phases were revealed by differential scanning calorimetry and static dielectric permittivity measurements. The aim of this paper was to study phase transitions and differences in dielectric spectra shown by different phases. Collective and molecular dynamics of all phases shown by 10.OPOSMH will be discussed in terms of theoretical models. Dielectric spectra of antiferroelectric phase show two characteristic dielectric relaxation modes: one connected with the molecular process (reorientation around the short axis) and the other originating from fluctuations of antiferroelectric order parameters.

Refine search results

Langmuir Monolayer Characteristics of Erucylphosphocholine - A Novel Anti-Tumor Drug

Ferroelectric Liquid Crystal for Use in a New Generation of LCDs

Influence of Experimental Conditions on Deposition of Silver Nanoparticles Onto Surface of Graphene Oxide / Wpływ Warunków Eksperymentalnych Na Proces Osadzania Nanocząstek Srebra Na Powierzchni Tlenku Grafenu

Studies of New Antiferroelectric Liquid Crystal Based on Quantum-Chemical Model

Dielectric and Conductivity Anisotropy in Liquid Crystalline Phases of Strongly Polar Thioesters

Dielectric and Electrooptic Investigations of B Phases οf Banana-Shaped Thioesters

Rehydration of CTMA Modified DNA Powders Observed by NMR

Polymorphism of Chiral Thioester Studied by Dielectric Spectroscopy