Ferroelectric liquid crystal for use in a new generation of LCDs

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

Thin layers of a ferroelectric liquid crystal for use in a new generation of LCDs

Praca poświęcona jest badaniu nowo otrzymanego ferroelektrycznego ciekłego kryształu w celu oceny możliwości jego zastosowania jako wypełnienia w ferroelektrycznych wyświetlaczach ciekłokrystalicznych. Opisane są tekstury, sekwencja fazowa, oraz zmierzone właściwości termiczne i dielektryczne substancji. Przeprowadzone badania pozwoliły na ocenę jej potencjalnego praktycznego zastosowania.The paper concerns the research into a newly synthetised ferroelectric liquid crystal performed in order to discern the possibility of its use as a filling in a ferroelectric liquid crystal display (LCD). Described herein are the textures, phase sequence, and measured thermal and dielectric properties of the substance. Performed research allowed to issue an opinion on its potential practical use

Atomic force microscopy of ion beam-modified metal surfaces

AFM analysis of ion beam-modified metal surfaces.Praca dotyczy modyfikacji powierzchni przez bombardowanie jonowe i badania uzyskanych form powierzchniowych przy pomocy metody AFM

The Follow-up Photobioreactor Illumination System for the Cultivation of Photosynthetic Microorganisms

The article presents the basic conceptual assumptions of a photobioreactor with a complementary lighting system. The cylindrical bioreactor has three independent, interconnected, and fully controlled lighting systems. A characteristic feature is the combination of the lighting system with the measurement of photosynthetically active PAR (photosynthetically active radiation) and the optical density of the culture medium. The entire lighting system is based on RGBW (“red, green, blue, white”) LED and RBG (“red, green, blue”) LEDs. The pilot study was conducted on a simplified prototype of a photobioreactor designed for the distribution and optimization of light in algae cultures designed for energy purposes. The study was carried out on microalgae Chlorella Vulgaris BA0002a from the collection of marine algae cultures

Electro-optic and dielectric properties of new binary ferroelectric and antiferroelectric liquid crystalline mixtures

Several new binary liquid crystalline mixtures have been designed and their properties were studied by complementary methods. It has been shown that even both pure components used for the mixture design possess the ferroelectric behaviour; the induced antiferroelectric smectic phase has been detected for one of the prepared mixtures. The phase diagram has been constructed and the existence of the antiferroelectric phase was confirmed by switching time and dielectric spectroscopy measurements. Some of the resulted mixtures possess very high values of the tilt angle that reaches close below 45° degrees at saturation. Values of spontaneous polarisation were found within 50–200 nC/cm2 in dependence of the mixture’s composition. Due to specific properties, the obtained mixtures might be interesting for further design of multicomponent mixtures and formulation of the advanced nanocomposite systems

Physical properties of new binary antiferroelectric liquid crystal mixtures

Three newly prepared binary mixtures exhibiting chiral tilted smectic phases have been studied using differential scanning calorimetry, dielectric spectroscopy and electro-optic method, as well as X-ray diffraction. Broad temperature range of ferroelectric and antiferroelectric phases was detected in these mixtures and temperature dependence of spontaneous polarization, tilt angle and switching time were measured for all of them. It's occurred that all of the studied mixtures are orthoconic antiferroelectric liquid crystals. Based on the X-ray diffraction results, the temperature dependence of layer thickness in the paraelectric, ferroelectric and antiferroelectric phases was found. By using dielectric spectroscopy, Goldstone mode was identified in the ferroelectric phase, while antiphase fluctuations of azimuthal angle have been found in the antiferroelectric phase. Based on the results of the complementary methods, the transition temperatures were found as well as the order of the para-ferroelectric phase transition was determined as non-continuous one with critical parameter $\beta$ equal to ca. 0.25

Physical properties of 8OS5 thioester studied by complementary methods

Properties of 4-n-pentylphenyl-4’-n-octyloxythiobenzoate (8OS5), belonging to the nOS5 homologous series, have been studied by complementary methods. The phase sequence, the phase transition temperatures, the thickness of molecular layers, the average distance between long axes of molecules and the correlation length were determined during cooling and heating. For the first time, simultaneous X-ray diffraction and differential scanning calorimetry measurements have been used to study mesomorphic properties. The results are compared with the ones obtained in standard measurements by means of differential scanning calorimetry, X-ray diffraction and polarizing optical microscopy. Meaning of experimental procedures applied in investigations of monotropic mesophases below a melting point is discussed