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Wyszukujesz frazę "mesomorphism" wg kryterium: Temat


Wyświetlanie 1-4 z 4
Tytuł:
Mesogenic Dependence of Chalconyl Schiff’s Bases on Molecular Rigidity and Flexibility
Autorzy:
Pandya, S. H.
Patel, V. R.
Doshi, A. V.
Powiązania:
https://bibliotekanauki.pl/articles/1178290.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Enantiotropy
Liquid Crystals
Mesomorphism
Nematic
Smetic
Opis:
A novel homologous series R0-C6H4.CH:N-C6H4.CO.CH:CH-C6H4-OC6H13(n) of liquid crystal property is synthesized and studied with a view to understand and establish the effect of molecular structure on liquid crystal properties with respect to Schiff base and chalconyl central bridges as well as changing left n-alkoxy terminal and right n-hexyloxy fixed tail ended group. Homologous series consisted of eleven (C1 to C16) homologues in which the nematogenic mesomorphism commences from C3 homologue and continued to last C16 homologue without exhibition of smectogenic property. Rest of the C1 and C2 homologues are nonmesomorphic, whose Latent transition temperature (LTT) are predicted by extrapolation of N-I transition curves. Odd-even effect is observed for N-I transition curve. N-I transition curve and Cr-N/I transition curve behaved in normal manner. The Nematic thermal stability is 72.2 ° C. The minimum and maximum nematogenic mesophaselengths are ranging between 12.0 °C and 30.0 °C at C16 and C14 homologue respectively. Transition temperatures were determined by an optical polarizing microscopy (POM), equipped with a heating stage. Thermal analytical and spectral data confirms the molecular structures of homologues. The novel homologous series of chalconyl Schiff’s base is low melting series, whose mesogenic transition temperatures ranges between 43.0 °C and 79.0 °C.
Źródło:
World Scientific News; 2017, 86, 3; 242-252
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Synthesis, Characterization and Mesomorphic Study of new Homologous Chalcone Series
Autorzy:
Jain, B. B.
Patel, R. B.
Powiązania:
https://bibliotekanauki.pl/articles/1182886.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
liquid crystal
smectic
nematic
enantiotropic
mesomorphism
Opis:
A new designed mesogenic homologous series of chalconyl derivative with two ring α-4-Alkoxy benzoyl-β-4/-tetradecyloxy phenyl ethylenehave been synthesized and characterized by a combination of elemental analysis and standard spectroscopic methods. In series, lower members (C5 to C8) exhibit only enantiotropicnematicmesophase but higher members (C10,C12,C14,C16,C18) exhibit enantiotropicnematic as well as smecticmesophase. The nematicmesophase (Thread type) commence from C5 homologue and smecticmesophase(smectic-A type texture) commence from C10 homologue as enantiotropic and persists up to the last member synthesized. Textures are conformed by Polarizing Optical Microscope (POM). The mesomorphic properties of present series were compared with other two structurally similar series to study the effects of change of meta and para position on the mesomorphism.
Źródło:
World Scientific News; 2016, 53, 3; 241-252
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dependence of Mesomorphism on meta Substituted Lateral Groups
Autorzy:
Jain, B. B.
Patel, R. B.
Powiązania:
https://bibliotekanauki.pl/articles/1191468.pdf
Data publikacji:
2016
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Smectic
Nematic
Mesomorphism
Liquid Crystals
monotropy
Opis:
Thermotropic LC substances of chalconyl derivatives consisting of two phenyl rings, one chalconyl central bridge and two flexible {-OR and -OC7H15(n)} terminal (para) / lateral (meta) functional groups i.e. RO-C6H4-CH=CH-CO-C6H4-OC7H15(n) (meta) have been synthesized and studied for the effect of molecular structure on thermotropicmesomorphism. The thermometric behaviours of novel homologue substances and their textures were determined by an optical polarizing microscopy (POM) equipped with a heating stage. Textures of a nematic phases are threaded or schlieren. The textures of monotropicsmectic phase are directly judged from the heating top as smectic-A. Analytical, thermal and spectral data supports and conforms the molecular structures of homologues. Transition curves as depicted in a phase diagram behaves in normal manner. Odd-even effect for N-I transition curve (very short) is observed. Total (C1 to C18) thirteen homologues are synthesized .Mesomorphism commences from C7 homologue. C7 to C8 homologues are enantiotropicnematic and C10 to C18 homologues are monotropicllynematogenic plus smectogenic. Thermal stability of smectic phase is about fraction of 1.0 °C or 1.0 °C and that of nematic phase is 66.0 °C with total mesophaselength minimum to maximum 7.0 °C to 15 °C. Group efficiency order for mesophases is derived on the basis of thermal stabilities from the comparative study of thermometric data determined from structurally analogous series. Hence present novel series behaves in normal manner with very short mesophaselengths, low thermal stabilities and low melting type and predominantly nematogenic and partly smectogenic.
Źródło:
World Scientific News; 2016, 40; 199-210
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Nematogenic Mesophase Induced from Two Nonmesomorphs and Determination of LTT for Common Nonmesomorphic Component by Extrapolation
Autorzy:
Solanki, Ravindra
Patel, R. B.
Doshi, A. V.
Powiązania:
https://bibliotekanauki.pl/articles/1179586.pdf
Data publikacji:
2017
Wydawca:
Przedsiębiorstwo Wydawnictw Naukowych Darwin / Scientific Publishing House DARWIN
Tematy:
Binary System
Eutectic point
Mixed melt
Mixed mesomorphism
Nematic
Opis:
Three binary systems (A+B1, A+B2, A+B3) consisted of both admixed components as nonmesomorphs induces mesomorphic property as nematogenic mesophase within definite range of concentration of component - A. The Isotropic- Nematic (I-N) transition curves of each binary systems are extra polated to 100 mole percent of nonmesomorphic component –A to determine its reliable latent transition temperature (LTT) and to derive the group efficiency order. The common component A is a Schiff’s base, P-tolal. P’- Phenetidine (109 °C), uncommon component B1 and B2 are also Schiff’s bases p-Chloro benzal P’- chloroaniline (M.P 111.0 °C) and p-Anisal p’-Toluidine (M.P 92.0 °C) respectively, whereas, component B3 is a chalcone α- 4 methoxy phenyl β 4’-pentyloxy benzoyl ethylene (M.P 91.0 °C). The reliable predicted LTT of common component –A are 99.5 °C, 99.0 °C and 101.0 °C from binary systems A+B1 ,A+B2 and, A+B3 respectively. The group efficiency order derived is B2>B1>B3 from range of mesomorphism.The melting point of common and uncommon nonmesomorphic components are confirmed with previously reported values. Suitable magnitudes of anisotropic forces of intermolecular attractions as a consequence of resulted molecular rigidity and flexibility through respective polarity and polarizabilities of nonmesogenic components of the mesogenic mixitures which play an important role in inducing mesomorphism.
Źródło:
World Scientific News; 2017, 74; 68-79
2392-2192
Pojawia się w:
World Scientific News
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-4 z 4

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