256 results on '"mesophases"'
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2. Landau-de Gennes theory of the nematic to smectic—A phase transition under confinement conditions.
- Author
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Mukherjee, Prabir K.
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PHASE transitions , *SMECTIC liquid crystals , *TRANSITION temperature , *MESOPHASES , *PHASE diagrams , *ENTHALPY , *LIQUID crystals - Abstract
We study the nature of the nematic to smectic-A phase transition under confinement conditions in the context of Landau-de Gennes theory. The effect of quenched disorder on the nematic to smectic-A transition temperature, order parameter, enthalpy, and thermal hysteresis are discussed followed by phase diagrams. The tricritical behavior of the nematic to smectic-A phase under confinement conditions is predicted. [ABSTRACT FROM AUTHOR] more...
- Published
- 2023
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3. Preliminary study on the self-assembly of a pair of azobenzene liquid crystals derived from alanine.
- Author
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Wu, Limin, Chu, Jinming, Wang, Fei, Liu, Wei, Guo, Yongmin, Li, Yi, Li, Baozong, and Yang, Yonggang
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LIQUID crystals , *MESOPHASES , *ALANINE , *AZOBENZENE , *AMINO acid residues , *CIRCULAR dichroism - Abstract
A series of azobenzene liquid crystals containing one amino acid residue were synthesized. They exhibit smectic mesophases. The compounds derived from alanine can self-assemble into twisted nanoribbons. The molecules organized in a monolayer structure within the nanoribbon. Circular dichroism characterization indicated that the neighboring liquid crystal cores packed in a chiral structure. FT-IR spectra indicated that the nanoribbons were caused by H-bonding and association of hydrocarbon chains. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
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4. Polar cyano/nitrile group-derived rod-shaped nematic liquid crystals: synthesis and characterizations†.
- Author
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Srinivasa, H. T.
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NEMATIC liquid crystals , *MESOPHASES , *ELEMENTAL analysis - Abstract
The cyano/nitrile group-derived calamitic molecules are synthesized and characterized for the search of pure nematic phase. The chemical structures were confirmed using standard spectroscopic techniques such as IR, NMR, and elemental analysis. Mesophases were analyzed and characterized by the combination of POM, DSC, and X-ray analysis methods. Most of the compounds show nematic mesophases with moderate transition ranges. Further detailed studies may leads to special nematics like uniaxial/biaxial nematic, twist-bent nematic and cybotactic nematic mesophases. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
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5. Polar cyano/nitrile group-derived rod-shaped nematic liquid crystals: synthesis and characterizations†.
- Author
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Srinivasa, H. T.
- Subjects
NEMATIC liquid crystals ,MESOPHASES ,ELEMENTAL analysis - Abstract
The cyano/nitrile group-derived calamitic molecules are synthesized and characterized for the search of pure nematic phase. The chemical structures were confirmed using standard spectroscopic techniques such as IR, NMR, and elemental analysis. Mesophases were analyzed and characterized by the combination of POM, DSC, and X-ray analysis methods. Most of the compounds show nematic mesophases with moderate transition ranges. Further detailed studies may leads to special nematics like uniaxial/biaxial nematic, twist-bent nematic and cybotactic nematic mesophases. [ABSTRACT FROM AUTHOR] more...
- Published
- 2022
- Full Text
- View/download PDF
6. Liquid crystal behavior of Ag(I) complexes based on a series of mesogenic 1,3,4-thiadiazole ligands.
- Author
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Tomi, Ivan Hameed R., Al-Karawi, Ahmed Jasim M., OmarAli, Al-Ameen Bariz, and Al- Heetimi, Dhafir T. A.
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MESOPHASES , *LIQUID crystals , *THIADIAZOLES , *POLARIZATION microscopy , *MOLAR conductivity , *LIGANDS (Chemistry) , *ORGANIC compounds - Abstract
2-(4-Alkoxyphenyl)-5-(p-tolyl)-1,3,4-thiadiazoles (alkoxy: O(CH2)nH, n = 1–8) (6a–h) (as a series of 1,3,4-thiadiazole derivatives) and their silver(I) complexes: bis(2-(4-alkoxyphenyl)-5-(p-tolyl)-1,3,4-thiadiazole)-silver(I) complexes (alkoxy: O(CH2)nH, n = 1–8) (7a–h) were prepared and characterized with different techniques: microelemental analysis, FTIR, UV–Vis, 1H NMR, 13C NMR and mass (for the organic compounds) spectra, in addition to the molar conductivity measurements (for Ag(I) complexes). Liquid crystal behavior of the two series of compounds was evaluated using polarized light optical microscopy (POM). The study revealed that both series are enantiotropic liquid crystalline materials (exhibiting wide mesomorpic temperature ranges) with different behavior and properties. 6a–f displayed only nematic mesophase upon heating and cooling, while 6g and 6h exhibited both of SmC and nematic mesophases upon heating and cooling. Upon complexation of 1,3,4-thiadiazoles (6a–h) to silver(I), the liquid crystal behavior and properties are significantly changed (different mesophases, and lower mesophase and clearing temperatures). However, 7b–h exhibited SmA mesophase upon heating and cooling, while 7a shows no mesomorphic properties (simply melted to isotropic liquid). [ABSTRACT FROM AUTHOR] more...
- Published
- 2021
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7. Influence of molecular architecture, hydrogen bonding, chemical moieties and flexible chain for smectic polymorphism in (4)EoBD(3)AmBA:nOBAs.
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Krishna Murthy, A. V. S. N., Srinivasulu, M., Madhumohan, M. L. N., Muni Prasad, M., Rao, Y. V., Ashok Kumar, A. V. N., Chalapathy, P. V., and Potukuchi, D. M.
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HYDROGEN bonding , *SCHIFF bases , *PHASE transitions , *ORDER-disorder transitions , *DIFFERENTIAL scanning calorimetry , *MOIETIES (Chemistry) , *SMECTIC liquid crystals , *MESOPHASES - Abstract
A novel series of calamitic, complementary hydrogen-bonded (HB), meta-extended Schiff base core containing liquid crystalline (LC) complexes with ethoxy chain at one end and varied flexible chain at other end, viz., (4)EoBD(3)AmBA:nOBAs for n = 3–12 is reported. 1H, 13C NMR and FTIR spectroscopy confirm complex formation. LC phases, phase transition temperatures (TC) and enthalpy are characterized by polarizing optical microscopy and differential scanning calorimetry(DSC). SmA, SmC, SmBcryst,SmF, SmI, SmE, SmG and SmH phases are exhibited. Clearing and melting temperatures exhibit odd–even effect. Schiff base bridged by oxygen atom promoted of smectic phase occurrence. Complementary HB-induced and -enhanced tilted smectic phase range. Large LC phase variants, i.e., tetra, penta and hexa are observed. Hexa LC phase variant for n = 6 and 12. Unlike in p-n-alkoxy benzoic acids (nOBAs), Nematic phase is quenched. Quasi two-dimensional LC SmF and SmI phases identified. Lower (for n = 3,5), intermediate (for n = 6,7) and higher (n = 9) homologues exhibit 3D SmBcryst phase. Monotropic LC phase occurrence is also noticed. Apart from other LC phase transitions, SmA–SmC transition is mostly found to be second order or very weakly first order nature. Phase diagram by DSC infers existence of multi-critical points in the vicinity of SmF and SmI phase structures with psuedo hexagonal packing. Influence of meta-extended core, complementary HB and flexibility component are discussed for LC phase abundance. Role of orientational disorder induced by flexible component discussed. In comparison with LC phase occurrence in (4)MeoBD(3)AmBA:nOBAs, shielded inductomeric effect is argued for large thermal range of tilted smectic phases. Integrated and differential heat energies are estimated in successive heating and cooling scans to investigate optimized realization of LC phases. Results are discussed in the wake of contemporary reports in other LCs. [ABSTRACT FROM AUTHOR] more...
- Published
- 2021
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8. Binary systems of non-mesogens with naphthalene derivatives.
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Yao, Yong fang, Patel, H. N., Prajapati, Ashish Kumar, Sangani, Chetan B., and Duan, Yong-Tao
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BINARY mixtures , *MESOPHASES , *NAPHTHALENE derivatives - Abstract
Binary mixtures with both the components are non-mesogenic becomes an interesting and enlighten feature when they exhibit mesomorphism at ambient temperature. In the present study, we report five binary systems where two non-mesogenes exhibit smectic and/or nematic mesophases at ambient temperature over a certain range of concentration. All the binary systems contain one non-mesogenic naphthalene derivative. The study provides many binary systems of non-mesogens which exhibit mesophases at ambient temperatures. The terminal nitro chain is found to be responsible for the induction of both the nematogenic and smectogenic tendency in the present investigation of binary systems with two 'compatible' component. [ABSTRACT FROM AUTHOR] more...
- Published
- 2020
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9. Studies on thermotropic hydrogen bonded binary mixtures.
- Author
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Rohini, P., Pongali Sathya Prabu, N., and Madhu Mohan, M.L.N.
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HYDROGEN bonding , *BINARY mixtures , *PALMITIC acid , *BENZOIC acid , *THERMAL properties , *OPTICAL properties - Abstract
The precursors of the present thermotropic hydrogen bonded binary mixtures investigated are prepared from Palmitic acid (PA) and p,n- alkyloxy benzoic acids. PA + 8BAO complex is chosen as one of the chemical ingredients referred as X and PA + 11BAO & PA + 12BAO are referred as Y ingredients to obtain binary mixtures as the individual complexes possesses rich phase polymorphism. As a result, two sets of binary mixtures are formed that is PA + 8BAO: PA + 11BAO and PA + 8BAO: PA + 12BAO which yielded nine binary mixtures of former and later in molar proportion from 0.1 to 0.9. Optical and thermal properties of eighteen binary mixtures are extensively studied. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
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10. Identification of low-symmetry phases in nematic liquid crystals.
- Author
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Turzi, Stefano S. and Bisi, Fulvio
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NEMATIC liquid crystals , *LIQUID crystal states , *SYMMETRY groups , *LIQUID crystals , *MESOPHASES - Abstract
Mesophases of nematic liquid crystals (NLC) are traditionally identified by building a second-rank ordering tensor that efficiently describes the average orientation of nematogenic molecules with respect to a fixed laboratory/reference frame. In general, both in experiments and in simulations, the symmetry group of the molecules is known a-priori, contrary to the symmetry group of the phase; this latter has to be determined by analysing the numerical realisation of possibly affected by numerical errors. Furthermore, when a mesophase has a simple symmetric structure, as is the case of uniaxial nematics, the identification of the preferred direction is relatively an easy task. However, this task becomes less straightforward when the symmetry group of a mesophase is more complex. There is no generally accepted procedure to perform this analysis, but we have provided in a previous paper a new algorithm suited to identifying the symmetry group of the phase. We implement here such algorithm which gives a canonical representation of for each of the classes that can be distinguished with a second-rank ordering tensor, and determines the nearest tensor of the assigned symmetry by group averaging. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
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11. Evolution of Anisotropy, First Order Hyperpolarizability and Electronic Parameters in p-Alkyl-p'-Cynobiphenyl Series of Liquid Crystals: Odd-Even Effect Revisited.
- Author
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Kumar, Abhishek, Srivastava, Ambrish Kumar, Tiwari, Sugriva Nath, Misra, Neeraj, and Sharma, Dipendra
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LIQUID crystals , *MESOPHASES , *ANISOTROPY , *ELECTRON affinity , *IONIZATION energy , *TRANSITION temperature - Abstract
The homologues of p-alkyl-p'-cynobiphenyl (nCB) liquid crystal series are widely known for their diverse applications in display device industries, due to the low transition temperature. The transition temperature dependence on the number of carbon atoms in the alkyl chain, associated at one end of nCB series is commonly referred to as 'the odd-even effect', which is widely reported for the nematic zone (n ≤ 8). Herein, we perform a theoretical study on the odd-even effect in the homologues of nCB series for n = 1-12 using density functional based calculations at B3LYP/6-311++G(d,p) level. We have calculated electro-optical parameters such as the dipole moment, polarizability, anisotropy and hyperpolarizability along with some electronic parameters such as ionization potential, electron affinity, chemical hardness and absolute electronegativity of nCB mesogenic series. The variation of these parameters suggests that the odd-effect in nCB homologues is not only confined to nematic zone but also extended to smectic zone (n > 8) at the molecular level, except the variation of electron affinity which indeed suggests that the odd-even effect is limited to nematic zone. This study may offer better insights into properties of homologues of nCB and similar compounds at the molecular level. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
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12. Chiral liquid crystals: Synthesis and characterization for thermal and mesomorphic properties.
- Author
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Srinivasa, H. T.
- Subjects
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LIQUID crystals , *THERMAL properties , *POLYMER liquid crystals , *MESOPHASES , *CHEMICAL structure - Abstract
In this work, we are presenting synthesis, characterization and their mesomorphic properties of some new calamatic shaped liquid crystal molecules with chiral centre. The chiral centre was fixed at one end of the molecule and other end was modified by various alkyl substituents. Most of the molecules showing wide range of smectic A, nematic and ferroelectric SmC* mesophases enantiotropically. Chemical structures were established by IR, NMR and their mesophase behaviours by DSC, POM and X-ray instrumentations. [ABSTRACT FROM AUTHOR] more...
- Published
- 2019
- Full Text
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13. "Dependence of Mesomorphism in Combination with Fluoro and Chloro Groups".
- Author
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Ranchchh, Avani R., Tharesha, Bhavna R., and Bhoya, U.C.
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MESOPHASES , *CINNAMIC acid , *MASS spectrometry , *ESTER derivatives , *MOLECULAR structure , *TRANSITION temperature - Abstract
A novel azoester homologous series with chloro lateral group and a fluoro terminal end group was synthesized and characterized for mesomorphic properties. It consists of thirteen azo ester derivatives from trans-4-n-alkoxy cinnamic acid with 4-hydroxy-3-chloro phenyl azo-3-chloro-4-fluoro benzene. Mesomorphic property commences from C4homologue as smectic.C1 to C3 member of the series are non-mesomorphic. C4 to C18 homologous are enantiotropic smectic A phase. The nematic mesophase is totally absent. Texture and transition temperatures of the homologues are determined by an optical polarizing microscopy equipped with heating stage. 1H NMR, IR spectra, mass spectra, of some member is included. The spectroscopic analysis supports the molecular structure. A phase diagram is used to illustrate the mesomorphic behaviour across the series. Mesophaselength for smectic is varying from18.0°C to 69.00C. Mesomorphic properties of the novel azoester series are compared with structurally similar series. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
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14. Theoretical and experimental studies on optically tunable hydrogen bonded liquid crystal complex derived from mesogenic and non-mesogenic aromatic compound.
- Author
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Ramya, A., Jayaprakasam, R., Chitravel, T., and Vijayakumar, V. N.
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MESOPHASES , *LIQUID crystals , *LIQUID hydrogen , *HYDROGEN bonding , *AROMATIC compounds , *COMPLEX fluids - Abstract
A novel hydrogen bonded liquid crystal (HBLC) complex is synthesized from non-mesogenic benzylmalonic acid (BMA) and mesogenic 4-nonyloxybenzoic acid (9OBA). Structural properties and optimized vibrational frequencies of BMA + 9OBA have been studied by FT-IR spectrum. The weak intermolecular interaction between the molecules is proved by NBO and Mulliken charge distribution analysis. The optical and thermal properties are investigated by POM, DSC, UV-Visible and PL techniques. The present HBLC complex exhibits schlieren textures of nematic, broken focal conic texture of smectic C and multicolored mosaic texture of smectic G phases respectively which is not observed in the pure mesogen (9OBA). The HBLC complex geometry is optimized by DFT method at the level of B3LYP basis set 6311G (d, p). The electronic properties of HBLC complex such as, NBO, HOMO-LUMO, ESP and Mulliken charge distribution are also studied. A noteworthy observation is brought out by identifying the presence of photoluminescence in nematic phase due to the variation in intermolecular interaction of the mesophase. The utility of the same complex is discussed. The phase width, thermal stability factor, tilt angle, phase transition temperature and its enthalpy values are reported. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
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15. Synthesis and Mesogenic Properties of Liquid Crystals Based on Cholesterol and Cinnamic Acid Derivatives.
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Zong, Xuenan and Wu, Changcheng
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CHEMICAL synthesis , *MESOPHASES , *CINNAMIC acid , *CHOLESTERIC liquid crystals , *THERMAL stability , *SMECTIC liquid crystals - Abstract
A group of new mesomorphic compounds with cholesterol-based, which have derivative of the cinnamic acid, with different lengths of terminal alkoxy chains, are synthesized and characterized. The mesomorphic properties were investigated by DSC and POM. All target compounds showed a cholesteric phase. For 12-TC and 14-TC besides a cholesteric phase, also revealed a SmA* phase. The experimental results demonstrated that with the increase in the terminal chain lengths, the thermal stability of the smectic mesophases of these liquid crystals was increased, and these compounds shows brilliant color changes in the temperature ranges of cholesteric phase. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
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16. Mesomorphism dependence on molecular rigidity and flexibility.
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Ranchchh, Avani R. and Bhoya, U. C.
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LIQUID crystal synthesis , *MOLECULAR structure , *MESOPHASES , *THERMAL stability , *POLARIZATION microscopy - Abstract
A novel homologous series of liquid crystalline properties is synthesized and studied with a view to understand the effect of molecular structure on its thermotropic properties. Novel homologous series consisted of thirteen homologs. All the homologs are enantiotropically smectogenic with absence of nematic property even in the monotropic condition. Textures of the homologs as observed through an optical hot stage polarizing microscopy. The mesophase temperature range vary minimum from 6.0°C to a maximum 37.0°C at the methyloxy and propyloxy derivatives of a series respectively with its thermal stability (Sm-I) 127.0°C. Transition curves of a phase diagram behaved in normal manner. Odd-even effect is observed for Sm-I transition curve. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
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17. Refracting properties of lyotropic nematic calamitic mesophase under magnetic field.
- Author
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Yavuz, Aykut Evren
- Subjects
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MESOPHASES , *REFRACTIVE index , *NEMATIC liquid crystals , *MAGNETIC fields , *BIREFRINGENCE - Abstract
The present study found the time-dependent extraordinary refractive index and birefringence of lyotropic nematic calamitic mesophase for different temperatures during its orientation under magnetic field. Based on the experimental results, the average angle between the mesophase directors and magnetic field was calculated to estimate the orientation dynamics of the mesophase during the director rotation from planar to homeotropic orientations. On the other hand, the textural properties were investigated during the orientation. The ordinary and extraordinary refractive indices were also measured depending on temperature to obtain the orientational order parameter of the mesophase. Using the macroscopic refractive index results, the microscopic polarizability was studied as well. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
- Full Text
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18. X-ray diffraction study of mesogenic 4-methoxyphenyl-4'-n-nonyloxybenzoate.
- Author
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Kuz'mina, L. G., Churakov, A. V., and Konstantinov, I. I.
- Subjects
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X-ray diffraction , *GUAIACOL , *LIQUID crystals , *BENZOATES , *MESOPHASES , *STACKING interactions , *HYDROGEN bonding - Abstract
4-methoxyphenyl-4'-n-nonyloxybenzoate have been investigated by single crystal X-ray structural analysis. Crystal packing of the compounds does not represent a precursor of the mesophse although the typical for liquid crystal compounds separation of crystal packing on aromatic and aliphatic areas is observed here. Possible reason for monotropic properties are discussed. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
- Full Text
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19. Study of Y-shaped liquid crystalline materials with polar nitro substituent.
- Author
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Dixit, Sandhya
- Subjects
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POLYMER liquid crystals , *LIQUID crystal displays , *MESOPHASES , *MOLECULAR shapes , *PHOTOISOMERIZATION , *PHOTOCHROMIC materials - Abstract
A new homologous series of Y-shaped liquid crystals namely 4-Nitro-[2'4'bis (4"-n-alkoxybenzoyloxy)] phenyl bisazobenzenes have been synthesized and its thermotropic properties studied on the hot stage of a polarizing microscope. The compounds consist four phenyl rings joined through ester and bisazo linkages with alkoxy and nitro as terminal substituents. The structures of synthesized compounds were confirmed by spectroscopic techniques such as FTIR, HNMR as well as elemental analysis. The compounds were found to exhibit enantiotropic nematic and smectic mesophases. The role of molecular shape, size and polarity of functional groups in the mesophases formation is discussed. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
- Full Text
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20. Photo-current measurements of liquid crystal cells to clarify the mechanism of flicker drifts.
- Author
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Nagano, Yasutomo, Huang, Ming-Hung, and Huang, Wen-Fu
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LIQUID crystals , *MESOPHASES , *ELECTRIC potential , *IONS , *PHOTOCURRENTS - Abstract
We performed photo-current experiments on various liquid crystal (LC) cells, and compared with the results of conventional evaluations of reliability of LC display (LCD) such as voltage holding ratio (VHR), ion density, and flicker. The accumulated charges in LC cells were estimated by the time integration of photo-currents. Good correlations among observed photo-current, estimated charges, and flicker drift were obtained, which revealed that the accumulated charges in LC cells are one of the major factors to cause the flicker drift. [ABSTRACT FROM AUTHOR] more...
- Published
- 2018
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21. Tris ( N -phenyltriazole) derivative – New compound with star shaped anisometry and discotic liquid crystals behavior.
- Author
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Ratto, Carlos, Westphal, Eduard, de Campos, Carlos Eduardo Maduro, and Gallardo, Hugo
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DISCOTIC liquid crystals , *LIQUID crystal synthesis , *MESOPHASES , *LIQUID crystal states , *SYNCHROTRON radiation , *X-ray diffraction , *NUCLEAR magnetic resonance - Abstract
In this article, we present the synthesis, structural characterization, thermal and photophysical studies of the first derivative of thetris-(N-phenyltriazole) core presenting liquid crystalline properties. The compound presents a star shaped anisometry with 6 long alkoxy chains (C12) and shows a short range monotropic columnar hexagonal mesophase, as confirmed by polarized optical microscopy, differential scanning calorimetry and X-ray diffraction measurements using synchrotron radiation. The molecular structure and purity were confirmed by1H and13C nuclear magnetic resonance and high resolution mass spectrometry, while thermogravimetric analysis indicate good thermal stability. The photophysical investigation of the target compound in chloroform solution shows strong blue emission (maximum at 420 nm) with high luminescence relative quantum yield (72%). [ABSTRACT FROM PUBLISHER] more...
- Published
- 2017
- Full Text
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22. Effect of dicationic ionic liquids on lyotropic liquid crystals formed by a binary system composed of Triton-X 100 and water.
- Author
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Thieghi, Leila T., Longo, Luiz S., Licence, Peter, and Alves, Sarah
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LYOTROPIC liquid crystals , *IONIC liquids , *MESOPHASES , *LIQUID crystal states , *PHASE diagrams , *GAS chromatography , *TRANSITION temperature , *SMALL-angle X-ray scattering - Abstract
In this work, binary mixtures of a non-ionic surfactant (Triton X-100) and water were studied with concentrations of 30%wt H2O, showing, lamellar mesophase at temperatures below 10oC. Different dicationic ionic liquids were used for doping these mesophases: 1,n-bis(3-methylimidazolium-1-yl)alkane, 1,n-bis(1-methylpyrrolidinium-1-yl)alkane and 1,n-bis(pyridinium-N-yl)alkane dibromide, where n = 6 and 8. Polarized Optical Microscopy and Small-Angle X-ray Scattering were used for identifying the mesophases and the influence of different dicationic ionic liquids on the lyotropic liquid crystals phase transitions. The addition of dicationic ionic liquids to the lyotropic liquid crystals samples led to changes in transition temperature and in mesophase structure itself (such as characteristic distances). [ABSTRACT FROM PUBLISHER] more...
- Published
- 2017
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23. Synthesis and mesomorphic behavior of symmetrical chiral liquid crystal dimers incorporating ester linked biphenyl- naphthyl cores and terminal vinyl group.
- Author
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Viswanath, Lakshmi C. Kasi and Senthil, Sengodan
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LIQUID crystal synthesis , *DIMERIZATION , *MESOPHASES , *NAPHTHYL compounds , *VINYL polymers , *CHEMICAL precursors , *CHIRALITY - Abstract
A series of symmetrical chiral, liquid crystal dimeric molecules possessing ester- linked, biphenyl-naphthyl cores with varied spacer lengths and terminal vinyl groups have been synthesized using Naproxen as the synthetic precursor. The synthesized symmetrical chiral dimers were characterized by 1H NMR spectroscopy, and their liquid crystalline behavior was confirmed by DSC and HOPM studies. Structural effects on the mesomorphic and physicochemical properties were investigated in terms of variation of chiral chain length. The synthesized dimeric compounds exhibited SmX*, SmC*, SmA*, N*, BPI*, and BPII*mesophase sequences. An odd-even effect was observed in the dimers and the duration of the mesophase decreased with increasing spacer length. The synthesized vinyl substituted liquid crystalline dimers are particularly useful in understanding liquid crystal polymorphism and act as model compounds for liquid crystal polymers. [ABSTRACT FROM PUBLISHER] more...
- Published
- 2017
- Full Text
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24. Synthesis and characterization of rigid rode shape homologous series: Effect of tail iodo group.
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Sharma, Vinay S., Sharma, Anuj S., and Patel, R. B.
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CHEMICAL synthesis , *MESOPHASES , *CHALCONE synthase , *BENZOIC acid , *DIFFERENTIAL scanning calorimetry , *THERMAL stability - Abstract
In this study, the synthesis, structural characterization and mesomorphic properties of newly thirteen calamitic rod-shaped compounds derived from chalcone and 4-n-alkoxy benzoic acid. Here we present, chalcone as central group and terminal side substituted iodo (−I) group containing homologous series. Comp.C1displayed nonmesogenic nature, while comp.C3to comp.C18shows enantiotropic smectic plus nematic property except comp.C2which show only nematic phase. It is shown that chalcone as central linking unit favors a calamitic liquid crystalline behaviour in molecules. Phase transition temperatures of present synthesised compounds were determined by optical polarising microscopy (POM), differential scanning calorimetric (DSC). Thermal stabilities for smectic and nematic mesophases are 150.18 and 163.58 respectively. [ABSTRACT FROM PUBLISHER] more...
- Published
- 2017
- Full Text
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25. Analysis of optical and thermal properties of double hydrogen bonded liquid crystal binary mixtures.
- Author
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Rajanandkumar, R., Prabu, N. Pongali Sathya, and Mohan, M. L. N. Madhu
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HYDROGEN bonding , *LIQUID crystals , *MICROSCOPY , *DIFFERENTIAL scanning calorimetry , *MESOPHASES - Abstract
Eighteen binary mixtures are prepared from three thermotropic double hydrogen bonded liquid crystal complexes formed by Mesaconic Acid (ME) and various alkyloxy benzoic acids, namely ME + 5BAO, ME + 11BAO and ME + 12BAO where 5BAO, 11BAO and 12BAO represents pentyloxy benzoic acid, undecyloxy benzoic acid and dodecyloxy benzoic acid respectively. Two sets of binary mixtures (ME + 12BAO with ME + 5BAO and ME + 11BAO with ME + 5BAO) are formed by varying their molar ratio in steps of 0.1 to 0.9 which leads to the formation of eighteen binary mixture complexes. Existence of different energy bands in the binary mixtures is identified from the analysis of Fourier Transform Infrared Spectroscopy (FTIR). Phases such as nematic and smectic C are observed in all the binary mixtures which are confirmed through Polarizing Optical Microscopy (POM). Transition temperatures corresponding to the individual mesophases are further verified using Differential Scanning Calorimetry (DSC). Phase diagram of two sets of binary mixtures are constructed with the aid of POM and DSC data. Optical tilt angle measurement; a primary order parameter; is calculated in smectic C phase of the binary mixtures and the resultant data obtained is fitted to critical exponent value is in concurrence with the Mean Field theory predicted value. Thermal studies such as stability factor, order of phase transitions and specific heat capacity value of the mesophases are extracted from the DSC thermograms. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
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26. New hockey stick shaped amino allylidene (‒N˭CH‒CH˭CH) based compounds: Effect of linkage group on mesomorphic properties.
- Author
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Sharma, Vinay. S., Vekariya, Rajesh. H., Sharma, Anuj. S., and Patel, R. B.
- Subjects
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MESOPHASES , *LIQUID crystals , *PHENYL compounds , *CHEMICAL synthesis , *BENZOATES , *NEMATIC liquid crystals - Abstract
Two nonlinear hockey stick shaped homologous series based on three linking groups have been synthesized and characterized by elemental analyses and spectroscopic techniques. The mesomorphic properties of these compounds were observed by polarizing optical microscopy (POM) and differential scanning calorimetry (DSC). In this present investigation, we have synthesized two homologous series viz. 2-((3-phenyl allylidene) amino) phenyl 4-((4-n-alkoxy benzylidene) amino) benzoate (series-1) and 4-((2-((3-phenyl allylidene) amino) phenoxy) carbonyl) phenyl-4-n-alkoxy benzoate (series-2). Both the series are differing with respect to first linking group. In series-1, comp.C4–C18shows nematic as well as smectic phase while in series-2, comp.C10–C16shows smectic and nematic phase while comp.C4–C18shows only nematic phase. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
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27. X-ray diffraction and DSC study of 4-n-butyloxyphenyl 4′-hydroxybenzoate.
- Author
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Kuz'mina, L. G., Konstantinov, I. I., and Medvedev, A. G.
- Subjects
- *
X-ray diffraction , *ALKYL compounds , *PHASE transitions , *HYDROGEN bonding , *MESOPHASES - Abstract
4-n-Butyloxyphenyl 4′-hydroxybenzoate C4H9−O−C6H4−(O)OC−C6H4−OH have been investigated by single crystal X-ray structural analysis and DSC measurements. Crystal packing of the compounds and possible phase transitions are discussed. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
28. Synthesis and mesomorphic properties of 2,4-bis(4′-n-pentyloxybenzoyloxy)- benzylidine-4″- n-alkoxyaniline.
- Author
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Hamad, Wali M., Azeez, Hashim J., and Al-Dujaili, Ammar H.
- Subjects
- *
MESOPHASES , *NUCLEAR magnetic resonance , *MASS spectrometry , *DIFFERENTIAL scanning calorimetry , *MICROSCOPY - Abstract
The synthesis and mesomorphic properties of a new series of 2,4-bis(4′-npentyloxybenzoyloxy)- benzylidine-4″ -n-alkoxyaniline (DC5An) are reported. The molecular structure of compounds was confirmed by FTIR,1H-NMR,13C-NMR, mass spectroscopy and elemental analysis. The mesomorphic properties were studied by differential scanning calorimetry (DSC) and polarizing optical microscopy (POM) measurements. All compounds of the series exhibit nematic (N) and smectic C (SmC) phases. The first four homologues (DC5A1-DC5A4) display a N mesophase, whereas the highest homologues (DC5A5-DC5A10) exhibit an enantiotropic dimorphism N and SmC phases. The mesomorphic properties of the present series are compared and discussed with other structurally related series. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
29. Alkoxy/halostyryl benzoic acids: Synthesis, crystal structure, and study of mesomorphic and photophysical properties.
- Author
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Muhammad, Khushi, Rauf, M. Khawar, Tahir, M. Nawaz, and Hameed, Shahid
- Subjects
- *
ALKOXY compounds , *BENZOATES , *CHEMICAL synthesis , *BENZOATES analysis , *MESOPHASES , *MAGNETIC coupling - Abstract
Alkoxy/halostyrylbenzoic acids were synthesized and evaluated for their mesomorphic and photophysical properties. Thetransgeometry of the molecules was established by the presence of large coupling constants in1H-NMR spectra and confirmed further by X-ray diffraction (XRD) analysis of two of the compounds. The straight-chain acids were found fairly stable showing first sign of decomposition above 290°C. The enantiotropic mesophases could only be studied in acids with seven or more methylene groups in the alkoxy chain. Textures of nematic and smectic phases were exhibited by these acids under polarizing optical microscope. Photophysical behavior of the compounds in solution was also investigated. [ABSTRACT FROM PUBLISHER] more...
- Published
- 2017
- Full Text
- View/download PDF
30. NMR investigation of a thermotropic liquid crystal showing isotropic-isotropic'-(columnar)-cubic phase transitions.
- Author
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Cifelli, Mario, Domenici, Valentina, Gorecka, Ewa, Wojcik, Micham, and Dvinskikh, Sergey V.
- Subjects
- *
LIQUID crystals , *PHASE transitions , *NUCLEAR magnetic resonance , *MESOPHASES , *BIPHENYL compound derivatives , *ARRHENIUS equation - Abstract
In this work, we report a first detailed study of the mesophasic behaviour of the calamitic liquid crystal, a (4,4′-bis(4″-carboxybelzyloxy)biphenyl derivate, labelled 9/2 RS/RS, showing an isotropic-isotropic-(columnar)-cubic phase behaviour on cooling.1H NMR diffusometry allowed to distinguish between the two isotropic phases in terms of diffusion characterized by different Arrhenius activation energy, while13C NMR static measurements and2H NMR investigations were of help in understanding the orientational ordering properties of the metastable columnar phase and confirmed the isotropic state of the sample in the cubic phase. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
31. Morphological anisotropy of nano-dimensional arsenic trisulfide glass films and liquid crystal photoalignment.
- Author
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Sharpnack, Lewis, Kirzhner, Miri G., Agra-Kooijman, Deña M., Chaudhary, Ashok, Kumar, T. Arun, Klebanov, M., Sheremet, N., Reznikov, Yu, Abdulhalim, I., and Kumar, Satyendra
- Subjects
- *
LIQUID crystal states , *MESOMORPHIC transitions , *NANOSTRUCTURED materials , *LIQUID crystals , *MOLECULAR dynamics , *X-ray reflection , *MESOPHASES - Abstract
The results of high-resolution x-ray reflectivity study of nano-dimensionally thin arsenic trisulfide (As2S3) glass films reveal surface roughness anisotropy upon prolonged irradiation with polarized 436 nm blue light. The anisotropy correlates with the photoinduced anisotropy and LC photoalignment observed on these thin films. However, the As2S3film's thickness reduces drastically during the reflectivity experiments, and ambient oxygen and moisture penetrate the film and create a second altered thin layer on top of a thicker film of As2S3. The results confirm the viability of As2S3films for non-contact LC photoalignment material but suggests the need for further process optimization to reduce the films' degeneration to increase their effectiveness. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
32. Mesogens' orientation at cylindrical and spherical surfaces during transition from isotropic phase to nematic liquid crystal phase.
- Author
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Vasilchikova, E. N., Barabanova, N. N., Bogdanov, D. L., Belyaev, V. V., Bugrimov, A. L., and Dadivanyan, A. K.
- Subjects
- *
MESOMORPHIC transitions , *LIQUID crystals , *PHASE transitions , *MESOPHASES , *ISOTROPIC properties - Abstract
Structure of an oriented layer of mesogens on the interface at the isotropic phase (IP) – nematic liquid crystal (NLC) transition has been studied by polarization microscopy method. The thickness of the oriented layer was found to be equal to 50 ÷1000 µm, it decreases with a reduction of the surface curvature radius. Analytical expressions for the phase delay difference arising at passing of plane-polarized light through the mesogen layer oriented towards cylindrical and spherical surfaces have been obtained. The order parameter in mesogens at the IP-NLC transition was determined. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
33. Breaking planar liquid crystal anchoring to form controllable twist disclination loops.
- Author
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Angelo, Joseph, Culbreath, Christopher, and Yokoyama, Hiroshi
- Subjects
- *
LIQUID crystals , *MESOPHASES , *MESOMORPHIC transitions , *PHASE transitions , *MOLECULAR dynamics - Abstract
We have developed a new device called the dynamic cell, whereby the twist angle and cell thickness of a liquid crystal cell can be dynamically varied. For a twist angle larger than 90°, there occurs a breaking of anchoring at a certain threshold cell thickness. This structural transition converts the super-twisted state to a normal twisted state by flipping the surface director by 180°. A disclination loop separates the normal twisted region from the super-twisted region. By controlling the twist and thickness, we can stabilize this loop and calculate its line tension. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
34. Control of active nematics with passive liquid crystals.
- Author
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Guillamat, Pau, Ignés-Mullol, Jordi, and Sagués, Francesc
- Subjects
- *
NEMATIC liquid crystals , *MESOMORPHIC transitions , *MESOPHASES , *CRYSTAL chemical bonds , *NANOTECHNOLOGY , *BIOMATERIALS - Abstract
Motor-proteins are responsible for transport inside cells. Harnessing their activity is key towards developing new nano-technologies, or functional biomaterials. Cytoskeleton-like networks result from the self-assembly of subcellular autonomous units. Taming this biological activity bottom-up may thus require molecular level alterations compromising protein integrity. Taking a top-down perspective, here we prove that the seemingly chaotic flows of a tubulin-kinesin active gel can be forced to adopt well-defined spatial directions by tuning the anisotropic viscosity of a contacting Smectic-A liquid crystal. Different configurations of the active material are realized, when the thermotropic liquid crystal is either unforced or commanded by a magnetic field. The inherent instability of the extensile active fluid is thus spatially regularized, leading to organized flow patterns, endowed with characteristic length and time scales. Our finding paves the way for designing hybrid active/passive systems where ATP-driven dynamics can be externally conditioned. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
35. The electro-optical properties of doping toluene in inverted twisted nematic liquid crystals.
- Author
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Chiang, Yen-Te, Chou, Tsu-Ruey, Chen, Szu-Hua, and Chao, Chih-Yu
- Subjects
- *
LIQUID crystals , *MESOMORPHIC transitions , *CRYSTAL chemical bonds , *TOLUENE , *MESOPHASES - Abstract
The optimized electro-optical (EO) properties of inverse twisted nematic (ITN) liquid crystals (LCs) were demonstrated by utilizing liquid doping technique. ITN LC display is a driving system having 90° twisted structure on homeotropic polyimide with negative LCs. Toluene was chosen as dopants and doped into ITN LCs which successfully improved the driving voltage and response time of ITN LCs. The main reason of these EO properties enhancement is that toluene molecules penetrated between LC molecules and decreased the visco-elastic coefficient of LCs. The simplicity of liquid doping technique shows the potential to developments of a wide range of applications. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
36. Nanoparticle-induced vertical alignment liquid crystal cell with highly conductive PEDOT:PSS films as transparent electrodes.
- Author
-
Chen, Szu-Hua, Chou, Tsu-Ruey, Chiang, Yen-Te, and Chao, Chih-Yu
- Subjects
- *
LIQUID crystals , *LIQUID crystal films , *MESOMORPHIC transitions , *ELECTRODE potential , *MESOPHASES , *ELECTRODES - Abstract
In this work, high transmittance vertical alignment (VA) liquid crystal (LC) cells were accomplished by using highly conductive PEDOT:PSS films and polyhedral oligomeric silsesquioxane (POSS) nanoparticles. PEDOT:PSS films could be used as the transparent electrode and treated with rubbing process. Therefore, high contrast ratio VA cell without disclination lines could be achieved. Moreover, the electro-optical properties of LC cells fabricated by the rubbed PEDOT:PSS films and POSS were comparable to those constructed by indium tin oxide (ITO) and polyimide. Our work shows the potential of POSS-induced VA on rubbed PEDOT:PSS films for ITO-free and flexible LC displays. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
37. Enhanced columnar mesophase range through distortions in arene cores.
- Author
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Vollbrecht, Joachim, Wiebeler, Christian, Schumacher, Stefan, Bock, Harald, and Kitzerow, Heinz
- Subjects
- *
MESOPHASES , *LIQUID crystal states , *PHASES of matter , *LIQUID crystals , *DISCOTIC liquid crystals , *PERYLENE derivatives - Abstract
The influence of sterically hindered functional groups on liquid crystalline properties is studied for two series of perylene-3,4,9,10-tetracarboxylic tetraesters and diimides. The results indicate an enhanced mesophase range owing to the decrease of the melting temperature. The role of axial chirality is also studied by comparing the liquid crystalline properties of unilaterally and bilaterally extended perylene derivatives. In summary, both bulky substituents and distortion of the polycyclic aromatic core can lead to an enlarged temperature range of columnar mesophases. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
38. A practical lesson in polarization optics: Creating a 3D image using a liquid crystal cell.
- Author
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Polak, Robert D., Kumar, Akshar, and Schmidt, Matthew
- Subjects
- *
MESOMORPHIC transitions , *PHASE transitions , *LIQUID crystals , *POLARIZATION (Electrochemistry) , *MESOPHASES - Abstract
To demonstrate a practical application of polarization physics, a liquid crystal pi cell is used as a variable retarder to create different types of polarization. By varying the applied voltage to the cell, the polarization of the outgoing light can be controlled. Because of the rapid switching time of the pi cell, it is possible to alternate between orthogonal circular polarizations or orthogonal linear polarizations at a speed faster than can be reconciled by the human eye. Synchronizing images intended for different eyes with the polarization state of the cell, light of orthogonal polarization is incident upon a polarization maintaining screen. Through use of passive glasses that allow one state of polarization to pass while blocking the orthogonal state for each eye, the visual information will create a 3D image in the viewer's mind. The physics behind this can be described using bra-ket notation, and the experimental method is similar to that used in movie theatres and theme park attractions. It can be used as a practical demonstration of polarization physics and liquid crystal physics as well as an experiment in an upper-division laboratory course for physics majors. [ABSTRACT FROM AUTHOR] more...
- Published
- 2017
- Full Text
- View/download PDF
39. Mesomorphic and DFT studies of terminal ester containing salicylaldimines and their copper (II) complexes.
- Author
-
Singh, Hemant Kumar, Singh, Sachin Kumar, Kumar, Vijay, Kanth, Priyanka, Mishra, Kirtika, and Singh, Bachcha
- Subjects
- *
MESOPHASES , *DENSITY functional theory , *ESTERS , *IMINES , *COPPER ions , *METAL complexes , *DIFFERENTIAL scanning calorimetry , *CRYSTAL texture , *METALS - Abstract
In this article, we report synthesis and characterization of a novel homologous series of butyl 4-(4′-(alkoxy)-2-hydroxybenzylideneamino)benzoates, CnLH (n = 6, 8, 10, 12, 14, 16) and their copper(II) complexes. The mesomorphic properties of these compounds were investigated by differential scanning calorimetry (DSC), polarizing optical microscopy (POM) and powder X-ray diffraction (XRD) studies. The ligands and their copper(II) complexes exhibit wide range of enantiotropic smectic A mesophase as confirmed by their typical optical texture under polarizing microscope. Thermal stability of the compounds is determined by thermo gravimetric analyses. DFT calculations have been performed using GAUSSIAN-09 program at B3LYP level to obtain the stable electronic structure of the ligand and its copper(II) complex. [ABSTRACT FROM PUBLISHER] more...
- Published
- 2017
- Full Text
- View/download PDF
40. Effect of alkyl chain in the terminal ester group on mesomorphic properties of new rod like homologous series: Synthesis and characterization.
- Author
-
Sharma, Vinay S. and Patel, R. B.
- Subjects
- *
ALKYLSILANES , *ESTERS , *MESOPHASES , *STRUCTURAL rods , *CHEMICAL synthesis - Abstract
The mesomorphic properties of linear chalconyl ester homologous series can be tuned in a predictable fashion with tail groups (‒OC5H11) substituents on the terminal side and nitro group substitute at lateral position. Novel series consisted 13 members (C1to C8, C10, C12, C14, C16, C18). C1to C5homologues are nonliquid crystal, C6to C18homologues display smectic and nematic mesophase enantiotropically manner except C5homologue, which show only nematogenic mesophase. The texture of the nematic mesophase is of fan-shaped, Schlieren, and nematic droplets type. All these compounds were characterized by elemental analyses and spectroscopic techniques such as [FTIR] and1H Nuclear magnetic resonance [NMR] spectroscopy. The mesomorphic properties of these compounds were observed by optical polarized light microscopy (POM) and differential scanning calorimetry (DSC). [ABSTRACT FROM PUBLISHER] more...
- Published
- 2017
- Full Text
- View/download PDF
41. Synthesis and study of mesomorphic properties in rod-like chalconyl compounds.
- Author
-
Sharma, Vinay S. and Patel, R. B.
- Subjects
- *
MESOPHASES , *STRUCTURAL rods , *CURVES in engineering , *THERMOMETRY , *PHASE diagrams - Abstract
In order to investigate the influence of the central linking group and effect on flexibility on mesophase behavior of liquid crystal we have synthesized newly homologous series viz. 3-(4-Octyloxyphenyl)-1-(4′-n-alkoxy phenyl) prop-2-en-1-one (Series-l) consists of thirteen homologues (C1to C8, C10, C12, C14, C16, C18). Textures of a nematic phases are threaded or Schlieren type. The textures of smectic and nematic phase are directly judged from the heating and cooling condition. 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. A transition curve as depicted in a phase diagram behaves in normal manner. Structural and conformational characterization of these new compounds had achieved by1H NMR,13C NMR, IR, and elemental analysis. [ABSTRACT FROM PUBLISHER] more...
- Published
- 2017
- Full Text
- View/download PDF
42. Study the effects of terminal side chain and –nitro group on mesomorphic behaviour of cinnamate-chalconyl based liquid crystal.
- Author
-
Sharma, Vinay S. and Patel, R. B.
- Subjects
- *
LIQUID crystals , *CINNAMATES , *MESOPHASES , *FOURIER transform infrared spectroscopy , *DIFFERENTIAL scanning calorimetry - Abstract
The influence of the terminal side chain and lateral nitro on mesomorphism due to the flexibility and polarity of lateral group is investigated. A new homologues series is synthesized to accomplish this aim. The C1to C3homologue are nonmesomorphic, while the rest of the homologues exhibit enantiotropic nematic and smectic properties. The texture of the nematic mesophase is of threaded, Schlieren and droplets type. All these compounds were characterized by elemental analyses and spectroscopic techniques of FTIR and1H Nuclear magnetic resonance (NMR). The phase behaviour was studied by polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction techniques. [ABSTRACT FROM PUBLISHER] more...
- Published
- 2017
- Full Text
- View/download PDF
43. Dependence of mesomorphism on flexibility of lateral and terminal groups of chalconyl esters.
- Author
-
Patel, Priya K. and Shah, R. R.
- Subjects
- *
LIQUID crystals , *MOLECULAR structure , *VINYL ester resins , *TRANSITION temperature , *MESOPHASES - Abstract
A novel liquid crystalline homologous series of chalconyl vinyl esters with a lateral bromo substituent RO─C6H4─CH═CH─COO─C6H3─(Br)─CO-CH═CH─C6H4─C12H25(n)has been synthesized and studied with a view to understanding and establishing the relation between the molecular structure and liquid crystal (LC) behavior in terms of molecular flexibility of the lateral and terminal groups. The novel homologous series consists of thirteen (C1–C18) homologues, whose enantiotropic nematic and smectic mesomorphism commences from the C4, (C4–C18) and the C5, (C5–C18) homologue, respectively. The rest of the homologues (C1, C2, C3) are nonliquid crystals (NLC). Mesomorphism and transition temperatures were examined using an optical polarising microscope (POM) equipped with a heating stage. Textures of nematic phase are threaded or Schlieren and those of the Smectic-A or Smectic-C are focal conic. Analytical, thermal and spectral data supported molecular structures of the novel homologues. Thermal for smectic and nematic are 87.5°C and 101.1°C, respectively, whose, total mesophase length ranges from 17°C to 30°C at C14and C7homologue, respectively. The mesomorphic transition temperature ranges are between 70°C and 113°C. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
44. Synthesis, characterization and study of liquid crystal properties of new homologous chalcone series.
- Author
-
Jain, B. B. and Patel, R. B.
- Subjects
- *
LIQUID crystal synthesis , *CHALCONE , *PHENYL compounds , *MESOPHASES , *NEMATIC liquid crystals - Abstract
One new mesogenic homologous series of chalconyl derivative with two ring (3/-(4/- (decyloxy) phenyl-1-(4-(alkoxy) phenyl) prop-2-en-1-one) has been synthesized and characterized by a combination of elemental analysis and standard spectroscopic methods. In the series, the lower members (C4and C5) exhibit only enantiotropic nematic mesophase but middle and higher members exhibit enantiotropic nematic as well as smectic mesophase. The nematic mesophase commence from C4homologue and smectic mesophase (smectic-A type texture) commence from C6homologue as enantiotropic and persists up to the last member synthesized. 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. [ABSTRACT FROM PUBLISHER] more...
- Published
- 2016
- Full Text
- View/download PDF
45. The effect of molecular rigidity and flexibility on the mesomorphism of azoesters.
- Author
-
Jadeja, U. H. and Patel, R. B.
- Subjects
- *
MOLECULAR structure , *MESOPHASES , *ESTERS , *LIQUID crystals , *TRANSITION temperature - Abstract
An Azoester novel homologous series RO-C6H4-COO-C6H4-N˭N-C6H4-OC4H9(n)(para) of liquid crystalline (LC) materials are synthesized and studied with a view to understanding and establishing the effects of molecular structure on liquid crystal behavior with reference to lateral, terminal, or central group or groups on the basis of molecular rigidity and/or flexibility. The novel homologous series consists of thirteen (C1to C18) homologues. C1to C5homologues are nonmesogenic and the rest of the homologues are enantiotropically mesogenic. C8to C18homologues are smectogenic plus nematogenic and the remaining two C6and C7homologues are only nematogenic without exhibition of smectic property. Analytical, thermal and spectral data confirms the molecular structures. Textures and transition temperatures of homologues were determined by an optical polarizing microscope (POM) equipped with a heating stage. Textures of a nematic phases are threaded or Schlieren and that of a smectic phase are of the type of A or C. The average thermal stabilities for smectic and nematic are 111.3°C and 124.7°C, respectively. The smectic and nematicmesophase lengths from 10.0°C to 28.0°C and 7.0°C to 16.0°C, respectively. The transition temperatures are compared with known series. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
46. Mesomorphism dependence of a terminal or lateral alkoxy group.
- Author
-
Solanki, Ravindra and Patel, R. B.
- Subjects
- *
ALKOXY group , *MESOPHASES , *MOLECULAR structure , *CRYSTAL texture , *PHASE diagrams - Abstract
A novel homologous series of thermotropic mesomorphs has been synthesized and studied with a view to understanding and establishing the effect of molecular structure on mesomorphic properties with reference to rigidity and flexibility of the homologues series: RO-C6H4-CH˭CH-CO-C6H4-OC18H37(n). The novel homologous series comprises 13 novel homologues (C1to C18), from which 11 homologues are enantiotropically mesogenic (C3to C18). Smectogenic mesophase commences from C7homologue, and nematogenic mesophase is exhibited by C3to C18homologues in enantiotropic manner. Thus, C7to C18homologues are enantiotropically smectogenic plus nematogenic. Textures of smectic phase are of the type A or C, and that of nematic phase are threaded or Schlieren as confirmed through an optical polarizing microscope equipped with a heating stage. Transition curve of a phase diagram behaved in a normal manner except N-I transition curve, which shows minor deviating trend (C12to C18) from expected normal behavior. An odd-even effect is exhibited by N-I and Sm-N transition curves. Analytical, spectral, and thermal data confirm the molecular structures of novel homologues. Thermal stabilities for smectic and nematic are 52.7°C and 66.6°C, respectively, whose total mesophase lengths range from 12.0°C to 28.0°C. Thus, novel series of chalcones is a low melting series whose mesogenic transition temperatures vary between 38.0 and 86.0°C. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
47. Dependence of thermotropic mesomorphism on molecular flexibility of changing tail group.
- Author
-
Solanki, Ravindra, Sharma, Vinay, and Patel, Roshan
- Subjects
- *
LIQUID crystal synthesis , *MESOPHASES , *ESTERS , *MOLECULAR structure , *TRANSITION temperature , *NEMATIC liquid crystals , *THERMAL stability - Abstract
A novel chalconyl ester homologous series of liquid crystals has been synthesized and studied with a view to understanding and establishing the effect of molecular structure on liquid crystalline properties. Novel series consisted of 13 members (C1–C18) of a series. C1–C4member of a series is nonliquid crystals and, the rest of the homolog members (C5–C18) are enantiotropically nematogenic with absence of smectogenic property. None of the homolog is monotropically mesomorphic. Transition and melting temperatures were determined by an optical microscope equipped with a heating stage. Textures of nematic phase are threaded or schlieren. Spectral and analytical data of selected members of a series confirms the molecular structures of homologues. Cr-N and N-I transition curves of a phase diagram behaved in normal manner with exhibition of odd-even effect of very short range as observed for N-I transition curve. Thermal stability for nematic is 122.0°C and the nematogenic mesophase ranges from 7.0°C to 38.0°C. Liquid crystal properties of a present series are compared with the structurally similar known homologous series. [ABSTRACT FROM PUBLISHER] more...
- Published
- 2016
- Full Text
- View/download PDF
48. The influence of the thioalkyl terminal group on the mesomorphic behavior of some 6-alkoxy-2-naphthoates derived from 1,3,4-oxadiazole.
- Author
-
Chothani, N. J., Akbari, V. K., Patel, P. S., and Patel, K. C.
- Subjects
- *
MESOPHASES , *OXADIAZOLES , *NAPHTHALENE synthesis , *ALKYL group , *MOIETIES (Chemistry) , *NAPHTHALENE derivatives , *ESTERIFICATION - Abstract
A new series of mesogenic compounds having a naphthalene moiety has been synthesized by esterification of 4-(5-(alkyllthio)-1,3,4-oxadiazol-2-yl)phenol and 6-alkoxy-2-naphthoic acid and their liquid crystalline properties have been studied. All the members of the series are enantiotropic and exhibit smectic as well as nematic mesophase. The plot of transition temperatures versus number of carbon atoms in the alkoxy chain exhibits no odd even effect and falling tendency for isotropic transition temperatures. High anisotropy, linearity confers rich mesomorphic properties on the system. [ABSTRACT FROM PUBLISHER] more...
- Published
- 2016
- Full Text
- View/download PDF
49. Syntheses and room mesomorphic properties of novel gallic trimer and tetramer based on acylhydrazone structures.
- Author
-
Guo, Hongyu, Fang, Xiaoting, Yang, Fafu, and Wu, Yamin
- Subjects
- *
MESOPHASES , *HYDRAZONES , *GALLIC acid , *TEMPERATURE effect , *X-ray diffraction - Abstract
Two novel gallic trimer7and tetramer8based on acylhydrazone structures were designed and synthesized in yields 76% and 81%, respectively. Their structures were confirmed by1H NMR, ESI-MS, and elemental analysis. Their mesomorphic properties were investigated by DSC, POM, and XRD analyses. The mesomorphic results suggested that they possessed good room-temperature columnar liquid crystalline property with wide range of mesomorphic temperature. The ranges of mesomorphic temperatures for compounds7and8were as wide as 115°C and 124°C, respectively. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
50. Mesomorphism dependence on central bridges and the efficiency order of the tail group.
- Author
-
Bhola, G. N. and Bhoya, U. C.
- Subjects
- *
MESOPHASES , *PHOSPHOLIPIDS , *MOLECULAR structure , *SMECTIC liquid crystals , *LIQUID crystalline solvents , *TRANSITION temperature - Abstract
A novel homologous series: RO-C6H4‒CH˭CH‒COO‒C6H4‒CH˭N-C6H3(CH3)2of ortho-meta Schiff's bases has been synthesized and studied with a view to understanding and establishing the effects of molecular structure on mesomorphic properties and to provide a source of novel liquid crystalline (LC) materials. The series consists of 13 homologues (C1to C8, C10, C12, C14, C16& C18). C1and C3homologues are nonmesomorphic, C2and C4monotropicnematic, C6and C7monotropicsmectic in addition to enantiotropicnematic, C5is only enantiotropicnematic, C8, C10, C12are enantiotropically smectogenic plus nematogenic and C14, C16, C18homologues are enantiotropically smectic only. Textures and transition temperatures were determined using an optical polarizing microscope equipped with a heating stage. Analytical and spectral data confirm the molecular structures. Average smectic and nematic thermal stabilities are 100.16°C and 110.83°C, respectively. Mesomorphic properties of present novel series are compared with structurally similar homologous series. [ABSTRACT FROM AUTHOR] more...
- Published
- 2016
- Full Text
- View/download PDF
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