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Öğe A study of the thermodynamical interactions with solvents and surface characterisation of liquid crystalline 5-((S)-3,7-dimethyloctyloxy)-2-[[[4-(dodecyloxy)phenyl]imino]-methyl]phenol by inverse gas chromatography(Elsevier, 2016) Ocak, Hale; Mutlu Yaniç, Serap; Çakar, Fatih; Bilgin Eran, Belkis; Güzeller, Dilek; Karaman, Ferdane; Cankurtaran, ÖzlemAn inverse gas chromatography (IGC) study of thermodynamic interactions of a new chiral calamitic liquid crystalline 54(S)-3,7-Dimethyloctyloxy)-2-[[[4-(dodecyloxy)phenyl]imino]methyl]phenol (DODPIMP) with some solvents was presented. The retention diagrams of the solvents on the DODPIMP were plotted by specific retention volumes, V-g(0) at temperatures between 373.2 and 393.2 K. The Flory-Huggins interaction parameter, chi(infinity)(12), the weight fraction activity coefficient, Omega(infinity)(1) and selectivity coefficients, alpha, of the structural isomers were determined for the DODPIMP liquid crystal. To characterize the surface properties of, retention diagrams of several non-polar and polar solvents on the DODPIMP were plotted by net retention volumes, V-N in the temperature rangefrom 303.2 to 318.2 K. The dispersive surface energy, the thermodynamic adsorption parameters and the acid-base constants of the compound in the crystalline phase were determined. The results indicated a basic character for the surface of DODPIMP at the studied conditions.Öğe Investigation of thermodynamic and surface characterisation of 4-[4-(2-ethylhexyloxy)benzoyloxy] benzoic acid thermotropic liquid crystal by inverse gas chromatography(Taylor & Francis Ltd, 2014) Çakar, Fatih; Ocak, Hale; Öztürk, Emine; Mutlu Yanıç, Serap; Kaya, Dila; San, Nevim; Cankurtaran, ÖzlemThe inverse gas chromatography method was used to obtain thermodynamic and surface properties of the thermotropic liquid crystalline material, 4-[4-(2-ethylhexyloxy) benzoyloxy]benzoic acid (EBBA). The retention diagrams of undecane, dodecane, tridecane, ethyl acetate, n-butyl acetate, iso-butyl acetate, toluene, ethylbenzene, iso-propylbenzene, n-propylbenzene and chlorobenzene on EBBA were plotted at temperatures between 443.2 and 468.2 K. The specific retention volume, V-g(0), Flory-Huggins interaction parameter, chi(infinity)(12), equation-of-state interaction parameter,. chi(*)(12), and effective exchange energy parameter, X-eff, were determined. The dispersive component of the surface free energy, gamma(D)(S), of the studied adsorbent surface was estimated using retention times of different nonpolar organic solvents in the infinite dilution region. The specific free energy of adsorption, Delta G(A)(S), the enthalpy of adsorption, Delta H-A(S), and the entropy of adsorption, Delta S-A(S), of solvents on liquid crystal were determined. The values of Delta H-A(S) were correlated with the donor and the acceptor numbers of the probes to quantify the acidic K-A and the basic K-D parameters of the liquid crystal surface. The values obtained for K-A and K-D parameters indicated an acidic character for the surface of EBBA.Öğe Morphology and preparation of polymer dispersed liquid crystals by solvent-induced phase separation method(National Institute of Optoelectronics, 2017) Mutlu Yaniç, Serap; Ocak, Hale; Çakar, Fatih; Bilgin Eran, Belkıs; Güzeller, Dilek; Cankurtaran, ÖzlemA new salicylaldimine based chiral calamitic liquid crystal 5-((S)-3,7-dimethyloctyloxy)-2-[[[ 4-(octyloxy) phenyl] imino] methyl] phenol (DOPIMP) has been synthesized and characterized by spectroscopic methods (1H-NMR and C-13-NMR). Polymer dispersed liquid crystal (PDLC) composite films were prepared from poly(methyl methacrylate) (PMMA) and DOPIMP by solvent-induced phase separation (SIPS) method. Polymer and LC composite films were controlled with ratio 20: 80(wt.% LC) and 30: 70(wt.% LC). The mesomorphic behavior of DOPIMP liquid crystal has been investigated by differential scanning calorimetry (DSC) and optical polarizing microscopy (PM). The mesophase of PDLC composite films were characterized by PM and the morphology of the PDLC composite films was studied using a scanning electron microscope (SEM).Öğe Synthesis, preparation, and characterization of liquid crystal/organo-montmorillonite nanocomposites(Taylor & Francis Ltd, 2015) Mutlu Yaniç, Serap; Güzeller, Dilek; Ocak, Hale; Çakar, Fatih; Erol, İsmail; Cankurtaran, Özlem; Bilgin Eran, BelkısA new chiral calamitic liquid crystal 4 '-((S)-3,7-dimethyloctyloxy)phenyl 4-(10-undecen-1-yloxy)benzoate (DOPUB) has been synthesized and characterized by spectroscopic methods (H-1-NMR and C-13-NMR). The focus is on the preparation of the nanocomposites of new chiral calamitic liquid crystal DOPUB/Organo-montmorillonite clay (OMMT) by solution intercalation method addition with OMMT contents 2.5, 5, and 7.5 wt% and determination of the morphology, thermal behavior, and crystalline properties of liquid crystal DOPUB/OMMT. Montmorillonite (MMT) modified by cationic surfactant cetyltrimethylammonium bromide (CTAB) for increasing the interaction of clay with DOPUB liquid crystal. The characterization of clay minerals and nanocomposites was investigated by X-ray diffraction. The mesomorphic behavior of liquid crystal (DOPUB) and the nanocomposites was investigated by differential scanning calorimetry (DSC) and optical polarizing microscopy (PM).Öğe Thermodynamic Characterization of Surface and Solubility of 5-((S)-3,7-Dimethyloctyloxy)-2-[[[4-(octyloxy)phenyl]imino]methyl]phenol Liquid Crystal with Some Solvents(American Chemical Society, 2019) Yaniç, Serap Mutlu; Çakar, Fatih; Ocak, Hale; Karaman, Ferdane; Cankurtaran, Özlem; Bilgin Eran, BelkızThe inverse gas chromatography method was used to obtain dispersive surface energy, surface acidity or basicity constants, mole fraction activity coefficients of the solvents at infinite dilution for a new salicylaldimine based chiral calamitic liquid crystal 5-((S)-3,7dimethyloctyloxy)-2-[[[4-(octyloxy)phenyl]imino]methyl]phenol (DOPIMP). The dispersive surface energy of DOPIMP was estimated as 41.1 mJ/m(2) at 30 degrees C and decreased with temperature. The specific free energy, enthalpy, and entropy of adsorption of the selected polar solvents on the liquid crystal were determined. The values of adsorption enthalpy were correlated with both donor and acceptor numbers of the solvents to quantify acidic KA and basic KD parameters of the liquid crystal surface. The results indicated that the surface of DOPIMP is basic. The retention diagrams of n-hexane, n-heptane, n-octane, n-nonane, n-decane, undecane, ethyl acetate, n-butyl acetate, iso-butyl acetate, toluene, ethylbenzene, n-propylbenzene, and chlorobenzene on the DOPIMP were plotted as straight lines using the net retention volumes at temperatures between 368.2 and 398.2 K. The values of activity coefficients indicated that DOPIMP was better soluble in long chain alkanes. Negatively signed partial molar Gibbs energies of mixing were obtained at infinite dilution of studied solvents.
