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The solvent effects on C=O stretching vibrational frequency, ν(C=O), of ketoprofen (KETO) were studied experimentally using attenuated total reflection infrared spectroscopy (ATR-IR). The experimental ν(C=O) of KETO were correlated with empirical solvent parameters, including the Kirkwood–Bauer–Magat (KBM) equation, the acceptor numbers (ANs) of the solvents, the Swain equation, linear solvation energy relationships (LSERs), and the quadratic equation (QE). The solvent-induced ν(C=O) shifts of KETO displayed a better correlation with the LSER equation than with the KBM equation, ANs of the solvents, and the Swain equation. The linear effect of the solvent hydrogen-bond donor acidity (Aj) on ν(C=O) of KETO was found to be highly significant, whereas the hydrogen-bond acceptor basicity (Bj) and the interaction effect of Aj and Bj were not significant. It was also observed that the quadratic effects of Aj and Bj were slightly significant. Additionally, the linear effect of LSER parameters (π*, δ, α, and β) and the interaction effect of π*β on the ν(C=O) of KETO were highly significant.

Fe3O4-SiO2-NH2, Fe3O4-CTABSiO2-NH2 and Fe3O4-SiO2-CTABSiO2-NH2 magnetic adsorbents were successfully prepared and could be used effectively for the adsorption of Light Green from aqueous solutions. Unlike the first sample, mesoporous silica coatings were created using cetyltrimethylammoniumbromide micelles as molecular templates on superparamagnetic iron oxide in one sample, and on silica-coated iron oxide in the other sample to improve the adsorptive properties of the nanocomposites. The characterization by FT-IR, SEM/EDX, Zeta-potential, XRD, VSM, and N2-adsorption/desorption confirmed the production of mesoporous silica layer. Although coating processes with both silica and mesoporous silica layers led to a vaguely decrease in saturation magnetization of the Fe3O4-SiO2-CTABSiO2-NH2, the nanoparticles were protected with silica coatings for environment conditions and made more suitable for subsequent amino functionalization. The results determined from Batch adsorption experiments fitted to Langmuir isotherm model with maximum adsorption capacity (qmax) equal to 56.18, 196.08 and 227.27 mg g−1, for Fe3O4-SiO2-NH2, Fe3O4-CTABSiO2-NH2 and Fe3O4-SiO2-CTABSiO2-NH2, respectively, and it was seen from the kinetic results, the LG adsorption was identified by pseudo-second-order kinetics, revealing that LG adsorption process is homogeneous, monolayer and based on chemical interactions. According to the results, both silica and mesoporous silica coating strategy can play crucial role in improving the adsorptive properties of nanocomposites.

The characterization of the hydrogel was performed using Fourier‐transform infrared spectroscopy, X‐ray diffraction, and scanning electron microscopy. Purified Bacillus pumilus Y7‐derived alkaline protease was immobilized in Poly (vinylimidazole)/clay (PVI/SEP) hydrogel with 95% yield of immobilization. Immobilization decreased the pH optimum from 9 to 6 for free and immobilized enzyme, respectively. Temperature optimum 3°C decreased for immobilized enzyme. The K m, V m, and k cat of immobilized enzyme were 4.4, 1.7, and 7.5‐fold increased over its free counterpart. Immobilized protease retained about 65% residual activity for 16th reuse. The immobilized protease endured its 35% residual activity in the material after six cycle's batch applications. The results of thermodynamic analysis for casein hydrolysis showed that the ΔG≠ (activation free energy) and ΔG≠ E‐T (activation free energy of transition state formation) obtained for the immobilized enzyme decreased in comparison to those obtained for the free enzyme. On the other hand, the value of ΔG≠ ES (free energy of substrate binding) was observed to have increased. These results indicate an increase in the spontaneity of the biochemical reaction post immobilization. Enthalpy value of immobilized enzyme that was 2.2‐fold increased over the free enzyme indicated lower energy for the formation of the transition state, and increased ΔS≠ value implied that the immobilized form of the enzyme was more ordered than its free form.

Fe3O4@SiO2@NH2 nanocomposite was prepared for highly effective adsorption of two anionic dyes one of which is triarylmethane dye (light green, LG) and the other is azo dye (brilliant yellow, BY). T...

In the present study novel 4-(4-ethyl-phenyl)-3-(4-methyl-phenyl)-1,2,4-oxadiazol-5(4H)-one (compound (4)) and 4-(4-ethyl-phenyl)-3-(4-methyl-phenyl)-1,2,4-oxadiazole-5(4H)-thione (compound (5)) were synthesized. These oxadiazole ring derivatives were characterized by IR, 1H NMR, 13C NMR and HRMS analyses. The solvent effects on C O, C N and C S stretching vibrational frequencies (ν(C O), ν(C N) and ν(C S)) of synthesized compounds were investigated experimentally using attenuated total reflection (ATR) infrared spectroscopy and compared with the theoretical results assigned using the potential energy distribution (PED) contributions. Furthermore, the ν(C O), ν(C N) and ν(C S) of compound (4) and compound (5) were correlated with empirical solvent parameters such as the solvent acceptor numbers, the Swain equation, the Kirkwood-Bauer-Magat equation, and the linear solvation energy relationships. Apart from the linear effects investigated in similar studies, solvent-induced vibrational shifts were investigated using the quadratic equation. The prediction capabilities of empirical solvent parameters were statistically compared. It was found that the linear solvation energy relationships show better correlation than the other empirical solvent parameters. Additionally, the quadratic equation provided more accurate predictions for the vibrational frequency locations than the Swain and the linear solvation energy relationships equations.

Ketoprofen is one of the propionic acid class of nonsteroidal anti-inflammatory drugs (NSAIDs). In the present study, the effects of three different solvents (DMSO, benzene and methanol) and gas phase on the geometrical, thermodynamic parameters and infrared spectra analyses of the ketoprofen have been investigated using the DFT/B3LYP with 6–31 G basis set. The recorded FT-IR spectra of ketoprofen are in agreement with the theoretical results. Also, the thermodynamic properties for different temperatures have been investigated in gas phase. The intra- and inter-molecular interactions have been determined by using the Hirshfeld surface and Reduced Density Gradient (RDG) analyses. Molecular docking studies have been performed to determine ketoprofen binding to human serum albumin (HSA).

This paper reports synthesis of the poly(ethylene glycol dimethacrylate-n-vinyl imidazole) ([poly(EGDMA-VIM)]) microspheres by suspension polymerization for the removal of phenol from an aqueous solution. The synthesized [poly(EGDMA-VIM)] microspheres were characterized by various analysis techniques. The [poly(EGDMA-VIM)] microspheres possessed a high specific surface area (304.4 m2 g(-1)). It was found that the pseudo-second-order kinetic and Freundlich isotherm models could well define the phenol adsorption process. The maximum capacity of the [poly(EGDMA- VIM)] microspheres was calculated to be 34.7441 mg g(-1) at 298 K and natural pH from Langmuir isotherm. The adsorption thermodynamics revealed that the adsorption of phenol was an exothermic and spontaneous process. The [poly(EGDMA-VIM)] microspheres were easily regenerated by using a 0.01 M NaOH solution, and were repeatedly used for at least 5 cycles without losing the adsorption capacity. The experimental results suggest that the [poly(EGDMA-VIM)] microspheres can be implemented as a promising adsorbent for phenol removal from wastewater.

We studied the adsorption of Brilliant Yellow (BY) from aqueous solutions onto sepiolite and determined the adsorption equilibrium isotherms. We applied pseudo-first-order and pseudo-second-order kinetic models; the adsorption of BY onto sepiolite was best described by the pseudo-second-order kinetic model. The experimental data obtained at different temperatures were analyzed using various isotherm models; the Koble–Corrigan isotherm model provided the best fits for the BY adsorption data at all temperatures. The thermodynamic parameters of the BY adsorption onto sepiolite indicated that the adsorption process is spontaneous and exothermic in nature.

For removal of Cu(II) ions from aqueous solution, a novel composite was prepared from 1-vinyl imidazole and sepiolite by the technique of in-situ polymerization. Adsorption of Cu(II) ions from aqueous solution onto Sepiolite-Poly(vinylimidazole) composite has been studied at 277, 298, 318, and 338 K and the experimental data were analyzed using fourteen isotherm models. The determination coefficients (R2) were determined for each isotherm analysis. The determination coefficients demonstrated that in general the accuracy of models to fit experimental data improves with the number of parameters. The Langmuir model provided the best fit to the experimental data among the two-parameter isotherms. The Toth model provided the best fit to the data among the three-parameter models. Adsorption isotherm modeling shows that the interaction of Cu(II) with Sepiolite-Poly(vinylimidazole) composite surface is localized to monolayer sorption and adsorption is an endothermic process. Additionally, adsorption experiments showed that Sepiolite-Poly(vinylimidazole) composite can be used as an effective adsorbent for the removal of Cu(II) ions from aqueous solution.

Solvent-induced frequency shifts in the infrared spectra of isophorone (IP), 4-oxo-isophorone (OIP), and 2,6,6-trimethyl-4,4-(ethylenedioxy)cyclohex-2-en-1-one (TEDCH) have been studied in 20 different organic solvents. The carbonyl stretching vibration frequencies of IP, OIP, and TEDCH were correlated with solvent properties, including the solvent acceptor number (AN) and the linear solvation energy relationships (LSER). The correlation results indicated that the LSER are better for describing the solute-solvent interactions than the solvent AN.

The dye sorption of Basic Yellow 28 (BY 28) in an adsorption process was optimized by varying three independent factors (initial pH, temperature, and ionic strength) using a central composite design, which is an experimental design that is useful in response surface methodology. The quantitative relationship was measured between the amount of the adsorbed dye (q, mg g−1) and the economical adsorbent, sepiolite, and the effect of initial pH, temperature, and ionic strength on the adsorption process was evaluated using the quadratic model. The model adequacy was tested by the analysis of variance, and the model was shown to be highly significant. The model showed that each of the independent factors was significant at the 5% significance level, revealing that the dye adsorption in the aqueous solution was affected by all three factors that were studied. The predicted maximum amount of adsorbed dye (31.54 mg g−1) was found using a solution pH of 6, a temperature of 25°C, and an ionic strength of 0.00...

In this study an extreme pressure and anti-corrosion additive package for gear oils has been created. In this context three different organic molecules were synthesized. Methylene-bis (dibutyldithiocarbamate), Sulfured oleic acid and o,o-Dialkyldithio Phosphate. Mass spectrums and Elemental analyses were carried out for these three molecules. For each molecule 4-ball weld points (WP), 4-ball Wear Scar Diameter (WSD), Copper corrosion (CC) and salt spray tests (SS) were carried out. Antioxidant properties of synthesized molecules were determined. According to the test results eight different additive packages were prepared and WP, WSD, CC and SS tests were applied to each package to determine a suitable package content. The highest yield was obtained in the five and six additive package with 250, 300 kg weld point and 0.41, 0.53 mm scar diameter respectively. For all additive packages the extreme pressure and corrosion resistance properties of gear oil increase by increasing the percentage of Methylene-bis (dibutyldithiocarbamate). o,o-Dialkyldithio Phosphate showed the highest antioxidant activity and it has been obtained bets corrosion protection with Sulfured oleic acid.

The adsorption of poly(1-vinylimidazole) (PVI) on Na-bentonite from aqueous solutions was investigated as a function of some parameters such as pH, ionic strength, and temperature. The adsorption of PVI increased with increasing pH and decreasing ionic strength and temperature. The electrophoretic mobility of Na-bentonite dispersions was measured at different PVI concentrations and pH. The results have shown that Na-bentonite can be used for adsorption of PVI from aqueous solutions. The second-order kinetic equation best fit the experimental data.

The adsorption of poly(1-vinylimidazole) (PVI) onto sepiolite from aqueous solutions was investigated as a function of some parameters such as pH, ionic strength, and temperature. The adsorption of PVI was increased with increasing pH and with decreasing ionic strength and temperature. The Langmuir isotherm model fitted the isotherm data better than the Freundlich model. The electrophorotic mobility of sepiolite dispersions was measured at different PVI concentrations and pH. The thermodynamic parameters Gibbs free energy, enthalpy, and entropy were evaluated. The dimensionless separation factor (R-L.) revealed that sepiolite can be used for adsorption of PVI from aqueous solutions. The second-order kinetics equation best fitted the experimental data. Dielectric properties of sepiolite coated with PVI have been also investigated. The sample with adsorbed PVI at 25 degrees C has the maximum the AC conductivity and the charge carriers can move easily in comparison with other samples. The real permittivities of the PVI-adsorbed samples are quite high in comparison with those of the pure polymer as a result of interface interactions. Kocaeli Üniversitesi -2007/071 Balıkesir Üniversitesi Uygulamalı Bilimler Araştırma Merkezi (BURCAS)

The synthesis of single wall nanotubes (SWNT)/poly(vinyl)triazole (PVTri) composites by in situ emulsion polymerization method and its chemical and physical properties were investigated throughout this work. The surface modification of the SWNT by nitric acid treatment and air oxidation has improved the dispersion of the SWNT in the PVTri matrix. The SWNT/PVTri composite is obtained by covalent bonding of the carboxyl terminated SWNTs to PVTri. The effect of covalent bond formation between PVTri and SWNT on the thermal and electrical properties of the composite is also studied. The spectroscopic, thermal, and microscopic analysis has confirmed the structure, homogeneity, and the morphology of surface functionalized SWNT and SWNT/PVTri composites. SWNT/PVTri composites showed enhanced chemical stability in many common solvents and high electrical conductivity.

The adsorption of poly(vinylimidazole) (PVI) onto Na–Bentonite from aqueous solutions has been investigated as a function of temperature. According to the experimental results, the adsorption of PVI decreases with temperature from 25 to 55°C. The study of temperature effect has been quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy changes. The electrical and dielectrical properties of PVI–Na–Bentonite composite have been investigated. The current-voltage studies show that conductivity was increased at T = 25°C. The dc conductivity was calculated at T = 25°C. The samples show typical dielectric behavior from capacitive measurements. Depending on maximum interactions at 25°C, ac conductivity and loss factors are also in high values. Especially, at frequencies over 1.5 kHz, it was seen completely clay behavior. Variation of tangent loss factor-frequency shows decreasing of polarization density in structure in high frequency. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Alkan, Mahir (Balikesir Author), Batch adsorption experiments were carried out in order to evaluate the maximum adsorption conditions of the anionic dye Brilliant Yellow (BY) from aqueous solutions on sepiolite using a 2(3) full factorial design The three factors were temperature the initial pH of the solution and the ionic strength of the dispersion The optimization of the factors to obtain maximum adsorption was carried out by incorporating effect plots normal probability plots interaction plots analysis of variance (ANOVA) Pareto charts surface plots and contour plots The statistical design experiments designed to reduce the total number of experiments required indicated that within the selected conditions all the parameters influenced at a significance level of 5% In addition some of the possible interactions between these parameters also influenced the adsorption process especially those that were of first order A regression model was suggested and fitted the experimental data very well.

Magnetic vinylphenyl boronic acid microparticles, poly(ethylene glycol dimethacrylate(EG)-vinylphenyl boronic acid(VPBA)) [m-poly(EG-VPBA)], produced by suspension polymerization and characterized, was found to be an efficient solid polymer for Cr(VI) adsorption. The m-poly(EG-VPBA) microparticles were prepared by copolymerizing of ethylene glycol dimethylacrylate (EG) with 4-vinyl phenyl boronic acid (VPBA). The m-poly(EG-VPBA) microparticles were characterized by N-2 adsorption/desorption isotherms, electron spin resonance (ESR), X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), thermal gravimetric analysis (TGA), elemental analysis, scanning electron microscope (SEM) and swelling studies. The m-poly(EG-VPBA) microparticles were used at adsorbent/Cr(VI) ion ratios. The influence of pH, Cr(VI) initial concentration, temperature of the removal process was investigated. The maximum removal of Cr(VI) was observed at pH 2. Langmuir isotherm and Dubinin-Radushkvich isotherm were found to better fit the experiment data rather than Fruendlich isotherm. The kinetics of the adsorption process of Cr(VI) on the m-poly(EG-VPBA) microparticles were investigated using the pseudo first-order, pseudo-second-order, Ritch-second-order and intraparticle diffusion models, results showed that the pseudo-second order equation model provided the best correlation with the experimental results. The thermodynamic parameters (free energy change, Delta G(0) enthalpy change, Delta H-0; and entropy change, Delta S-0) for the adsorption have been evaluated.

The refractive index ( n ) and thermal coefficient of the refractive index ( d n / d t ) are measured at four wavelengths for the diethylamine and triethylamine. The measurements are carried out using the Bellingham+Stanley model 60/ED high-accuracy Abbe refractometer. The optical permittivity ( e ) and its variation with temperature are calculated. Applying the Cauchy equation, the following refractive properties are obtained: the optical dispersion d n / d λ , the dielectric dispersion d e / d λ , the variation of - d n / d T , d e / d T , as a function of wavelength ( λ ), and Cauchy's constants against temperature. Additionally, molar refractivity versus temperature and wavelength are determined.

Adsorption, electrokinetic properties and the interactions between polymer and clay minerals have recently received much attention, owing to the physicochemical properties of these materials. In this study, surface properties of poly(vinylimidazole)-adsorbed expanded perlite such as adsorption, adsorption kinetics and electrokinetic properties have been investigated as a function of temperature, ionic strength and pH. The zeta potential measurements have been performed to determine the isoelectric point (iep) and potential determining ions (pdi). Although pH strongly altered the zeta potential of expanded perlite sample, expanded perlite does not yield any isoelectric point in the pH ranges of 2–11, poly(vinylimidazole) (PVI) changes the interface charge from negative to positive for expanded perlite when adsorbed on its surface. Adsorbed amounts ( q e ) showed a great dependence on pH. The adsorption of PVI increases with increasing pH, ionic strength and temperature. The pH values where the maximum adsorbed mass occurred might be considered as the conditions where electrostatic attraction is the most favourable. Experimental adsorption data were investigated using Langmuir and Freundlich isotherm models and found that Langmuir isotherm model gave the best representation of the adsorption equilibrium. In order to investigate the mechanism of adsorption and potential rate controlling step, pseudo-first- and second-order kinetic equations, and intraparticle diffusion model have been used to test the experimental data. The rate constants and the related correlation coefficients were determined in order to assess which model provides the best-fit predicted data with experimental results. Pseudo-first-order kinetic equation provided the best fit to experimental data.

The adsorption of PAM onto sepiolite from aqueous solutions has been investigated systematically as a function of some parameters such as calcination temperature of sepiolite, pH, ionic strength and temperature. The adsorption of cationic polyacrylamide (PAM) increases with pH from 5.50 to 11.00, temperature from 25 to 55 degrees C and ionic strength from 0 to 0.1molL(-1). The sepiolite sample calcined at 200 degrees C has a higher adsorption capacity than the other calcined samples. Adsorption isotherms of PAM onto sepiolite have been determined and correlated with common isotherm equations such as Langmuir and Freundlich isotherm models. The Langmuir isotherm model appeared to fit the isotherm data better than the Freundlich isotherm model. The physical properties of this adsorbent are consistent with the parameters obtained from the isotherm equations. The zeta potentials of sepiolite suspensions have been measured in aqueous solutions of NaCl and different PAM concentrations and pH. From the experimental results: (i) pH strongly alters the zeta potential of sepiolite, (ii) sepiolite has an isoelectric point at about pH 6.6 in water and about pH 8 in 250mgL(-1) PAM concentration, (iii) PAM changes the interface charge from negative to positive for sepiolite. Effect of temperature on adsorption has been quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy. The dimensionless separation factor (R(L)) has shown that sepiolite can be used for adsorption of PAM from aqueous solutions.

The adsorption of the cationic polymer, polyacrylamide (PAM), onto kaolinite was investigated. Polyacrylamides are among the most commonly used polymers in industry and adsorption of PAM onto kaolinite from aqueous solutions have been investigated systematically as a function of some parameters such as calcination temperature of kaolinite, pH, ionic strength and temperature. According to the experimental results, the adsorption of PAM increases with pH from 5.50 to 10.50; temperature from 25 to 55 °C and ionic strength from 0 to 0.1 mol L−1. The kaolinite sample calcined at 600 °C has a higher adsorption capacity than the other calcined samples. Adsorption isotherms of PAM onto kaolinite have been determined and correlated with common isotherm equations such as Langmuir and Freundlich isotherm models. The Langmuir isotherm model appeared to fit the isotherm data better than the Freundlich isotherm model. The physical properties of this adsorbent are consistent with the parameters obtained from the isotherm equations. Furthermore, the zeta potentials of kaolinite suspensions have been measured in aqueous solutions of NaCl and different PAM concentrations and pH. From the experimental results, (i) pH strongly alters the zeta potential of kaolinite, (ii) kaolinite has an isoelectric point at about pH 2.35 in water and about pH 8 in 200 mg L−1 PAM concentration and (iii) PAM changes the interface charge from negative to positive for kaolinite. The study of temperature effect has been quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy and entropy. The dimensionless separation factor (RL) has shown that kaolinite can be used for adsorption of PAM from aqueous solutions.

In this study, the UV absorbance of oxalic acid that change with temperature and concentration in the dissociation media was investigated. For every solution system, the relationships between absorbance, A, and concentration, c, were obtained at different temperatures. Molar extinction constants of the solutions were calculated by using the Lambert-Beer law. The results indicated the invalidity of Lambert-Beer's law at high concentrations. The temperature dependence of the molar extinction constant of each solution was determined.

Infrared spectroscopy studies of 1,3-indanedione (ID) in 16 different pure organic solvents were undertaken to investigate the solvent–solute interactions and to correlate solvent properties, such as the Kirkwood–Bauer–Magat (KBM) equation, the solvent acceptor number (AN) and the linear solvation energy relationships (LSER), using the infrared band shift. The correlations were performed both symmetric and asymmetric band stretching. Poor correlation between dielectric constants and the frequencies in both symmetric and asymmetric C O stretching showed that the KBM relationship was unsuitable for the molecule studied in this work. These frequencies exhibited a better correlation with the LSER than the solvent AN. The asymmetric C O stretching was found in better correlation than symmetric.

A sensitive and selective solid phase spectrophotometric method for the determination of trace amounts of inorganic mercury is described. Hg2+ was sorbed on a silica gel-packed column as an Hg2+–N,N′-bis(2-mercaptophenyl)ethanediamide (H2L) complex. The Hg2+ complex was eluted from the column using 7 mL of acetone. Various parameters including pH, column flow rate, and ligand concentration were optimized. The complex was found to obey Beer’s law from 2.3 to 73.7 µg mL−1 within the optimum range when the preconcentration factor was two. The effective molar absorption coefficient at 523 nm was 1.17×103 L mol−1 cm−1 at 523 nm. The concentration limits in Beer’s law dropped from 0.09 to 2.95 µg mL−1 within the optimum range when the preconcentration factor was 50. The relative standard deviation at a concentration level of 5 µg mL−1 Hg2+ (9 repetitive determinations) was 1.6%. The detection limits are 0.34 µg mL−1 and 0.015 µg mL−1 when the preconcentration factors are 2 and 50, respectively. The method has been used for routine determination of trace levels of Hg2+ in natural waters. The potential application of this method for the removal of Hg2+ from natural samples (sea water and lake water) spiked with 100 ng mL−1 of Hg2+ was studied. In order to validate the proposed method, LGC 6156 (harbour sediment – extractable metals) was analysed by this method. The results proved that excellent extraction of Hg2+ from both natural water samples was obtained by solid phase extraction using N,N′-bis(2-mercaptophenyl) ethanediamide.

Tekin, Nalan (Balikesir Author), The purpose of this report is to calculate the orientation polarizability of benzaldehyde, benzoic acid and oxalic acid in polar and nonpolar solvents. The calculations are based on the knowledge of permanent dipole moment of the solutions. Other important physical quantities such as refractive index, density, specific volume, dielectric constant, molar polarization and molar refractivity are also calculated. Dipole moments of the solutions are calculated by using measured dielectric constants of the solutions. The dielectric constant measurements were made at 100 kHz. Relationships between the polarizability and concentration, specific volume, dielectric constant and dipole moment of the solutions are suggested.

The chemically modified multiwalled carbon nanotubes (MWCNT)/poly(1-vinyl-1,2,4-triazole) (PVTri) composites were prepared via in situ emulsion polymerization. The morphological and structural properties of the surface-modified MWCNT and the synthesized MWCNT/PVTri composites were characterized by Fourier transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, and transmission electron microscopy. The electrical properties of the composite material were analyzed by conductivity measurements. The thermal analysis and the T-g value of the polymer were determined by differential scanning calorimetry technique. The obtained novel MWCNT/PVTri composites exhibited excellent solubility and possessed a slightly higher glass transition temperature than that of the pure polymer.

We present experimental evidence of combined effects of temperature, carrier concentration, electric field as well as disorder on charge transport in an organic field-effect transistor (OFET). Transfer characteristics of an OFET based on sexithiophene active layer were measured from 80 to 300 K. Thermally activated carrier mobility followed Arrhenius law with two activation energies. Carrier density variation led to finite extrapolated Meyer–Neldel (MN) temperature (780 K) at low fields. Negative electric field-dependent mobility was observed in available field range. MN temperature shifted towards higher temperature when the electric field increased, and did not retain its finite character above the field of 4 × 103 V cm−1.

The effects of 15 solvents on the C=O stretching vibrational frequency of flurbiprofen (FBF) were determined to investigate solvent–solute interactions. Solvent effects on the geometry and C=O stretching vibrational frequency, ν (C=O), of FBF were studied theoretically at the DFT/B3LYP and HF level in combination with the polarizable continuum model and experimentally using attenuated total reflection infrared spectroscopy (ATR-IR). The calculated C=O stretching frequencies in the liquid phase are in agreement with experimental values. Moreover, the wavenumbers of ν (C=O) of FBF in different solvents have been obtained and correlated with the Kirkwood–Bauer–Magat equation (KBM), the solvent acceptor numbers (ANs), and the linear solvation energy relationships (LSERs). The solvent-induced stretching vibrational frequency shifts displayed a better correlation with the LSERs than with the ANs and KBM.

Köçkar, Hakan (Balikesir Author), In this paper we report the electrical characteristics of the Schottky diodes formed by surface polymerization of the Poly(ethylene glycol dimethanylate-n-vinyl imidazole)/Single Walled Carbon Nanotubes on n-Si The Single Walled Carbon Nanotubes were synthesized by CVD method. The main electrical properties of the Poly(ethylene glycol dimethanylate-n-vinyl imidazole)/Single Walled Carbon Nanotubes/n-Si have been investigated through the barrier heights, the ideality factors and the impurity density distribution, by using current-voltage and reverse bias capacitance voltage characteristics. Electrical measurements were carried out at room temperature. Poly(ethylene glycol dimethacrylate-n-vinyl imidazole)/Single Walled Carbon Nanotubes/n-Si Schottky diode current-voltage characteristics display low reverse-bias leakage currents and average barrier heights of 0.61 +/- 0.02 eV and 0.72 +/- 0.02 eV obtained from both current-voltage and capacitance-voltage measurements at room temperature, respectively.

Single-walled carbon nanotube (SWCNT) polyvinylimidazole (PVI) composites have been prepared by in situ emulsion polymerization. Dispersion of raw SWCNTs in the PVI matrix was improved by surface modification of the SWCNTs using nitric acid treatment and air oxidation. The carbonyl-terminated SWCNTs were covalently bonded to PVI by in situ polymerization and the SWCNT/PVI composite was thus obtained. The morphological and structural characterizations of the surface-functionalized SWCNTs and SWCNT/PVI composites were carried out by Fourier transform infrared spectroscopy, X-ray diffraction, conductivity measurements, scanning, and transmission electron microscopy. Thermograms of the materials were determined by the differential scanning calorimetry technique. The characterization results indicate that PVI was covalently bonded to SWCNTs and a new material was then obtained. The functionalized SWCNTs showed homogenous dispersion in the composites, whereas purified SWCNT resulted in poor dispersion and nanotube agglomeration. SWCNT/PVI composites exhibited chemical stability enhancement in many common solvents. IV curves of the samples exhibit an ohmic character. Conductivity values for pure SWCNTs, pure PVI and SWCNT/PVI composite were measured to be 3.47, 2.11 X 10-9, and 2.3 X 10-3 S/m, respectively. Because of resonance, a large dielectric constant is obtained for SWCNT/PVI composite, which is not observed for ordinary materials. POLYM. COMPOS., 2012. (c) 2012 Society of Plastics Engineers

Graphical abstract Electric chatacterization of organic field effect transistors with PVT dielectric layer: Pentacene is used as active layer in p-channel device; Fullerene is the active layer in n-channel device. Channel length is 2mm, channel width is 0.06mm. Research highlights ► PVT shows low leakage current and high breakdown voltage. ► Both n-channel and p-channel OFET devices give low threshold voltage and are lack of hysteresis. ► Excellent film formation property of PVT allows for fabricating low voltage operation OFET devices. ► All solution processed polymer ambipolar OFET device is realized via layer by layer coating., Water soluble poly(1-vinyl-1,2,4-triazole) (PVT) as a novel dielectric layer for organic field effect transistor is studied. Dielectric spectroscopy characterization reveals it has low leakage current and rather high breakdown voltage. Both n-channel and p-channel organic field effect transistors are fabricated using pentacene and fullerene as active layers. Both devices show device performances with lack of hysteresis, very low threshold voltages and high on/off ratios. Excellent film formation property is utilized to make AlOx and thin PVT bilayer in order to decrease the operating voltage of the devices. All solution processed ambipolar device is fabricated with simple spin coating steps using poly(2-methoxy-5-(2-ethyl-hexyloxy)-1,4-phenylenevinylene) (MEH–PPV) end capped with polyhedral oligomeric silsesquioxanes (POSS) as active layer. Our investigations show that PVT can be a very promising dielectric for organic field effect transistors.

Alkan, Mahir (Balikesir Author), The adsorption of cationic polyacrylamide (C-PAM) onto expanded perlite (EP) from aqueous solutions was investigated as a function of some parameters such as pH, ionic strength, and temperature. The adsorption of C-PAM was increased with increasing pH and temperature and with decreasing ionic strength. The Langmuir isotherm model fitted the isotherm data better than the Freundlich model. The electrophorotic mobility of EP dispersions was measured in aqueous solutions of NaCl and at different C-PAM concentrations and pH. The thermodynamic parameters Gibbs free energy, enthalpy, and entropy were evaluated. The dimensionless separation factor (R-L) revealed that EP can be used for adsorption of C-PAM from aqueous solutions. The pseudo first-order kinetics equation best fitted the experimental data.

The adsorption of polyvinylimidazole (PVI) onto kaolinite from aqueous solutions has been investigated systematically as a function of parameters such as calcination temperature of kaolinite, pH, ionic strength, and temperature. According to the experimental results, the adsorption of PVI increases with pH from 8.50 to 11.50, temperature from 25 to 55 degrees C, and ionic strength from 0 to 0.1 mol L(-1). The kaolinite sample calcined at 600 degrees C has a maximum adsorption capacity. Adsorption isotherms of PVI onto kaolinite have been determined and correlated with common isotherm equations such as Langmuir and Freundlich isotherm models. The Langmuir isotherm model appeared to fit the isotherm data better than the Freundlich isotherm model. The physical properties of this adsorbent are consistent with the parameters obtained from the isotherm equations. Furthermore, the zeta potentials of kaolinite suspensions have been measured in aqueous solutions of different PVI concentrations and pH. From the experimental results, (i) pH strongly alters the zeta potential of kaolinite; (ii) kaolinite has an isoelectric point at about pH 2.35 in water and about pH 8.75 in 249.9 ppm PVI concentration; (iii) PVI changes the interface charge from negative to positive for kaolinite. The study of temperature effect has been quantified by calculating various thermodynamic parameters such as Gibbs free energy, enthalpy, and entropy changes. The dimensionless separation factor (RL) has shown that kaolinite can be used for adsorption of PVI from aqueous solutions.

Tekin, Nalan (Balikesir Author), Infrared spectroscopy studies of trimethyl phosphate (TMP) in 17 different pure organic solvents were undertaken to investigate the solvent-solute interactions and to correlate solvent properties such as the Kirkwood-Bauer-Magat (KBM) equation, the solvent acceptor number (AN) and the linear solvation energy relationships (LSER), respectively, with the infrared band shift. Poor correlation between dielectric constants and the frequencies showed that the KBM relationship was unsuitable for the investigated molecules. These frequencies exhibited a better correlation with the LSER than the solvent AN.

All solution processed ambipolar bulk heterojunction organic field effect transistors were fabricated using Au and Al as hole and electron injection contacts to study both types of charge carrier mobilities in a single device. Poly(3-hexylthiophene) (P3HT) and [6,6]-phenyl C61 butyric acid methyl ester (PCBM) were mixed with different ratios. Well balanced electron and hole mobilities were obtained at 1:0.3 ratio. Organic solar cells with the same ratio yielded draft enhancement in device performance parameters, indicating optimized carrier transport in the bulk of solar cell devices.