Browsing by Author "Tekin, Nalan"

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Adsorption and dielectric properties of poly(1-vinylimidazole) on sepiolite
(Elsevier, 2012-03) Tekin, Nalan; Kaya, A. Uğur; Esmer, Kadir; Kara, Ali; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Kimya Bölümü.; AAG-6271-2019; 7102824859
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.
Adsorption of light green and brilliant yellow anionic dyes using amino functionalized magnetic silica (Fe 3 O 4 @SiO 2 @NH 2) nanocomposite
(Taylor, 2019-01-01) Erdem, Beyhan; Avşar, Saliha Buşra; Erdem, Sezer; Tekin, Nalan; ERDEM, BEYHAN; Avşar, Saliha Buşra; ERDEM, SEZER; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü; AAI-1238-2021; AAI-1248-2021; CDX-3142-2022
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). The characterization results demonstrated that superparamagnetic Fe3O4 nanoparticles were covered with silica and functionalized with amino groups successfully without losing magnetic character. The effects of adsorbent dosage, contact time, pH, temperature, and dye molecular structure on the adsorption were investigated. Acidic pH was better for both LG and BY, on the other hand, alkaline pH was favorable to some extent for LG in comparison with BY due to the contribution of stacking effect in addition to electrostatic attraction. Kinetic data demonstrated that the driving force for adsorption process could be explained by pseudo-second order mechanism in both systems. The equilibrium data were more compatible with Langmuir isotherm than those of Freundlich isotherm and the maximum adsorption capacities of Fe3O4@SiO2@NH2 calculated from Langmuir isotherm model for LG and BY at 30 degrees C and natural pH of the solution were 40.2 and 35.5 mg g(-1). Thermodynamic calculations related to temperature dependence demonstrated that the adsorption process was spontaneous and exothermic.
Cationic surfactant templated synthesis of magnetic mesoporous nanocomposites for efficient removal of Light Green
(Korean Institute Chemical Engineers, 2021-06-22) Erdem, Beyhan; Erdem, Sezer; Tekin, Nalan; ERDEM, BEYHAN; ERDEM, SEZER; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü; AAI-1238-2021; AAI-1248-2021
Fe3O4-SiO2-NH2, Fe3O4-CTABSiO(2)-NH2 and Fe3O4-SiO2-CTABSiO(2)-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 N-2-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-CTABSiO(2)-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 (q(max)) equal to 56.18, 196.08 and 227.27 mg g(-1), for Fe3O4-SiO2-NH2, Fe3O4-CTABSiO(2)-NH2 and Fe3O4-SiO2-CTABSiO(2)-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.
Electrical properties of poly(ethylene glycol dimethacrylate-n-vinyl imidazole)/single walled carbon nanotubes/n-Si schottky diodes formed by surface polymerization of single walled carbon nanotubes
(Elsevier Science, 2012-01-01) Tekin, Nalan; Beyaz, Saadet; Koçkar, Hakan; Ahmetoğlu, Muhitdin; Kara, Ali; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; AAG-6271-2019; 16021109400; 7102824859
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.
In situ polymerization synthesis and characterization of single wall nanotubes/poly(vinyl)triazole nanocomposites
(Sage Publications, 2011-07) Beyaz, Saadet K.; Tekin, Nalan; Şimşek, Eyüp; Çakmak, Gülbeden; Güney, H. Yüksel; Lamari, Farida D.; Kara, Ali; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Anabilim Dalı.; AAG-6271-2019; 7102824859
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.
Investigation of dissociation properties of oxalic acid-solvent systems by UV-spectrophotometry
(Elsevier, 2005-11-15) Tekin, Nalan; Cebe, Mustafa; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; 6506210722
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.
Magnetic porous polymer microspheres: Synthesis, characterization and adsorption performance for the removal of phenol
(Taylor & Francis Inc, 2019-06-03) Özdemir, İnci; Tekin, Nalan; Kara, Ali; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; 0000-0003-2457-6314; AAG-6271-2019; 7102824859
The magnetic poly(ethylene glycol dimethacrylate-n-vinylimidazole) (Fe3O4@poly (EGDMA@VIM)) microspheres were prepared by suspension polymerization method using magnetite Fe3O4 nano-powder and the porosity, morphology, chemical composition and structure of the magnetic polymer microspheres were characterized. The specific surface area and swelling ratio of the Fe3O4@poly(EGDMA@VIM) microspheres were found to be 278.6m(2).g(-)1 and 48%, respectively. The Fe3O4@poly(EGDMA@VIM) microspheres were used as an adsorbent for phenol removal. The effects of the parameters such as adsorbent dosage, temperature, pH and initial concentration of phenol solutions on the adsorption were investigated. The experimental adsorption equilibrium data obtained were fitted with Langmuir, Freundlich and Dubinin-Radushkevich isotherms and the pseudo-first-order, pseudo-second-order and intra-particle diffusion kinetic models. The adsorption equilibrium data agreed well with the Freundlich isotherm and the pseudo-second-order kinetic model. The maximum capacity of the Fe3O4@poly(EGDMA@VIM) microspheres was calculated to be 33.83mg.g(-)1 at 298K and natural pH from Langmuir isotherm. The Fe3O4@poly(EGDMA@VIM) microspheres were found to be reusable for removal of phenol after desorption for several times. The result indicated that the Fe3O4@poly(EGDMA@VIM) microspheres are potential candidate for removal of phenol in wastewaters.
Magnetic vinylphenyl boronic acid microparticles for Cr(VI) adsorption: Kinetic, isotherm and thermodynamic studies
(Elsevier, 2015-04-09) Tekin, Nalan; Kara, Ali; Demirbel, Emel; Osman, Bilgen; Beşirli, Necati; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Anabilim Dalı.; ABF-4791-2020; AAG-6271-2019; 7102824859; 54681740300; 15221651200; 6507924888
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.
Physicochemical parameters of hg(ii) ions adsorption from aqueous solution by sepiolite/polyvinylimidazole)
(Elsevier Sci Ltd, 2016-06-01) Tekin, Nalan; Şafaklı, Akif; Kara, Ali; KARA, ALİ; Alan, Aysu; Bursa Uludağ Üniversitesi/Fen Edebiyat Fakültesi/ Kimya Bölümü.; 0000-0003-2457-6314; AAG-6271-2019
The sepiolite/Poly(vinylimidazole) (sepiolite/PVI) composite was prepared by in situ polymerization of vinyl imidazole (VIM) and sepiolite, which was not modified. Fourier Transform Infrared (FTIR) analysis, X-ray diffraction (XRD) spectra, Scanning Electron Microscopy (SEM) images and Differential Scanning Calorimetry (DSC) exhibited that sepiolite/PVI composite was successfully produced. The theoretical maximum adsorption capacity was calculated to be 345.3 mg g(-1) (concentration range of 100-1000 mg L-1) in Hg(II) solution at pH 6.5 at 298 K. The adsorption kinetics and isotherms were also investigated for the adsorption process. The adsorption isotherms data were well fitted to the Langmuir model for the adsorption of Hg(II) onto sepiolite/PVI. The thermodynamic parameters (Delta G', Delta H degrees, and Delta S degrees) were calculated which the composite could be considered as a spontaneous, endothermic and mainly physical adsorption process. The equilibrium parameter (R-L) indicated that sepiolite/PVI composite was useful for Hg(II) removal from aqueous solutions.
Polarizabilities and dipole moments of benzaldehyde, benzoic acid and oxalic acid in polar and nonpolar solvents
(Elsevier, 2004-05-10) Tekin, Nalan; Tarımcı, Çelik; Cebe, Mustafa; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; 6506210722
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.
Preparation, characterization, and antibacterial activity of organo-sepiolite/chitosan/silver bionanocomposites
(Taylor, 2019-05-04) Tekin, Nalan; Şafakli, Akif; Budak, Fatma; Kara, Ali; Bursa Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Fizik Bölümü.; 0000-0003-2457-6314; AAG-6271-2019; 7102824859
Bionanocomposites with different loadings of silver (Ag) were prepared via synthesis of Ag nanoparticles (AgNPs) using the wet chemical reduction method in the lamellar space layer of the organo-sepiolite/chitosan (O-SEP/CS). The prepared O-SEP/CS/Ag bionanocomposites were characterized using various analysis methods for their structure, morphology, and optical properties. The characteristic absorption bands from the UV-visible absorption spectrum confirmed the formation of AgNPs. The antibacterial activities of O-SEP/CS/Ag bionanocomposites were investigated against gram-positive and gram-negative bacteria using the disc diffusion method. The results suggest that O-SEP/CS/Ag bionanocomposites can be useful in wide range of bio-medical applications because of high antibacterial activity.
Preparation, Solubility, and Electrical Properties of Multiwalled Carbon Nanotubes/Poly(1-vinyl-1,2,4-triazole) Composites via in situ Functionalization
(Taylor & Francis Inc, 2014-05-13) Tekin, Nalan; Beyaz, Saadet Kayıran; Şimşek, Eyüp; Çakmak, Gülbeden; Güney, Hasan Yüksel; Lamari, F. D.; Kara, Ali; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Kimya Bölümü.; AAG-6271-2019; 7102824859
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.
Solvents effect on infrared spectra of trimethyl phosphate in organic solvents
(Elsevier, 2004-10-18) Tekin, Nalan; Cebe, Mustafa; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; 6506210722
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.
Surface properties of poly(vinylimidazole)- adsorbed expanded perlite
(Elsevier, 2006-07-28) Tekin, Nalan; Kadıncı, Emine; Demirbaş, Özkan; Alkan, M.; Doğan, Mehmet; Kara, Ali; Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Kimya Bölümü.; AAG-6271-2019; 7102824859
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.
Synthesis and characterization of 1-vinyl-1,2,4-triazole, m-poly(egdma-vta)-tio 2 polymer composite particles and the using of reactive orange 16 dye in adsorption and photocatalytic decolorization
(Springer, 2023-12-27) Tekin, Nalan; Demirel, Sibel; Mutlu, Gözde Koçak; Kara, Ali; KARA, ALİ; Bursa Uludağ Üniversitesi/Fen Edebiyat Fakültesi/Kimya Anabilim Dalı.; 0000-0003-2457-6314; F-5569-2018
Adsorption and photocatalytic decolorization methods were used to remove Reactive Orange 16 dye from textile wastewater by using ethyleneglycoldimethacrylate and 1-vinyl-1,2,4-triazole, m-poly(EGDMA-VTA)-TiO2 polymer composite particles with magnetic synthesized by suspension polymerization. The characterization of the synthesized m-poly(EGDMA-VTA)-TiO2 particules were carried out by using XRD, FTIR, SEM-EDS-elemental mapping, ESR, and BET analyses. Both adsorption and photocatalytic decolorization processes of RO16 dye were applied to the polymer particles. The effects of solution pH, amount of adsorbent, initial dye concentration, temperature, and time on the adsorption capacity were investigated. The removal of R016 dye reached a maximum at pH 3. Dye substance removal decreased due to increasing temperature and adsorbent amount. As a result of experimental studies, the adsorption of RO16 dye was explained by the Langmuir isotherm, while its kinetics was stated by a pseudo-second-order mechanism. Additionally, thermodynamic functions (Delta H-o, Delta G(o), and Delta S-o) have been determined. At the end of adsorption, the decolorization kinetics were elucidated by examining the adsorbent amount, time, and dye concentration parameters for the photocatalytic decolorization of non-adsorbed dyes. It was determined that the photocatalytic activity was highest at low dye concentration and high photocatalyst content. Additionally, it was determined that decolorization kinetics studies were compatible with the Langmuir-Hinshelwood model.
Synthesis and characterization of polymer microspheres and its application for phenol adsorption
(Desalination Publ, 2019-08-01) Özdemir, İnci; Kara, Ali; Tekin, Nalan; Olgun, Asim; KARA, ALİ; OLGUN, ASİM; Bursa Uludağ Üniversitesi/Fen-Sanat Fakültesi/Kimya Bölümü; 0000-0003-2457-6314; AAG-6271-2019; ABD-2316-2020
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.
The synthesis of covalent bonded single-walled carbon nanotube/polyvinylimidazole composites by in situ polymerization and their physical characterization
(Wiley, 2012-08) Tekin, Nalan; Beyaz, Saadet Kayıran; Şimşek, Eyüp; Lamari, Farida Darkrim; Çakmak, Gülbeden; Güney, Hasan Yüksel; Kara, Ali; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Bölümü.; AAG-6271-2019; 7102824859
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.
Water soluble poly(1-vinyl-1,2,4-triazole) as novel dielectric layer for organic field effect transistors
(Elsevier, 2011-03) Abbas, Mamatimin; Çakmak, Gülbeden; Tekin, Nalan; Güney, Hasan Yüksel; Arıcı, Elif; Sarıçiftçi, Niyazi Serdar; Kara, Ali; Uludağ Üniversitesi/Fen-Edebiyat Fakültesi/Kimya Anabilim Dalı.; AAG-6271-2019; 7102824859
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 AlO(x) 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.