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    Construction of Nickel Hydroxide Based Electrode Material and Its Performance for Non-enzymatic Glucose Sensing Applications
    (Springer, 2025) Dulgerbaki, Cigdem
    Conventional nanomaterials are used in electrochemical glucose non-enzymatic sensing, but their widespread application is restricted by high costs and complex preparation procedures. This study explores the use of nickel hydroxide (Ni(OH)2), which was deposited onto the entire surface of a screen-printed gold electrode (SPGE) through one-step electrodeposition process, serving as an interface material for non-enzymatic glucose sensing. The surface morphology, composition and electrochemical properties of SPGE/Ni(OH)2 were investigated using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDX), elemental mapping, cyclic voltammetry (CV) and chronoamperometry (CA). CV and CA results revealed that SPGE/Ni(OH)2 exhibited excellent electrocatalytic activity towards glucose. The oxidation current was directly proportional to glucose concentrations ranging from 10 mu M to 200 mu M. Furthermore, the glucose sensor demonstrated a low detection limit of 1.8 mu M in a basic solution and exhibited excellent selectivity. With its facile preparation and reliable performance, this sensor is a promising candidate for the next generation non-enzymatic glucose diagnostic devices.
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    Development of Poly(2-Methyl Thioaniline)/Vanadium Pentoxide Hybrid Electrode Material for High Performance Supercapacitor Applications
    (Taylor & Francis Inc, 2023) Dulgerbaki, Cigdem
    To satisfy the constantly growing demand for energy, it is crucial to design electrode materials that have high specific capacitance and excellent reversibility to be used in applications such as portable electronics, backup power supplies, smart grids, hybrid vehicles, transportation and wearable electronics fields. This report presents a novel approach to creating such materials through the electrochemical deposition of a poly(2-methyl thioaniline)/vanadium pentoxide (PMTA/V2O5) hybrid material. The hybrid material was tested as a supercapacitor electrode material by means of cyclic voltammetry, galvanostatic charge/discharge and electrochemical impedance spectroscopy techniques. The PMTA/V2O5 hybrid demonstrated excellent charge-storage capabilities within a large potential window (-1.0 to 1.0 V), with a specific capacitance of 698 F/g at a current density of 1 A/g for samples that had a 1 mm thickness. This value is higher than the specific capacitance of V2O5 and resulted from the organic-inorganic synergistic effect between PMTA and V2O5. Facilitated charge-transfer between the two components owing to the presence of a strong electron-donating group (-SCH3) in PMTA led to a superior electrochemical performance of the PMTA/V2O5 hybrid. This strategy can be applied to produce thin films based on PMTA/V2O5, which have the potential to serve as active electrode material in supercapacitor devices.
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    Effects of silane-modified nano-CaCO3 particles on the mechanical properties of carbon fiber/epoxy (CF/EP) composites
    (Wiley, 2023) Durukan, Seyma Nur; Beylergil, Bertan; Dulgerbaki, Cigdem
    In this study, the effects of silane-treated nano-CaCO3 particles on the flexural, Mode-I, Mode-II and interlaminar shear strength (ILSS) properties of carbon fiber/epoxy composites are investigated experimentally. The surface of nano-CaCO3 particles is treated with a silane coupling agent, namely, (3-Glycidyloxypropyl) trimethoxysilane (GPTMS). Three-point bending, double cantilever beam (DCB), end-notch flexure (ENF), and short beam shear (SBS) tests are carried out on the prepared composite specimens according to the relevant ASTM requirements. The results show that with the dispersion of 5 wt% silane-treated nano-CaCO3 particles the flexural modulus, flexural strength, Mode-I fracture toughness, Mode-II fracture toughness, and ILSS values can be enhanced by 16.8%, 13.6%, 25.7%, 19.6%, and 19.8%, respectively, compared to reference composites. The storage modulus is also increased by about 15.3% with the silane-treated nano-CaCO3 particles. The silane-treated nano-CaCO3 particles had no significant effect on the glass transition temperature of the composites.
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    Investigation of the electrochemical behaviors of fibers containing new pyrazolo[5,1-c][1,2,4]triazine derivatives
    (Taylor & Francis Inc, 2023) Maslakci, Neslihan Nohut; Eren, Esin; Dulgerbaki, Cigdem; Yildirim, Fati; Oksuz, Aysegul Uygun
    Electrospun fibers of 7-methyl-4-phenyl-8-(4'-methoxy)phenylazopyrazolo[5,1-c][1,2,4]triazine-3-carboxylic acid ethyl ester (PCA-4) and 7-methyl-4-phenyl-8-(2'-methoxy)phenylazopyrazolo[5,1-c][1,2,4]triazine-3-carboxylic acid ethyl ester (PCA-2) were produced using electrospinning technique. Poly(methylmethacrylate) (PMMA) was used as support electrospun polymer. The morphological and chemical characterizations of the PCA-4/PMMA and PCA-2/PMMA electrospun fibers were carried out by scanning electron microscopy coupled with energy-dispersive X-ray spectroscopy analysis (SEM-EDX). The electrochemical behavior of the PCA-4/PMMA and PCA-2/PMMA fibers onto ITO electrodes was examined by cyclic voltammetry (CV) measurements. The new PCA-4/PMMA and PCA-2/PMMA fibers were used for phosphate anion sensing. PCA-4/PMMA fiber indicated the best current response to 0.2 M phosphate buffer solution at -0.67 V.
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    Iron oxide/poly(3,4-ethylenedioxythiophene): poly(styrene sulfonate) glassy carbon electrode as a novel label-free electrochemical microRNA-21 sensor
    (Taylor & Francis Inc, 2024) Dulgerbaki, Cigdem; Oksuz, Aysegul Uygun
    MicroRNAs (miRNAs), a type of non-protein-coding and small RNAs, are encouraging molecular biomarkers for prior diagnosis of the certain diseases. Here, an electrochemical sensor based on iron oxide/poly(3,4-ethylenedioxythiophene):poly(styrene sulfonate (Fe3O4/PEDOT:PSS) hybrid coated glassy carbon electrode (GCE) is reported to determine microRNA-21 (miRNA-21) as a biosensing platform based on hybridization event. The biosensor was characterized by cyclic voltammetry (CV) measurements. The Fe3O4/PEDOT:PSS demonstrated good sensing performance, including a wide detection range (0.1 pM-1 mu M) and a low detection limit (0.023 pM) for potential medical applications.
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    Mechanical performance of nanocalcite (nano-CaCO3 ) particle reinforced carbon fiber/epoxy (KF/EP) composites under different loading conditions
    (Pamukkale Univ, 2024) Beylergil, Bertan; Durukan, Seyma Nur; Dulgerbaki, Cigdem
    The aim of this study is to investigate the effects of nano calcite (nanoCaCO(3) ) particles on the mechanical properties of carbon fiber/epoxy (CF/EP) composites manufactured by vacuum -infusion process. For this aim, nano calcite (nano-CaCO3 ) particles at different loading ratios (1wt. %, 3wt. % and 5wt. %) were integrated into the epoxy matrix by pre -dispersion method. Then, reference and nano-CaCO3 reinforced CF/EP composites were manufactured by vacuum -infusion method. Short -beam shear, end -notch flexure (ENF) and Charpy impact tests were carried out on the prepared composite test specimens according to relevant ASTM standards. Additionally, the thermomechanical response of the composite specimens was determined via dynamic mechanical analysis (DMA). The fractured surfaces were examined by scanning electron microscopy (SEM). The results showed that the nano calcite particles could improve interlaminar shear strength (ILSS), Mode -II fracture toughness and Charpy impact strength by 17.4%, 34.1% and 10.0%, respectively, compared to the reference CF/EP composites. For these loading conditions, the optimum nano-CaCO3 amounts were determined as 1%, 5% and 3%, respectively. DMA results showed that the nano-CaCO3 particles had no significant effect on the glass transition temperature (T g ) of the composites.
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    Poly(3-methylthiophene)/Tungsten oxide hybrid materials for highly efficient electrochromic devices
    (Elsevier, 2021) Dulgerbaki, Cigdem; Oksuz, Aysegul Uygun
    Enhanced electrochemical and optical properties of poly(3-methylthiophene)/tungsten oxide (PMeT/WO3) hybrid nanostructure based electrochromic devices (ECDs) are presented. Hybrid nanostructures were prepared by electrodeposition technique in the presence of four different ionic liquids; 1-butyl-3-methylimidazolium tetrafluoroborate (BMIMBF4), 1-butyl-3-methylimidazolium hexafluorophosphate (BMIMPF6), 1-butyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide (BMIMTFSI) and 1-butyl-1-methylpyrrolidinium bis(trifluoromethylsulfonyl) imide (BMPTFSI). The electrochromic behaviors of the ECDs were investigated using cyclic voltammetry, chronoamperometry and transmittance measurements. PMeT/WO3/BMIMTFSI based ECD revealed excellent electrochromic properties of broad optical modulation (57.92%) and great coloration efficiency (398.32 cm2/C). Morphological structures of the thin films were examined by a scanning electron microscope (SEM), which showed that remarkable optical properties of PMeT/WO3 hybrid synthesized in BMIMTFSI medium can be attributed to the spongy network structure. The improved performance of the PMeT/ WO3 hybrid electrodes and the facile synthesis through electrodeposition method demonstrate a viable strategy for preparing fast assembling high-performance hybrid electrodes for a wide variety of electrochemical devices.