Yazar "Capan, Rifat" seçeneğine göre listele

Listeleniyor 1 - 8 / 8
  • [ X ]
    Öğe
    Electrical properties of alternating acid and amino substituted calixarene Langmuir-Blodgett thin films
    (Pergamon-Elsevier Science Ltd, 2020) Ozbek, Zikriye; Davis, Frank; Capan, Rifat
    The Langmuir-Blodgett (LB) alternate layer fabrication technique provides one of the most effective methods to fabricate organic thin films in the nanoscale. The structure of these thin films could be controlled at the molecular scale by spreading a monolayer on an air-water interface followed by sequential transferring of this layer onto a selected solid substrate. These films can be utilized within optical, electrical and biological applications in many different fields. Within this paper, two calix[4]arenes containing either carboxylic acid or amino substituents were utilised to prepare multilayer LB films and to study the electrical characteristic of these films using I-V and C-f measurements. The resultant calix[4]acid/amine multilayers demonstrated a highly non-linear I-V behaviour which obeys a Schottky conduction mechanism.
  • [ X ]
    Öğe
    Fabrication of Langmuir-Blodgett thin films of calix[4]arenes and their gas sensing properties: Investigation of upper rim para substituent effect
    (Elsevier Science Sa, 2014) Ozmen, Mustafa; Ozbek, Zikriye; Buyukcelebi, Sumeyra; Bayrakci, Mevlut; Ertul, Seref; Ersoz, Mustafa; Capan, Rifat
    This study reports the characterization and organic vapor sensing properties of Langmuir-Blodgett (LB) thin films of calix[4] arene derivatives that contain different numbers of tert butyl groups on their upper rims. Surface pressure-area isotherms show that very stable monolayers are formed at the air-water interface. The LB films are deposited onto different substrates, which allowed us to characterize the films by contact angle measurements, quartz crystal microbalance (QCM), scanning electron microscopy (SEM), and atomic force microscopy (AFM). The results indicate that good quality, uniform LB films can be prepared with transfer ratios of over 0.95. Meanwhile, our QCM results show that the deposition of LB film layers depends heavily on the number of p-tert-butyl groups and calix[4]arene with four p-tert-butyl groups yields the highest slope with a mass value of 1145 ng per layer. Furthermore, our AFM and SEM studies reveal a dense surface morphology for all prepared LB films. The kinetic response of calix[4]arenes containing p-tert-butyl groups and without p-tert-butyl groups as an LB film to chloroform, benzene, toluene, and ethanol vapors were investigated as a function of time. After attaching tert-butyl groups onto the calix[4]arene structure, the response of LB film to chloroform vapor increased. LB films of compounds 1-4 yield a response to all vapors and more often select chloroform with a larger, faster, and more reproducible response. We thus conclude that these calix[4]arenes could be applied to research concerning vapor sensing devices operating at room temperature. (C) 2013 Elsevier B.V. All rights reserved.
  • [ X ]
    Öğe
    Humidity effect on real-time response of tetranitro-oxacalix[4] arene-based surface plasmon resonance (SPR) acetone sensor at room temperature
    (Elsevier Gmbh, 2023) Sen, Sibel; Onder, Ferah Comert; Capan, Rifat; Ay, Mehmet; Erdogan, Cansu Ozkaya
    We report the effect of humidity on the acetone sensitivity of nano-sized thin films obtained by spin coating the oxacalix[4]arenes(1,3) molecules on suitable substrates in this work. The surface morphologies and volatile organic compound (VOC) sensor properties of spin-coated thin films were examined using atomic force microscopy (AFM) and surface plasmon resonance (SPR), respectively. It was determined that the sensitivities calculated from the measurements performed using a mixture of acetone and water vapor were 14% and 11% incorrect for the 1 and 3 thin film sensors, respectively, compared to those performed with dry air and acetone mixture.
  • [ X ]
    Öğe
    Langmuir-Blodgett thin film for chloroform detection
    (Elsevier Science Bv, 2015) Capan, Rifat; Goktas, Hilal; Ozbek, Zikriye; Sen, Sibel; Ozel, Mehmet Emin; Davis, Frank
    Calix[4]resorcinarene (C11TEA) molecules could be deposited as an LB film by the Langmuir-Blodgett (LB) technique onto suitable substrates. Surface plasmon resonance (SPR) and UV-vis spectroscopy were employed for the characterization of these LB films. A high quality and uniform Langmuir monolayer from the water surface can be transferred onto a glass or gold coated substrates with a transfer ratio of over 95%. Thickness and refractive index values of the resultant LB films were measured using surface plasmon resonance with a value of 1.04nm per layer and 1.4 respectively. For the sensing application towards chloroform, this LB film yields a fast and almost fully reversible response to chloroform in few seconds. (C) 2015 Elsevier B.V. All rights reserved.
  • [ X ]
    Öğe
    Preparation and gas sensing properties of Langmuir-Blodgett thin films of calix[n]arenes: Investigation of cavity effect
    (Elsevier Science Sa, 2014) Ozmen, Mustafa; Ozbek, Zikriye; Bayrakci, Mevlut; Ertul, Seref; Ersoz, Mustafa; Capan, Rifat
    Characterization and organic vapor sensing properties of Langmuir-Blodgett (LB) thin films of calix[n]arene (n=4, 6, 8) derivatives are reported in this work. Surface pressure-area isotherm graph shows that very stable monolayers are formed at the water surface. The results indicate that good quality, uniform LB films can be prepared with a transfer ratio of over 0.95. Calix[n]arene LB films have been characterized by contact angle measurements, quartz crystal microbalance (QCM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). LB film of calix[8]arene which has the largest cavity yields a gradient with a mass value of 773 ng per layer according to the QCM results. AFM and SEM images showed a dense surface morphology obtained for all samples. QCM system was used for the measurement of sensor response against chloroform, benzene, toluene and ethanol vapors. These LB film samples yield a response to all vapors with a large, fast, and reproducible due to the adsorption of vapors into the LB film structures. Among them, calix[8]arene LB film has higher sensitivity toward the organic vapors because of a large cavity size. This study can be concluded that the cavity size of calix[n]arene molecule could have an important role in the research area of room temperature vapor sensing devices. (C) 2014 Elsevier B.V. All rights reserved.
  • [ X ]
    Öğe
    Preparation of Langmuir-Blodgett thin films of calix[6]arenes and p-tert butyl group effect on their gas sensing properties
    (Elsevier Science Bv, 2015) Ozmen, Mustafa; Ozbek, Zikriye; Bayrakci, Mevlut; Ertul, Seref; Ersoz, Mustafa; Capan, Rifat
    Organic vapor sensing properties of Langmuir-Blodgett (LB) thin films of p-tert-butyl calix[6]arene and calix[6]arene, and their certain characterization are reported in this work. LB films of these calixarenes have been characterized by contact angle measurement, quartz crystal microbalance (QCM), scanning electron microscopy (SEM) and atomic force microscopy (AFM). QCM system was used for the measurement of sensor response against chloroform, benzene, toluene and ethanol vapors. Forming of stable monolayers was observed at the water surface using surface pressure-area isotherm graph. The results indicate that good quality, uniform LB films can be prepared with a transfer ratio of over 0.95. Due to the adsorption of vapors into the LB film structures; they yield a response to all vapors as of large, fast, and reproducible. (C) 2015 Elsevier B.V. All rights reserved.
  • [ X ]
    Öğe
    Swelling behavior of pyrene-labelled polystyrene LB thin film exposed to various volatile organic vapors
    (Elsevier Science Sa, 2014) Ozbek, Zikriye; Erdogan, Matem; Capan, Rifat
    In this work thin films of pyrene-labelled polystyrene (PS) prepared Langmuir-Blodgett (LB) film technique are characterized by UV-visible spectroscopy, Atomic Force Microscopy (AFM) and Surface Plasmon Resonance (SPR). The sensing behaviors of the films were investigated with respect to volatile organic compounds (VOCs) at room temperature. The sensing responses of the films against VOCs (chloroform, benzene, toluene and ethanol) were measured by SPR method. In addition, the effects of film morphology and gas sensing properties were discussed. It was found that the PS films exhibited good response, reversibility, stability and faster response and recovery characteristic to VOCs. The changes in reflectivity implied the swelling behavior of PS thin film during adsorption and can be explained by the capture of organic vapor molecules. Fick's law for early-time diffusion was adopted to quantify real time SPR data for the swelling processes. It was observed that diffusion coefficients (D) for swelling obeyed the t(1/2) law and could be correlated with the VOCs used. The response of PS films to the choosed VOCs has been investigated in conditions of physical properties of the solvents, and the films were obtain to be largely sensitive to chloroform vapor compared to other studied vapors. (C) 2014 Elsevier B.V. All rights reserved.
  • [ X ]
    Öğe
    Thin Film Properties and the Detection Volatile Organic Compounds of C-Methylcalix(4)Resorcinarene
    (Amer Inst Physics, 2018) Sen, Sibel; Capan, Rifat; Turker, Gulen
    C-Methylcalix(4) resorcinarene (CM4RA) molecule fabricated as a thin film using spin coating method was studied for an application as a sensing membrane for the detection of volatile organic compounds. The optical properties of the CM4RA films were elucidated using UV-vis spectroscopy. In addition surface plasmon resonance technique (SPR) was employed to characterize the thin film deposition process of the CM4RA thin film. Sensing properties and the film thickness of these calixresorcinarene spun films were determined from SPR measurement. Sensing measurement results showed a fast response and recovery times with a reversible response in the optical behaviour of thin films of this material. Our results can be concluded that thin film fabricated using CM4RA molecule is demonstrating a good candidate for room temperature vapour sensing application.