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    Electrical Characterization of Interdigitated Humidity Sensors Based on CNT Modified Calixarene Molecules
    (POLISH ACAD SCIENCES INST PHYSICS, 2013) Ozbek, C.; Culcular, E.; Okur, S.; Yilmaz, M.; Kurt, M.
    In this study, we report on the optimization and characterization of chloroform soluble calix[4]arene derivative as a humidity sensor based on electrical properties. Due to the fact that calix[4]arene molecules are nonconductive, we modified the calix[4]arene molecules with carbon nanotubes with electrostatic bond in order to increase the conductance of calix[4]arene molecule (5,11,17,23-tetra-ter-butyl-25,27-dehydrazinamidcarbonilmetoxy-26,28-dehydroxy-kalix[4]aren). Using photolithography technique, we fabricated interdigitated gold electrodes with 3 micrometers separation to investigate the electrical properties of carbon nanotubes modified calix[4]arene molecule where we used dropcast method to form a thin film of carbon nanotubes modified calix[4]arene molecule on the gold electrodes. Our reproducible experimental results indicated that the chloroform soluble carbon nanotubes modified calix[4]arene films have great potential for humidity sensing applications at room temperature operations. DOI: 10.12693/APhysPolA.123.461
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    Gas Sensing Properties of Carbon Nanotubes Modified with Calixarene Molecules Measured by QCM Techniques
    (POLISH ACAD SCIENCES INST PHYSICS, 2012) Mermer, Ö.; Okur, S.; Sümer, F.; Özbek, C.; Sayın, S.; Yılmaz, M.
    This study focuses on the characterization and optimization of calixarene modified carbon nanotube thin films for gas detection. Calixarene molecules were synthesized individually by considering their functional groups to attract the gas. Calixarene modified carbon nanotube based sensors were fabricated using drop-casting method on a quartz crystal microbalance gold electrode. Carbon monoxide, carbondioxide, oxygen and dry air were used as active gases for adsorption process, while high-purity nitrogen gas was used for desorption process. The selectivity and sensitivity of calixarene modified carbon nanotube are investigated in detail. Our experimental results show that functional calixarene modified carbon nanotube coated quartz crystal microbalance sensors are very sensitive and selective to gas of CO2 at room temperature operation.
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    Synthesis, FT-IR, FT-Raman, dispersive Raman and NMR spectroscopic study of a host molecule which potential applications in sensor devices
    (PERGAMON-ELSEVIER SCIENCE LTD, 2012) Kurt, M.; Karabacak, M.; Okur, S.; Sayin, S.; Yilmaz, M.; Sundaraganesan, N.
    The solid phase FT-IR, FT-Raman and dispersive Raman spectra of the host molecule which potential applications in sensor devices have been recorded in the region 400-4000 and 50-3500 cm(-1), respectively. The spectra were interpreted in terms of fundamentals modes, combination and overtone bands. The structure of the molecule was optimized and the structural characteristics were determined by density functional theory (DFF) using B3LYP method with 6-31G(d) basis set. The vibrational frequencies were calculated for the studied molecule by DFT method, and compared with the experimental frequencies, which yield good agreement between observed and calculated frequencies. Finally the calculation results were applied to simulate infrared and Raman spectra of the compound. Obtained these spectra also showed good agreement with observed spectra. The dipole moment, linear polarizability and first hyperpolarizability values were also computed. The linear polarizability and first hyperpolarizability of the studied molecule indicate that the compound is a good candidate of nonlinear optical materials. Crown Copyright (C) 2012 Published by Elsevier B.V. All rights reserved.