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  • Küçük Resim
    Öğe
    Effect of multi wall carbon nanotube on electrical properties 4-[4-((S)-Citronellyloxy)benzoyloxy]benzoic acid liquid crystal host
    (Elsevier Sci Ltd, 2015) Denktaş, Cenk; Ocak, Hale; Okutan, M.; Yıldız, Alptekin; Eran, Belkız Bilgin; Köysal, Oğuz
    Dielectric properties, conductivity mechanisms and current voltage characteristics of Multi Wall Carbon Nanotube (MWCNT) doped and pure Liquid Crystal (LC) material was investigated using impedance spectroscopy method in the frequency range of 100 Hz to 15 MHz. Liquid crystalline material, 4-[4-((S)-Citronellyloxy)benzoyloxy]benzoic acid (CBBA) as a host material and MWCNT was used as doping material in this study. In order to observe the effects of doping MWCNT into LC on dielectric properties, an MWCNT material was doped into CBBA structure with 1 wt%. Real part of dielectric constants (epsilon'), imaginary part of dielectric constant (epsilon ''), i.e. dielectric loss, dissipation factor/dielectric loss tangent (tan delta) were obtained for the pure and doped LC samples. In addition, dielectric strength (bads), negative dielectric anisotropy (Delta epsilon da), absorption coefficients (alpha) and relaxation times (tau) were calculated from the empirical data. I-V characteristics of pure LC and doped LC structures were carried out at micro-current levels by current-voltage measurements. (C) 2015 Elsevier Ltd. All rights reserved.
  • Küçük Resim
    Öğe
    Investigation of the dielectric and optic properties of rosehip seed extract loaded hydrogels
    (Elsevier B.V., 2023) Okutan, M.; Coşkun, R.; Yalçın, O.; Babuçoğlu, A. C.; Demir, Ahmet
    Rosehip seed (RS) extract-loaded hydrogel samples RS1 (poly(AMPS-co-MBAAm), RS2 (poly(AMPS- co - CrA- co - MBAAm)), RS3 (poly(AMPS - co - MAA - co - MBAAm)) and RS4 (poly(AMPS -co - IA - co- MBAAm)) were prepared to examine their structural and optical properties. Furthermore, frequency and bias voltage evolution of dielectric and electrical parameters were analyzed using impedance spectroscopy (IS) for all samples at room temperature (RT). Fluctuating and self-consistent results were obtained in the Ultraviolet–visible (UV) spectrum of the samples. The conductivity mechanisms were determined by calculating the s parameters of all samples for different regions. The complex impedance, capacitance, phase angles, dielectric constant, tangent factor, electric modulus, and frequency variation of ionic conductivity for the rosehip seed loaded hydrogel were successfully analyzed in detail using IS in the broadband frequency range. The increase in ionic conductivity of the RS-doped hydrogel with increasing frequency was attributed to its ability to exhibit the Langevin equivalent of Brownian motion in viscoelastic fluids, surface/bulk Maxwellian stress relaxation behavior, and the validity of the Stokes-Einstein relationship in biological fluids. In particular, the capacitive effect observed as a result of the Cole-Cole diagrams of the dielectric constant adapting to Smith Chat and the equivalent RC circuit allowed the material to be used as a capacitor. © 2022