Scopus İndeksli Yayınlar Koleksiyonu / Scopus Indexed Publications Collection

Permanent URI for this collectionhttps://hdl.handle.net/11147/7148

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Scopus Q: search.filters.scopusQuartile.Q2Subject: search.filters.subject.Polyvinyl alcohols

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  • Article
    Citation - WoS: 5
    Citation - Scopus: 7
    A Practical Approach for Optical Characterization of a Film Coated on the Optical Fiber
    (Academic Press Inc., 2017) Ekici, Çağın; Dinleyici, Mehmet Salih
    Phase Diffraction (PD) Phase Diffraction. which is a result of the interaction of light waves with a transparent object, is exploited to characterize precisely optical properties of dielectric films coated on the optical fiber without harming any feature of the sample. Typical fiber sensor applications require films coated on the side surface of the optical fiber and optical properties of that curved films are crucial for design purposes. In this study, three Polyvinyl Alcohol (PVA) films are prepared, their thicknesses are estimated based on the phase diffraction method by fitting experimental results with a mathematical model within 2.3% error. The outcomes of this practical method show good agreement with findings of the destructive Scanning Electron Microscopy (SEM) measurements. The method has the potential to allow real time monitoring abrupt changes of surrounding medium's properties and to examine coating quality (i.e. thickness uniformity) of the film.
  • Article
    Citation - WoS: 6
    Citation - Scopus: 6
    Hierarchial Coassembly of a Cyanine Dye in Poly(vinyl Alcohol) Fibrous Films by Electrospinning
    (American Chemical Society, 2013) Demir, Mustafa Muammer; Horzum, Nesrin; Özen, Bengisu; Özçelik, Serdar
    We report molecular aggregate formation of TTBC (1,1′,3,3′- tetraethyl-5,5′,6,6′-tetrachlorobenzimidazolocarbocyanine) in submicrometer-sized PVA (poly(vinyl alcohol)) fibers by electrospinning. The formation of the molecular aggregate is examined by solution and instrumental parameters of electrospinning. The precursor solution of PVA/TTBC, in the range of 0.016-0.065 wt % is subjected to electrospinning under an electrical field ranging from 0.95 to 1.81 kV cm-1. Both randomly deposited and uniaxially aligned fibers are achieved by using two parallel-positioned metal strips as counter electrode. Photoluminescence and polarized Fourier transform infrared spectroscopies are employed to determine spectral properties of the fibers. H-aggregates are formed within the electrospun fibers, regardless of their alignment, and H- and J-type aggregates coexist in the alternative spin-coated and the cast films. A strongly polarized photoluminescence emission is observed in the direction of uniaxially aligned fibers as a result of the orientation of the H-aggregates along the fiber axis. We demonstrate that electrospinning is a process capable of forming and orienting TTBC aggregates during the structural development of the polymer/dye nanofibers. These fibrous films may potentially find applications in optics and electronics.