Browsing by Subject "Polymeric matrices"

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    Excitation dependent recombination studies on SnO2/TiO2 electrospun nanofibers
    (Royal Society of Chemistry, 2015) Babu, V. J.; Vempati S.; Ertas Y.; Uyar, Tamer
    Poly(vinyl acetate) (PVAc)/TiO2 nanofibers, PVAc/SnO2 nanoribbons and PVAc/SnO2-TiO2 nanoribbons were produced via electrospinning. TiO2 nanofibers and SnO2 nanoribbons were obtained by removal of the polymeric matrix (PVAc) after calcination at 450 °C. Interestingly, PVAc/SnO2-TiO2 nanoribbons were transformed into SnO2-TiO2 nanofibers after calcination under the similar conditions. Fiber morphology and elemental mapping confirmed through SEM and TEM microscope techniques respectively. The X-ray diffraction measurements suggested the presence of anatase TiO2 and rutile SnO2 and both were present in the SnO2-TiO2 mixed system. Systematic photoluminescence studies were performed on the electrospun nanostructures at different excitation wavelengths (λex1 = 325, λex2 = 330, λex3 = 350, λex4 = 397 and λex5 = 540 nm). We emphasize that the defects in the SnO2-TiO2 based on the defect levels present in TiO2 and SnO2 and anticipate that these defect levels may have great potential in understanding and characterizing various semiconducting nanostructures.
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    ItemOpen Access
    Fast-dissolving, prolonged release, and antibacterial cyclodextrin/limonene-inclusion complex nanofibrous webs via polymer-free electrospinning
    (American Chemical Society, 2016) Aytac Z.; Yildiz, Z. I.; Kayaci-Senirmak, F.; S. Keskin, N. O.; Kusku, S. I.; Durgun, Engin; Tekinay, T.; Uyar, Tamer
    We have proposed a new strategy for preparing free-standing nanofibrous webs from an inclusion complex (IC) of a well-known flavor/fragrance compound (limonene) with three modified cyclodextrins (HPβCD, MβCD, and HPγCD) via electrospinning (CD/limonene-IC-NFs) without using a polymeric matrix. The experimental and computational modeling studies proved that the stoichiometry of the complexes was 1:1 for CD/limonene systems. MβCD/limonene-IC-NF released much more limonene at 37, 50, and 75 °C than HPβCD/limonene-IC-NF and HPγCD/limonene-IC-NF because of the greater amount of preserved limonene. Moreover, MβCD/limonene-IC-NF has released only 25% (w/w) of its limonene, whereas HPβCD/limonene-IC-NF and HPγCD/limonene-IC-NF released 51 and 88% (w/w) of their limonene in 100 days, respectively. CD/limonene-IC-NFs exhibited high antibacterial activity against E. coli and S. aureus. The water solubility of limonene increased significantly and CD/limonene-IC-NFs were dissolved in water in a few seconds. In brief, CD/limonene-IC-NFs with fast-dissolving character enhanced the thermal stability and prolonged the shelf life along with antibacterial properties could be quite applicable in food and oral care applications.