Browsing by Subject "Coprecipitation method"

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Open Access
Antibacterial electrospun poly(lactic acid) (PLA) nanofibrous webs incorporating triclosan/cyclodextrin inclusion complexes
(2013) Kayaci F.; Umu O.C.O.; Tekinay, T.; Uyar, T.
Solid triclosan/cyclodextrin inclusion complexes (TR/CD-IC) were obtained and then incorporated in poly(lactic acid) (PLA) nanofibers via electrospinning. α-CD, β-CD, and γ-CD were tested for the formation of TR/CD-IC by a coprecipitation method; however, the findings indicated that α-CD could not form an inclusion complex with TR, whereas β-CD and γ-CD successfully formed TR/CD-IC crystals, and the molar ratio of TR to CD was found to be 1:1. The structural and thermal characteristics of TR/CD-IC were investigated by 1H NMR, FTIR, XRD, DSC, and TGA studies. Then, the encapsulation of TR/β-CD-IC and TR/γ-CD-IC in PLA nanofibers was achieved. Electrospun PLA and PLA/TR nanofibers obtained for comparison were uniform, whereas the aggregates of TR/CD-IC crystals were present and distributed within the PLA fiber matrix as confirmed by SEM and XRD analyses. The antibacterial activity of these nanofibrous webs was investigated. The results indicated that PLA nanofibers incorporating TR/CD-IC showed better antibacterial activity against Staphylococcus aureus and Escherichia coli bacteria compared to PLA nanofibers containing only TR without CD-IC. Electrospun nanofibrous webs incorporating TR/CD-IC may be applicable in active food packaging due to their very high surface area and nanoporous structure as well as efficient antibacterial property. © 2013 American Chemical Society.
Open Access
Facile route to produce spherical and highly luminescent Tb3+doped Y2O3 nanophosphors
(Elsevier, 2017) Kumar, D.; Sharma, M.; Haranath, D.; Pandey, O. P.
Terbium doped yttrium oxide (Y2O3:Tb3+) nanophosphor has been synthesized via a facial yet modified co-precipitation method. To get maximum luminescence output from Y2O3:Tb3+nanophosphors, surfactants namely, Cetyl trimethylammonium bromide (CTAB) and Trioctylphosphine oxide (TOPO) were added during synthesis. Further, it has been observed that combined addition of surfactant (CTABï¿½+ï¿½TOPO) at the time of synthesis has resulted in nearly spherical morphology of the nanophosphor. Furthermore, these optimized material are observed to have enhanced integrated photoluminescence (PL) intensity of ∼23% as compared to the one synthesized without the addition of any surfactant. The results are further supported by detailed structural and optical studies. Optimum use of surfactants during synthesis shows for the first time that both nano-sized distribution and high crystallinity can be achieved simultaneously which has resulted in bright green emission in Tb3+doped Y2O3nanophosphors.
Open Access
Fast and quick degradation properties of doped and capped ZnO nanoparticles under UV-Visible light radiations
(Elsevier Ltd, 2016) Mittal, M.; Sharma, M.; Pandey, O. P.
Undoped and Manganese (Mn) doped zinc oxide (ZnO) (Zn1- xMnxO, x=0.005, 0.01, 0.015 and 0.02) nanoparticles (NPs) capped with (1.0%) Thioglycerol (TG) has been successfully synthesized by co-precipitation method. Optical and morphological studies have been done for photophysical and structural analysis of synthesized materials. The photocatalytic activity of undoped and Mn doped ZnO NPs were investigated by degradation of crystal violet (CV) dye under UV-Visible light radiations. It has been found that Mn (1.0%) doping concentration is optimal for photophysical and photocatalytic properties. When the pH of as synthesized optimum doped ZnO NPs varied from natural pH i.e. from 6.7 to 8.0 and 10.0, the degradation of CV dye increases from 92% to 95% and 98% in 180min respectively. Further on increasing the pH of optimum doped synthesized NPs to 12.0, almost 100% degradation has been achieved in 150min. Optimum doped photocatalyst synthesized at pH-12.0 has also effectively degraded the CV dye solution in acidic and basic medium thus showed its utility in various industries. However, it has been found that 100% of CV dye quickly degraded in 30min when only 1.0% of hydrogen peroxide (H2O2) was introduced along with optimized NPs synthesized at pH-12. Kinetic studies show that the degradation of CV dye follows pseudo first and second-order kinetic law. Further an industrial anionic polyazo Sirius red F3B (SRF3B) dye has been degraded to 100% with optimized NPs synthesized at pH-12.0 in 15min only.