Browsing by Author "Yeşilöz, Gürkan"
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Item Open Access Novel size-tunable and straightforward ultra-small nanoparticle synthesis in a varying concentration range of glycerol as a green reducing solvent(American Chemical Society, 2023-08-08) Munir, Iqra; Yeşilöz, GürkanDespite all the possibilities available so far for the synthesis of nanoparticles (NPs), synthesizing ultra-small (<10 nm) monodispersed particles is still demanding. Getting a particular size with a straightforward method is a trial-and-error approach. To explore this prospective, in the current study, we have introduced a protocol which offers a varying concentration range of glycerol to successfully generate the NPs of repeatable and consistent particle size in each synthesis, thus giving an alternative from lengthy tentative preparations and/or testing protocols. Since synthesizing controlled sized nanoparticles in aqueous medium is somewhat difficult as the balance of particle growth and nucleation is challenging to control, herein, we used a polyol method with glycerol both as a solvent medium as well as reducing species for silver nitrate, as an example model ion source, to execute the nanoparticle synthesis. In order to maintain the stability of the synthesized NPs, polyvinylpyrolidone (PVP) was added as a stabilizer. The synthesis, monodispersity, and stability were confirmed using techniques such as UV–vis spectroscopy, Fourier transform infrared spectroscopy (FTIR), dynamic light scattering (DLS), and X-ray powder diffraction (XRD), while morphological analysis and ultra-small size validation were conducted using TEM, SEM, and AFM. Interestingly, in the various concentrations of glycerol solution used (10–100%), we have observed a tunable linear size range to obtain ultra-small nanoparticles (<10 nm) up to 60% glycerol, while further increasing the glycerol component increased the size approximately to ∼160 nm, providing tunable properties in this synthesis procedure. Hence, this study provides a distinct possibility to obtain ultra-small nanoparticles with a tunable size feature for further applications in numerous fields.Item Embargo One-step synthesis of ultrasmall nanoparticles in glycerol as a promising green solvent at room temperature using omega-shaped microfluidic micromixers(ACS Publications, 2023-11-28) Jahangir, Robab; Munir, Iqra; Yeşilöz, GürkanDespite innovations in the synthesis protocol of nanoparticles (NPs), the size distribution and uniformity of particles still remain as crucial attributes. Homogeneous and rapid nucleation is a critical phenomenon to obtain monodisperse nanoparticles. Herein, we have carried out the synthesis of metal nanoparticles in a customized microfluidic (MF) chip, with 18 omega-shaped micromixers, by using glycerol as a promising green solvent and reducing agent at various concentrations (10-80%), and simultaneous comparison of the results from batch synthesis. Initially, mixing characterization for 10-80% glycerol was obtained by adjusting the Peclet (Pe) number. Further, the effect of the Pe number, time, and concentrations of polyvinylpyrrolidone, metal source, and glycerol on the NP size was investigated. Interestingly, the experimental findings depicted that by varying different parameters, the spherical nanoparticles with an average ultrasmall particle diameter of <2 nm were obtained at all glycerol concentrations (10-80%), as compared to batch synthesis (giving a yield of ∼10-fold larger particles). The mixing efficiency in this MF chip design was analyzed by using a fluorescent dye in glycerol, while the particle morphology and size were characterized by using dynamic light scattering, transmission electron microscopy, and ultraviolet-visible spectroscopy. Hence, compared to the conventional benchtop-assisted NP synthesis, this study unveils the significant effect of the microfluidic technique on the synthesis of ultrasmall and homogeneous nanoparticles in a single step, using an environmentally friendly solvent.