Research Project: Yeni Nanokompozit Malzemeler Üretimi
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Contributors
Funders
ID
TB.00008
Authors
Erkey, Can
Faculty Member
Publications
Synthesis of nanostructured materials using supercritical CO2: part II. chemical transformations
(Springer, 2012) Bozbağ, Selmi Erim; Erkey, Can; Şanlı, Deniz; Department of Chemical and Biological Engineering; Yes; College of Engineering
This article, the second part of our review series on the use of supercritical carbon dioxide (scCO(2)) for synthesis of nanostructured material deals with the production techniques that involve chemical transformations. Taking advantage of both solvent and anti-solvent tunable properties of scCO(2), many nanostructured materials including supported/unsupported nanoparticles, quantum nanodots, nanofilms, nanorods, nanofoams, and nanowires can be prepared. Furthermore, material surfaces can be functionalized using scCO(2). scCO(2) can also be used as a carbon source for the controlled synthesis of carbon nanotubes and fullerenes or as an oxygen source for metal oxide nanostructures. Moreover, materials produced using scCO(2) does not usually need additional purification or drying steps. Depending on surface properties, the morphology of the final material can be adjusted by tuning the process conditions and the reactant concentrations.
Aerogel-copper nanocomposites prepared using the adsorption of a polyfluorinated complex from supercritical CO2
(Kluwer Academic Publishers, 2012) Bozbağ, Selmi Erim; Erkey, Can; Kostenko, Svetlana O.; Kurykin, Michael A.; Khrustalev, Victor N.; Khokhlov, Alexei R.; Zhang, Lichun; Aindow, Mark; Department of Chemical and Biological Engineering; Yes; College of Engineering
A supercritical deposition method has been used to synthesize aerogel-copper nanocomposites. Carbon, resorcinol-formaldehyde, and silica aerogels (CAs, RFAs, and SAs) were impregnated with a new polyfluorinated copper precursor (CuDI6), which has a high solubility in supercritical carbon dioxide (scCO(2)). Adsorption isotherms of CuDI6 onto various aerogels from scCO(2) were determined at 35 degrees C and 10.6 MPa using a batch method which is based on the measurement of the fluid phase concentration. The relative affinity between CuDI6 and different aerogels changed in the following order: CA > RFA > SA. The effect of temperature on the adsorption isotherms for the CuDI6-CO2-CA system was also studied at 35 and 55 degrees C and at a CO2 density of 736.1 kg/m(3). The CuDI6 uptake at a particular CuDI6 concentration increased with increasing temperature. Adsorbed CuDI6 was found to convert into Cu and Cu/Cu2O nanoparticles on the aerogel supports after chemical or thermal treatments at ambient pressure and at temperatures ranging from 200 to 400 degrees C.
Synthesis of nanostructured materials using supercritical CO2: part I. physical transformations
(Springer, 2012) Bozbağ, Selmi Erim; Erkey, Can; Şanlı, Deniz; Department of Chemical and Biological Engineering; Yes; College of Engineering
Nanostructured materials have been attracting increased attention for a wide variety of applications due to their superior properties compared to their bulk counterparts. Current methods to synthesize nanostructured materials have various drawbacks such as difficulties in control of the nanostructure and morphology, excessive use of solvents, abundant energy consumption, and costly purification steps. Supercritical fluids especially supercritical carbon dioxide (scCO(2)) is an attractive medium for the synthesis of nanostructured materials due to its favorable properties such as being abundant, inexpensive, non-flammable, non-toxic, and environmentally benign. Furthermore, the thermophysical properties of scCO(2) can be adjusted by changing the processing temperature and pressure. The synthesis of nanostructured materials in scCO(2) can be classified as physical and chemical transformations. In this article, Part I of our review series, synthesis of nanostructured materials using physical transformations is described where scCO(2) functions as a solvent, an anti-solvent or as a solute. The nanostructured materials, which can be synthesized by these techniques include nanoparticles, nanowires, nanofibers, foams, aerogels, and polymer nanocomposites. scCO(2) based processes can also be utilized in the intensification of the conventional processes by elimination of some of the costly purification or separation steps. The fundamental aspects of the processes, which would be beneficial for further development of the technologies, are also reviewed.
