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Processing of Polymer Nanofibers Through Electrospinng
El-Refaie Kenawy
Professor of Polymer Chemistry, Department of Chemistry, Faculty of Science,
University of Tanta, Tanta, EGYPT.
Electrospinning represent attractive approaches for polymer biomaterials processing with the opportunity for control over morphology, porosity, and compositions using simple equipment. Because electrospinning is one of the few techniques to prepare long fibers of nano- to micrometer diameter, great progress has been made in recent years.
The electrospinning process is used to make fine fibers with diameters in the range of nanometers to microns.
In this process, when force from an electric field at the surface of the polymer solution or melts is larger than the surface force, an electrically charged jet is formed and ejected. Electrospun fibers can be used to make nonwoven fabrics, reinforced fibers, support for enzymes, drug delivery systems, fuel cells, conducting polymers and composites.
The presentation would introduce the electrospinng technique and show few examples in the use of the technique to fabricate fibers for drug delivery.
Electrochemical Deposition of Nanostructured Thermoelectric Bismuth Telluride Thin Films
H. M. A. Soliman[1]a and Mamoun A. Muhammed b
a Institute of Advanced Technology and New Materials, Mubarak City for Scientific Research and Technology Applications, New Borg El-Arab City, P.O. Box 21934 Alexandria, Egypt
b Royal Institute of Technology, KTH, Department of Materials Science and Engineering Materials Chemistry, KTH-BRINELLVÄGEN 23, SE-100 44 STOCKHOLM, Sweden
Bismuth telluride films have been electrochemically deposited from solutions of bismuth nitrate pentahydrate and tellurium oxide in 1 M nitric acid (pH = 0) onto gold sputtered-aluminum substrates at 298 K. a conventional three-electrode cell was used with a platinum sheet as the counter electrode and saturated calomel electrode (SCE) as the reference electrode. The influence of a protic solvent (A) and a chelating agent (B) on the structure, morphology, compositional stoichiometry, grain size and adhesion properties were investigated. SEM, EDS and XPS were the structural and compositional characterization tools. The structure and morphology of films have been studied as a function of solvent concentration and the deposition conditions. A hexagonal nanostructured (average grain size of 48 nm) bismuth telluride film of a thickness > 300 mm with stoichiometry of Bi2Te3 was obtained.
Keywords: Nanostructured; thermoelectric; Bi2Te3; electrodeposition; protic solvent; chelating agent.
[1] Corresponding Author. Tel: +20-(0)3-459 3420; Fax: +20-(0)3-459 3423.
E-mail: hsolman@link.net (H.M.A. Soliman).
