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Carbon nanofibers were produced from a polyacrylonitrile/N,N-dimethylformamide precursor solution by an electrospinning process and later pyrolysis at temperatures ranging from 500 to 11008C in an N 2 atmosphere for about 1 h. The morphological structure of the nanofibers was studied with scanning electron microscopy. Scanning electron microscopy images of carbonized polyacrylonitrile nanofibers without a gold coating showed that the carbonized polyacrylonitrile nanofibers possessed electrical properties. The thermal behavior of the nanofibers was studied with thermogravimetric analysis. An indirect four-point-probe method was used for the measurement of the conductivity of nanofiber mats. The conductivity increased sharply with the pyrolysis temperature.

Response surface methodology (RSM) was used to obtain a more systematic understanding of the electrospinning conditions of polyamide 6 solutions. This method was used to establish a quantitative basis for the relationships between the electrospinning parameters such as applied electric field, the polymer concentrations, the rate of injection and nozzle-collector distance with the diameter of the produced nanofibers, and to predict the optimum conditions for electrospinning to produce nanofibers with controlled size. A response function was empirically determined by central composite design (CCD) using fiber diameter as an observed response and the electrospinning parameters as variables. The relationship between the response and the variables is visualized by a response surface or contour plots. The study of the graphical representations of contour plots, prediction formulas and prediction profiler can predict the operating conditions necessary to generate nanofibers with the desired diameters.

In this work, nanofibers of chitosan/poly (ethylene oxide) (PEO) with an average fiber diameter from a few microns down to about 30 nm and a narrow size distribution were fabricated by a fast electrospinning process using a handheld electrospinning device. It was found that the matrix with a formulation of chitosan/PEO ratio of 90/10 (w/w) and 0.3% Triton V R X-100 retained excellent integrity of the fibrous structure in 0.5M acetic acid solution. The characterization of nanofibrous structure by scanning electron microscope (SEM) imaging showed the homogeneity of nanofibrous structure without consid-erable bead-like structures. The excellent electrospinnability of the current formulation represents electrospinning of natural biopolymer chitosan as a useful process in various biomedical applications, especially as potential wound dressing agents. Nonwoven mats and polymer solutions with composition chitosan/PEO ratio of 90/10 and 60/40 showed excellent antibacterial activity against E. coli and P. aeruginosa. V C 2011 Wiley Periodicals, Inc. J Appl Polym Sci 000: 000-000, 2011

Highly sulfonated single-walled carbon nanotube-catalyzed synthesis of 14-aryl-14Hdibenzo [a,j]xanthenes in excellent yields and very short reaction times. Sulfonated singlewalled carbon nanotubes are prepared using a chemical and simple process and it characterized by Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), Raman spectroscopy, Thermal gravimetric analysis (TGA) and acid-base titration. The sulfonated single-walled carbon nanotube was easily separated by simple filtration and was recycled eight consecutive times without any loss in its activity.