Investigation on process parameters of electrospinning system through orthogonal experimental design

Electrospinning is a very simple and versatile method of creating polymer-based high-functional and high-performance nanofibers. But most of the investigations are not systematic and describe the electrospinning process without quantitative accuracy. Inconsistent and even opposite results have been reported, which has hindered the consistent interpretation of the experiments. Orthogonal experimental method was used to investigate qualitative and quantitative correlations between fiber characteristics (diameters and morphologies) and the processing and materials parameters. Uniform fibers can be obtained without any beads by proper selection of the processing parameters, and a lower glass transition temperature was observed for electrospun fibers than that of native polymer. Results of statistical analysis showed that significant influences were observed for polymer molecular weight and solution concentration on fiber diameters, and there were significant effects of polymer molecular weight, solution concentration, and solvent system on fiber morphologies. Meanwhile, solution concentration and polymer molecular weight, and polymer molecular weight and solvent system had obvious interaction effects. Regression analysis revealed quantitative relations of fiber diameters and beads percent, that is, Y-1 = 72.8X(1) - 8.1X(2) + 138.8, Y-2 = -3.2X(1) + 0.4X(2) + 60.5, where Y-1 is fiber diameter (nm), Y-2 beads percent X, solution concentration (%, w/w), and X-2 polymer molecular weight (kDa). Validation test showed that the experimental values of fiber size and beads percent were in good agreement with the calculated ones. Based on these results, optimal conditions could be obtained for predetermined diameters and morphologies for electrospun fibers. (c) 2006 Wiley Periodicals, Inc.