Application of response surface methodology in assessing the effect of electrospinning parameters on the morphology of polyethylene oxide/polyacrylonitrile blend nanofibers containing graphene oxide

Electrospun polyethylene oxide/polyacrylonitrile/graphene oxide (PEO/PAN/GO) membranes were produced for using as polymer electrolytes in dye-sensitized solar cells. The effects of material and process parameters on the diameter of the fibers were evaluated using Box-Behnken experimental design to obtain a quantitative relationship between selected parameters (namely GO content, solution concentration, feed rate) and responses (nanofibers diameters and their standard deviation). The importance of the parameters and their interactions were investigated through the analysis of variance. The model was consequently used to find the optimal conditions that yield the minimum nanofiber diameter. The morphology and nanofiber diameter were investigated by scanning electron microscopy. Fibers with diameters ranging from 103 to 340nm were obtained. It was observed that the nanofiber diameter increased with solution concentration and feed rate. The GO incorporation caused a reduction of the nanofiber diameters. Nanofibers with smaller diameters and standard deviations could be obtained at lower solution concentrations and feed rates. Based on the desirability function, the optimized factors for minimum nanofiber diameter were found as 1wt% GO, 17w/v% solution concentration and 1ml/h feed rate. Finally, the thermal and electrochemical properties of the optimized sample were compared with the pristine PEO/PAN membrane electrolyte. The measured electrolyte uptake and ionic conductivity of the membranes showed a significant improvement in the presence of GO nanosheets.