Fabrication of high performance chitosan/polyvinyl alcohol nanofibrous mat with controlled morphology and optimised diameter

The main aim of the present study is to fabricate a high performance chitosan (CS)/polyvinyl alcohol (PVA) electrospun nanofibrous mat having a high content of CS, a desirable morphology (defect-free structure) and a superfine diameter (approx. 100 nm). As electrospinning of constructions containing CS is known as a complex process, it is necessary to employ systematic control and optimisation of processes. In this regard, the controlling and optimisation of the processes were followed by two subsequent stages. In the first stage, morphology controlling parameters were investigated with respect to CS/PVA solution characteristics including CS concentration, solvent concentration and the content of the partner polymer (PVA). In the second stage, in order to attain the finest possible diameter, process modelling was carried out in terms of processing parameters (applied voltage, nozzle-collector distance and feed rate) by using response surface methodology (RSM). According to the experimental results of the first stage, the best morphological structure containing the highest content of CS was obtained under 3% (w/v) of CS, concentrated acetic acid (90%) and 20% weight ratio of PVA. The significance of the applied model was confirmed by statistical approaches and the effect of the selected parameters on the diameter was studied. Experimentally, the finest diameter of 104 +/- 18 nm was obtained under optimised processing parameters determined from the RSM technique. The experimental value of the nanofibre diameter was in close agreement with the predicted value in which the prediction error of the model was only 1.92% confirming the high reliability of the applied model.