Effect of organic solvents in morphology and mechanical properties of electrospun polyvinylpyrrolidone fibers

In this work, the electrospinning technique was used to obtain fibers for mechanical characterization. polyvinylpyrrolidone (PVP) was combined with organic solvents (ethanol and dimethylformamide (DMF)) to generate solutions, looking for the appropriate parameters to obtain fibers with the best morphology and the best mechanical properties. Starting from previous investigations to find the adequate percentages of solvent and PVP, several solutions were made, varying the different parameters like voltage, flow, tip collector distance. Seeking to obtain acceptable samples, the diameter was measured in a scanning electron microscope (SEM). The elastic modulus was measured for the fibers with the best aspect. Mechanical properties were measured in an atomic force microscope (AFM) with the Hertz contact method and the data were approximated to its mathematical model. The solutions that resulted in the best morphological properties were: ethanol - 8% PVP, DMF – 14% PVP, 70% ethanol - 30% DMF - 8% PVP, with diameters in the micrometer range of 1.6, 1.22 and 1.35 respectively, and elastic modulus of 40.08 MPa, 8.8 MPa and 32.78 MPa correspondingly. An analysis of all the parameters influencing the process was performed and an analysis of the influence of the solvents, based on the data of the elastic moduli was carried out.