Tuning the properties of PVDF or PVDF-HFP fibrous materials decorated with ZnO nanoparticles by applying electrospinning alone or in conjunction with electrospraying

Abstract

Novel composite nanofibrous materials of poly(vinylidene fluoride) (PVDF) or poly(vinylidene fluoride-cohexafluoropropylene) (PVDF-HFP) and ZnO nanoparticles were prepared by conjunction of electrospinning and electrospraying techniques. Simultaneous electrospinning of concentrated solution of PVDF or PVDF-HFP and electrospraying of suspension of ZnO in diluted PVDF or PVDF-HFP solution enable the preparation of materials consisting of fibers on which ZnO was deposited on the fibers’ surface (design type “on”). These fibrous materials were compared with materials consisting of PVDF or PVDF-HFP fibers in which ZnO was incorporated in the fibers (design type “in”) and which were obtained by one-pot electrospinning of a suspension of ZnO nanoparticles in concentrated PVDF or PVDF-HFP solution. The fiber morphology and the presence of ZnO “in” or “on” the fibers were observed by scanning electron microscopy (SEM) and by transmission electron microscopy (TEM). The effect of the used technique on the type, size and shape of the obtained structures was discussed. The fibrous mats were studied by differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), X-ray diffraction (XRD), contact angle measurements and mechanical tests as well. It was found that the decoration of fibers with ZnO resulted in increase of their thermal stability and hydrophobicity. The microbiological tests showed that the materials of design type “on” possessed strong antibacterial activity against the pathogenic microorganism Staphylococcus aureus. The results suggest that, due to their antibacterial activity, the obtained composite materials are suitable for wound dressing applications.