Production and investigation of flexible nanofibers of sPEEK/PVP loaded with RuO2 nanoparticles

Abstract

Electrospinning technique was employed to fabricate composite nanofibers/nanoparticles of sulfonated polyether ether ketone, polyvinylpyrrolidone, and ruthenium oxide (sPEEK/PVP/RuO2). The samples were synthesized with different concentrations of hydrous ruthenium chloride of 2 wt%, 5 wt%, and 10 wt%, and then annealed at a temperature of 300 �C for 4 h to form the ruthenium oxide nanoparticles. Several characterization tests were conducted to study and compare the performance of the samples. Scanning electron microscopy (SEM) demonstrated the successful fabrication of nanofibers with diameter range of 140-240 nm as well as nanoparticles with average sizes within the range of 6 nm and 9 nm. The effect of annealing and RuO2 addition was illustrated by the decrease in fibers diameter. The vibration mode and structure of the samples were studied by Fourier transform spectroscopy (FTIR) along with Raman spectroscopy that revealed the strong interaction as well as crosslinking between the polymer blend and RuO2. The annealed samples exhibit enhanced thermal stability and less crystallinity as compared to the as prepared samples according to thermal gravimetric analysis (TGA) along with differential scanning calorimetry (DSC). Impedance spectroscopy tests were conducted to study the electrical properties of the samples as a function of ruthenium oxide concentration and temperature. The results illustrated the increase in resistivity as well as the activation energy with the increase of nanoparticle concentration due to the reduction in the free SO3H groups because of the strong ionic crosslinking. These observations revealed the enhancement of nanofiber properties at low temperatures, which make them suitable for different applications including supercapacitor as well as sensor applications at low temperatures.