The Investigation of the Production of Salt-Added Polyethylene Oxide/Chitosan Nanofibers

Abstract

The influence of different concentrations of salt-added polyethylene oxide (PEO) on the spinnability of chitosan (CS)/PEO + NaCl blends that could be used as a component part of filters for water treatment or nanofiber membranes as well as for medical applications was investigated in this study. The morphological properties of manufactured nanofibers were analyzed as well. It was determined that an increase of PEO concentration resulted mostly in thin and round nanofibers formed during electrospinning, but the manufacturing process became complex, because many wet fibers reached the collector while spinning. Also, it was noticed that the salt was not dissolved completely in the polymer solutions and some crystals were seen in the SEM images of manufactured fiber mats. However, the addition of salt resulted in lower viscosity and better conductivity of solution and fiber mats as well. The opposite effect was observed as the concentration of PEO was increased. The orientation of produced nanofibers as well as their diameter were analyzed with commercially available software. It was determined that the results obtained by software and microscopically are repeatable. The difference among the results of diameter calculated with software and taken by microscope varied from 0% to approximately 12%. The FTIR analyses indicated that alterations in polymer concentrations or the addition of salt did not induce any discernible changes in the chemical composition or nature of the materials under investigation. The sodium chloride present in the solutions enhanced electrical properties and increased conductivity values more than 50 times for PEO solutions and six times for CS/PEO blend solutions, compared to conductivity values of solutions without salt. To assess the thermal characteristics of the PEO/CS blend nanofibers, measurements using a differential scanning calorimeter (DSC) to determine melting (Tm) and crystallization (Tc) temperatures, as well as specific heat capacities were conducted. These parameters were derived from the analysis of endothermic and exothermic peaks observed in the DSC data. It showed that all produced nanofibers were semicrystalline.

The Incorporated Drug Affects the Properties of Hydrophilic Nanofibers

“…Additionally, small particles presumably attributed to metformin were observed on the surface of nanofibers of formulation MET and on the surface of polymer film of the same formulation. A similar observation of small particles on the surface of nanofibers was described in the literature when salt was added to the polymer (PEO) solution for electrospinning [75]. However, according to European Pharmacopoeia, both metformin and carvedilol are slightly soluble in ethanol, with metformin being less soluble than carvedilol [79,80].…”

“…The elevated electrical conductivity observed in the metformin-containing polymer solution was attributed to the addition of metformin in a salt form. The literature data show that the addition of salts in the polymer solution for electrospinning may enhance the electrical properties and increase the electrical conductivity more than 50 times for pure PEO solutions [75], which is in line with the increased electric conductivity of polymer solution for formulation MET (Table 4).…”