Polymer structure and antimicrobial activity of polyvinylpyrrolidone-based iodine nanofibers prepared with high-speed rotary spinning technique.

Poly(vinylpyrrolidone)/poly(vinylpyrrolidone-vinylacetate)/iodine nanofibers of different polymer ratios were successfully prepared by a high-speed rotary spinning technique. The obtained fiber mats were subjected to detailed morphological analysis using an optical and scanning electron microscope (SEM), while the supramolecular structure of the samples was analyzed by positron annihilation lifetime spectroscopy (PALS). The maximum dissolved iodine of the fiber samples was determined, and microbiological assay was carried out to test their effect on the bacterial growth. SEM images showed that the polymer fibers were linear, homogenous, and contained no beads. The PALS results, both the o-positronium (o-Ps) lifetime values and distributions, revealed the changes of the free volume holes of fibers as a function of their composition and the presence of iodine. The micro- and macrostructural characterisation of polymer fiber mats enabled the selection of the required composition from the point of their applicability as a wound dressing.