ROXANA DELIU, IOAN GABRIEL SANDU, ROMEN BUTNARU, DAVID LUKAS, ION SANDU NEEDLELESS ELECTROSPINNING RELAXATION TIME OF THE AQUEOUS SOLUTIONS OF POLY (VINYL ALCOHOL) Relaxation time reflects dynamic phenomena in the early stages of electrospinning after an abrupt application of an external electric field. Experimental counterpart of relaxation times, i.e., characteristic hydrodynamic times, have been measured using a laboratory device designed especially for this kind of experiments. The experiments supporting the hypothesis are carried out with aqueous solutions of poly (vinyl alcohol) of various concentrations. Experimental data are compared with theoretical predictions of relaxation times aiming to a deeper analysis of dynamic phenomena during the earliest stages of electrospinning. Qualitative and quantitative comparison of theoretical and experimental relaxation times determined that characteristic hydrodynamic times are encouraging. Moreover, the experimental apparatus for characteristic hydrodynamic time investigation revealed regular discharges in a spinning zone of the electro-spinner that imminently precede electrospinning jet appearance. Results of the work contribute to a deeper understanding of a spin-ability of polymeric solutions using electrospinning and are an inspiration for new electrospinning variants.
Keywords: nanofibers, needleless electrospinning on the rod, polyvinyl alcohol aqueous solutions, rod, relaxation time