Direct measurement of fluid velocity in an electrospinning jet using particle image velocimetry

By observing the movement of small fluorescent particles in an electrospinning jet, we have directly measured the fluid velocity along the jet axis. The correlation between these direct velocity measurements and the velocity calculated from the jet radius using volume conservation indicates when evaporation is a significant factor. Measurements of the fluid properties of the solution used in the experiment allow us to construct a plot of Deborah number as a function of position along the jet. Our data also indicate transverse movement at the beginning of the fluid jet, potentially indicating the precursor to the macroscopic bending instability.