Influence of ionic conductivity on unconfined melt electrospinning of thermoplastics*

Ionic additives incorporated into thermoplastics melts can influence both viscoelastic properties and ionic conductivity. Such effects can be used to manipulate the process of melt electrospinning. In particular, fiber diameter is impacted by the melt viscosity as well as ionic motion within the melt under the influence of an applied electric field. Decreased fiber diameter could open pathways for fabrication of high strength mesoscale thermoplastic nanofibers, which have significant importance for filtration and biological applications. My talk will focus on how altered melt ionic conductivity due to commercial additives affects an unconfined melt electrospinning process. I will report ionic conductivity measurements obtained using broad-band impedance spectroscopy for two different grades of commercial linear low-density polyethylene with varying viscosities as a function of melt temperature and additive concentration. Corresponding viscosity measurements were performed by means of rotational plate rheometry. The rate of jet formation, the number of jets in steady-state, and the resulting fiber diameters were determined to characterize the effects of additive-doping of melts on the unconfined melt electrospinning process.