EFFECT OF ELECTROSTATIC INTERACTIONS ON THE ELECTROSPINNING BEHAVIOR OF CHARGED POLYMERS
Matthew T. Hunley1 and Timothy E. Long2
1Polymers Division, Materials Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, MD 20899
2Department of Chemistry, Virginia Polytechnic Institute and State University, Blacksburg, VA 24061
Electrospinning provides a rapid and versatile platform for the preparation of nanofibrous membranes from a wide variety of materials. Although the electrospinning process is well understood, charged polymers exhibit unexplained instabilities preventing electrospinning at moderate solution concentrations and viscosities. To investigate the structure-electrospinning behavior relationships of charged macromolecules, we synthesized two series of cationic polyelectrolytes: poly(dimethylamino ethyl methacrylate) (PDMAEMA)-based polyelectrolytes with varying counteranions and poly(3-alkyl-1-vinyl imidazolium bromide) (PVIM)-based polyelectrolytes with increasing alkyl chain lengths. The PDMAEMA-based polymers were prepared with four different counteranions: Cl-, BF4-, CF3SO3-, and (CF3SO2)2N-. Solution rheological and conductivity analysis investigated the solution behavior of all polyelectrolytes and allowed us to correlate solution dynamics with electrospinning behavior. The larger, charge-delocalized counteranions facilitated electrospinning at much lower polymer concentrations and viscosities. Similarly, longer alkyl chains on the PVIM-based polyelectrolytes led to stable electrospinning over a wider range of solution concentrations. These correlations allow us to better predict the electrospinning behavior of charged polymers.