Submitted to: Canadian Journal of Chemistry
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2008
Publication Date: 6/1/2008
Citation: Medeiros, E.S., Mattoso, L.H., Offeman, R.D., Wood, D.F., Orts, W.J. 2008. Effect of Relative Humidity on the Morphology of Electrospun Polymer Fibers. Canadian Journal of Chemistry. 86:590-599. Interpretive Summary: Electrospinning has been the subject of a wide number of recent studies because it is a simple and versatile technique to produce micro- and nano-structured polymer materials that can be used as filtration membranes, drug release systems, wound dressings, engineered tissues, protective clothing, sensors, and composites. It has already been established that during the production of nanoscale materials accurate control of parameters governing each electrospinning system (polymer, solvent and electrospinning variables such as relative humidity) has to be taken into account to attain reproducibility. In this work, the effect of relative humidity on the morphology of electrospun nanofibers of poly(vinyl alcohol), poly(methyl metacrylate), poly(vinyl chloride), polystyrene and poly(lactic acid) dissolved in organic solvents and deionized water was studied by scanning electronic microscopy (SEM). Determining the effects of process variables on fiber structure gives us a better understanding of electrospinning science, but, more importantly, allows us to tailor-make nanostructured nanomaterials with specific desired properties.
Technical Abstract: The effect of relative humidity on the morphology of electrospun nanofibers of poly(vinyl alcohol), poly(methyl metacrylate), poly(vinyl chloride), polystyrene, and poly(lactic acid) dissolved in solvents such as toluene and N,N-dimethylformamide, 2,2,2-trifluoroethanol and deionized water was studied by scanning electronic microscopy to investigate the factors that may contribute to pore formation. Results showed that the presence of pores depends on factors such as the type of polymers used, polymer/solvent combination, molecular weight and the size of the electrospun structure. The final morphology developed implies a competition between the dynamics of phase separation and the rate of solvent evaporation. In addition, continuous solvent evaporation and constant stretching due to the electric potential difference give rise to the final shape of porous electrospun fibers.