Morphology of electrospun nylon-6 nanofibers as a function of molecular weight and processing parameters

In the present study, the morphology and mechanical properties of nylon-6 nanofibers were investigated as a function of molecular weight (30,000, 50,000, and 63,000 g/mol) and electrospinning process conditions (solution concentration, voltage, tip-to-collector distance, and flow rate). Scanning electron micrographs (SEM) of nylon-6 nanofibers showed that the diameter of the electrospun fiber increased with increasing molecular weight and solution concentration. An increase in molecular weight increases the density of chain entanglements (in solution) at the same polymer concentration; hence, the minimum concentration to produce nanofibers was lower for the highest molecular weight nylon-6. The morphology of electrospun fibers also depended on tip-to-collector distance and applied voltage concentration of polymer solution as observed from the SEM images. Trends in fiber diameter and diameter distribution are discussed for each processing variable. Mechanical properties of electrospun nonwoven mats showed an increase in tensile strength and modulus as a function of increasing molecular weight. (c) 2007 Wiley Periodicals, Inc.