Figure 1.

Fiber analysis: electrospun nitrocellulose. SEM images reveal that nitrocellulose forms fibers over a narrow range of electrospinning conditions. Samples electrospun from less than 110 mg/ml underwent electrospraying, a process that occurs when polymer chain entanglements are inadequate to induce fiber formation. Fibers were evident in samples prepared from 110 mg/ml, 120 mg/ml and 140 mg/ml. Note nearly uniform fiber diameters in 110 mg/ml samples, heterogeneity of diameters present in 120 mg/ml samples and solvent defects in 140 mg/ml samples (upper left of image). Fibers in 110 mg/ml solutions were smaller than fibers produced from the 120 and 140 mg/ml starting concentrations (P < 0.05). Fibers from the 120 and 140 mg solutions were not statistically different. Note the interconnected nature of the pores in samples containing fibers. Bar = 5 μm.