Figure 1.

Video frames of the Taylor cone (left; from Movies S1, S2, and S3) together with corresponding representative SEM images (right) showing the morphology of fibers electrospun from a solution of 12.5 mass-% PVP in anhydrous ethanol in environments with low, 27% (a), and high, >50% (b–d), RH. A stable, non pulsing, and axisymmetric Taylor cone for each set of fibers produced up to RH = 65% has the following half-angles (a) 41.1, (b) 39.5, and (c) 33.9°. (The brightness and contrast of the Taylor cone images were slightly enhanced to provide better visibility of the cone profiles.)