Figure 8
SEM pictures of fibers and their surfaces from 20% ( w / v ) PS solutions with various THF/DMF ratios. (A, B, C, D) 5:1, (E, F, G, H) 2:1, (I, J, K, L) 1:1, (M, N, O, P) 1:2, and (Q, R, S, T) 1:5, v/v. The solutions were electrospun under the lowest applied voltage. RH 60%, collecting distance 15 cm, feeding rate 1.5 ml/h, and applied voltage 5 kV.