Figure 4

AFM 2D and 3D images of the membranes: (a, b) for untreated membrane; (c, d) for N₂ plasma-treated membranes and (e, f) for Ar plasma-treated membranes (7 min exposure time); (g, h) for N₂ plasma-treated membranes, and (i, j) for Ar plasma-treated membranes (12 min exposure time).