Superhydrophilic modification of poly(propylene) and poly(ethylene terephthalate) films' surfaces was realized by the UV-initiated surface photografting of a N-vinyl pyrrolidone/N,N'-methylenebisacrylamide inverse microemulsion. AFM characterization of the treated films' surface revealed that it was the grafted quasi-bimodal (ca. 45 and 110 nm) particles of cross-linked poly(N-vinyl pyrrolidone) that led to superhydrophilicity of the surface. The grafted nanometer-scale particles showed little influence on the transparency of the substrate's surface, but endowed long-term stability to the superhydrophilicity. The surface morphology of the PP film grafted with a NVP/MBA inverse microemulsion via a one-step method. Quasi-bimodal particles (ca. 45 ran and 110 nm) were tethered on the film's surface, and the corresponding surface water CA fell below 5 degrees.