In this study, axisymmetric drop shape analysis-profile (ADSA-P) and atomic force microscopy (AFM) were employed to study the surface features of polypropylene (PP) and hydrosilylated polypropylene (SPP). Static and dynamic contact angles were measured using ADSA-P. Water permeability was calculated from the results of static contact angle measurements. To our knowledge, this is the first attempt to obtain permeability using ADSA-P. The water permeability and wettability of PP are greater than those of SPP. Surface free energy was calculated by the equation of state theory and other methods, and the influence of surface roughness on surface free energy was taken into consideration and incorporated into the calculation. Topographic images of the sample surfaces were obtained using AFM. Compared to PP, the SPP surface shows larger but smoother peaks. Calculated results show that SPP has a lower surface free energy than PP. The surfaces of both PP and SPP can be modeled as a homogeneous but rough surface.