Roughness-induced hydrophobicity is an area of rapid growth which can be achieved through surface texture or surface porosity. Characterizing the effect of surface roughness on wetting behavior of surfaces with irregular shapes has always been a challenging problem. In this work, changing the environmental conditions during electrospinning of hydrophilic cellulose acetate solutions produced highly porous ribbon like fibers, differed widely in their surface morphologies. All samples showed apparent hydrophobicity with water contact angles between 121 degrees and 146 degrees. The specific surface area was introduced for the first time, as a comprehensive parameter to predict contact angles of noncircular fibers. Statistical modeling revealed that the log-linear models would better fit the data in comparison with the other linear forms. These results confirmed that the specific surface area could be an appropriate single variable for predicting the contact angles of multiscale porous and wrinkled structures of electrospun fibers. Moreover, the membrane produced at 20 degrees C temperature and the relative humidity of 60% revealed surprisingly high specific surface area (276.63 m(2)/g) that seems very promising for industrial applications such as separation technologies. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2018, 56, 1012-1020