Superhydrophobicity was first observed in nature on a lotus leaf and some other plants when their leaves would not get wet. The main reason for that phenomenon was the unique surface structure of the lotus leaf and also the presence of a low surface energy material on the surface of the leaf. In order to achieve superhydrophobic surface or coating, the surface must possess hierarchical micro and nano roughness and low surface energy at the same time. Hierarchical micro and nano scale roughness will trap air on the surface that will cause an increase in the water contact angle and low surface energy will decrease the tendency of water to bond with the surface. So almost all the methods to achieve superhydrophobicity consist of two requirements of a hierarchical surface roughness as well as presence of a low surface energy material. These surfaces have many practical applications, from industrial to biomedical applications, including water/oil separation, self-cleaning, drag reduction, antifogging, anti-bacteria, anti-fouling, anti-icing, corrosion resistance, as well as many applications in industries such as marine, oil, and gas, aerospace, biomedicine etc. Hence, superhydrophobic surfaces, which can be achieved by surface modifications and/or surface coatings, have become very interesting in the last decade. The important issues and challenges in the field of superhydrophobic surfaces is stability and robustness of the surfaces.

Block copolymer poly(styrene-b-dimethylsiloxane) fibers with submicrometer diameters in the range 150-400 nm were produced by electrospinning from solution in tetrahydrofuran and dimethylformamide. Contact angle measurements indicate that the nonwoven fibrous mats are superhydrophobic, with a contact angle of 163 degrees and contact angle hysteresis of 15 degrees . The superhydrophobicity is attributed to the combined effects of surface enrichment in siloxane as revealed by X-ray photoelectron spectroscopy and surface roughness of the electrospun mat itself. Additionally, the fibers are shown by transmission electron microscopy to exhibit microphase-separated internal structures. Calorimetric studies confirm the strong segregation between the polystyrene and poly(dimethylsiloxane) blocks.