Electrospun Poly(Styrene-block-dimethylsiloxane) Block Copolymer Fibers Exhibiting Superhydrophobicity
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° and contact angle hysteresis of 15°. 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.