Superhydrophobic films from raspberry-like particles

We report a robust procedure for preparing superhydrophobic hybrid films on which the advancing contact angle for water is about 1651 and the roll-off angle of a 10-mu L water droplet is 3 +/- 1 degrees. Dual-size surface roughness, which mimics the surface topology of self-cleaning plant leaves, originates from well-defined silica-based raspberry-like particles that are covalently bonded to an epoxy-based polymer matrix. The roughened surface is chemically modified with a layer of poly(dimethylsiloxane) (PDMS). The robustness and simplicity of this procedure may make widespread applications of so-prepared superhydrophobic films possible.