Composite material with a superhydrophobic surface and coating composition for superhydrophobic post-treatment of microstructured surfaces

Abstract

A composite material with a superhydrophobic surface comprising a first-level surface structure with elevations and / or depressions having at least one spatial dimension Δdmicro in the range of from 1 × 10-3 m to 1 × 10-6 m and a second-level surface layer covering the first-level surface structure and comprising aggregates of hydrophobic nanoparticles and at least partially crosslinked hydrophobic polymers, wherein the mass ratio of the total amount of hydrophobic nanoparticles to the total amount of at least partially crosslinked hydrophobic polymers is in the range of from 1:5 to 5:1, the average thickness of the second-level surface layer dnano is in the range of from 25 nm to 5000 nm, the second-level surface layer has elevations having at least one spatial dimension Δdnano in the range of from 5 nm to 1000 nm, the fluorine content is less than 1% by weight, and wherein the ratio of at least one of the at least one spatial dimension Δdmicro to the average thickness of the second-level surface layer dnano is at least 5:1.