| 摘要 |
A durable hydrophobic or oleophobic surface is formed on a substrate (1) comprising a porous reservoir layer (2) containing the repellant and a porous or permeable cover layer (3). The surface of the cover layer (3) has a topography such that the integral of the function S between the limits log(f 1/mu m ->1) = -3 and log(f 2/mu m ->1) = 3 is at least 0.3 where S(log f) = a(f) X f, f being the frequency of Fourier components of amplitude a(f). The pores in the cover layer (3) are of cylindrical or conical form and produced by ablation with an ultra-violet laser. Preferred Features: The cover layer is 0.1 to 10 mu m thick, the pore size is 2 X 10 ->1 mu m 2> 2 X 10 3> mu m 2>, and the number of pores per unit surface is 0.5 mm ->2 to 10 ->2 mm ->2. The reservoir layer (2) holds 0.1 vol% to 5 vol% of the repellant. |
