‘Chocolate Chip Cookies’

Nature often seems to use more than one length-scale of roughness – the Lotus leaf has small bumps on large bumps. Using photolithographic techniques and electrodeposition, it is possible to overlay large scale textured surfaces with small-scale roughness and see whether surfaces with multiple length scales shed water more effectively.

In one experiment a “chocolate” chip cookie pattern was created using copper. Read more about the process in the publication below.

Publication

Dual-scale roughness produces unusually water repellent surfaces
N.J. Shirtcliffe, G. McHale, M.I. Newton, G. Chabrol and C.C. Perry, Adv. Maters. 16 (21) (2004) 1929-1932

Further Reading

Wetting and wetting transitions on copper-based super-hydrophobic surfaces
N.J. Shirtcliffe, G. McHale, M.I. Newton, G. Chabrol and C.C. Perry, Langmuir 21 (3) (2005) 937-943