Dual Length Scales: Chocolate (Cu) 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.

Additional 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.