Table 1 Liquid-repellent properties of different surface classes^{17,20,23,33,34}

Lotus-leaf effect

~2rγϕ^1/2 or

~2rγϕ ln ϕ

1–10 μN

~2rγϕ^1/2 or

~2rγϕ ln ϕ

1–10 μN

No dependence on U,

low friction and low adhesion

Lubricated

~2rγCa^2/3

0.1–5 μN

~2rγ

>10 μN

Increases nonlinearly with U, low friction but high adhesion

Polyzwitterionic brush

~2rγCa^2/3

0.02–1 μN

~2RγCa^0.6

0.02–1 μN

Increases nonlinearly with U, very low friction and adhesion