Reversible switching between superhydrophobic states on a hierarchically structured surface.
Nature offers exciting examples for functional wetting properties based on superhydrophobicity, such as the self-cleaning surfaces on plant leaves and trapped air on immersed insect surfaces allowing underwater breathing. They inspire biomimetic approaches in science and technology. Superhydrophobicity relies on the Cassie wetting state where air is trapped within the surface topography. Pressure can trigger an irreversible transition from the Cassie state to the Wenzel state with no trapped air--this transition is usually detrimental for nonwetting functionality and is to be avoided. Here we present a new type of reversible, localized and instantaneous transition between two Cassie wetting states, enabled by two-level (dual-scale) topography of a superhydrophobic surface, that allows writing, erasing, rewriting and storing of optically displayed information in plastrons related to different length scales.
Department of Applied Physics, Aalto University former Helsinki University of Technology, PO Box 15100, FI-00076 Aalto, Espoo, Finland.
Tuukka
T
Verho
Juuso T
JT
Korhonen
Lauri
L
Sainiemi
Ville
V
Jokinen
Chris
C
Bower
Kristian
K
Franze
Sami
S
Franssila
Piers
P
Andrew
Olli
O
Ikkala
Robin H A
RH
Ras