TY - JOUR
T1 - Dewetting transitions on superhydrophobic surfaces
T2 - When are wenzel drops reversible?
AU - Boreyko, Jonathan B.
AU - Collier, C. Patrick
PY - 2013/9/5
Y1 - 2013/9/5
N2 - On superhydrophobic surfaces, drops in the Wenzel state can be switched to the suspended Cassie state in some cases but in other cases are irreversibly impaled in the surface roughness. To date, the question of when dewetting transitions are possible for Wenzel drops has not been resolved. Here, we show that pinned Wenzel drops being stretched out-of-plane cannot reduce their contact angle below a critical value where unstable pinch-off occurs, preventing dewetting for Wenzel drops that exhibit receding contact angles beneath this critical pinch-off angle. Dewetting transitions are therefore only possible for Wenzel drops with moderately large receding contact angles (θr ≈ 90), which requires low surface roughness for one-tier surfaces or a Partial Wenzel wetting state for two-tier surfaces.
AB - On superhydrophobic surfaces, drops in the Wenzel state can be switched to the suspended Cassie state in some cases but in other cases are irreversibly impaled in the surface roughness. To date, the question of when dewetting transitions are possible for Wenzel drops has not been resolved. Here, we show that pinned Wenzel drops being stretched out-of-plane cannot reduce their contact angle below a critical value where unstable pinch-off occurs, preventing dewetting for Wenzel drops that exhibit receding contact angles beneath this critical pinch-off angle. Dewetting transitions are therefore only possible for Wenzel drops with moderately large receding contact angles (θr ≈ 90), which requires low surface roughness for one-tier surfaces or a Partial Wenzel wetting state for two-tier surfaces.
UR - http://www.scopus.com/inward/record.url?scp=84883679800&partnerID=8YFLogxK
U2 - 10.1021/jp4053083
DO - 10.1021/jp4053083
M3 - Article
AN - SCOPUS:84883679800
SN - 1932-7447
VL - 117
SP - 18084
EP - 18090
JO - Journal of Physical Chemistry C
JF - Journal of Physical Chemistry C
IS - 35
ER -