Nanometer-resolved collective micromeniscus oscillations through optical diffraction.
We study the dynamics of periodic arrays of micrometer-sized liquid-gas menisci formed at superhydrophobic surfaces immersed into water. By measuring the intensity of optical diffraction peaks in real time, we are able to resolve nanometer-scale oscillations of the menisci with submicrosecond time resolution. Upon driving the system with an ultrasound field at variable frequency, we observe a pronounced resonance at a few hundred kilohertz, depending on the exact geometry. By modeling the system using the unsteady Stokes equation, we find that this low resonance frequency is caused by a collective mode of the acoustically coupled oscillating menisci.
Rathgen
Helmut
H
Physics of Complex Fluids, University of Twente, The Netherlands. helmut.rathgen@web.de
Sugiyama
Kazuyasu
K
Ohl
Claus-Dieter
CD
Lohse
Detlef
D
Mugele
Frieder
F