Analysis of Gas Diffusion-Induced Cassie to Wenzel State Transition
Abstract: We develop
one- and two-dimensional models for transient diffusion of gas between ridges into a
quiescent liquid suspended in the Cassie state above them. In the first case study of
the one-dimensional model, we assume that the liquid and gas are initially at the same
pressure and that the liquid column is sealed at the top. In the second one, we assume
that the gas initially underg... read moreoes isothermal compression and that the liquid column is
exposed to gas at the top. In the two-dimensional model, we capture the effects of
meniscus curvature and domain deformation and numerically solve the governing equations
by using a Chebyshev collocation (spectral) method. Our models provide a framework to
compute the transient gas concentration field in the liquid, the time when the triple
contact line begins to move down the ridges, and the time when menisci reach the bottom
of the substrate compromising the Cassie state. At illustrative conditions, we show the
effects of geometry, hydrostatic pressure, and initial gas concentration on the Cassie
to Wenzel state transition.
Thesis (M.S.)--Tufts University, 2018.
Submitted to the Dept. of Mechanical Engineering.
Advisor: Marc Hodes.
Committee: Erica Kemmerling, and Robert Viesca.
Keyword: Mechanical engineering.read less