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Double Hydrophilic Janus Cylinders at an Air–Water Interface
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posted on 2013-02-12, 00:00 authored by Bum Jun Park, Chang-Hyung Choi, Sung-Min Kang, Kwadwo E. Tettey, Chang-Soo Lee, Daeyeon LeeColloidal particles spontaneously attach to the interface
between
two immiscible fluids to minimize the interfacial area between the
two phases. The shape and wettability of particles have a strong influence
on their configuration and interactions at fluid–fluid interfaces.
In this study, we investigate the behavior of asymmetrically hydrophilic
Janus cylinders (or double hydrophilic Janus cylinders with two different
hydrophilic regions) trapped at an air–water interface. We
find that these double hydrophilic Janus cylinders with aspect ratios
of 0.9, 1.2, and 2.4 adopt both end-on and tilted configurations with
respect to the interface. Our numerical calculations show that the
coexistence of these configurations is a result of multiple energy
minima present in the attachment energy profile that can be represented
as a complex energy landscape. Double hydrophilic Janus cylinders
with tilted orientations induce hexapolar interface deformation, which
accounts for the pair interactions between the particles as well as
the nondeterministic assembly behaviors of these particles at the
interface.