Phase transformations in binary colloidal monolayers.
Abstract
Phase transformations can be difficult to characterize at the microscopic level due
to the inability to directly observe individual atomic motions. Model colloidal systems,
by contrast, permit the direct observation of individual particle dynamics and of
collective rearrangements, which allows for real-space characterization of phase transitions.
Here, we study a quasi-two-dimensional, binary colloidal alloy that exhibits liquid-solid
and solid-solid phase transitions, focusing on the kinetics of a diffusionless transformation
between two crystal phases. Experiments are conducted on a monolayer of magnetic and
nonmagnetic spheres suspended in a thin layer of ferrofluid and exposed to a tunable
magnetic field. A theoretical model of hard spheres with point dipoles at their centers
is used to guide the choice of experimental parameters and characterize the underlying
materials physics. When the applied field is normal to the fluid layer, a checkerboard
crystal forms; when the angle between the field and the normal is sufficiently large,
a striped crystal assembles. As the field is slowly tilted away from the normal, we
find that the transformation pathway between the two phases depends strongly on crystal
orientation, field strength, and degree of confinement of the monolayer. In some cases,
the pathway occurs by smooth magnetostrictive shear, while in others it involves the
sudden formation of martensitic plates.
Type
Journal articlePermalink
https://hdl.handle.net/10161/12618Published Version (Please cite this version)
10.1039/c5sm00009bPublication Info
Yang, Ye; Fu, Lin; Marcoux, Catherine; Socolar, Joshua ES; Charbonneau, Patrick; &
Yellen, Benjamin B (2015). Phase transformations in binary colloidal monolayers. Soft Matter, 11(12). pp. 2404-2415. 10.1039/c5sm00009b. Retrieved from https://hdl.handle.net/10161/12618.This is constructed from limited available data and may be imprecise. To cite this
article, please review & use the official citation provided by the journal.
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Show full item recordScholars@Duke
Patrick Charbonneau
Professor of Chemistry
Professor Charbonneau studies soft matter. His work combines theory and simulation
to understand the glass problem, protein crystallization, microphase formation, and colloidal
assembly in external fields.
Joshua Socolar
Professor of Physics
Prof. Socolar is interested in collective behavior in condensed matter and dynamical
systems. His current research interests include:
Limit-periodic structures, quasicrystals, packing problems, and tiling theory;
Self-assembly and phases of designed colloidal particles;
Organization and dynamics of complex networks;
Topological elasticity of mechanical lattices.
Benjamin Yellen
Associate Professor in the Department of Mechanical Engineering and Materials Science
Yellen's group is interested in developing highly parallel mechanisms for controlling
the transport and assembly of ensembles of objects ranging from micron-sized colloidal
particles to single cells. As of 2013, Professor Yellen is active in two main areas
of research:1) Development of single cell analysis tools using magnetic circuits.
The goal of this project is to develop an automated single cell analysis platform
that allows for highly flexible and highly paralle
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