Nanoparticle Assembly and Transport at Liquid-Liquid Interfaces
Y. Lin,1
H. Skaff,1
T. Emrick,1*
A. D. Dinsmore,2*
T. P. Russell1*
The self-assembly of particles at fluid
interfaces, driven by the reduction in interfacial energy, is well
established. However, for nanoscopic particles, thermal fluctuations
compete with interfacial energy and give rise to a
particle-size-dependent self-assembly. Ligand-stabilized nanoparticles
assembled into three-dimensional constructs at fluid-fluid interfaces,
where the properties unique to the nanoparticles were preserved. The
small size of the nanoparticles led to a weak confinement of the
nanoparticles at the fluid interface that opens avenues to
size-selective particle assembly, two-dimensional phase behavior, and
functionalization. Fluid interfaces afford a rapid approach to
equilibrium and easy access to nanoparticles for subsequent
modification. A photoinduced transformation is described in which
nanoparticles, initially soluble only in toluene, were transported
across an interface into water and were dispersed in the water phase.
The characteristic fluorescence emission of the nanoparticles provided
a direct probe of their spatial distribution.
1 Department of Polymer Science and
Engineering,
2 Department of Physics, University of
Massachusetts, Amherst, MA 01003, USA.
*
To whom correspondence should be addressed. E-mail:
tsemrick{at}mail.pse.umass.edu (T.E.); dinsmore{at}physics.umass.edu
(A.D.D.); russell{at}mail.pse.umass.edu (T.P.R.)
