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Conformations and Effective Interactions of Polymer-Coated Nanoparticles at Liquid Interfaces
journal contribution
posted on 2014-10-28, 00:00 authored by Konrad Schwenke, Lucio Isa, David L. Cheung, Emanuela Del GadoWe investigate conformations and
effective interactions of polymer-coated
nanoparticles adsorbed at a model liquid–liquid interface via
molecular dynamics simulations. The polymer shells strongly deform
at the interface, with the shape governed by a balance between maximizing
the decrease in interfacial area between the two solvent components,
minimizing unfavorable contact between polymer and solvent, and maximizing
the conformational entropy of the polymers. Using potential of mean
force calculations, we compute the effective interaction between the
nanoparticles at the liquid–liquid interface. We find that
it differs quantitatively from the bulk and is significantly affected
by the length of the polymer chains and by the solvent quality. Under
good solvent conditions, the effective interactions are always repulsive
and soft for long chains. The repulsion range decreases as the solvent
quality decreases. In particular, under poor solvent conditions, short
chains may fail to induce steric repulsion, leading to a net attraction
between the nanoparticles, whereas with long-enough chains the effective
interaction potential may feature an additional repulsive shoulder
at intermediate distances.