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B. Gilbert, F. Huang, H. Zhang, and J. F. Banfield Department of Earth and Planetary Science, University of California at Berkeley, Berkeley, CA 94720 USA
The structure of nanoparticles, and surface structure in particular, can
respond dynamically to surface environment changes at room temperature.
Uncoated 3 nm ZnS nanoparticles undergo reversible structural change associated
with methanol desorption and rewetting. Water addition causes a profound,
non-reversible rearrangement to a more crystalline structure. Unexpected
differences (relative to bulk ZnS) in the structural dynamics of ZnS
nanoparticles capped with an organic ligand can be linked to the observation of
surface reconstruction. Hence, solvent or ligand interactions can alter the
structure, and potentially the reactivity of small nanoparticles at the
interface with their environment. We combine vibrational and electronic
spectroscopies with molecular dynamics modelling to investigate the structure
of the nanoparticle surface, and nature of surface chemical interactions. We
seek to determine how surface molecules, e.g. water, can drive substantial
atomic reorganization, and to identify the reactive surface sites of the
nanoparticles.
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