BEGIN:VCALENDAR
VERSION:2.0
PRODID:-//CERN//INDICO//EN
BEGIN:VEVENT
SUMMARY:Solvent restructuring at colloidal nanoparticle surfaces
DTSTART;VALUE=DATE-TIME:20160203T033000Z
DTEND;VALUE=DATE-TIME:20160203T034500Z
DTSTAMP;VALUE=DATE-TIME:20260419T080423Z
UID:indico-contribution-517@events01.synchrotron.org.au
DESCRIPTION:Speakers: Mirijam Zobel (Friedrich-Alexander-University Erlang
 en-Nürnberg)\nInterfaces are the key to understand manifold chemical and 
 physical processes\, for instance catalytic reactions as well as nanoparti
 cle nucleation and growth. Nanoparticle surfaces have a strong tendency to
  restructure to strained atomic arrangements in order to stabilize themsel
 ves at their finite size [1\,2]. But also restructuring of the solvent mol
 ecules takes place. The presence of colloidal nanoparticles in bulk solven
 ts induces a reorientation of the solvent molecules and a change of the hy
 drogen bond network in the vicinity of the particle surface.\nWe could for
  the first time experimentally prove the universality of solvent restructu
 ring around nanoparticles for a matrix of redispersed nanoparticles (ZnO\,
  TiO2\, ZrO2\, Ag) in the primary alcohols methanol to 1-propanol as well 
 as in nonpolar hexane and water. We carried out high-energy x-ray scatteri
 ng experiments on colloidal dispersions with a metal ion concentration of 
 ca. 0.4 wt% / 30 mM. We observe primarily the reorientation of solvent mol
 ecules along the surface normal\, yielding a sinusoidal oscillation of the
  solvent electron density profile in the corresponding pair distribution f
 unctions (PDF). The rearrangement of molecules reaches out as far as 2 nm 
 into the bulk liquid and the decays exponentially [3].\nMolecular dynamics
  modelling predict that the solvent restructuring is influenced by the par
 ticle size\, shape\, crystallinity or the facetting [4]. Nucleation and gr
 owth depend on the attachment of new primary building blocks like ions or 
 precursor clusters to existing particle surfaces. This process is determin
 ed by the interaction of the building blocks with the surface. The interac
 tion and the electric field of the nanoparticle is however modulated by th
 e solvent layering at the surface. We carried out in-situ PDF experiments 
 on the nucleation of 3 nm large ZnO nanoparticles from precursor clusters 
 in ethanol and revealed that the layering of the solvent molecules at the 
 nanoparticle surface changes during nucleation. Understanding these change
 s will help us in the future to better model nanoparticle nucleation and g
 rowth.\n\n[1] Zhang\, H.\, et al. Nature 424 (2003)\, 1025\n[2] Gilbert\, 
 B.\, et al. Science 305 (2004)\, 651\n[3] Zobel\, M.\, et al. Science 347 
 (2015)\, 292\n[4] Spagnoli\, D.\, et al. Geochimica et Cosmochimica Acta 7
 3 (2009) 4023\n[5] Silvera Batista\, C. A.\, et al. Science 350 (2015)\, 6
 257\n\nhttps://events01.synchrotron.org.au/event/19/contributions/517/
LOCATION:
URL:https://events01.synchrotron.org.au/event/19/contributions/517/
END:VEVENT
END:VCALENDAR