Till sidans topp

Sidansvarig: Webbredaktion
Sidan uppdaterades: 2012-09-11 15:12

Tipsa en vän
Utskriftsversion

Nonlinear Concentration D… - Göteborgs universitet Till startsida
Webbkarta
Till innehåll Läs mer om hur kakor används på gu.se

Nonlinear Concentration Dependence of the Collective Diffusion Coefficient of TiO2 Nanoparticle Dispersions

Artikel i vetenskaplig tidskrift
Författare Jenny Perez-Holmberg
Zareen Abbas
Elisabet Ahlberg
Martin Hassellöv
Johan Bergenholtz
Publicerad i Journal of Physical Chemistry C
Volym 115
Nummer/häfte 28
Sidor 13609-13616
ISSN 1932-7447
Publiceringsår 2011
Publicerad vid Institutionen för kemi
Sidor 13609-13616
Språk en
Länkar dx.doi.org/10.1021/jp202585e
Ämneskategorier Kemi

Sammanfattning

Aqueous dispersions of titania nanoparticles are shown to yield collective diffusion coefficients in dynamic light-scattering measurements that depend nonlinearly on particle concentration under dilute conditions. From theory, one expects a linear dependence for monodisperse systems except for strongly interacting charged particles in low ionic strength media. Angularly resolved dynamic light-scattering measurements reveal that aggregates are present, which explains the collective diffusion coefficient tending to lower values in the dilute limit than the Stokes Einstein diffusion coefficient of the nanoparticles. A simple theoretical model based on mixtures of charged nanoparticle spheres and small amounts of larger-sized neutral or weakly charged spheres, modeling the presence of aggregates, is applied and shown to yield predictions in qualitative accord with the experimental trends. In particular, the downward curvature of the collective diffusion coefficient on diluting the system arises in the model from nanoparticles being driven into close proximity to the larger particles by electrostatic interactions. Similar experimental trends observed in silica dispersions suggest that the behavior is not an isolated finding. This study clearly shows that a small number of larger aggregates dramatically change the measured value of the collective diffusion coefficient; thus, care must be exercised when characterizing nanoparticles with dynamic light scattering.

Sidansvarig: Webbredaktion|Sidan uppdaterades: 2012-09-11
Dela:

På Göteborgs universitet använder vi kakor (cookies) för att webbplatsen ska fungera på ett bra sätt för dig. Genom att surfa vidare godkänner du att vi använder kakor.  Vad är kakor?