Quantitative measurement of nanoparticle halo formation around colloidal microspheres in binary mixtures.
A new colloidal stabilization mechanism, known as nanoparticle "haloing" (Tohver, V.; Smay, J. E.; Braem, A.; Braun, P. V.; Lewis, J. A. Proc. Natl. Acad. Sci. U.S.A. 2001, 98, (16), 8950-8954), has been predicted theoretically and inferred experimentally in microsphere-nanoparticle mixtures that possess high charge and size asymmetry. The term "halo" implies the existence of a nonzero separation distance between the highly charged nanoparticles and the negligibly charged microspheres that they surround. By means of ultrasmall-angle X-ray scattering, we have quantified the microsphere-nanoparticle separation distance as well as the number of nanoparticles and their lateral separation distance within the self-organized halos that form in these binary mixtures.
Advanced Photon Source, Argonne National Laboratory, Argonne, IL 60439, USA.
Fan
F
Zhang
Gabrielle G
GG
Long
Pete R
PR
Jemian
Jan
J
Ilavsky
Valeria T
VT
Milam
Jennifer A
JA
Lewis