Tracer diffusion in silica inverse opals

We employed fluorescence correlation spectroscopy (FCS) to study the diffusion of small fluorescence tracers in liquid filled silica inverse opals. The inverse opals consisted of a nanoporous silica scaffold spanning a hexagonal crystal of spherical voids of 360 nm diameter connected by circular por...

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Veröffentlicht in:Langmuir : the ACS journal of surfaces and colloids. - 1992. - 26(2010), 12 vom: 15. Juni, Seite 10141-6
1. Verfasser: Cherdhirankorn, Thipphaya (VerfasserIn)
Weitere Verfasser: Retsch, Markus, Jonas, Ulrich, Butt, Hans-Juergen, Koynov, Kaloian
Format: Online-Aufsatz
Sprache:English
Veröffentlicht: 2010
Zugriff auf das übergeordnete Werk:Langmuir : the ACS journal of surfaces and colloids
Schlagworte:Journal Article
Beschreibung
Zusammenfassung:We employed fluorescence correlation spectroscopy (FCS) to study the diffusion of small fluorescence tracers in liquid filled silica inverse opals. The inverse opals consisted of a nanoporous silica scaffold spanning a hexagonal crystal of spherical voids of 360 nm diameter connected by circular pores of 70 nm diameter. The diffusion of Alexa Fluor 488 in water and of perylene-3,4,9,10-tetracarboxylic diimide (PDI) in toluene was studied. Three diffusion modes could be distinguished: (1) Free diffusion limited by the geometric constraints given by the inverse opal, where, as compared to the free solution, this diffusion is slowed down by a factor of 3-4, (2) slow diffusion inside the nanoporous matrix of the silica scaffold, and (3) diffusion limited by adsorption. On the length scale of the focus of a confocal microscope of roughly 400 nm diffusion was non-Fickian in all cases
Beschreibung:Date Completed 31.08.2010
Date Revised 10.06.2010
published: Print
Citation Status PubMed-not-MEDLINE
ISSN:1520-5827
DOI:10.1021/la1002572