A Study of Silica Nanoparticle Adsorption Using Optical Reflectometry and Streaming Potential Techniques

The kinetics of adsorption of monodisperse nanosized silica particles (32−190 nm diameter) on silicon wafers modified with an aminopropylsilane have been studied by optical reflectometry under stagnant-flow conditions. The adsorption of negatively charged particles on a positively charged wafer surf...

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Bibliographic Details
Published in:Langmuir 1999-04, Vol.15 (8), p.2865-2870
Main Authors: Hayes, Robert A, Böhmer, Marcel R, Fokkink, Lambertus G. J
Format: Article
Language:English
Subjects:
Chemistry
Exact sciences and technology
General and physical chemistry
General, apparatus
Surface physical chemistry
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Summary:The kinetics of adsorption of monodisperse nanosized silica particles (32−190 nm diameter) on silicon wafers modified with an aminopropylsilane have been studied by optical reflectometry under stagnant-flow conditions. The adsorption of negatively charged particles on a positively charged wafer surface is driven by electrical double layer attraction and was not found to be measurably reversible. The initial rate of particle adsorption decreases with increasing particle size while the equilibrium amount adsorbed increases with electrolyte concentration. The effect of particle adsorption on the ζ potential of similarly modified glass slides was measured using streaming potential apparatus. The coverage of particles was varied using electrolyte as indicated by the reflectometry measurements. The results suggest that displacement of the plane of shear is not localized to particle covered areas.
ISSN:0743-7463
1520-5827
DOI:10.1021/la980668f