Adsorption of silica colloids onto like-charged silica surfaces of different roughness
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Particle adsorption was explored in a model optical polishing system, consisting of silica colloids and like-charged silica surfaces. The adsorption was monitored in situ under various suspension conditions, in the absence of surfactants or organic modifiers, using a quartz crystal microbalance with dissipation monitoring (QCM-D). Changes in surface coverage with particle concentration, particle size, pH, ionic strength and ionic composition were quantified by QCM-D and further characterized ex situ by atomic force microscopy (AFM). A Monte Carlo model was used to describe the kinetics of particle deposition and provide insights on scaling with particle concentration. Transitions from near-zero adsorption to measurable adsorption were compared with equilibrium predictions made using the Deraguin-Verwey-Landau-Overbeek (DLVO) theory. In addition, the impact of silica surface roughness on the propensity for particle adsorption was studied on various spatial scale lengths by intentionally roughening the QCM sensor surface using polishing methods. It was found that a change in silica surface roughness at the AFM scale from 1.3 nm root-mean-square (rms) to 2.7 nm rms resulted in an increase in silica particle adsorption of 3-fold for 50-nm diameter particles and 1.3-fold for 100-nm diameter particles—far exceeding adsorption observed by altering suspension conditions alone, potentially because roughness at the proper scale reduces the total separation distance between particle and surface.
- Research Organization:
- Lawrence Livermore National Laboratory (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC52-07NA27344; LLNL-JRNL-707117
- OSTI ID:
- 1348992
- Alternate ID(s):
- OSTI ID: 1417107
- Report Number(s):
- LLNL-JRNL-707117
- Journal Information:
- Colloids and Surfaces. A, Physicochemical and Engineering Aspects, Vol. 520, Issue C; ISSN 0927-7757
- Publisher:
- ElsevierCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Web of Science
Influence of partial charge on the material removal rate during chemical polishing
|
journal | September 2018 |
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