Interfacial Forces are Modified by the Growth of Surface Nanostructures
Access StatusFull text of the requested work is not available in DASH at this time ("dark deposit"). For more information on dark deposits, see our FAQ.
MetadataShow full item record
CitationNa, Chongzheng and Scot T. Martin. 2008. Interfacial forces are modified by the growth of surface nanostructures. Environmental Science and Technology 42, no. 18: 6883–6889.
AbstractNanostructures formed by chemical reaction can modify the interfacial forces present in aqueous solution near a surface. This study uses force-volume microscopy to explore this phenomenon for the growth of manganese oxide nanostructures on rhodochrosite. The interfacial forces above the oxide nanostructures are dominated by electrostatic repulsion for probe−surface separations greater than ca. 2 nm but are overtaken by van der Waals attraction for shorter distances. Across the investigated pH range 5.0−9.7, the maximum repulsive force occurs 2.4 (±1.1) nm above the oxide nanostructures. The magnitude of the repulsive force decreases from pH 5.0 to 6.5, reaches its minimum at 6.5, and then increases steadily up to pH 9.7. Specifically, fmax(pN) = 23(±4)[6.8(±2.1) pH] for pH < 6.5 and fmax(pN) = 19(±2)[pH 6.1(±1.0)] for pH ≥ 6.5. This dependence indicates that oxide nanostructures have a point of zero charge in the pH range 6−7. In comparison to the nanostructures, the rhodochrosite substrate induces only small interfacial forces in the same pH range, suggesting a neutral or weakly charged surface. The quantitative mapping of interfacial forces, along with the associated influencing factors such as pH or growth of nanostructures, provides a basis for more sophisticated and accurate modeling of processes affecting contaminant immobilization and bacterial attachment on mineral surfaces under natural conditions.
Citable link to this pagehttp://nrs.harvard.edu/urn-3:HUL.InstRepos:2958608
- FAS Scholarly Articles