Surface Enhanced Raman Spectroscopy on Carbon Filaments

Meyer, Norbert; Nestler, Klaus; Engisch, Lutz; Heilmann, Andreas; Marx, G.

doi:10.1007/s006040070116

Cited by 3 publications

(1 citation statement)

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“…Raman spectra obtained from nanoparticles prepared on silicon wafers showed two small peaks at around 1350 cm −1 and 1580 cm −1 (SI Figure S5A) in addition to the characteristic peaks for bare silicon wafers (SI Figure S5B). These bands corresponds to D and G oscillations characteristic of carbon 53 and are known to represent carbonaceous materials like graphite, soot, and carbon nanotubes. 54,55 Hence, the results indicate the presence of carbon on the nanoparticle surface, which may be a byproduct of CVD synthesis.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

Sorption of Silver Nanoparticles to Environmental and Model Surfaces

Abraham

Barnikol

Baumann

et al. 2013

Environ. Sci. Technol.

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The fate of engineered nanoparticles in environmental systems is controlled by changes in colloidal stability and their interaction with different environmental surfaces. Little is known about nanoparticle-surface interactions on the basis of sorption isotherms under quasi-equilibrium conditions, although sorption isotherms are a valuable means of studying sorbate-sorbent interactions. We tested the extent to which the sorption of engineered silver nanoparticles (nAg) from stable and unstable suspensions to model (sorbents with specific chemical functional groups) and environmental (plant leaves and sand) surfaces can be described by classical sorption isotherms. Atomic force microscopy (AFM) and scanning electron microscopy (SEM) qualitative and quantitative analyses were also used to assess the morphology and nanomechanical parameters of the covered surfaces. The sorption of nAg from stable suspensions was nonlinear and best described by the Langmuir isotherm. Langmuir coefficients varied with sorbent surface chemistry. For nAg sorption from an unstable suspension, the sorption isotherms did not follow any classical sorption models, suggesting interplay between aggregation and sorption. The validity of the Langmuir isotherm suggests monolayer sorption, which can be explained by the blocking effect due to electrostatic repulsion of individual nanoparticles. In unstable suspensions, aggregates are instead formed in suspension and then sorbed, formed on the surface itself, or formed in both ways.

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Section: ■ Results and Discussionmentioning

confidence: 99%