The environmental fate of nanoparticles is influenced by organic ligands bound to their surfaces. Differences in ligand-nanoparticle binding motifs can confound investigation of the influence of organic ligand properties on nanoparticle fate. We therefore developed a strategy to modularly functionalize metal oxide nanoparticles using a citric acid derivative bearing an alkyne group. This ligand forms stable, multi-dentate complexes to metal oxide nanoparticles and enables subsequent functionalization via the Cu(I)-catalyzed azide-alkyne cycloaddition reaction. We demonstrated the broad utility of this strategy by functionalizing metal oxide nanoparticulate films. For environmental fate studies, we functionalized colloidally suspended TiO2 nanoparticles with poly(ethylene glycol) ligands bearing neutral, cationic, and anionic head groups. We investigated nanoparticle aggregation by dynamic light scattering and nanoparticle attachment to humic substances by QCM-D. This strategy enables the effects of varying nanoparticle surface functionalization on environmental fate processes to be understood without the confounding influence of differing surface-binding motifs.

Modular surface functionalization of metal oxide nanoparticles toward the study of their environmental fate and transport

243rd National Meeting (2012)

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