Single-walled carbon nanotubes (SWNTs), the nearly one-dimensional structures of rolled-up graphene sheets, exhibit chirality-dependent properties that are leveraged in the field of photovoltaics and drug delivery. To date, there have been no studies addressing the effects of SWNT electronic structure, i.e., chirality/helicity, on its environmental fate. This project systematically studies aggregation behavior of SWNTs with (6,5), (7,6), and mixed chiralities in environmentally relevant chemistries. SWNTs have been chirally separated using density gradient ultracentrifugation and are solubilized in water through carboxylation. Detailed physicochemical and electrokinetic characterizations are performed using NIR spectroscopy, X-ray photoelectron spectroscopy (XPS), Raman Spectroscopy, electron microscopy, and electrophoretic mobility measurements. Fundamental aggregation kinetics of the oxidized SWNTs is performed using time-resolved dynamic light scattering. Aggregation of SWNTs followed typical DLVO type behavior. Mixed chirality SWNTs showed higher propensity to aggregate compared to specific chirality ones. Aggregation kinetics data thus obtained provide with structure-property relations for SWNT fate in aquatic environments.

Chirality affects aggregation kinetics of single-walled carbon nanotubes

241st National Meeting (2011)

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