(684f) Aggregation Kinetics of Carbon Nanotubes In the Presence of Biomacromolecules

Carbon nanotubes (CNTs) have a widespread potential for application due to their unique physicochemical properties. There has been lack of studies aimed at understanding the aggregation behavior of CNTs in the presence of macromolecules of environmental and biomedical relevance. A systematic study of CNT aggregation kinetics is essential in order to predict their fate and interaction in environmental and biological systems. Effects of macromolecules such as natural organic matter, polysaccharides, proteins, and lipids on the aggregation kinetics of single-walled and multi-walled carbon nanotubes (SWNTs and MWNTs) were evaluated in this study. CNTs were characterized using Raman scattering (for state of defect), thermo gravimetric analysis (for metal impurities), transmission electron microscopy (for length and diameter distribution), Fourier transformed infrared spectroscopy (for functional groups), and electrophoretic mobility (for surface charge). The aggregation kinetics of CNTs were slowed down considerably in the presence of the macromolecules. Calcium ions showed specific interaction with alginate (polysaccharide) and resulted in enhanced aggregation. Steric repulsion is proposed to be the mechanism of enhanced stability in presence of the macromolecules.