(551b) pH-Responsive Copolymer Functionalized Single Wall Carbon Nanotubes for Switchable Aqueous Dispersibility

Carbon nanotubes have been extensively studied for over a decade because of their unique mechanical, electrical, optical and thermal properties. However, in order to make carbon nanotubes useful in biomedical or biotechnologies applications, the materials must be modified first to improve aqueous dispersibility. The ultimate fate of dispersible nanomaterials, however, is a subject of great environmental concern. In this work, we aim to create carbon nanotubes with switchable dispersibility through the use of grafted pH-responsive polymer chains.

In this work, we successfully used an ultraviolet light initiated ?graft from? polymerization method to fabricate polymer functionalized single wall carbon nanotubes with pendant pH-responsive polymer chains. The copolymer formed from poly (methacrylic acid) (PMMA) and polyethylene glycol methyl ether methacrylate (PEGMA) monomers is welled established for its pH-responsive swelling/deswelling behavior of the copolymer was utilized to control the carbon nanotube aqueous dispersibility. The morphology of the carbon nanotubes was characterized by SEM before and after functionalization. Dynamic light scattering was employed to observe the swelling/collapsing behavior of the grafted chains. In addition, covalent bonding of the copolymer to the carbon nanotubes was studied with Raman, FT-IR, and XPS spectroscopic techniques.