Dispersion of carbon nanotubes using end-functionzalized polymers

Abstract

Carbon nanotubes have various attractive properties such as high mechanical property, high thermal stability and tunable electrical conductivity, etc. However the pristine carbon nanotubes are generally insoluble in organic solvents or polymer matrix due to the strong Van der Waals interaction among them. In order to utilize the superior properties of idealized one dimensional structure, developing a robust strategy to promote the dispersion is crucial. In this thesis, a new dispersion method for carbon nanotubes using end functionalized polymer is introduced. End functional groups such as amine and carboxyl groups, attached to polystyrene can form hydrogen bonding with carboxyl groups at the surfaces of multi-walled carbon nanotubes. The noncovalent functionalization promotes the dispersion of carbon nanotubes in organic solvent and polymer matrix. This novel method for dispersion does not require any complicated chemistry or multi-step process and is expected to be universally applicable to a broad range of polymers and organic solvents. The carbon nanotube / polymer nanocomposites using end-functinalized polystyrene as a matrix polymer showed both better electrical conductivity and mechanical property than those of non-functionzalized polystyrene.