Covalent functionalization of multi-walled carbon nanotube surfaces by conjugated polyfluorenes

The outer surface of multi-walled carbon nanotubes (MWCNTs) was successfully modified with 7-bromo-9,9-dioctylfluorene-2-carbaldehyde by using 1,3-dipolar cycloaddition of azomethine reaction to introduce bromo functional groups. The peripheral bromo functional groups can be used to further react with AB-type monomers through Suzuki polycondensation to afford the PF-functionalized MWCNTs, which are of a cable-like structure. Through covalent connection to MWCNTs, the fluorescence of polyfluorenes was completely quenched by the MWCNTs, indicating a fast photo-induced electron transfer from polyfluorenes to MWCNTs.