Noncovalent functionalization of multi-walled carbon nanotubes with siloxane polyether copolymer

Siloxane polyether copolymer (PSPEO), a new amphiphilic macromolecule, which consists of hydrophobic –Si–O–Si– main chain and hydrophilic pendant parts of polyethylene oxide (PEO), has a comb-polymer molecular structure and exhibits excellent properties such as super-wettability and extremely low surface tension. Multi-walled carbon nanotubes (MWNTs) can be easily solubilized in water by noncovalent functionalization with PSPEO. TEM, HRTEM and Raman spectra were used to characterize the functionalized MWNTs. The results reveal that PSPEO is adsorbed on surface of MWNTs, creating a 5–10 nm adsorption layer to impede the aggregation of nanotubes. TEM measurement confirmed the single-tube nature of the MWNTs suspensions. The MWNTs/PSPEO suspensions were stable over 3 months.