Hetero diels-alder chemistry for the functionalization of single-walled carbon nanotubes with cyclopentadienyl end-capped polymer strands

Single-walled carbon nanotubes (SWCNTs) are pre-functionalized with a pyridinyl-based dithioester to undergo a hetero Diels-Alder (HDA) reaction with cyclopentadienyl end-capped poly(methyl)methacrylate (Mn = 2700 g mol-1, PDI = 1.14). Fourier transform infrared spectroscopy, thermogravimetric analysis, elemental analysis (EA), and X-ray photoelectron spectroscopy (XPS) evidence the success of the grafting process. The estimated resulting grafting density (from XPS and EA) via the HDA reaction increases by a factor of more than two (0.0774 chains·nm-2 via XPS) compared with typical values obtained via a direct cyclopentadiene driven Diels-Alder conjugation onto non-functional SWCNTs under similar conditions. Cyclopentadienyl end-capped polymer strands react at the surface of pre-functionalized single-walled carbon nanotubes with a pyridine-based dithioester through a hetero Diels-Alder reaction. Elemental analysis and X-ray photoelectron spectroscopy are employed to det ermine the grafting density.