Synthesis of hydrophobic and hydrophilic graphitic carbon nanofiber polymer brushes

Herringbone graphitic carbon nanofiber (GCNF)-polymer brushes are prepared by atom transfer radical polymerization (ATRP) using the "grafted-from" synthesis strategy. Polymerization of acrylate esters occurs at surface sites covalently derivatized with ATRP initiators to form GCNF-poly(n-butyl acrylate), GCNF-poly(isobutyl methacrylate), and GCNF-poly(tert-butyl acrylate) polymer brushes. Acid hydrolysis of the GCNF-poly(tert-butyl acrylate) polymer brush gives a GCNF-poly(acrylic acid) polymer brush. Solution dispersibilities of GCNF-polymer brushes are controlled by the solubility properties of the polymer brush component, with GCNF-poly(acrylate ester) brushes being hydrophobic, whereas the GCNF-poly(acrylic acid) brush is hydrophilic. Because of the unique atomic structure of GCNFs, a high surface density (ca. 3 chains/10 nm(2) of GCNF surface) of polymer brush functionalization is realized.