Synthesis and morphology of molecular brushes with polyacrylonitrile block copolymer side chains and their conversion into nanostructured carbons

Densely grafted brushes with polyacrylonitrile (PAN) di- (AB) and triblock (ABC) copolymer side chains were synthesized first time by ATRP using the grafting from technique. Tapping-mode atomic force microscopy showed that these brushes displayed wormlike shapes on mica surface. A necklacelike structure was observed for brushes with poly(n-butyl acrylate)-b-polyacrylonitrile-b-poly(tert-butyl acrylate) triblock copolymer side chains. After conversion of poly(tert-butyl acrylate) side chains to poly(acrylic acid), they were cross-linked with diamine to fix the extended 3-dimensional structure. Such shell-cross-linked molecular brushes showed improved stability during transferring from solution to flat substrates and have been successfully converted into nanostructured carbons through pyrolysis. The pyrolyzed materials exhibited characteristics of partially graphitic carbon.