Synthesis and self-assembly of graft polymers with variable grafting density

New approaches have been developed to enable facile control of grafting d., side-chain length, and total backbone d.p. These synthetic advances were achieved by living ring-opening metathesis copolymn. of a macromonomer (PLA or PS) and a discrete diluent (DME or DBE) in different feed ratios. The consequences of grafting d. variations have been studied in the context of block copolymer self-assembly. We found that systems with sym. diblock (PLA-b-DME)_n-(PS-b-DBE) bearing various grafting densities could self-assemble into lamella morphol. The lamella domain spacings, detd. by small angle X-ray scattering (SAXS) expts., reveal unusual scaling trends presumably assocd. with drastic changes in chain conformations resulting from grafting d. variations.