C₆₀ fullerene inclusions in low-molecular-weight polystyrene-poly(dimethylsiloxane) diblock copolymers

We have synthesized low-molecular-weight diblock copolymers of polystyrene-block-poly(dimethylsiloxane) with total molecular weights <12 kg/mol and PS volume fractions of ∼0.2. We have investigated the phase behavior of the PS-PDMS in its pure state and with up to 10 wt% of C₆₀ added. The C₆₀ was shown to selectively segregate into the PS phase only although its solubility limit is ∼1 wt%. Although the C₆₀ aggregates above 1 wt%, the cylindrical morphology observed in the pure copolymer bulk samples persists in the C₆₀-copolymer composites even up to 10 wt% C₆₀ loading. In thin films, the pure copolymer possesses a highly ordered morphology with grains hundreds of microns across. When C₆₀ is blended with the copolymer the high degree of order rapidly decreases due to increasing numbers of defects observed.