Structure of solutions of polysiloxane polyblock copolymers

The structure of solutions of a ladder phenylsilsesquioxane-dimethylsiloxan e polyblock copolymer was studied by the dynamic methods and indicatrix lig ht scattering in combination with gel-permeation chromatography and inverse gas chromatography. It was shown that the structure of the block copolymer solutions is mainly determined by the thermodynamic quality of a solvent w ith respect to a rigid block. The choice of a solvent that is selective Co the flexible block leads to the formation of the thermodynamic associates o f macrochains. It was found that the associates are predominantly formed by the high- and tow-molecular-mass fractions of macrochains. The low-molecul ar-mass fraction of the block copolymer is enriched with the rigid block.