The self-assembly of mixtures of polystyrene-block-poly(2-vinylpyridine) (PS-P2VP) linear diblock and triblock copolymers with varying block lengths and star block copolymers with different numbers of constituent arms and compositions were investigated in a selective (toluene) and non-selective (THF) solvent by dynamic and static light scattering (DLS and SLS). In addition, solution structures formed by blending binary mixtures of complex block copolymer were investigated by cryogenic transmission electron microscopy (cryo-TEM). It is found that the single component block copolymers in THF adopt a random coil conformation having a hydrodynamic radius, Rh, of approximately 10 nm. In toluene, bimodal distributions consisting of unimers and spherical micelles formed according to the closed association model are observed. The Rh of the spherical micelles in solution depends on the degree-of-polymerization of the solvophobic block, the architecture of the parent chain and, specifically for the star block copolymers, the steric crowding between the arms. Cryo-TEM images of the mixtures created by blending from a non-selective good solvent establish the presence of particle-like and wormlike structures in solution. Certain cases lead to inspiring structures: for example,intramicellar microphase separation in a blend created from a triblock and an 8-arm star block copolymer produces hierarchical structures, such as a �brain coral-like� ensemble shown in the Figure. Figure 1. <img src='https://acs-archive-assets2.s3.amazonaws.com/239nm/uploads/9413_graphic1.jpg' alt='' />

Solution properties of self-assembled mixtures of complex block copolymers from a blended state

246th National Meeting (2013)

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