NEW STRUCTURAL MOTIF IN HEXAGONALLY ORDERED CYLINDRICAL TERNARY (ABC)BLOCK-COPOLYMER MICRODOMAINS

The morphologies of a yrene-block-polybutadiene-block-poly(methacrylat e) triblock copolymer (SBM) with polybutadiene as the majority compone nt as they are cast from different; solvents and solvent mixtures are determined using transmission electron microscopy (TEM) and small-angl e X-ray scattering (SAXS) techniques. Besides a lamellar morphology an d microphase separated structures of poor long-range order, a morpholo gy is identified in which both A (polystyrene, PS) and C (poly(methyl methacrylate), PMMA) chains form separate cylindrical microdomains. In contrast to the square (p4mm) symmetry for the cylinder arrangement w hich has been discussed in the case of ABC triblock copolymers with B being the matrix forming component, we now report the formation of a n ew morphological motif of hexagonal (p6mm) symmetry, where A and C for m two kinds of cylindrical microdomains in a B matrix.