Abstract
Self-assembly of diblock copolymer can generate a series of microdomains packed in long range ordered lattices (1-D stacked lamellae, hexagonally packed cylinders, gyroid, and body-center-cubic packed sphere). In the case of cylindrical microdomains, hexgonal lattice is the only structure observed thus far, since this packing symmetry has the highest efficiency for space filling for cylindrical micelles with hard coronas. In the present study we reveal tetragonally packed cylinders in a supramolecular comb-coil block copolymer formed by the complexation of an amphiphilic surfactant, dodecylbenzene sulfonic acid (DBSA), with the poly(4-vinylpyridine) (P4VP) blocks in a symmetric PS-b-P4VP. Over the binding fractions investigated (x = 0.25 to 1.0), the system exhibited structure-within-structure morphology. When x ≥ 0.4, we found the larger-scale PS cylindrical microdomains embedding in the matrix consisting of the smaller-scale lamellar mesophase organized by the P4VP(DBSA) comb blocks. The PS cylinders were found to organize in the typical hexagonal lattice at x ≥ 0.75. Interestingly, the packing symmetry transformed into a square or tetragonal lattice when x = 0.5 and 0.6. So we use large amplitude oscillatory shear (LAOS) to create macroscopic aligned and probe the relative orientation between the smaller-scale lamellae and the larger-scale PS cylinders by 2-D SAXS pattern along different orientations to infer the reason of tetragonally packed cylinder.