Fibrillar constructs from multilevel hierarchical self-assembly of discotic and calamitic supramolecular motifs

We here report on polymeric solid-state self-assembly leading to organization over six length scales, ranging from the molecular scale up to the macroscopic length scale. We combine several concepts, i.e., rod-like helical and disc-like liquid crystallinity, block copolymer self-assembly, DNA-like interactions to form an ionic polypeptide-nucleotide complex and packing frustration to construct mesoscale fibrils. Ionic complexation of anionic deoxyguanosine monophosphate (dGMP) and triblock coil-rod-coil copolypeptides is used with cationic end blocks and a helical rod-like midblock. The guanines undergo Hoogsteen pairing to form supramolecular discs, they 7-stack into columns that self-assemble into hexagonal arrays that are controlled by the end blocks. Packing frustration between the helical rods from the block copolymer midblock and the discotic motif limits the lateral growth of the assembly thus affording mesoscale fibrils, which in turn, form an open fibrillar network. The concepts suggest new rational methodologies to construct structures on multiple length scales in order to tune polymer properties.