Hierarchical Self-Assembly\nin Supramolecular Double-Comb\nDiblock Copolymer Complexes

Abstract

Hierarchical self-assembly of supramolecular double-comb\ndiblock\ncopolymer complexes, based on a diblock copolymer in which both blocks\ncan participate in the hydrogen bonding with short amphiphiles, is\ndiscussed. A symmetric poly­(4-vinylpyridine)-<i>b</i>-poly­(<i>N</i>,<i>N</i>-dimethylacrylamide) (P4VP-<i>b</i>-PDMA) diblock copolymer was synthesized via reversible addition–fragmentation\nchain transfer (RAFT) polymerization. Supramolecular double-comb complexes\nwere prepared by hydrogen bonding of 3-pentadecylphenol (PDP) to both\nblocks, as confirmed by infrared spectroscopy. The self-assembled\nstructures were studied using small-angle X-ray scattering (SAXS),\nwide-angle X-ray scattering, and transmission electron microscopy\n(TEM). Self-assembly of the supramolecular complex containing a stoichiometric\namount of PDP resulted in a lamellar-in-lamellar structure in which\nthe large length scale is formed by the phase separation between the\nsupramolecular blocks of the supramolecular complex. Both domains\ncontain a smaller lamellar morphology of a different short length\nscale periodicity, orientated perpendicular with respect to the large\nlength scale lamellar structure. Because of the difference in periodicity,\nthe two short length scales can be distinguished clearly in SAXS and\nTEM.