Hierarchical Self-Assembly of Symmetric Supramolecular\nDouble-Comb Diblock Copolymers: a Comb Density Study

Abstract

A double-comb\ndiblock copolymer was constructed experimentally\nusing a double supramolecular approach. Addition of 3-nonadecylphenol\n(3-NDP) amphiphiles to a symmetric, double hydrogen bond accepting\npoly­(4-vinylpyridine)-<i>block</i>-poly­(<i>N</i>-acryloylpiperidine) (P4VP-<i>b</i>-PAPI) diblock copolymer\nresulted in microphase separation on both the block copolymer and\npolymer–amphiphile level. Variation of the comb density <i>x</i> in these [P4VP-<i>b</i>-PAPI]­(3-NDP)_<i>x</i> supramolecular complexes gave rise to several unique\nhierarchical nanostructures. For high comb densities (<i>x</i> = 0.8–1.2) double perpendicular lamellae-<i>in</i>-lamellae were observed, while lowering the density to <i>x</i> = 0.5 resulted in a double parallel lamellar morphology as demonstrated\nby small-angle X-ray scattering (SAXS) and transmission electron microscopy\n(TEM). Further decreasing the concentration of 3-NDP (<i>x</i> = 0.3) caused the complex to self-assemble into cylinders-<i>in</i>-lamellae, while for <i>x</i> = 0.1 3-NDP only\nserves as a plasticizing agent. The phase transitions identified as\na function of <i>x</i> are all in excellent agreement with\nour previously performed theoretical analysis.