Hierarchical structures in lamellar hydrogen bonded LC side chain diblock copolymers

Antti J. Soininen, Ioanna Tanionou, Niels Ten Brummelhuis, Helmut Schlaad, Nikolaos Hadjichristidis*, Olli Ikkala, Janne Raula, Raffaele Mezzenga, Janne Ruokolainen

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

35 Scopus citations

Abstract

We show that in a hydrogen bonded LC side chain diblock copolymer with lamellar morphology on the block copolymer level, two distinct packing mechanisms of the side chain blocks are possible depending on the amount of hydrogen bonded side chains. We mixed a hydrogen bonding mesogen, cholesteryl hemisuccinate (CholHS), with poly(1,2-butadiene)-block-poly(2-vinylpyridine) (PBd-P2VP) and poly(styrene)-block-poly(4-vinylpyridine) (PS-P4VP), in which the poly(vinylpyridine) act as host blocks, and we varied the CholHS to pyridine repeat unit ratio (x). With all x, a lamellar morphology on the block copolymer level was achieved. However, at low binding of CholHS to the host block, the CholHS side chains microphase separated into a single layer inside the poly(pyridine) lamellae resulting in a novel microphase separated structure. This includes, for example, the PS-P4VP sample with x = 0.25 and all the PBd-P2VP based samples since hydrogen bonding of CholHS to P2VP was sterically limited as revealed by infrared spectroscopy. No such limits were present in the rest of the PS-P4VP samples which showed a gradual shift from the single CholHS lamella morphology to exclusively liquid crystalline smectic layers oriented perpendicular to the block domain interfaces.

Original languageEnglish (US)
Pages (from-to)7091-7097
Number of pages7
JournalMacromolecules
Volume45
Issue number17
DOIs
StatePublished - Sep 11 2012

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Inorganic Chemistry
  • Materials Chemistry

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