Supramolecular Routes to Hierarchical Structures: Comb-Coil Diblock Copolymers Organized with Two Length Scales

J. Ruokolainen, M. Saariaho, O. Ikkala, G. ten Brinke, E.L. Thomas, M. Torkkeli, R. Serimaa

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282 Citations (Scopus)

Abstract

We show that polymeric materials characterized by two length scales are obtained if diblock copolymers are mixed with amphiphilic selective solvents, leading to self-organization which combines the “block copolymer length scale” with a much shorter “nanoscale”. In this work, the amphiphilic compound is 3-n-pentadecylphenol (PDP) which is hydrogen-bonded to the pyridine group of polystyrene-block-poly(4-vinylpyridine), i.e., PS-b-P4VP. The molecular architecture resembles comb-coil diblock copolymers A-block-(B-graft-C) but is obtained using the supramolecular assembly route. The structures were determined with a combination of transmission electron microscopy and small-angle X-ray scattering. On the block copolymer scale (300 Å range), the PS blocks are microphase-separated from the P4VP(PDP)x blocks, where x denotes the ratio between the number of phenol and pyridine groups. For PS-b-P4VP block copolymers having a spherical morphology and P4VP as the minority component, the structure of PS-b-P4VP(PDP)x changes from spherical to hexagonal and further to lamellar as a function of the amount of PDP added. For all comb-coil diblock copolymer morphologies, the P4VP(PDP)x domains are further “nanophase-separated” into lamellar structures due to microphase separation of the comb copolymer-like complex between P4VP and PDP. The morphology diagram is presented for stoichiometric conditions (x = 1), using a range of different PS-b-P4VP block copolymers.
Original languageEnglish
Pages (from-to)1152-1158
Number of pages7
JournalMacromolecules
Volume32
Issue number4
DOIs
Publication statusPublished - 1999

Keywords

  • LIQUID-CRYSTALLINE BLOCK
  • POLYELECTROLYTE-SURFACTANT COMPLEXES
  • END-FUNCTIONALIZED OLIGOMERS
  • SIDE-CHAIN
  • MORPHOLOGICAL STRUCTURE
  • TRIBLOCK COPOLYMERS
  • POLYMERIC MATERIALS
  • MESOMORPHIC STATE
  • SOLID-STATE
  • BEHAVIOR

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