Nanophase separation and hindered glass transition in side-chain polymers

Nat Mater. 2003 Sep;2(9):595-9. doi: 10.1038/nmat966. Epub 2003 Aug 24.

Abstract

Nanophase separation on length scales of 1-5 nanometres has been reported previously for small-molecule liquids, metallic glasses and also for several semicrystalline, liquid-crystalline and amorphous polymers. Here we show that nanophase separation of incompatible main and side-chain parts is a general phenomenon in amorphous side-chain polymers with long alkyl groups. We conclude from X-ray scattering and relaxation spectroscopy data for higher poly(n-alkyl acrylates) (PnAA) and poly(n-alkyl methacrylates) (PnAMA) that alkyl groups of different monomeric units aggregate in the melt and form self-assembled alkyl nanodomains with a typical size of 0.5-2 nm. A comparison with data for other polymer series having alkyl groups reveals that important structural and dynamic aspects are main-chain independent. A polyethylene-like glass transition within the alkyl nanodomains is observed and discussed in the context of a hindered glass transition in self-assembled confinements. This is an interesting link between central questions in glass-transition research and structural aspects in nanophase-separated materials.

Publication types

  • Evaluation Study
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acrylates / chemistry*
  • Alkylation
  • Crystallization / methods*
  • Crystallography / methods*
  • Crystallography, X-Ray
  • Materials Testing / methods
  • Methacrylates / chemistry*
  • Molecular Conformation
  • Nanotechnology / methods*
  • Polyethylene / chemistry
  • Polymers / chemistry*
  • Polymethacrylic Acids

Substances

  • Acrylates
  • Methacrylates
  • Polymers
  • Polymethacrylic Acids
  • Polyethylene