Structural Studies of Nanophase-Separated poly(2-hydroxyethyl methacrylate)-l-polyisobutylene Amphiphilic Conetworks by Solid-State NMR and Small-Angle X-ray Scattering

Attila Domján, Gábor Erdödi, Manfred Wilhelm, Michael Neidhöfer, Katharina Landfester, Béla Iván, Hans Wolfgang Spiess

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89 Citations (Scopus)

Abstract

Bicomponent nanophase-separated poly(2-hydroxyethyl methacrylate)-linked-polyisobutylene (PHEMA-l-PIB) amphiphilic conetworks were synthesized by radical copolymerization of methacrylate-telechelic polyisobutylene (MA-PIB-MA) and different amounts of 2-(trimethylsilyloxy)ethyl methacrylate (SEMA) followed by quantitative hydrolysis of the trimethylsilyl protecting groups. The PIB content of the resulting conetworks, determined by elemental analysis and solid-state 1H NMR under fast magicangle spinning (MAS), varied between 17 and 63% w/w. Phase separation and morphology of these conetworks were investigated by DSC, small-angle X-ray scattering (SAXS), and for the first time by 1H spin diffusion solid-state NMR. Two Tg values were observed by DSC in all samples. The observed Tg values were close to the literature values of both homopolymers (110 °C for PHEMA and -67 °C for PIB), indicating a strong phase-separated morphology in these conetworks. Parameters were optimized for the 1H spin diffusion NMR experiments, and the measurements were carried out with six filtering cycles and a 10 μs delay between pulses at 90 °C. The NMR and SAXS measurements prove strong phaseseparated morphology. The sizes of the hydrophilic (PHEMA) and hydrophobic (PIB) nanodomains were determined to be in the 5-15 nm range. The spin diffusion experiments also indicate strongly separated phases without a detectable interface with mixed components. The long period of our system seems to depend weakly on the volume fraction whereas the morphology of the nanophases depends on the volume fraction.

Original languageEnglish
Pages (from-to)9107-9114
Number of pages8
JournalMacromolecules
Volume36
Issue number24
DOIs
Publication statusPublished - Dec 2 2003

ASJC Scopus subject areas

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

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