Effect of molecular architecture on the self-diffusion of polymers in aqueous systems: A comparison of linear, star, and dendritic poly(ethylene glycol)s

Y. J. Wang, H. Therien-Aubin, W. E. Baille, J. T. Luo, X. X. Zhu

Research output: Contribution to journalArticle

12 Scopus citations

Abstract

Star polymers with a hydrophobic cholane core and four poly(ethylene glycol) (PEG) arms, CA(EGn)4, have been synthesized by anionic polymerization. Pulsed-gradient spin-echo NMR spectroscopy was used to study the diffusion behavior of the star polymers, ranging from 1000 to 10,000g/mol, in aqueous solutions and gels of poly(vinyl alcohol) (PVA) at 23°C. The star polymers have a lower self-diffusion coefficient than linear PEGs at equivalent hydrodynamic radius. In water alone, the star polymers and their linear homologues have a similar diffusion behavior in the dilute regime, as demonstrated by the similar concentration dependence of the self-diffusion coefficients. In the semidilute regime, the star polymers tend to aggregate due to their amphiphilic properties, resulting in lower self-diffusion coefficients than those of linear PEGs. 1H NMR T1 measurements at 10-70°C revealed that the PEG arms of the star polymers are more mobile than the core, suggesting the star polymers in solution have a conformation similar to that of poly(propylene imine) dendrimers.

Original languageEnglish (US)
Pages (from-to)2345-2350
Number of pages6
JournalPolymer
Volume51
Issue number11
DOIs
StatePublished - May 2010
Externally publishedYes

Keywords

  • Diffusion
  • NMR spectroscopy
  • Star polymers

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics

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