Measurement of Chain Dimensions in Dilute Polymer Solutions. A Light Scattering and Viscometric Study of Linear Polyisoprene in Cyclohexane

N. S. Davidson*, L. J. Fetters, W. G. Funk, Nikolaos Hadjichristidis, W. W. Graessley

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

71 Scopus citations

Abstract

Several methods for obtaining the size of macromolecules in dilute solution were applied to a series of linear polyisoprenes in the thermodynamically good solvent cyclohexane. The polymers, prepared by anionic polymerization, cover a wide range in molecular weight (1.5 X 104< M < 3.4 X 106) and have narrow molecular weight distributions (Mw/Mn< 1.1). The viscometric radius RVfthe radius of gyration Rg, the hydrodynamic radius RH,and the thermodynamic radius RTwere determined by viscometry and by static and dynamic light scattering. The molecular weight dependences of all four size measures are well-described by power laws (R ∞ Ma). The exponents obtained for RH, RV and RTagree fairly well with the predicted value of 0.588 for good solvents. The exponent obtained for RGis smaller, although RG/RH in fact changes rather little over the range of available data. The values ofRG/RH,RV/RH andRT/RHare in reasonable accord with the theory for self-avoiding coils and with results for polystyrene and poly (α-methylstyrene) in good solvents.

Original languageEnglish (US)
Pages (from-to)2614-2619
Number of pages6
JournalMacromolecules
Volume20
Issue number10
DOIs
StatePublished - Oct 1 1987

ASJC Scopus subject areas

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

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