Phenomenology of Self-Diffusion in Star-Branched Polyisoprenes in Solution

Ernst von Meerwall*, David H. Tomich, Nikos Hadjichristidis, Lewis J. Fetters

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Scopus citations


We have measured polymer and solvent self-diffusion at 50°C in equiarmed star-branched polyisoprenes of low molecular weights in solution with C6F5Cl and CCl4, using pulsed-gradient spin-echo methods supplemented by NMR T2 relaxation. In solutions and melts of stars with M(arm) ≃ 104 and f ≤ 18, entanglements are less pronounced than in linear polymers of equal molecular weight. Polymer diffusion depends differently on M(arm) and f, the f dependence becoming weak at high f at all solvent concentrations. In dilute solution, diffusion behavior shows that these stars are relatively highly expanded; at high polymer concentrations, segmental diffusion mechanisms begin to contribute. Free volume theories explain solvent but not polymer diffusion.

Original languageEnglish (US)
Pages (from-to)1157-1163
Number of pages7
Issue number4
StatePublished - 1982
Externally publishedYes

ASJC Scopus subject areas

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


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