Title:
Regular star polymers with 64 and 128 arms. Models for polymeric micelles
Languages of Item:
English
Abstract:
Carbosilane dendrimers with 64 and 128 surface Si-Cl bonds were used as coupling reagents for monodisperse poly(butadienyl)lithium. Two series of regular star polybutadienes with 64 and 128 arms were prepared. The arm molecular weight was varied between 6400 and 72 000. The dilute-solution properties of the stars were determined in a good solvent (cyclohexane) and in a θ-solvent (dioxane) for polybutadiene. Measurements of RG, A2, D0, and [η] indicate that the isolated stars behave as hard spheres. The ratio of the hydrodynamic radius over the radius of gyration is slightly larger than (5/3)1/2. In a comparison which includes previously made stars with lower functionality, it is found that [formula omitted] in the good solvent and f−0.64 in the θ-solvent. The former result is in good agreement with the Daoud-Cotton scaling model of stars. The latter dependence is stronger than the theory predicts: gθ ∝ f−0.5. A recent quantitative model developed by Gast et al. for polymeric micelles is in good agreement with the present experimental data. Stars with many arms represent good model polymers for polymeric micelles. © 1993, American Chemical Society. All rights reserved.
Authors:
Jacques Roovers
Lin Lin Zhou
Paul M. Toporowski
Mark van der Zwan
Hermes Iatrou
Nikos Hadjichristidis
Publisher:
American Chemical Society (ACS)
Keywords:
Micelles; Molecular weight, Daoud-cotton scaling model; Living polymers; Radius of gyration; Star polymers; Theta solvents, Polymers
Main subject category:
Science
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