Actions for Distribution of Chains in Polymer Brushes Produced by a “Grafting From” Mechanism [electronic resource].

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Distribution of Chains in Polymer Brushes Produced by a “Grafting From” Mechanism [electronic resource].

Published
Washington, D.C. : United States. Dept. of Energy, 2016.
Oak Ridge, Tenn. : Distributed by the Office of Scientific and Technical Information, U.S. Dept. of Energy
Physical Description
pages 547-553 : digital, PDF file
Additional Creators
Oak Ridge National Laboratory, United States. Department of Energy, National Science Foundation (U.S.), and United States. Department of Energy. Office of Scientific and Technical Information
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Summary
The molecular weight and polydispersity of the chains in a polymer brush are critical parameters determining the brush properties. However, the characterization of polymer brushes is hindered by the vanishingly small mass of polymer present in brush layers. In this study, in order to obtain sufficient quantities of polymer for analysis, polymer brushes were grown from high surface area fibrous nylon membranes by ATRP. We synthesized the brushes with varying surface initiator densities, polymerization times, and amounts of sacrificial initiator, then cleaved from the substrate, and analyzed by GPC and NMR. Characterization showed that the surface-grown polymer chains were more polydisperse and had lower average molecular weight compared to solution-grown polymers synthesized concurrently. Furthermore, the molecular weight distribution of the polymer brushes was observed to be bimodal, with a low molecular weight population of chains representing a significant mass fraction of the polymer chains at high surface initiator densities. Moreover, the origin of this low MW polymer fraction is proposed to be the termination of growing chains by recombination during the early stages of polymerization, a mechanism confirmed by molecular dynamics simulations of brush polymerization.
Report Numbers
E 1.99:1261508
Subject(s)
Note
Published through SciTech Connect.
01/11/2016.
Macromolecules 49 2 ISSN 0024-9297 AM
Andre P. Martinez; Jan-Michael Y. Carrillo; Andrey V. Dobrynin; Douglas H. Adamson.
Funding Information
AC05-00OR22725
CHE-1310453
DMR-1004576
View MARC record | catkey: 24056311