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Title: NMR relaxation of the orientation of single segments in semiflexible dendrimers

We study the orientational properties of labeled segments in semiflexible dendrimers making use of the viscoelastic approach of Dolgushev and Blumen [J. Chem. Phys. 131, 044905 (2009)]. We focus on the segmental orientational autocorrelation functions (ACFs), which are fundamental for the frequency-dependent spin-lattice relaxation times T{sub 1}(ω). We show that semiflexibility leads to an increase of the contribution of large-scale motions to the ACF. This fact influences the position of the maxima of the [1/T{sub 1}]-functions. Thus, going from outer to inner segments, the maxima shift to lower frequencies. Remarkably, this feature is not obtained in the classical bead-spring model of flexible dendrimers, although many experiments on dendrimers manifest such a behavior.
Authors:
;  [1] ;  [2] ; ;  [3]
  1. Faculty of Physics, St. Petersburg State University, Ulyanovskaya Str. 1, Petrodvorets, St. Petersburg, 198504 (Russian Federation)
  2. (Russian Federation)
  3. Theoretical Polymer Physics, University of Freiburg, Hermann-Herder-Str. 3, D-79104 Freiburg (Germany)
Publication Date:
OSTI Identifier:
22311395
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Chemical Physics; Journal Volume: 140; Journal Issue: 24; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; DENDRIMERS; FREQUENCY DEPENDENCE; NUCLEAR MAGNETIC RESONANCE; SPIN-LATTICE RELAXATION