English
 
Help Privacy Policy Disclaimer
  Advanced SearchBrowse

Item

ITEM ACTIONSEXPORT
  Constrained dynamics in supramolecular structures of poly(p- phenylenes) with ethylene oxide side chains: A combined dielectric and nuclear magnetic resonance investigation

Mierzwa, M., Floudas, G., Neidhöfer, M., Graf, R., Spiess, H. W., Meyer, W. H., et al. (2002). Constrained dynamics in supramolecular structures of poly(p- phenylenes) with ethylene oxide side chains: A combined dielectric and nuclear magnetic resonance investigation. The Journal of Chemical Physics, 117(13), 6289-6299. doi:10.1063/1.1504437.

Item is

Files

show Files

Locators

show

Creators

show
hide
 Creators:
Mierzwa, M.1, Author              
Floudas, G.2, Author              
Neidhöfer, M.3, Author              
Graf, Robert3, Author              
Spiess, Hans Wolfgang3, Author              
Meyer, Wolfgang H.3, Author              
Wegner, Gerhard3, Author              
Affiliations:
1Fdn Res & Technol Hellas, IESL, FORTH, Iraklion 71110, Greece, ou_persistent22              
2Univ Ioannina, Dept Phys, GR-45110 Ioannina, Greece, ou_persistent22              
3MPI for Polymer Research, Max Planck Society, ou_1309545              

Content

show
hide
Free keywords: -
 Abstract: The complex dynamics in supramolecular structures of poly(p- phenylenes) with short ethylene oxide (EO) side chains (known as "hairy rods") have been studied by combining temperature and pressure dependent dielectric spectroscopy (DS) with different nuclear magnetic resonance (NMR) techniques. The system forms a periodic lattice of layers of the main chains separated by layers of the amorphous EO chains. Since the dipole moment is located on the EO side chain, DS is probing mainly the side- chain motions and only indirectly the backbone dynamics. On the other hand, the different NMR techniques are also sensitive to the backbone mobility and provide the molecular origin of the dynamic processes. Two dielectrically active processes exist, a "fast" beta (which differs from the usual Johari-Goldstein beta process found in homopolymers and low molecular weight glass- forming liquids) and a "slow" alpha process with the latter carrying most of the intensity. Comparison of the NMR and dielectric results identifies the outer EO units as solely responsible for the dielectric beta process whereas both the short EO segments and the unfreezing of the internal backbone dynamics including bending motions contribute to the alpha process. The unfreezing of the backbone dynamics does not lead to the dissolution of the structure that only happens at even higher temperatures. Hairy rod molecules thus can serve as model systems which provide the means of studying the effect of confinement on the dynamics. In this respect, the effect of confinement is mainly on the temperature dependence of the alpha-process relaxation times. (C) 2002 American Institute of Physics.

Details

show
hide
Language(s): eng - English
 Dates: 2002-10-01
 Publication Status: Published in print
 Pages: -
 Publishing info: -
 Table of Contents: -
 Rev. Type: No review
 Identifiers: eDoc: 28619
ISI: 000177972400040
Other: P-02-108
DOI: 10.1063/1.1504437
 Degree: -

Event

show

Legal Case

show

Project information

show

Source 1

show
hide
Title: The Journal of Chemical Physics
  Other : J. Chem. Phys.
Source Genre: Journal
 Creator(s):
Affiliations:
Publ. Info: Woodbury, N.Y. : American Institute of Physics
Pages: - Volume / Issue: 117 (13) Sequence Number: - Start / End Page: 6289 - 6299 Identifier: ISSN: 0021-9606
CoNE: https://pure.mpg.de/cone/journals/resource/954922836226