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          Institute: MPI für Polymerforschung     Collection: MPI Polymerforschung     Display Documents

ID: 28565.0, MPI für Polymerforschung / MPI Polymerforschung
Structure and dynamics of nondilute polyfluorene solutions
Authors:Fytas, G.; Nothofer, H. G.; Scherf, Ullrich; Vlassopoulos, D.; Meier, G.
Date of Publication (YYYY-MM-DD):2002-01-15
Title of Journal:Macromolecules
Journal Abbrev.:Macromolecules
Issue / Number:2
Start Page:481
End Page:488
Review Status:No review
Audience:Not Specified
Abstract / Description:The rotational and translational diffusion dynamics of newly synthesized polyfluorenes were studied by dynamic light scattering over a broad concentration range up to the lyotropic state. On the basis of small-angle neutron scattering and translational diffusion measurements in dilute solutions. the single polymers were described as wormlike chains with a low persistent length l = 7 +/- 0.5 nm and cross-section diameter d = 1.8 +/- 0.5 nm. In the semidilute concentration regime, the rate of increase of the cooperative diffusion and the osmotic pressure with c/c* (c* being the overlap concentration) was lower than for linear flexible chains in good solvent. The intermediate scattering function displayed a second process assigned to chain relaxation, in reasonable agreement with the longest relaxation time obtained from shear rheometry. The bimodal shape of the orientation correlation function, which is a characteristic feature of shape persistent polymers and exhibits a peculiar dependence on the scattering angle, was also observed in this model system. The fuzzy cylinder model adequately represented the concentration dependence of the osmotic modulus and the chain orientation time, conforming to the wormlike nature of these polymers.
Comment of the Author/Creator:Date: 2002, JAN 15
External Publication Status:published
Document Type:Article
Affiliations:MPI für Polymerforschung
External Affiliations:FORTH, Inst Elect Struct & Laser, POB 1527, GR-71110 Iraklion, Crete, Greece; Univ Potsdam, Inst Chem, D-14476 Golm, Germany; KFA Julich GmbH, Forschungszentrum, D-52425 Julich, Germany
Identifiers:ISI:000173229600025 [ID No:1]
ISSN:0024-9297 [ID No:2]
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