INVESTIGADORES
VACA CHAVEZ FORNASERO Fabian
artículos
Título:
NMR Observation of Entangled Polymer Dynamics: Tube Model Predictions and Constraint Release
Autor/es:
FABIAN VACA CHAVEZ; KAY SAALWAECHTER
Revista:
PHYSICAL REVIEW LETTERS
Editorial:
AMER PHYSICAL SOC
Referencias:
Lugar: New York; Año: 2010 vol. 104 p. 198305 - 198308
ISSN:
0031-9007
Resumen:
We use a benchtop NMR technique to monitor entangled polymer melt dynamics over 5 decades in time covering regimes II?IV of the tube model. We confirm the familiar molar mass scaling exponents of the regime transitions, but we observe a mass-dependent time scaling exponent describing segmental fluctuations in the constrained-Rouse regime II up to high molecular weights. Local chain motions are thus governed by modes that are much less restricted than predicted by the tube model. Diluting protonated chains in deuterated invisible matrix chains, we prove that the exponent is determined by the matrix molecular weight, suggesting constraint-release effects as the origin.