Microscopic origin of the Baumgärtel-Schausberger-Winter Relaxation Spectrum in Polymer Melts and Particle Rafts
Abstract
Entangled polymer melts exhibit the robust two-branch Baumgärtel-Schausberger-Winter (BSW) relaxation spectrum, while related spectra occur in nonpolymeric monodisperse disordered systems. In spite of the successful application of BSW to many different materials, a molecular derivation of these spectra is lacking. We construct a molecular theory in which a chain segment moves relative to a screened, dynamically responding multichain environment. Gaussian-chain preaveraging gives Mseg(Δm)∼(Δm)−1/2, hence λp∼ p3/2 and, after stress projection, H(τ)∼τ−2/3. Independently, longitudinal primitive-path diffusion gives contour-length fluctuations with H(τ)∼τ1/4. A molecular-weight-constrained implementation is tested simultaneously against experimental G'(ω) and G''(ω) data for four monodisperse polybutadiene (PBD) melts, without fitting spectral exponents or individual modal weights. The resulting BSW spectrum exhibits a continuous transfer from the fast cooperative to the slow constraint-renewal cascade before a finite-chain terminal edge. A common two-sector caged dynamics then connects polymers to particle rafts without assuming identical microscopic mechanisms.
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BibTeX
@misc{nichetti2026microscopic,
title = {{Microscopic origin of the Baumgärtel-Schausberger-Winter Relaxation Spectrum in Polymer Melts and Particle Rafts}},
author = {Dario Nichetti and H. Henning Winter and Alessio Zaccone},
howpublished = {arXiv},
year = {2026},
month = sep,
doi = {10.48550/arxiv.2609.29720},
eprint = {2609.29720},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2609.29720},
}
RIS
TY - UNPB
TI - Microscopic origin of the Baumgärtel-Schausberger-Winter Relaxation Spectrum in Polymer Melts and Particle Rafts
AU - Dario Nichetti
AU - H. Henning Winter
AU - Alessio Zaccone
PY - 2026
DA - 2026/09/24
PB - arXiv
DO - 10.48550/arxiv.2609.29720
UR - https://arxiv.org/abs/2609.29720
AB - Entangled polymer melts exhibit the robust two-branch Baumgärtel-Schausberger-Winter (BSW) relaxation spectrum, while related spectra occur in nonpolymeric monodisperse disordered systems. In spite of the successful application of BSW to many different materials, a molecular derivation of these spectra is lacking. We construct a molecular theory in which a chain segment moves relative to a screened, dynamically responding multichain environment. Gaussian-chain preaveraging gives M_seg(Δm)∼(Δm)^−1/2, hence λ_p∼ p^3/2 and, after stress projection, H(τ)∼τ^−2/3. Independently, longitudinal primitive-path diffusion gives contour-length fluctuations with H(τ)∼τ^1/4. A molecular-weight-constrained implementation is tested simultaneously against experimental G'(ω) and G''(ω) data for four monodisperse polybutadiene (PBD) melts, without fitting spectral exponents or individual modal weights. The resulting BSW spectrum exhibits a continuous transfer from the fast cooperative to the slow constraint-renewal cascade before a finite-chain terminal edge. A common two-sector caged dynamics then connects polymers to particle rafts without assuming identical microscopic mechanisms.
ER -