Surface-Induced Constraint Release in Confined Polymer Films: A Computational Phenomenological Study
- 1Department of Chemical Engineering
- 2Texas Tech University
Abstract
Thin polymer films exhibit thickness-dependent viscoelastic behavior attributed to enhanced segmental mobility near free surfaces, a phenomenon recently linked to surface-induced constraint release (SICR) in entangled polymer melts. While self-consistent theoretical treatments of this mechanism exist, computationally lightweight phenomenological models that isolate the role of specific structural assumptions remain comparatively underexplored. This work showcases a developed closed-form, depth-resolved generalized Maxwell model in which local relaxation times are derived from a depth-dependent entanglement molecular weight profile, motivated by reptation scaling () and literature-reported surface entanglement enhancement ratios. With this framework, we directly compare two assumptions for combining depth-dependent relaxation behavior into an effective film modulus: a depth-independent linear superposition, and an entanglement-coupled, double-reptation-inspired mixing rule. Holding the underlying relaxation-time profile identical between both models, we find that the choice of coupling mechanism alters the predicted storage modulus by up to ~40%, with the divergence peaking at an intermediate film thickness rather than increasing monotonically as films thin. This work shows that the peak location is associated with, though not fully predicted by, the frequency-dependent heterogeneity of local relaxation times across the film. These results indicate that depth-coupling assumptions in phenomenological thin-film rheology models are not a minor implementation detail, but materially and non-trivially shape predicted thickness-dependent behavior, with implications for how such models should be constructed and interpreted going forward.
Related
- Surface-Confined Steric Frustration Directs One-Dimensional BisNHC Assembly
- Anomalous Enhancement in MXene‐Based Electrochemical Actuators: Pseudo‐Capacitance‐Induced Multi‐Charge Accumulation in Confined Space
- CO2-Induced Shifts in the Confined Phase Transformation of CH4 in Metal-Organic Frameworks
- Integrated Experimental and Computational Investigation of Fluorinated Benzoylthiourea Derivatives: Structural Characterization, Hirshfeld Surface Analysis, Antioxidant Activity, and MAO–B Inhibitory Potential for Parkinson’s Disease
- Crystal structure, Hirshfeld surface analysis, computational study, molecular docking predictions and biological evaluation of a new Schiff base (E)-2-((2,4-dichlorobenzylidene)amino)aniline
BibTeX
@misc{castillo2026surfaceinduced,
title = {{Surface-Induced Constraint Release in Confined Polymer Films: A Computational Phenomenological Study}},
author = {Michael Castillo},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15008940/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008940/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - Surface-Induced Constraint Release in Confined Polymer Films: A Computational Phenomenological Study
AU - Michael Castillo
PY - 2026
DA - 2026/09/16
PB - ChemRxiv
DO - 10.26434/chemrxiv.15008940/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15008940/v1
AB - Thin polymer films exhibit thickness-dependent viscoelastic behavior attributed to enhanced segmental mobility near free surfaces, a phenomenon recently linked to surface-induced constraint release (SICR) in entangled polymer melts. While self-consistent theoretical treatments of this mechanism exist, computationally lightweight phenomenological models that isolate the role of specific structural assumptions remain comparatively underexplored. This work showcases a developed closed-form, depth-resolved generalized Maxwell model in which local relaxation times are derived from a depth-dependent entanglement molecular weight profile, motivated by reptation scaling () and literature-reported surface entanglement enhancement ratios. With this framework, we directly compare two assumptions for combining depth-dependent relaxation behavior into an effective film modulus: a depth-independent linear superposition, and an entanglement-coupled, double-reptation-inspired mixing rule. Holding the underlying relaxation-time profile identical between both models, we find that the choice of coupling mechanism alters the predicted storage modulus by up to ~40%, with the divergence peaking at an intermediate film thickness rather than increasing monotonically as films thin. This work shows that the peak location is associated with, though not fully predicted by, the frequency-dependent heterogeneity of local relaxation times across the film. These results indicate that depth-coupling assumptions in phenomenological thin-film rheology models are not a minor implementation detail, but materially and non-trivially shape predicted thickness-dependent behavior, with implications for how such models should be constructed and interpreted going forward.
ER -