From Notch-Tip Stress to Mechanophore Activation - A Multiscale Study of Mechanochromic PMMA
Abstract
Mechanophore-functionalized polymers enable optical readout of molecular-level stress under macroscopic deformation. Spiropyran (SP)-doped poly(methyl methacrylate) (PMMA) provides a well-established platform for mechanochemical stress sensing, yet molecular stress fields around defined geometric stress concentrators remain largely disconnected from continuum mechanics. To bridge this gap, we develop a geometry-matched molecular dynamics (MD) and finite-element (FE) approach for PMMA containing two opposing semi-elliptical notches of systematically varied depth and width. Molecular simulations employ a hybrid coarse-grained/all-atom (CG/AA) PMMA model with atomistically resolved, quantum-chemically (QC) informed SP, while the FE models use the MD-derived stress–strain response of bulk PMMA as input. Under uniaxial tension, both approaches capture notch-tip stress localization, plastic-zone propagation toward the ligament center, and the characteristic butterfly-shaped stress field. FE simulations reproduce MD notch-tip stresses, demonstrating that suitably parameterized continuum models capture key notch mechanics, whereas defect-mediated rearrangements require molecular resolution. Notch geometry strongly enhances SP activation to its merocyanine (MC) form, lowering the onset strain and localizing activation in highly elongated chains and around deformation-induced voids near the notch edges. These results link defect geometry and molecular stress concentration to mechanophore activation and directly connect molecular and continuum notch mechanics.
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BibTeX
@misc{dellwisch2026from,
title = {{From Notch-Tip Stress to Mechanophore Activation - A Multiscale Study of Mechanochromic PMMA}},
author = {Alexander Dellwisch and Florian Bischoff and Lucio Colombi Ciacchi and Tim Neudecker},
howpublished = {ChemRxiv},
year = {2026},
month = oct,
doi = {10.26434/chemrxiv.15010613/v1},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010613/v1},
note = {CC BY},
}
RIS
TY - UNPB
TI - From Notch-Tip Stress to Mechanophore Activation - A Multiscale Study of Mechanochromic PMMA
AU - Alexander Dellwisch
AU - Florian Bischoff
AU - Lucio Colombi Ciacchi
AU - Tim Neudecker
PY - 2026
DA - 2026/10/16
PB - ChemRxiv
DO - 10.26434/chemrxiv.15010613/v1
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010613/v1
AB - Mechanophore-functionalized polymers enable optical readout of molecular-level stress under macroscopic deformation. Spiropyran (SP)-doped poly(methyl methacrylate) (PMMA) provides a well-established platform for mechanochemical stress sensing, yet molecular stress fields around defined geometric stress concentrators remain largely disconnected from continuum mechanics. To bridge this gap, we develop a geometry-matched molecular dynamics (MD) and finite-element (FE) approach for PMMA containing two opposing semi-elliptical notches of systematically varied depth and width. Molecular simulations employ a hybrid coarse-grained/all-atom (CG/AA) PMMA model with atomistically resolved, quantum-chemically (QC) informed SP, while the FE models use the MD-derived stress–strain response of bulk PMMA as input. Under uniaxial tension, both approaches capture notch-tip stress localization, plastic-zone propagation toward the ligament center, and the characteristic butterfly-shaped stress field. FE simulations reproduce MD notch-tip stresses, demonstrating that suitably parameterized continuum models capture key notch mechanics, whereas defect-mediated rearrangements require molecular resolution. Notch geometry strongly enhances SP activation to its merocyanine (MC) form, lowering the onset strain and localizing activation in highly elongated chains and around deformation-induced voids near the notch edges. These results link defect geometry and molecular stress concentration to mechanophore activation and directly connect molecular and continuum notch mechanics.
ER -