Microphase Separation and Water Accessibility in Crosslinked Polyurethanes
- 1LAQV-REQUIMTE, Departamento de Química e Bioquímica, Faculdade de Ciências da Universidade do Porto, Rua do Campo Alegre s/n, Porto, Portugal, 4169-007
Abstract
Polyurethane materials are among the most widely used synthetic polymers, yet the atomic-scale structural organisation governing their macroscopic properties remains largely elusive. Despite decades of study, the chain organisation of hard and soft domains in polyurethane remains poorly understood because experimental techniques cannot resolve chain packing and intermolecular interactions at atomistic resolution. Here we combine Monte Carlo-based downsampling of chain length distributions fitted to experimental data with an iterative crosslinking protocol coupled to molecular dynamics relaxation to generate fully atomistic models of heterogeneous polymers with varying crosslinking degrees, using toluene diisocyanate (TDI) and propoxylated glycerol-based polyurethane as a model system. The resulting models reproduce available experimental thermodynamic and structural data, and spontaneously develop microphase separated morphologies consistent with experimental observations. The simulations reveal that hard segment aggregation is a major organisational factor driving microphase separation. Within hard domains, interchain NH· · ·O=C hydrogen bonds dominate cohesive interactions, while atomistic resolution reveals aromatic packing motifs consistent with π-π interactions between aromatic rings in both parallel and perpendicular geometries. At the polyurethane-water interface, urea and amine groups are the most solvent-exposed and retain well-defined hydration shells, whereas urethane linkages remain comparatively shielded. Together, these results provide an atomistic account of hard domain formation and microphase separation in polyurethane, and establish how this morphology governs the accessibility of urethane bonds to catalytic cleavage. The approach provides a framework for investigating structure-property relationships in heterogeneous amorphous polymer systems, with potential applications ranging from enzymatic degradation to materials design.
Related
- Evaporation-Induced Microphase Separation at the Interface of a Sessile Droplet: Formation of a Regular Lattice Pattern.
- Microphase Separation and Ionic Aggregation in Oppositely Charged End-Functionalized Polymer Blends
- 3D‐Printable Nanoporous Thermosets via Disulfide‐Based Polymerization‐Induced Microphase Separation
- Synergistic Effects of Mechanical Properties and Self-Healing in Borate-Based Hydrogen-Bond Dynamic Crosslinked Gels in High-Temperature Water-Based Drilling Fluids
- Reusable UV-crosslinked MIL-101(Fe)@CQD/polymer nanocomposite films for fluorescence detection of As(iii) in water.
BibTeX
@misc{pinto2026microphase,
title = {{Microphase Separation and Water Accessibility in Crosslinked Polyurethanes}},
author = {Alexandre V. Pinto and Pedro A. Fernandes and Maria J. Ramos},
howpublished = {ChemRxiv},
year = {2026},
month = sep,
doi = {10.26434/chemrxiv.15007171/v2},
url = {https://chemrxiv.org/doi/full/10.26434/chemrxiv.15007171/v2},
note = {CC BY},
}
RIS
TY - UNPB
TI - Microphase Separation and Water Accessibility in Crosslinked Polyurethanes
AU - Alexandre V. Pinto
AU - Pedro A. Fernandes
AU - Maria J. Ramos
PY - 2026
DA - 2026/09/09
PB - ChemRxiv
DO - 10.26434/chemrxiv.15007171/v2
UR - https://chemrxiv.org/doi/full/10.26434/chemrxiv.15007171/v2
AB - Polyurethane materials are among the most widely used synthetic polymers, yet the atomic-scale structural organisation governing their macroscopic properties remains largely elusive. Despite decades of study, the chain organisation of hard and soft domains in polyurethane remains poorly understood because experimental techniques cannot resolve chain packing and intermolecular interactions at atomistic resolution. Here we combine Monte Carlo-based downsampling of chain length distributions fitted to experimental data with an iterative crosslinking protocol coupled to molecular dynamics relaxation to generate fully atomistic models of heterogeneous polymers with varying crosslinking degrees, using toluene diisocyanate (TDI) and propoxylated glycerol-based polyurethane as a model system. The resulting models reproduce available experimental thermodynamic and structural data, and spontaneously develop microphase separated morphologies consistent with experimental observations. The simulations reveal that hard segment aggregation is a major organisational factor driving microphase separation. Within hard domains, interchain NH· · ·O=C hydrogen bonds dominate cohesive interactions, while atomistic resolution reveals aromatic packing motifs consistent with π-π interactions between aromatic rings in both parallel and perpendicular geometries. At the polyurethane-water interface, urea and amine groups are the most solvent-exposed and retain well-defined hydration shells, whereas urethane linkages remain comparatively shielded. Together, these results provide an atomistic account of hard domain formation and microphase separation in polyurethane, and establish how this morphology governs the accessibility of urethane bonds to catalytic cleavage. The approach provides a framework for investigating structure-property relationships in heterogeneous amorphous polymer systems, with potential applications ranging from enzymatic degradation to materials design.
ER -