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Supporting Information: Accelerated ReaxFF simulations for epoxy cross-linking (parameter tables)

Evidence and attribution

Authority of statements

This PDF is the Supporting Information for 2018vashisth-j-phys-chem-accelerated-reaxff.

Corpus role

Supporting Information for [[2018vashisth-j-phys-chem-accelerated-reaxff]]: full ReaxFF parameter listings and ancillary numerical material; the article states methods, barriers, and properties.

Summary

This Supporting Information PDF publishes the complete ReaxFF parameter listings used in the Journal of Physical Chemistry A article on accelerated epoxy–amine curing for a bisphenol-F diglycidyl ether (bis-F) and DETDA formulation, refined from the CHNO-2017_weak baseline to reproduce quantum-mechanical reaction barriers while also matching experimental density, glass transition temperature, and elastic modulus trends. The corpus treats the document as the bitwise companion to the main article: anyone reproducing the published LAMMPS decks should copy parameter blocks directly from these tables to avoid transcription drift between comma-delimited fields and LAMMPS input syntax. The tables include general and bonded terms exactly as read into LAMMPS for the published workflows, together with ancillary numerical material such as force-parameter scan data and documentation for tracking and post-processing steps associated with quantum-mechanical transition-state cleanup. Interpretive discussion of cure kinetics, mechanical property validation, and bond-boost acceleration strategies remains on [[2018vashisth-j-phys-chem-accelerated-reaxff]]; this file is the numerical appendix for reproducibility.

Methods

This file is Supporting Information for [[2018vashisth-j-phys-chem-accelerated-reaxff]]: its role is tabular reproduction of the ReaxFF parameter set and ancillary numerical inputs used in LAMMPS. Interpretation of cure kinetics, QM benchmarks, accelerated MD logic, and mechanical validation narratives stay on the main article page.

Force-field provenance (SI scope)

  • Parent parameterization / elements: Tables extend the CHNO-2017_weak-class ReaxFF description for bis-F / DETDA epoxy chemistry (C/H/N/O reactive interactions); copy bond, angle, off-diagonal, and charge blocks directly from this PDF when building inputs.
  • QM reference data: The J. Phys. Chem. A article documents QM transition states and barrier targets used to reweight epoxide–amine interactions; the SI lists the resulting ReaxFF numbers rather than re-deriving DFT settings here.
  • Training / fitting targets: Bond dissociation, angle distortion, and reaction-energy points for C–O / C–N / N–H motifs appear in the SI tables as fitted objectives mirroring the article’s QM comparison set.
  • Optimization workflow: Parameter adjustments follow the least-squares / ReaxFF optimization conventions described in the primary text; the SI is not a standalone optimizer log—use the article + these tables together.
  • Experimental validation hooks: Density, \(T_g\), and tensile modulus comparisons to dogbone experiments are summarized in the issue PDF; the SI supplies the force-field side of that pipeline.

MD protocol pointers (defer to main text)

Production LAMMPS settings referenced across the article/SI pair include 0.25 fs integration for \(T_g\) sweeps, alternating NVT / NPT densification, and high strain-rate tensile deformation for modulus ([[2018vashisth-j-phys-chem-accelerated-reaxff]]). Barostat / thermostat damping values and full production segment lengths in ps are enumerated in the Methods of the main paper rather than duplicated in every SI table caption.

MD application (SI document scope)

This Supporting Information file does not define standalone MD cells; the bullets below document what is / is not in this PDF for operators reproducing LAMMPS inputs.

  • Engine / code: LAMMPS-formatted ReaxFF parameter tables (bond/angle/off-diagonal/charge blocks) meant to pair with the issue Methods in [[2018vashisth-j-phys-chem-accelerated-reaxff]].
  • System size & composition: N/A — atom budgets and molecule counts are staged in the main article; this SI is tabular force-field data only.
  • Boundaries / periodicity: N/A — PBC choices and supercell vectors are not re-derived here—copy the periodic LAMMPS cell setup from the primary Methods when building decks from these tables.
  • Ensemble / timestep / duration: N/A — NVT/NPT staging, timestep choices, and ps/ns segment lengths are specified in the JPC A article text, not in every SI caption.
  • Thermostat / barostat: N/A — algorithm labels and damping constants are given in the main Methods; the SI focuses on ReaxFF numbers consumed by those controls.
  • Temperature / pressure targets: N/A — set-point temperature/pressure schedules for production MD are not tabulated as standalone thermal protocols in this SI file—use the issue PDF for 300–600 K annealing ladders, \(T_g\) sweeps, and NPT densification windows referenced there.
  • Electric field / replica / metadynamics: N/A — not part of this SI (electrostatics follow standard ReaxFF/QEq conventions in the supplied LAMMPS decks; acceleration uses restraints per the article).

Findings

The SI underpins the main manuscript’s claims of QM agreement for key elementary reactions, an illustrative trajectory reaching roughly 82% cross-linking, and consistent density, \(T_g\), and modulus behavior relative to laboratory measurements—those headline results should be cited from the issue PDF, not abstracted independently from the SI tables.

Limitations

Parameters are specific to the bis-F/DETDA chemistry and the accelerated-curing workflow; extending them to other epoxies or curing agents requires independent validation. Any discrepancy between proof and issue layouts should be resolved against the publisher version when assigning page-level locators.

Relevance to group

The SI is the bitwise reference for van Duin-group epoxy ReaxFF parameter tables tied to accelerated reactive curing benchmarks, supporting MAS pipelines that ingest publication-specific force fields.

Reader notes (navigation)

Citations and evidence anchors

MAS / retrieval notes

Parameter ingestion should use machine-readable tables from this SI; cite [[2018vashisth-j-phys-chem-accelerated-reaxff]] for tensile and \(T_g\) validation narratives. Bond-boost and restraint keywords in the main text map to supplemental paragraphs here—do not infer barrier heights without QM references listed in the primary article.