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Supporting Information: Investigation into the atomistic scale mechanisms responsible for the enhanced dielectric response in the interfacial region of polymer nanocomposites

Summary

This corpus PDF is the Supporting Information for a J. Phys. Chem. C family study (authors include Gonzalez-Valle, Muraleedharan, Zhang, van Duin, Ramos-Alvarado) on atomistic mechanisms behind enhanced dielectric response in alumina-containing polymer nanocomposites. The SI opens with a self-contained description of ReaxFF as a bond-order-dependent potential where connectivity evolves with local geometry, making it suitable for bond formation and cleavage in large reactive systems. It positions ReaxFF as bridging QM accuracy and MD tractability for oxide–polymer interfaces where interfacial chemistry may couple to polarization and dielectric response. The file’s primary role is reproducibility and force-field disclosure for simulations referenced in the main text, not a standalone results article.

Methods

2 — Force-field training (SI disclosure). The parent ReaxFF framework is the standard bond-order-dependent reactive potential. DFT/QM reference data (PBE-level benchmarks where cited) inform energies and reaction targets for the Al/C/H/O N training set of structures and interfacial reactions. Parameter fit / optimization follows ReaxFF least-squares-style fitting to DFT and (where used) experiment validation data. The SI section “ReaxFF method and Al/C/H/O/N parameterization” states that the total energy combines bond-order-dependent contributions (bond, valence angle, torsion) with nonbonded van der Waals and Coulomb for all atom pairs, with EEM-class charge equilibration. MD application in the main article: molecular dynamics in LAMMPS-style runs on alumina–polymer-type slab supercells with PBC / periodic in-plane where used; NVT thermostat-controlled temperature in K; timestep in femtoseconds; production duration in ps or ns; N/A — barostat for stages without NPT; N/A for umbrella sampling unless stated. Hydrostatic pressure / NPT barostat only if their Methods list NPT—else N/A — pressure servicing under NVT windows.

Findings

The SI itself does not substitute for the main article’s quantitative dielectric data, interfacial structure figures, or comparison to experiment. Its findings-level contribution is methodological: it establishes that reactive interfacial MD with the stated Al/C/H/O/N ReaxFF framework is technically feasible at the scales used in the parent work, supporting the paper’s mechanistic narrative on how interfacial chemistry correlates with enhanced dielectric response. Readers should extract numerical permittivity trends, field distributions, and experimental comparisons exclusively from the published article and any additional SI tables there, not from this wiki note alone.

Limitations

extraction_quality is partial because the ingested file is SI-only; the front matter omits the parent DOI—retrieve it from the journal landing page for the corresponding J. Phys. Chem. C article. Permittivity trends, field maps, and main-text figures must be taken from the parent article, not this SI PDF alone. SI PDFs may omit main-text discussion of finite-size effects, sampling convergence, and experimental error bars.

Relevance to group

The work is directly aligned with Penn State ReaxFF practice for oxide–organic interfaces relevant to dielectric polymer nanocomposites. This slug documents which SI blob sits in papers/ for provenance; maintain cross-links to the VOR article slug once a canonical paper: page exists for it.

Citations and evidence anchors

  • Local file: papers/Gonzales_Valle_JPCC_Al2O3_polymer_SI.pdf (SI package; locate parent DOI on ACS for bibliographic citation).