Debundling and dispersion of carbon nanotubes (CNTs) in polymer solutions play a major role the preparation nanofibers due to early effects on interfacial ordering mechanical properties. A roadblock toward ultrastrong fibers is difficulty achieve homogeneous dispersions CNTs polyacrylonitrile (PAN) poly(methyl methacrylate) (PMMA) precursor solvents such as dimethyl sulfoxide (DMSO), N,N-dimethylacetamide (DMAc), N,N-dimethylformamide (DMF). In this contribution, molecular dynamics...

REACTER is a heuristic protocol that allows complex, predefined reactions to be modeled in atomistic, fixed-valence molecular dynamics (MD) simulations. The method applicable broad range of chemical and permits much larger longer reactive simulations than existing approaches. One or more competing multistep series can invoked simultaneously. Special treatment applied neighboring atoms relax high-energy configurations while the simulation progresses. original implementation REACTER, which was...

Generating simulation-ready molecular models for the LAMMPS dynamics (MD) simulation software package is a difficult task and impedes more widespread efficient use of MD in materials design development. Fixed-bond force fields generally require manual assignment atom types, bonded interactions, charges, domain sizes. A new pre- postprocessing toolkit (LUNAR) presented that efficiently builds systems LAMMPS. LUNAR automatically assigns generates provides initial configuration methods to...

The complex structural and chemical changes that occur during polymerization pyrolysis critically affect material properties but are difficult to characterize in situ. This work presents a novel, experimentally validated methodology for modeling the complete processes phenolic resin using reactive molecular dynamics. simulations produced polymerized structures with mass densities of 1.24 ± 0.01 g/cm3 Young's moduli 3.50 0.64 GPa, which good agreement experimental values. subsequently...

New functionality is added to the LAMMPS molecular simulation package, which increases versatility with can interface supporting software and manipulate information associated bonded force fields. We introduce "type label" framework that allows atom types their higher-order interactions (bonds, angles, dihedrals, impropers) be represented in terms of standard type strings a field. Type labels increase human readability input files, enable fields supported by OpenKIM repository, simplify...

Polyacrylonitrile (PAN)/carbon nanotube (CNT) composites are used as precursors for ultrastrong and lightweight carbon fibers. However, insights into the structure at nanoscale relationships to mechanical thermal properties have remained difficult obtain. In this study, molecular dynamics simulation with accurate potentials available experimental data were describe influence of different degrees PAN preorientation CNT diameter on atomic-scale composites. The inclusion CNTs in polymer matrix...

The long‐term stability of direct carbon fuel cells, based on solid oxide cells with molten Sb and Sb–Bi anodes, was examined for operation activated charcoal, rice starch, bio‐oil fuels at 973 K. With intermittent stirring the fuel–metal anode interface, performance stable, reasonable power densities (∼250 mW/cm 2 ) were achieved periods up to 250 h. Sc‐stabilized zirconia, severe thinning electrolyte occurred in regions high current flow. No observed yttria‐stabilized zirconia as operating...

Abstract Polyacrylonitrile (PAN) is among the most promising precursor polymers to produce strong and lightweight carbon fiber. Conformations in solution extent of binding nanotubes (CNTs) are critical during gel spinning for alignment graphitic layers upon carbonization. Here, quantitative insights into these processes reported using molecular dynamics simulations at atomic scale including virtual π electrons comparisons experimental data. Common solvents fiber induce significant...

Glassy carbon (GC) material derived from pyrolyzed furan resin was modeled by using reactive molecular dynamics (MD) simulations. The MD polymerization simulation protocols to cure the precursor are validated via comparison of predicted density and Young's modulus with experimental values. pyrolysis simulations pyrolyze is calculated density, modulus, content, sp2 in-plane crystallite size, out-of-plane stacking height, interplanar spacing results literature for GC. modeling methodology...

We describe the dynamics of gellan strands in solution, interaction mechanisms with clay platelets different composition, and design principles to tune attraction.

Generating molecular models for the LAMMPS dynamics (MD) simulation software package is a difficult task and an impediment to more widespread efficient use of MD in materials design development. Fixed-bond force fields generally require manual assignment atom types, bonded interactions, charges, domain sizes. A new pre- post-processing toolkit (LUNAR) presented that efficiently builds systems LAMMPS. LUNAR automatically assigns generates charges provides initial configuration methods...

Polyamide membranes are widely used in reverse osmosis (RO) water treatment, yet the mechanism of interfacial polymerization during membrane formation is not fully understood. In this work, we perform atomistic molecular dynamics simulations to explore cross-linking trimesoyl chloride (TMC) and m-phenylenediamine (MPD) monomers at aqueous–organic interface. Our studies show that solution interface provides a function "concentration dispersion" for cross-linking. The process starts with rapid...

The interfacial behaviour of surfactant-laden drops squeezing through tight constrictions in a uniform far-field flow is modelled with respect to capillary number, drop-to-medium viscosity ratio and surfactant contamination. treated as insoluble non-diffusive, drop surface tension related concentration by linear equation state. constriction formed three solid spheres held rigidly space. A characteristic aspect this confined contaminated multiphase system the rapid development steep...

Abstract

The internal flow and mixing properties inside deformable droplets, after reaching the steady state within two types of passive droplet traps, are visualized analyzed as dynamical systems. first trap (constriction) is formed by three spheres arranged in an equilateral triangle, while second consists parallel spherocylinders (capsules). systems assumed to be embedded a uniform far-field at low Reynolds number, shapes interfacial velocities on drops generated using boundary-integral method....

New functionality is added to the LAMMPS molecular simulation package that increases versatility with which can interface supporting software and manipulate information associated bonded force fields. We introduce “type label” framework allows atom types their higher-order interactions (bonds, angles, dihedrals, impropers) be represented in terms of standard type strings a field. Type labels increase human readability input files, enable fields supported by OpenKIM repository, simplify...

Glassy carbon (GC) materials demonstrate excellent thermal stability and mechanical response with low mass densities, which makes them candidates for use in ablatives carbon-carbon composites (C/C composites) used aerospace hypersonic vehicle structures. Although GC have been development decades, molecular simulation protocols need to be developed accelerate the optimization of processing cycles drive next generation C/C composites. The objective this research is establish reactive dynamics...

High-resolution, long-time three-dimensional simulations are presented for slow, pressure-driven flow of a periodic emulsion deformable drops through dense, simple cubic array solid spheres (one drop and one particle per cell). The drops, covered with insoluble, non-diffusive surfactant, large compared pores, they squeeze high resistance, very closely coating the solids to overcome surface tension lubrication effects. volume fraction is 50 %, concentration $c_{em}$ in pore space 36 % or...

The complex structural and chemical changes that occur during polymerization pyrolysis critically affect material properties but are difficult to characterize in situ. This work presents a novel, experimentally validated methodology for modeling the complete processes phenolic resin using reactive molecular dynamics. simulations produced polymerized structures with mass densities of 1.24 ± 0.01 g/cm3 Young’s moduli 3.50 0.64 GPa, which good agreement experimental values. subsequently...