A Coarse-Grained Molecular Dynamics Model for Analysis of Mesoscale Carbon Nanothread Structures

Diamond nanothreads (DNTs) represent a promising class of one-dimensional carbon nanomaterials for next-generation structural applications. However, exploring their mesoscale collective properties remains computationally prohibitive via all-atomistic molecular dynamics (MD) simulations. Here, we present a physically consistent coarse-grained model tailored for both zigzag (DNT-I) and tubular (DNT-II) nanothreads. By establishing an energy equivalence framework between all-atomistic MD simulations and molecular mechanics, the bonded potentials (stretching and bending) and non-bonded Lennard-Jones parameters were derived. Moreover, a degree of coarse-graining r₀ = 6 Å was determined, which well preserves the interfacial cohesive energy and axial sliding behavior of all-atomistic models. Using the established coarse-grained potentials of DNTs, a high glass transition temperature (T_g = 1485 K) was predicted, and a cooperative intermolecular sliding mechanism that governs the plastic deformation of crystalline DNT aggregates under uniaxial tension was revealed.