Molecular dynamics investigation of the nanoindentation performance of PTFE reinforced with DLC coatings

Y Sun and GQ Wang and Q Cheng and JK Li and TQ Yin and BQ Wang, DIAMOND AND RELATED MATERIALS, 158, 112633 (2025).

DOI: 10.1016/j.diamond.2025.112633

Polytetrafluoroethylene (PTFE) exhibits excellent chemical resistance and thermal stability but suffers from poor mechanical strength and thermal degradation under load. To address these limitations, diamond- like carbon (DLC) coatings were investigated as nanoscale reinforcements using molecular dynamics (MD) simulations under nanoindentation conditions. A hierarchical PTFE-DLC composite model with DLC coating revealed significant performance enhancements. The DLC layer reduced volumetric strain by up to 92 % and stabilized potential energy by constraining PTFE molecular motion. Energy analysis showed the DLC coating absorbed indentation energy through controlled bond dissociation, reducing peak temperatures by 20 %. Kinetic energy fluctuations decreased by 75 % under varying velocities, confirming stability. Temperature-dependent simulations demonstrated optimal thermal stability via interfacial heat dissipation, though elevated temperatures increased pair energy, indicating potential trade-offs. These findings establish DLC coatings as effective barriers against deformation and thermal degradation in PTFE, offering mechanistic insights that may inform the design of surface-reinforced PTFE and related polymer systems.

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