Deformation and fracture of nano-sized metal-coated polymer particles: A molecular dynamics study

• Semi-crystalline lattice method was adopted to construct polyethylene (PE) nanoparticles.
• Compression behaviors of Ni-coated PE nanoparticles were investigated by simulated flat-punch testing.
• Metal-coatings influence the surface structures and dynamics of PE nanoparticles.
• Size effect on the mechanical properties of both Ni-free and Ni-coated PE nanoparticles was determined.
• Thickness of metal-coatings greatly affects the compression behaviors of metal-coated PE nanoparticles.

The mechanical behavior of Ni-coated polyethylene (PE) nanoparticles subjected to compression loading is systemically investigated by classical molecular dynamics simulation. Results show that the Ni coatings on PE nanoparticles lead to a densification of particle surface and remarkably enhance the compression strength. The particle size-effect and the coating thickness effect on the compression responses in terms of compressive strength and particle burst are observed. Burst of Ni-coated PE nanoparticles initiates at the high stress-concentrated grain-boundaries zone of polycrystalline Ni-shell, and propagates along the compression direction to the flattened contact surface, resulting in release of core PE molecules.

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