Thermal transport at a nanoparticle-water interface: A molecular dynamics and continuum modeling study

Area of Science:

• Nanoscale heat transfer
• Computational physics
• Materials science

Background:

• Understanding heat transfer at the nanoscale is critical for applications like nanofluids and photothermal therapy.
• Accurate modeling of nanoparticle-solvent interactions is essential for predicting thermal behavior.

Purpose of the Study:

• To investigate heat transfer dynamics between a silver nanoparticle and surrounding water using molecular dynamics (MD) simulations.
• To calculate the thermal conductance (Kapitza conductance) at the nanoparticle-water interface.
• To compare different simulation approaches for heat transfer analysis.

Main Methods:

• Molecular dynamics (MD) simulations were employed to model heat transfer.
• Four distinct computational approaches were used: transient (with/without temperature gradient) and steady-state non-equilibrium and equilibrium simulations.
• A continuum solid-like model was introduced to analyze heat conduction in water shells around the nanoparticle.

Main Results:

• Steady-state and equilibrium simulation results for thermal conductance were consistent, but differed from transient methods.
• Heat dissipation from a hot silver nanoparticle into water occurs within ~2 nm and <5 ps.
• Local thermal conductivity of water near the nanoparticle was found to be approximately 50% higher than bulk water.

Conclusions:

• MD simulations provide valuable insights into nanoscale heat transfer mechanisms.
• The study highlights the importance of accurate local thermal property descriptions in aqueous environments for nanofluid and photothermal therapy applications.