Force-Field Benchmark for Polydimethylsiloxane: Density, Heat Capacities, Isothermal Compressibility, Viscosity and Thermal Conductivity

Polysiloxanes are versatile polymeric materials with widespread applications in industries ranging from electronics to biomedical devices due to their unique thermal and viscoelastic properties. Accurate molecular simulations of polysiloxanes are essential for understanding their broad applications from the microscopic perspective. However, the accuracy of these simulations is heavily dependent on the quality of the employed force fields. In this work, we present a comprehensive benchmark and development of force fields tailored for polysiloxanes, with a focus on predicting key thermophysical properties including density, heat capacities, isothermal compressibility, and transport properties such as viscosity, and thermal conductivity. Experimental measurements are performed in parallel to validate simulation outcomes rigorously. Existing force fields for polysiloxanes, including those derived for organic and inorganic systems, are systematically evaluated against experimental data to identify limitations in accuracy and transferability. Simulation results are compared extensively with experimental observations across a range of temperatures and pressures, revealing the strengths and shortcomings of these commonly utilized force fields for polysiloxanes. Discrepancies between force field predictions and experimental measurements are analyzed in detail for thermodynamic and transport properties of polysiloxanes. This benchmark study serves as a critical assessment of current force fields for polysiloxanes and offers guidelines for their further development, enabling more reliable simulations of polysiloxane-based materials for diverse industrial applications.