The Elevated-Temperature Nano-Mechanical Properties of a PDMS-Silica-Based Superhydrophobic Nanocomposite Coating

This study investigates the elevated-temperature mechanical and viscoelastic properties of a PDMS-silica-based superhydrophobic nanocomposite coating using nanoindentation and a nano-dynamic mechanical analysis over a temperature range of 24 °C to 160 °C. The nanoindentation load-displacement curves exhibited consistent hysteresis, indicating a stable energy dissipation across the temperature range. Creep tests revealed an increased displacement and accelerated deformation at elevated temperatures, displaying a two-stage creep profile characterized by rapid primary and steady-state secondary creep. The hardness decreased with the creep time, while the strain rate sensitivity remained relatively stable, suggesting consistent deformation mechanisms. A time-dependent creep model incorporating linear and logarithmic terms accurately captured the experimental data. The nano-dynamic mechanical analysis results showed a decrease in the storage modulus with depth, while the loss modulus and tan δ peaked at shallow depths. These findings are crucial for the evaluation and design of superhydrophobic nanocomposite coatings.