Speakers - 2026

Title: Dynamic behavior of water nanodroplets on inclined au(100) surfaces: Influence of tilt angle on motion and deformation

Abstract

This study investigates the dynamic behavior of a water nanodroplet on an inclined Au(100) surface using molecular dynamics simulations. Understanding this behavior is essential for controlling droplet motion and deformation at the nanoscale, with potential applications in advanced nanofluidic systems, functional surfaces, and nanoscale sensing technologies. The nanodroplet consisted of 5000 water molecules and was studied at tilt angles of 11°, 22°, 33°, 55°, 66°, and 77°. An external force was applied to the droplet and decomposed into horizontal (parallel to the surface) and vertical (perpendicular to the surface) components. With increasing inclination, the horizontal component decreases while the vertical component increases. The droplet dynamics exhibit three main stages: Initiation Stage (droplet contacts the surface while maintaining an approximately spherical shape), Detachment Stage (droplet slightly lifts off and begins deformation), and Spreading Stage (droplet elongates along the incline and spreads on the surface). Horizontal displacement of the droplet’s center of mass decreases with increasing inclination, while vertical displacement increases. Hydrogen bonding initially rises, then decreases, and fluctuates around an equilibrium value. Density profiles show higher density at the droplet center initially, complex non-uniformity in intermediate stages, and increased density near the surface at later stages, with steeper inclinations leading to greater accumulation due to stronger vertical forces. Total downward displacement does not follow a linear trend with inclination due to the interplay between decreasing horizontal force, increased deformation, and surface adhesion. These findings provide valuable insights for the design of surfaces that precisely manipulate nanoscale fluids, enabling applications in nanofluidics, smart surfaces, lab-on-a-chip devices, and nanoscale sensors.

The audience take away from presentation:

• Understanding of nanoscale droplet dynamics on inclined surfaces.
• How surface tilt affects center-of-mass motion, spreading, and density profiles.
• Insights into hydrogen bonding dynamics during droplet motion.
• Design principles for functional surfaces in nanofluidics and sensing applications.
• Implications for controlling nanoscale fluid behavior using surface geometry and external forces.