Abnormal Drop Formation from Copper Films via Detachment.

Area of Science:

• Materials Science
• Surface Science
• Computational Physics

Background:

• Liquid fluids typically merge to minimize surface energy.
• Understanding anomalous fluid behavior is crucial for materials processing.
• Drop formation dynamics on substrates are key to thin-film technologies.

Purpose of the Study:

• To investigate the abnormal drop formation process of liquid copper (Cu) on carbon substrates.
• To elucidate the underlying mechanisms of pinch-off and coalescence in Cu droplet formation.
• To explore the influence of substrate surface structure on Cu drop formation.

Main Methods:

• Utilized molecular dynamics simulations to model the behavior of contacted Cu liquid films.
• Analyzed droplet motion, liquid bridge dynamics, and substrate interactions.
• Examined surface structure effects using mean square displacement, velocity fields, and density/scaling profiles.

Main Results:

• Observed an abnormal drop formation process involving consecutive pinch-off and full coalescence stages.
• Identified dominant droplet motions and liquid bridge dynamics contributing to pinch-off and repeated coalescence.
• Demonstrated that substrate surface structures, particularly carbon nanotubes, influence drop formation behavior.

Conclusions:

• The abnormal Cu drop formation is attributed to the competition between droplet motion and liquid bridge dynamics.
• Surface structure engineering of carbon substrates can control liquid metal drop formation.
• Findings provide guidance for manipulating drop formation in advanced materials applications.