How surface charges affect interdroplet freezing

Area of Science:

• Surface Science
• Materials Science
• Electrostatics

Background:

• Droplet freezing on surfaces is vital for industries like aviation and transportation.
• Existing research focuses on electrically homogeneous surfaces, where vapor pressure gradients drive freezing propagation.
• The impact of surface electrostatic charge on droplet freezing dynamics remains largely unexplored.

Purpose of the Study:

• To investigate the role of electrostatic charge on surfaces in droplet freezing dynamics.
• To identify and characterize novel freezing phenomena on electrically heterogeneous surfaces.
• To explore the potential of electrostatics in developing advanced anti-icing and antifrosting materials.

Main Methods:

• Theoretical modeling of droplet freezing on electrically heterogeneous surfaces.
• Experimental investigations using various dielectric substrates, liquids, and droplet configurations.
• Analysis of freezing propagation pathways and rates using microscopy and thermal imaging.

Main Results:

• Discovery of an interdroplet freezing relay (IFR) phenomenon on electrically heterogeneous surfaces.
• Observation of a three-dimensional, in-air freezing propagation pathway.
• Demonstration of accelerated freezing rates due to surface charge gradients and ice needle formation.
• Confirmation of the phenomenon's generality across different materials and conditions.

Conclusions:

• Surface charge gradients on electrically heterogeneous surfaces significantly influence droplet freezing dynamics.
• The IFR phenomenon, driven by electrostatics, offers a new mechanism for rapid frost formation.
• Electrostatic interactions are pivotal for designing next-generation passive anti-icing and antifrosting materials.