Competition and Synergy in Programmable Open Microfluidics: Thermal Fields vs Structural Heterogeneities.

Area of Science:

• Microfluidics
• Surface Science
• Materials Science

Background:

• Open microfluidics commonly uses external fields (magnetic, optical, electrical, thermal) for liquid manipulation.
• Thermal fields offer simplicity but their interaction with surface structures is underexplored.

Purpose of the Study:

• To develop a programmable microfluidic platform using heterogeneous structured surfaces and thermal fields.
• To investigate the interplay between thermal fields and surface structure for tunable liquid transport.
• To demonstrate advanced microfluidic operations for diagnostic and synthetic applications.

Main Methods:

• Grafting thermoresponsive macromolecules onto heterogeneous structured surfaces.
• Utilizing global and local thermal fields to control surface wettability.
• Analyzing asymmetric interfacial forces for directional liquid transport.
• Employing localized heating for programmable liquid patterning and reaction cascades.

Main Results:

• Demonstrated tunable directional liquid transport via thermo-mediated wettability.
• Revealed a synergistic mechanism between local thermal fields and structural effects.
• Significantly enhanced antigravity transport critical angle from 2.3° to 41.8°.
• Achieved programmable liquid patterns and cascade chemical reactions using localized heating.

Conclusions:

• Programmable microfluidic platforms with thermoresponsive surfaces offer precise control over liquid motion.
• The synergy between thermal fields and structural effects greatly improves liquid operation performance.
• This approach advances thermal-regulated microfluidics for potential diagnostic and synthetic applications.