Droplet Sorting and Manipulation on Patterned Two-Phase Slippery Lubricant-Infused Surface.

Area of Science:

• Materials Science
• Microfluidics
• Surface Chemistry

Background:

• Slippery lubricant-infused surfaces (SLIPS) are composite materials repelling immiscible liquids.
• Different lubricants, like perfluorinated or alkylated oils, can be used based on surface chemistry.
• Patterned SLIPS offer potential for advanced liquid manipulation.

Purpose of the Study:

• To construct patterned slippery surfaces with virtual channels using distinct lubricants.
• To demonstrate preferential water droplet occupation within specific channels.
• To investigate droplet actuation and size-based sorting in these virtual channels.

Main Methods:

• Fabrication of patterned surfaces with virtual channels impregnated with organic and perfluorinated oils.
• Analysis of droplet behavior and forces using a simplified physical model.
• Actuation of droplets via gravity and magnetic fields.
• Development of channel architectures for droplet size sorting.

Main Results:

• Water droplets preferentially occupied organic oil-lubricated virtual channels.
• Droplet cloaking significantly influenced forces when crossing lubricant regions.
• Successful actuation and size-dependent sorting of droplets were achieved.

Conclusions:

• Novel virtual all-liquid channels were formed using patterned lubricant-infused surfaces.
• This approach advances droplet-based microfluidics through controlled droplet manipulation.
• Potential applications exist in biotechnology, diagnostics, and analytical chemistry.