Wetting Ridge-Guided Directional Water Self-Transport

Area of Science:

• Surface Science and Engineering
• Microfluidics and Lab-on-a-Chip Technologies
• Materials Science

Background:

• Directional water self-transport is vital for applications like biosensing and water harvesting.
• Existing methods face limitations in self-driving distance, functionality, and fabrication complexity.
• Superwettability surfaces offer potential for controlled fluid manipulation.

Purpose of the Study:

• To propose and demonstrate a novel lubricant-infused heterogeneous superwettability surface (LIHSS) for efficient directional water self-transport.
• To overcome the limitations of short self-driving distances and single functionality in current strategies.
• To provide a simplified fabrication method for advanced water manipulation platforms.

Main Methods:

• Fabrication of LIHSS on polyimide (PI) film using femtosecond laser direct writing.
• Tuning PI film wettability to achieve superhydrophobic and superhydrophilic states.
• Infusion of lubricant to create an asymmetrical wetting ridge for capillary force-driven transport.

Main Results:

• Achieved a maximum droplet self-driving distance of approximately 3 mm, nearly double previous records.
• Demonstrated directional water self-transport, anti-gravity pumping, and chemical microreaction capabilities on a tilted surface.
• Successfully transformed PI film wettability via precise femtosecond laser parameter control.

Conclusions:

• The developed LIHSS provides an efficient and promising platform for directional water self-transport.
• This strategy offers enhanced droplet transport distance and multi-functional capabilities.
• The fabrication method is efficient and adaptable for creating advanced microfluidic devices.