Processing soft thin films on liquid surface for seamless creation of on-liquid walkable devices

Area of Science:

• Materials Science and Engineering
• Soft Robotics
• Fluid Dynamics

Background:

• Insects exhibit unique on-liquid locomotion, but engineering similar devices is complex, requiring multistage fabrication and delicate deployment.
• Current methods for creating soft films on liquid surfaces are often disjointed and lack seamless integration.

Purpose of the Study:

• To introduce HydroSpread, a direct processing technology for seamless fabrication and patterning of soft films directly on liquid surfaces.
• To develop functional on-liquid walkable devices by leveraging novel locomotion mechanisms.

Main Methods:

• HydroSpread technology utilizes controlled spreading of liquid ink on a liquid surface combined with laser engraving and rapid heat transfer.
• Fabrication of various geometric shapes and complex patterns with high fidelity.
• Investigation of heat-driven hydrodynamic locomotion mechanisms: fin-like bending and leg-like buckling.

Main Results:

• Successful fabrication of intricate patterns on liquid surfaces using HydroSpread.
• Engineering of two on-water walkable devices, HydroFlexor and HydroBuckler, demonstrating robust locomotion.
• Demonstration of fin-like bending and leg-like buckling as effective heat-driven locomotion principles.

Conclusions:

• HydroSpread technology streamlines soft device manufacturing by eliminating fragile postfabrication transfers.
• This work bridges the gap between soft film fabrication and structural design for liquid environments.
• Establishes a simplified pathway for designing and deploying functional soft devices directly on liquid surfaces.