Light-Fueled Nonreciprocal Self-Oscillators for Fluidic Transportation and Coupling

Area of Science:

• Soft robotics
• Non-equilibrium materials science
• Biomimetic engineering

Background:

• Soft actuating materials enable self-sustaining motion in small-scale robotic constructs.
• Existing light-fueled self-oscillators often exhibit reciprocal motion, limiting advanced biomimetic applications like fluidic transport.

Purpose of the Study:

• To report a novel optically powered soft material strip capable of nonreciprocal, cilia-like self-sustained oscillation underwater.
• To demonstrate control over oscillation patterns and fluidic pumping efficiency using light excitation.

Main Methods:

• Utilizing a planar-aligned liquid crystal elastomer actuator responsive to visible light.
• Employing two laser beams from orthogonal directions for piecewise control of strip deformation.
• Coupling two self-shadowing effects within the material to generate nonreciprocal strokes.

Main Results:

• Demonstrated nonreciprocal, cilia-like oscillations underwater.
• Established a connection between nonreciprocity, stroke pattern, handedness, and fluidic pumping efficiency.
• Achieved autonomous microfluidic pumping in both clockwise and anticlockwise directions.
• Showcased translocation of a micro-object and interaction between two oscillating strips.

Conclusions:

• The developed soft actuator offers new concepts for non-equilibrium soft actuators.
• The actuator can perform bio-like functions underwater, including controlled fluidic pumping.
• This research opens avenues for advanced underwater soft robotic applications.