Evolution of Self-Propelled Objects: From the Viewpoint of Nonlinear Science

Area of Science:

• Physical Chemistry
• Materials Science
• Chemical Engineering

Background:

• Chemical energy drives various self-propelled objects.
• Interfacial tension is a key factor in self-propulsion mechanisms.

Purpose of the Study:

• To review self-propelled objects driven by interfacial tension.
• To explain basic mechanisms and extended behaviors of these objects.

Main Methods:

• Focus on three basic mechanisms: surface tension difference, contact angle difference, and axisymmetric swirling flow.
• Discuss extension of simple behaviors by coupling with chemical reactions or increasing object numbers.

Main Results:

• Self-propelled objects can exhibit reciprocating motion, oscillatory motion, and spatiotemporal pattern formation.
• Extended systems show characteristic nonlinear behaviors.

Conclusions:

• Understanding interfacial tension-driven self-propulsion is crucial for developing advanced functional materials.
• This review aids chemists in studying self-propelled objects with biological system-like functions.