Autophoretic locomotion from geometric asymmetry.

Area of Science:

• Physics
• Chemistry
• Materials Science

Background:

• Self-phoretic microswimmers require chemical gradients for propulsion.
• Designing microswimmers presents challenges in generating controlled motion.

Purpose of the Study:

• To investigate if geometric asymmetries can induce self-propulsion in microswimmers.
• To demonstrate that shape variations are sufficient for generating chemical gradients and net swimming.

Main Methods:

• Exact calculation of self-propulsion speed for a two-sphere system with unequal sizes.
• Asymptotic calculation of self-propulsion velocity for a chemically homogeneous sphere with small-amplitude shape deformations.

Main Results:

• Geometric asymmetries in chemically homogeneous systems can induce self-propulsion.
• Locomotion speeds can be tuned by adjusting geometric asymmetries.
• Significant swimming speeds achieved without chemical patterning.

Conclusions:

• Geometric design is a viable strategy for creating self-propelling microswimmers.
• Shape-induced gradients offer a novel approach to microswimmer propulsion.
• This method bypasses the need for complex chemical patterning.