Mobilities of a drop and an encapsulated squirmer

Area of Science:

• Fluid dynamics
• Soft matter physics
• Microhydrodynamics

Background:

• Microscopic swimmers, like squirmers, are crucial in biological and synthetic systems.
• Understanding squirmer dynamics within fluid interfaces, such as liquid drops, is essential for predicting their behavior.

Purpose of the Study:

• To derive analytical expressions for the motion of a squirmer inside a spherical liquid drop.
• To investigate the anisotropic mobilities of both the squirmer and the drop under external forces and torques.

Main Methods:

• Analysis of squirmer hydrodynamics within a spherical liquid drop.
• Derivation of exact analytical expressions for linear and rotational velocities.
• Consideration of general non-axisymmetric configurations and external stimuli.

Main Results:

• Exact analytical expressions for the velocities of the squirmer and the drop were obtained.
• Mobilities of both squirmer and drop were found to be anisotropic, dependent on orientation and external conditions.
• The influence of squirmer size, position, and fluid viscosities on dynamics was discussed.

Conclusions:

• The study provides a theoretical framework for analyzing the coupled dynamics of a squirmer and a liquid drop.
• Results offer insights into the trajectory and behavior of composite microswimmer systems.
• This work lays the foundation for further research into active matter within fluid interfaces.