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Self-Phoretic Microswimmers Propel at Speeds Dependent upon an Adjacent Surface's Physicochemical Properties
Andrew Leeth Holterhoff1, Mingyang Li1, John G Gibbs1
1Department of Physics and Astronomy , Northern Arizona University , Flagstaff , Arizona 86011 , United States.
The Journal of Physical Chemistry Letters
|August 21, 2018
Summary
Self-phoretic colloids, or microswimmers, move faster when the interface they travel over has reduced osmotic flow. Surface properties like zeta potential and roughness are key to controlling their motion.
Area of Science:
- Colloid science
- Active matter physics
- Nanotechnology
Background:
- Self-phoretic colloids are key components in programmable active matter.
- Most research focuses on particles above a solid/liquid interface, neglecting interface properties.
- The physicochemical qualities of the interface significantly impact particle motion.
Purpose of the Study:
- To investigate how solid interface properties affect the motion of self-phoretic colloids.
- To demonstrate the influence of chemical and physical surface characteristics on particle behavior.
Main Methods:
- Studied titania/silica (TiO2/SiO2) photoactive microswimmers.
- Manipulated local osmotic flow by altering the solid surface's zeta potential and roughness.
- Observed changes in microswimmer speed and behavior.
Main Results:
- Microswimmer speed increased when local osmotic flow over the stationary solid was diminished.
- Reducing zeta potential magnitude led to faster particle movement.
- Increasing surface roughness also enhanced particle speed.
Conclusions:
- Solid surface properties (chemical and physical) are crucial for modeling self-phoretic active matter.
- Altering surface characteristics offers a new method for engineering the kinematic behavior of microswimmers.
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