Related Experiment Video
Updated: Nov 9, 2025
06:51
Microparticle Manipulation by Standing Surface Acoustic Waves with Dual-frequency Excitations
Published on: August 21, 2018
7.2K
Light-induced manipulation of passive and active microparticles
Pooja Arya1, Maren Umlandt1, Joachim Jelken1
1Institute of Physics and Astronomy, University of Potsdam, 14476, Potsdam, Germany.
The European Physical Journal. E, Soft Matter
|April 9, 2021
Summary
Light-induced diffusio-osmosis controls particle patterns. This method allows for dynamic, switchable configurations of colloidal particles, enabling novel assembly and manipulation techniques.
Area of Science:
- Colloid Science
- Soft Matter Physics
- Photochemistry
Background:
- Colloidal particles sedimented at solid interfaces are ubiquitous in nature and technology.
- Controlling particle assembly and dynamics at interfaces is crucial for advanced material design.
- Existing methods for manipulating colloidal particles often lack spatial control or reversibility.
Purpose of the Study:
- To investigate the light-induced generation of diffusio-osmotic flow for particle manipulation.
- To demonstrate the creation of dynamic and switchable particle patterns at a solid wall.
- To explore the use of porous colloids in actively generating and responding to light-induced flows.
Main Methods:
- Illumination of particle suspensions with photosensitive ionic surfactants using controlled light beams (wavelength, intensity profile, shape, size).
- Observation and analysis of particle dynamics, including steady and unsteady state configurations.
- Characterization of the emergent diffusio-osmotic flow originating from light-induced surfactant concentration gradients in the electrostatic diffuse layer.
- Comparison of the behavior of nonporous (passive) and porous (active) colloidal particles.
Main Results:
- Light illumination triggers diffusio-osmosis, creating controllable particle patterns at the solid wall.
- Both passive and active colloidal particles exhibit light-controlled dynamics.
- Porous colloids actively contribute to flow generation and exhibit long-range interactions.
- Optical control allows for the creation, splitting, and manipulation of particle assemblies with tunable size and shape.
- Achieved particle states include crystalline packing and dilute lattices.
Conclusions:
- Light-induced diffusio-osmosis offers a novel, non-invasive method for manipulating colloidal particles.
- This technique enables precise control over particle assembly, leading to diverse configurations.
- The findings open new avenues for designing and fabricating complex colloidal structures and materials.
