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Updated: May 19, 2026
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Microfluidic Preparation of Liquid Crystalline Elastomer Actuators
Published on: May 20, 2018
Multiple electrokinetic actuators for feedback control of colloidal crystal size
Jaime J Juárez1, Pramod P Mathai, J Alexander Liddle
1Chemical and Biomolecular Engineering, Johns Hopkins University, Baltimore, MD 21218, USA.
Lab on a Chip
|August 7, 2012
Summary
We developed a feedback control method to precisely assemble colloidal crystals of targeted sizes. This technique precisely controls particle numbers in ensembles, enabling scalable nano- and micro- assembly.
Area of Science:
- Physics
- Materials Science
- Engineering
Background:
- Colloidal crystals are essential in nanotechnology and materials science.
- Precise control over colloidal crystal assembly is challenging.
- Existing methods lack real-time feedback for size targeting.
Purpose of the Study:
- To develop a feedback control method for precise colloidal crystal assembly.
- To demonstrate real-time control over particle number and crystal size.
- To investigate size-dependent properties of assembled colloidal crystals.
Main Methods:
- Utilizing a quadrupole electrode for particle manipulation.
- Implementing a real-time feedback control algorithm based on particle tracking.
- Employing DC-field mediated electrophoretic-electroosmotic transport for particle removal.
- Using AC-field mediated dielectrophoretic transport for particle concentration and assembly.
Main Results:
- Successfully controlled colloidal crystal sizes from 20 to 250 particles with <10% error.
- Demonstrated precise targeting of particle numbers in quasi-2D ensembles.
- Characterized assembled crystals by radius of gyration, crystallinity, and edge particle count.
- Observed expected size-dependent properties in the assembled colloidal crystals.
Conclusions:
- Achieved precise ensemble feedback control over colloidal crystal assembly.
- The developed method enables the creation of different-sized colloidal crystals.
- This approach has broad implications for controlling nano- and micro-scale assembly processes.
