Single-Cell Mapping of Colloidal Phase Transitions via Dielectrophoretic Control of Particle Concentration

Area of Science:

• Condensed matter physics
• Colloidal science
• Soft matter physics

Background:

• Colloidal systems are valuable for studying condensed matter behavior.
• Dielectrophoresis (DEP) has been used for colloid crystallization.
• Systematic resolution of multiple phase transitions in colloids is underexplored.

Purpose of the Study:

• To develop a unified single-sample platform for studying colloidal phase transitions.
• To enable continuous and reversible modulation of volume fraction and interparticle potential.
• To explore the potential of DEP for resolving multiple phase transitions.

Main Methods:

• Utilized dielectrophoresis (DEP) with electric field gradients.
• Employed surfactant-controlled ionic strength for modulation.
• Employed real-time confocal microscopy and quantitative structural analysis.

Main Results:

• Accessed various phase states including liquid-BCC, BCC-FCC, and melting.
• Demonstrated continuous and reversible modulation of system parameters.
• Tracked the evolution of order and captured reversible transitions in situ.

Conclusions:

• The developed platform provides a powerful tool for studying colloidal phase transitions.
• Demonstrated controllable switching between distinct crystal symmetries and phase boundaries.
• Offers new possibilities for investigating nonequilibrium transitions and interface dynamics in colloidal systems.