Resolving long-range spatial correlations in jammed colloidal systems using photon correlation imaging

Area of Science:

• Soft Matter Physics
• Materials Science
• Rheology

Background:

• Understanding the dynamics of soft matter is crucial for various applications.
• Jammed systems, such as foams and gels, exhibit complex behaviors governed by particle rearrangements.
• Existing methods often struggle to capture both spatial and temporal dynamics simultaneously.

Purpose of the Study:

• Introduce a novel dynamic light scattering technique, photon correlation imaging.
• Apply this method to investigate the slow dynamics of a coarsening foam and a colloidal gel.
• Characterize the nature and extent of dynamical correlations in these jammed systems.

Main Methods:

• Development of photon correlation imaging, a dynamic light scattering technique.
• Experimental investigation of a quasi-two-dimensional coarsening foam.
• Analysis of a rigid gel network formed by attractive colloidal particles.

Main Results:

• Both foam and gel dynamics are characterized by intermittent rearrangement events.
• Foam rearrangements involve a few bubbles but show correlations up to macroscopic scales.
• Gel dynamics exhibit dynamical correlations extending to the system size.

Conclusions:

• Dynamical correlations can be extremely long-ranged in jammed soft matter systems.
• Mechanical properties play a critical role in determining the nature of these correlations.
• Photon correlation imaging provides a powerful tool for resolving soft matter dynamics in space and time.