Strain Pattern in Supercooled Liquids

Area of Science:

• Condensed Matter Physics
• Materials Science
• Soft Matter Physics

Background:

• Investigations into the glass transition reveal complex phenomena in strain correlations.
• Shear strain fluctuations in liquids can exhibit elastic Eshelby-strain patterns, typically associated with solid-like elastic responses.

Purpose of the Study:

• To investigate the origin and characteristics of Eshelby-strain patterns in supercooled liquids near the glass transition.
• To understand the long-ranged and long-lived nature of these strain signatures.

Main Methods:

• Utilized mode-coupling theory for analyzing strain fluctuations in supercooled liquids.
• Analyzed experimental data from video microscopy of a two-dimensional colloidal glass former.
• Performed simulations of Brownian hard disks to complement theoretical and experimental findings.

Main Results:

• Observed Eshelby-strain patterns [∼cos(4θ)/r^{2}] in shear strain fluctuations, characteristic of elastic response, even in liquids at long times.
• Demonstrated that these strain signatures follow a scaling law near the glass transition.
• Found the Eshelby-strain pattern to be visible on timescales longer than structural relaxation time (τ) and after shear modulus relaxation for sufficiently high viscosities.

Conclusions:

• The presence of Eshelby-strain patterns in supercooled liquids challenges conventional understanding of liquid dynamics at the glass transition.
• These findings highlight the importance of elastic-like correlations in the dynamics of glassy systems.
• The observed scaling law provides a quantitative description of these long-range strain correlations near the glass transition.