Spectral shape simplicity of viscous materials

Area of Science:

• Materials Science
• Physical Chemistry
• Rheology

Background:

• Viscoelastic materials exhibit complex relaxation behaviors.
• Understanding the relationship between structure and dynamics in liquids is crucial.
• Previous studies have suggested universality in some liquid properties.

Purpose of the Study:

• To investigate the universality of structural relaxation patterns across diverse liquid types.
• To connect mechanical simplicity in viscoelasticity with fast reorientation dynamics.
• To rationalize the observed universality in relaxation strength versus dielectric response stretching.

Main Methods:

• Analysis of a broad survey of viscoelastic data from various liquid types.
• Comparison of structural relaxation patterns with reorientation dynamics.
• Examination of liquids with and without distinguishable secondary susceptibility peaks.

Main Results:

• A common structural relaxation pattern was identified across van der Waals, hydrogen-bonded, and ionic liquids, as well as polymeric, inorganic, and metallic melts.
• This pattern is largely insensitive to morphological details.
• Mechanical simplicity correlates with fast reorientation dynamics in liquids lacking secondary susceptibility peaks.

Conclusions:

• A generic spectral pattern governs liquid relaxation, unifying diverse material types.
• This generic pattern explains the universality of relaxation strength and dielectric response.
• The findings significantly broaden the understanding of liquid relaxation dynamics.