Eyring theory for plasticity in amorphous polymers violates Curie's principle

Area of Science:

• Condensed Matter Physics
• Polymer Science
• Statistical Mechanics

Background:

• Eyring's 1936 model is foundational for glassy polymer plasticity.
• The Eyring model, while using the concept of activated processes, violates Curie's principle.

Purpose of the Study:

• To identify the fundamental flaw in the Eyring model for plastic flow.
• To propose and validate an alternative model for stress-accelerated dynamics in polymers.
• To reframe the study of glassy polymer plasticity within out-of-equilibrium statistical and condensed matter physics.

Main Methods:

• Critique of the Eyring model based on Curie's principle.
• Application of Landau expansion to model free energy barriers under stress.
• Analysis of the leading quadratic order term in the free energy expansion for α-relaxation.

Main Results:

• The Eyring model is shown to be physically incorrect due to violation of Curie's principle.
• An alternative model, consistent with Curie's principle, accurately describes stress-induced dynamics.
• Experimental evidence supports the proposed model, particularly the role of elastic energy at the nanoscale.

Conclusions:

• The Eyring model is fundamentally flawed for describing glassy polymer plasticity.
• A new theoretical framework based on Landau expansion and Curie's principle provides a more accurate description.
• This work integrates glassy polymer mechanics with advanced concepts in statistical and condensed matter physics.