Anomalous critical slowdown at a first order phase transition in single polymer chains

Area of Science:

• Polymer physics
• Soft matter physics
• Statistical mechanics

Background:

• Polymers grafted to surfaces exhibit complex behavior near phase transitions.
• Mechanically induced adsorption-stretching transitions are crucial in understanding polymer-surface interactions.
• First-order transitions typically involve discontinuous changes, but dynamical behavior can be more nuanced.

Purpose of the Study:

• To investigate the dynamical behavior of a grafted polymer near a mechanically induced adsorption-stretching transition.
• To characterize the relaxation dynamics as the transition point is approached.
• To develop a theoretical model explaining the observed phenomena.

Main Methods:

• Brownian dynamics simulations were employed to model the polymer system.
• Analysis focused on the characteristic relaxation times and their dependence on proximity to the transition.
• A dynamic effective interface model was developed and validated against simulation data.

Main Results:

• The study observed a power-law growth in characteristic relaxation time as the adsorption-stretching transition point was approached.
• Despite the transition being first-order, an anomalous slowdown in dynamics was detected.
• The dynamic effective interface model quantitatively reproduced the simulation results.

Conclusions:

• The findings suggest an unconventional mixing of first-order transition characteristics (order parameter jump) and critical point features (anomalous slowdown).
• This phenomenon may be common in force-driven phase transitions of macromolecules.
• The developed theoretical model provides a generic framework for understanding such transitions.