Activated dynamics of semiflexible polymers on structured substrates

Area of Science:

• Soft Matter Physics
• Polymer Physics
• Statistical Mechanics

Background:

• Understanding the dynamics of polymers, particularly semiflexible ones, is crucial in various scientific fields.
• Thermally activated motion and response to external forces are key behaviors influencing polymer configurations and functions.
• Semiflexible polymers like DNA and actin filaments exhibit complex dynamics in confined or patterned environments.

Purpose of the Study:

• To investigate the thermally activated motion of semiflexible polymers in double-well potentials.
• To characterize the properties and dynamics of kink excitations in these systems.
• To determine the influence of bending rigidity and external forces on polymer motion and escape dynamics.

Main Methods:

• Utilized field-theoretic methods to model polymer behavior.
• Calculated the shape, energy, and effective diffusion constant of kink excitations.
• Analyzed the dynamics of kink-antikink pairs for barrier crossing and relaxation processes.

Main Results:

• Kink motion is purely diffusive in symmetric potentials but becomes directed under a driving force.
• The bending rigidity of the polymer significantly affects kink properties and overall motion.
• A critical force threshold is identified for point-like forces to enable polymer barrier crossing.

Conclusions:

• Kink dynamics are fundamental to understanding the activated motion of semiflexible polymers.
• The study provides a framework for predicting polymer behavior under various conditions, including external forces.
• Results are relevant to biopolymers (DNA, actin) and synthetic polyelectrolytes on structured substrates.