Self-Attractive Semiflexible Polymers under an External Force Field.

Area of Science:

• Polymer Physics
• Soft Matter Physics
• Computational Biophysics

Background:

• Semiflexible polymers exhibit complex behavior influenced by internal interactions and external fields.
• Understanding polymer dynamics is crucial for fields ranging from materials science to molecular biology.

Purpose of the Study:

• To numerically investigate the dynamical response of tethered semiflexible polymers with self-attractive interactions under an external force.
• To explore the effects of varying polymer stiffness and self-interaction strength on chain conformation and response.

Main Methods:

• Numerical simulations were employed to study the polymer's behavior in two spatial dimensions.
• The Brownian multi-particle collision method was used to model the heat bath and polymer-environment interactions.
• Key parameters varied included stiffness and self-interaction strength.

Main Results:

• Equilibrium conformations ranged from compact structures to double-stranded chains and rods, depending on self-attraction and stiffness.
• Under an external force, chains at small rigidities initially compact were unwound before full elongation.
• Double-stranded chains showed a sharp transition from folded to open states, becoming steeper with increased stiffness.

Conclusions:

• The study reveals distinct conformational transitions in semiflexible polymers driven by self-attraction and external forces.
• Discontinuities in force-extension relations and gyration radius distributions characterize these transitions.
• Polymer deformation normal to the force decays inversely with applied force magnitude.