Dissipative response of driven bead-spring-dashpot chains

Area of Science:

• Polymer physics
• Computational biophysics
• Soft matter physics

Background:

• Understanding energy dissipation in polymers is crucial for predicting their mechanical behavior.
• Internal friction significantly impacts polymer dynamics and macroscopic properties.
• Previous models often simplify polymer chains, limiting their applicability to complex systems.

Purpose of the Study:

• To numerically calculate the work dissipated when pulling a polymer chain with internal friction.
• To investigate how dissipation varies with chain length, pulling stiffness, and internal friction.
• To compare the behavior of multi-mode (N>1) chains with single-mode (N=1) models.

Main Methods:

• Numerical calculation of dissipated work using a sequence of N spring-dashpot elements.
• Modeling polymer chains pulled by a harmonic trap under linear and symmetric protocols.
• Systematic examination of parameters including chain length (N), pulling trap stiffness, and internal friction coefficient.

Main Results:

• Dissipation increases with chain length (N) for polymers without internal friction.
• For chains with internal friction, the relationship between dissipation and N is dependent on the pulling trap stiffness.
• Dissipation decreases (increases) with N as pulling stiffness increases (decreases) for internal friction cases.

Conclusions:

• The simple relationship between damping and dissipated work seen in single-mode models does not hold for multi-mode polymer chains (N>1).
• Internal friction introduces a stiffness-dependent dissipative response in polymer chains.
• Accurate modeling of polymer dissipation requires considering chain complexity and external pulling conditions.