The stretching force on a tethered polymer in pressure-driven flow

Area of Science:

• Polymer physics
• Fluid dynamics
• Computational biophysics

Background:

• Understanding polymer behavior in confined geometries is crucial for microfluidic and nanofluidic applications.
• Tethered polymer stretching is influenced by fluid flow and channel dimensions.

Purpose of the Study:

• To investigate the stretching dynamics of a single tethered polymer in micro- and nanochannels.
• To establish a relationship between fluid flow properties and the stretching force on the polymer chain.
• To compare simulation results with experimental data for tethered DNA.

Main Methods:

• Mesoscopic lattice-Boltzmann/molecular dynamics simulations were employed.
• Analytical expressions for stretching force were derived and validated.
• Langevin dynamics simulations were used to confirm findings.
• Microfluidic stretching experiments of tethered λ-DNA provided comparative data.

Main Results:

• A proposed analytical expression for stretching force shows linear dependence on monomer count and boundary shear rate.
• Hydrodynamic interactions were found to have negligible influence on polymer stretching.
• Simulation data accurately predict fractional polymer chain extension.
• Weak Poiseuille flow profiles effectively align polymer chains along channel walls.

Conclusions:

• The study provides a validated analytical model for tethered polymer stretching in micro/nanochannels.
• Simulation results align well with experimental observations of DNA stretching.
• Findings offer insights into polymer behavior under flow in confined environments.