Relaxation of surface-tethered polymers under moderate confinement

Area of Science:

• Polymer physics
• Fluid dynamics
• Biophysics

Background:

• Surface-tethered polymers exhibit unique dynamics influenced by confinement.
• Understanding polymer relaxation is crucial for microfluidic applications and biological processes.

Purpose of the Study:

• To investigate the relaxation dynamics of surface-tethered polymers in microchannels under moderate confinement.
• To determine the scaling behavior and dominant mechanisms governing polymer relaxation.
• To establish an experimental correlation for relaxation time based on molecular and channel dimensions.

Main Methods:

• Experiments using fluorescence-marked DNA molecules.
• Coupled lattice-Boltzmann and molecular dynamics simulations.
• Analysis of scaling exponents and relaxation times.

Main Results:

• Polymer relaxation is dominated by Zimm-dynamics with significant intra-chain hydrodynamic interactions.
• Relaxation time increases with decreasing channel height, indicating a pronounced confinement effect.
• An experimental correlation for the longest relaxation time was derived.

Conclusions:

• Moderate confinement significantly impacts polymer relaxation dynamics in microchannels.
• The findings provide a quantitative understanding of polymer behavior in confined environments.
• Good agreement between experimental and simulation results validates the study's approach.