Statistics of polymer adsorption under shear flow.

Area of Science:

• Soft Matter Physics
• Polymer Physics
• Computational Biophysics

Background:

• Understanding polymer dynamics under shear flow is crucial in various applications.
• Previous studies often focused on bulk environments or lacked detailed analysis near interfaces.
• Adsorbing interfaces introduce complex boundary conditions affecting polymer behavior.

Purpose of the Study:

• To investigate the steady-state statistics of a polymer chain in three distinct shear environments.
• To analyze the influence of adsorbing interfaces on polymer chain conformation and dynamics.
• To compare simulation results with theoretical models and scaling predictions.

Main Methods:

• Nonequilibrium Brownian dynamics computer simulations were employed.
• Calculated statistical distributions of polymer chain end-to-end distance and orientation.
• Investigated the frequency of periodic tumbling motion under varying shear rates.

Main Results:

• Polymer chain distributions under shear flow mapped onto a finite-extensible-nonlinear-elastic dumbbell model.
• Fitted anisotropic effective spring constants characterized the polymer's response.
• Tumbling motion frequency was found to be sublinear with increasing shear rate across all tested environments.

Conclusions:

• The finite-extensible-nonlinear-elastic dumbbell model effectively describes polymer behavior in these shear environments.
• Scaling predictions from bulk models are consistent with the angular distribution tails.
• The sublinear dependence of tumbling frequency on shear rate extends previous findings for polymers near interfaces.