Abnormal polymer transport in crowded attractive micropost arrays

Area of Science:

• Soft Matter Physics
• Polymer Science
• Computational Physics

Background:

• Understanding polymer dynamics is crucial in various fields, including materials science and nanotechnology.
• Confining polymers to quasi-two-dimensional environments introduces unique transport phenomena.
• The influence of attractive obstacles on polymer diffusion requires detailed investigation.

Purpose of the Study:

• To investigate the diffusion of polymers in a quasi-two-dimensional environment with attractive cylindrical posts.
• To elucidate the non-monotonic relationship between polymer diffusivity and post array density.
• To understand the role of adsorption-desorption transitions and critical adsorption strength in polymer dynamics.

Main Methods:

• Langevin dynamics simulations were employed to model polymer diffusion.
• The system consisted of polymers in a quasi-two-dimensional space with attractive cylindrical posts.
• Key parameters investigated included post array density, adsorption strength, and polymer chain length.

Main Results:

• Polymer diffusivity exhibits non-monotonic dependence on post array density.
• Below critical adsorption strength (ε < ε_c), diffusivity decreases with increasing post density due to reduced void volume.
• Above critical adsorption strength (ε > ε_c), diffusivity can increase with post density, reaching a maximum.
• This increase is attributed to cross-post translation facilitated by polymer conformation fluctuations.

Conclusions:

• Polymer diffusion in confined attractive environments is complex and highly dependent on adsorption phenomena.
• The interplay between polymer conformation, adsorption strength, and obstacle density dictates transport mechanisms.
• Findings provide insights into designing materials with controlled polymer transport properties.