Study on the polymer diffusion in a media with periodically distributed nano-sized fillers

Area of Science:

• Polymer Physics
• Materials Science
• Computational Chemistry

Background:

• Understanding polymer behavior with fillers is crucial for material design.
• Nano-filler incorporation significantly alters polymer chain dynamics and structure.
• Previous studies explored various filler shapes and interactions, but systematic analysis of periodic fillers is ongoing.

Purpose of the Study:

• To investigate the impact of nano-sized fillers on the equilibrium and dynamical properties of linear polymers.
• To determine the influence of polymer-filler interaction strength and relative size on polymer diffusion.
• To identify critical parameters governing polymer behavior in the presence of periodic fillers.

Main Methods:

• Off-lattice Monte Carlo simulations were employed to model the polymer-filler system.
• Periodic arrangement of fillers with a defined period (d) was implemented.
• Lennard-Jones potential was used to describe polymer-filler interactions, with varying interaction strength (ɛ(pf)).

Main Results:

• Polymer statistical dimensions and diffusion depend on polymer-filler interaction strength (ɛ(pf)) and the ratio of polymer size (R(G0)) to filler spacing (d).
• Normal diffusion (D ~ N(-α)) occurs when 2R(G0) > d, with diffusion exponent α increasing with ɛ(pf).
• In the regime 2R(G0) < d, normal diffusion is observed only for ɛ(pf) < 2; higher values lead to polymer adsorption and cessation of diffusion.

Conclusions:

• A critical polymer-filler interaction strength (ɛ*(pf) = 2) was identified, distinguishing between normal diffusion and adsorption.
• The interplay between filler size, spacing, and interaction strength dictates polymer dynamics.
• This study provides insights into designing polymer nanocomposites with controlled transport properties.