Solvent effect on equilibrium organization of confined polymers

Area of Science:

• Polymer Physics
• Statistical Mechanics
• Biophysics

Background:

• Investigating polymer organization in confinement is crucial for understanding cellular processes like chromosome separation.
• The role of solvent quality in polymer separation and domain formation within confinement remains unclear.
• Previous models explored polymer interactions but lacked detailed analysis of confinement geometry and solvent effects.

Purpose of the Study:

• To investigate the structural transitions and organization of two polymers in symmetric (box-like) and asymmetric (triangle-like) confinement.
• To understand how solvent quality influences polymer separation and globule formation under different confinement geometries.
• To determine the effect of confinement shape on the free-energy barrier for polymer separation.

Main Methods:

• Utilizing the exact enumeration method for a two-dimensional self-avoiding walk model of polymers.
• Analyzing structural transitions, polymer size, and free-energy barriers.
• Comparing polymer behavior in equal-area box-like and triangle-like confinement.

Main Results:

• Polymers show a stronger tendency to form individual globules in triangular confinement compared to box-like confinement.
• A non-monotonic change in polymer size and variations in the free-energy barrier were observed.
• Asymmetric confinement was found to effectively trap polymers in poor solvents due to a significant free-energy barrier.

Conclusions:

• Confinement geometry significantly impacts polymer organization, favoring individual globule formation in asymmetric (triangular) shapes.
• Asymmetric confinement offers a mechanism to control polymer phase separation and stability, particularly in poor solvents.
• This research provides insights into polymer behavior relevant to biological systems and materials science.