Surface-induced phase transitions of wormlike chains in slit confinement

Area of Science:

• Polymer Physics
• Soft Matter Science
• Statistical Mechanics

Background:

• Understanding polymer behavior under confinement is crucial for materials science and nanotechnology.
• Semi-flexible polymers exhibit complex structures influenced by chain stiffness and intermolecular interactions.
• Previous models often simplify polymer flexibility or confinement geometry.

Purpose of the Study:

• To investigate the influence of chain flexibility on the structural organization of semi-flexible polymers.
• To analyze polymer behavior confined between two parallel walls using a theoretical framework.
• To identify distinct structural phases and transitions driven by density changes.

Main Methods:

• Employed a self-consistent field theory (SCFT) for semi-flexible polymer chains.
• Utilized a wormlike chain formalism to model flexibility from rod-like to flexible limits.
• Incorporated Onsager-type interactions to account for orientation-dependent excluded-volume effects.

Main Results:

• Identified three distinct surface states: uniaxial, biaxial, and condensed.
• Numerical solutions revealed the conditions under which these states emerge.
• Demonstrated that increasing overall density can induce first-order phase transitions between these states.

Conclusions:

• Chain flexibility is a key determinant of polymer structure in confined geometries.
• The SCFT model successfully predicts multiple ordered phases and transitions in lyotropic systems.
• This work provides theoretical insights into the phase behavior of confined semi-flexible polymers.