Shapes of vesicles encapsulating two aqueous phases.

Area of Science:

• Soft matter physics
• Biophysics
• Polymer science

Background:

• Vesicles are crucial in biological systems and nanotechnology.
• Understanding the behavior of multi-phase vesicles is key to controlling their properties.
• Polymer-induced phase separation and shape changes in vesicles are complex phenomena.

Purpose of the Study:

• To theoretically investigate vesicles containing two aqueous polymer phases.
• To analyze the impact of polymer concentration and membrane interactions on vesicle shape.
• To map the morphological phase diagrams of these complex vesicles.

Main Methods:

• Utilized Helfrich curvature elasticity theory for fluid membranes.
• Employed self-consistent field theory for polymer behavior.
• Calculated spatial polymer distributions and vesicle shapes.

Main Results:

• Achieved stable vesicle shapes with two distinct polymer phases.
• Demonstrated that reduced polymer conformational entropy influences vesicle shape.
• Identified shifts in phase boundaries (oblate-prolate, oblate-stomatocyte) with altered reduced volume.
• Observed oblates occupying a larger reduced volume range compared to neat vesicles.

Conclusions:

• Polymer properties and membrane interactions significantly dictate vesicle morphology.
• Inhomogeneous entropic pressures arising from polymer confinement drive shape transformations.
• Morphological phase diagrams provide insights into vesicle behavior under varying conditions.