Shaping polymersomes into predictable morphologies via out-of-equilibrium self-assembly

Area of Science:

• Materials Science
• Nanotechnology
• Physical Chemistry

Background:

• Polymersomes are self-assembled bilayer vesicles from amphiphilic block copolymers.
• These nanocapsules offer tunable properties like flexibility, permeability, and size.
• A key limitation has been the lack of methods to control polymersome shape.

Purpose of the Study:

• To establish a precise and mechanistically understood method for controlling polymersome shape.
• To explore the shape transformation process and its underlying physical principles.
• To provide design rules for achieving diverse polymersome morphologies.

Main Methods:

• Utilizing an out-of-equilibrium process involving controlled osmotic pressure and permeability.
• Inducing controlled deflation and subsequent reinflation of polymersomes.
• Employing magnetic birefringence to probe transient shapes and quantitative electron microscopy for morphology analysis.

Main Results:

• Demonstrated precise control over polymersome shape transformation.
• Observed a hysteretic deflation-inflation trajectory, consistent with bending energy models.
• Successfully accessed intermediate shapes and provided a phase diagram for shape control.

Conclusions:

• The developed procedure offers unprecedented control over polymersome morphology.
• The findings provide a mechanistic understanding of shape transformation driven by bending energy.
• This work lays the foundation for designing polymersomes with specific, predictable shapes for various applications.