Fluctuations and Shape Dependence of Microphase Separation in Systems with Long-Range Interactions.

Area of Science:

• Soft Matter Physics
• Physical Chemistry
• Materials Science

Background:

• Phase separation is a fundamental process in various materials and biological systems.
• Long-ranged interactions, such as effective Coulomb forces, significantly influence self-assembly.
• Understanding microdomain formation is crucial for controlling material properties and biological functions.

Purpose of the Study:

• To investigate the phenomenon of microphase separation driven by Coulomb interactions.
• To predict the sizes and shapes of microdomains and their dependence on macroscopic sample geometry.
• To explore the applicability of the Coulomb theory to both equilibrium and nonequilibrium systems.

Main Methods:

• Theoretical modeling combining phase separation principles with effective Coulomb interactions.
• Derivation of predictions for microdomain characteristics.
• Application of the theory to equilibrium salt solutions and block copolymers.
• Mapping of nonequilibrium phase separation, including cellular condensates, to the Coulomb theory framework.

Main Results:

• Microphase separation is driven by the interplay of phase separation and Coulomb interactions.
• The macroscopic sample shape critically influences microdomain sizes, shapes, and interfacial tension.
• The effective interfacial tension of fluctuations in the lamellar phase is dependent on sample geometry.
• The Coulomb theory framework successfully describes both equilibrium and nonequilibrium phase separation phenomena.

Conclusions:

• The study provides a theoretical framework for predicting microphase separation behavior.
• Macroscopic sample shape is a key parameter in controlling microdomain morphology and interfacial properties.
• The findings have broad applicability, including to biological systems like cellular condensates.
• The effective interfacial tension can be significantly reduced, potentially leading to ultralow values.