Higher-order mesoscopic self-assembly of fluorinated surfactants on water surfaces

Abstract

Surfactants containing fluorocarbon chains have been increasingly studied because they self-assemble into a variety of microscopic and mesoscopic domains and tend to form highly ordered patterns at the air/water interface; these patterns are clearly different from those formed by their hydrocarbon analogs. Focusing on the fluorinated surfactants possessing unique physical characteristics, this review describes the relationship between the line tension and dipole interaction, which is the comprehensive principle governing the pattern formation of two-dimensional self-assemblies. This review further discusses several key experimental and analytical techniques that are useful for characterizing the shape, size, correlation, and viscoelasticity of hierarchical self-assemblies on water surfaces. Finally, several biomedical applications, including biomimetic surface coating, multimodal contrast agents in medical diagnostics, and controlled delivery of gases (O₂ and NO) for oxygenation and antimicrobial effects, are introduced to highlight how the unique physicochemical properties of fluorinated self-assemblies can be applied in materials science.