Phase Behaviors of Giant Surfactants with Different Numbers of Fluorinated Polyhedral Oligomeric Silsesquioxane Heads and One Poly(ethylene oxide) Tail at the Air-Water Interface

Giant surfactants with different numbers of aryltrifluorovinyl ether-functionalized polyhedral oligomeric silsesquioxane (FVPOSS) heads and one poly(ethylene oxide) (PEO) tail, (FVPOSS)(n)-PEO227, are precisely synthesized. The phase behaviors of (FVPOSS)(n)-PEO227 at the air-water interface were investigated through surface pressure measurements (isotherm and hysteresis experiments) and the Brewster angle microscopy. Upon increasing the number of FVPOSS heads, the interfacial behaviors of these giant surfactants greatly change. More phase transitions occur during the compression as the number of FVPOSS heads increased from one to two and three. The evolution of morphologies of Langmuir films and compression-expansion hysteresis curves further illustrate phase transitions at the airwater interface. Furthermore, molecular mechanisms to describe phase transitions of (FVPOSS)(n)-PEO227 at the interface are put forward. This study deepens the understanding of interfacial phase behaviors of special giant surfactants and provides knowledge of nanostructure design and construction at the interface.

Automated summary

This study investigates the phase behaviors of giant surfactants with different numbers of aryltrifluorovinyl ether-functionalized polyhedral oligomeric silsesquioxane (FVPOSS) heads at the air-water interface. The interfacial behaviors greatly change with an increase in the number of FVPOSS heads, showing more phase transitions and morphological evolution. Molecular mechanisms are proposed to explain the phase transitions at the interface.