Application of Ionic Liquid as Surface Modifier :

Switching Behavior of Novel Fluoroalkyl End-capped Vinytrimethoxysilane Oligomer —Tri-n-butyl-[(3-trimethoxysilyl)propyl]phosphonium Chloride Silica Nanocomposites between Superhydrophilicity and Oleophobicity

Abstract

New fluoroalkyl end-capped vinyltrimethoxysilane oligomer - ionic liquid silica nanocomposites were prepared by sol-gel reaction of the corresponding oligomer in the presence of phosphorus-type ionic liquid : tri-n-butyl-[3-(trimethoxysilyl)propyl]phosphonium chloride under alkaline conditions. These fluorinated nanocomposites were found to apply to the surface modification of glass, and the modified glass surface exhibited a high oleophobicity imparted by fluoroalkyl groups in nanocomposites. Interestingly, this modified glass surface was found to show superhydrophilicity derived from hydrophilic cationic ionic liquid segments through the flip-flop motion between fluoroalkyl groups and the ionic liquid segments in nancomposites when the surface environment is changed from air to water.