Chapter 12. Creation of Superamphiphobic, Superhydrophobic/Superoleophilic and Superhydrophilic/Superoleophobic Surfaces by Using Fluoroalkyl-endcapped Vinyltrimethoxysilane Oligomer as a Key Intermediate

Abstract

Fluoroalkyl-endcapped vinyltrimethoxysilane oligomers {RF–[CH2CHSi(OMe)3]n–RF; RF=CF(CF3)OC3F7, n=2, 3: RF–(VM)n–RF oligomers} were applied to the fabrication of superamphiphobic (superoleophobic/superhydrophobic), superoleophobic/superhydrophilic and superoleophilic/superhydrophobic surfaces. RF–(VM)n–RF oligomeric silica nanoparticles [RF–(VM–SiO2)n–RF], prepared by sol–gel reactions of the corresponding oligomers under alkaline conditions, supply the superhydrophobic/oleophobic surface. However, the superamphiphobic surface can be easily fabricated by using RF–(VM)n–RF oligomeric silica nanocomposite-encapsulated biphenylene units [RF–(VM–SiO2)n–RF/Ar-SiO2], which were prepared by sol–gel reactions of the corresponding oligomer and a biphenylene unit-containing silane coupling agent [Ar-Si(OEt)3] under alkaline conditions. The encapsulation of calcium silicide particles into the RF–(VM)n–RF oligomeric silica nanocomposite cores affords the superoleophobic/superhydrophilic surface. In contrast, interestingly, the encapsulation of micrometer-sized controlled crosslinked polystyrene particles into the RF–(VM)n–RF oligomeric silica/talc nanocomposite cores can provide the superoleophilic/superhydrophobic surface, and the composite particle powders obtained are applicable as packing materials for the column chromatography to separate the water/oil emulsions stabilized by surfactants.