Ionic liquid self-assembled monolayer and ion exchange for surface force control

m .cn Adhesion and lateral force were controlled by the formation of a self-assembled monolayer combined with the surface ion exchange of ionic liquids on a silicon surface. In this study, the functionalized imidazolium ionic liquids were designed and synthesized with the aim of controlling surface force. N-[3-(Trimethoxylsilyl)propyl] ethylenediamine molecules were first self-assembled onto a surface as an anchor layer and then 1-propionic acid-3-methylimidazolium chloride were successfully grafted onto the amino-modified surface. The surface force was changed by surface ion exchange in various anionic solutions. The self-assembly and ion exchange processes were detected by means of attenuated total reflectance-Fourier transform infrared spectrometry and further confirmed by X-ray photoelectron spectra. Adhesion and friction behaviors were systematically investigated by atomic force/friction force microscope. The results indicated that anio s played a great role in determining surface properties. Furthermore, surface adhesion and friction can be possibly quantitatively determined by the counteranions on the surface. Copyright © 2011 John Wiley & Sons, Ltd.