Easy and versatile functionalization of lithium niobate wafers by hydrophobic trichlorosilanes

The functionalization of lithium niobate surface has been successfully obtained by the grafting of trichloro-organosilane derivatives thanks to liquid phase silanization or micro-contact printing. This functionalization has been proved by X-ray photoelectron spectroscopy and Fourier transform infrared spectroscopy. The data show that the stability of the self-assembled monolayer (SAM) film on the trichloro(1H,1H,2H,2H-perfluorooctyl)silane-modified lithium niobate surface is largely due to the formation of a siloxy-niobate (–Si–O–Nb–) bond via a condensation reaction between –Si–Cl and niobate hydroxide (–NbOH). The extremely hydrophobic and stable SAM on lithium niobate could have useful applications in acoustic droplet handling and more generally surface acoustic waves (SAW) device preparation for lab-on-chip devices.