Description |
The synthesis and characterization of a series of novel hydrophobic room temperature ion liquids (RTILs) are reported along with their applications in a variety of different systems ranging from electrochemical cells to biphasic separations. The effect of alkyl chain length, anion composition, and the SiO2 surface charge density were examined in 1-alkyl-3-methylimidazolium cations (Cnmim, n = 4, 6, 8, 10, 12) at the RTIL/SiO2 interface using sum frequency vibrational spectroscopy (SFVS). These studies concluded that the orientation of the 1-alkyl-3-methylimidazolium cation was dictated largely by the length of the alkyl chain. As the alkyl chain length increased, the number of gauche defects in the chain decreased, and the imidazolium ring orientation becomes more perpendicular to the SiO2 surface. Changes in the surface charge density of the SiO2 also affected the orientation of the imidazolium ring. As the surface charge density became more negative the imidazolium ring oriented more parallel to the surface. |