Influence of the Hydrophilic Property of Imidazole Ionic Liquids on Electro-Fluidic Display

Some ionic liquids (ILs) were used to be the conductive liquids of electro-fluidic displays (EFDs) in this paper. The cationic ion of the ionic liquids is 1-Ethyl-3-methylimidazolium,while the anionic ions have varied hydrophilic properties. Also OH group is added to the cationic ion of EMIMBF4 to increase the hydrophilic property of IL molecule further. The physical properties are compared, including the temperature window and viscosity. More importantly, the influence of hydrophilic property of ILs on electrowetting curve, dye extracting, and aperture voltage of EFD were discussed in this study. The results indicate that the contact angle on fluoropolymer without voltage of hydrophilic ILs is higher than the contact angle of hydrophobic IL. On the other hand, the dye extraction ability of hydrophilic IL is lower than hydrophobic IL. As a consequence, hydrophilic IL is more suitable to be conductive liquid of EFD. Furthermore, the switching results of EFD with one hydrophilic IL (EMIMDCA) as conductive liquid show good optoelectronic response properties.