Study On The Properties Of Ionic Liquids Used For The Liquid Lens

Comparing to conventional glass and plastic lens,liquid lens based on the focusing principle of the human eye,has the advantage of small size,fast response,low power consumption,long life and high precision,etc..It has great potential application in digital cameras,cell phones,cameras,endoscopes and other optical systems.Unlike lens with aqueous solution,liquid lens containing ionic liquid can be applied not only in extremely high or low temperature environment,but also in the near infrared region.Liquid lens containing Ionic liquid has broad application prospects.In this paper,the refractive indices of miscible part of the binary systems 1-ethyl-3-methylimidazolium acetate([EMIM][OAC])+ methyl benzoate(MB)and [EMIM][OAC]+ dimethyl carbonate(DMC)at different temperatures and mass fractions of [EMIM][OAC] were measured,and correlated by a linear equation.The correlation results agree well with experimental results,and it provides a convenient way to get concentrations from refractive indices.The surface tensions of [EMIM][OAC],MB and DMC at different temperatures were measured.Liquid-liquid equilibria of the two binary systems([EMIM][OAC] +MB and [EMIM][OAC]+DMC)and refractive indices of the equilibrated phase were measured.The results show that liquid lens prepared by the system of [EMIM][OAC]+DMC is convex lens,and it is more stable than the system of [EMIM][OAC]+MB in the studied temperature range.The solubility of aromatic compounds in ionic liquids are weakly dependent on the temperature.However,the application of the system of [EMIM][OAC]+MB in liquid lens needs further investigation.A group contribution method was proposed to predict the refractive indices of ionic liquids at different temperatures.1161 data points of refractive indices(?=589nm)of 115 ionic liquids including 5 kinds of cations and 26 kinds of anions were collected from literature,and 39 groups were obtained by a new group dividing method.The contribution values of 39 groups were obtained by correlation of the collected data of refractive indices.The standard deviation and the average relative deviation the correlation are 0.00897 and 0.452%,respectively.The contribution method was verfied by two ILs which are not involved in the collected data.The relative deviations of the predictions and experimental results are 0.520% and 0.284%,respectively.