基于系列离子液体的折射率研究

离子液体作为新颖的"软"功能材料已成为目前研究的新热点。折射率的研究对了解离子液体这种新型光学材料的结构性质具有重要意义。对选取的系列离子液体{Cnmim]BF4(n=6,8,10,12),Cnmim]PF6(n=8,10,12),Cnmim]I(n=7,8,10),Cnmim]Cl(n=10,12,14),CnPy]BF4(n=9,11,13)等}在空气中的折射率进行了测试和理论分析,结果表明,(1)若阴离子为BF4-和PF6-,离子液体的折射率随阳离子侧链的增长而线性增加;若阴离子为Cl-和I-,离子液体的折射率随离子液体阳离子侧链的增长而线性减小,相关系数R分别是0.98854、0.98004、0.99942、-0.97888、-0.9793;(2)当阳离子一定时,阴离子体积越大,折射率越小,单元素阴离子比多元素阴离子的离子液体折射率要大;(3)离子液体的折射率随温度升高而减小,卤盐离子液体与四氟硼酸盐和六氟磷酸盐离子液体相比对温度变化更敏感。

Study on the refractive index of series of ionic liquids

Ionic liquids,as novel "soft" functional materials have become a new hotspot in the research field at present.The research of the refractive index of ionic liquids is important to research structure properties on this new type of optical materials.In this paper,we selected series ionic liquids: BF4(n=6,8,10,12),PF6(n=8,10,12),I(n=7,8,10),Cl(n=10,12,14),BF4(n=9,11,13),tested the index of refraction of ionic liquids in the air and had a theoretical analysis.The results showed that:(1) for anionic BF-4and PF-6,as the growth of cationic side chain the ionic liquids refractive index would linearly increase;if ionic liquids anions are I-and Cl-,the refractive index of ionic liquids would linearly decease with side chain growth.Correlation coefficient R were 0.98854,0.98004,0.99942,0.97888,0.9793;(2) when the volume of anion is larger,the smaller to the refractive index of ionic liquids;(3) with temperature increasing the refractive index of ionic liquid will decrease,and compared to PF-6/BF-4,the I-/Cl-ionic liquids are more sensitive to the temperature change.