离子液体电毛细特性及微流控环境分析原理

As a green extractor ionic liquids have been extensively studied in extraction area，the attention is given in electrowetting area, and discretizatized droplet control technology in the air medium has made progress. But so far, no paper was found on electrocapillary dynamics of ionic liquid in the aqueous solutions，that believed great applicapability on the microfluidic fluidics. The difference of solubility between positively and negatively charged components of the hydrophobic ionic liquids is the reason of electric double layer formation in aqueous solutions. Meanwhile, the electrowetting and electrocapillary properties of ionic liquid is not only affected by variable electrolyte composition in solution，but also by different charge and hydrophobicity of the extracted compounds when extraction carried out. This contribution to the electric double layer and effects on electricwetting and electrocapillary properties of ionic liquids is not clear. This project intends to adopt a range of hydrophobic ionic liquids and different charges or hydropobicities compounds as extraction materials, by means of physical, physical and chemical, and chemical analysis methods to solve the above problems. The main contents of study as follows: 1) Electrowetting-on-dielectric properties(EWOD). EWOD of the hydrophobic ionic liquids in pure and extracted forms will be studied by contact angle measurement under different electrolyte solutions. The compounds used for extraction includes variable cationic and anionic and neutral compounds with different hydrophobicity so that comprehensively evaluate the contrinution of different types of compounds to the electrowetting properties of ionic liquids; 2) Electrocapillarity. Electrocapillarity of the pure and extracted states of ionic liquids will be studied by electrochemical method with four-electrode system, and the effects of extraced compounds on point of zero charge will be investigated; 3) Dynamic electrocapillary characteristic. Dynamic electrocapillary properties will be investigated by traditional Lipmann divice, and dynamic properties of electrocapillary pressure, velocity and hysterisis of pure and extracted forms will be investigated in varable electrolyte; 4) Influence of electroosmotic flow on electrocapillary properties. Owing to electric double layer generation in aqueous solutions, ionic liquid motion could be controllable in channels by electroosmotic flow.The working principle of the ionic liquids motion under electroosmotic flow will be investigated as function of applied voltage, droplet size, pH of elecrolytes and electroosmotic direction;5) Based on the electrocapillary and electrowetting phenomenon of ionic liquid in water- ionic liquid immiscible two phase system, study novel nL-droplet sample extraction,droplet transfering and injection,fusion and separation methods. There is hope that the research play in principle role in developing novel microfluidic environment pollutants monitoring methods.

研究离子液体电毛细特性是解决介电湿润方法水滴蒸发问题的关键技术。疏水性离子液体在水溶液中因部分正负电荷组分溶解不平衡导致其两相界面形成双电层，体现电毛细特性。在此离子液体的正负电荷组分的溶解度起主要作用，但当发生化学萃取后，被萃取物的电荷性质、疏水性以及水相电解质成分对其在溶液中形成双电层的贡献程度和如何影响电湿润及电毛细性质还不清楚。项目拟采用不同疏水性离子液体为材料，借助于物理、物理化学及常规化学分析方法，对纯净疏水性离子液体在不同电解质溶液环境中的介质上电湿润静态特性及电毛细作用的动态特性进行测定，对离子液体在萃取具有不同电荷及疏水性化学物后的电湿润特性进行研究，对微流控通道中表面电渗流对其电毛细动态特性进行研究，并对疏水性离子液体与水溶液构成的两相微全分析原理进行探究，为进一步利用疏水性离子液体的介质上电湿润及电毛细特性，开发环境污染化合物监测方法的有关研究提供原理方面的基础资料。

研究离子液体电毛细特性是解决介电湿润方法水滴蒸发问题的关键技术。疏水性离子液体在水溶液中因部分正负电荷组分溶解不平衡导致其两相界面形成双电层，体现电毛细特性。当发生不同化学萃取后，被萃取物的电荷性质、疏水性对其在溶液中如何影响电湿润及电毛细性质对开发微流控环境分析方法有重要意义。针对这些问题，我们采用疏水性离子液体为材料，对疏水性离子液体在发生萃取后的介质上电湿润静态特性及电毛细作用的动态特性进行了测定，对微流控通道中表面电渗流下电毛细动态特性进行了研究，并对疏水性离子液体与水溶液构成的两相微全分析原理进行探究，提出了离子液体电毛细测定方法和扩散限制样品处理-多通道分离的环境污染化合物富集分析一体的新方法，以及芯片分离通道表面亲疏水性改性方法。