The Research Of Multiple Fluid Micro Hybrid In Microfluidic Chip

Microfluidic chip, is a major basic characteristics of fluid flow in micrometer scale science and technology in the world which has a15-year study of the course of development. There are a lot of problems in the microfluidic chip, the most obvious difficult problem is the microeconomic conditions. A large number of experiments showed that for the microscale mixing a variety of fluid mixing under reaction system when the reaction rate is greater than the mixing speed, mixing time required to become a decisive factor for the decision of the completion of the reaction time, and if the mixing is carried out is not complete, then the reaction may not be sufficiently completed. However, within the microscopic field, the Reynolds number of the fluid is very low (typically<1), the movement of the fluid within the channel in a laminar flow-based, basically does not generate turbulence, the mixing is mainly rely on the free diffusion of molecules, this is very difficult to achieve rapid efficient mixing in only a few square centimeters chip. Microscale fluid mixing difficulties seriously hampered the large-scale application of this new detection analytical tools, urgent research necessary measures to enhance the mixing.According to the above problem,the solution is by pyrolysis prepared performance Fe3O4magnetic nanoparticles and mixed with the reaction solvent, configure a stable magnetic fluid. Subsequently, the magnetic fluid is introduced into the microfluidic chip layer between the fluid flow state to undermine the role of the magnetic fluid force, the use of an external magnetic field, and thus achieve the purpose of the fast, efficient mixing of multiple fluids.Specifically study the role of the external magnetic field enhanced mixing effect. As active micromixer form one of the outer magnetic field, mainly by means of the energy input of the magnetic force, in order to enhance the flow field in the micro-channel excitation diffusion between fluid molecules, thereby improving the fluid mixing uniformity. The external magnetic field is bound as a magnetic micro stirrer only the drive energy sources, is bound to play a vital role in the stirring effect of magnetic micro stirrer. From two aspects:a)Magnetic field strength of the mixing effect. The different magnetic field strength directly affects the force on the magnetic nanoparticles of the role in the passage, and has an important role in movement between the liquid. Too strong magnetic field, the nanoparticles will soon be adsorbed onto the side close to the pole, caused mixed ineffective. Weak magnetic field, the nanoparticles is difficult to overcome the movement of the solution of the viscous force equally ineffective. Therefore, it is necessary to optimize the magnetic field strength.b)The impact of the different forms of the mixing effect of the magnetic field. The operability of the magnetic field, we can provide a different form of the magnetic field for the magnetic micromixer as the excitation source. Such as the use of the permanent magnet providing a constant magnetic field; electromagnet used to provide a sinusoidal alternating magnetic field; cleverly designed driving means, can also provide the rotating magnetic field to drive the micromixer. The different ways of driving under the trajectory of the nano-particles is varied, to promote fluid mixing mechanism will be different. It can be predicted, its the mixed effect will have a larger difference. Therefore, it is necessary to conduct in-depth research.