Study On Properties Of Magnetic Fluid Modified By Ionic Liquid

Magnetic fluid is a new type of functional material,which has a wide range of applications in chemical,mechanical,biological and other related fields.However,the traditional magnetic fluid carrier fluid is volatile,toxic,and chemically unstable,which restricts its development.In this article,the ionic liquid is used to modify the magnetic fluid,and the performance changes of magnetic nanoparticles before and after the modification and the performance changes of different ionic liquid-based magnetic fluids are analyzed.Firstly,three ionic liquid-based carrier liquids were prepared,namely[Bmim][PF6],[Hmim][PF6],[Omim][PF6];the three carboxyl functionalized ionic liquid surfactants were ILC5-COOH,IL'C9-COOH,ILC9-COOH.Optimize the preparation method of ionic liquid surfactant modified magnetic nanoparticles,analyze the influencing factors of the solution metal cation concentration,reaction temperature,and reaction time during the preparation process,design an orthogonal experiment,and screen out the metal cation ratio as Co2+:Fe2+:Fe3+=1:1:2,the saturation magnetization of the prepared CoFe2O4 magnetic nanoparticles is 56.44 emu/g at the time of reaction at 70? for 60 min.Secondly,the effects of three surfactants on the particle size of modified CoFe2O4 magnetic nanoparticles were studied.the average particle size of particles modified by ILC5-COOH was about 40 nm,and the average particle sizes of particles modified by IL'C9-COOH and ILC9-COOH were about 21 nm and 18 nm respectively.The results of characterization of the particles before and after modification show that the crystal structure of the particles has not changed,and the coating effect is good.The saturation magnetization of the unmodified particles is 56.56 emu/g,and the saturation magnetization of the particles modified by ILC9-COOH is 46.09 emu/g,which are superparamagnetism.ILC9-COOH is the best surfactant.At last,the influence of ionic liquid-based carrier liquid,surfactant and its addition amount on the stability of magnetic fluid under changing magnetic field conditions was studied.the results showed that the nanoparticles modified by ILC9-COOH had good stability in[Hmim][PF6]and[Omim][PF6],and the steric hindrance force was an important factor to maintain the stability of ionic liquid-based magnetic fluid.Magnetic fluids with different mass fractions were prepared,and their magnetic properties and rheological properties were analyzed.the saturation magnetization of 10 wt%[Hmim][PF6]based magnetic fluids and[Omim][PF6]based magnetic fluids were 5.59 emu/g and 5.28 emu/g,respectively,which showed good magnetic response and good shear flow performance at different temperatures,and could meet the requirements of different environments.The ionic liquid-based magnetic fluid prepared in this paper provides a certain experimental and theoretical basis for promoting the application of ionic liquid in magnetic fluid.