Preparation and characterization of a new magnetic fluid with good low temperature resistance  

作　　者：Shilin Nie Decai Li 

机构地区：[1]✉1 Department of Mechanical Engineering,Tsinghua University,Beijing 100084,China [2]State Key Laboratory of Tribology in advanced equipment,Tsinghua University,Beijing 100084,China

出　　处：《Nano Research》2025年第1期477-486,共10页纳米研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.51735006,51927810,and U1837206);the National Key R&D Program of China(No.2020YFB2006900).

摘　　要：Magnetic fluids are a type of novel functionalmaterial that has emerged over the past two decades, whichhave found applications in various aspects of production anddaily life. However, the application of conventional magneticfluids in low-temperature environments is severely limited andoften unsatisfactory. To address this issue, we havedeveloped a new magnetic fluid with excellent low-temperatureresistance. Initially, bare Fe_(3)O_(4) magnetic nanoparticles(FMNPs) were synthesized via co-precipitation without aprotective gas. Subsequently, these particles were modified using polyethylene glycol (PEG)-4000 as a surfactant. Thebare and modified FMNPs (MFMNPs) were characterized using X-ray diffraction (XRD), vibrating sample magnetometer(VSM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetricanalysis-differential thermal gravimetric (TGA-DTG) analysis. The rheological properties, low-temperature resistance of themagnetic fluid were also evaluated. The characterization results indicate that the MFMNPs are spherical andmonodisperse, with a narrow size distribution and a mean particle size of approximately 12 nm. Furthermore, the FTIRspectra and TGA-DTA results suggest that PEG-4000 is linked to the bare Fe_(3)O_(4) particles via hydrogen bonding, indicatingsuccessful modification of the Fe_(3)O_(4) magnetic nanoparticles using PEG. VSM measurements demonstrate that surfacemodification does not alter the crystal morphology or superparamagnetic of Fe_(3)O_(4). However, it does reduce the saturationmagnetization from 68.17 to 54.75 emu/g. Additionally, the prepared magnetic fluid exhibits shear thinning and magneticviscosity effects. It also exhibits excellent low-temperature resistance, maintaining good fluidity without freezing even at -60 ℃. In summary, these results collectively indicate that the new low-temperature resistant magnetic fluid developed in thisstudy is stable and has broad application prospects.

关 键 词：magnetic fluid low-temperature resistance polyethylene glycol ethylene glycol aqueous solution SUPERPARAMAGNETIC 

分 类 号：TB34[一般工业技术—材料科学与工程]