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 ...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.展开更多
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).
文摘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.
