Theoretical Research on Microstructure and Optical Properties of Magnetic Fluid Composed of Rod-Like Shape Nanoparticles

Magnetic fluid is a kind of colloidal suspension comprised of magnetic nanoparticles, surfactant, and carried liquid. The microstructure and optical properties of the magnetic fluid have become the research hotspots in recent years. In this paper, a new molecular dynamics method based on rod-like magnetic nanoparticles was used to simulate the microstructure change of the magnetic fluid over time by applying different magnetic field. The results indicated that the effect of the applied magnetic field played an important role on microstructure change. The concept of duty cycle was used to quantitatively analyze the degree of magnetic nanoparticles chaining along the direction of the applied magnetic field. It was found that when the applied magnetic field increased from 45 to 315 Oe, the duty cycle of the microstructure decreased from 0.192 to 0.068. In addition, Monte Carlo method was used to analyze the transmission spectrum of magnetic fluid film. The transmittance at the wavelength of 1500 nm increased from 0.71 to 0.84 when the applied magnetic field increased from 45 to 225 Oe. These results revealed that the magnetic fluid could be well applied in the optical sensing area in the future.