Study On Magneto-induced Refractive Index And Magneto-induced Stress Of PDMS-based Magnetic Nanocomposite Films

Among the numerous nanocomposite materials,magnetorheological elastomer(MRE)has received extensive attention due to its excellent properties.At present,there have been a large number of researches on the properties and applications of macro-sized MRE materials,but there are few studies on the optical and mechanical properties of MRE materials in the microscopic field,experiments and simulations are combined to study the mechanism of the change of the magnetically induced refractive index of the MRE thin film,which will prepare for the further study of the magnetically responsive microlenses in the future.Taking the PDMS-based nanocomposite film as the research object,the change of the magneto-induced stress of the MRE film at a higher mass fraction is explored,which will provide help for the future research on friction properties and the application of micro-scale robots.The main research contents of this paper :(1)According to the literature research and the existing preparation process,three different film fabrication methods were designed,three Fe₃O₄-PDMS nanocomposite optical films with different agglomerated particle sizes were prepared,and the optical properties of the three films were theoretically analyzed.The measurement principle of the ellipsometer is introduced in detail,and the measurement method of the refractive index of the film is studied in this paper.The refractive index measurement experiment of three films is carried out..(2)The second Fe₃O₄-PDMS nanocomposite optical film with five different mass fractions was fabricated,and the refractive index of Fe₃O₄-PDMS nanocomposite optical films with different mass fractions was measured in the absence of a magnetic field,and the nanoparticle mass was analyzed according to the measurement results.The effect of the fraction on the refractive index of the film.The content of nanoparticles in the second phase was found to determine the refractive index of the film.According to the overall structure of the ellipsometer,a magnetic field application device that can generate four different magnetic field strengths is designed.The magneto-induced refractive index of Fe₃O₄-PDMS nanocomposite optical films with different mass fractions was measured under different magnetic field strengths.According to the measurement results,it was found that the magnetic field strength has a significant effect on the refractive index of the film,which mainly comes from the magnetic permeability.The interaction of rate and magneto-induced stress.The magneto-induced stress of Fe₃O₄-PDMS nanocomposite optical films under different magnetic fields was simulated to verify the analysis results.(3)The magneto-induced stress simulation of Fe-PDMS and Fe₃O₄-PDMS films with nine different mass fractions is carried out.Comparing the magnetic induced stress results obtained by the simulation with the existing experimental results,the two are basically consistent.The results show that the magnetic stress of the film is related to the size and number of the agglomerated particles in the film.