Preparation, Characterization And Application Of PDMS-based Magnetic Response Thin Films

Organic-inorganic nanocomposites have become a hotspot in materials science, and have potential applications in many fields that include electronics, optics and mechanics.Organic-inorganic nanocomposites are roughly divided into non-responsive organic-inorganic nanocomposites and stimuli-responsive organic-inorganic nanocomposites.Some organic-inorganic nanocomposites under external stimuli can produce reversible performance changes, such as photochromism. We study a lot of literature. Related research for the magnetic response of organic-inorganic nanocomposites films is still very less.We fabricated a series of organic-inorganic nanocomposites with magnetic response.In the first part, the Fe3O4 nanoparticles with diameter of 20 nm were incorporated into PDMS to fabricate PDMS-Fe3O4 nanocomposites film with three different types include isotropic, chain anisotropic and short stick anisotropic samples. The optical transmittance of the anisotropic nanocomposites film is higher than that of the isotropic nanocomposites.At the same Fe3O4 nanoparticles weight fractions, the optical transmittance of the short stick anisotropic nanocomposites film is higher than other two films, and the difference is increasing with the increase of Fe3O4 nanoparticles weight fractions. In the case of high Fe3O4 nanoparticle content, we can prepare PDMS-Fe3O4 magnetically responsive optical film with high transparency and good magnetic response. PDMS-Fe3O4 magnetically responsive optical film under the action of external magnetic field can produce strain. We have theoretically analyzed that the application of external magnetic field can affect the refractive index of PDMS-Fe3O4 magnetically responsive optical films.In the second part, Ni and Fe with the same diameter of 50 nm were incorporated into PDMS to fabricate PDMS-Ni magnetically responsive optical films and PDMS-Fe magnetically responsive optical films. Each of them has three different types include isotropic, chain anisotropic and short stick anisotropic samples. Due to the different permeability of the particles, the microstructure of the PDMS-based magnetically responsive optical film is different in the preparation process. The PDMS-based magnetically responsive films prepared with Ni and Fe particles can produce strain under the action of the magnetic field. We theoretically analyzed different kinds of particles may have different effects on the refractive index of the PDMS-based magnetically responsive optical films.PDMS is often used to fabricate microstructure, such as sinusoidal microstructures,microlens arrays, and so on. But they are through the mechanical drive to produce microstructure deformation, and they often are easy wear. The sinusoidal microstructures were fabricated on the surface of PDMS-based magnetically responsive optical films.With the increase of UV ozone treatment time and Fe3O4 nanoparticle content, the period and amplitude of the sinusoidal microstructure increases gradually. The films can produce strain under the action of magnetic field. We also designed PDMS-Fe304 magnetically responsive film microlens array. We use magnetic drive instead of mechanical drive,expanding the scope of application of this microstructure, such as magnetically controlled optical transmittance, magnetically controlled wetting and so on.