Synthesis, Characterization And Properties Of Fe (Ni)/PAA Composite Films With Structural Color

To develop new green anti-counterfeiting materials, a great deal of interest has arisen in the multi-functional materials with structural color. Especially, the effective PAA template combined with electrochemical deposition to prepare anti-counterfeiting materials has attracted great interest, due to its simple equipment and low cost. Based on the above considerations, we have fabricated PAA/A1film deposited with ferromagnetic materials, and characterized the microstructure、crystallography、optical properties and magnetic properties by SEM、XRD、UV-VIS、PPMS and digital camera to discuss in detail. The results are as follows:1. Using once anodic oxidation method, PAA/A1films were prepared in45g/L phosphoric acid at room temperature and0.3mol/L sulfuric acid electrolyte at5℃, respectively. The samples show structural color in the visiable light range. Compared with the oxidized once PAA/A1films in the sulfuric acid, the color saturation of those in phosphoric acid electrolyte is higher. We analyzed that such quasi-ordered microstructure characteristics of the phosphoric acid PAA film might scatter the light reflected from the alumina/Al interface more effectively than the relatively regular arrays in the sulfuric acid PAA, thereby leading to more highly saturated color. Also the barrier layer of PAA/A1film prepared in sulfuric acid electrolyte is thinner and easier for ac elctrodeposition.2. The phosphoric acid Fe/PAA nanocomposite films with good structural color and magnetic properties were synthesized. The observed color is consistent with UV-VIS reflectance spectrum measurement results. The calculated values of λ according to the Bragg-Snell formula are in good agreement with the experimental results. Magnetic measurements at room temperature reveal that the magnetic properties of the nanocomposite films with different anodization times show no magnetic anisotropy and the magnetic mechanism is consist with coherent rotation. This is attributed to the nanowires embedded into the spatially disordered pores of PAA the template.3. The structural colors of phosphoric acid Ni/PAA nanocomposite vary with increasing the thickness of PAA films. The observed color is consistent with UV-VIS reflectance spectrum measurement results. Magnetic measurements at room temperature reveal that the magnetic properties of the nanocomposite films with different colors show no magnetic anisotropy. This attributed to the competition between magnetocrystalline, shape, and stress anisotropies with reference to the applied magnetic field, which leads to the orientation of the fan-shaped distribution of the magnetic moments both along parallel and perpendicular to the Ni nanowires. The magnetic mechanism is consist with coherent rotation.4. The sulfuric acid Fe/PAA nanocomposite films with good structural color and magnetic properties were synthesized. SEM imagine shows Fe was deposited on the PAA membrane surface. This is due to the good electrical conductivity of the PAA film. The observed color is consistent with UV-VIS reflectance spectrum measurement results. Magnetic measurements at room temperature reveal that easy axis of magnetization is perpendicular to membrane surface direction, coercivity reaches2400Oe, magnetic mechanism is consist with coherent rotation.5. The sulfuric acid Ni/PAA films show vivid structural color and magnetic properties. SEM imagine shows Ni was deposited on the PAA membrane surface. The calculated values of X according to the Bragg-Snell formula are in good agreement with the UV-VIS measurement results. Magnetic measurements at room temperature reveal that easy axis of magnetization is perpendicular to membrane surface direction, coercivity reaches940Oe, magnetic mechanism is consist with coherent rotation.6. The predetermined pattern was obtained on the PAA/A1template by an organics-assisted process. With ac electrodeposition method multicolor patterns were obtained. Such colorful films with patterns can be used in many areas, including decoration, display and multifunctional anti-counterfeiting.