Study On SiO₂-based Amorphous Photonic Crystal Structural Colored Materials

In recent years,amorphous photonic crystal materials have attracted extensive attention,not only because of the particularity of its internal structure,but also because of the color characteristics of amorphous photonic crystal materials.Amorphous photonic crystal materials have short-range ordered and long-range disordered structures.When the angle of the incident light changes,the photonic band gap inside the amorphous photonic crystal does not change accordingly,leading to the structure color that does not change with angle of the incident light,namely the so-called non-iridescent effect,which gives people a better visual experience.Therefore,it has a broad development prospect in many application fields such as functional coatings and photoelectric devices.The main contents of this paper include:?1?We get inspiration from organisms with amorphous photonic crystal structure?APSs?,acetylene black powder as black additive,by using blending method to add a certain amount of acetylene black to SiO₂ nanospheres,and dry under a constant temperature to get structural colored pigments of different color.By adjusting the diameter of SiO₂ microspheres,the structural colored pigments can be blue,green or zinzolin.Through SEM analysis,it was found that SiO₂microspheres were in a state of disorderly accumulation in the film,and acetylene black particles existed in the system in the form of agglomeration.The structural colored pigment can also be prepared into colored block or film of APSs by the centrifugal self-assembly or spraying method.Through the analysis of optical photographs,it can be seen that acetylene black particles contribute to the improvement of color saturation and have no influence on the hue.Meanwhile,the color of the structure does not change with the change of observation angle.?2?PPy particles can also be used as an alternative material to enhance the structural color of films,and the application of structural color on ceramic surfaces is rarely involved.Therefore,the low-temperature polymerization was used to synthesize PPy microspheres,and then SiO₂ nanosphres and PPy particles were blended to prepare ethanol suspension solution,and different colored films of APSs were prepared on the surface of ceramic substrate by means of the drop coating.Surprisingly,the structural colored films prepared under direct light conditions will show metallic luster.By regulating the size of SiO₂ nanospheres and the composition ratio of SiO₂ and PPy particles in detail,we also obtained the color plate diagram of APSs.This provides a basis for the application of structure color of APSs in coatings,food additives and color display in the future.?3?In order to increase the stability of black additives in amorphous materials,we prepared a structural colored pigment by using the core-shell structure of SiO₂ supported PPy black material.By in-situ polymerization of pyrrole on the surface of SiO₂ monodisperse,a thin layer of black particles is formed.By adjusting the diameter of SiO₂ spheres,the structural colored pigments can show green,red or purple.However,the amount of Py monomer can affect the particle morphology.In subsequent studies,we determined that the ratio of SiO₂ to pyrrole monomer was 0.25 g:15?l.The core-shell structure can also be used to form a bright and low-angle dependent structural colored films on the surface of the glass substrate by a simple and controllable spraying method.Optical characterization results showed that the preparation of structural colors with high color contrast could be attributed to the absorption of light by PPy particles on the surface of SiO₂ nanospheres.Compared with the original assembly of SiO₂,the color of SiO₂@PPy amorphous photonic crystal film changed,which may be because the coating of PPy increased the particle size and gave SiO₂@PPy microspheres lower refractive index.?4?In many industrial applications,structural color materials are required to have the characteristics of high binding force and mechanical strength,in order to improve the stability of structural color materials under external stimulation.Here,the colored films of SiO₂@PPy with different colors was used as the template.Then polyvinyl alcohol?PVA?was repeatedly filled on the surface of the film.After several minutes,the excess PVA solution was removed.Through the optical test,it is found that the film can maintain a low-angle dependence and has high adhesion and mechanical strength,and its reflection peak of the structural color on the glass substrate has a slight blue shift,but does not affect the color display.This phenomenon is of great significance to the application of structural color materials in practical production and life.