| There are various colors in nature.From the perspective of color,there are mainly two kinds:chemical color,and structural color.Chemical colorants are usually used with high color saturation,but at the same time cause environmental pollution and resource destruction.Compared with chemical coloring,physical coloring method has attracted much attention:structural colors.Because of the high saturation,adjustable color display,and environment friendly,structural color causes widely attention among many researchers.However,in practical application,the self-assembled structure color film has inevitable defects.It is easy to be polluted and adhered by water,oil and solid pollutants,which limit the application of structural color mayerials in outdoor conditions.This dissertation prepared highly monodisperse PS@SiO2、PS@TiO2、hollow Air@C@TiO2 spheres and CdS@Siv2 microspheres.According to changing the self-assembly process of microspheres and carrying out surface treatment of thin films,the performance of low-angle dependent structure color films is improved.The main content of paper is as follows:(1)Monodisperse PS@SiO2 spheres were prepared by a soap free polymerization and a sol-gel method.Mixed with acetylene black(AC),the monodisperse spheres were sprayed and then disordered self-assembled color films with low Angle dependence were obtained.SEM and TEM images showed that the particle size of the microsphere was uniform and the monodispersity was good.The silica shell with special infiltration was coated with a thickness of about 20 nm uniformly.The PS@SiO2/HFTHTMS films were obtained by fluorinating the surface mixed.The microstructure,color saturation and hydrophobic property of the film were studied.And the results show that the microspheres are ordered in short range order and long range disorder.AC is necessary to improve the saturation of the color and absorb backscattered light,also,the structure color does not change in different angles.Water contact angle is 169.5 °(saturated acid,alkali,salt solution of contact Angle>150°),oil contact Angle>90° formed the super hydrophobic and oleophobic double hydrophobic surface,and the film effectively resisting the invasion of liquid and solid particle pollutants.The droplet bounce phenomenon is a good complement to the film’s excellent biphobicity.(2)PS@TiO2 nanospheres with different particle sizes were prepared by a sol-gel method and a mixed solvent method,and then sprayed mixed with C to obtain low-angle dependent structure color films.The surface modification of waterborne polyurethane(WBPU)can improve the mechanical strength of the structure color film and retain the property of underwater oil repellent.SEM,AFM and TEM tests indicated that PS@TiO2 nanospheres had uniform size,good monodispersity and uniform thickness.TiO2 is coated on PS NPs surface with spherical nanoparticles of 8 nm,forming multistage roughness.With the increase of TBOT content,the thickness of PS@TiO2 nanospheres increased.Film analysis shows that:The color in different angle does not change;The film has underwater repulsion to 8 kinds of oil with different surface tension,such as n-hexane,and the contact Angle is>150°;Hydrophobic property under water within PH range 0-14;WBPU increases the adhesion force among PS@TiO2 microspheres,and effectively withstands water column scour and scraping test to improve mechanical properties.(3)PS core structure was removed through the secondary calcining process in order to avoid the problem of pigment aggregation and uneven color distribution caused by the addition of melanin.After the first high temperature calcining and second calcining under low temperature,Air@C@TiO2 hollow sphere was obtained.The effects of calcining time and temperature on the integrity of shell formation were investigated,and the effects of in-situ synthesis of carbon black on the color saturation of Air@C@TiO2 structure were analyzed.SEM and TEM showed that Air@C@TiO2 hollow sphere could be obtained by calcining at 120℃ in air after the first 500℃ calcination,and these TiO2 spherical shell structure is complete.The particle size distribution is narrow,which meets the requirement of amorphous photonic crystals with low angle dependence.Lattice fringe shows that TiO2 is anatase phase.Also,EDS showed that PS nuclear structure in situ synthesized carbon elements attached to the inner wall of TiO2 shell,and TiO2 shell boundary is obvious.PS is used to synthesize in situ carbon black by calcining in nitrogen protection.At the same time,the structure color is dark.After the second calcining and volatilization of carbon,the melanin is reduced to achieve the purpose of desaturation and color formation.(4)With thiourea as the sulfur source,cadmium nitrate tetrhydrate as the cadmium source,and a reduced diethylene glycol as the mild reaction environment,CdS microspheres were prepared by two-step seed solution method and assembled into high refractive index structural colorants without introducing melanin.The content of thiourea and cadmium nitrate,reaction time,temperature and other factors on the growth of microspheres were investigated.The microstructure and color saturation of the self assembled microspheres were analyzed under the condition of vacuum strip drying.XRD and SEM showed that CdS microspheres are of cubic wurtzite structure.Due to their large specific gravity,they exhibit short-range order but long-range disorder in the self-assembly process,and then form a low-angle dependent defect structure.The theoretical value of the reflection peak is different from the actual value,which is caused by the surface defect of the film.CdS@SiO2 film was further coated to compare the saturation changes.EDS,SEM and other film analysis showed that SiO2 was successfully coated on the surface of CdS microspheres with the reflection peak increasing and the saturation increasing. |
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