Preparation Of Structural Elements For Rapid Construction Of Heat-resistant Photonic Crystals And Their Applications In Textile Substrates

Photonic crystals follow Bragg diffraction law optically.By changing the structural parameters of photonic crystals,such as crystal plane spacing and effective refractive index,the chromatic structure of photonic crystals can be effectively adjusted to produce bright and facile chromatic effect.It is an effective way for textile ecological coloration to construct structurally colored photonic crystals on the surface of textile substrate by self-assembly of colloidal nano-spheres as structural elements.However,the process of colloidal self-assembly is a complicated and time-consuming process,so that the preparation efficiency of photonic crystals is low and it is difficult to prepare them in large scale.The preparation efficiency of colloidal photonic crystals can be significantly improved by reconstructing liquid photonic crystals.However,the preparation of liquid photonic crystals by concentration of colloid or by supersaturated precipitation also has the problem of complicated process.On the other hand,the basic elements of commonly used organic nanometer microspheres have the problems of high temperature resistance and low interforce after assembly,so the thermal stability and mechanical stability of the constructed photonic crystal structure are usually poor,which greatly limits the practical application of photonic crystal structure coloring technology in the field of textile ecological coloring.In view of the above problems,this thesis mainly focuses on the following two aspects :(1)Design and synthesis of high solid polystyrene(PS)colloidal nano microspheres emulsion,combined with the external force induced assembly to achieve rapid large-scale preparation of structural chromic photonic crystals.The effects of dispersants on colloidal emulsion and self-assembled photonic crystal structures in the polymerization process were studied.The assembly speed and color effect of photonic crystal with different solid content were analyzed.(2)High crosslinking PS nanospheres were designed and prepared,and the correlation of crosslinking degree with glass transition temperature and refractive index was studied.The chromogenic photonic crystal structures with high thermal stability and mechanical stability were prepared by self-assembly of the chromogenic photonic crystal.The main research results are as follows:1.Monodisperse PS colloidal emulsion with particle size of 170 ? 350 nm was synthesized by emulsion polymerization.The agglomeration phenomenon in the polymerization process of high solid content emulsion was solved by piecewise feeding and the introduction of dispersant,and the high solid content PS nano-sphere emulsion with good monodispersion was prepared.The colloid emulsion with better monodispersity and higher emulsion yield can be obtained by adding 1.5 ? 2 wt% dispersant at 1 h of reaction time.The self-assembly process of photonic crystal structure was completed in 1 min by shear-induced self-assembly of the nanosphere emulsion with high solid content.With the increase of the solid content of the colloid emulsion,the saturation of the shear-induced self-assembly photonic crystal becomes higher.2.The heat stability and refractive index of PS nanospheres can be significantly improved by increasing the cross-linking degree of PS nanospheres.With the increase of the amount of crosslinking agent,the crosslinking degree and glass transition temperature of the microspheres increased significantly,and the sphericity of the microspheres was maintained at high temperature,and the photonic crystal structure was maintained at high temperature too.By high temperature treatment of the structured color photonic crystal assembled by nanometer microspheres with high crosslinking degree,the double bond reaction rate in the microspheres can be further improved to increase the refractive index of the crystal,and the stable infiltration of the structured color photonic crystal can be obtained.With soft polymer membranes as base material,nanometer microspheres crosslinked type to assemble primitives that building the photonic crystal structure of the soft qualitative migrated to a gap in the photonic crystal structure of polymer,at the same time high crosslinking between nanometer microspheres and soft polymer still has high refractive index difference,so as to realize the high structure stability of structure to the attraction photonic crystals with high color saturation.