Preparation Of Photonic Crystal Composite Film And Its Application In Textiles

Textile coloration is mainly achieved by the means of using chemical coloring agents such as(dyes and pigments).The structural color of photonic crystal(PCs)is formed by its specific nanostructure which can confine and control the propagation of electromagnetic waves in specific wavelength ranges,and thus realizing the brilliant structural coloration of textiles.The self-assemble methods by using colloidal nanospheres as building blocks to fabricate structurally colored textile is an effective way for the ecological coloring of textiles.However,the structural stability of the assembled PCs on textile substrate is usually poor due to the weak connection forces,such as hydrogen bonds and van der Waals forces,existed among the nanospheres,which results it vulnerable to the strong external forces,such as bending,rubbing and folding,hampering their practice application in textile field.In addition,the porous,rough and uneven surface of textile substrates is not conducive to the orderly assembly of nanoparticles,and the complex self-assembly process,the long assembly time,which restricts itself to rapidly and extensively assemble,and is not conducive to industrial production.In order to solve the problems of structural stability and assembly efficiency of PCs,this study fabricates the sandwich-like PCs structural color film to improve its structural stability,which can be applied to textile substrates with different organizational structures.Specifically,this study mainly involves the following three aspects of research work:(1)Study on the preparation and performance of PCs structural color film,which includes the effects of the composition of assembly solution(solid content of nanosphere emulsion,anti-cracking agent,melanin,and so forth.)on the film-forming and optical properties of structural color film,the effects of assembly conditions(temperature and time)on the structural stability and color saturation of structural coloration films,and the effects of photonic crystal mass per unit area on the optical properties and structural stability of structural color films.(2)Study on the effect of carrier layer on the structural stability and optical properties of composite PCs film.In particular,the effect of type and concentration of water repellent finishing agent on the degree of water repellent modification(water repellent grade)of fabric and the effect on the preparation of subsequent carrier layer were studied,and then the effect of carrier layer thickness(mass per unit area)on the binding fastness of composite membrane was discussed.(3)The influence of encapsulation layer on the stability and optical properties of photonic crystal structure.Based on the preparation of two-layer films(bearing layer and photonic crystal layer)on the fabric,the preparation and properties of the third layer(encapsulation layer)were studied,including the influence of encapsulation polymer types and encapsulation coating process conditions on the optical properties and structural stability of photonic crystal composite films.The structural stability of sandwich-like photonic crystal composite films was discussed,which includes the fastness properties of acid and alkali resistance,water immersion resistance,soap resistance,bending resistance,and the optical properties of sandwich PCs composite films.The results show that:(1)The optimized assembly precursors are composed of self-synthesized nanosphere emulsion with 30 wt%of solid content,6 wt%of anti-cracking agent(on the weight of nano-microsphere emulsion)and 0.8 wt%of carbon black(on the weight of nano-microsphere emulsion).The optimized self-assembly conditions are the 60°C/5 min or70°C/4 min.The PC composite films prepared under the optimized conditions show the bright and uniform structural colors and excellent structural stability.The thickness of the PCs layer(expressed indirectly by the mass of the photonic crystal per unit area)also affects the saturation and structural stability of the PCs composite film.When the mass of the PCs per unit area is 12 g/m~2,the fabricated PCs composite film shows bright structural color and excellent structural stability.(2)The PCs with ordered structure was fabricated on the textile via constructing the flat surface on loose,porous and rough fabric substrates.Firstly,the fabric substrate is treated by water repellent finishing agent.Secondly,the surface of fabric substrate is coated with a carrying polymer.When the water repellency level of the fabric was grade 3 and the mass per unit area of the bearing polymer layer was 40–60 g/m~2,the photonic crystal layer constructed on the bearing layer was bright in color,stable in structure,and with excellent soaping and bending stability.(3)The encapsulation layer can further improve the structural stability of PCs composite film.When the concentration of encapsulating agent A is 10 wt%,the PCs composite film not only has the bright structural color,but also has the excellent structural stability.The structural color of sandwich-like PCs on textile substrate has the excellent acid and alkali resistance,water immersion resistance,soap resistance,bending stability,and iridescence effect.