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Structural color is a color formed by the interaction between light and micro nano structure. It has the characteristics of high brightness and high saturation. If the microstructure forming the structural color is not destroyed, the structural color will never fade. It is of great significance to reduce the pollution caused by traditional printing and dyeing to develop the structure colored fibers and fabrics through the color development method of structure color.

Recently, the research team of East China Normal University used a spraying process to accurately assemble colloidal photonic crystals (PC) in each yarn of polyester (PET) fabric. The prepared pc/pet fabric has saturated and durable color, good softness and high air permeability.

The researchers developed a two-step spraying process. PET fabric can be regarded as hierarchical porous structure, with large cracks between yarns and small gaps between fibers. When the SiO2 colloidal solution was sprayed for the first time, a thin liquid film was rapidly formed on the surface of PET fabric, and then the limited volume of colloidal solution was completely absorbed into the porous yarn by capillary force. With the evaporation of the solvent during the heating process, the particles spontaneously precipitate to form a liquid colloid PC, which is then transformed into a solid PC between the fibers. In the subsequent PA adhesive spraying, due to the same capillary interaction, PA nanoparticles were also enriched on the surface of pet yarn filled with SiO2 particles. When the sample is heated above the glass transition temperature and then cooled to room temperature, the PA nanoparticles melt, solidify, and wrap the PC structure and pet yarn to finally form a colorful pc/pet fabric.

It is verified that the spraying process can produce pc/pet fabrics with uniform, saturated and diverse structural colors. When the incident angle and reflection angle of light change from 0 ° to 30 °, 45 ° and 60 °, the reflection wavelength of Red PC modified fabric correspondingly changes from 650 nm to 605 nm, 555nm and 503nm.

The durability test results show that the color of the fabric remains unchanged when it is washed by water or washing machine. When the PC modified fabric is subjected to more violent operations, such as brushing and ultrasonic treatment, its structure remains intact. With the help of mask, PC patterns of trees, flowers and deer can be easily made on the fabric.