Rapid Preparation And Properties Of Highly Stable Photonic Crystals With Structural Colors On Textile Substrates

At present,promoting the transformation and upgrading of traditional industries to high-end,intelligent and green,enhancing the leading ability of green development and realizing high-quality development of the textile industry are undergoing green reform.Photonic crystal structure coloring is a new environment-friendly coloring method for textile substrates,which can be realized without applying chemical coloring agents such as dyes or pigments.In this paper,the effects of weaving parameters and surface hydrophobic properties on the color generation of photonic crystal structure on textile substrates were investigated.Then,the photonic crystal structure was rapidly constructed on the selected textile substrate by spraying method to obtain the bright structural color with iridescence phenomena.Furthermore,the "net"formed by the adhesive was used to wrap the photonic crystals through secondary spraying adhesive to improve its structural stability.This study may provide theoretical basis and practical experience for the rapid preparation of highly stable photonic crystal structure on textile substrates.The main research contents of this paper included the following three aspects:(1)Effects of weaving parameters and surface hydrophobicity of textile substrates on the structural color of photonic crystals.Using black polyester yarn as raw material,different specifications of textile substrates were woven by controlling the yarn size,warp and weft density and fabric weave,and then using poly(styrene-methacrylic acid)(P(St-MAA))colloidal microspheres as structural units,the photonic crystal structure was self-assembled on the water-repellent textile substrates.The effects of different weaving parameters and surface hydrophobic properties of the substrates on the photonic crystals and its structural color effects were analyzed to select the suitable textile substrates.(2)Rapid preparation and characterization of photonic crystal structure coloring textiles by spraying method.The P(St-MAA)microspheres suspension was pretreated by centrifugation to obtain the pre-assembly solution.The pre-assembly solution was applied to the substrates by spraying to quickly prepare the photonic crystal color structure with iridescence phenomena.The influences of the processing parameters such as the mass concentration of the pre-assembly solution,spraying distance and spraying time on the photonic crystal structure and its structure color were investigated.The mechanism of structural color changes in the process of self-assembly were explored and the optical properties of photonic crystals were analyzed.(3)Preparation and properties of highly stable photonic crystals on textile substrates.The P(St-MAA)/WPU composite photonic crystals were prepared by spraying waterborne polyurethane resin(WPU)adhesive on textile substrates bearing P(St-MAA)photonic crystal structure.The preparation parameters of the composite photonic crystals were optimized,and the optical properties and stability of the composite photonic crystals were analyzed.The results showed that:(1)Bright photonic crystal structure colors could be obtained when the concentration of microsphere assembly solution was only 2 wt%on the plain weave substrates,and the tighter the plain substrates and the finer the yarn,the more orderly the photonic crystal structure,the more favorable the bright structural color.When the twill and satin fabrics were used as the substrates,the concentration of microsphere assembly solution would be higher than 2 wt%to get the bright color.The more hydrophobic the polyester substrate was,the more obvious cracks would appear in the constructed photonic crystals,and the color brightness would decrease gradually.By adjusting the particle size and observation angle of P(St-MAA)microspheres,the hue of structural color could be controlled.(2)When the concentration of pre-assembly solution was 30.0 wt%,spraying distance was 20 cm,spraying duration was 4?6 s,and drying temperature was 80?,a bright structural color could be obtained on the black polyester substrates with plain weave and high tightness within 60 s by spraying.The process of structural color formation conformed to the Bragg diffraction law,that was,when the observation angle remained unchanged,the crystal plane spacing decreased and the effective refractive index decreased,and the structural color shifted to blue.(3)When the WPU concentration was lower than 8 wt%,the color of the composite photonic crystals did not change significantly,while when the WPU concentration was higher than 8 wt%,the color of the composite photonic crystals showed a tendency to reddish.Compared with P(St-MAA)photonic crystals,the water resistance and wear resistance of P(St-MAA)/WPU composite photonic crystals were obviously improved.The structural color of P(St-MAA)/WPU composite photonic crystals could be controlled by changing the particle size of P(St-MAA)colloidal microspheres and observation angle.