Study On Highly Stable Photonic Crystals With Structural Colors On Textile Based On Light Curing Technology

Biomimetic structural coloration of photonic crystals is a new way to achieve textile dyeing,and the resultant structural color is bright,vivid,lifelike and agileand changeable.However,the present photonic crystals with structural colors constructed on the textile are currently poor in stability.When the photonic crystals with structural colors are subjected to folding,bending,rinsing and rubbing,the photonic crystals are prone to cracking and falling off from the textile,which can directly make the structural color effect worse even disappears.In this paper,two methods based on UV-curing technology are designed and developped to improve the stability of photonic crystals with structural colors on textiles.This study will provide a theoretical basis and practical basis for the preparation of highlt stable photonic crystals with structural colors on textiles,and further promote the practical application of biomimetic structural coloration of textiles.The research work of this thesis mainly includes the following two aspects:(1)Designing and preparing a photo-curable working solution composed of functional monomer and initiator,then the working solution isapplied in the textile substrates with the photonic crystals with structural colors by dipping method.After the UV-curing treatment,the stability of photonic crystals could be significantly improved.The suitable working liquid system for photo-curing is determined by investigating the influence of type and concentration of functional monomer and initiator on the optical properties and mechanical properties of the cured film.Moreover,the stability of treated photonic crystals with structural colors was tested by folding,friction and ultrasonic washing tests,and the optical properties of photonic crystals with structural colors were systematically analyzed and discussed.(2)Designing and preparing a photo-curable colloidal microsphere ink consisted of colloidal microspheres,functional monomers,initiators and "coffee ring" inhibitors,then the prepared inks was printed on the textile substrates via digital jet printing technology,and then the substrates was cured by UV-light to achieve a patterned photonic crystals with highly high stability and vivid colors.By analyzing thestructural color effect and arrangement of resultant photonic crystals,the amount of each component in the ink system is systematically optimized.By regulating the pH,viscosity and surface tension,the properties of the prepared photocurable microsphere ink are adjusted.Futhermore,the stabilityof the photonic crystals with structural colors is tested by ultrasonic washing and rubbing test,and the optical properties of patterned photonic crystals with structural colors are systematically analyzed and discussed.The results show that:(1)By investigating the effects of functional monomers and initiator on the optical properties and mechanical properties of the cured films,it is concluded that the photo-curable working solution should be composed of functional monomers hydroxyethyl acrylate(HEA)and 1.0 %(percentage of monomer)initiator diphenyl(2,4,6-trimethylbenzoyl)phosphine oxide(TPO),the cured PHEA film has high transparency,good mechanical propertiesand strong adhesion with textile substrates.(2)After the photo-curing working liquid finishing,the stability od resultant photonic crystals with structural colors could be significantly improved.The microspheres of photonic crystals are arranged neatly and densely,Particularly,the resultant photonic crystals are still not appear to fall off from the textile substrate,and the microspheres are still arranged regularly and compactly after the folding,friction and ultrasonic washing tests.Moreover,after the photo-curing finishing,the photonic crystals constructed by colloidal microspheres with a large difference in refractive index of PHEA film still presents uniform and bright structural colors with obv ious iridescent effect.As the particle size of the microsphere increases or the viewing angle increases,a significant red shift occurs.(3)By exploring the concentration of soft shell-hard core P(St-HEA)microspheres,monomer HEA,photoinitiator 2-hydroxy-2-methylpropiophenone(1173)and “coffee ring” inhibitor 2-2-diethoxyacetophenone(DEG),a suitable photocurable colloidal microsphere ink system can be constructed.The properties of the resultant photocurable colloidal microsphere ink can be controlled by regulating the pH,surface tension and viscosity of the inks.(4)After the prepared inks is printed on the textile substrates by digital jet printing technology,a 250 W UV-lamp with a center wavelength of 365 nm is used to carry out a curing treatment,the photonic crystals with regular structure,bright color and obvious iridescence can be constructed about 3.0 min,and the coloring mechanism of resultant photonic crystals conforms to the Bragg diffraction law.The resultant photonic crystals with structural colors still not significantly fall off from the textile substrates after the ultrasonic washing and rubbing tests,which indicates that the prepared photonic crystals chromogenic structure has good stability.