Preparation And Application Of Silver Nanoparticles Doped Amorphous Photonic Crystals

The generation of the rich and colorful structural colors in photonic crystals(PC)originates from the special physical structure of the material itself with special visual effects caused by scatter,diffraction,and interference of light.The structural colors come from the physical structure of PC,without the use of chemical colorants such as pigments or dyes,effectively reducing environmental pollution.In addition,the structural color of PC has the characteristics of brightness,vividness,and ability of never fading,making it an ideal material for constructing smart responsive devices and textile coloring,which has received wide attention from domestic and foreign scientists.Colloidal photonic crystals(CPC)as a kind of color-adjustable material have been widely used in the sensing field by converting external stimuli into recognizable color changes.The traditional CPC sensor with an ordered structure is influenced by the angle-dependent structural color,which may cause errors in the sensing process.In this research,we constructed an angle-independent amorphous photonic structure(APS)and introduced black silver nanoparticles(Ag-NPs)which possessed strong visible light absorption effects into the APS system to prepare APS film and further further studied the related construction methods,mechanisms and adjusting ways of structural colors.The prepared APS films possessed angle-independent,noniridescent and highly saturated structural color.The high saturation is attributed to the incoherent scattered light uniformly absorbed by the added Ag-NPs throughout the visible spectrum.In addition,angle-independent color temperature sensor based on APS film was successfully prepared.Compared with the traditional temperature sensor based on photonic crystal,this noniridescent color temperature sensor was more accurate and practical,accounting for the avoiding color confusion caused by the angle-dependence of structural color.Furthermore,we attached monodisperse polymer nanoparticles to the surface of textile yarn to obtain APS textiles with high saturation,angle-independent structural colors,and antibacterial properties,providing favorable theoretical support and practical experience for the construction of biomimetic APS on textiles and the development of functional antibacterial textiles and expanding the application of APS in aseptic packaging and decoration fields.In this thesis,the research work mainly includes the following four aspects:(1)constructing polystyrene-butyl acrylate-methacrylic acid[P(St-BA-MAA)]nanospheres by emulsion polymerization.Investigating the particle size distribution,monodispersity,and surface charge of the nanospheres and exploring the influence of monomer content and surfactants on particle size and monodispersity.(2)Constructing angle-independent amorphous photonic crystal films with high saturation on glass slides and polyethylene terephthalate(PET)films by spray coating and spin coating,respectively,and studying their optical properties.(3)Developing an Ag-NPs doped hydrogel temperature sensor based on APS films,and testing its temperature sensing effect and optical properties,revealing the response mechanism of the temperature sensor.(4)Constructing angle-independent structural coloration and antibacterial APS textiles on polyester-cotton surface using spray coating and studying their antibacterial effects,optical properties,and flexibility.The research results are as follows:(1)In the emulsion polymerization method,P(St-BA-MAA)nanospheres with a monodisperse distribution of230.3-292.7 nm were prepared by adjusting the amounts of styrene monomer and surfactants.The particle size distribution of the nanospheres was narrow(PDI<0.05),and the Zeta potential was less than-30 mV.(2)Ag-NPs and P(St-BA-MAA)particles were assembled on the surface of glass slides by spray coating.The rapid evaporation of the solvent and the addition of particles of different sizes inhibited the formation of long-range ordered structures of colloidal particles and self-assembled into short-range ordered structures.Ag-NPs and two sizes of P(St-BA-MAA)particles were assembled on the flexible PET film by spin coating,and the high solid content of the emulsion and the rapid assembly process at 65℃ effectively inhibited the self-assembly of colloidal particles from forming long-range ordered structures.At the same time,the doping of Ag-NPs significantly increased the saturation of APS film’s structural colors.(3)APS temperature sensors were constructed by introducing N-isopropyl acrylamide(NIPAm)hydrogels into the APS film,and a visual and angle-independent sensitive temperature response from 24 to 40℃ was achieved.(4)High saturation and angle-independent APS films were successfully constructed on polyester-cotton surface by spray coating.Due to the doping of Ag-NPs,the structural color textiles showed excellent antibacterial effect against Staphylococcus aureus and Escherichia coli.The results of this thesis possesses great significance for the regulation of APS structural colors and extension of its application in sensing and textile coloring.