| Photonic crystals,also known as photonic band-gap materials,selectively block or confine the propagation of light at a specific frequency through periodic arrangement of at least two kinds of dielectric materials.Due to their unique optical properties,Photonic crystal functional systems are widely used in the field of molecular recognition.On the one hand,we have constructed photonic crystals with different functions,including solid SiO2 and hollow spherical SiO2;on the other hand,we have realized the visual recognition detection of 4-nitrophenol by constructing polymer photonic crystals with inverse opal,and developed a high-performance diethylamine fluorescence sensor based on hollow spherical SiO2 photonic crystals.The specific research contents and results of this thesis are as follows:(1)The monodisperse SiO2 microspheres with particle size ranging from 180 nm to 350 nm were prepared by the improved Stober method.Through the vertical deposition method,the SiO2 microspheres were assembled on the surface of the slide,and the single-layer and double-layer SiO2 microspheres photonic crystal films were obtained.Then different functional monomers were filled in the gap of the single-layer films,and the inverse opal photonic crystal films were obtained after light curing acid etching.SEM analysis shows that the SiO2 microspheres are regular spherical and uniform in size,and they are highly orderly stacked in the film.The reflection spectrum and optical photos show that the color of the film changes with the change of viewing angle in the range of 0°?60°.(2)Based on the excellent optical properties of inverse opal polymer photonic crystal films,a new 4-nitrophenol sensor was prepared by using hydroxyethyl methacrylate as the functional monomer.Because of its unique self-expression optical properties,optical signals can be easily observed by naked eye through color change.By precisely adjusting the molar ratio between functional monomer and crosslinker,the results show that the sensor with the ratio of 5:1 has the best sensitivity;By presenting different film colors,the real-time,fast and semi quantitative detection of(10?80)mM 4-nitrophenol solution is realized.In addition,the sensor shows good selectivity,interference immunity and reusability.(3)The PS microspheres with positive charge on the surface and good dispersion in the size range of(180?300)nm were prepared by dispersion polymerization.Then PS@SiO2 microspheres were obtained by sol-gel method.The PS@SiO2 microspheres were self assembled on the glass surface by vertical deposition method,and different color photonic crystal films were obtained.After high temperature calcination,hollow sphere SiO2 photonic crystal films were obtained.The color change of structure color film before and after calcination was studied.SEM and TEM analysis showed that the size of PS and PS@SiO2 microspheres was uniform;the shell thickness of PS@SiO2 was uniform,and the shell thickness increased slowly with the increase of TEOS;the PS@SiO2 microspheres in the film were packed tightly with face centered cubic,and the band gap position was red shifted obviously with the increase of the diameter of the microspheres;TEM of hollow spherical SiO2 showed that PS microspheres were removed successfully;After filling the gap of hollow spherical silicon dioxide film with common solvents,such as water,ethanol,acetone,toluene,the color saturation of the film increases,the reflection intensity increases,and the color changes when contacting with the liquid.(4)Based on hollow sphere SiO2 photonic crystal,a fluorescent sensor for high performance detection of diethylamine was developed.The difference of band gap position in enhanced fluorescence emission is studied.The results show that the blue band edge near the fluorescence emission wavelength has the best enhancement effect,which is about 256%.The selective detection of diethylamine in the concentration range of 5×10-7 M to 5×10-1 is realized. |
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