Study On The Light Manipulation Performance Of Polystyrene Microspheres

Polymer microspheres are spherical particles of nanometer or micron scale,which have been widely used in the field of optical materials due to their advantages of good monodispersity,strong permeability and low preparation cost.Among them,amorphous photonic crystals and light diffusing agents as polymer microsphere based optical materials.They can change the direction and intensity of light by using the optical properties of microsphere itself and the sub wavelength structure formed,and realize the manipulation of light,which has important application value.However,the preparation conditions of amorphous photonic crystals are harsh,and the structural color saturation is poor.For light diffusing agents,solid polymer microspheres have low light transmittance,while hollow microspheres have poor regularity.To solve the above problems,in this thesis,two monodisperse submicron polymer microspheres with different structures and functions were prepared by different polymerization methods with styrene as the main monomer.Based on the different characteristics of the two microspheres,new functional coatings were prepared by spraying method,and the optical properties of the material were explored.The research work of the thesis is carried out at two following aspects:Firstly,the poly（styrene-methyl methacrylate-acrylic acid）（P（St-MMA-AA））microspheres with core-shell structure were synthesized by emulsion polymerization.The size of the microspheres was controlled by adjusting the amount of emulsifier.Titanium carbide（Ti C）black nanoparticles with strong light absorption ability were used as a new type of light absorber and mixed with polymer microsphere dispersion.The non-iridescent structural color coatings were prepared rapidly and in large area by spraying method.The experimental results show that the operation process of preparing amorphous photonic crystals by spraying method is simple and time-saving.The color saturation of non-iridescent structural colors can be significantly improved by introducing Ti C into the amorphous photonic structure.The color gamut of structural colors can be broadened by adjusting the doping amount of Ti C,the particle size of microspheres and the mixing ratio of double-sized microspheres.In addition,the material has stronger adhesion than inorganic structural colors,and can show bright color rendering effects on substrates of different materials and shapes.It is expected to be used in the fields of powder pigments,writing and printing.Secondly,polystyrene（PS）hollow polymer microspheres were prepared by the hard template method.Using silica（Si O₂）as the template,polystyrene@silica（PS@Si O₂）core-shell microspheres were prepared by the dispersion polymerization method.Hollow PS microspheres were obtained after etching.Based on the uneven polymerization in the preparation of hollow microspheres,the traditional PS microsphere preparation process was improved.The effects of Si O₂ template,polymerization temperature and monomer dosage in the dispersion polymerization system on the core-shell structure of composite microspheres were discussed separately.It is found that the activation of the template can significantly improve the effect of silylation modification,and then improve the regularity of the microspheres.Polymerization temperature and monomer dosage can affect the morphology and monodispersity of microspheres.By adjusting the process parameters,composite microspheres with regular microscopic morphology and good monodispersity were finally obtained.Hollow PS microspheres with different particle sizes and wall thicknesses were prepared by controlling the size of the template particles and the mass ratio of monomer/template.Utilizing the the deformability of this material,it is innovatively applied to the specific detection of organic vapors.Due to the good light transmittance of the hollow microspheres and the high refractive index difference between the interfaces,the material can be used as a novel light diffusing agent to prepare functional coatings,and has application value in the field of light diffusing materials.