Preparation Of Polystyrene Microspheres And Properties Of Photonic Crystal Prepared From Them

Hollow microspheres have the advantages of large surface area,low density and high load capacity,and are used in many fields such as micro-/nano-reservoirs and reactors,energy,drug loading,biomedical and sensors.The refractive index of the polymer in the hollow microsphere shell and the air in the cavity differ greatly.The uniform outer surface of the hollow microspheres and the inner surface of the spherical or irregular structure cause strong scattering and multi-directional reflection of the incident light.These reasons make the hollow structure microspheres have a strong shielding effect on light.In this paper,we prepared a hollow PS-PDVB microsphere with uniform morphology by an improved one-step swelling method,and studied its internal structure.We used hollow PS-PDVB microspheres as raw materials to prepare colloidal crystals and amorphous colloidal crystal structures by vertical deposition and multiple spin coating techniques.By adding silica powder as a regulator,we obtained a near-infrared reflectance spectrum similar to that of plant leaves,with a spectral similarity of 0.9998.The addition of the reflective protein Ref A1 to the amorphous colloidal crystal structure imparts a stimulating response characteristic to the coating.The specific research contents are as follows:?1?We prepared monodisperse polystyrene microspheres with a particle size of about 1?m by dispersion polymerization,and then used them as seed microspheres to prepare PS-PDVB hollow microspheres by one-step swelling method.The seed microspheres,the swelling agent,the emulsifier and the initiator are mixed to form a stable emulsion,after the PS seed microspheres are sufficiently swollen,the crosslinking reaction of the DVB shell layer is initiated.?2?We prepared monodisperse polymer microspheres of different particle sizes using soap-free emulsion polymerization and dispersion polymerization.The emulsion containing the colloidal microspheres was prepared by dispersing monodisperse colloidal microspheres having the same particle diameter into water at room temperature,and the concentration of the colloidal microspheres in the emulsion was about 0.03 wt%.The solid substrate previously subjected to hydrophilic treatment was vertically inserted into the prepared emulsion,and vertically deposited at 80°C and60%humidity to obtain colloidal crystals.?3?We used the opal structure as a template to fill the voids with a precursor sol of SiO₂.The material was placed in a tube furnace and calcined in air to obtain SiO₂having an inverse opal structure.The heating rate was 4°C min^-1,the calcination temperature was 600°C,and the time was 2 h.?4?We used PS-PDVB hollow microspheres to prepare bionic camouflage coatings.The coating structure is mainly prepared by a vertical deposition method,a gravity deposition method,and a multiple spin coating method.The coating prepared by the hollow microspheres has a large number of PS-air interface structures,which can better simulate the reflection mechanism of light in plant leaves,thereby simulating the reflection spectrum.The silicon powder with a particle size of about 200 nm is added to the surface of the coating,and the reflection spectrum of the coating is adjusted by the strong absorption capacity of the silicon powder for ultraviolet light,so that it is similar to the spectrum of the plant leaves.The surface of the coating is coated with Ref A1protein,giving it the ability to stimulate response changes.