Synthesis And Assembly Of Nanoparticles Modified By Polydopamine

The monodisperse particles can be assembled through a specific pattern to produce structural color materials that are colored by optical principles.The ordered crystal structure and semi ordered quasicrystal structure have attracted wide attention in the research and application of particle assembly.The construction of traditional crystalline and amorphous structure mainly consists of silica,polystyrene and polymethyl methacrylate particles.These nanoparticles can efficiently be assembled crystalline and amorphous materials through a mature assembly method.The crystalline and amorphous structure material is the main way to construct structural color materials,which has been widely applied in pigment coating,color display,biological detection and optical anti-counterfeiting.Polydopamine is a natural melanin.In addition to its strong absorbability of light,it also exhibits strong adhesion similar to the adhesion proteins in mussels.Therefore,the application of polydopamine in particle assembly of structural color materials can not only effectively improve the brightness of structural color,but also have some properties of polydopamine,which widens the applications of structural color materials in many ways.In this paper,the aim of this study is to synthesize polydopamine modified nanoparticles,fabricate structural colored materials and its application.The specific work is as follows:?1?A simple and efficient method was developed for preparing polymethylmethacrylate?PMMA?polymer nanoparticles doped with polydopamine and silica?PDA@SiO₂?composite nanoparticles coated with polydopamine.By adjusting the concentration of dopamine,methyl methacrylate and methacrylic acid,we obtained PMMA nanoparticles with uniform morphology,50-300 nm diameter and controllable polydopamine doping amount.By adjusting the concentration of dopamine and the particle size of SiO₂ core particles,the PDA@SiO₂ composite nanoparticles with controllable particle size and PDA shell thickness can be obtained.?2?The effect of polydopamine on the color of structural color materials was studied.Polydopamine addition solved the structural color white phenomenon.By dispersing polydopamine doped PMMA particles into the basic materials of contact lens?hydroxyethyl methacrylate HEMA?,we obtained the clloidal crystal structural hydrogel,which optimized the color saturation because of the adorption of PDA.The colored hydrogel is bright,which has great potential application in the field of colored contact lenses.In addition,the PDA@SiO₂ amorphous structural color obtained by spraying fast-drying technology also achieved high color apparent degree.By controlling the particle size,coating amount of dopamine and concentration of the spraying particles,the three properties of the color can be controlled.?3?The effect of polydopamine on the mechanical strength of structural color materials was studied.In this section,the adhesion of polydopamine improved the mechanical strength of the amorphous structural color material.Based on the self-polymerization of polydopamine,the structural color material is further enhanced by ammonia vapor treatment.Shear-off test,sandpaper friction,finger wiping and ultrasound destruction proved that the mechanical strength of PDA@SiO₂ structural color materials treated with ammonia was 4 times than the structural color materials without ammonia treatment on the strength of adhesive tape.It is proved that the adhesion properties of the PDA@SiO₂ structurlly colored materials are universally suitable by the tests on different substrates.?4?PDA@SiO₂ colloidal crystal microspheres were prepared by the droplet limited domain assembly technique based on colloidal particles.The melanin and adhesion properties of polydopamine made PDA@SiO₂ colloidal crystal microspheres have higher saturation color and mechanical strength than the SiO₂ microspheres.The function of the surface functionalization of polydopamine further realized the function of PDA@SiO₂colloid microspheres as biomolecular microcarriers.The labeling of fluorescent biomolecules and the detection of human IgG antigen showed that the colloidal crystal microspheres can be used in biological multivariate analysis.