Construction And Application Of Hollow/Janus Colloidal Materials Based On Melamine Resin Microspheres

Melamine-formaldehyde microspheres(MF)are polymer colloid microspheres formed by polycondensation of melamine and formaldehyde.Compared with traditional colloidal microspheres such as PS and PMMA,the MF microspheres have cheaper raw materials,higher density,higher refractive index,and numerous-NH2,-NH,-OH functional groups on the surface to reduce Au+,Ag+,Pt+ plasma in situ.This thesis builds a series of hollow and Janus colloidal materials with different structures and functions based on MF microspheres.First,melamine and paraformaldehyde were condensed and polymerized under the catalysis of acid to obtain melamine-formaldehyde microspheres with uniform particle size and single dispersion.Ag nanoparticles were reduced in situ by the reducing property of the melamine-formaldehyde microspheres to obtain a MF/Ag composite colloidal microspheres,and Ag2S-Ag composite hollow colloidal microspheres were prepared using MF/Ag microspheres as templates.Secondly,hierarchical nickel hydroxidenitrate hollow microspheres with electrochemical properties were prepared in one step by solvothermal method with melamine-formaldehyde microspheres as sacrificial template,ethanol and water as solutions,and hierarchical nickel hydroxidenitrate hollow microspheres was used in supercapacitors.Thirdiy,based on MF microspheres,MF/Au,MF/Ag,MF/ZnO and MF/PANI Janus particles were prepared by interface protection method.Taking MF/Au Janus particles as an example,the application of Janus particles as the particle emulsifier in emulsion stabilization and catalyst in interfacial catalysis was explored.The main contents are as follows:(1)Melamine-formaldehyde microsphere were prepared by the condensation polymerization of melamine and paraformaldehyde under acid-catalyzed conditions.And the MF/Ag composite colloidal microspheres are obtained by reacting rich functional groups on the surface of melamine-formaldehyde microspheres with silver ammonia([Ag(NH3)2]+)that were reducted in-situ to form a dense Ag nanoshell.Subsequently,Ag2S-Ag composite hollow colloidal microspheres were prepared by solvothermal method,using MF/Ag composite colloidal microspheres as a template and ethanol as a solution and thioacetamide(TAA)as a sulfur source.By adjusting the dosage of TAA,the reaction timeand other reaction parameters,the formation mechanism of Ag2S-Ag composite hollow colloidal microsphereswith different structures was discussed.(2)Basic nickel nitrate microspheres were synthesized by template sacrifice method,using MF microspheresas sacrificial templates,water and ethanolas solution,and nickel nitrate hexahydrate as the solute.By adjusting the reaction parameters such as the ratio of water to ethanol in the medium,the dosage of solute nickel nitrate hexahydrate,the reaction time and other reaction parameters,the mechanism of the template sacrifice method to form basic nickel nitrate hollow microspheres was explored.And the basic nickel nitrate hollow microspheres with the optimized structure and composition were used as the positive electrode material of supercapacitors to explore its application in electrochemical energy storage.(3)A series of Janus colloid particles with different structures and functions were constructed based on MF microspheres through interface protection.Firstly,as a colloidal template,MF microspheres are assembled at the gas-liquid interface to form twodimensional colloidal crystals.Then,the exposed part of the MF microspheres in the air was coated with PDMS.Using an interface protection method,MF/PDMS array was obtain.The MF/PDMS array was put into silver ammonia solution,tetrachloroauric acid solution,zinc acetate and sodium hydroxide ethanol solution,and aniline and ammonium persulfate solution respectively to obtain MF/Au,MF/Ag,MF/ZnO and MF/PANI Janus particles.In addition,MF/Au Janus particles were used as particle emulsifiers and interface catalysts to conduct emulsion emulsification stabilization experiments and pnitroanisole interface catalytic reduction experiments to explore their potential applications.