Study On Synthesis And Properties Of Polymer Janus Particles

The structure,properties and morphology of polymer Janus particles with environmental sensitivity,due to the presence of amphiphilic or differential structural components in the polymer chains,will present complex changes in response to external changes with the external environment changes.These changes can be skillfully used to prepare functional materials,such as drug delivery,smart coatings,solid surfactants,catalytic reactions,microreactor,micromotor,etc..Among them,The morphology of multiphase liquid mixture stabled by Janus particles changes with changes of the external environment such as temperature,p H,and ionic strength,so that it can also be used as an environment-sensitive material.Until now,the synthesis of Janus particles with stimuli-sensitive polymers is gradually changing from controllable morphology to performance control.Therefore,the synthesis and functionalization of stimuli-sensitive polymer Janus particles will still have enormous research potential.The paper adopted soap-free emulsion polymerization,dispersion polymerization and phase separation,with common monomers methacrylic acid and its esters,styrene,etc.as raw material,a series of environment-sensitive micro/nano polymers particles were successfully synthesized by accurately controlling the polymerization process and regulating the proportion of monomers.Meanwhile,the influence of the proportion of hydrophilic and hydrophobic monomers and the polymerization method on the micromorphology and environmental sensitivity of polymer particles was systematically investigated,the Ag@polymer composite particles were been successfully synthesized by two simple and efficient methods,achieving the goal of further functionalization of the polymer.The main research content is as follows:In chapter 1,the evolution of the morphology,the types of environmental susceptibility,the preparation methods,and the application fields of polymer Janus particles were reviewed.In chapter 2,a one-pot two-step soap-free emulsion polymerization process was chosen to synthesize a series of nanoscale particles with good monodispersity,glycidyl methacrylate(GMA)and methyl methacrylate(MMA)were selected for copolymerization to synthesize polymer seed particles,and followed by the addition of methacrylic acid(MAA)and styrene(St)for further polymerization,a series of nanoscale particles with good monodispersity can be synthesized by regulating the ratio of monomers.Then,the polymer morphology,structure,monodispersity,particle size,and emulsification were tested through Fourier Transform Infrared(FT-IR),Scanning Electron Microscopy(SEM),Transmission Electron Microscopy(TEM),Electron Spectroscopy(EDS),Dynamic Light Scattering(DLS),Optical Microscopy(OM),etc..Meanwhile,we successfully designed two methods for loading Ag particles: using 1,6-hexanediamine to functionalize the polymer that cannot be directly coordinated with Ag+,and then to load Ag+.Ag@polymer composite particles can be obtained by reducing Ag+ with ascorbic acid;Selecting polymer particles that can be directly combined with Ag+,Ag+ can be adsorb on the surface of the polymer by positive and negative charge based on the carboxylate on the surface of the polymer particles,Ag@polymer composite particles can be also obtained by reducing Ag+ with hexamethylenetetramine.The method is simple and suitable for most of the polymer microparticles for Ag nanoparticle loading.In chapter 3,One-pot two-step,one-pot multi-step dispersion polymerization and swelling polymerization was chosen to synthesize a series of nanoscale particles with different morphology and chemical properties,GMA was selected for polymerization to synthesize polymer seed particles,and followed by the addition of MAA and St,MMA and St,or St for further polymerization,a series of nanoscale particles with good monodispersity can be synthesized by regulating the ratio of monomers.The polymer morphology,structure,monodispersity,particle size,and emulsification were tested through FT-IR,SEM,TEM,EDS,DLS,OM,etc..The obtained Janus particles exhibit p H responsiveness.Additionally,the Ag@polymer composite particles were also successfully synthesized.In chapter 4,One-pot two-step phase separation was chosen to synthesize a kind of micron-sized polymer particle with good monodispersity,MAA,MMA,Butyl methacrylate(BA)was selected for polymerization to synthesize linear polymer chains,and followed by the addition of BA and St for further polymerization,a kind of micron-sized bowl-like polymer Janus particle with good monodispersity can be synthesized by regulating the ratio of monomers and solvent.The polymer morphology,structure,monodispersity,particle size,and emulsification were tested through FT-IR,SEM,TEM,EDS,DLS,OM,etc..The obtained Janus particles exhibited p H responsiveness.The Ag@polymer composite particles were also successfully synthesized.In summary,when a series of obtained Janus particles with a stimuli-sensitive polymer are used as solid surfactants,they have stronger adhesion at the liquid-liquid interface than isotropic polymer particles and thus have a strong stability to multiphase liquid mixtures.The combination of polymer Janus particles with inorganic materials is also an option for the functionalization of polymer particles,which is conducive to the synthesis of new materials with excellent performance and environment-friendly.Meawhile,the studies have shown that the parameters of micronanoscale polymer particle including morphology,particle size and monodispersity can be effectively controlled by controlling the monomer ratio and using appropriate polymerization methods.In addition,two simple and efficient methods have been designed to successfully synthesize Ag@polymer composite particles,reaching the purpose of further functionalization of the polymer,and achieving the goal of using a simple green method to efficiently regulate the morphology and function of polymer particles.