Synthesis And Micellar Behavior Of Amphiphilic Block Copolymer Atrp Method

Molecule self-assembly has been more and more widely used in the building model of biological engineering technology,molecule-apparatus,surface engineering and nanotechnology, and it is exhibiting a splendid future in its application.Due to its specific physical and chemical properties,molecules are able to be self-assembled to form different shapes and structures of compound from several nanometers to several microns in scale.Meanwhile,when being influenced by a weak external field,the morphology of molecules self-assembly has a comparatively strong response,which enables us to have better control on its self-assembling behavior.Amphiphilic diblock copolymer,like small molecular surfantants,lipid amphiphilic molecular in selective solutions can self-assembled to all kinds of aggregates.The morphologies include microspheres, nanotube,wormlike,cylindrical,vesicles,and lamellar,its size from nano- to micron- level even greater.Several kinds of nanomaterials and Photonic crystals can be fabricated based on the self-assemble properties of block copolymer.Therefore the assembly structure of block copolymer has the wide application prospect and the huge value in nanotechnology,biology,medicine and so on.Based on such a background,we synthesized two kinds of amphiphilic diblock copolymer, controlling the corresponding morphologies are achieved.Specific studies are summarized below.1.Using PMEG-Br as the macroinitiator,CuBr/2,2'-bipyridine(Bpy) as the catalyst and ligand,well-defined amphiphilic block copolymer PMEG-b-PMMA was synthesized via atom transfer radical polymerization(ATRP).The structure of diblock copolymer was characterized by Fourier transform infrared spectroscopy(FT-IR) and Nuclear magnetic resonance spectroscopy (¹HNMR).Molecular weight and molecular weight distribution of the diblock copolymer were determined by Gel permeation chromatography(GPC).2.The aggregation behavior of PMEG-b-PMMA in THF/water solvent mixture at different water content in the binary solvent has been characterized using Transmission electron microscopy (TEM).The reversed micellization behavior of PMEG₄₅-b-PMMA₃₃ in toluene has been investigated. By increasing the concentration of copolymer,we found these aggregates to undergo morphological transformations from spheres to cylinders and eventually to reticulation structures and explainded the possible mechanism of the morphological evolution.3.Using amphiphilic block copolymer PMEG-b-PMMA as templates,PEI as a reducing agent of Ag⁺,silver nanoparticles were synthesized by sonicating.The product was characterized by TEM,X-ray Diffraction(XRD) and UV-Vis spectroscopy.The TEM results revealed that the size of the resulting silver nanoparticles prepared basing on the copolymer was strongly dependent on the initial concentration of the silver ion solution and the copolymer.4.A reactive copolymer of poly(methyl methaerylate)-block-poly[3-(trimethoxysilyl) propyl methacrylate](PMMA-b-PTMSPMA) was synthesized by atom transfer radical polymerization (ATRP) method.The product was characterized by Fourier transform infrared spectroscopy (FT-IR),Nuclear magnetic resonance spectroscopy(¹HNMR) and Gel permeation chromatography (GPC).Due to the reactive trimethoxysilyl groups of the PTMSPMA domain was hydrolyzed easily into trihydroxysilyl groups,which were sequently transferred into cross-linked polysilsesquioxane by the condensation reaction,self-assembly was performed by dissolving PMMA-b-PTMSPMA in a THF/methanol mixture,followed by a sol-gel process catalyzed by triethylamine.Thus, organic/inorganic hybrid nanomaterials were prepared by this simple procedure.