Controllable Preparation Of Ring/Hollow Nanomaterials Using Monomolecular Micelles As Template

Nowadays,the shape and composition of nanoparticles were diverse,and they were usually manufactured using methods such as photolithography and thin film deposition techniques,wet chemical synthesis,or a clever combination of the two.The properties of nanoparticles were determined by their material composition and nano-geometry.Nano-geometry defined electrons,excitons,photons,surface plasmons,magnetic spin,etc.,and realized new functions and applications.The shape and size of the nanoparticle determined its physical,chemical,and biological properties,such as cell uptake,transportation,and biological distribution in different organs.Therefore,the new nanotopology had important potential applications in various scientific fields.Among the various shapes of nanoparticles,"ring"nanoparticles were particularly interesting as artificial complex nanostructures with ring cavities.Nanorings,as a kind of hollow nanostructures,had caused a wide range of attention.Due to the unique nanoring structure with ring-shaped cavity,they had a wide range of applications in optics,electronics,magnetism and catalysis.The traditional preparation methods of nanorings such as colloid method,macromolecular template method,electron beam lithography,molecular beam epitaxy and other methods were expensive.The process was cumbersome and complicated,and the operation was extremely inconvenient.The size control of the nanorings was completely depended on complicated experimental technology and equipment could not achieve precise control of the size of nanorings in a true sense.Therefore,this paper proposed a new method for preparing nanorings,which used multi-arm star-like amphiphilic block polymer PS-b-PAA as templates to prepare a series of nanorings of different sizes.By systematically adjusting the molecular weight of the PS block and the PAA block in the amphiphilic block polymer PS-b-PAA,precise control of the inner diameter and wall thickness of the nanoring was realized,providing a theoretical basis for the precise and controllable preparation of nanorings.The specific research content was as follows:(1)Preparation of multi-arm star-like amphiphilic block polymer PS-b-PAAThrough sequential atom transfer radical polymerization(ATRP)technology,multi-arm star-like block polymers with different molecular weights,polystyrene-b-poly-tert-butyl acrylate(PS-b-Pt BA)were prepared,under acidic conditions,the protective group tert-butyl group was removed by hydrolysis to obtain the multi-arm star-like amphiphilic block polymer PS-b-PAA.The prepared star polymer was characterized by ¹H-NMR,FT-IR,TEM and GPC,which confirmed the successful synthesis of multi-arm star-like amphiphilic block polymers.By controlling the polymerization reaction time,precise control of the molecular weight of the polymer could be achieved.(2)Preparation of TiO₂ nanorings with multi-arm star-like amphiphilic block polymer PS-b-PAA as templatesUsing the multi-arm star-like amphiphilic block polymer PS-b-PAA as templates,a series of TiO₂ nanorings with different sizes were prepared.The characterization results showed that the size of the TiO₂ nanorings was highly consistent with the size of the template.By systematically adjusting the molecular weight of the PS block and the PAA block in the amphiphilic block polymer PS-b-PAA,precise control of the inner diameter and wall thickness of the nanoring was achieved.At the same time,TiO₂nanorings had a good ability to catalyze and degrade organic dyes.(3)Preparation of hollow nanoparticles with multi-arm star-like amphiphilic block polymer PS-b-PAA as templatesHollow Au,Ag,Cu₂O and Fe₃O₄ nanoparticles were prepared by using multi-arm star-like amphiphilic block polymer PS-b-PAA as templates.The size of the prepared hollow nanomaterials was uniform,which was consistent with the size of the template.It was proved that the multi-arm star-like amphiphilic block copolymer PS-b-PAA has the accuracy and universality in the preparation of hollow nanomaterials.