Precise Design And Controllable Preparation Of Nanocrystals Based On Star-shaped Block Copolymer Templates

Nanomaterials have become a focused research in numerous of fields due to their unique physical and chemical properties.The fabrication of nanomaterials with controllable size and morphology has always been the key effect on the development of nanotechnology.Currently,fabrication of nanomaterials by using block copolymers as templates became one of the most effective methods to achieve highly controlled nanomaterials,especially using star-shaped block copolymers which have more stable spatial structures and better uniformity compare with linear polymers.Although the fabrication of nanocrystals using block copolymers as templates has been reported in many works,the quantitative control of the nanocrystal size by the template has not been deeply discussed.In this thesis,a series of nanocrystals were prepared by using multi-arm star-shaped block copolymer poly?acrylic acid?-b-poly?styrene??PAA-b-PS?as nanoreactors,and the high consistency of PAA micelles size and nanocrystals size was also proved.The simulation of PAA micelles size is realized by introducing the scaling theory for star-shaped polymers.Combined with living radical polymerization kinetics,the quantitative model was constructed to achieve the precise design of nanocrystals size,and extend the application of living radical polymerization kinetics from the field of polymers to the synthesis of inorganic nanocrystals.This work provide the theoretical basis for the precise fabrication of nanocrystals with more complex structures,and also the guidance for the large-scale industrial production of nanocrystals.The specific research content are as follows:?1?Fabrication of amphiphilic multi-arm star-shaped block copolymer PAA-b-PSA series of the multi-arm star-shaped block copolymers Pt BA-b-PS with?-cyclodextrin as the center were synthesized by ATRP.After the hydrolysis of tert-butyl groups on the Pt BA block by adding trifluoroacetic acid,a series of the amphiphilic multi-arm star-shaped block copolymers PAA-b-PS were synthesized.The copolymers were characterized via proton nuclear magnetic resonance?¹H-NMR?,fourier transform infrared spectroscopy?FT-IR?and gel permeation chromatography?GPC?.The experimental results showed that the molecular weight of each Pt BA arm can be controlled by adjusting the polymerization time of the t BA monomer,and finally the molecular weight of each PAA arm can be controlled.?2?Nanocrystals capped with PS polymers prepared by using amphiphilic multi-arm star-shaped block copolymers PAA-b-PS as nanoreactorsA series of monodisperse spherical Fe₃O₄ nanocrystals were prepared by using the monomolecular micelles of amphiphilic star-shaped block copolymer PAA-b-PS as nanoreactors.The experimental results showed that all of the Fe₃O₄ nanocrystals are uniform in size,and the size increase with the increase of molecular weights of each PAA arm.Further,the Ag and Cu₂O nanocrystals with same size were prepared with same templates,indicating that the templates have high accuracy and universality in preparing different kinds of nanocrystals.?3?The theoretical simulation of amphiphilic multi-arm star-shaped block copolymers PAA-b-PS monomolecular micelles in fabrication of nanocrystalsSeven multi-arm star-shaped polymers Pt BA were hydrolyzed with trifluoroacetic acid to obtain the corresponding star-shaped PAA monomolecular micelles.The size of resulted nanocrystals were highly consistent with the size of PAA monomolecular micelles.By introducing the scaling theory,the size of PAA micelles was simulated and the quantitative size control of the nanocrystalline was realized.Combined with living radical polymerization kinetics,the precise design of nanocrystals size can be achieved by controlling the conversion rate of t BA monomer during the polymerization,and the application of living radical polymerization kinetics was extended to the field of inorganic nanocrystals synthesis.