Co-assembly Of Block Copolymers And Inorganic Nanoparticles Within Emulsion Droplets

The self-assembly of block copolymer has obtained various nanostructures such as spherical,lamellae,vesicles,and rods.Inorganic nanoparticles have special properties and functions.The co-assembly of block copolymers and inorganic nanoparticles generate novel organic/inorganic hybrid nanostructures under confined conditions.The hybrid material can combine the advantages of both the polymer and the inorganic nanoparticle to give the assembly structure more functionality,and has broad application prospects in the fields of Raman enhancement,photothermal therapy,antibacterial and drug release.However,the distribution of inorganic nanoparticles in the polymer matrix can significantly affect the properties and applications of the hybrid structure.Therefore,people have begun to pay attention to the scientific problem of controllable and adjustable distribution,alignment and orientation in the assembly.This thesis will focus on the study of the co-assembly of PS-SH modified gold nanoparticles with different size and volume fraction and block copolymer PS-P4 VP.In order to induce the morphology transformation of the block copolymer during the co-assembly process,the experiments adjust the conditions of the gold nanoparticles under three-dimensional limited conditions by emulsion evaporation.It is found that the morphology of micelle structures closely related to the size and volume fraction of inorganic nanoparticles.We mainly study and get the following relevant conclusions:(1)Polystyrene-b-poly(4-vinylpyridine)was confined in a three-dimensional emulsion droplet by emulsion evaporation method,and the interface property was adjusted by selecting an appropriate surfactant,which was prepared due to interface instability.A vesicle structure with uniform morphology was prepared.(2)The vesicle usually obtained by solution method.But it only can be encapsulated a small amount of inorganic nanoparticles,and excessive inorganic nanoparticles can precipitate.The vesicles obtained by the emulsion evaporation method greatly enhance the load capacity,and the utilization rate of the vesicles is significantly enhanced.(3)The block copolymer and inorganic nanoparticles in the emulsion droplets under 3D confinement.We change the size and volume fraction of the inorganic nanoparticles in the system,and induced the transformation of the micelle morphology.It can be observed from the experimental results that the gold nanoparticles change,a series of interesting changes have taken place in the morphology of the co-assembly structure.(4)In the process of co-assembly of inorganic nanoparticles and block copolymers,the entropy effect and the enthalpy effect determine the arrangement of nanoparticles.Among them,the induced enthalpy effect mainly depends on the compatibility of the surface ligand of the modified inorganic nanoparticles with the polymer matrix.The entropy effect mainly depends on the translational entropy of inorganic nanoparticles and the conformational entropy of polymer matrix chains.Small-sized nanoparticles cause little loss of conformational entropy and can be evenly distributed in the polymer matrix,while large-sized nanoparticles have stronger entropy repulsion.