Preparation And Application Of Crosslinked Polymer Composite Micro/nanoparticle

The cross-linked polymer has a three-dimensional network chemical structure,which can’t be dissolved in any solvent,nor be melted with heat.When the polymer was cross-linked,the mechanical properties,solvent resistance,and thermal stability of the material will all be changed to a great extent.Compared to macroscopical materials,when the size of a material is reduced to nanometer scale,its properties would be greatly different.For example,the degree of cross-linking shows great effect on the permeability of the material to molecules,ions,and microorganisms,which could be used to design the membrane materials with selective permeability.Although cross-linked micro-nano polymer materials have many excellent properties,few studies are focus on them.Therefore,this paper focuses on the development of the novel methods for the preparation of cross-linked polymer microspheres and/or cross-linked polymer nanoshell materials,and then applies the as-prepared nanomaterials in molecular imprinting,cancer therapy,and plasmonic tuning,as well as smart photo-controlled movement.The main research contents and results are as follows:1.Highly cross-linked polyethylene glycol dimethacrylate(PEGDMA)microspheres were prepared by solvothermal precipitation polymerization.The results indicate that this method can produce highly cross-linked PEGDMA microspheres with monodisperse,in which the monomer concentration can attain to 20 vol%,which is much higher than the traditional precipitation polymerization system(5 vol%).Further,the polymerization rate also increases significantly that the yield reached 95%within 4 hr.By controlling the reaction conditions,including solvent composition,monomer concentration,reaction temperature,polymerization time,the ratio of crosslinker to functional monomer,and the type of comonomer,we proposed the reaction mechanism of solvothermal precipitation polymerization.In addition,the prepared microspheres were used as molecularly imprinted materials,which can selectively recognize the bisphenol A in the aqueous solution.2.The surface of porous SiO2 microspheres was coated with a layer of cross-linked polydopamine(PDA),as a lysozyme-imprinted layer,through the oxidative coupling polymerization.First,we prepared magnetic mesoporous SiO2 microspheres,which contains a large number of mesoporous channels.Then,a layer of polydopamine was coated on the surface of SiO2,named as Fe3O4@fibrous SiO2@PDA.The TEM images and nitrogen sorption-desorption data show that there are still a large number of pores on the surface of SiO2 after surface coating,which greatly facilitates the diffusion of the protein molecules.Further studies shown that the microspheres can selectively recognize and adsorb the lysozymes from the egg white,and the combined lysozymes can also be rapidly released upon the irradiation of the NIR laser.More importantly,the released lysozymes still exhibit high biological activity.3.We have prepared a new type of multifunctional,near-infrared photothermal therapy,magnetic resonance imaging,and magnetic resonance imaging.Firstly,we prepared Fe/Fe3O4@SiO2@PDA as magnetic molecular imprinted materials.When the nanomaterials are introduced into cells,these nanoparticles can specifically capture intracellular CAT and inhibit the biological actnanoparticle for the integration of cancer therapy platforms by combining radical therapyivity of CAT,thereby inducing an increase in the hydrogen peroxide content in cancer cells.The intracellular Fenton reaction is then used to decompose the accumulated hydrogen peroxide into ·OH radicals,which further increase the oxidative stress in cancer cells and induce apoptosisof cancer cells.In addition,nanoparticles have a good near-infrared photothermal effect,so that photothermal therapy can be realized.At the same time,the magnetic separation,targeting,and magnetic resonance imaging(MRI)can also be achieved since the magnetic cores.Therefore,this work provides an efficient method for the integration of cancer diagnosis and therapy.4.Anisotropic metal nanostructures were successfully prepared inside the crosslinked resorcinol-formaldehyde(RF)polymer capsules by a confined seeded growth method.The morphology,dimension and optical properties of the nanostructures were all manipulated by the crosslinked RF capsules.In the first case,anisotropic Ag/Au nanoplates were used as seeds and embedded within RF nanoshells to anisotropic grow silver nanoplates.TEM images show that this method can efficiently synthesize silver nanoplates with uniform size.In the second case,we used the template method to prepare rod-shaped RF capsules.The anisotropic Cu nanorods were successfully prepared by the seeded growth method.Based on the strong absorption cross section,the synthesized Cu nanostructures were used as photothermal elements to drive the smart devices.