Construction Of Assemblies Based On Single-micelle Hollow Polymer Spheres

With the advantages of structural flexibility,diverse composition and low density,single-micelle structures have broad application prospects in the fields of adsorption,catalysis,energy storage and drug delivery.In addition,single-micelle structures with small size and structural uniformity can also be used as basic building blocks to participate in the assembly of multiple complex structures.In this thesis,polybenzoxazine-based single-micelle hollow polymer spheres(SHPS)with uniform structure and adjustable size were synthesized by emulsion polymerization based on a single-micelle-driven synthesis strategy.The effects of micelle droplet size,polymerization monomer concentration and reaction temperature on the morphology of SHPS were also investigated.However,such prepared micelle-sized hollow polymer spheres are difficult to be separated from the colloidal solution due to their small size and low density.To solve this problem,we have made use of two-dimensional carbon-based materials-graphene oxide(GO)and inorganic layered materials magnesium-aluminum layered double hydroxide(Mg Al-LDH),the separation and collection of hollow polymer spheres are achieved by surface charge-driven electrostatic agglomeration strategy using the charged property of colloids,while constructing to obtain novel composite materials.The details are as follows.Polybenzoxazine-based hollow polymer spheres with a diameter of 20-30 nm were prepared by emulsion polymerization using F127/dodecanol composite micelles as the core and resorcinol,formaldehyde and n-propylamine as polymerization precursors.The shell thickness of the SHPS can also be adjusted within 6-8.6 nm by controlling the ratio of precursors to micelle droplet.By varying the polymerization reaction temperature,not only dispersive hollow polymer spheres can be obtained,but also the assembly consisting of 4-28 SHPSs can be prepared.In order to solve the problem of micelle-scale hollow polymer spheres being difficult to separate from solution,the positively charged hollow polymer spheres were captured from solution by electrostatic interaction with the help of a negatively charged two-dimensional carbon-based material,GO.As a result,two-dimensional sandwich-like nanosheets with GO as the middle layer and the hollow polymer spheres as the coating layer were prepared.Interestingly,the hollow polymer spheres were observed to be arranged in an ordered hexagonal honeycomb array on the graphene oxide surface.The arrangement rules of hollow polymer spheres on the GO surface was investigated by adjusting parameters such as p H and the mass ratio of SHPS/GO.We also illustrate the formation mechanism of this arrangement by model calculation.By introducing the two-dimensional inorganic layered material with a positive surface charge,Mg Al-LDH,the negatively charged hollow polymer spheres were enriched to the surface of Mg Al-LDH through electrostatic interaction.Significant phase separation occurs in the colloidal system.The resulting metal oxides were removed through subsequent steps such as high temperature pyrolysis,acid pickling and water washing,then the three-dimensional network structure composed of hollow carbon spheres was prepared.