Study On The Self-assembly Of Block Copolymer And Its Co-assembly With Nanoparticles

Amphiphilic block copolymers in a selective solution can self-assemble into avariety of nanometer-sized micellar aggregates. The self-assembled morphologies arecontrolled by numerous control parameters, such as copolymer chemical composition,pH value, temperature, block length, the common solvent, the selective solvent,interfacial tension between the solvent and insoluble block(s) and addictives. Themorphology of the formed aggregates can be sphere, vesicle, tube, cylinder, and ring,depending on the aforementioned parameters.The traditional preparation method to prepare block copolymer method canseparate into direct method and indirect method. Now some new preparation methodcome into our eyes, for example, the solvent evaporation method, blending method(premix and postmix) and template method. The fundamental principle of thesemethods is similar but the generated micellar structure have great differences. In ourresearch, we studied the different preparation method. First, we study the influence ofblock copolymer blending method on the final structure in dilute solution and obtainthe mesh-like nanostructure through gradual blending method.Preparing micellar morphology using block copolymer has received extensiveattention and research. In this study, we developed a novel blending strategy, namely,the gradual blending method, to tune the micellar structure. Different from the mostcommonly used premixing blending method, which different block copolymers arepremixed in a common solvent before their individual self-assembly, the gradualblending method involves gradually adding one type of block copolymer into the pre-generated micellar solution formed from another type of block copolymer.Moreover, we obtained a novel mesh-like vesicle from the self-assembly of themixtures of P4VP43-b-PS26-b-P4VP43and P4VP43-b-PS366-b-P4VP43in1,4-dioxane/water solution using the gradual blending method. Moreover, theformation pathway of the mesh-like vesicles was investigated by kinetically trappingthe intermediate morphologies of the micelles. Our fi ndings suggest that the gradualblending method can be an alternative strategy to replace widely used blendingmethod, that is, the pre-mixing blending method, to control the micellar structures andmorphologies. We also studied the self-assemble under confinement condition,obtaining nanotube micelles with layered structure. Then introducing PS modifiednanoparticles in the solution, we hope that the Au nanoparticles can put in order in thenanotubes.Block copolymer can self-assemble into various morphologies underconfinement. In our study, we use PS-b-P4VP to obtain the nanotube micelles in thealumina template, and the structure vary with the ratio of the two block. We introducethe PS modified gold nanoparticles, hoping that PS can drive the gold nanoparticles inthe nanotubes in regular arrangement thus preparing composite material of inorganicnanoparticles and copolymer, this part of the work has made preliminary progress.From the above research, we know that the block copolymers can be assembledto generate the morphology structure and assembly method of rich, has a direct effecton morphology. We could obtain more abundant micelle morphology for differentsystem, and it has vital significance to expand the application field for the micelle.