Confined Self-Assembly Of Polymers And Polymer-Grafted Nanoparticles

Polymers exhibit different self-assembly behaviors under confinement from that under unconfinement,which provides an effective way to prepare new and quality assemblies.It is a hotspot and frontier of polymer science and soft matter science.In this dissertation,we studied the self-assembly behavior of the polymers and polymer/inorganic nanoparticles under confinement and the preparation and structure control of the organic/inorganic hybrid materials.The effects of polymer blending,the shape and size of nanoparticles,the molecular weight of polymer ligands on the structures and the arrangement of the hierarchical assemblies were investigated.Details of the research contents and the results are summarized as follows:1.Hierarchical self-assembly of a PS-b-P4VP/PS-b-PNIPAM mixture into multicompartment micelles and their response to two-dimensional confinement:In this section,we investigated the co-assembly behavior of the PS9.8k-b-P4VP10k/PS16k-b-PNIPAM9.5k blends in dilute solution and the effect of two-dimensional(2D)confined environment on the hierarchical cooperative self-assembly.It was found that the mixture of the PS9.8k-b-P4VP10k/PS16k-b-PNIPAM9.5k could cooperatively self-assemble into pupa-like multicompartment micelles(MCMs)in dilute solution under unconfinement.The MCMs were formed by hierarchical self-assembly of small spherical micelles(SSMs),which were co-assembled from the PS9.8k-b-P4VP10k/PS16k-b-PNIPAM9.5k mixture.However,when the block copolymer mixture solution was introduced into the nanopores of an anodic aluminum oxide(AAO)template,long multicompartment micelles(LMCMs)with a period multilayer structure were obtained under the 2D confinement.In addition,the diameters of the LMCMs as well as the thickness of the periodic layers are found to be rationally tuned by changing the diameter of the AAO nanopores.2.The preparation of hierarchical ordered superstructures of spherical nanoparticles through the emulsion interface self-assembly:We investigated the self-assembly behavior of PS-grafted gold nanospheres(AuNPs@PS)confined at the emulsion interface,which was constructed by the internal hexadecane(HD)liquid phase and the external aqueous phase.The results indicated that the AuNPs@PS building blocks self-assembled into 3D ordered colloidosomes with hexagonal arrangement of AuNPs and the interparticle distance of the adjacent AuNPs could be tuned by changing the length of the PS ligands.Moreover,the 2D sheet-like superlattices could be obtained by increasing the volume ratio of the internal HD phase.By using the same strategy,the platinum nanoparticles(PtNPs)could self-assemble into hierarchical colloidosomes and superlattices,which proved that this method was universal.In addition,AuNPs grafted with biocompatible ligands could self-assemble into biodegradable colloidosomes through the emulsion interface self-assembly.The biodegradable colloidosomes had high photothermal conversion effect and surface enhanced Raman scattering.3.The preparation of hierarchical colloidosomes with a highly ordered and oriented arrangement of gold nanorods(AuNRs)and their internal orientation regulation:The PS-tethered anisotropic AuNRs were confined at the emulsion interface to prepare hierarchical colloidosomes with a highly ordered and oriented arrangement of AuNRs.The results indicated that the arrangement and orientation of AuNRs was influenced by the the curvature of the colloidosomes and the interactions between the adjacent AuNRs.The ordered arrangement and orientation of the AuNRs could be realized by increasing the diameter of the colloidosomes or decreasing the length of the polymer ligands.4.The preparation of hierarchical ordered superstructures of anisotropic gold nanocubes(AuNCs)and AuNCs/spherical nanoparticles:3D colloidosomes with highly ordered arrangement of anisotropic AuNCs were prepared through the confined assembly at the emulsion interface.The arrangement of AuNCs on the surface of the colloidosomes was related to the diameter of the colloidosomes.When the size of the colloidosomes was small,the strong frustration effect made the rigid AuNCs to be arranged in pentagonal and hexagonal arrangement.When the diameter of the colloidosomes increased,the frustration effect was weakened and then AuNCs were aligned face-to-face.Moreover,2D superlattices with highly ordered face-to-face configuration could be obtained by increasing the volume ratio of the internal HD phase.In addition,the binary superlattices could be obtained by the self-assembly of the blending of AuNCs and spherical NPs.The arrangement of AuNCs and spherical NPs on the surface of the binary superlattice was influenced by the entropy repulsion of AuNCs and spherical NPs.The entropic interaction of the two building blocks could be regulated by adjusting the size of the spherical NPs and the length of the polymer ligands,thus generating the binary superlattices with controllable distribution of the spherical NPs.