Polymer brushes can be used to tailor the physical and chemical properties of materials on demand to meet potential applications. Therefore, fabrication of polymer brushes with well-defined structure and functional groups enables the engineering of new materials with diverse functions. In addition, two-dimensional (2D) materials have their unique physical/chemical properties and potential applications in (opt)electronics, catalysis, energy storage, sensing, and other related fields. However, the dispersibility, chemical stability, charge transport behavior, mechanical properties of the 2D materials hinder their further applications. Therefore, combining polymer brushes and 2D materials may bring in new properties which are not available by either of them alone. This thesis focuses on brushing up 2D materials (from inorganic to organic) with universal photografting techniques.
(1) The first chapter introduces the outline and research content of the thesis.
(2) The second chapter describes the background of 2D materials and polymer brushes. In particular, this chapter analyzes mechanisms, drawbacks and benefits of different polymerization methods, and also summarizes the general approaches to grow polymer brushes on 2D material surfaces, coupling with potential applications of polymer functionalized 2D materials.
(3) The third chapter shows the motivation and aim of this thesis.
(4) The fourth chapter discusses the results of the functionalization of hexagonal boron nitride (hBN), MoS2, graphitic-carbon nitride (gCN), alkyl-polydopamine (alkyl-PDA), and conjugated 2D polymers (2DPs) with polymer brushes by the same self-initiated photografting and photopolymerization (SIPGP) method and their related applications in detail, respectively. First, the direct photopolymerization of vinyl monomers results in the formation of thick and homogeneous polymer brushes covalently bounded to hBN. The brush layer mechanically and chemically stabilizes the material and allows facile handling as well as long-term use in water splitting hydrogen evolution reactions. Second, the chapter demonstrates the MoS2 can be directly modified with polymer brushes by SIPGP. After modifying MoS2 with polymer brushes, the dispersibility of polymer brushes-modified MoS2 was obviously improved. Third, the polymer brushes functionalized gCN significantly improves the dispersibility. Application of polymer brush functionalized gCN as excellent recyclable substrates for an outstanding SERS as well as photocatalytic degradation of dyes is demonstrated. Fourth, to directly obtain the 2D materials with functional groups, the chapter proposes a facile method to prepare amphiphilic polymeric Janus nanosheets with hydrophilic PDA and hydrophobic alkyl chains at both sides. Benefiting from the Janus property of the alkyl-PDA nanosheets, the nanosheets can be grafted polymer brushes through photografting and be conjugated Fe3O4 nanoparticles selectively onto the PDA side. Finally, the chapter shows that various polymer brushes can be directly grafted onto 2DPs and freestanding system is also obtained. Moreover, it is found that the morphology of freestanding system quickly and reversibly responds to solvent quality by shrinking/stretching. (5) The fifth chapter addresses the general conclusion and future prospective of the whole work.
(6) The sixth chapter describes the experiment part of the whole thesis.
| Identifer | oai:union.ndltd.org:DRESDEN/oai:qucosa:de:qucosa:38293 |
| Date | 07 February 2020 |
| Creators | Sheng, Wenbo |
| Contributors | Fen, Xinliang, Voit, Brigitte, Synytska, Alla, Technische Universität Dresden |
| Source Sets | Hochschulschriftenserver (HSSS) der SLUB Dresden |
| Language | English |
| Detected Language | English |
| Type | info:eu-repo/semantics/publishedVersion, doc-type:doctoralThesis, info:eu-repo/semantics/doctoralThesis, doc-type:Text |
| Rights | info:eu-repo/semantics/openAccess |
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