| Summary: | 碩士 === 國立臺灣科技大學 === 化學工程系 === 100 === Developing powerful and reliable strategies: to covalently functionalize graphene, for efficient graphene grafting, and achieving precise interface control, are challenging due to the strong interlayer cohesive energy and the surface inertia of graphene. Here we present versatile and efficient grafting strategies to functionalize graphene nanosheets. An alkyne-bearing graphene core was used to prepare polymer-functionalized graphene using ‘grafting to’ and ‘grafting from’ strategies in combination with reversible chain transfer and click chemistry. The use of the ‘grafting to’ approach allows full control over, limited length grafted polymer chains, while permitting a high grafting density to a single graphene face, resulting in good solubility and processability. The ‘grafting from’ approach offers complementary advantages, such as the grafting of high molecular weight polymer chains and a better coverage ratio on the graphene surface; however, the extra steps introduced, the presence of initiating groups and the difficult in controlling the grafted polymer lead to decreased processability. The use of the ‘grafting to’ approach offers several advantages compared to the ‘grafting from’ approach, e.g. it gives rise to well defined and controlled grafted polymer chains, good processability and high grafting density (note: grafting density decreases with an increase in the chain length of the grafted polymer). However, the ‘grafting from’ approach allows high molecular weight polymer chains to be appended to surface of graphene, thereby maintaining an adequate grafting density. The polymer-functionalized graphene formed by the ‘grafting from’ approach yields longer grafted polymer chains, thereby effectively improving the polymer’s solubilizing strength.Various types of polymer chains have been successful covalently tethered to graphene nanosheets using these two approaches, producing various molecular brushes with multifunctional arms resulting in water-soluble, oil-soluble, acidic, basic, polar, apolar, and variously functionalized polymers. This work describes versatile methodologies for the preparation of individually dispersed graphene nanosheets with the properties already described.
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