Two-Dimensional Porous Polymers: From Sandwich-like Structure to Layered Skeleton
Jinhui Zhu†‡, Chongqing Yang‡, Chenbao Lu‡, Fan Zhang*‡, Zhanhui Yuan*†, and Xiaodong Zhuang*‡
† College of Materials Engineering, Fujian Agriculture and Forestry University, 350002 Fuzhou, P. R. China
‡ State Key Laboratory of Metal Matrix Composites, Shanghai Key Laboratory of Electrical Insulation and Thermal Ageing, School of Chemistry and Chemical Engineering, Shanghai Jiao Tong University, 200240 Shanghai, P. R. China
Inorganic porous materials have long dominated the field of porous materials due to their stable structure and wide applications. In the past decade, porous polymers have generated considerable interest among researchers because of their easily tunable porosity, carbon-rich backbones, and prominent physical properties. These attributes enable porous polymers to be used in various applications such as sensing, gas separation and storage, catalysis, and energy storage. However, poor dispersibility has long hindered the development of porous polymers. A majority of the reported porous polymers can only be synthesized with amorphous structure through direct precipitation from solutions during reactions. The rational design and synthesis of porous polymers with controllable morphology, such as two-dimensional (2D) morphology, remains great challenge.
Two-dimensional nanomaterials have attracted considerable interest because of their unique properties, which originate from the intrinsic chemical structures and 2D dimensionality. Among 2D nanomaterials, 2D porous polymers, which possess the advanced features of polymers, porous materials, and 2D nanomaterials, have been a rising star. Conventionally, polymerization strategies for generating 2D porous polymers mainly include the cross-linking of multiarmed monomers in 2D-space-confined environments, such as crystalline solid surfaces, liquid–liquid interfaces, and liquid–air interfaces. However, these methods always involve complicate operations, e.g., under vacuum, sophisticated equipment, film transfer technology, exfoliation, and so on and, most importantly, are difficult to scale up.
To overcome this synthesis obstacle, 2D nanomaterials, such as graphene, can be used as 2D templates for synthesis of sandwich-like 2D porous polymers and porous carbon nanosheets. p-Bromobenzene-, p-cyanobenzene-, polyacrylonitrile-, and amino-functionalized graphene are used as templates for direct surface polymerization through reactions such as Sonogashira–Hagihara coupling reaction, condensation reaction, ionothermal reaction, reversible addition–fragmentation chain transfer polymerization, Friedel–Crafts reaction, and oxidation reaction. Therefore, sandwich-like 2D conjugated microporous polymers, Schiff-base type porous polymers, covalent triazine frameworks, hyper-cross-linked porous polymers, and mesoporous conducting polymers can be easily prepared. Beyond graphene, other excellent 2D nanomaterials, e.g., MoS2, can also act 2D templates to construct 2D porous polymers and corresponding hybrid materials. In addition, 2D morphology for porous polymer can be achieved without 2D templates in a few cases. For instance, olefin-linkage-linked covalent organic frameworks can be synthesized through Knoevenagel condensation reaction. As is known, porous polymers can serve as carbon-rich precursors to generate heteroatom doped porous carbons for energy storage and catalysis. Thus, one benefit of 2D porous polymers is new access toward porous carbon nanosheets through direct pyrolysis without using inorganic porous templates. In this Account, we summarize recent research on 2D porous polymers and corresponding porous carbon nanosheets.
Link:
https://pubs.acs.org/doi/10.1021/acs.accounts.8b00444
Down this paper：
Two-Dimensional Porous Polymers From Sandwich-like Structure to Layered Skeleton.pdf
