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An important driver of material design is to improve the performance of the material, while enabling inanimate organic or inorganic materials to achieve certain functions similar to those of organisms. Although functional materials having excellent properties, such as carbon-based materials represented by carbon nanotubes (CNTs) and graphene, have been shown to have a wide range of uses, it is necessary to introduce other "intelligent" groups in order to fully realize their application potential. The formation of hybrid materials system.
As a kind of stimuli-responsive polymer, a polymer brush can form a hybrid material system in situ on the surface of a carbon-based material, and thus has the advantage of introducing a macromolecule stimuli-responsiveness to a functional material. The functionalization of the polymer on the surface of the carbon-based material effectively improves its dispersibility and compatibility, and also imparts intelligence to the carbon-based material. However, the homogeneous grafted polymer layer reduces the excellent performance of the carbon-based material itself. The synergy effect of the performance of the two weakened.
In response to this problem, the Intelligent Polymer Group of the Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences carried out a series of scientific research on the polymer brush unidirectional grafting of carbon-based film materials in an attempt to obtain a two-dimensional Janus film, which is expected to achieve “Janusâ€. The functional synergy of each component.
Researchers have used one-step grafting of polymer brushes to the surface of carbon-based film materials by self-initiating photo-grafting photopolymerization (SIPGP) using initiator-based catalysts by utilizing photoactive groups on the surface of carbon-based materials. A series of two-dimensional Janus thin film materials have been constructed, such as the transfer of photoactive sulfonium methylamine molecules to the surface of large-area graphene via microcontact printing technology, and amplification of SIPGP to obtain polymer-brush grafted graphene films (Chem. Commun. , 2013, 49, 11167), using graphene oxide's own photoactivity and transferability to achieve polymer brush grafting of graphene oxide films (Chem. Commun., 2014, 50, 7103), through SIPGP technology, grafting Polymer brushes are applied on one side and both sides of suction-filtered CNTs film (J. Mater. Chem. A, 2014, 2, 15268, ACS Appl. Mater. Interfaces, 2014, 6, 16204), and polymer brushes Grafting onto interface self-assembled graphene oxide/chitosan composite films (RSC Adv., 2014, 4, 22759).
The polymer-brushed unidirectionally grafted carbon-based film materials provide two-dimensional Janus film materials with new ideas in the aspects of the corresponding composition, morphology and chemical composition strictly distinguishing and finely regulating the microstructure.
Carbon nanotubes have excellent electrical properties, but their dispersion is difficult and it is more difficult to carry out micropatterned network structures. The researchers used graphene oxide to disperse the carbon nanotubes to obtain a uniform solution. This solution was used as an "ink" to prepare a patterned conductive network structure by microcontact printing, and the single-side grafted polymer brush was induced under UV light. A carbon-based thin film material having a Janus structure was obtained. The upper and lower surfaces of the Janus ultrathin film material prepared have the physicochemical properties of the polymer and the excellent electrical conductivity of the carbon nanotubes, which lays the foundation for further intelligent and synergistic application of the carbon-based hybrid material (Adv. Funct. Mater., 2015 , DOI: 10.1002/adfm.201404624).
The above results provide new ideas for the collaborative application and intelligent response of carbon-based hybrid materials. The research work was supported by the national youth thousands plan, the National Natural Science Foundation of China (51303195, 21304105), the Zhejiang Outstanding Youth Fund (LR14B040001) and the Ningbo Natural Science Foundation (2014A610127).
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