Seminar

Seminar

[세미나공지] 10월 1일(목)

  • POSTED DATE : 2015-10-01
  • WRITER : 관리자
  • HIT : 2971
  • DATE : 2015-10-01
  • PLACE : 화학관 330226호

안녕하세요 

 

다음주 목요일(10월 1일) 세미나 진행됩니다.               

많은 참석 부탁드립니다.

 
감사합니다.       

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제  목 :  Self-assembly of graphene oxide nanosheets induced by interfacial polyionic complexation

             

연  사 : Franklin Kim 교수 (Institute for Integrated Cell-Material Sciences, Kyoto University)

 

일  시 : 2015년 10월 1일 (목) 오후 4시 30분


장  소 : 화학관 세미나실 (330226호실)

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Self-assembly of graphene oxide nanosheets induced by interfacial polyionic complexation

       

  One of the critical challenges for the practical application of graphene and its derivatives is developing a robust and versatile assembly method which allows the construction of the nanosheets into functional macroscopic structures appropriate for integration with conventional real-life devices. An interesting characteristic of graphene oxide is that they often behave as charged macromolecules, and thus can readily interact with an oppositely charged polyelectrolyte to form a stable complex. In this report, we demonstrate how such complexation process could be utilized for directing the self-assembly of nanosheets. By confining the nanosheet-polyelectrolyte complexation at air-liquid or liquid-liquid interfaces, the nanosheets are successfully assembled into various mesoscale architectures including fibers, capsules, films, and even 3D porous foam-like structures. In particular, we introduce a novel “diffusion driven layer-by-layer” assembly and demonstrate its application for the construction of graphene oxide (GO) sheets into porous three-dimensional structures. The process utilizes the interaction of GO with branched polyethylenimine (b-PEI), a positively charged polyelectrolyte, to form a stable complex. Interestingly, when this reaction is confined at a liquid/liquid interface, we observe that the diffusion of b-PEI allows the GO/b-PEI complex formed at the interface to continuously grow into a foam-like framework with tunable porosity. Furthermore, the assembly process can be utilized in various configurations such as to create free-standing architectures with tailored shapes or patterned films on a substrate. The obtained GO structures are quite stable and can be reduced using various methods. This novel assembly method opens pathway to many useful nanosheet superstructures, and may be further extended to other types of nanomaterials in general.