title: Template-free assembly of three-dimensional networks of graphene hollow spheres at the water/toluene interface.
abstract: OBJECTIVE
  The Pickering emulsion system, generated by amphiphilic graphene oxide (GO) sheets trapped between water/toluene liquid interfaces, can be directly used for template-free formation of three-dimensional (3D) structure of GO hollow spheres.
  
  
  METHODS
  The method involves the formation of highly stable micron-sized Pickering emulsions via mild sonication of GO aqueous solution and toluene in the presence of polyvinyl alcohol (PVA), followed by direct freeze-drying of the mixture for preserving the unique 3D hollow spherical structures.
  
  
  RESULTS
  The 3D structure of interconnected GO hollow spheres, with a diameter in the range ∼2 to 10 μm, has been prepared. Transmission and scanning electron microscopy analyses confirmed the formation of the 3D structure directly from the Pickering emulsion system. The presence of PVA is critical in supporting the GO hollow spherical structures. Raman analysis confirmed the structural integrity of the GO in the 3D products.
authors.affiliation: Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA 5042, Australia. Electronic address: xianjue.chen@flinders.edu.au.
authors.forename: Xianjue
authors.initials: X
authors.lastname: Chen
authors.affiliation: Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA 5042, Australia. Electronic address: paul.eggers@flinders.edu.au.
authors.forename: Paul K
authors.initials: PK
authors.lastname: Eggers
authors.affiliation: Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA 5042, Australia. Electronic address: ashley.slattery@flinders.edu.au.
authors.forename: Ashley D
authors.initials: AD
authors.lastname: Slattery
authors.affiliation: Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA 5042, Australia. Electronic address: sam.ogden@flinders.edu.au.
authors.forename: Sam G
authors.initials: SG
authors.lastname: Ogden
authors.affiliation: Centre for Nanoscale Science and Technology, School of Chemical and Physical Sciences, Flinders University, Bedford Park, SA 5042, Australia. Electronic address: colin.raston@flinders.edu.au.
authors.forename: Colin L
authors.initials: CL
authors.lastname: Raston
keywords: Freeze-drying; Graphene; Hollow spheres; Liquid interface assembly; Probe sonication; Three-dimensional materials