Prof. Jiaxing Huang, Northwestern University
April 21, 2011
11:00 AM - 12:00 PM
810 South Clinton Street, Chicago, IL 60612
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Graphene Oxide as Colloidal Surfactant: Some New Insights into an old Material
Graphite oxide sheet, now named as graphene oxide (GO), is the product of chemical exfoliation of graphite that has been known for more than a century. Interest in this old material has resurged with the rapid development of graphene since 2004, as GO is considered to be a promising precursor for bulk production of graphene. We view GO as an unconventional type of soft material (i.e., polymers, membranes, colloids, liquid crystal and amphiphiles), and aim to establish the assembly-microstructure-properties relationship of these atomically thin sheets.
I will present some new insights into the synthesis, processing, characterization and solution properties of this old material. For example, GO is a known flame retardant for polymers, but it can turn into a serious fire hazard if improperly processed. GO is much more transparent than graphene and therefore even harder to see under optical microscope, but it can be readily visualized by fluorescence quenching microscopy. GO has long been described as hydrophilic due to its ionizable edge functional groups, however, it should be amphiphilic since there are also hydrophobic graphitic nano domains in its basal plane. As the “world’s thinnest bar of soap”, GO shows some intriguing size dependent solution properties, and can act as dispersing agent for insoluble materials in water. Some exciting opportunities and new materials created by this novel sheet-like surfactant, such as a photovoltaic fullerene/nanotube/graphene composite will be presented.
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