doug adamson, a professor of chemistry at the university of connecticut (storrs), has patented a proprietary process for manufacturing graphene in its purest form to enhance the thermal, mechanical, and electrical properties of the material, according to a report from the university.
uconn chemistry professor doug adamson has found an inexpensive way to manufacture
the pristine form of this substance, which is stronger than steel and thinner than
a human hair. (peter morenus/uconn photo)
as the article explained, most graphene that is used in research is actually graphene oxide that uses oxygen as a “chemical handle” to make the material easier to work with.
uconn researchers used a “thermodynamically-driven” approach to unstack graphite into graphene sheets and arrange the sheets into “continuous, electrically conductive” 3-d structures.
adamson told uconn today, “the simplicity of our approach is in stark contrast to current techniques used to exfoliate graphite that rely on aggressive oxidation or high-energy mixing or sonication – the application of sound energy to separate particles – for extended periods of time. as straightforward as our process is, no one else had reported it. we proved it works.”
because graphene is insoluble, adamson and his team placed graphite at the interface of water and oil and the graphene sheets spontaneously spread to cover the interface, which lowered the energy of the system and trapped the individual, overlapping sheets. they were then locked in place with cross-linked polymer or plastic.
the article added, “while stabilized graphene composite materials have countless potential uses in fields as varied as aircrafts, electronics, and biotechnology, adamson chose to apply his technology to improving standard methods for the desalination of brackish water. with his spark funding, he is developing a device that uses his graphene nanocomposite materials to remove salt from water through a process called capacitive deionization, or cdi.”
the researchers have formed a startup, 2d materials technologies, to continue working on the technology.
the research was published in acs nano in 2013. the abstract from the report stated:
“graphite’s insolubility in conventional solvents is a major obstacle to its utilization. this challenge is typically addressed by chemical modification such as oxidation, followed by reduction. however, pristine graphene possesses superior properties as oxidation and reduction lead to degradation of the graphene.
“here we demonstrate the use of an interfacial trapping technique to assemble laterally macroscopic films of pristine graphene that are up to 95% transparent. this is accomplished by modest sonication of natural flake graphite in a water/heptane mixture to form continuous films at the interface between two immiscible liquids.
“furthermore, the graphene sheets readily climb hydrophilic solid substrates, forming a homogeneous thin film one to four layers thick. these films are composed of a network of overlapping graphene sheets and shown to have long-range structure with conductivities on the order of 400 s/cm.”