As graphene's popularity grows as an advanced
Nam, an expert in the area of 2D materials, is especially interested in graphene for its use in sensors or flexible devices—for instance, a wearable patch that, when placed directly on skin, is so thin and transparent, it isn't noticeable. Nam currently has projects with industry for making wearable graphene sensors.
Graphene is synthesized by using chemical vapor deposition onto a metal substrate, typically copper foil. One particularly tricky aspect of producing graphene is how to separate this atomically thin material from its native metal substrate for integration into useful devices. This typically involves either dissolving away the high-purity metal or delaminating it from the substrate - which require the use of harsh chemicals that leave stubborn residue. The ultra-thin graphene also needs to be coated with a polymer support layer such as polycarbonate or PMMA (poly methyl methacrylate), which requires the use of often toxic and carcinogenic solvents.
"In our case, we are using a bio-mass derived polymer, ethyl cellulose, for the coating," said Michael Cai Wang, Nam's PhD student and lead researcher on the project. "A common and inexpensive polymer often used as a food additive, ethyl cellulose is solvated in just ethanol. This not only makes our graphene transfer process more environmentally friendly, it is now also compatible with a variety of polymeric and soft biological materials such as common plastics and hydrogels that would otherwise not tolerate harsh solvents."
Read more at: https://phys.org/news/2017-08-fizzy-soda-key-flat-material.html#jCp
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