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Carbon nanostructures such as chemically vapor deposited carbon nanotubes have shown remarkable thermal, mechanical and electrical properties, making them an area of intense scientific interest. However, their actual use in new technology has been limited by both the extreme nature of efficient growth conditions and the difficulty of conformally coating the structure while maintaining the original morphology. Carbon nanosheets (CNS) - vertically oriented nanostructures of 1-5 graphene layers - have shown promise as a more robust alternative carbon nanostructure. Previous reports have detailed the synthesis of carbon nanosheets via RF PECVD on metallic, insulating and semiconducting substrates, their characterization via Raman, XRD, SEM, TEM, FTIR, PIXE, ERDA, and TDS[1]
Here we report the conformal coatings of nanosheets with an atactic polyimide, an industrial silicone, positive and negative photo resist, and two photoactive polymers via either a customized spin-casting or by a modified drop casting procedure of the polymers. SEM shows that, at low loadings, a conformal coating of polymer on the nanosheets is produced; thicker loadings cause intercalation of the polymer between the nanosheets and a complete incorporation of the nanosheets into a solid polymer film. Tuning the deposition conditions allows for air release and eliminates void formation and thereby minimizes undercutting when patterning the nanosheets via photoresist-based techniques. Further, utilizing customized polymer incorporation, nanosheets have been transferred to alternative substrates, while maintaining the original morphology. The ability to transfer nanosheets to a substrate that need not take on the thermal budget of the carbon nanostructure synthesis combined with the ability to pattern nanosheets using standard photoresist techniques offers the potential for an enabling technology for more realistic nanosheet-based devices and sensors.
1. French, B.L., et al., Journal of Applied Physics, 2005. 97(11): p. 114317 and references 3, 4 and 5 therein.
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