Direct CVD Growth of Multi-Layered Graphene Closed Shells around Alumina Nanofibers

Abstract

In this work, a catalyst-free direct deposition of multi-layered graphene closed shells around highly aligned alumina nanofibers with aspect ratio of 107 is demonstrated for the first time. A single – step chemical vapor deposition process of specified parameters was used for development of hybrid structures of carbon shells around the core alumina nanofibers. Transmission electron microscopy and Raman spectroscopy were used to confirm formation of graphene layers and to understand the morphology of the various structures. The developed routine for growth of peculiar carbon nanostructures opens new opportunities for deposition of the tailored carbon structures on dielectric substrates.

Thermal Transport and Thermoelectric Effect in Composites of Alumina and Graphene-Augmented Alumina Nanofibers

“…As the matrix, commercially available α-alumina nano-powder with an average particle size of 100 nm (TM-DAR, Taimei, Tokyo, Japan) was used. As nanofillers, GAIN fibers produced with the help of a cost-effective catalyst-free CVD method of carbon deposition onto ceramic nanostructures as detailed in [ 20 , 21 ] were considered. GAIN fibers were crushed in a mortar, dispersed in ethanol, and sonicated using a sonication rod (Hielscher UP400S, Hielscher Ultrasonics, Teltow, Germany) for 20 min at 30 W using the alternative regime of 4 s ON—1 s OFF, and dried in a muffle furnace following the procedure detailed in [ 22 ].…”

Graphene-Augmented Nanofiber Scaffolds Trigger Gene Expression Switching of Four Cancer Cell Types

“…Graphene on the nanofibers was augmented to the underlying oxide fiber surface during the manufacturing process and was not functionalized in any way. 34 Two types of the GAIN scaffolds were made. The C3 type is based on ∼40 nm diameter alumina nanofibers with augmented graphene coating to 10–15 nm ( Figure 1 ).…”

“…For this study, we applied additional modification of the nanofibers surface using graphene deposition. 34 …”

Hybrid graphene–ceramic nanofibre network for spontaneous neural differentiation of stem cells

“…Recently, we have demonstrated novel, grapheneaugmented inorganic nanofibre (GAIN) scaffolds capable of mimicking ECM providing highly anisotropic environment combined with oriented porosity [29][30][31], guiding cells to line up along the longitudinal axis of the fibres with a spindle-like shape and more than usually elongated cytoplasmic lamellipodia extensions. These GAIN scaffolds do not impede the normal growth of MSCs, whose oriented morphology indicates cell polarization for the preference of a specific differentiation [29].…”

“…The unique self-assembled metal oxide fibre network with an average single fibre diameter of approximately 40 nm and length of 2-10 cm with 85 -95% oriented porosity was produced using a bottom-up approach of controlled liquidphase oxidation [30,31]. These substrates were used for graphene shell growth in a single-step process of novel catalyst-free chemical vapour deposition (CVD) at 10008C at ambient pressure in a mixture of N 2 þ CH 4 gases (figure 1) [29,30].…”