Graphene -- Based Nanocomposites as Highly Efficient Thermal Interface Materials

We found that an optimized mixture of graphene and multilayer graphene - produced by the high-yield inexpensive liquid-phase-exfoliation technique - can lead to an extremely strong enhancement of the cross-plane thermal conductivity K of the composite. The "laser flash" measurements revealed a record-high enhancement of K by 2300 % in the graphene-based polymer at the filler loading fraction f =10 vol. %. It was determined that a relatively high concentration of single-layer and bilayer graphene flakes (~10-15%) present simultaneously with thicker multilayers of large lateral size (~ 1 micrometer) were essential for the observed unusual K enhancement. The thermal conductivity of a commercial thermal grease was increased from an initial value of ~5.8 W/mK to K=14 W/mK at the small loading f=2%, which preserved all mechanical properties of the hybrid. Our modeling results suggest that graphene - multilayer graphene nanocomposite used as the thermal interface material outperforms those with carbon nanotubes or metal nanoparticles owing to graphene's aspect ratio and lower Kapitza resistance at the graphene - matrix interface.Comment: 4 figure

Boron nitride nanotube composites: production and properties

Boron nitride nanotubes (BNNTs) exhibit a range of properties that are as impressive as those of carbon nanotubes (CNTs), including comparable mechanical properties, but with different multifunctional advantages such as considerably higher thermal stability, polarizability, wide band gap, and high neutron absorption capability. These characteristics make BNNTs attractive for the fabrication of enhanced composites including for mechanical reinforcement, heat dissipation, high temperature composites, neutron shielding, and piezoelectric composites among other possibilities. Recent advances in large-scale production of BNNTs have resolved the supply limitation for BNNT nanocomposites research and the development of BNNT-enhanced composites is now poised to accelerate rapidly. Here we highlight the production of large-scale, composites-relevant quantities of BNNTs based on a scalable RF plasma torch method and present examples from our work on both bulk BNNT-polymer composites and nanocomposites based on BNNT sheets.Peer reviewed: YesNRC publication: Ye

Carbon nanotube modified optical fiber surface with novel coating method for non-linear and SPR application

Single-wall carbon nanotube deposition with dipping method on gold-coated plasmonic optical fiber sensors has been proposed and demonstrated. The effects of carbon nanotubes on the polarization-dependent coupling of light from the fiber to the coating and on the resulting refractometric sensor properties are experimentally investigated