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Graphene has attracted growing interest in the past few years. Growing vertically oriented graphene sheets with a designed pattern is practically attractive for device applications based on graphene. Here we report a patterned synthesis of vertical graphene nanosheets using plasma-enhanced chemical vapor deposition. Both experimental and modeling results suggest that the electric field distribution above the substrate material plays a key role in the graphene coverage. Vertical graphene patterns can thus be designed through artificially designing the surface electric field distribution. A field-effect transistor (FET) sensor device has been demonstrated for detection of low-concentration gases using vertically patterned graphene sheets bridging a metal electrode gap.

High heat conduction performance of electrical insulating composite is highly desired in thermal management of electronics. In this study, densely packed boron nitride (BN) composites with resin matrices of epoxy, polymethyl methacrylate, and an acrylic copolymer based binder were prepared through a solvent mediated mixing and compression molding method. The solvent mediated mixing assisted homogeneous dispersion; the compression molding removed excessive resin and led to alignment of BN flakes with high filler content. The resulted composites exhibited superior in‐plane thermal conductivity k// up to 21.3 W/mK and pronounced anisotropic heat conduction properties. The thermal conductivity was positively correlated with density bold-italicρ of a specimen in experimental. A presentation of thermal conductivity bold-italick=bold-italick|bold-italicρ was proposed, and the dependence of thermal conductivity on specimen density bolddbold-italicktrue(bold-italicρtrue)/bolddbold-italicρ > 0 was proven mathematically. The application of BN composite in LED thermal management was demonstrated. An epoxy/BN heat spreader was used to efficiently cool down a 0.3‐W LED. The cooling effect was close to that with Al board heat spreader. POLYM. COMPOS., 39:E1653–E1658, 2018. © 2017 Society of Plastics Engineers

A facile dry route electrostatic-force-directed assembly (ESFDA) was used to deposit silver nanocrystals onto the external surface of vertically aligned multiwalled carbon nanotubes (MWCNTs). Charged and nonagglomerated aerosol silver nanocrystals were first produced using a mini-arc plasma source. The nanocrystals were then assembled onto the electrically biased MWCNT array through the enhanced electric field near the CNT surface. The electrostatic field plays a crucial role in the assembly process. Gradients of the nanocrystal size and the nanocrystal areal density along the length of the CNT have been observed, and these are likely due to the variation of the electric field near the CNT surface. The ESFDA technique enables the in situ coating of CNT arrays with nanocrystals to create novel hybrid nanomaterials with tailored properties.

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