Investigation of thermal energy transport interface of hybrid graphene-carbon nanotube/polyethylene nanocomposites

Enhancement of thermal energy transport across the graphene/h-BN heterostructure interface

Enhancing thermal energy transport is critical for the applications of 2-dimensional materials. Here, we explored the methods of enhancing the interfacial thermal energy transport across the graphene (GR)/hexagonal boron nitride (h-BN) heterostructure interface, and revealed the enhancement mechanisms of interfacial thermal energy transport by applying non-equilibrium molecular dynamics (NEMD) simulations. The computational results indicated that both doping and interface topography optimization could effectively improve the interfacial thermal conductance (ITC) of the GR/h-BN heterostructure. In particular, the enhancement of the zigzag interface topography led to a much better result than the other methods. Doping and interface topography optimization increased the overlap of the phonon density of states (PDOS). Temperature had a negligible effect on the ITC of the GR/h-BN heterostructure when the temperature exceeded 600 K.

Implication of thermally conductive nanodiamond-interspersed graphite nanoplatelet hybrids in thermoset composites with superior thermal management capability

Novel hybrid nanofillers composed of nanodiamond-attached graphite nanoplatelets (ND@GNPs) were designed and employed to toughen the epoxy (EP) matrix for fabricating superior thermal conductive and physically robust thermoset nanocomposites for electronics and auto industries. The hybrid nanofiller was covalently bonded by 4,4'-diphenylmethane diisocyanate and it provided distinct enhancement in thermal conductivity and dynamic storage modulus of the EP/ND@GNPs nanocomposites attributing to the unique nanostructure of ND@GNPs that can form strong interfacial interaction with EP matrix, thus restrict the EP molecular motions. The EP/ND@GNPs20 presented a thermal conductivity of 2.48 W · m^-1 · K^-1 and dynamic storage modulus of 5.6 GPa. The presence of ND particles not only can enhance heat transfer efficiency but also improve the interfacial interaction between ND and EP matrix, which can directly affect physical properties of the EP composites.

On the Generalized Thermal Conductance Characterizations of Mixed One-Dimensional-Two-Dimensional van der Waals Heterostructures and Their Implication for Pressure Sensors

The emergence of ever-growing two-dimensional (2D) materials has made revolutionary innovations on van der Waals (vdW) heterostructural designs by integrating them with other low-dimensional materials to achieve unprecedented and/or multiple functionalities that are beyond individual components. Guided by full-scale molecular dynamics simulations, we present a mixed-dimensional heterostructure by vertically stacking one-dimensional (1D) and 2D materials through noncovalent vdW interactions and demonstrate that the thermal conductance can be generalized into a unified model by incorporating their mechanical properties and geometric features. Simulation analyses further reveal the strong dependence of thermal conductance on the location and magnitude of an external pressure loading applied to the local vdW heterojunctions. The underlying thermal transport mechanism is uncovered through the elucidation of the mechanical deformation, curvature morphology, and density of atomic interactions at the heterojunctions. A proof-of-conceptual design of such a heterostructure-enabled pressure sensor is explored by utilizing the unique response of thermal transport to mechanical deformation at heterojunctions. These designs and models are expected to broaden the applications and functionalities of mixed-dimensional heterostructures and will also offer an alternative strategy to leverage thermal transport mechanisms in the design of high-performance vdW heterostructure-enabled sensors.