Ordered Alignment of 2d Heterogeneous Filler for Enhancing Anisotropic Thermal Conduction Capability of Multifunctional Composite

Abstract

Anisotropic composites is highly favorable for thermal management issues. Shear stress-assisted alignment is an important Strategy for preparing anisotropic composites filled with anisotropic fillers. However, it is still a challenge to orient some quasi-spherical or spherical fillers. In this work, AlN particles were anchored on the modified graphene (S-GNS) by electrostatic assembly to construct a 2D heterogeneous filler (S-GNS@AlN), followed by compounding with PVDF via solution blending. The composite was compressed into thin sheets and molded through multilayer stacking compression to obtain an anisotropic thermally conductive composite (PVDF/S-GNS@AlN). The engineered interface between S-GNS and AlN enables synergistic thermal transport, forming a dual thermal conduction network. While the embedded 2D fillers can be effectively aligned through shear thinning during the multilayer stacking compression molding process. The composite presents an anisotropic thermal conductivity (λ), its λ∥ and λ⊥ reach 2.3 and 0.7 W/(m·K) respectively, representing a 136% improvement in λ∥/λ⊥ over that of the composite prepared by one-step compression molding. Otherwise, the composite also shows an electromagnetic interference (EMI) shielding performance of 22.7 dB at 1.95 mm. This work provides new insights into the orientation of quasi-spherical or spherical fillers in polymer-based composites, presenting a promising multifunctional material in electronic systems.

Keywords: AlN, 2D heterogeneous filler, Electrostatic assembly, Shear stress-assisted alignment, Anisotropic thermally conductive composite