Liquid Crystal Interface Engineering Enhances Thermal Conduction for Efficient Thermal Management

Abstract

High-power integrated electronics demand heat-dissipation materials with high thermal conductivity, flexibility, and thermal stability. Herein, a liquid crystal (LC)-modified graphene interface engineering strategy is developed to fabricate aramid composite films. The polycyclic aromatic LC anchors onto graphene via strong π–π interactions, as confirmed by density functional theory. This modification improves interfacial compatibility between graphene and aramid without damaging the graphene lattice. Molecular dynamics simulations reveal that the LC interlayer effectively suppresses the interfacial thermal resistance (ITR), as the LC molecules facilitate enhanced frequency matching and vibrational mode coupling between the graphene and aramid networks. Benefiting from the ordered flow characteristics of the LC under hot pressing, the defects and gaps at the interface can be filled, forming ordered and dense thermal conduction pathways. The composite film achieves a maximum in-plane thermal conductivity of 15.39 W·m–1·K–1 at 40 wt % liquid crystal-modified graphene (LC-graphene) loading, which is 6.36 times that of a pure aramid nanofiber (ANF) film. Moreover, the film exhibits outstanding thermal stability with an initial decomposition temperature above 450 °C and mechanical properties with tensile strength reaching 101 MPa. As a heat dissipation material, it reduces the operating temperature of circuit and high-power LEDs by ∼25 °C compared to commercial pads. This work provides a promising interface design strategy for aramid-based thermal management composites.