High Thermal Conductivity of Sandwich‐Structured Flexible Thermal Interface Materials

Abstract

Thermal interfaces are vital for effective thermal management in modern electronics, especially in the emerging fields of flexible electronics and soft robotics that impose requirements for interface materials to be soft and flexible in addition to having high thermal performance. Here, a novel sandwich‐structured thermal interface material (TIM) is developed that simultaneously possesses record‐low thermal resistance and high flexibility. Frequency‐domain thermoreflectance (FDTR) is employed to investigate the overall thermal performance of the sandwich structure. As the core of this sandwich, a vertically aligned copper nanowire (CuNW) array preserves its high intrinsic thermal conductivity, which is further enhanced by 60% via a thick 3D graphene (3DG) coating. The thin copper layers on the top and bottom play the critical roles in protecting the nanowires during device assembly. Through the bottom‐up fabrication process, excellent contacts between the graphene‐coated CuNWs and the top/bottom layer are realized, leading to minimal interfacial resistance. In total, the thermal resistance of the sandwich is determined as low as ~0.23 mm2 K W−1. This work investigates a new generation of flexible thermal interface materials with an ultralow thermal resistance, which therefore renders the great promise for advanced thermal management in a wide variety of electronics.

Molecular perspective and engineering of thermal transport and thermoelectricity in polymers

“…109 Notably, the method results in a bulk-scale thermal interface material comprised of axial nanoscale bers exhibiting improved thermal conductivity. 249 5.2.5 Electrospinning. This method applies a high voltage between a sharp conductor-oen a syringe needle containing a polymer solution-and a grounded collector.…”

“…109 Notably, the method results in a bulk-scale thermal interface material comprised of axial nanoscale fibers exhibiting improved thermal conductivity. 249…”

Patterned liquid metal embedded in brush-shaped polymers for dynamic thermal management

“…Nonetheless, this approach comes with a notable drawback as it significantly compromises the mechanical properties and stability of the material, particularly in terms of excellent elasticity and softness. While progress has been made in enhancing thermal conductivity and regulating elasticity by altering the polymer matrix, [16][17][18][19] filler types, 8,15,20 and micro-composite structures, 21,22 the current thermal conductivity and soft elasticity of these materials still fall short of meeting the efficient thermal management requirements for dynamic interfaces.…”

Sandwich-Structured Thermal Interface Materials with High Thermal Conductivity

“…Traditional heat dissipation methods are no longer sufficient to meet the heat dissipation needs of high-power devices. Therefore, exploring thermal interface materials (TIMs) with high thermal conductivity has become crucial. − Ideal TIM materials require good mechanical properties to match the inherent surface roughness and maintain good contact of heater and heat sink during thermal cycling along with excellent heat transfer performance. − Polymer-based materials are widely used in TIMs due to their excellent mechanical properties and processability. However, their thermal conductivity is low and unstable at high temperatures, which has led to the development of alternative methods to enhance the performance of the high polymer matrix-based TIMs by adding high thermal conductivity materials, such as metal (Al, Ag, and Cu), ceramic (Al 2 O 3 , BN, and SiC , ), and carbon-based fillers (diamond, carbon fiber, − and graphene − …”