Thermal Interface Material with Curved Nano-Sheet Stacking
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Solution Overview
Problem
Traditional thermal interface materials struggle to achieve high thermal conductivity while maintaining compressibility, as the anisotropic properties of carbon nanomaterials like graphene and carbon nanotubes are not efficiently utilized due to random distribution and structural limitations, leading to high interfacial resistance and poor practical application.
Innovation Solution
A thermal interface material is developed by processing a laminated structure using a modulus mismatch principle, where two-dimensional high-thermal-conductivity nano-sheets on the surface have a horizontal stack structure, and those in the intermediate part have both vertical and curved stack structures, allowing for enhanced thermal conductivity and compressibility through bending, folding, and high-temperature treatment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If carbon nanotubes and graphene are randomly distributed into a polymer matrix, then the thermal conductivity is improved to 1-5 W/mK, but the anisotropic thermal conductivity property is not utilized effectively and the longitudinal thermal conductivity cannot exceed 10 W/mK
Solution Approach 1:
The patent transitions from random 3D distribution to a structured 2D laminated configuration with controlled stacking. By arranging graphene and carbon nanotube layers in specific orientations (horizontal stacking with vertical and curved arrangements in intermediate layers), the anisotropic thermal conductivity is effectively utilized, achieving longitudinal thermal conductivity of 10-600 W/mK while maintaining manufacturability through lamination processes.
Solution Approach 2:
The patent creates a multi-layer composite structure combining different carbon-based materials (graphene, carbon nanotubes) with polymer matrices. This composite approach leverages the complementary anisotropic thermal properties of each material layer, where graphene provides in-plane conductivity and carbon nanotubes provide through-thickness conductivity, achieving superior overall thermal performance compared to single-material systems.
2Temperature
If vertical carbon nanotube structure is prepared by CVD, then the longitudinal thermal conductivity exceeds 30 W/mK, but the interfacial thermal resistance is high (30-70 Kmm2/W) and the apparent density is difficult to improve
Solution Approach 1:
The patent combines vertical carbon nanotube layers with graphene layers and polymer matrices in a laminated composite structure. This composite approach reduces the effective interfacial thermal resistance by providing multiple parallel heat conduction pathways through graphene's high in-plane conductivity and the polymer matrix's thermal coupling, while maintaining the high longitudinal conductivity contribution from vertical nanotubes.
Solution Approach 2:
The patent introduces horizontal graphene layers and curved intermediate structures between vertical carbon nanotube layers, creating a multi-dimensional heat conduction network. This dimensional transition from purely vertical to combined vertical-horizontal-curved pathways reduces thermal bottlenecks and interfacial resistance while enhancing overall thermal conductivity.
3Temperature
If vertical graphene structure is prepared by CVD on aluminum nitride matrix, then the thermal conductivity reaches up to 80 W/mK, but the structure is difficult to peel from the matrix which severely limits practical application
Solution Approach 1:
The patent segments the thermal interface material into a self-contained laminated structure where vertical graphene is integrated within multiple layers (graphene, carbon nanotube, polymer) rather than being a separate CVD-grown structure on an external substrate. This segmentation eliminates the peeling problem by making the vertical graphene an integral part of a freestanding composite material that can be directly applied.
Solution Approach 2:
The patent embeds vertical graphene structures within a multi-layer composite matrix comprising polymer, graphene, and carbon nanotube layers. This composite approach provides mechanical support and thermal coupling while enabling the vertical graphene to function effectively without requiring peeling from a CVD substrate, thus solving the practical application limitation.
4Temperature
If graphene paper is rolled up and sliced vertically to prepare thermal interface material, then the thermal conductivity reaches up to 600 W/mK, but the elastic modulus is up to 500 Mpa making it non-compressible and unable to cope with chip tolerance
Solution Approach 1:
The patent applies local quality by creating a laminated structure with different layer characteristics: rigid vertical graphene/carbon nanotube layers provide high thermal conductivity, while polymer matrix layers provide compressibility and flexibility. This local differentiation of material properties within the composite enables simultaneous achievement of high thermal performance and mechanical compliance for chip tolerance.
Solution Approach 2:
The patent creates a composite material system combining rigid carbon-based thermal conduction layers with compliant polymer matrix layers. This composite structure reconciles the contradiction between high thermal conductivity (from rigid carbon layers) and compressibility (from polymer layers), enabling the material to maintain chip contact under thermal expansion and mechanical stress.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The material achieves a longitudinal thermal conductivity of 10-600 W/mK with a compression ratio of 5-80%, enabling effective heat dissipation and flexibility, suitable for high-temperature and corrosive environments, with a simple, cost-effective, and environmentally friendly preparation method.
Implementation Method 1
two-dimensional high-thermal-conductivity nano-sheets on the upper surface and the lower surface of the thermal interface material have a horizontal stack structure, and two-dimensional high-thermal-conductivity nano-sheets located in intermediate part between the upper surface and the lower surface of the thermal interface material have both a vertical stack structure and a curved stack structure
Implementation Method 2
processing the laminated structure based on a modulus mismatch principle, thereby obtaining a folded laminated structure; b-3) pressing the folded laminated structure at a first pressure in horizontal direction of the folded laminated structure, and then annealing for a first time period at a first temperature
Data Source
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AI summary
The present invention relates to a thermal interface material, and preparation and application thereof. Specifically, disclosed in a thermal interface material. The thermal interface material is obtained by bending and folding, optional horizontal pressing and optional high-temperature treatment of a laminated structure. Two-dimensional high-thermal-conductivity nano-plates on the upper surface and the lower surface of the thermal interface material have a horizontal stack structure. Two-dimensional high-thermal-conductivity nano-sheets located between the upper surface and the lower surface of the thermal interface material have both a vertical stack structure and a curved stack structure. Also disclosed are a preparation method and application of the thermal interface material. The thermal interface material combines excellent thermal conductivity and compressibility; the preparation method has the characteristics of simple process, low costs, safety and environmental protection, and accordingly, the thermal interface material can effectively resolve the heat dissipation problem of electronic products.