CNTs in Thermal Interface Materials – Heat Dissipation Applications
For engineers, product developers, and small–medium overseas buyers evaluating advanced carbon-based thermal materials
Thermal Interface Materials (TIMs) play a critical role in electronics, power modules, EV batteries, and LED systems. As power density increases, traditional fillers such as alumina, BN, or graphite powder are gradually reaching performance limits—especially when customers need both high thermal conductivity and mechanical flexibility.
Carbon nanotubes (CNTs) offer a unique solution. Because of their exceptional intrinsic thermal conductivity (2,000–3,000 W/m·K), high aspect ratio, and ability to form efficient percolation networks, CNT-enhanced TIMs can significantly improve heat dissipation performance across various packaging and assembly structures.
This article explains how CNTs improve TIM performance, how they are integrated into different TIM formats, and what engineers should consider when selecting CNT-based solutions.
1. Why CNTs Are Effective in TIMs
CNTs bring several key advantages to thermal interface materials:
1.1 Ultra-High Intrinsic Thermal Conductivity
• Multi-wall CNTs (MWCNTs): typically 1,000–3,000 W/m·K
• Single-wall CNTs (SWCNTs): can exceed 3,000 W/m·K
Even at low loading, CNTs contribute to a highly connected heat-spreading network.
1.2 High Aspect Ratio for Efficient Heat Pathways
CNTs naturally bridge micro-gaps inside the polymer matrix, forming continuous thermal channels that outperform spherical or plate-like fillers.
1.3 Strong Interfacial Coupling (After Functionalization)
Functionalized CNTs (carboxyl, hydroxyl, amine) bond more effectively with silicone or epoxy matrices, reducing thermal interfacial resistance.
1.4 Low Loading for High Performance
CNTs can reach meaningful conductivity improvements at <3 wt%, compared to 40–80 wt% for ceramic fillers.
This supports applications that require low viscosity, flexibility, or thin-film TIM layers.
2. CNT Types for Thermal Interface Materials
2.1 Multi-Wall CNTs (MWCNTs)
Most common choice for TIMs:
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Good thermal and electrical conductivity
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Cost-effective
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Easier to disperse
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High mechanical strength
Best for: silicone grease, gap filler putty, thermally conductive rubber.
2.2 Single-Wall CNTs (SWCNTs)
Higher thermal performance but more expensive.
Used in: advanced aerospace modules, high-end chips, micro-TIM thin films.
2.3 Functionalized CNTs
Purpose: improve polymer compatibility and dispersion
Common forms:
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CNT-COOH
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CNT-OH
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CNT-NH₂
Ideal for epoxy TIMs and thin-layer adhesives.
2.4 CNT Networks / Buckypaper
Used when extremely low thermal resistance is required:
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High-power LEDs
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IGBT modules
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Chip-on-board (COB) assemblies
3. CNT Integration into TIM Formulations
CNT-enhanced TIMs appear in multiple commercial formats:
3.1 CNT-Enhanced Thermal Grease
• Silicone matrix + CNTs (0.5–3%)
• Additional ceramic fillers such as AlN or BN for hybrid performance
Benefits:
✓ High thermal conductivity
✓ Lower viscosity at equal performance
✓ Enhanced pump-out resistance
3.2 CNT Gap Filler (Putty-Type)
Gap fillers (1–3 mm) need to compress well and maintain structure.
CNTs increase:
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thermal pathways
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elasticity
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structural stability under compression
Common applications: EV battery modules, telecom base stations.
3.3 CNT-Modified Epoxy Adhesives
Used in structural bonding where both thermal and mechanical strength are needed. CNTs help:
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improve toughness
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reduce interfacial cracking
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enhance conductivity at low loading
3.4 CNT Films (Thin TIM Layers)
For next-generation electronics:
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vertically aligned CNT arrays
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sprayed CNT films
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CNT composite thin sheets (<50 µm)
These offer excellent thermal spreading with very low thermal resistance, ideal for chips or high-power modules.
4. Key Performance Indicators (KPIs) for CNT-Based TIMs
Customers evaluating CNT-enhanced TIMs typically focus on these KPIs:
4.1 Thermal Conductivity (Bulk)
CNT TIMs can reach:
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Silicone grease: 3–8 W/m·K (at low CNT loading)
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Epoxy adhesives: 2–6 W/m·K
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CNT films: 10–20 W/m·K (in-plane)
4.2 Thermal Resistance (Rθcs)
More important than bulk conductivity. CNT TIMs reduce:
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contact resistance
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interface gaps
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micro-void formation
4.3 Viscosity and Printability
Low CNT loading helps maintain processability for:
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dispensing
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stencil printing
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screen printing
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spraying
4.4 Mechanical Stability
CNTs improve:
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shear strength
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crack resistance
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pump-out performance
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long-term thermal cycling reliability
4.5 Electrical Conductivity
Important for some modules but not all.
CNTs can be electrically conductive, so electrical insulation is usually maintained by:
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hybrid mixing with ceramic fillers
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ultra-low CNT loading
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surface-functionalized CNTs
5. Applications of CNTs in Thermal Interface Materials
CNT-enhanced TIMs are relevant in many sectors:
5.1 Power Electronics (IGBT, MOSFET, SiC modules)
• Reduced junction temperature
• Improved reliability during thermal cycling
5.2 Electric Vehicles (EV Battery Modules)
Used between:
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cell & cooling plate
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BMS components
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power electronics
Benefits:
✓ better temperature uniformity
✓ improved safety margin
5.3 LEDs & Lighting Systems
CNT TIMs reduce:
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LED junction temperature
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lumen decay
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color shift during long-term operation
5.4 Telecom Equipment & Server Cooling
CNT TIMs fit high-power base station components:
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filters
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amplifiers
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rectifiers
Also widely used for data center modules with high heat flux.
5.5 Aerospace & Military Electronics
SWCNT-based TIMs are used for:
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radar modules
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satellite electronics
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high-G environment components
Because of high thermal conductivity + weight reduction.
6. Key Considerations for Customers Choosing CNT TIMs
When discussing with overseas buyers or engineers, highlight these points:
6.1 Dispersion Quality
Good dispersion = better conductivity.
Providers with high shear mixing / ultrasonic dispersion have advantage.
6.2 Surface Functionalization
Functionalized CNTs integrate much more efficiently with epoxy or silicone.
6.3 Hybrid Formulation Strategy
CNTs often pair with BN or AlN to balance:
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insulation
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thermal performance
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cost
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viscosity
6.4 Film vs. Paste Selection
Films suit high-precision chips.
Pastes are versatile for general industry.
6.5 Reliability Testing
Include:
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thermal cycling
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pump-out tests
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long-term aging
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squeeze-flow performance
7. What We Offer (For Overseas SME Customers)
Our CNT products for TIM applications include:
• MWCNT (industrial & high-purity)
• Functionalized CNT (COOH, OH, NH₂)
• Water-based or solvent-based CNT dispersions
• CNT-enhanced silicone/epoxy slurry (customized)
• CNT composite films & vertically aligned CNT layers
We support customers from materials selection → formulation → pilot testing, suitable for small-scale experimental batches and ramp-up to industrial supply.
Carbon nanotubes are becoming one of the most advanced fillers for thermal interface materials. Their combination of high thermal conductivity, low loading, flexibility, and strong interfacial bonding enables TIM products with significantly improved performance compared with traditional ceramic-filled systems.
As electronics continue to push power density higher, CNT-enhanced TIMs will play a key role across EVs, power electronics, data centers, aerospace, and next-generation semiconductor packaging.