Graphene–Multilayer Graphene Nanocomposites as Highly Efficient Thermal Interface Materials

Abstract

We found that an optimized mixture of graphene and multilayer graphene -produced by the high-yield inexpensive liquid-phase-exfoliation technique -can lead to an extremely strong enhancement of the cross-plane thermal conductivity K of the composite. The "laser flash" measurements revealed a record-high enhancement of K by 2300 % in the graphene-based polymer at the filler loading fraction f =10 vol. %. It was determined that a relatively high concentration of single-layer and bilayer graphene flakes (~10-15%) present simultaneously with thicker multilayers of large lateral size (~ 1 m) were essential for the observed unusual K enhancement. The thermal conductivity of a commercial thermal grease was increased from an initial value of ~5.8 W/mK to K=14 W/mK at the small loading f=2%, which preserved all mechanical properties of the hybrid. Our modeling results suggest that graphene -multilayer graphene nanocomposite used as the thermal interface material outperforms those with carbon nanotubes or metal nanoparticles owing to graphene's aspect ratio and lower Kapitza resistance at the graphene -matrix interface.

Graphene-philic surfactants for nanocomposites in latex technology

“…Studies have reported that surfactants can mediate filler-polymer interactions and enhance the filler-tomatrix transfer properties [42,44,69,70,78], though different conclusions were reached.…”

“…The more efficient CNTs are also much more expensive, and the use of graphene potentially allows for comparable enhancement of physical properties at a fraction of the cost [27,78].…”

“…All of these results would surely meet industrial needs for advancing the routes in developing high performance light weight polymer composites (low graphene content) for aircraft components, thermally conductive supports for thermal management in electronic devices and engineering applications such as antistatic and electromagnetic interference [42,78,170].…”

Generalized Two-Temperature Model for Coupled Phonons in Nanosized Graphene

“…The first one is the high interfacial thermal resistance between graphene and matrix materials 2,10 . Recent investigation showed that the interfacial thermal resistance could be overcome by alignment arrangement of graphene in composites 6 .…”

Thermal conductivity enhancement of laser induced graphene foam upon P3HT infiltration

“…1 "Softness" (or the ability to deform under pressure) allows TIMs to fill in surface roughness crevices and improve the effective heat transfer between substrates; however, soft materials with high thermal conductivity are difficult to manufacture due to the low intrinsic thermal conductivity of polymers, typically between 0.1 and 0.5 W/m-K 2 (with the exception of recent efforts to increase the thermal conductivity of pure polymer, where up to 1.5 W/m-K has been achieved using engineered interchain, heat conducting bonds 3 ). To overcome this challenge, commercial TIM manufacturers and academic researchers generally fill the polymer matrix with thermally conductive particles such as boron nitride or aluminum oxide particles (for electrically insulating applications) 4,5 or various forms of carbon such as carbon fibers, 6 carbon nanotubes, 7 and graphene flakes 8 and metals including Ag 9 (for applications where electrical isolation is less critical). Although the aforementioned filler particles exhibit large thermal conductivities, the effective increase in composite thermal conductivity can be low because of poor particle dispersion and contact resistance, which includes both phonon scattering at the polymer matrix and filler particle interface and voiding or incomplete wetting of the particle surface.…”