Graphene-multilayer graphene nanocomposites as highly efficient thermal interface materials.
We found that the 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 the relatively high concentration of the single-layer and bilayer graphene flakes (~10-15%) present simultaneously with the thicker multilayers of large lateral size (~1 μm) were essential for the observed unusual K enhancement. The thermal conductivity of the 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.
Nano-Device Laboratory, Department of Electrical Engineering and Materials Science and Engineering Program, Bourns College of Engineering, University of California - Riverside, Riverside, California 92521, USA.
Khan M F
KM
Shahil
Alexander A
AA
Balandin
D006108:Graphite / Q000737:chemistry*; D007834:Lasers; D008567:Membranes, Artificial; D053761:Nanocomposites / Q000737:chemistry*; D010316:Particle Size; D011108:Polymers / Q000138:chemical synthesis / Q000737:chemistry; D013696:Temperature; D013814:Thermal Conductivity
D008567:Membranes, Artificial; D011108:Polymers; D006108:Graphite