Carbon nanotube grease and sustainable manufacturing

A stable and homogeneous grease based on carbon nanotubes (CNTs, single wall and multi wall) in polyalphaolefin oil has been produced without using a chemical surfactant. For example, for a 11 wt% (7 vol%) single wall CNT (diameter 1~2 nm, length 0.5-40 µm) loading, the thermal conductivity (TC) of the grease shows a 60-70% increase compared to that for no nanotube loading. In addition, the grease is electrically conductive, has a high dropping point, good temperature resistance and doesn't react with copper at temperatures up to 177ºC. The performance of carbon nanotube grease could be much better with the improvement of base oil, nanotube functionality, quality and purity. A possible explanation for these results is that for a high loading of CNTs (>10wt%), they become associated with each other by van der Waals forces in the grease to form three dimensional percolation networks. These greases could be sustainably manufactured.