Carbon nanotubes grease with high electrical conductivity

Abstract

While most commercial greases are used to prevent wear and tear in machinery, many specialized applications require electrically conductive grease. Applications include, but are not limited to, use in next generation electric vehicles (NGEVs), superb electric motor bearing protection, and electrical contact improvement. Using recently new invented methods, electrically conductive greases have been prepared. Petro-Canada N650HT oil with 7.5 wt% hydroxyl functionalized multiwall carbon nanotubes (MWNT-OH), yielded a surprising resistivity of 22.4 Ω cm, compared to the resistivity of 7880 Ω cm of an almost identical sample made with multiwall nanotube (MWNT). Another sample, 75 % Glycerol, 25 % Water, 4.5 wt% MWNT-OH, yielded the lowest resistivity of all samples measured, at 10.0 Ω cm. Hydrogen bonding is believed to be attributed to the best performing samples. The introduction of hydrogen bonding in any form into the grease increases electrical conductivity. This finding can be extended with further research to other nanomaterials with functional groups like OH, COOH, F, and NH.