Water vapor adsorption onto nanostructured carbide derived carbon (CDC)

Carbide derived carbon, CDC, is a layer synthesized by the selective etching of a metal from a metal carbide. The resulting carbon material that remains is a layer with several unique and useful properties. Properties of CDC are the low friction coefficient of CDC, the high specific surface area of CDC, and the tunable porosity of CDC. Although these properties have been well studied, there has not been much work done into looking the affect that adsorbed water plays on properties of CDC. It is important to understand the affect of water has on CDC since CDC will be used in atmospheric conditions where it will be constantly exposed to water vapor, in the form of humidity in the environment. To test the effect that water has on CDC, samples were synthesized under a variety of different conditions. Once the samples were synthesized, they were placed in controlled humidity environments. The amount of water adsorbed was determined and the resulting isotherms were plotted. The isotherms showed that chlorinated CDC has a microporous structure. However CDC that was post-treated in either a hydrogen gas blend or high purity argon gas has structure that contained mesopores. The post-treated results also show that the friction coefficient of CDC increases when it is annealed in an inert environment at elevated temperatures. Finally contrary to previous work, residual chlorine in the CDC does not play a role in the friction coefficient of CDC.