Temperature-dependence of wetting properties of carbon nanotubes

• By increasing the temperature, the rate of water imbibitions into CNTs improves as well.
• CNTs are more water-wet at higher temperatures.
• The wetting transition temperature for TIP3P water inside CNTs has been estimated.

We have carried out molecular dynamics simulations to study the spontaneous imbibition of water into a single-wall carbon nanotube (CNT) at various temperatures, ranging from 270 K to 370 K. The simulations indicate that by increasing the temperature, the rate of mass uptake improves as well. Considering the end-loss friction as the main source of energy dissipation and ignoring the inertial effect on the nano-scale transport, we derive a simple expression that relates the CNT’s wettability to the fluid viscosity and the rate of imbibition over the temperature range that we study. Our results also indicate that the increase in the wettability of the CNT, and the reduction in the viscosity of water at higher temperatures cause enhancement of water uptake into the nanotube. They also enable us to estimate the wetting transition temperature for TIP3P model of water in the CNTs.