"Effects of dissolved gases in the dispersion of carbon nanotubes in water" by Prof. C.K. Chan

Date :      December 9^th  (Fri), 2016
Time:      3:00pm – 4:00pm
Venue:    D015, Lab1 Level D
Speaker:  Prof. C.K. Chan (Institute of Physics, Academia Sinica, Taiwan)

Title: Effects of dissolved gases in the dispersion of carbon nanotubes in water

Abstract:
Normally, carbon nano-tubes (CNT) cannot be dispersed easily in water because of the hydrophobicity of carbon surfaces. Usually, surfactants are added to form a stable CNT/Water dispersion. Here we report our experiments to explore the effects of dissolved gases in the water on the formation of CNT/water dispersion. In the experiments, multi-wall CNT are dispersed by sonification in water with and without degassing by the freeze-pump-thaw method. Contrary to the formation of stable surfactant-free dispersion of hydrophobic substance such as oil in degassed water, we find that CNT dispersions formed in degassed water are not as stable as those formed in water with dissolved gases. Further experiments with dynamic light scattering (DLS) shows that the forms of the CNT/Water dispersions are different with and without degassing. The stability of CNT/water with dissolved gases might probably be due to the formation of a gel-like structure in the CNT/Water dispersion as revealed by the DLS experiments. This last finding suggests that the dissolved gases might be acting like a cross-linker; providing physical strength needed for a gel-like structure.

We look forward to seeing many of you at the seminar.