Tuning the wetting properties of multiwalled carbon nanotubes by surface functionalization

A simple strategy of chemical functionalization is employed here for controlling the wettability of multiwalled carbon nanotube films from superhydorphobic (156 degrees) to nearly hydrophilic (40 degrees), which further shows superhydrophilicity with a water contact angle of about 0 degrees within 2 s. The hydrophobic surface (water contact angle 145 degrees) in case of nitric-acid-treated MWCNT bucky paper shows an unusual pinning action even at a tilt angle of 45 degrees, following Wenzel behavior of the surface. The variation in the wetting properties of MWCNT bucky paper using such surface designing strategies provides controlled heterogeneity on the surface with no or minimal effect on surface roughness.