Confinement effect and spreading of water into microchannels fabricated on the VACNT surfaces

An easy and fast method to produce microchannels on the vertically aligned multiwalled carbon nanotube (VACNT) surfaces is described. Alternating superhydrophilic and superhydrophobic channels were built on VACNT films, using oxygen plasma functionalization and CO2 laser treatment, respectively. A combined effect of wettability and capillary forces promotes an effective spreading, and confinement of water microdroplets on the superhydrophilic channels.

Research highlights
► This manuscript describes a method for fabrication of microchannels on multi-walled vertically aligned carbon nanotube (VACNT) films.
► Oxygen plasma etching and CO2 laser treatments creates alternating superhydrophilic and superhydrophobic channels on VACNT films.
► The water could spread onto superhydrophilic channels and kept confined between the superhydrophobic walls.
► Capillary effect was also observed.