Superhydrophobic and Electroconductive Carbon Nanotube-Fluorinated Acrylic Copolymer Nanocomposites from Emulsions

I.S. Bayer, A. Steele, E. Loth
Italian Institute of Technology, IT

Keywords: superhydrophobic, contact angle, carbon nanotubes, conductive coatings

Summary:

It is shown that when short multi-walled carbon nanotube (MWCNT) dispersed methanol-toluene mixtures including the azeotrope are mixed with an aqueous fluoroacrylic copolymer latex dispersion, stable and surfactant free MWCNT suspended polymer emulsions can be prepared. These emulsions are sprayed on various surfaces such as glass, paper and metals to form electrically conductive polymer nanocomposite coatings. Thermal curing of the spray-cast films slightly above the melting point of the fluorinated acrylic latex, transforms them into superhydrophobic films with high static water contact angles and low droplet roll-off angles. The nanocomposites are robust against impacting liquid streams. Superhydrophobicity of the nanocomposites can even withstand water hammering with impact speeds close to 7 m/s. The nanocomposites remain electrically conductive at all times even after conversion into superhydrophobic state either by thermal curing or by flame treatment with an electrical conductivity of 25 S/m. The ohmic conductivity shows superior resistance against electrical hysteresis resulting from long delay times during repeated bias sweeps. The ease of preparation and stable ohmic electrical properties of these coatings can make them very suitable for applications such as corrosion protection for metal surfaces, conductive electrode materials for electrochemical energy conversion devices and lab-on-a-chip systems.