Superhydrophobic and electroconductive carbon nanotube-fluorinated acrylic copolymer nanocomposites from emulsions

[Display omitted] ► Electro-conductive nanocomposite coatings from MWCNT stabilized emulsions. ► Facile, rapid method with thermally tunable hydrophobicity. ► Application of flame treatment to form superhydrophobicity on nanocomposites. ► Remarkable resistance against high velocity impinging liquid streams (7m/s). ► Extremely stable ohmic electrical conductivity against repeated bias. 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 (Capstone ST-100), 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 static water contact angles exceeding 150°. Alternatively, thermal treatment by impinging flame heating by small diffusion flames for a few seconds, also transforms the films into superhydrophobic state with very high static water contact angles exceeding 165° and very low droplet roll-off angles less than 5°. During this process, amorphous carbon nanobeads are deposited on the nanocomposite surfaces changing their surface topology. Superhydrophobicity of the flame treated nanocomposites can even withstand water hammering from impacting liquid streams with impact speeds close to 7m/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 25S/m. The ohmic conductivity shows superior resistance against 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.