pH- and voltage-switchable superhydrophobic surfaces by electro-copolymerization of EDOT derivatives containing carboxylic acids and long alkyl chains.

ABSTRACT

In order to produce pH- and voltage-switchable superhydrophobic surfaces, PEDOT derivatives containing various proportions of a EDOT monomer containing carboxylic groups (EDOT-COOH) and EDOT monomer-containing dodecyl chains (EDOT-O-H12) are elaborated. The surface morphology and roughness depend highly on the proportion of the monomers. Superhydrophobic properties are reached for a mol% of EDOT-COOH between 0 and 25%. It is possible to switch from superhydrophobic to hydrophilic (θ(water) until about 45°) by electrochemical reduction at low voltage (-1 V vs SCE) to remove the doping anions, following by treatment with NaOH to change the carboxylic groups into carboxylate. By elaborating smooth surfaces of each polymer, the effect of each treatment is reported. The reversibility of the reactions is also reported.