Bioinspired surfaces with strong water adhesion from electrodeposited poly(thieno[3,4-b]thiophene) with various branched alkyl chains

Abstract

In this original work, we wanted to prepare surfaces with both high hydrophobicity and strong water adhesion, as observed on rose petals or gecko foot. The surfaces are prepared by electropolymerization and using thieno [3,4-b]thiophene monomers with various branched alkyl chains. It is observed a change from structured to smooth when the branched alkyl chain length increases. Using short branched alkyl chains, the surfaces are mainly composed of wrinkles and nanoparticles displaying high hydrophobicity (w up to 134.9°) combined with strong water adhesion, as observed on rose petals. Indeed, dynamic contact angle measurements show that the real water adhesion can be very different even if apparent contact angle is the same. By adding H2O in the solvent (CH2Cl2 + H2O), it is possible to release gas bubbles (H2 and/or O2) in-situ leading to more porous surfaces but here it is observed an increase in surface hydrophilicity. These original polymer surfaces have potential applications in water harvesting systems or oil/water separation membranes, for example.

Highly conjugated carbazole-based monomers for the control of nanotubular surface structures by soft template electropolymerization

“…The reduction wave around -0.5 V/SCE that is quite always visible on the CV curves and especially in solvent CH2Cl2+H2O corresponds to the water traces reduction [35]. The water oxidation is not as much visible because it occurs at higher voltage around 2.5 V/SCE.…”