Directional formation of microtubes by soft-template electropolymerization from fully conjugated triphenylamine-based monomers

Khady Diouf (1) , Abdoulaye Dramé (1) , Alioune Diouf (1) , François Orange (2) , Frédéric Guittard (2) , Igor F Perepichka (3) , Thierry Darmanin (2)

1 UCAD - Université Cheikh Anta Diop de Dakar [Sénégal]
2 UniCA - Université Côte d'Azur
3 Silesian University of Technology

Microtubular structures have been prepared by soft-template electropolymerization of conjugated organic monomers with the aim to mimic the strong water-adhesive forces of gecko foot or rose petals. Water-saturated solvent of low water solubility (dichloromethane) was used to form a micellar solution stabilized by tetrabutylammonium perchlorate as the electrolyte and the surfactant, in which case the formation of nanotubes was particularly efficient. The studied monomers were built from a triphenylamine core conjugated with three arms differing by their structure and positions: (i) 2-or 3positions in the thiophene arms or (ii) carbazole arms attached to para, meta or ortho-positions of the benzene ring of the core. The formation of microtubes is due to preferential growth of polymer films and an aggregation of formed polymers/oligolymers in one direction (1D) facilitated by -stacking interactions. The key factors influencing on the surface morphologies (monomer structures and reactivity, electrodeposition conditions, etc) are discussed. Impressive results have been obtained in studies of carbazole-containing monomers and the effect of regioisomerism in the monomers (the position of the carbazole attachment to the core). Extremely long microtubes (tens to >100 μm length, diameter ≈ 1.0-1.5 μm) were formed on the electrode surface from the monomer N-Ph-p-Cb with the carbazole attachment in the para-position. Wettability analysis showed highly hydrophobic surfaces with apparent contact angles up to 154.0 ° and extremely strong water adhesion comparable to rose petals or gecko feet. Such coatings can find applications in water-harvesting systems, sensing platforms or electrochemical analyses.

Mots clés: Electropolymerization; Hydrophobicity; Surface structures; Triphenylamine; Thiophene; Carbazole; Regioisomerism; Adhesion; Conjugated polymers

Domaines: Chimie

Khady Diouf, Abdoulaye Dramé, Alioune Diouf, François Orange, Frédéric Guittard, et al.. Directional formation of microtubes by soft-template electropolymerization from fully conjugated triphenylamine-based monomers. Journal of Electroanalytical Chemistry, In press. ⟨hal-04187528⟩