Superhydrophobic hollow spheres by electrodeposition of fluorinated poly(3,4-ethylenedithiopyrrole)

Abstract

Here, we report for the first time the possibility of obtaining hollow spheres in one pot by electrodeposition of fluorinated poly(3,4-ethylenedithiopyrrole)s. From synthetic pathway to elaborate heterocyclic core (eight steps), we report the synthesis of 2-(2H-[1,4]dithiino[2,3-c]pyrrol-6(3H)-yl)ethanol, also named N-(2-hydroxyethyl)-3,4-ethylenedithiopyrrole, as a new platform molecule to build up conductive materials. From this synthon, fluorinated (F-octyl, F-hexyl and F-butyl) 3,4-ethylenedithiopyrrole derivatives are synthesized and used as monomers for electrodeposition experiments. Their characterization by cyclic voltammetry reveals that the conjugation length is very short due to the presence of two sulfur atoms at the 3- and 4-positions of pyrrole. The films display superhydrophobic properties with relatively low hysteresis and sliding angle. The surface morphology consists of assembly of spherical particles. The mean size of the particles as well as the possibility of forming hollow structures increases as the fluorinated chain length decreases. The use of theoretical nucleation and growth mechanisms models reveals that a progressive three-dimensional growth as well as the relative solubility of the polymers (short polymer chains and short fluorinated tails) seem to be the determining parameters in the formation of hollow structures.