Designing bioinspired coral-like structures using a templateless electropolymerization approach with a high water content.

Here, with the aim of obtaining densely packed porous nanostructures of various shape using templateless electropolymerization in organic solvent (dichloromethane), original thieno[3,4- b]thiophene-based monomers with different substituents are studied. First of all, the adding of water in solution has a huge influence on the formation of porous structures because a much higher amount of gas (O2 and/or H2) is released. Rigid substituents such as aromatic groups have a beneficial effect on the formation of nanotubular structures contrary to flexible ones such as alkyl chains. Special results are obtained with the pyrene substituent (Thieno-Pyr). With this monomer, coral-like structures are obtained. These structures are obtained by the formation first on long nanotubular structures and their sagging due to their weight. Then, the released gas is trapped inside these structures leading to huge craters. These exceptional surfaces could be used in the future in various potential applications such as in drug delivery, cell growth, sensors, optical devices or surface adhesion. This article is part of the theme issue 'Bioinspired materials and surfaces for green science and technology (part 2)'.

Parahydrophobic and Nanostructured Poly(3,4-ethylenedioxypyrrole) and Poly(3,4-propylenedioxypyrrole) Films with Hyperbranched Alkyl Chains.

Here, we control the surface hydrophobicity and the adhesion of water droplets by electrodeposition of poly(3,4-ethylenedioxypyrrole) (PEDOP) and poly(3,4-propylenedioxypyrrole) (PProDOP) with branched alkyl chains placed preferentially on the bridge to favor the formation of nanofibers. Branched alkyl chains of various sizes from very short (C3) to hyperbranched (C18) are studied because they have lower surface hydrophobicity than long alkyl or fluoroalkyl chains (preferable for parahydrophobic properties). The electrodeposition is much more favored with the PEDOP derivatives because the ProDOP films are more soluble. However, the formation of nanoparticles is favored with the PEDOP polymers in contrast to the formation of fibers, resembling the wax nanoclusters observed on lotus leaves, with the ProDOP polymers. With both these PEDOP and PProDOP derivatives, it is possible to reach parahydrophobic properties characterized by a sticking behavior toward water droplets. This kind of surfaces could be used in the future in water harvesting systems, for example.