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

Abstract

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 (O 2 and/or H 2 ) 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)’.

A bioinspired strategy for designing well-ordered nanotubular structures by templateless electropolymerization of thieno[3,4- b ]thiophene-based monomers

“…With this strategy, the base structure of the polymerizing monomer is much more critical, as the monomer and polymer directly stabilize gas bubbles formed in solution. Owing to their rigidity and π-stacking interactions, monomers based on 3,4-phenylenedioxythiophene (PheDOT), 3,4-naphtalenedioxythiophene (NaphDOT) and thienothiophene are excellent candidates to develop nanoporous structures from electropolymerization in organic solvents, and this has been demonstrated for CH 2 Cl 2 as solvent [30][31][32][33][34][35][36]. Within this subset of potential monomers for in situ electropolymerization, thieno [3,4b]thiophene derivatives are particularly interesting as they have exceptional opto-electronic properties.…”

Templateless Electrodeposition of Conducting Polymer Nanotubes on Mesh Substrates

“…[21][22][23][24][25] Very recently, by a judicious choice in monomer and H 2 O content, the templateless electropolymerization process in organic solvent such as dichloromethane (CH 2 Cl 2 ) has been proposed as an efficient method to prepare extremely well-controlled porous nanostructures such as vertically aligned nanotubes. [26][27][28][29][30][31][32][33] Trace H 2 O naturally present in solution are responsible for the formation of gas bubbles (O 2 and/or H 2 ). The method does not require any acid or surfactant but the monomer has to play the role of the surfactant in stabilizing gas bubbles during electropolymerization.…”

“…In the first one, substituted monomers of the thieno [3,4-b]thiophene family are selected for their capacity to form nanotubular structures. [30][31][32][33] Three substituents of different hydrophobicity are chosen: pyrene, perfluorobutyl (C 4 F 9 ), and perfluorooctyl (C 8 F 17 ) chains. In the second strategy, a thieno [3,4- [29,31] for example, by adding different amount of H 2 O and it was shown that the increase in H 2 O can often increase the number of nanotubes or other porous structures.…”

“…In the first one, substituted monomers of the thieno[3,4‐ b ]thiophene family are selected for their capacity to form nanotubular structures. [ 30–33 ] Three substituents of different hydrophobicity are chosen: pyrene, perfluorobutyl (C 4 F 9 ), and perfluorooctyl (C 8 F 17 ) chains. In the second strategy, a thieno[3,4‐ b ]thiophene monomer with a functional hydroxyl group (OH) is first electropolymerized before to graft perfluorinated chains by simple esterification reaction.…”

Tuning nanotubular structures by templateless electropolymerization with thieno[3,4-b]thiophene-based monomers with different substituents and water content

“…Unfortunately, electropolymerization in H2O often requires high monomer concentration and most of the monomers employed have limited solubility in H2O. Fortunately, the possibility to use organic solvent such as dichloromethane (CH2Cl2) with trace H2O present in solution was recently reported [36][37][38][39][40][41][42]. By designing monomers that can also play the role of the surfactant, it is possible to obtain homogeneous porous structures without a separate surfactant.…”