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)’.
Inspired by natural species such as rose petals or Echeveria pulvinata leaves with both high water contact angle θw and high water adhesion (also called parahydrophobic), we have prepared poly(3,4‐propylenedioxypyrrole) with branched alkyl chains on the 3‐position by electropolymerization. The grafting at the 3‐position keeps the NH group free, which is an important condition to obtain nanofibers. Different lengths of branched alkyl chains are studied. Here, using extremely long branched alkyl chains (ProDOP‐br‐C10), it is possible to obtain extremely long and well defined nanofibers leading to porous surfaces (fiber mats) favoring the trapping of air between the surface and water droplets. Using a deposition charge of 200 mC cm−2, extremely high θw up to ≈ 140° while water droplets placed on this surface remained stuck even for a sliding angle of 90°, revealing extremely stron adhesion. These materials could be used in the future in water harvesting systems.
In the aim to obtain parahydrophobic
materials (both high contact angles and high hysteresis) for possible
applications in water harvesting systems, we report the synthesis
of novel 3,4-ethylenedioxypyrrole (EDOP) and 3,4-propylenedioxypyrrole
(ProDOP) monomers with aromatic rings on the 3,4-alkylenedioxy bridge
and the resulting conducting polymer films were prepared by electropolymerization.
We show that the surface properties can be tuned by the nature of
the aromatic ring (phenyl, biphenyl, diphenyl, naphthalene, fluorene,
and pyrene) and the polymerizable core (EDOP or ProDOP). The best
results are obtained with both EDOP and diphenyl, with which extremely
high hydrophobic properties (up to 116°) are obtained, even if
the polymers are intrinsically hydrophilic. These surfaces could be
applied in the future, for example, in water harvesting systems or
in water/oil separation membranes. The synthesis strategy is extremely
interesting, and many other molecules will be envisaged in the future.
Dans le cadre des Partenariats Public-Privé (PPP) des divergences naissent entre partenaires. Elles sont liées autant aux caractéristiques qu’aux objectifs opposés des acteurs du partenariat. Aussi est-il nécessaire de trouver des cadres pragmatiques et consensuels pour avancer dans la relation. Pourtant, prenant l’exemple de l’hydraulique urbaine et périurbaine au Sénégal, il a été noté de manière générale que les partenaires, malgré leur proximité géographique, n’ont pas pu dépasser leurs oppositions, du fait de logiques institutionnelles différentes, de la persistance de divergences d’objectifs. Rares ont été les moments de coopération.
Avec les Partenariats Public‐Privé (PPP), l’objectif est d’appliquer les techniques de gestion issues du secteur privé comme le préconisent les partisans du Nouveau Management Public (NMP). Pourtant, cette logique libérale, tendant à une remise en question de l’Administration Publique Wébérienne traditionnelle peut entrer en contradiction avec les exigences du service public puisque les usagers les plus démunis peuvent être confrontés aux prix pratiqués. Il est dès lors indispensable d’apprécier les mesures sociales que peuvent prendre les pouvoirs publics, acteurs dans le cadre de PPP, afin d’éviter que de tels usagers ne subissent la logique de rentabilisation financière souvent exigée par les partenaires privés. Le cas de PPP pris en exemple concerne l’exploitation de l’hydraulique urbaine et périurbaine au Sénégal et permet de comprendre qu’un consensus sur l’application de mesures sociales peut donner au PPP un visage plus humain, davantage en phase avec la vocation du service public, tout en permettant aux partenaires privés des organisations publiques d’assurer un retour sur investissement.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.