Supramolecular metal-phenolic thin films attract an increasing interest since they allow the design of new types of self-assembling materials, such as tunable electronics or biomaterials. In this study, a new electrotriggered self-assembly of tannic acid-Fe(III) (TA-Fe(III)) nanocoatings was developed using the morphogenic approach with Fe(III) ions as a morphogen. Morphogens are molecules or ions produced locally that diffuse into the solution and induce a chemical reaction or interaction in a confined space near a surface. Using a mixture of TA and Fe(II) ions in contact with an electrode, a confined electrogenerated gradient of Fe(III) was obtained by application of an anodic current to locally form TA-Fe(III) coordination complexes. TA-Fe(III) nanocoatings, based on di-and tri-coordinated complexes, were thus obtained. Both the film thickness and its self-assembly kinetic were tuned by controlling Fe(II)/TA molar ratio of the building solution, the intensity and the duration of the applied current. We showed that this strategy can be applied to two other polyphenols (gallic acid and rosmarinic acid). This new electrotriggered confined self-assembly of metalpolyphenol gives new perspectives in application such as anti-oxidant coating.

From a selective enrichment culture prepared with different soil samples on starch-containing polyethylene we isolated four microaerophilic microbial communities able to grow on this kind of plastic with no additional carbon source. One consortium, designated community 3S, was tested with pure isotactic polypropylene to determine whether the consortium was able to degrade this polymer. Polypropylene strips were incubated for 5 months in a mineral medium containing sodium lactate and glucose in screw-cap bottles. Dichloromethane crude extracts of the cultures revealed that the weight of extracted materials increased with incubation time, while the polypropylene sample weight decreased. The extracted materials were characterized by performing chromatographic and spectral analyses (thin-layer chromatography, liquid chromatography, gas chromatography-mass spectrometry, infrared spectrometry, nuclear magnetic resonance). Three main fractions were detected and analyzed; a mixture of hydrocarbons at different degrees of functionalization was found together with a mixture of aromatic esters, as the plasticizers usually added to polyolefinic structures.