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DOI: 10.1051/refdp/20154445086
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This invention relates to agricultural adjuvant compositions,pesticide compositions and methods for using such compositions, and in particular to adjuvant compositions useful in providing anti-drift properties.

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DOI: 10.1038/srep18002
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The development of visible-light responsive photocatalysts would permit more efficient use ofsolar energy, and thus would bring sustainable solutions to many environmental issues. Conductivepolymers appear as a new class of very active photocatalysts under visible light. Among them poly(3,4-ethylenedioxythiophene) (PEDOT) is one of the most promising conjugated polymer with a widerange of applications. PEDOT nanostructures synthesized in soft templates via chemical oxidativepolymerization demonstrate unprecedented photocatalytic activities for water treatment withoutthe assistance of sacrificial reagents or noble metal co-catalysts and turn out to be better than TiO2as benchmark catalyst. The PEDOT nanostructures exhibit a narrow band gap (E = 1.69 eV) and arecharacterized by excellent ability to absorb light in visible and near infrared region. The novel PEDOTbasedphotocatalysts are very stable with cycling and can be reused without appreciable loss of activity.Interestingly, hollow micrometric vesicular structures of PEDOT are not effective photocatalysts ascompared to nanometric spindles suggesting size and shape dependent photocatalytic properties.The visible-light active photocatalytic properties of the polymer nanostructures present promisingapplications in solar light harvesting and broader fields.

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Ref Arxiv: 1511.00451
DOI: 10.1103/PhysRevLett.115.198302
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We study the destabilization mechanism of thin liquid sheets expanding in air and show that dilute oil-in-water emulsion-based sheets disintegrate through the nucleation and growth of holes that perforate the sheet. The velocity and thickness fields of the sheet outside the holes are not perturbed by holes and hole opening follows a Taylor-Culick law. We find that a pre-hole, which widens and thins out the sheet with time, systematically precedes the hole nucleation. The growth dynamics of the pre-hole follows the law theoretically predicted for a liquid spreading on another liquid of higher surface tension due to Marangoni stresses. Classical Marangoni spreading experiments quantitatively corroborate our findings.

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DOI: 10.1039/c5nj00826c
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Oil-swollen hexagonal mesophases resulting from the surfactant mediated self-assembly of a quaternarymixture of water, surfactant, co-surfactant, and oil, are versatile templates to synthesize anisotropicnanomaterials. Poly(diphenylbutadyine) (PDPB) polymer nanofibrous network structures were producedin the oil tubes of the mesophases by photo-induced radical polymerization using a chemical initiator orby gamma irradiation. The diameter of the nanofibers can be varied from 5 to 25 nm in a controlledfashion, and is directly determined by the diameter of the oil tube of the doped mesophases, proving thusa direct templating effect of the mesophase. The nanoIR technique allows chemical characterization andidentification of the polymer nanostructures simultaneously with morphological characterization. Cyclicvoltammetry has been used as an effective approach to evaluate both the energy level of the highestoccupied molecular orbital (HOMO) as well as the energy of the lowest unoccupied molecular orbital(LUMO) and the band gap of the PDPB. The conductivity of the PDPB nanostructures obtained by gammairradiation was estimated to be 0.1 S/cm, which is higher than the conductivity of PDPB nanostructurespreviously reported in the literature. The soft template approach allows size tunable synthesis of anisotropicpolymer structures with morphological homogeneity at the nanoscale with high conductivity, thus it appearsto be an attractive opportunity for electronic device applications.

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Agricultural spraying involves atomizing a liquid stream through a hydraulic nozzle forming a liquid sheet, which is subsequently destabilized into drops. Standard solution adjuvants as dilute oil-in-water emulsions are known to influence the spray drop size distribution. We will present model laboratory experiments that aim to elucidate the physical mechanisms causing the changes of drop size distribution. Model laboratory experiments based on the collision of a liquid drop on a small solid target are used to produce and visualize liquid sheets. With dilute oil-in-water emulsions, the liquid sheet is destabilized by the nucleation and growth of holes within the sheet that perforate it during its expansion. The physical-chemical parameters of the emulsion, such as the emulsion concentration, the chemical nature of the components and the emulsion drop size distribution, are varied to rationalize their influence on the perforation mechanisms. Thanks to an original technique that we recently developed to access the time and space-resolved thickness of the sheet, we measure that the formation of a hole within the sheet is preceded by a localized thinning of the liquid film. We show that this thinning results from the entry and spreading of emulsion oil droplets at the air/water interface. The oil droplet spreading, due to Marangoni driven surface tension gradient, drags subsurface fluid with it. This subsurface flow causes a local film thinning which can ultimately rupture the film. Quantitative analysis of the spreading dynamics unambiguous confirms the physical mechanism at the origin of our observations.

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Ref Arxiv: 1509.07987
DOI: 10.1103/PhysRevE.92.032307
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We investigate how the microstructure of a colloidal polycrystal influences its linear viscoelasticity. We use thermosensitive copolymer micelles that arrange in water in a cubic crystalline lattice, yielding a colloidal polycrystal. The polycrystal is doped with a small amount of nanoparticles, of size comparable to that of the micelles, which behave as impurities and thus partially segregate in the grain boundaries. We show that the shear elastic modulus only depends on the packing of the micelles and does not vary neither with the presence of nanoparticles nor with the crystal microstructure. By contrast, we find that the loss modulus is strongly affected by the presence of nanoparticles. A comparison between rheology data and small-angle neutron scattering data suggests that the loss modulus is dictated by the total amount of nanoparticles in the grain boundaries, which in turn depends on the sample microstructure.

Commentaires: . Réf Journal: Physical Review E, 92, 032307, 2015