Poly(3-n-butylthiophene) (P3BT) samples with different average molecular weights and headto-tail regioregularity were crystallized in the form II crystal polymorph either from solution or by annealing with CS 2 vapors. With a combined approach, making also use of literature electron diffraction data, we show that form II is well described by a limit-ordered monoclinic model in space group P2 1 /c with lattice parameters a = 10.76(1) A ˚, b = 7.77(1) A ˚(chain axis), c = 9.44(1) A ˚, and β = 64.66°, yielding a calculated density of 1.29 g/cm 3 in qualitative agreement with proposals by Winokur et al. for the form II structures of regioregular poly(3-octylthiophene) and poly(3-dodecylthiophene) (P3DDT). Our structural model was refined by Rietveld analysis and has been confirmed by molecular mechanics (MM) and molecular dynamics (MD) calculations adopting a thiophene-specific force field developed in our group. Consistent with its higher density and with thermal data, form II shows lower potential energy than the form I 0 crystalline polymorph of P3BT. Both the main-chain and the side-chain conformations closely correspond to those found in form I 0 polymorph. The form II P3BT refined structural model presents an antidirectional looser stacking and tightly interdigitated layering, different from those observed in the form I family of poly(3-alkythiophenes) (P3ATs) and crystallite dimension of 20-30 A ˚along the chain axis. This feature and the lamellar structure implied by the spherulitic morphology are consistent with substantial chain-folding for high molecular weight samples. Oriented X-ray diffraction patterns from thin films of form II P3BT are explained assuming that the stacking axis c, corresponding to the radial, fast growth direction of the bidimensional form II spherulites, is preferentially in the plane of the film, while the layer axis a and the chain axis b approach random orientation around c, at variance with recent literature suggestions. The small crystal dimensions along the chain axis, the looser stacking, the relevance of chain folding and the spherulitic morphology implying film discontinuity suggest that the form II structural family of P3AT's are less viable than the form I polymorphs for molecular electronics applications.

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Polyethylene (PE) and polypropylene (PP) were oxygen plasma treated and aged in carefully reproducible conditions. The effect of aging on the surface chemistry, wettability and adhesion were studied using a combination of techniques: contact angle measurements, XPS, SSIMS, adhesion tests (shear and pull).PE was found to be relatively insensitive to aging both in terms of wettability and adhesion, due to crosslinking during plasma treatment, which is likely to reduce macromolecular mobility within the surface layer.In the case. of PP, dramatic decreases of wettability occur with time, due to macromolecular motions leading to minimization of oxygen-containing functions at the surface. This behavior was shown to affect the adhesion performance of treated PP.

To achieve rationalization criteria for target-oriented molecular design of Th-X-Th (Th = thiophene) semiconductor building blocks, we have carried out an extensive investigation on the effects of the X core (X = fluorene, carbazole or phenothiazine) on the electronic properties and polymerization ability of Th-X-Th monomers and on the electronic and structural properties of the corresponding periodic conducting polymers -(Th-X-Th) n -, obtained by electropolymerization and, for

The latest developments in photovoltaic studies focus on the best use of the solar spectrum through Luminescent Solar Concentrators (LSC). Due to their structural characteristics, LSC panels allow considerable energy savings. This significant saving can also be of great interest in the remediation of contaminated sites, which nowadays requires green interventions characterized by high environmental sustainability. This study reported the evaluation of LSC panels in phytoremediation feasibility tests. Three plant species were used at a microcosm scale on soil contaminated by arsenic and lead. The experiments were conducted by comparing plants grown under LSC panels doped with Lumogen Red F305 (BASF) with plants grown under polycarbonate panels used for greenhouse construction. The results showed a higher production of biomass by the plants grown under the LSC panels. The uptake of the two contaminants by plants was the same in both the growing conditions, thus resulting in an increased total accumulation (defined as metal concentration times produced biomass) in plants grown under LSC panels, indicating an overall higher phytoextraction efficiency. This seems to confirm the potential that LSCs have to be building-integrated on greenhouse roofs, canopies, and shelters to produce electricity while increasing plants productivity, thus reducing environmental pollution, and increasing sustainability.