The crystallization and melting behavior of poly(3-butylthiophene) (P3BT), poly(3-octylthiophene) (P3OT), and poly(3-dodecylthiophene) (P3DDT) were studied. The equilibrium melting temperatures (T m 0) of these polymers were measured and resulted equal to 321, 230, and 175 °C for P3BT, P3OT, and P3DDT, respectively. The crystallization kinetics was evaluated by the Avrami equation:  it proceeds by heterogeneous nucleation with one-dimensional linear growth (n = 1.1−1.8). The effects of the length of the alkyl side chain and of the undercooling were investigated. Phase I, Phase II, and a nematic mesophase were detected in P3BT and P3DDT. In P3BT, Phase I was differentiable from the mesophase on the basis of wide-angle X-ray scattering (WAXS) patterns. This study gives insight, in particular, on the crystallization and melting behavior of P3BT, a polymer not yet well studied. WAXS, small-angle X-ray scattering (SAXS), and differential scanning calorimetry (DSC) were employed as experimental techniques.

Cyclic poly-2-ethyl-2-oxazoline (PEOXA) ligands for superparamagnetic Fe O nanoparticles (NPs) generate ultra-dense and highly compact shells, providing enhanced colloidal stability and bio-inertness in physiological media. When linear brush shells fail in providing colloidal stabilization to NPs, the cyclic ones assure long lasting dispersions. While the thermally induced dehydration of linear PEOXA shells cause irreversible aggregation of the NPs, the collapse and subsequent rehydration of similarly grafted cyclic brushes allow the full recovery of individually dispersed NPs. Although linear ligands are densely grafted onto Fe O cores, a small plasma protein such as bovine serum albumin (BSA) still physisorbs within their shells. In contrast, the impenetrable entropic shield provided by cyclic brushes efficiently prevents nonspecific interaction with proteins.

We report on the synthesis and characterisation of novel ionic liquid crystals and ionic liquids based on asymmetric viologen salts of bis(trifluoromethanesulfonyl)amide (Tf2N−). The thermotropic behaviour of the salts has been thoroughly characterized by DSC, X-ray diffraction and polarized light optical microscopy. The occurrence of smectic mesophases and the temperature range over which they are stable has been discussed as a result of the asymmetry of the viologen dications. Strongly asymmetric systems, not showing mesomorphism, have a rather low melting point (just beyond 40 °C) while slightly asymmetric samples exhibit a smectic phase with a wide range of stability, from about 0 °C up to above 140 °C, thus increasing the range of stability of the mesophase observed for the symmetric compounds. Finally, we report on the lyotropic behaviour in non-polar solvents, such as benzene, where liquid clathrates have been found

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In this paper, we report a comprehensive investigation of Pt nanoparticles (NPs) deposition on nitrogenand sulfur-doped or codoped mesoporous carbons (N-MC, S-MC, and N,S-MC) to develop active and durable oxygen reduction catalysts for fuel cells. N-MC, S-MC, and N,S-MC were prepared by employing mesoporous silica as hard template and suitable organic precursors. Pt NPs were deposited by solidstate reduction of platinum acetylacetonate under N 2 /H 2 flow on the three different supports. Pt NPs resulted to be welldispersed over the doped MC supports with size distributions (from 1.8 nm to 3.5 nm) that are dependent on the type of doping heteroatom (N, S, or N and S). The influence of nitrogen and/or sulfur incorporated into the carbon matrix on the nucleation and growth of Pt NPs was also rationalized based on density functional theory (DFT) simulations. They highlighted that both nitrogen and sulfur increase the interactions between Pt and carbon support, but the interaction decreases as the nitrogen and sulfur functional groups become closer. The effect of sulfur content on the size and activity of Pt NPs was also evaluated. Electrochemical measurements in 0.5 M H 2 SO 4 electrolyte allowed us to investigate the behavior of Pt NPs and to assess the relationship with electrochemical activity and stability. The Pt/S-MC showed mass activity and specific activity comparable with the state-of-the-art commercial standard Pt/C Tanaka (Pt 46% on Vulcan XC72), and the highest catalytic activity, with respect to Pt/N-MC and Pt/N,S-MC, was associated with a stronger interaction between Pt NPs and a thiophenic-like group, as proven by DFT calculations and X-ray photoelectron spectroscopy (XPS) analysis. Pt/S-MC was incorporated in a membrane electrode assembly and tested as cathode material in a PEM fuel cell, while accelerated degradation tests up to 10 000 voltammetric cycles were carried out in 0.5 M H 2 SO 4 : the influence of the doped support on the durability of the catalyst under harsh operational conditions has been highlighted.

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