[en] Life cycle analysis (LCA) of limonene plasticized poly(lactic acid) (PLA) films containing cellulose nanocrystals (CNC) extracted, by acid hydrolysis, from Phormium tenax leaf fibres, was assessed and compared with the results of acetyl tributyl citrate (ATBC) plasticized PLA films, having equivalent mechanical properties, containing organo-modified montmorillonite (OMMT). Eco-Indicator 99 tool has been adopted as the main method for life cycle assessment. Results indicated that, despite CNC are biobased fillers obtained by natural sources, the related chemical extraction leads to a large environmental footprint and a relatively relevant energy expense. LCA characterization of these films demonstrated that the environmental impact of PLA/limonene film reinforced with 1% in weight of CNC (PLA/CNC/limonene) is comparable to the environmental impact of polylactic acid films reinforced with OMMT and plasticized with a petroleum based plasticizer (ATBC) (PLA/OMTT/ATBC). A “cradle to gate” approach has been considered for both the film typologies.

[en] A deposition process on a conducting surface, in which water acted as the dispersed phase and a mixture of poly(methyl methacrylate) and chloroform as the continuous phase, was applied to prepare poly(methyl methacrylate) films. The influence of relative humidity during the film preparation on the surface morphology was investigated by field emission scanning microscopy. High-humidity preparation conditions lead to porous poly(methyl methacrylate) films. These films were then used as templates to perform the selective deposition into the pores of single-walled carbon nanotubes by an electrophoretic method. The attractive properties of carbon nanotubes combined with the versatile properties of poly(methyl methacrylate) open up new opportunities for these nanocomposites to achieve novel architectures in nanodevices and microdevices

[en] In this paper the dip-coating technique has been investigated as a method for the production of regioregular poly(3-hexylthiophene) (RR-P3HT):[6,6]-phenyl C₆₁-butyric acid methyl ester (PCBM)-based solar cells. We found that the utilization of the dip-coating technique for the RR-P3HT:PCBM system can facilitate its self-assembly into a nanofibrillar lamellar structure after evaporation of the solvent. The condition for the formation of the nanofibrillar structures leads to a power conversion efficiency of 3.6% by using only this approach without thermal treatment.

[en] Different types of fluorinated amorphous carbon (a-C:H:F) thin films were grown by CH₄/CF₄/Ar mixtures using a 13.56 MHz radio frequency (rf) and a 13.56 MHz rf -2.45 GHz microwave hybrid plasma source. The optical properties of films were carried out by ellipsometric measurement, while x-ray photoelectron spectroscopy (XPS) and Raman spectroscopy were exploited to study their structural and vibrational properties. XPS spectra showed that the fluorine incorporation increased with the CF₄ partial pressure while fluorine-poorer films were deposited with the rf-microwave hybrid technique. Raman measurements also suggested that with increasing fluorine content, the film microstructure changed from diamond-like to polymer-like. The mechanism of the a-C:H:F refractive index dependency on the plasma source frequency is investigated in terms of the amount of fluorine incorporation in the films produced

[en] This paper reviews research into the electrical properties that are imparted to composite materials by introducing carbon nanotubes (CNTs) into their polymer matrices. Due to the large aspect ratio of CNTs, even a small amount of doping (at a level of 0.01 - 0.1%) is enough to increase the conductivity of the material by more than ten orders of magnitude, thus changing it from an insulator to a conductor. At low doping, charge transfer is of a percolation nature in the sense that nanotubes that are in contact with each other form conducting channels in the material. Importantly, the conductivity has a threshold nature, so that the conduction jump occurs upon an arbitrarily small increase in a doping level above the critical value. This paper summarizes experimental data on the position of the percolation threshold and the maximum magnitude of the conductivity for composites obtained using various polymer types and a variety of CNT geometries. Factors affecting the electrical characteristics of composites produced by distinct methods are analyzed. Methods for and basic results obtained from the simulation of the percolation conductivity of CNT-doped composites are discussed. Particular attention is given to contact phenomena that occur at adjacent nanotube boundaries and which determine the conductivity of CNT-doped composites. (reviews of topical problems)

[en] With the continuous advance of modern electronics, the demand for nonvolatile memory cells rapidly grows. In order to develop post-silicon electronic devices, it is necessary to find innovative solutions to the eco-sustainability problem of materials for nonvolatile memory cells. In this work, we realized a resistive memory device based on graphene oxide (GO) and GO/cellulose nanocrystals (CNC) thin films. Aqueous solutions of GO and GO with CNC have been prepared and drop cast between two metal electrodes. Such thin-film based devices showed a transition between low and high conductivity states upon the forward and backward sweeping of an external electric field. This reversible current density transition behavior demonstrates a typical memory characteristic. The obtained results open an easy route for electronic information storage based on the integration of nanocrystalline cellulose onto graphene based devices.

[en] Electrophoretically deposited single-walled carbon nanotube (SWCNT) films on a transparent conducting surface are used as electrodes for the electrodeposition of a π-conjugated polymer formed by the oxidative coupling of fluorene units. This method provides a uniform coverage of the conducting surface with respect to SWCNTs chemically assembled on a gold substrate. Electron microscopy reveals the formation of a polymer-SWCNT nanostructure which imparts distinct electrical properties from those of the polymer electrodeposited on the neat electrode. By combining the attractive properties of SWCNTs and polyfluorene, these nanocomposites open up new opportunities to achieve electrical contacts in nano- to micro-devices

[en] We study the dependence of the dynamics on the size of particle clusters that grow by stepwise aggregation in a two-component reactive mixture. The data reveal the cluster property involved in the glasslike arrest and its quantitative link with the structural relaxation time. Specifically, we measured the number-average cluster size x_n-i.e., the average number of bonded monomers per molecule-and, independently, the characteristic time τ for decay of the photon correlation function, throughout the reaction. We find that x_n diverges as the system freezes at the glass transition, x_n and τ being exponentially related. The comparison with the gel transition that occurs at the divergence of the weight-average cluster size provides evidence that the two transitions are associated to distinct properties of the same underlying clustering process