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Only recently polymers with intrinsic conductive properties have been studied in relation to their incorporation into bioactive scaffolds for use in tissue engineering. The reason for this interest is that such scaffolds could electrically stimulate cells and thus regulate specific cellular activities, and by this means influence the process of regeneration of those tissues that respond to electrical impulses. In our work, macroporous hydrogels are developed with controlled pore morphology and conductive properties to enable sufficient cell signaling to supply events inherent to nerve regeneration. A hybrid material has been prepared by in situ precipitation of polyaniline (PANi) in polyethyleneglycol diacrylate (PEGDA) solution, followed by crosslinking via UV irradiation. A porous architecture, characterized by macropores from 136 μm to 158 μm in size, has been achieved by sodium chloride particle leaching. In this work, we demonstrate that PANi synthesis and hydrogel crosslinking combine to enable the design of materials with suitable conductive behaviour. The presence of PANi evidently increased the electrical conductivity of the hybrid material from (1.1 ± 0.5) × 10(-3) mS/cm with a PANi content of 3wt%. The hydrophilic nature of PANi also enhanced water retention/proton conductivity by more than one order of magnitude. In vitro studies confirmed that 3 wt% PANi also improve the biological response of PC12 and hMSC cells. Hybrid PANi/PEGDA macroporous hydrogels supplement new functionalities in terms of morphological and conductive properties, both of which are essential prerequisites to drive nerve cells in regenerative processes.

Proton conductivity of innovative ionomeric membranes based on partially sulfonated syndiotactic polystyrene (SsPS) was investigated. The membranes were prepared with various levels of sulfonation by chlorosulfonic reaction on sPS films, in its clathrate form, obtained by solution-casting. The actual sulfonation degree of sPS membranes was evaluated by elemental analysis and their proton conductivity was measured using a galvanostatic four-points-probe electrochemical impedance spectroscopy technique. The dependence of conductivity on the level of sulfonation, hydration condition, and temperature was studied. At higher sulfonation degrees, SsPS membranes showed the best performance in vapor phase at 100% RH. In particular, the best SsPS membrane with sulfonation degree about 26 mol% exhibited conductivity equal to 8.8 × 10−2 Ω−1 cm−1 at 31.5 °C. This property is stable during time and increases with temperature. For the membranes with the highest degree of sulfonation, we measured a methanol permeability ...

Today’s lithographic techniques for carving silicon into circuit patterns are unable to achieve the future target of the semiconductor industry of fabricating ultrahigh density memory devices made of memory cells just few tens of nanometers apart. Methods of extending these approaches to large-scale, high-density circuitry are largely undeveloped. Between emerging self-assembly bottom-up methods for advanced fabrication of electronic devices based on organic matrices, nanocomposites formed by a conducting phase (e.g. metal nanoparticles) dispersed in a polymeric matrix have attracted considerable attention, because these materials might be used as an active layer in almost all kinds of organic electronic devices. In this paper a different approach for the fabrication of advanced electronic devices is suggested, based on the combination of two concepts: the use of organic materials as active layers that guarantees simplified manufacturing process yielding low-cost, flexible, and light-weight devices, and the use of self-assembly of block copolymers (BCPs) that allows building nanostructures from the bottom up using individual macromolecules. The ordered cylindrical self-assembled nanostructure formed from PS- b -PMMA is used as host for selectively sequestering gold nanoparticles. The ordered distribution of the functional particles is guided by the ordering of the host matrix and allows arising other numerous possible applications that depend on the nanospecific properties of the sequestered components and the intrinsic flexibility of the polymeric matrix. The BCP structure has many considerable advantages in terms of low material consumptions and reduced operating voltages for producing high bistability effects in well ordered nanostructures. Moreover, the excellent results we achieved in terms of electronic performances and the high potential opened by this nanotechnology toward the development of innovative materials open the way toward the realization of novel organic devices containing different physical types of functionalized nanoparticles (e.g. oxides, superconductors, etc.), and the investigation of their fundamental properties.

A helical crystalline modification of syndiotactic polystyrene (sPS), the δ-form, was employed to prepare solution-cast films selectively sulfonated on the surface. This result was achieved because of the unusual transport characteristics of the δ-form, exhibiting comparatively large diffusivity and solubility values for low-molecular weight compounds such as chloroform, which can be effectively used as a carrier solvent. The results of sulfonation of the δ-form are compared with those obtained with a trans-planar crystalline modification of sPS (β-form). The latter was found unsuitable for selective surface modification. The analysis of the sulfonated films was carried out by FT-Raman and confocal-Raman spectroscopy. The first technique was used to investigate the average composition of the samples in terms of sulfonation degree and crystalline structure. It also allowed us to construct calibration curves to be used in connection with the confocal-Raman data. The latter technique was employed to generate images with spectroscopic contrast and to quantitatively characterize the depth-profiles of the investigated films.