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Abstract: Process of formation of polyaniline (PANI) at the surface of SiC and CdS nanoparticles or submicron- and micron-sized particles of poly(vinylidene fluoride) (PVDF), polycarbonate and polyamides-11, 12 and properties of the prepared composites are considered. Beginning of the formation of the PANI shell at the particle surface was evaluated. This important result opens the possibility to control properties of the final hybrid composite. In case of CdS nanoparticles PANI was synthesized in the form of nanofibers embedding these nanoparticles. Films of the PANI–polymer composites showed the conductivity of up to ∼0.4S/cm. The planar heterojunction of the compression molded PVDF/PANI–DBSA film with bulk CdS displayed photovoltaic activity. [Copyright &y& Elsevier]

Abstract: Thin (1–40μm) films of nanostructured polyaniline (PANI)-based composites are suggested for ppb range ammonia sensing. Three types of the composites have been studied: two core–shell systems with a poly(butyl acrylate) (PBuA) or poly(vinylidene fluoride) (PVDF) core and a PANI shell, and a composite based on PANI nanofibers embedded in a polyurethane (PU) matrix. Nanofibers and core–shell nanoparticles had a diameter around 100–200nm. The gas sensing ability of the nanostructured films was compared to ammonia concentrations from 20ppb to 10ppm through the change of the sensors resistance. All the composites showed high performances in terms of response time, reversibility and detection limit. Specifically, the last parameter was below 100ppb for films formed of the core–shell nanoparticles and below 20ppb for the nanofiber based composites. However, while the response times were similar for all of the samples, the films made of the contacting core–shell nanoparticles had a higher sensitivity than PANI nanofibers embedded in the PU film matrix. The obtained results showed that nanostructured PANI-based composites of different morphologies can be used as ultra-sensitive and low cost ammonia gas sensors. [Copyright &y& Elsevier]

Abstract: The structure and electrical properties of polyaniline (PANI) modified poly(vinylidene fluoride) (PVDF) films have been studied depending on the type of modification (surface or volume) and the type of dopant (HCl or dodecylbenzenesulfonic acid). The structure was studied with differential scanning calorimetry, atomic force microscopy and Raman spectroscopy (including the surface enhanced mode—SERS) techniques. Surface modification of PVDF with PANI creates a two-dimensional (2D) conductive network on the surface of PVDF films with the thickness of approximately 8μm. The network is characterized with non-linear current voltage (I–V) characteristics and enhanced conductivity at elevated temperatures (up to 160°C), which is opposite to volume modified samples behaviour. Conductivity of the composite films varies in the range of 10−8 to 10−3 S/cm depending on the preparation conditions. The observed non-linear conductivity is explained by formation of the surface conductive network of PANI alternated with β-crystalline PVDF microdomains. [Copyright &y& Elsevier]