The effect of annealing temperature and time on the dielectric and piezoelectric response of poly(vinylidene fluoride), PVDF, has been studied. The observed decrease in the value of the dielectric, ´, and piezoelectric, d 33 , constants is related to depoling of the material and not to variations of the degree of crystallinity or the electroactive -phase content. In a general way, the dielectric and piezoelectric responses decrease strongly in the first four hours at a given temperature, in particular for temperatures higher that 80 ºC, reaching stable values for longer annealing times. For most applications, the temperature of 100 ºC will set the limit of suitable performance. Nevertheless, the material still retains stable piezoelectric response of ~ 4 pC/N after reaching temperatures of

The piezoresistive effect on poly(propylene) (PP)-carbon nanofibre (CNF) composites fabricated by twin-screw extrusion and compression moulding has been investigated. The electrical and mechanical properties of PP/CNF composites have been obtained as a function of CNF concentration. Electrical conductivity exhibited low thresholds and values close to the required levels for EMI shielding applications at 2.4 vol%. Meanwhile the elastic modulus showed an enhancement with a maximum up to 130% for one of the composites at 0.9 vol% loading. Further, the piezoresistive response has been evaluated in four-point bending. Positive gauge factors between 2 and 2.5 have been obtained. The highest gauge factors are found within the percolation threshold. The characteristics of the materials and the production technique make them suitable for large scale applications.

A cost-competitive, flexible and safe thermoelectric polyamide 6,6 (PA66) fabric coated with glycerol-doped PEDOT:PSS (PEDOT:PSS + GLY) for use in large area textiles as a heating element in several applications.

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In this work, epoxy composites reinforced with vapor‐grown carbon nanofibers were prepared by a simple dispersion method and studied in order to identify the main conduction mechanism. The samples show high electrical conductivity values. The results indicate that a good cluster distribution seems to be more important than the fillers dispersion in order to achieve high conductivity values. Interparticle tunneling has been identified as the main mechanism responsible for the observed behavior.

Polymeric materials have been replacing other materials in various applications, from structural to electronic components. In particular, since the discovery of conducting polymers, the use of these materials is growing up in the manufacture of electronic components, such as organic lightemitting diodes, organic electrodes, energy storage devices and artificial muscles, among others. On the other hand, examples of sensors of conductive polymers based on the piezoresistive effect, with large potential for applications, are not sufficiently investigated. This work reports on the piezoresistive effect of an intrinsically conductive polymer, polyaniline, which was prepared in the form of thin films by spin coating on polyethylene terephthalate substrates. The relationship between electrical response and mechanical solicitations is presented for different preparation conditions. The values of the gauge factor ranges from 10 to 22 for different samples and demonstrates the viability of these materials as piezoresistive sensors.

Cotton woven fabrics functionalized with aqueous inks made with carbon nanofibers (CNFs) and anionic surfactant are prepared via dip-coating followed by heat treatment, and their electronic properties are discussed. The e-textiles prepared with the inks made with the highest amount of CNFs (6.4 mg mL −1 ) show electrical conductivities (σ) of ∼35 S m −1 and a negative Seebeck (S) of −6 μV K −1 at 30 °C, which means that their majority carriers are electrons. The σ(T) of the e-textiles from 30 to 100 °C shows a negative temperature effect, interpreted as a thermally activated hopping mechanism across a random network of potential wells by means of the 3D variable range hopping (VRH) model. Likewise, their S(T) from 30 to 100 °C shows a negative temperature effect, conveniently depicted by the same model proposed for describing the negative Seebeck of doped multiwall carbon nanotube mats. From this model, it is deduced that the cause of the negative Seebeck in the e-textiles may arise from the contribution of the impurities found in the as-received CNFs, which cause sharply varying and localized states at approximately 0.085 eV above their Fermi energy level (E F ). Moreover, the possibility of a slight n-doping from the cellulose fibers of the fabrics and the residuals of the anionic surfactant onto the most external CNF graphitic shells present in the e-textiles is also discussed with the help of the σ(T) and S(T) analysis.

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