A lighting system embedded in a mortar structure powered by an inductive system is described. Different additives with high magnetic permeability were tested to increase power transference efficiency. The best results were obtained using natural magnetite, therefore the impact of different natural magnetite concentrations on the mortar mechanical and electromagnetic properties was investigated. The best results were achieved for samples with 75 wt.% of magnetite. With this composition, three proofs‐of‐concept were fabricated to show the potential of the technology.

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Soft robotics is an expanding area with multiple applications; however, building low-cost, soft, and flexible robots requires the development of sensors that can be directly integrated into the soft robotics fabrication process. Thus, the motivation for this work was the design of a low-cost fabrication process of flexible sensors that can detect touch and deformation. The fabrication process proposed uses a flexible polymer nanocomposite with permanent magnets strategically placed where the conductive electrodes should be. The nanocomposite is based on poly(dimethylsiloxane) (PDMS) and multi-walled carbon nanotubes (MWCNTs). The MWCNT contains ferromagnetic impurities remaining from the synthesis process, which can be used for magnetic manipulation. Several electrode geometries were successfully simulated and tested. The magnetic patterning was simulated, allowing the fabrication of conductive patterns within the composite. This fabrication process allowed the reduction of the electrical resistivity of the nanocomposites as compared to the composites with homogeneous MWCNT dispersion. It also allowed the fabrication of piezoresistive and triboelectric sensors at MWCNT concentration as low as 0.5 wt.%. The fabrication process proposed is flexible, allows the development of sensors for soft robotics, as well as monitoring large and unconventional areas, and may be adapted to different mould shapes and polymers at low cost.

The fabrication of low-electrical-percolation-threshold polymer composites aims to reduce the weight fraction of the conductive nanomaterial necessary to achieve a given level of electrical resistivity of the composite. The present work aimed at preparing composites based on multiwalled carbon nanotubes (MWCNTs) and magnetite particles in a polyurethane (PU) matrix to study the effect on the electrical resistance of electrodes produced under magnetic fields. Composites with 1 wt.% of MWCNT, 1 wt.% of magnetite and combinations of both were prepared and analysed. The hybrid composites combined MWCNTs and magnetite at the weight ratios of 1:1; 1:1/6; 1:1/12; and 1:1/24. The results showed that MWCNTs were responsible for the electrical conductivity of the composites since the composites with 1 wt.% magnetite were non-conductive. Combining magnetite particles with MWCNTs reduces the electrical resistance of the composite. SQUID analysis showed that MWCNTs simultaneously exhibit ferromagnetism and diamagnetism, ferromagnetism being dominant at lower magnetic fields and diamagnetism being dominant at higher fields. Conversely, magnetite particles present a ferromagnetic response much stronger than MWCNTs. Finally, optical microscopy (OM) and X-ray micro computed tomography (micro CT) identified the interaction between particles and their location inside the composite. In conclusion, the combination of magnetite and MWCNTs in a polymer composite allows for the control of the location of these particles using an external magnetic field, decreasing the electrical resistance of the electrodes produced. By adding 1 wt.% of magnetite to 1 wt.% of MWCNT (1:1), the electric resistance of the composites decreased from 9 × 104 to 5 × 103 Ω. This approach significantly improved the reproducibility of the electrode’s fabrication process, enabling the development of a triboelectric sensor using a polyurethane (PU) composite and silicone rubber (SR). Finally, the method’s bearing was demonstrated by developing an automated robotic soft grip with tendon-driven actuation controlled by the triboelectric sensor. The results indicate that magnetic patterning is a versatile and low-cost approach to manufacturing sensors for soft robotics.