Recently, high performance flexible sensors are in great demand for improving the proprioceptive and exteroceptive capabilities of novel soft robots, for the health monitoring of complex structures such as morphing aircrafts and for the physiological-biomechanical monitoring with wearable devices. The project aims to develop a new sensing material for the real-time monitoring of small/large deformations and potentially interesting for those applications where lightness, relevant stretchability, compressibility and high sensitivity are required. In particular, the activity will be focused on the development of innovative piezoresistive sensors made of novel three-dimensional (3D) graphene nanoplatelets (MLG)/elastomer-based ordered open-cell foams, surpassing the limits of current graphene-based foams with disordered morphology that precludes the optimization of the material multifunctional properties. Basically, the cheap and easy-to-fabrication approach is constituted by a few steps. Firstly, either sacrificial acrilonitrile butadiene styrene (ABS) or poly(vinyl alcohol) (PVA) templates are 3D printed; successively they are infiltrated either with a neat ultra-soft silicone or with the same elastomer properly loaded with MLG; the ABS (PVA) is then leached in acetone (water) and the final structured polymer foam coated with a MLG film. Electrical, mechanical, thermal and piezoresistive tests together with morphological analyses will be used to develop a multi-physics model able to predict the resistance variation of the foams caused by cyclic applied stresses and attributable to the local modifications of the MLG percolative network. An ad-hoc electronic interface with excitation, conditioning circuits to boost the signal-to-noise ratio will be built and used to wirelessly transfer the output of the sensor module, after calibration, to a mobile phone thus verifying the feasibility to monitor remotely and in real-time different signals (i.e., pressure, strain).
