| Summary: | Graphene, the base sp2 carbon form, has been acclaimed by the scientific community as a “wonder material” with enormous disruptive impact in a wide range of technological fields. Its discovery triggered the development of a whole new field in Physics and Materials Sciences, that of 2D materials, which is still growing past sixteen years. This field encompasses an array of subareas that exploit the outstanding thermal, electrical and mechanical properties of graphene, as well as new quantum phenomena made observable at easier experimental conditions due to the particular structure and topology of this material. This thesis aims at expanding one of these areas, that of mechanical transduction, with focus on sensorization technologies. With this goal, two graphene-based materials are studied: the 3D laser-induced graphene (LIG) foams and few-layer graphene films produced by chemical vapor deposition (CVD). Regarding LIG, in the field of sensors, piezoresistive devices are developed with higher spatial resolution and force-sensitivity than the competing literature alternatives. These sensors, produced in polyimide substrates by ultraviolet laser radiation, are explored for the detection of biophysical signals, namely the arterial pressure wave. New environment-friendly platforms to produce this material are also studied, namely cork, on which piezoresistive pressure sensors are developed to monitor the plantar pressure along the gait. In the field of actuators, the thermoacoustic effect is explored for the generation of sound, and the practical viability of the commercial use of devices using this transduction method is evaluated. The CVG-grown graphene films are explored to develop a new production technique able to suspend ten-layer graphene over cavities of up to four millimeters in diameter. These membranes achieve the highest suspended area per number of layers ratio found in the literature. The application of these millimeter sized films is demonstrated through the production of a wideband condenser microphone with increased specific response. The method developed to obtain suspended graphene through the sublimation of the transfer supporting layer is a technical solution that allows progresses in other diverse fields.
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