Desarrollo de sensores flexibles piezorresistivos basados en polímeros dopados con nanoestructuras de carbono para aplicaciones biomédicas

Abstract

In recent years, flexible electronics have been proposed as an alternative to traditional rigid electronics for the next generation of smart devices in biomedical, aerospace, sports, and automotive applications. In particular, the COVID-19 pandemic, the aging population of developed countries and the commitment to the Sustainable Development Goals have focused efforts on low-cost and easily accessible medical devices. Given this, flexible piezoresistive sensors emerge as a viable option to monitor human health accurately from a remote location. However, several challenges related to the design and optimization of these sensors still need to be overcome for their practical implementation. In the present PhD Thesis, high performance piezoresistive flexible sensors based on flexible polymeric matrices doped with carbon nanostructures have been developed for the biomedical industry. Specifically, six composite materials formed by flexible matrices of poly(ethylene glycol) diglycidyl ether (PEGDGE), polydimethylsiloxane (PDMS) or EcoflexTM (a platinum-catalyzed vinyl silicone)reinforced with carbon nanotubes (CNT) or graphene nanoplatelets (GNP) have been studied. This Doctoral Thesis has been presented as a compendium of 10 scientific papers, presented from chapter 4 to chapter 13, where the performance parameters of the different sensors are evaluated, the impact of temperature and hydrothermal conditions on these parameters is analyzed, as well as the study of the electrical behavior in direct and alternating current. The optimized ultrasensitive sensors have demonstrated their applicability in the biomedical industry with several proofs of concept. Joint movements, footprint distribution, small facial movements, wrist or neck, as well as human breathing have been recorded. In addition, human breathing has been monitored remotely with a conventional mask (via Bluetooth or Wi-Fi by connecting it to an Internet of Things platform), which opens up the possibility of monitoring vital parameters on a central server so that people can be monitored and controlled in real time in hospitals, residences or private homes.