Executive Summary : | Flexible sensors have the potential to provide ultrahigh levels of sensitivity in detection of mechanical inputs such as strain, pressure, force, temperature and so on. These sensors are especially suited to human health monitoring applications due to their wearable characteristics. The flexible sensors are expected to mimic the human skin and its functions. The flexible sensors in comparison to traditional sensors can bend, roll, twist and fold without affecting their working. The advancement of novel fabrication techniques along with the use of polymer materials has promoted the development of flexible sensors. This project aims to develop ultrasensitive flexible sensors for human heath monitoring applications by detecting vital signals such as breathing, pulse-rate, motion, voice, and temperature. An efficient integration of the sensor with Internet-of-things (IoT) wireless technologies to achieve remote, wireless and point-of-care application features are some of the important unmet challenges. The sensors would be made of a soft and flexible polymer matrix such as PDMs and PANI, mixed with conductive filler particles such as Ag nanoparticles and CNTs. The sensors would utilize piezoresistive detection phenomenon, wherein the electrical resistance of a conductor changes when strained. The sensors would be fabricated using electrospinning-based 2D design and monolith flexible foam-based 3D design. By incorporating a conductive particle distribution inside, a percolation network can be created and piezoresistive properties can be imparted. The sensitivity of the sensors is determined by its gauge factor, which is defined as the ratio of change in electrical resistance per unit strain. Necessary synthesis process optimization and design optimization studies would be conducted to achieve the highest gauge factor. sensors would be characterized for its morphological, mechanical, and electro-mechanical properties for different filler contents. A phenomenological model would be developed to relate the resistance change to mechanical input in form of strain, pressure, force etc. As an application, the sensors developed would then integrate with IoT-based wireless technologies preferably Bluetooth to demonstrate point-of-care human health monitoring application features of the developed system. |