Flexible Pressure Sensor for Continuous Physiological Monitoring

The field of bioelectronics has witnessed remarkable advancements in recent years, playing a crucial role in biomedical applications such as home-based monitoring of blood pressure and blood glucose levels. To expand the potential of bioelectronics, researchers have focused on developing advanced pressure sensors capable of monitoring various health parameters, including intraocular glaucoma, tendon repair and cardiovascular health. Meeting the growing demand for accurate pressure measurements, a multitude of flexible sensing technologies have been devised. These technologies employ techniques such as capacitive, piezoelectric, and piezoresistive sensors to convert external pressure into measurable signals. The success of these mechanical sensors hinges on their ability to compress under applied pressure. Notably, studies have demonstrated that capacitive pressure sensors outperform other options in faithfully reproducing the desired sensing behavior. Capacitive pressure sensors operate by detecting changes in initial capacitance caused by applied pressure. These sensors consist of a dielectric layer sandwiched between two parallel conductive plates. The sensitivity of these sensors increases with higher capacitance. Increasing capacitance can be achieved by reducing the plate distance or selecting a material with a high dielectric constant. This study aims to assess and compare the sensitivity of capacitors using five distinct viscoelastic polymers. The selection of these materials is guided by several factors, including their general properties such as biocompatibility, thermal stability, and cost-effectiveness. Moreover, their mechanical properties, such as high compressibility, low hysteresis, and high tensile strength, are carefully considered. These characteristics are crucial in determining the suitability of the polymers for capacitive pressure sensors, as they directly impact the sensor's performance and reliability. By leveraging these insights and engineering the materials and designs, the sensitivity and overall performance of capacitive pressure sensors can be significantly improved, paving the way for more precise and reliable biophysical pressure measurements in various biomedical applications.