Recent progress in flexible sensors and piezoelectric materials has enabled the development of continuous monitoring systems for human physiological signals as wearable and implantable medical devices. However, their non‐degradable characteristics also lead to the generation of a significant amount of non‐decomposable electronic waste (e‐waste) and necessitate a secondary surgery for implant removal. Herein, a flexible and biodegradable piezoelectric material for wearable and implantable devices that addresses the problem of secondary surgery and e‐waste while providing a high‐performance platform for continuous and seamless monitoring of human physiological signals and tactile stimuli is provided. The novel composition of bioresorbable poly(l‐lactide) and glycine leads to flexible piezoelectric devices for non‐invasive measurement of artery pulse signals in near‐surface arteries and slight movement of the muscle, including the trachea, esophagus, and movements of joints. The complete degradability of piezoelectric film in phosphate‐buffered saline at 37 °C is also shown. The developed pressure sensor exhibits high sensitivity of 13.2 mV kPa−1 with a response time of 10 ms and shows good mechanical stability. This piezoelectric material has comparable performance to commonly used non‐degradable piezoelectric materials for measuring physiological signals. It can also be used in temporary implantable medical devices for monitoring due to its degradable nature.

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<p>In this study, an advanced energy harvesting interface called synchronized switch harvesting on inductor (SSHI) has been integrated with a piezoelectric energy harvester on a plate-like structure for multimode energy harvesting purposes. To the best of author’s knowledge, this type of energy harvesting system has not been studied in the literature before. Analytical solution has been developed to predict the power output of the harvester. Besides, experiments have been performed to validate the analytical model predictions and evaluate performance of the circuit. The experimental results showed that the SSHI circuit has three different switching behaviour, namely, no switching, single switching, and multi-switching. Power output of the SSHI circuit has been compared with AC-DC rectifier. It was shown that the SSHI circuit improves the power output of the harvester for the first two vibration modes of structure in the single switching case. The SSHI circuit acts as a rectifier in no switching case. Finally, multi-switching dissipates the available energy of harvester and reduces the output voltage and power of the harvester.  </p>

Multimodal piezoelectric energy harvesting can be achieved by integrating piezo-patch harvesters into plate-like structures available in marine, aerospace, and automotive applications. A synchronized switch harvesting on inductor (SSHI) interface as the harvesting circuit has been well studied for cantilever beams, considering the single vibration mode of the structure. However, integrating a two-dimensional electromechanical structure with a SSHI circuit for multimodal energy harvesting is missing in the literature. This paper evaluates the performance of the SSHI interface integrated with a piezo- patch energy harvester (PEH) on a plate-like host structure. The analytical solution is developed based on an equivalent impedance approach to predict the steady-state electrical response of the harvester as a closed-form solution. The experiments are conducted to validate the analytical solution for the system's first and second vibration modes. The experimental results reveal that integration of SSHI to a plate-like harvester introduces a multi-switching behavior rather than a standard single-switching behavior. Due to the multimodal vibrational characteristics of the plate, the circuit switch is triggered several times at each half period of the vibration, which increases the energy dissipation of the circuit and thus reduces the output voltage. On the other hand, single switching at each half period of the vibration happens for lower piezoelectric voltage levels. This is the desired behavior of the SSHI circuit where the analytical prediction matches with the experimental data. Finally, the energy harvesting performance of the SSHI circuit is compared against the standard rectifier, showing 183% and 134% power output enhancement for the first and second vibration modes, respectively.&#xD;

<p>In this study, an advanced energy harvesting interface called synchronized switch harvesting on inductor (SSHI) has been integrated with a piezoelectric energy harvester on a plate-like structure for multimode energy harvesting purposes. To the best of author’s knowledge, this type of energy harvesting system has not been studied in the literature before. Analytical solution has been developed to predict the power output of the harvester. Besides, experiments have been performed to validate the analytical model predictions and evaluate performance of the circuit. The experimental results showed that the SSHI circuit has three different switching behaviour, namely, no switching, single switching, and multi-switching. Power output of the SSHI circuit has been compared with AC-DC rectifier. It was shown that the SSHI circuit improves the power output of the harvester for the first two vibration modes of structure in the single switching case. The SSHI circuit acts as a rectifier in no switching case. Finally, multi-switching dissipates the available energy of harvester and reduces the output voltage and power of the harvester.  </p>