Real-time diagnosis of small energy impacts using a triboelectric nanosensor

Abstract

Recently, triboelectric nanogenerators (TENGs) are generating increasing interest due to their important applications as energy harvesters and self-powered active sensors for pressures, vibrations and other mechanical motions. However, there is still little research within the research community on their potential as selfpowered impact sensors. This paper considers the development of a novel triboelectric nanogenerator, which is prepared using a simple and economic fabrication process based on electrospinning. Furthermore, the paper studies the changes in the generated electric response caused by small energy impacts. For the purpose, the TENG electric outputs generated by the impact of a free-falling ball dropped from different heights are investigated. The idea is to investigate the relation between the electric responses of the nanogenerator and the energy of the impact.The experimental results demonstrate that the voltage and current outputs increase linearly with the increase of the impact energy. Moreover, the electric responses of the triboelectric nanogenerator show a very high sensitivity (14 V/J) to the changes in the impact energy and good repeatability. The main achievements of this paper are in the development of novel triboelectric nanogenerator composed of polyvinylidene fluoride nanofibers and a thin film of polypropylene, and its successful application as an impact sensor for real-time assessment of small energy impacts. 2 1 Introduction An impact sensor plays a critical role in vehicle safety, fast medical assistance of elderlies and structural health monitoring. For example, in the event of a car crash an impact sensor detects the collision to release an air-bag for the protection of the passengers. In the case of falls in the elderly, an impact sensor can be used to inform about the accident and provide a fast-medical assistance. Other practical examples could be detection of impacts in hail storms, where impacts are responsible for a considerable number of accidents in aircrafts, wind turbines and other civil infrastructures. Therefore, the sensing and the quantification of impacts is of vital importance for a number of applications as impacts can seriously affect the health and safety of humans. Recently, various approaches have been developed and applied for detection and measurement of impacts in environment as for example piezoelectric sensors [1, 2], capacitive sensors [3], optical sensors [4], acoustic sensors [5] and vibration sensors [6]. Special attention deserves the works of Yang's group [7, 8] which investigates the applications of flexible piezoelectric sensors for detection and measurement of pressures, which can be used for important applications as sleeping monitoring, tactile measurements, or sensing of human heartbeats. Additionally, other authors as [9]investigated the potential of piezoelectric nanogenerators as acceleration sensors for real-time collision monitoring, which has important applications as vehicle safety monitoring. However, most of these technologies require...

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