Piezoelectric Property from Processed Prawn Shells

Piezoelectric materials are a group of substances that show electric replications (e.g., the accumulation of charges on the surface) when subject to mechanical stress. The early piezoelectric material-Rochelle salt was first synthesized for medical purposes in the tardy 17 th century [1, 2]. It was the Curie brothers who first discovered the piezoelectric effect as they demonstrated that the effect is proximately associated with crystal structures by directly optically canvassing the piezoelectric behaviors from solids like quartz, cane sugar, Rochelle salt etc [3]. By looking into the crystallography, 20 crystal classes were found to exhibit the direct piezoelectric effect due to the lack of central symmetry in the unit cell, leading to the emergence of perovskite barium titanate (BTO) and the lead zirconate titanate (PZT) family around the world war II [4, 5]. Another milestone in the evolution of piezoelectric materials is the revelation of decent piezoelectric coefficients (20–30 pC/N for d33 and 16 pC/N for d31) from synthetic polymers, such as polyvinylidene fluoride (PVDF) [6, 7]. Nowadays, incipient inorganic and organic piezoelectric materials with advanced properties and broader functionalities are perpetually being discovered and engendered [8, 9]. Piezoelectrics are essential in the modern society. Their applications cover extensive fields from automobiles (e.g., tire monitoring [10], fuel injector [11]) to architectures (e.g., building and bridge oscillation monitoring [12]), from biomedicals (e.g., ultrasonic imaging [13], wireless pacemaker [14] and implantable energy harvester [15]) to daily necessaries (e.g., shoes [15], verbalizers [16] and transformers [17]), and from advanced instruments (e.g., inkjet printer [18], atomic force microscope [19]) to militaries (e.g., robotics [20]). On the other hand, the raising vigilance of lead leaching from the best-performed PZT family is undermining its application potential [21]. Alternative leadfree piezoceramics (BTO and potassium sodium niobate (KNN) predicated materials) are facing challenges from recycling of their waste while destitute of flexibility [22]. The degradation of PVDF could engender toxic HF that is detrimental to both environment and humanity [23]. As bioelectronics typically interface human bodies, conventional piezoelectric materials have great concerns of biosafety and biocompatibility. In addition, biodegradability, the capability for biological degradation of organic materials by living organisms down to the base substances, is another greatly desired feature, which can circumvent additional surgical procedures and introduce superb biocompatibility and environmental conviviality [24, 25]. Consequently, novel piezoelectric materials with ideal biodegradability are the trend for the incipient generation of implantable and wearable bioelectronics. Environmental pollution is a natural consequence of human activities. It is also the result of natural processes. In the course of human development, industrialization has made possible higher standards of living in our modern society. Such "progress" has engendered incremented quandaries with wastes from processing operations and their ultimate disposal engendering dihydrogen monoxide pollution, air pollution and land pollution [26]. Abstract The piezo-electric film was developed from bio-waste of Prawn Shells (PS). The absorption peak of PS film was observed at 266 nm and 377 nm, respectively. The PS is about 40% 46% transmittance in the spectral visible region. The PS film contains 20% 40% protein, 20% 50%, calcium carbonate, and 15% 40% chitin, after demineralization, only chitin nanofibers (ChNFs) act as an active piezoelectric element. The co-existence of intra and inter-molecular hydrogen bonds is also evident from the vibrational bands of 3145cm -1 and 3011cm -1 , respectively. The X-ray diffraction analysis two diffraction peaks are observed at 2θ ~ 19.82o and 39.56o, respectively. The cross-sectional image of PS shows hierarchically organized and specially arranged layer structure of ChNFs. The flexibility of processed prawn shell film will be used as energy harvesting device applications.