Introduction of Triboelectric Positive Bioplastic for Powering Portable Electronics and Self-Powered Gait Sensor

Abstract

Triboelectric nanogenerators (TENGs) are in the center of alternative energy scavenger technologies because of numerous possible applications in remote energy harvesting and self-powered sensing. Although there exists a large number of triboelectric negative polymers, the choice of triboelectric positive polymers is indeed limited. Here we report for the first time the use of thermoplastic starch (TPS) as a triboelectric positive material for designing TENGs. Our bioplastic-based highly durable TENG (b-TENG) can generate open-circuit peak-topeak output voltage of ∼560 V with output current density of ∼120 mA m −2 and instantaneous output power density of 17 W m −2 . We demonstrate b-TENG as a portable power source by powering more than 100 commercial blue LEDs, LED strips, and seven segment LCD screens. Additionally, the b-TENG can be used as a self-powered pedometer for step counter, a speedometer for human walking and running, and a human gait analysis sensor to assess physical activity breeding its futuristic biomedical applications for healthcare purposes. The introduction of ecofriendly bioplastic TPS as a triboelectric positive component has great potential for biomedical applications because of the abundance, biodegradability, low cost, and ease in fabrication process.

Wearable triboelectric sensors for biomedical monitoring and human-machine interface

“…Body movement monitoring plays an important role in daily life especially for sports training, medical diagnosis/rehabilitation, and security ( Cui et al., 2019 ; He et al., 2018a ; Lin et al., 2018 , 2019 ; Zhang et al., 2019b ; Zou et al., 2019 ). In these particular applications, the flexibility, stretch ability, and shape-adaptability of sensor are essential for keeping signals stable and device available ( Alam et al., 2020 ; An et al., 2018 ; Gogurla et al., 2019 ; Han et al., 2019 ; Liu et al., 2018 ; Ma et al., 2020 ; Sarkar et al., 2019 ). In this part, five examples based on different fabrications are reviewed: first, a flexible sensor assembled with serpentine-patterned electrodes and wavy-structured Kapton film for detecting the pressing and stretching force in human motions ( Yang et al., 2015b ); second, an environmentally friendly hydrogel-based tube-shaped TENG for sensing human motions ( Xu et al., 2017 ); third, a shape-adaptive sensor based on a rubber strap covered conductive liquid for biomechanical monitoring ( Yi et al., 2016 ); fourth, a textile-based TENG sensor for gait monitoring ( Jao et al., 2018 ); fifth, a highly resilient 3D-braided TENG as e-textiles for motion monitoring ( Dong et al., 2020b ).…”

Green flexible electronics based on starch

“…5c) 122 . The 0.5% of CaCl 2 was added into the film to improve the voltage output from 0.4 to 1.2 V. Sarkar and co-workers 40 developed TENGs using thermoplastic starch film as a positive electrode and PDMS as negative electrode (Fig. 5d).…”

“…For instance, Sarkar et al 24,26 . prepared triboelectric nanogenerator based on thermoplastic starch 39,40 . Such products are increasingly favored by more and more applications, but their development is still in the infancy stage.…”

“…Among the reported sustainable materials used in FEs, starch have advantages on the acceptable solubility in water, good property of film forming and relative low cost comparing with cellulose, lignin and proteins. Therefore, a lot of efforts have been put into the developments of FEs based on starch [37][38][39][40][41] , in which the starch usually appeared as films or gels. The starch films were often used as soft and transparent substrates because of the intrinsic good film-forming property of starch.…”

Polysaccharide-based triboelectric nanogenerators: A review

“…A high-output corn starch-based TENG was developed by Sarkar, Kamilya, and Acharya (2019). This TENG consisted of a 0.15 mm thick corn starch and 0.20 mm PDMS films as dielectric layers coupled to carbon tapes as electrodes in a vertical contact-separation mode.…”