Highly Enhanced Triboelectric Performance from Increased Dielectric Constant Induced by Ionic and Interfacial Polarization for Chitosan Based Multi‐Modal Sensing System

Abstract

The coexistence of increasingly severe environmental concerns and bio-signal sensing systems drives the development of environmental affinity and energy harvesting materials. Chitosan is a richly sourced biodegradable material derived from crustaceans, which provides a new option for environmentally, wearable triboelectric nanogenerator (TENG). In this paper, the triboelectric performance of chitosan blends are proposed to enhance the dielectric constant by optimizing the ionic polarization and interface polarization for the first time, which fills in the blank of enhancing the output of chitosan triboelectric by systematically engineering in ionic/molecular and pH effect. Triboelectric output enhanced chitosan film in TENG shows an output voltage 3 times (18 V) higher than that of the initial film and 25 times (200 V) higher after corona charge injection. The chitosan film for wearable devices not only can be used as a unit of a triboelectric device to measure human motion signal, but also can be used as a piezoresistive sensor (ΔR/R 0 : 0 to 1.5) and an air humidity sensor (relative humidity: 20% to 90%) after mixing carbon black. The study provides a stimulating example that triboelectric nano generator/piezoresistive sensor is made from chitosan and used in the multi-modal sensing system.

Enhancing Strain-Sensing Properties of the Conductive Hydrogel by Introducing PVDF-TrFE

“…Compared with other chitosan hydrogel sensors, the GF of Pp-hydrogel has obvious advantages. Compared with the hydrogel sensor based on chitosan and its derivatives as framework (Figure e), the Pp-hydrogel also has advantages. ,,,,,− ,,− …”

“…On the one hand, there are various options for hydrogel matrix materials. The raw materials of hydrogels can be derived from synthetic polymers − and natural polymers. − In contrast, natural polymers such as chitosan − are derived from renewable biochar materials, which have the characteristics of biocompatibility, biodegradability, biostability, abundance, and good hydrophilicity, and can be used to prepare environmentally friendly, cost-effective hydrogels. The amino groups and hydroxyl groups on the side groups of the chitosan backbone can be further functionalized, and the obtained chitosan quaternary ammonium salts can easily form intermolecular hydrogen bonds.…”

Cooperativity of Silver Nanostructures upon Electric Power Generation in Triboelectric Polyimide Layers

“…The enhanced dielectric constant of PI film is due in large part to the fact that incorporation of the conductive fillers into nonconductive film drives to accumulate the charges at their interfaces under external fields, serving as a series of microcapacitor in the nonconductive film. [30,31] At 1 Hz corresponding to the frequency of typical mechanical stimuli in nanogenerators, the dielectric constant of the composite film is 3.20 in the presence of 0.16 mg mL À1 AgNPs, and this value increases to 5.43 with 0.35 mg mL À1 AgNRs (Figure S3, Supporting Information). It is important to note that the dielectric constant of composite films is greatly varied with the geometrical parameters of the conductive Ag fillers.…”

Direct-Current Triboelectric Nanogenerators Based on Semiconductor Structure

“…Triboelectrification has gradually become a mainstream energy collection technology, and this phenomenon has attracted the attention of researchers. − The generation of a time-varying electric field in TENGs is caused by surface static charges induced by the contact of two materials of different polarity consequently driving electrons to flow in the external circuit to form a current. , The working modes of TENGs are divided into four types: vertical contact–separation mode, horizontal sliding mode, single electrode mode, and independent layer mode. − The structure, surface microstructure (surface morphology), and triboelectric materials are three factors that affect the output performance of TENGs. − In order to improve the output performance and mechanical properties of TENGs, this review mainly discusses TENGs with different structures and materials. In general, the traditional research on TENGs mainly focused on triboelectrification between organic polymer insulator materials, which tend to generate alternating current (AC). − They are limited by low current density and rectification requirements. , Many strategies to increase the current density have been tried, like chemical modification, ion injection, and using materials with micropatterns. − Some examples are listed in Table . Nevertheless, friction materials treated by these methods tended to be less stable.…”