Whey Protein Isolate Film and Laser-Ablated Textured PDMS-Based Single-Electrode Triboelectric Nanogenerator for Pressure-Sensor Application.

Minwoo Lee,Sunkook Kim,Jonghwan Shin,Srinivas Gandla

doi:10.3390/s22062154

Abstract

The use of biopolymers for realizing economical and eco-friendly triboelectric nanogenerators (TENGs) widens the application prospects of TENGs. Herein, an animal-sourced whey protein isolate (WPI) film, processed and prepared by a simple aqueous solution preparation and drop-casting technique, is applied to demonstrate its potential use in bio-TENGs. With the addition of formaldehyde in WPI, the films result in a free-standing and flexible film, whereas the pure WPI films are difficult to handle and lack flexibility. A TENG device based on the WPI and the laser-ablated textured polydimethylsiloxane (PDMS) for pressure-sensor application were developed. The output voltage of the TENG comprising WPI increased nearly two-fold compared to the TENG without WPI. A simple single-electrode TENG device configuration was adopted so that it could be easily integrated into a wearable electronic device. Moreover, WPI film exhibited tribo-negative-like material characteristics. This study provides new insights into the development of biocompatible and eco-friendly biopolymers for various electronic devices and sensors.

Highlights

An animal-sourced Whey protein isolate (WPI) film derived from milk was successfully applied for potential use in bio-triboelectric nanogenerators (TENGs)
The WPI film exhibited tribo-positive material-like characteristics when subjected to mechanical loads with PDMS, a tribo-negative material
Benefitting from the relative higher triboelectric voltage among the WPI and PDMS, a TENG device comprised of WPI and laser-ablated rough PDMS for pressure-sensor application was successfully demonstrated with a maximum sensitivity of 1.61 V kPa−1 in the linear region

Summary

Introduction

Biopolymers using eco-friendly, sustainable, clean, and renewable natural materials that are biocompatible and/or biodegradable are crucial for any kind of electronics or materials research field [1,2]. These polymers in electronic devices can substantially eliminate the global problem of electronics waste, leading to a friendly environment. TENGs are devices that convert any form of mechanical energy available in the environment into electrical energy [7] Their uses are not limited to energy generation as they are useful for self-powered sensing [8–12]. The commercially available WPI powder products are soluble in an aqueous solution, and they could possibly be used to form films with a simple drop-casting method. Whey protein biomaterial for TENGs could certainly enable the development of low-cost devices for various sensing applications

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Conclusion