Conducting polymers in wearable devices

Abstract

The increase interests in wearable device market are triggered by healthcare monitoring. Common examples are pulse, heart rate and temperature monitors. Wearable technology has opened up new path for non-invasive diagnostic and therapeutic technologies via sensing of biomarker/drug from the liquid extracted on skin including sweat (Bandodkar & Wang, 2014; Liu et al., 2017). The increasing demand of integrating electronic technology in wearable devices is driven by needs for individual monitoring remotely at home, often called as ubiquitous health care (Choudhuri et al., 2019). In addition, wearable devices allow continuous, long time monitoring at any place, anytime (Bohr et al., 2019). Mechanical and electrical responsive conducting polymers (CPs), plus high flexibility and stretch-ability contribute to recent accelerate growth of publications involving conducting polymer in wearable and skin-attachable device. Metals and silica (semiconductors) are inorganic materials that are generally regarded as highly conductive but are rigid and inflexible. The concept of organic conductors/semiconductors has arisen since the discovery of highly conducting polyacetylene by Hideki Shirakawa, working along with Alan MacDiarmid and physicist Alan Heeger in 1977 (Shirakawa et al., 1977). The most apparent advantage of organic electronics as compared to inorganic is that they are highly flexibility and they are lightweight. These properties are ideal for wearable sensors. Conducting polymers with long-term electrical and chemical stability such as polypyrrole (PPy), poly(3,4-ethylenedioxy-thiophene) (PEDOT) and polyaniline (PANi) (Figure 1) have gained popularity in this field (Puiggali-Jou et al., 2019; Talikowska et al., 2019). Doping counterions in close proximity to the extended pi-bond significantly improve CP conductivity. These doped CPs have electrical conductivities ranging from >1 S/cm to >1000 S/cm aligning CPs with the inorganic semiconductors, for example silicon

Oxygen Gas Sensing Using a Hydrogel-Based Organic Electrochemical Transistor for Work Safety Applications

“…Nowadays, there is heightened interest in wearable technologies, as highlighted by several reviews, reporting up-to-date advances and implementation of chemical, gas and pressure/strain sensors aiming at meeting the above mentioned needs [ 13 , 14 , 15 , 16 ]. Among these sensors, conducting polymer-based devices have been recently investigated due to their flexibility, stretchability and low-cost which allow the production of comfortable devices suitable for daily use [ 17 , 18 , 19 ].…”

PEDOT Composite with Ionic Liquid and Its Application to Deformable Electrochemical Transistors

“…PEDOT:PSS doped with anionic PSS in the semiconducting polymer PEDOT has both electrical and ionic conductivity, facilitating low electrochemical impedance properties under various solid or liquid electrolyte environments. Owing to this bio-friendly charge transport property, PEDOT:PSS is widely used as a conducting material for electrode devices and a channel material in various OECT devices for biosensors and electrophysiological sensors [ 27 , 28 , 29 ]. However, PEDOT:PSS cannot easily achieve conformal and adaptive integration with bio-tissues due to its intrinsically low deformability [ 30 , 31 ].…”

Intrinsically Stretchable Poly(3,4-ethylenedioxythiophene) Conducting Polymer Film for Flexible Electronics

“…The concept of organic conductors/semiconductors has been a hot topic since the discovery of the first conductive polymer (CP) polyacetylene in 1977 [6]. The most obvious advantage of organic electronics over inorganic ones is that they are very flexible and lightweight, which are ideal properties for wearable sensors [7]. CPs have been introduced as one of the classes of organic polymers with metallic or semiconducting properties, such as electrical, magnetic, optical, and electronic properties, while at the same time maintaining the characteristics of conventional organic polymers, such as easier synthesis, lower cost, light weight, and corrosion resistance [8][9][10][11].…”

“…CPs have been introduced as one of the classes of organic polymers with metallic or semiconducting properties, such as electrical, magnetic, optical, and electronic properties, while at the same time maintaining the characteristics of conventional organic polymers, such as easier synthesis, lower cost, light weight, and corrosion resistance [8][9][10][11]. These properties have led to an increasing trend of using conducting polymers for wearables [7,12]. These materials can be either insulators or semiconductors in a neutral or undoped form, which can be converted to a doped form by a redox reaction to form delocalized charge carriers.…”