A Highly Conducting Polymer for Self‐Healable, Printable, and Stretchable Organic Electrochemical Transistor Arrays and Near Hysteresis‐Free Soft Tactile Sensors

Abstract

A stretchable and self‐healable conductive material with high conductivity is critical to high‐performance wearable electronics and integrated devices for applications where large mechanical deformation is involved. While there has been great progress in developing stretchable and self‐healable conducting materials, it remains challenging to concurrently maintain and recover such functionalities before and after healing. Here, a highly stretchable and autonomic self‐healable conducting film consisting of a conducting polymer (poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS) and a soft‐polymer (poly(2‐acrylamido‐2‐methyl‐1‐propanesulfonic acid), PAAMPSA) is reported. The optimal film exhibits outstanding stretchability as high as 630% and high electrical conductivity of 320 S cm−1, while possessing the ability to repair both mechanical and electrical breakdowns when undergoing severe damage at ambient conditions. This polymer composite film is further utilized in a tactile sensor, which exhibits good pressure sensitivity of 164.5 kPa−1, near hysteresis‐free, an ultrafast response time of 19 ms, and excellent endurance over 1500 consecutive presses. Additionally, an integrated 5 × 4 stretchable and self‐healable organic electrochemical transistor (OECT) array with great device performance is successfully demonstrated. The developed stretchable and autonomic self‐healable conducting film significantly increases the practicality and shelf life of wearable electronics, which in turn, reduces maintenance costs and build‐up of electronic waste.

High-Transconductance, Highly Elastic, Durable and Recyclable All-Polymer Electrochemical Transistors with 3D Micro-Engineered Interfaces

“…This change can be attributed to the extension of the distance between the channel and gate regions produced by stretching, thus reducing the effective electric field for ion motion. Therefore, the changes in device geometry that occur during stretching in the solid-state OECT may be a critical concern in terms of performance variation [ 22 ]. Furthermore, the combination of the 3D-microstructured channel and the wrinkled electrodes was also capable of withstanding 1000 stretching cycles under 80% uniaxial strain, during which no significant reductions in I ON and G m were discovered for the first 400 cycles, and retention of ~ 95% of I ON and ~ 75% of G m was ultimately achieved after 1000 cycles (Fig.…”

“…For example, wrinkled metal electrodes [ 10 , 25 ] and metal grid arrays [ 26 ] were demonstrated to achieve stable transconductance (> 1 mS) under strains of up to ~ 30%. Microscopically cracked metal electrodes [ 27 ] and metal nanowires embedded in elastomers [ 22 ] could allow retained device performances with respect to strains of 50%. OECTs based on either in-plane [ 28 ] or out-of-plane [ 29 ] curved conducting polymer microwires and woven fabric structures [ 30 ] showed promisingly high stretchability, but the fabrication processes are complicated.…”

“…The lack of the highly stretchable conductors and semiconducting polymers required, along with the elastic gel electrolytes, has greatly hindered the development of mechanically robust OECTs that are capable of sustaining large strains of > 50% [17,18]. Major efforts have been devoted to developing stretchable poly (3,4-ethylenedioxyth iophene):poly(styrene sulfonate) (PEDOT:PSS)-based conducting polymers that exhibit steady electronic functionality under applied strains [19,20,21,22,23,24]. A few recent works also explored microstructures that were designed to improve the stretchability of OECTs.…”

Conducting Polymers for the Design of Tactile Sensors

“…In long-term applications, the ability of self-healing is highly important to the reduction in electronic waste to meet the requirements of environmental protection. Xiaoqian Su et al [ 78 ] described self-healing tactile sensor development based on the composition of such polymers as a conducting polymer (poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate), PEDOT:PSS) and a soft-polymer (poly(2-acrylamide-2-methyl-1-propanesulfonic acid), PAAMPSA). In such a tactile sensor, PAAMPSA was the polymer that was responsible for the self-healing feature and stretchability of the whole composition of polymers.…”

Tissue-like organic electrochemical transistors

“…Because of the potential for soft bioelectronic applications, tissue-like OECTs have become the research interest of more and more research groups in Canada, 15,29 the United States, [34][35][36][37] China, 38,39 Japan, 21 Korea, 40,41 Singapore, 32,37,42 Italy, 20 etc. Emerging research directions include, but not limited to, the design and processing of stretchable materials systems, 23,32,42 the development of advanced manufacturing technologies, 23,43 interface engineering, 27 the optimization of device performance and stability, 27,42 and the efforts toward system-level integration (Fig. 4).…”