Flexible and stretchable printed conducting polymer devices for electrodermal activity measurements

Abstract

Highly stretchable and flexible bioelectronics should form close contact with skin and tissues while being able to withstand the stresses and strains endured by the body in order to reliably monitor physiological signals over time. Here, we report highly stretchable poly 3,4-ethylenedioxythiophene: polystyrene sulfonate (PEDOT:PSS) films printed on thermally resistant polyurethane (TPU) substrates. We established the stability of the conductivity of the devices under high strains up to 600%. The printed PEDOT:PSS film enabled the fabrication of printed organic electrochemical transistors (OECTs) with an ON/OFF ratio of 450 on a flexible substrate. We also acquired physiological signals from measuring the skin conductance arising from changes in sweat volume by directly interfacing a printed PEDOT:PSS-based sensor on TPU with human skin. Stretchable printed PEDOT:PSS films on TPU provide a facile method of producing highly stable stretchable sensors for bioelectronic applications, enabled with simple and direct printing fabrication.

All-printed and stretchable organic electrochemical transistors using a hydrogel electrolyte

“…OECTs were patterned on the stretchable TPU substrates with a PCB printer (Voltera V-One), already used by our group to pattern devices on flexible polyethylene terephthalate. 50 The TPU substrates were cleaned with deionized water (DIW), dried using an air-blowing gun and attached to a glass slide (Corning®) with double-sided tape (3 M) to facilitate handling. The stretchable Ag ink, used to pattern gate, source and drain electrodes, was homogenized in a sonicator (CPX2800, Fisherbrand™) for 15 min before use.…”

“…The initial changes in the drain current are consistent with the resistance change of stretched PEDOT:PSS films in our previous work. 50 The sudden current changes after 5000 s, are likely related to the stretchable Ag interconnects. According to the magnified plot of the multiple-cycle stretchability tests (Fig.…”

“…In our previous work, a similar test at 30% cyclic strain was conducted with PEDOT:PSS films printed on the TPU substrate without the Ag electrodes and no spikes were observed. 50 The spikes might be alleviated by patterning serpentine interconnects and replacing the Ag with conducting polymer interconnects. 39 We summarized the main device parameters of some examples of all-printed OECTs found in the literature along with our results in Table 2.…”

Fully Screen‐Printed Stretchable Organic Electrochemical Transistors

“…[27] The growing interest in wearable technology has driven the development of stretchable electronics to improve the integration of electronics with the soft and deformable human body. [28,29] Major efforts have been put into making conducting polymers stretchable, including addition of plasticizers, [30,31] elastomer composites, [32] and tailored molecular design. [33,34] Stretchable OECTs have been developed based on nonscalable methods like transfer patterning and/or spin-coating and microcracked thin gold films, [35][36][37] pre-straining of substrates, [38,39] and lamination.…”

Preparation and performance optimization of resistive flexible temperature sensors prepared by inkjet printing method

“…Abnormal body temperature might be a symptom of illness [2][3][4]. Consequently, it is vital to utilize real-time and accurate temperature sensors to detect the human body temperature [5,6]. Traditional temperature monitoring devices, such as mercury thermometers, electronic thermometers, and forehead temperature guns, cannot meet the requirements of monitoring curved surface temperature [7][8][9].…”