ABSTRACT
Stretchable electrochromic devices (ECDs) were fabricated from electrospun PEDOT:PSS (poly(3, 4-ethylenedioxythiophene):polystyrene sulfonate) fibers. Stretchable and transparent electrodes with a sheet resistance of 1200 Ω sq-1were prepared by depositing the conductive fibers on elastomeric substrates that were prepared from polydimethylsiloxane. The conductive substrates replaced the ITO coated glass electrodes that are typically used in ECDs. The functioning device was prepared from a flexible chitosan electrolytic gel and a 4, 7-bis(4-diphenylaminophenyl)-2, 1, 3-benzothiaziazole (TPA-BZT-TPA) electrochrome that were deposited on the streatchable transparent electrodes. The assembled device could be stretched to 150% its original length and bent to a curvature of 0.1. The device could be operated and switched between its yellow (off) and blue (on) states while being stretched and bent with a maximum contrast ΔT ≈ 30% at 805 nm and a coloration efficiency of 168 cm2C-1. The stretchable device had an electrochromic contrast that was 30% greater than its counterpart that was prepared from conventional ITO-glass electrodes. The critical composition required for making devices truly stretchable was possible by evaluating the performance of five types of devices consisting of different layers.
ABSTRACT
The conducting polymer polyethylenedioxythiophene doped with polystyrene sulfonate (PEDOT:PSS) has received great attention in the field of wearable bioelectronics due to its tunable high electrical conductivity, air stability, ease of processability, biocompatibility, and recently discovered self-healing ability. It has been observed that blending additives with PEDOT:PSS or post-treatment permits the tailoring of intrinsic polymer properties, though their effects on the water-enabled self-healing property have not previously been established. Here, it is demonstrated that the water-enabled healing behavior of conducting polymers is decreased by crosslinkers or by acid post-treatment. Organic dopants of PEDOT have high water swelling ratios and lead to water-enabled healing, while inorganic dopants fail in the healing of PEDOT. The water-enabled healing of two isolated PEDOT:PSS squares with a 5 µm width gap and a thickness less than 1 µm is shown. This work will help pave the way for the further development of conducting polymer-based self-healable bioelectronics and flexible and stretchable electronics.
Subject(s)
Electric Conductivity , Polymers/chemistry , Bridged Bicyclo Compounds, Heterocyclic/chemistry , Polystyrenes/chemistry , Sulfuric Acids/chemistry , Time FactorsABSTRACT
Diazonium chemistry concomitant with in situ electrochemical reduction was used to graft an aryl aldehyde to indium-tin oxide (ITO) coated glass substrates. This served as an anchor for preparing electroactive azomethines that were covalently bonded to the transparent electrode. The immobilized azomethines could undergo multiple step-wise component exchanges with different arylamines. The write-erase-write sequences were electrochemically confirmed. The azomethines could also be reversibly hydrolyzed. This was exploited for multiple azomethine-hydrolysis cycles resulting in discrete electroactive immobilized azomethines. The erase-rewrite sequences were also electrochemically confirmed.
