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.

The ability to operate in aqueous environments makes poly(3,4-ethylenedioxyt hiophene):poly(styrenesulfonate), PEDOT:PSS, based organic electrochemical transistors (OECTs) excellent candidates for a variety of biological applications. Current research in PEDOT:PSS based OECTs is primarily focused on improving the conductivity of PEDOT:PSS film to achieve high transconductance (g m ). The improved conductivity and electronic transport are attributed to the formation of enlarged PEDOT-rich domains and shorter PEDOT stacking, but such a change in morphology sacrifices the ionic transport and, therefore, the doping/de-doping process. Additionally, little is known about the effect of such morphology changes on the gate bias that makes the maximum g m ( P Pe ea ak k V G G ), threshold voltage (V T ), and transient behavior of PEDOT:PSS based OECTs. Here, the molecular packing and nanostructure of PEDOT:PSS films are tuned using ionic liquids as additives, namely, 1-Ethyl-3-methylimidazolium (EMIM) as cation and anions of chloride (Cl), trifluoromethanesulfonate (OTF), bis(trifluoromethylsulfonyl)imide (TFSI), and tricyanomethanide (TCM). It is demonstrated that an optimal morphology is realized using EMIM OTF ionic liquids that generate smaller fibril-like PEDOT-rich domains with relatively loose structures. Such optimal morphology improves ion accessibility, lowering the gate bias required to completely de-dope the channel, and thus enabling to achieve high transconductance, fast transient response, and at lower gate bias window simultaneously.

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Ultrasound-enhanced drug delivery has shown great promise in providing targeted burst release of drug at the site of the disease. Yet current solid ultrasound-responsive particles are non-degradable with limited potential for drug-loading. Here, we report on an ultrasound-responsive multi-cavity poly(lactic-co-glycolic acid) microparticle (mcPLGA MP) loaded with rhodamine B (RhB) with or without 4′,6-diamidino-2-phenylindole (DAPI) to represent small molecule therapeutics. After exposure to high intensity focused ultrasound (HIFU), these delivery vehicles were remotely implanted into gel and porcine tissue models, where the particles rapidly released their payload within the first day and sustained release for at least seven days. RhB-mcPLGA MPs were implanted with HIFU into and beyond the sub-endothelial space of porcine arteries without observable damage to the artery. HIFU also guided the location of implantation; RhB-mcPLGA MPs were only observed at the focus of the HIFU away from the direction of ultrasound. Once implanted, DAPI co-loaded RhB-mcPLGA MPs released DAPI into the arterial wall, staining the nucleus of the cells. Our work shows the potential for HIFU-guided implantation of drug-loaded particles as a strategy to improve the local and sustained delivery of a therapeutic for up to two weeks.

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