Early epoxy vitrimers in the literature rely on an inequivalent epoxy/anhydride stoichiometry and a large amount of catalyst to achieve a decent transesterification rate within the crosslinked network. This design approach raises a number of concerns such as poor miscibility of the catalyst with other ingredients, poor mechanical properties owing to insufficient crosslinking, the toxicity of the catalyst, etc. In this study, a hydroxyl-amine compound, triethanolamine (TEOA), is incorporated as a catalytic co-curing agent to a typical BPA epoxy–cyclic anhydride curing system to give a TEOA-mediated covalent adaptable network system. The hydroxyl groups and tertiary amine of TEOA catalyze the curing process, and the tertiary amine and the regenerated hydroxyls in the crosslinked network accelerate dynamic transesterification. The resulting epoxy vitrimer exhibits a high glass transition temperature (∼135 °C), excellent tensile strength (∼94 MPa), and fast repairing rate (10 min at 190 °C). Recycling of the TEOA-mediated epoxy vitrimer and reuse of the recyclate are also studied. In an experiment, the vitrimer is ground into powder, and in another, it is degraded in an aqueous solution. The recyclates collected from both experiments are incorporated into the fresh resin, and the new vitrimer materials exhibited similar T gs and moduli to that of original vitrimer samples. This work provides a solution to eliminate the performance gap between conventional epoxy and epoxy vitrimer and offers simple recycling methods of epoxy vitrimer for new epoxy.

Due to the intrinsic properties of fabrics, fabric‐based wearable systems have certain advantages over elastomeric material‐based stretchable electronics. Here, a method to produce highly stretchable, conductive, washable, and solderable fibers that consist of elastic polyurethane (PU) fibers and conductive Cu fibers, which are used as interconnects for wearable electronics, is reported. The 3D helical shape results from stress relaxation of the prestretched PU fiber and the plasticity of the Cu fiber, which provides a predictable way to manipulate the morphology of the 3D fibers. The present fibers have superior mechanical and electrical properties to many other conductive fibers fabricated through different approaches. The 3D helical fibers can be readily integrated with fabrics and other functional components to build fabric‐based wearable systems.

In comparison with the implantable electronics, ingestible electronics are less invasive but can travel close to major organs through the gastrointestinal (GI) tract, monitor a wide range of biomarkers and therapeutic targets, and serve as effective clinical tools for diagnostics and therapy. [4d,5] Today, GI conditions have become one of the most prevalent health concerns in modern society. The market was expected to nearly reach the one-billion-dollar mark. [4e] Through analyzing the conditions of the GI tract [4d] (Figure 1), many diseases can be monitored and diagnosed, e.g., refluxing gastric fluid, cancer, motility disorders, infected and abnormally dilated venous vessels, gastritis, gastric ulcers, coeliac disease, lactose intolerance, Crohn's disease, inflammatory bowel disease, diverticular disease, constipation, clostridium difficile-associated diarrhea, irritable bowel syndrome, etc. [5,6] Conventional ingestible electronics mostly consist of inorganic materials and encapsulated with rigid nondegradable polymer, such as polydimethylsiloxane, parylene/epoxy, [4a] which will lead longer devices retention in the GI tract. This is one of the most significant risk elements during the application of conventional ingestible electronics. Fully food-based edible and nutritive electronics have emerged to address these potential risks. Edible electronics are new generation ingestible electronics. Recently, there is no accurate and clear definition of edible electronics. [4g,7] The definition of "transient electronics," [3h] which focused on implantable electronics, was similar to the edible electronics concept and defined as: made of biodegradable materials and can completely or partially dissolve, resorb, or physically disappear after functioning in environmental or physiological conditions at controlled rates. By follow this spirit, the definition of edible electronics is provided here: a class of microencapsulated electronic devices that consist of edible and nutritive inorganics and organics materials, meanwhile, that can be mainly dissolved, digested and absorbed after fulfilling the diagnosis or therapy of diseases in the gastrointestinal tract. The edible and nutritive inorganics always include edible inert metals, trace elements [8] and their oxides. Nutritive organics always include biopigments, and polymers. [7,9] A more systemic and expanded materials toolbox will be very helpful to advance The emerging novel edible and nutritive electronics indicate an important advance in ingestible and implantable electronics, covering multiple disciplines such as biomedicine, electronics, and nutriology. This review focuses on the feasibility and critical technical problems of fabricating fully edible and nutritive electronics. Recently, a limited number of fully edible and nutritive electronics, operating single functions, have been applied to monitor the condition of the gastrointestinal (GI) tract and diagnose its disorders. However, fully edible, nutritive, miniaturized, and well-functioning electronics with mu...

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