There is often a trade-off between mechanical properties (modulus and toughness) and dynamic self-healing. Here we report the design and synthesis of a polymer containing thermodynamically stable ...whilst kinetically labile coordination complex to address this conundrum. The Zn-Hbimcp (Hbimcp = 2,6-bis((imino)methyl)-4-chlorophenol) coordination bond used in this work has a relatively large association constant (2.2 × 10
) but also undergoes fast and reversible intra- and inter-molecular ligand exchange processes. The as-prepared Zn(Hbimcp)
-PDMS polymer is highly stretchable (up to 2400% strain) with a high toughness of 29.3 MJ m
, and can autonomously self-heal at room temperature. Control experiments showed that the optimal combination of its bond strength and bond dynamics is responsible for the material's mechanical toughness and self-healing property. This molecular design concept points out a promising direction for the preparation of self-healing polymers with excellent mechanical properties. We further show this type of polymer can be potentially used as energy absorbing material.
The electronic devices that play a vital role in our daily life are primarily based on silicon and are thus rigid, opaque, and relatively heavy. However, new electronics relying on polymer ...semiconductors are opening up new application spaces like stretchable and self-healing sensors and devices, and these can facilitate the integration of such devices into our homes, our clothing, and even our bodies. While there has been tremendous interest in such technologies, the widespread adoption of these organic electronics requires low-cost manufacturing techniques. Fortunately, the realization of organic electronics can take inspiration from a technology developed since the beginning of the Common Era: printing. This review addresses the critical issues and considerations in the printing methods for organic electronics, outlines the fundamental fluid mechanics, polymer physics, and deposition parameters involved in the fabrication process, and provides future research directions for the next generation of printed polymer electronics.
Bioelectronics for modulating the nervous system have shown promise in treating neurological diseases
. However, their fixed dimensions cannot accommodate rapid tissue growth
and may impair ...development
. For infants, children and adolescents, once implanted devices are outgrown, additional surgeries are often needed for device replacement, leading to repeated interventions and complications
. Here, we address this limitation with morphing electronics, which adapt to in vivo nerve tissue growth with minimal mechanical constraint. We design and fabricate multilayered morphing electronics, consisting of viscoplastic electrodes and a strain sensor that eliminate the stress at the interface between the electronics and growing tissue. The ability of morphing electronics to self-heal during implantation surgery allows a reconfigurable and seamless neural interface. During the fastest growth period in rats, morphing electronics caused minimal damage to the rat nerve, which grows 2.4-fold in diameter, and allowed chronic electrical stimulation and monitoring for 2 months without disruption of functional behavior. Morphing electronics offers a path toward growth-adaptive pediatric electronic medicine.
Lithium metal is a promising anode to provide high energy density for next-generation batteries. However, it has not been implemented due to its low cycling efficiency, which results from the ...formation of an unstable solid electrolyte interphase (SEI). The SEIs formed with traditional liquid electrolytes are heterogeneous and easy to crack during cycling, thus resulting in the formation of dendritic and dead Li, and further devastating the electrode performance. To solve these issues, efforts have been made to replace natural SEIs with artificial SEIs (ASEIs). Here, we discuss critical design principles of ASEIs based on the understanding of SEI failure mechanisms. Three key principles for a successful ASEI are identified: (1) mechanical stability, which can be either high strength or adaptivity, (2) spatially uniform Li+ transport with moderate conductivity and even single-ion conduction, and (3) chemical passivation to mitigate Li-electrolyte parasitic reactions. Selected examples of recently developed ASEIs are categorized and elaborated. Finally, future directions are given for ASEI designs.
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Global energy demands drive both academic and industrial interest in lithium-metal batteries, demanding the development of a stable artificial solid electrolyte interphase to protect the lithium-metal anode. Three critical design principles and selected examples of artificial solid electrolyte interphases are explored in this review.
There is an increasing demand for specialized pressure sensors in various applications. Previously, capacitive pressure sensors have been shown to have wide versatility in use, with a high degree of ...potential tuning possible through manipulating the geometry or material selection of the dielectric layer. However, in order to make sensors that are tunable and predictable, the design and fabrication method first needs to be developed. Presented here is an improved fabrication method to achieve tunable, consistent, and reproducible pressure sensors by using a pyramid microstructured dielectric layer along with a lamination layer. The as‐produced sensor performance is able to match predicted trends. Further, a simple model based on this system is developed and its efficacy is experimentally confirmed. Then, the model to predict a wide range of material and microstructure geometric properties prior to device fabrication is used to provide trends on sensor performance. Finally, it is demonstrated that the new method can be used to targetedly design a pressure sensor for a specific application—in vitro pulse sensing.
Tunable pressure sensors are achievable by geometric manipulation or material selection. To achieve this, tunable and reproducible pressure sensors are fabricated and modeled using a simple model based on microstructure properties. The model can be used to predict the effects of a wide range of material properties on sensor performance. Using this, targeted sensors for specific applications can be achieved.
The past couple of years have witnessed a remarkable burst in the development of organic field-effect transistors (OFETs), with a number of organic semiconductors surpassing the benchmark mobility of ...10 cm(2)/(V s). In this perspective, we highlight some of the major milestones along the way to provide a historical view of OFET development, introduce the integrated molecular design concepts and process engineering approaches that lead to the current success, and identify the challenges ahead to make OFETs applicable in real applications.
The exciting development of advanced nanostructured materials has driven the rapid growth of research in the field of electrochemical energy storage (EES) systems which are critical to a variety of ...applications ranging from portable consumer electronics, hybrid electric vehicles, to large industrial scale power and energy management. Owing to their capability to deliver high power performance and extremely long cycle life, electrochemical capacitors (ECs), one of the key EES systems, have attracted increasing attention in the recent years since they can complement or even replace batteries in the energy storage field, especially when high power delivery or uptake is needed. This review article describes the most recent progress in the development of nanostructured electrode materials for EC technology, with a particular focus on hybrid nanostructured materials that combine carbon based materials with pseudocapacitive metal oxides or conducting polymers for achieving high-performance ECs. This review starts with an overview of EES technologies and the comparison between various EES systems, followed by a brief description of energy storage mechanisms for different types of EC materials. This review emphasizes the exciting development of both hybrid nanomaterials and novel support structures for effective electrochemical utilization and high mass loading of active electrode materials, both of which have brought the energy density of ECs closer to that of batteries while still maintaining their characteristic high power density. Last, future research directions and the remaining challenges toward the rational design and synthesis of hybrid nanostructured electrode materials for next-generation ECs are discussed.
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► We review recent progress on hybrid nanostructured electrodes for electrochemical capacitors. ► We focus on hybrid electrodes combining carbon materials with metal oxides or conducting polymers. ► We emphasize novel porous structures for high loading of electroactive nanomaterials.
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