A very mechanically strong and stretchable liquid-free double-network ionic conductor
26 Oct 2021-Journal of Materials Chemistry (The Royal Society of Chemistry)-Vol. 9, Iss: 41, pp 23714-23721
TL;DR: In this article, a series of very mechanically strong and tough liquid-free double-network ionic conductors (LFDNICs) are reported, consisting entirely of 1st stretchable poly(AA-ChCl) type supramolecular deep eutectic polymer networks and 2nd brittle polyvinylpyrrolidone (PVP) networks.
Abstract: Liquid-free ionic conductors are very desirable for flexible electronics, because hydrogels and ionic liquid-based ionogels suffer from water evaporation and ionic liquid leakage, respectively. However, the development of liquid-free ionic conductors with both high mechanical strength and stretchability remains challenging. In this work, based on the design concept of a double-network, we first report a series of very mechanically strong and tough liquid-free double-network ionic conductors (LFDNICs), consisting entirely of 1st stretchable poly(AA–ChCl) type supramolecular deep eutectic polymer networks and 2nd brittle polyvinylpyrrolidone (PVP) networks. One of these LFDNICs shows outstanding mechanical performance, with tensile strength, strain at break, and toughness up to 71.3 MPa, 671%, and 268 MJ m−3, respectively. In particular, the LFDNIC can endure puncture and successfully elevate a 10 kg weight (12 500 times its own weight). In addition, the LFDNIC also exhibits promising ionic conductivity (3.1 × 10−4 S m−1), favorable biocompatibility (cell viability up to 97.5%), optimum self-healing properties (electrical healing efficiency of 98% within 0.30 s), and adequate transparency (92% in the visible range). Due to their practical features and exceedingly simple preparation process, we believe that LFDNICs will not only provide an innovative prospect for the development of mechanically-strong ionic conductors, but can also be further researched and used in the fields of advanced sensors and flexible electronic devices.
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TL;DR: In this article , flexible sensors which can transduce various stimuli (e.g., strain, pressure, temperature) into electrical signals are highly in demand due to the development of human-machine interaction.
Abstract: Flexible sensors which can transduce various stimuli (e.g., strain, pressure, temperature) into electrical signals are highly in demand due to the development of human-machine interaction. However, it is still a...
23 citations
TL;DR: In this paper , a comprehensive review of stretchable ionic conductors is presented, in terms of their design, fabrication, properties, and applications, and the advantages and limitations of different types of stretchability.
Abstract: With the rapid development of soft electronics in the era of Internet of Everything (IoE), electrical conductors with stretchability, the indispensable components of soft electronics, have gained new opportunities and also faced increasing challenges. According to the principles of electrical conductivity, stretchable electrical conductors can be divided into electronic conductors and ionic conductors. Different from the stretchable electronic conductors derived from stretchable polymeric matrices integrated with electronically conductive fillers, stretchable ionic conductors are constructed by embedding mobile ions into the crosslinked polymer networks. Therefore, stretchable ionic conductors have received extensive attention and in-depth research in the past decade, thanks to their intrinsic stretchability and electrical conductivity. This review systematically summarizes the achievements on the different categories of stretchable ionic conductors (e.g., hydrogels, ionogels, and liquid-free ion-conductive elastomers), in terms of their design, fabrication, properties, and applications. The advantages and limitations of the different types of stretchable ionic conductors are discussed. Outlooks are also provided to envision the remaining challenges for the further development and practical applications of stretchable ionic conductors. It is expected to arouse inspirations for the design and fabrication of new and high-performance stretchable ionic conductors and advanced soft electronics for the IoE era. This article is protected by copyright. All rights reserved.
8 citations
TL;DR: In this article , a detachable poly(acrylic acid)-deep eutectic solvent (PAA-DES) was used to develop superstrong adhesives that can be detached via an environmental friendly trigger under mild operation conditions.
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TL;DR: Li et al. as discussed by the authors designed a series of repeatable self-adhesive liquid-free double-network ionic conductors (SALFDNICs), consisting of stretchable first poly(AA-ChCl)-type supramolecular deep eutectic polymer networks and stiff second polydopamine (PDA) networks.
Abstract: Liquid-free ionic conductors (LFICs) have promising applications in flexible electronics because most ionic conductors currently suffer from ionic liquid leakage or water evaporation issues. However, it has been a formidable challenge for LFICs to achieve long-term repeated self-adhesion on different substrates, especially on soft biological tissues. Based on the double-network design concept, we first fabricate a series of repeatable self-adhesive liquid-free double-network ionic conductors (SALFDNICs), consisting of stretchable first poly(AA-ChCl)-type supramolecular deep eutectic polymer networks and stiff second polydopamine (PDA) networks, which can maintain sufficient dynamic hydrogen bonds and catechol groups in the ionic conductors by preventing the overoxidation of dopamine, thus balancing the contradiction between adhesion and cohesion in liquid-free ionic conductors. Therefore, SALFDNICs can instantly form various interface interaction forces with multiple substrates (adhesion strength up to 757 N/m) and firmly adhere to various substrates for 20 detachment-reattachment cycles with a reduction in adhesion strength of less than 15%. Furthermore, SALFDNICs also have other comprehensive properties, such as optimum self-healing properties (self-healing efficiency of 90%), good stretchability (strain at break of 1200%), and promising conductivity (2.31 × 10-2 S m-1). Therefore, we believe that the extraordinary performance of SALFDNICs is important for improving device integration and the further development of flexible electronics.
6 citations
TL;DR: In this article , a solid-state conductive ionogels (SCIg) composed of long-chain copolymer networks without any volatile liquids were designed and prepared.
5 citations
References
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3,307 citations
TL;DR: Deep Eutectic Solvents (DES) as discussed by the authors are a class of solvents that can be defined as a mixture of two or more components, which at a particular composition present a high melting point depression becoming liquids at room temperature.
Abstract: Green technology actively seeks new solvents to replace common organic solvents that present inherent toxicity and have high volatility, leading to evaporation of volatile organic compounds to the atmosphere. Over the past two decades, ionic liquids (ILs) have gained enormous attention from the scientific community, and the number of reported articles in the literature has grown exponentially. Nevertheless, IL “greenness” is often challenged, mainly due to their poor biodegradability, biocompatibility, and sustainability. An alternative to ILs are deep eutectic solvents (DES). Deep eutectic solvents are defined as a mixture of two or more components, which may be solid or liquid and that at a particular composition present a high melting point depression becoming liquids at room temperature. When the compounds that constitute the DES are primary metabolites, namely, aminoacids, organic acids, sugars, or choline derivatives, the DES are so called natural deep eutectic solvents (NADES). NADES fully represen...
1,439 citations
TL;DR: The use of liquid metals based on gallium for soft and stretchable electronics is discussed, and these metals can be used actively to form memory devices, sensors, and diodes that are completely built from soft materials.
Abstract: The use of liquid metals based on gallium for soft and stretchable electronics is discussed. This emerging class of electronics is motivated, in part, by the new opportunities that arise from devices that have mechanical properties similar to those encountered in the human experience, such as skin, tissue, textiles, and clothing. These types of electronics (e.g., wearable or implantable electronics, sensors for soft robotics, e-skin) must operate during deformation. Liquid metals are compelling materials for these applications because, in principle, they are infinitely deformable while retaining metallic conductivity. Liquid metals have been used for stretchable wires and interconnects, reconfigurable antennas, soft sensors, self-healing circuits, and conformal electrodes. In contrast to Hg, liquid metals based on gallium have low toxicity and essentially no vapor pressure and are therefore considered safe to handle. Whereas most liquids bead up to minimize surface energy, the presence of a surface oxide on these metals makes it possible to pattern them into useful shapes using a variety of techniques, including fluidic injection and 3D printing. In addition to forming excellent conductors, these metals can be used actively to form memory devices, sensors, and diodes that are completely built from soft materials. The properties of these materials, their applications within soft and stretchable electronics, and future opportunities and challenges are considered.
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TL;DR: An ionic touch panel based on a polyacrylamide hydrogel containing lithium chloride salts is demonstrated, which can be operated under more than 1000% areal strain without sacrificing its functionalities.
Abstract: Because human-computer interactions are increasingly important, touch panels may require stretchability and biocompatibility in order to allow integration with the human body. However, most touch panels have been developed based on stiff and brittle electrodes. We demonstrate an ionic touch panel based on a polyacrylamide hydrogel containing lithium chloride salts. The panel is soft and stretchable, so it can sustain a large deformation. The panel can freely transmit light information because the hydrogel is transparent, with 98% transmittance for visible light. A surface-capacitive touch system was adopted to sense a touched position. The panel can be operated under more than 1000% areal strain without sacrificing its functionalities. Epidermal touch panel use on skin was demonstrated by writing words, playing a piano, and playing games.
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TL;DR: In this paper, a binary networked conductive hydrogel is prepared using acrylamide and polyvinyl alcohol, and an ultrastretchable pressure sensor with biocompatibility and transparency is fabricated cost effectively.
Abstract: In this study, a binary networked conductive hydrogel is prepared using acrylamide and polyvinyl alcohol. Based on the obtained hydrogel, an ultrastretchable pressure sensor with biocompatibility and transparency is fabricated cost effectively. The hydrogel exhibits impressive stretchability (>500%) and superior transparency (>90%). Furthermore, the self-patterned microarchitecture on the hydrogel surface is beneficial to achieve high sensitivity (0.05 kPa−1 for 0–3.27 kPa). The hydrogel-based pressure sensor can precisely monitor dynamic pressures (3.33, 5.02, and 6.67 kPa) with frequencydependent behavior. It also shows fast response (150 ms), durable stability (500 dynamic cycles), and negligible current variation (6%). Moreover, the sensor can instantly detect both tiny (phonation, airflowing, and saliva swallowing) and robust (finger and limb motions) physiological activities. This work presents insights into preparing multifunctional hydrogels for mechanosensory electronics.
394 citations