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Journal ArticleDOI: 10.1039/D0TA11508H

Polymerizable deep eutectic solvent-based mechanically strong and ultra-stretchable conductive elastomers for detecting human motions

02 Mar 2021-Journal of Materials Chemistry (The Royal Society of Chemistry)-Vol. 9, Iss: 8, pp 4890-4897
Abstract: Conductive elastomers (CEs) with strong mechanical properties have been fabricated and used in flexible electronics. However, the development of CEs with both super-high mechanical strength and extreme stretchability remains challenging. This paper reports on the development of a series of mechanically strong and tough CEs based on photopolymerizable deep eutectic solvents (PDESs) with dense hydrogen bonding interactions. One of these CEs exhibits the highest reported mechanical performance for elastomers, with tensile strength, strain at break and toughness up to 31.21 MPa, 3645% and 615 MJ m−3, respectively. Notably, this CE tolerates puncture and can lift a 10.5 kg weight (9500 times its own weight) without any failure. In addition, the series of CEs also shows excellent transparency (>94% in the visible range), favorable conductivity (0.007–0.04 S m−1), tunable stretchability (strain from 22% to 6164%) and good self-healing capability (electrical healing efficiency of 99% within 0.26 s). In view of the comprehensive properties of the CEs, we demonstrate the practical suitability of CEs by including them in a strain sensor to detect human motion. Based on their extremely facile preparation process and practical functionalities, we believe that CEs will not only contribute new methods for the development of mechanically strong conductors, but also open up novel avenues for flexible electronics.

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8 results found


Journal ArticleDOI: 10.1016/J.COMPOSITESB.2021.108984
Zixuan Zhou1, Zhirui He1, Shiwu Yin2, Xiaoyun Xie1  +1 moreInstitutions (2)
Abstract: Conductive, flexible and stretchable hydrogel sensors have attracted a lot of interest in human-machine interfaces, medical monitoring, and soft robotics. However, there are still have great challenges in the preparation of conductive hydrogels with self-adhesive, self-power and antibacterial properties. In order to meet the requirements of high sensitivity, convenient carrying and anti-allergic, so as to overcome the problems of traditional sensors, such as non-stickiness, absolute dependence on external power supply and skin irritation, the prepared poly(vinylalcohol)/poly(acrylamide-co-[2-(methacryloyloxy) ethyl] dimethyl-(3-sulfo-propyl) ammonium hydroxide) (PVA/P(AM-co-SBMA), PPS) hydrogel was obtained by UV crosslinking and freeze-thaw cycles. The PPS hydrogel has good mechanical properties (the elongation was 700% and the breaking strength was 370 kPa), high adhesion to various substrates, antibacterial properties (~99%) and wide sensory sensitivity. And the self-power sensor can be achieved by using hydrogel as the conductive medium to assemble primary battery with zinc foil and copper foil, the open circuit voltage of this self-powered system can reach 0.86 V. Furthermore, the assembled strain sensor can also convert chemical energy into electrical energy, and transform the resistance changes caused by stretching or compression into voltage signals for output. It can be used as effective wearable power supply for human motion detection. This kind of self-adhesive and antibacterial self-powered strain sensor was expected to play a great role in flexible bioelectronics.

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Topics: Self-healing hydrogels (55%), Bioelectronics (51%)

11 Citations


Journal ArticleDOI: 10.1016/J.MATT.2021.05.009
07 Jul 2021-
Abstract: Summary This Perspective underscores the use of deep eutectic systems (DESs) as efficient liquid active ingredients (including fully bio-based) and reaction media for biomass exploitation, valorization, and transformation into all-natural functional materials in a nonaqueous environment generally. Specifically, we discuss their employment as reaction media and final component of conductive flexible devices, nonaqueous eutectogels, and self-healing materials. Discussing a brief road map, we also highlight the opportunities that DESs offer for the creation of the next generation of bio-based and biodegradable flexible materials for soft robotics, wearable and implantable devices, artificial skin, edible materials, remote sensing, and substrates for photo- and electrochromic, (mechano)plasmonics, photonic and tribological devices. Taking advantage of their outstanding properties, we envision the rise of transformative technologies within a sustainable framework by using DESs in the years ahead.

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2 Citations


Open accessJournal ArticleDOI: 10.1016/J.GCE.2021.06.001
06 Jun 2021-
Abstract: Deep eutectic solvents (DESs) have received widespread attention for their advantages of good electrical conductivity, stability, environmental friendliness, and easy preparation with a wide range of applications. However, it was not until recent years that DESs were used as gel electrolytes as environmentally friendly alternatives to ionic liquids (ILs). In this mini review, we first introduce the DESs related eutectogels (or ion gels), then introduce the types and applications of the gels, the opportunities and challenges of them are also summarized.

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2 Citations


Journal ArticleDOI: 10.1039/D1TA06724A
Kai Zhao1, Kaili Zhang1, Ren'ai Li2, Peisen Sang1  +2 moreInstitutions (3)
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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Topics: Ionic liquid (55%), Ionic conductivity (53%), Ionic bonding (51%)

1 Citations


Journal ArticleDOI: 10.1016/J.COMPSCITECH.2021.109110
Ruofei Hu1, Guochen Ji1, Jing Zhao, Xiangling Gu  +2 moreInstitutions (1)
Abstract: Gel with satisfactory mechanical performance and reliability have received tremendous attention for their application. In this study, an elaborately designed dual cross-linked polyacrylamide/chitosan (PAM/CS) composite gel containing hydrogen bonds and coordination bonds was prepared by introducing phytic acid and cobalt ions into gel. During the preparation process, the oxidative polymerization and free water evaporation proceed simultaneously to obtain the gel by a water bath heating process. The PAM/CS gels possess excellent stretchability (∼3630%), self-adhesiveness, self-healing properties as well as self-extinguishing. Notably, the gel (PAM/CS-II) remains high strain after being placed for one month (0.22 MPa, 1022%) and even after heating or under the cold environment, demonstrating a long-term stability at room temperature and an extraordinary flexibility under a wide temperature spectrum. Extraordinary comprehensive properties can offer substantial benefit to their application, life span and security. PAM/CS-II gel can be directly employed as a strain sensor to evaluate the human motions, such as the subtle motion of the face and laryngeal knot. The human motions had been accurately detected with short response time by the strain sensor. This study strongly contributes to the strategy for the preparation and application for gel.

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Topics: Polyacrylamide (52%)

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53 results found


Open accessJournal ArticleDOI: 10.1126/SCIENCE.1240228
30 Aug 2013-Science
Abstract: Existing stretchable, transparent conductors are mostly electronic conductors. They limit the performance of interconnects, sensors, and actuators as components of stretchable electronics and soft machines. We describe a class of devices enabled by ionic conductors that are highly stretchable, fully transparent to light of all colors, and capable of operation at frequencies beyond 10 kilohertz and voltages above 10 kilovolts. We demonstrate a transparent actuator that can generate large strains and a transparent loudspeaker that produces sound over the entire audible range. The electromechanical transduction is achieved without electrochemical reaction. The ionic conductors have higher resistivity than many electronic conductors; however, when large stretchability and high transmittance are required, the ionic conductors have lower sheet resistance than all existing electronic conductors.

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Topics: Stretchable electronics (68%)

1,059 Citations


Journal ArticleDOI: 10.1021/SC500096J
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...

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Topics: Ionic liquid (51%)

1,024 Citations


Journal ArticleDOI: 10.1002/ADMA.201304742
Chaoyi Yan1, Jiangxin Wang1, Wenbin Kang1, Mengqi Cui1  +4 moreInstitutions (1)
01 Apr 2014-Advanced Materials
Abstract: Highly stretchable graphene-nanocellulose composite nanopaper is fabricated for strain-sensor applications. Three-dimensional macroporous nanopaper from crumpled graphene and nanocellulose is embedded in elastomer matrix to achieve stretchability up to 100%. The stretchable graphene nanopaper is demonstrated for efficient human-motion detection applications.

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Topics: Stretchable electronics (64%)

829 Citations


Journal ArticleDOI: 10.1021/JA045155B
Abstract: To realize polymer electrolytes with high ionic conductivity, we exploited the high ionic conductivity of an ionic liquid. In situ free radical polymerization of compatible vinyl monomers in a room temperature ionic liquid, 1-ethyl-3-methyl imidazolium bis(trifluoromethane sulfonyl)imide (EMITFSI), afforded a novel series of polymer electrolytes. Polymer gels obtained by the polymerization of methyl methacrylate (MMA) in EMITFSI in the presence of a small amount of a cross-linker gave self-standing, flexible, and transparent films. The glass transition temperatures of the gels, which we named "ion gels", decreased with increasing mole fraction of EMITFSI and behaved as a completely compatible binary system of poly(methyl methacrylate) (PMMA) and EMITFSI. The temperature dependence of the ionic conductivity of the ion gels followed the Vogel-Tamman-Fulcher (VTF) equation, and the ionic conductivity at ambient temperature reached a value close to 10(-2) S cm(-1). Similarly to the behavior of the ionic liquid, the cation in the ion gels diffused faster than the anion. The number of carrier ions, calculated from the Nernst-Einstein equation, was found to increase for an ion gel from the corresponding value for the ionic liquid itself. The cation transference number increased with decreasing EMITFSI concentration due to interaction between the PMMA matrix and the TFSI(-) anion, which prohibited the formation of ion clusters or associates, as was the case for the ionic liquid itself.

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Topics: Ionic liquid (63%), Ionic conductivity (60%), Radical polymerization (55%) ... show more

803 Citations


Journal ArticleDOI: 10.1038/NCHEM.2492
Cheng-Hui Li1, Chao Wang2, Chao Wang1, Christoph Keplinger3  +9 moreInstitutions (4)
01 Jun 2016-Nature Chemistry
Abstract: It is a challenge to synthesize materials that possess the properties of biological muscles-strong, elastic and capable of self-healing. Herein we report a network of poly(dimethylsiloxane) polymer chains crosslinked by coordination complexes that combines high stretchability, high dielectric strength, autonomous self-healing and mechanical actuation. The healing process can take place at a temperature as low as -20 °C and is not significantly affected by surface ageing and moisture. The crosslinking complexes used consist of 2,6-pyridinedicarboxamide ligands that coordinate to Fe(III) centres through three different interactions: a strong pyridyl-iron one, and two weaker carboxamido-iron ones through both the nitrogen and oxygen atoms of the carboxamide groups. As a result, the iron-ligand bonds can readily break and re-form while the iron centres still remain attached to the ligands through the stronger interaction with the pyridyl ring, which enables reversible unfolding and refolding of the chains. We hypothesize that this behaviour supports the high stretchability and self-healing capability of the material.

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Topics: Supramolecular polymers (50%)

798 Citations