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1.
Stretchable ionic conductors such as hydrogels and ionic-liquid-based gels (aka ionogels) have garnered great attention as they enable the development of soft ionotronics. Notably, soft ionotronic devices inevitably operate in humid environments or under mechanical loads. However, many previously reported hydrogels and ionogels, however, are unstable in environments with varying humidity levels owing to hydrophilicity, and their liquid components (i.e., ionic liquid, water) may leak easily from polymer matrices under mechanical loads, causing deterioration of device performance. This work presents novel hydrophobic ionogels with strong ionic liquid retention capability. The ionogels are ambiently and mechanically stable, capable of not absorbing moisture in environments with high relative humidity and almost not losing liquid components during long periods of mechanical loading. Moreover, the ionogels exhibit desirable conductivity (10−4–10−5 S cm−1), large rupturing strain (>2000%), moderate fractocohesive length (0.511.03 mm), and wide working temperature range (−60 to 200 °C). An ionic skin is further designed by integrating the concept of sensory artificial skins and triboelectric nanogenerators, which can convert multiple stimuli into various types of signals, including resistance, capacitance, short-circuit current, and open-circuit voltage. This work may open new avenues for the development of soft ionotronics with stable performance.  相似文献   

2.
Harvesting low-grade waste heat from the natural environment with thermoelectric materials is considered as a promising solution for the sustainable energy supply for wearable electronic devices. For practical applications, it is desirable to endow the thermoelectric materials with excellent mechanical and self-healing properties, which remains a great challenge. Herein, the design and characterization of a series of high-performance ionic hydrogels for soft thermoelectric generator applications are reported. Composed of a physically cross-linked network of polyacrylic acid (PAA) and polyethylene glycol (PEO) doped with sodium chloride, the resulting PAA-PEO-NaCl ionic hydrogels demonstrates impressive mechanical strength (breaking stress >1.3 MPa), stretchability (>1100%), and toughness (up to 7.34 MJ m−3). Moreover, the reversible hydrogen bonding interaction and chain entanglement render the ionic hydrogels with excellent mechanical resilience, adhesion properties, and self-healing properties. At ambient conditions, the electrochemical and thermoelectric performance of the ionic hydrogels can be restored immediately from physical damage such as cutting, and the mechanical healing can be completely restored within 24 h. At the optimized composition, the Seebeck coefficient of the ionic hydrogels can reach 3.26 mV K−1 with a low thermal conductivity of 0.321 W m−1 K−1. Considering the excellent mechanical properties and thermoelectric performance, it is believed that the ionic hydrogels are widely applicable in ionic thermoelectric capacitors to convert low-grade heat into electricity for soft electronic devices.  相似文献   

3.
Emerging soft ionotronics better match the human body mechanically and electrically compared to conventional rigid electronics. They hold great potential for human-machine interfaces, wearable and implantable devices, and soft machines. Among various ionotronic devices, ionic junctions play critical roles in rectifying currents as electrical p–n junctions. Existing ionic junctions, however, are limited in electrical and mechanical performance, and are difficult to fabricate and degrade. Herein, the design, fabrication, and characterization of tough transient ionic junctions fabricated via 3D ionic microgel printing is reported. The 3D printing method demonstrates excellent printability and allows one to fabricate ionic junctions of various configurations with high fidelity. By combining ionic microgels, degradable networks, and highly charged biopolymers, the ionic junctions feature high stretchability (stretch limit 27), high fracture energy (>1000 Jm−2), excellent electrical performance (current rectification ratio >100), and transient stability (degrade in 1 week). A variety of ionotronic devices, including ionic diodes, ionic bipolar junction transistors, ionic full-wave rectifiers, and ionic touchpads are further demonstrated. This study merges ionotronics, 3D printing, and degradable hydrogels, and will motivate the future development of high-performance transient ionotronics.  相似文献   

4.
Novel liquid-free ionic conductive elastomers are fabricated by the polymerization of acrylic acid (AA) in polymerizable deep eutectic solvent (PDES). Liquid metal (LM) nanodroplets are used to initiate and further cross-link polyacrylic acid (PAA) chains into a liquid-free polymeric network without any extra initiators and cross-linkers. The resulting liquid-free ionic conductive elastomers exhibit high transparency (94.1%), ultra-stretchability (2600%), and autonomous self-healing. Spin trapping electron paramagnetic resonance and dye fading experiments reveal the generation of free radicals. UV–visible spectrometry and viscosity tests demonstrate the cross-linking effect of Ga3+. The gelation time is much shorter than that of the conventional ammonium persulfate thermal initiation process. Furthermore, this liquid-free polymer material is intrinsically resistant to freezing and drying, enabling it to operate under harsh conditions. In consideration of transparency, self-healing, ultra-stretchability, moldability, and sensory features, the resulting elastomeric conductor may hold promise for industrial applications in wearable devices, force mapping, and flexible electroluminescent devices.  相似文献   

5.
The development of ultralow voltage high-performance bioartificial muscles with large bending strain, fast response time, and excellent actuation durability is highly desirable for promising applications such as soft robotics, active biomedical devices, flexible haptic displays, and wearable electronics. Herein, a novel high-performance low-priced bioartificial muscle based on functional carboxylated bacterial cellulose (FCBC) and polypyrrole (PPy) nanoparticles is reported, exhibiting a large bending strain of 0.93%, long actuated bending durability (96% retention for 5 h) under an ultralow harmonic input of 0.5 V, broad frequency bandwidth up to 10 Hz, fast response time (≈4 s) in DC responses, high energy density (6.81 KJ m−3), and high power density (5.11 KW m−3), all of which mainly stem from its high surface area and porosity, large specific capacitance, tuned mechanical properties, and strong ionic interactions of cations and anions in ionic liquid with FCBC and PPy nanoparticles. More importantly, bioinspired applications such as the grapple robot, bionic medical stent, bionic flower, and wings-vibrating have been realized. These successful demonstrations offer a viable means for developing high-performance bioartificial muscles for next-generation soft bioelectronics including bioinspired robotics, biomedical microdevices, and wearable electronics.  相似文献   

6.
To realize wearable displays and interactive soft robots, significant research efforts are focused on developing highly deformable alternating-current electroluminescent (ACEL) devices. Although soft emission layers are well developed, designing stretchable, conductive, and transparent soft electrodes remains challenging. In this study, ionic hydrogels are prepared comprising a double network (DN) of poly(N-hydroxyethylacrylamide-co-acrylamide)/crosslinked chitosan swollen in aqueous lithium bis(trifluoromethanesulfonyl) imide. Owing to the finely tuned DN structure of the polymeric crosslinker and transparent electrolyte, the developed ionic hydrogels exhibit remarkable stretchability (1400%), excellent optical transmittance (>99%), and high conductivity (1.95 × 10−2 Sm−1). Based on the high performance of the ionic hydrogels, ACEL devices are fabricated with an emission layer containing phosphor microparticles and demonstrate stable, high luminance under extreme deformation, and ultra-high elongation. The excellent transparency of the ionic hydrogel further enables the fabrication of novel soft ACEL devices with tandem structures by stacking several emission and electrode layers, in which each emission layer is independently controlled with a switch circuit.  相似文献   

7.
Interest in wearable and stretchable on-skin motion sensors has grown rapidly in recent years. To expand their applicability, the sensing element must accurately detect external stimuli; however, weak adhesiveness of the sensor to a target object has been a major challenge in developing such practical and versatile devices. In this study, freestanding, stretchable, and self-adhesive ionogel conductors are demonstrated which are composed of an associating polymer network and ionic liquid that enable conformal contact between the sensor and skin even during dynamic movement. The network of ionogel is formed by noncovalent association of two diblock copolymers, where phase-separated micellar clusters are interconnected via hydrogen bonds between corona blocks. The resulting ionogels exhibit superior adhesive characteristics, including a very high lift-off force of 93.3 N m−1, as well as excellent elasticity (strain at break ≈ 720%), toughness ( ≈ 2479 kJ m−3), thermal stability ( ≈ 150  ° C), and high ionic conductivity ( ≈ 17.8 mS cm−1 at 150  ° C). These adhesive ionogels are successfully applied to stretchable on-skin strain sensors as sensing elements. The resulting devices accurately monitor the movement of body parts such as the wrist, finger, ankle, and neck while maintaining intimate contact with the skin, which was not previously possible with conventional non-adhesive ionogels.  相似文献   

8.
Stretchable conductors are indispensable building blocks for stretchable electronic devices that are used in next-generation wearable electronics, on-skin electronics, and soft robotics. Whereas, the ability to realize synergy high conductance and sufficient conductivity under high strain remains challenging. Herein, a stretchable conductor made from tightly assembled core–shell polydimethylsiloxane@silver microspheres (PDMS@Ag MPs) is elaborated. By judiciously using evaporation-induced capillary effect, 3D interconnected conductive paths consisting of closely packed conductive PDMS@Ag MPs are constructed inside the elastic matrix. The spatially selective distributed Ag-shell enables conductor metallic conductivity (67185 S cm−1) at ultralow Ag fraction (19.5 wt.%), and well-maintained conductance over wide strain (820 S cm−1 at 400%). Due to the suppressed Ag content, both the rapture strain and Young's modulus (613%, 0.79 MPa for CPSC4) of the conductor are largely retained. Besides, the synergy hierarchical surface topology and low surface energy endow conductors with high water-repellent properties. The fabricated conductors with remarkably high conductivity, well-retained conductance under large strain, and robust hydrophobicity are of great significance for advanced stretchable electronics.  相似文献   

9.
Coordination complexes are widely used to tune the mechanical behaviors of polymer materials, including tensile strength, stretchability, self-healing, and toughness. However, integrating multivalent functions into one material system via solely coordination complexes is challenging, even using combinations of metal ions and polymer ligands. Herein, a single-step process is described using silver-based coordination complexes as cross-linkers to enable high compressibility (>85%). The resultant organogel displays a high compressive strength (>1 MPa) with a low energy loss coefficient (<0.1 at 50% strain). Remarkably, it demonstrates an instant self-recovery at room temperature with a speed >1200 mm s−1, potentially being utilized for designing high-frequency-responsive soft materials (>100 Hz). Importantly, in situ silver nanoparticles are formed, effectively endowing the organogel with high conductivity (550 S cm−1). Given the synthetic simplification to achieve multi-valued properties in a single material system using metal-based coordination complexes, such organogels hold significant potential for wearable electronics, tissue-device interfaces, and soft robot applications.  相似文献   

10.
Soft and flexible conductors are essential for the development of soft robots, wearable electronics, electronic tissue, and implants. However, conventional soft conductors are inherently characterized by a large change in conductance upon mechanical deformation or under alternating environmental conditions, e.g., humidity, drastically limiting their application potential. This work demonstrates a novel concept for the development of strain-invariant, highly elastic and highly water stable all-organic soft conductors, overcoming the limitations of previous strain-invariant soft conductors. For the first time, thin film deposition technologies are combined in a three-dimensional fashion, resulting in micro- and nano-engineered, multi-layered (<50 nm), ultra-lightweight (< 15 mg cm3) foam-like framework structures based on Poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) and Polytetrafluoroethylene (PTFE), characterized by a highly strain-invariant conductivity (≈184 S/m) between 80% compressive and 25% tensile strain. Both the initial electrical and mechanical properties are retained during long-term cycling, even after 2000 cycles at 50% compression. Furthermore, the PTFE thin film renders the framework structure highly hydrophobic, resulting in stable electrical properties, even when immersed in water for a month. Such innovative multi-scaled and multi-layered functional materials are of interest for a broad range of applications in soft electronics, energy storage and conversion, sensing, water and air purification, as well as biomedicine.  相似文献   

11.
The primary technology of next‐generation wearable electronics pursues the development of highly deformable and stable systems. Here, nonvolatile, highly transparent, and ultrastretchable ionic conductors based on polymeric gelators [poly(methyl methacrylate‐ran‐butyl acrylate), PMMA‐r‐PBA] and ionic liquids (IL) are proposed. A crucial strategy in the molecular design of polymer gelators is copolymerization of PMMA and IL‐insoluble low glass transition temperature (Tg) polymers that can be deformed and effectively dissipate applied strains. Highly stretchable (elongation limit ≈850%), mechanically robust (elastic modulus ≈3.1 × 105 Pa), and deformation durable (recovery ratio ≈96.1% after 500 stretching/releasing cycles) gels are obtained by judiciously adjusting the molecular characteristics of polymer gelators and gel composition. An extremely simple “ionic” strain sensory platform is fabricated by directly connecting the stretchable gel and a digital multimeter, exhibiting high sensitivity (gauge factor ≈2.73), stable operation (>13 000 cycles), and nonvolatility (>10 d in air). Moreover, the skin‐type strain sensor, referred to as ionoskin, is demonstrated. The gels are attached to a part of the body (e.g., finger, elbow, knee, or ankle) and various human movements are successfully monitored. The ionoskin renders the opportunity to achieve wearable ubiquitous electronics such as healthcare devices and smart textile systems.  相似文献   

12.
Ionic conductors, such as hydrogels, ionogels, and eutectogels, have attained considerable research interest in various advanced application scenarios. However, such ionic conductors still suffer from the restriction of inherent liquid compositions, which may leak or evaporate. Herein, inspired by the control strategy of desertification caused by soil erosion, a novel internal-external dual enhancement design strategy, i.e., increasing the interaction between the filler itself and its matrix, is proposed to firmly embed the deep eutectic solvent (DES) into polyurethane (PU) to prevent liquid leakage, such that the prepared ionic conductive elastomers (PU-DESs) are quasi-solid. The PU-DESs exhibit marvelous versatility including high stretchability, tensile strength, toughness, self-healing efficiency, antibacterial ability, ionic conductivity, and excellent freezing tolerance. More intriguingly, benefiting from their quasi-solid feature, PU-DESs are endowed with long-term environmental stability. Thanks to these superb versatile features, PU-DESs are further successfully applied in the wearable sensor and triboelectric nanogenerator (TENG) for monitoring human motions and converting mechanical energy into electrical energy, breaking away from the limitations of previous most soft iontronics such as liquid leakage or evaporation and weak mechanical strength. Hence, this study establishes an effective material design strategy for various soft iontronics demanding environmental stability and durability.  相似文献   

13.
Ionic conducting eutectogels have attracted enormous attention as an alternative to the conventional temperature-intolerant hydrogels and costly ionic liquid gels in constructing flexible electronic devices. However, current eutectogels prepared via cross-linked polymer or low-molecular-weight gelators suffer from limited stretchability and insufficient surface-adaptive adhesion. Herein, a low-molecular-weight supramolecular network is introduced into a covalent polymer network in a eutectogel architecture, and a novel supramolecular-polymer double-network (SP-DN) strategy is demonstrated to fabricate conductive SP-DN eutectogels with high stretchability (>4000% elongation) and toughness (≈800 J m−2), as well as self-healing, self-adhesive and anti-freezing/anti-drying characteristics. These unique features lead to the successful realization of SP-DN eutectogels in wearable self-adhesive strain sensors, which can conformally deform with the skin and dynamically monitor body movements with high sensitivity and long-term stability over a wide temperature range (−40 to 60 °C). Furthermore, the strain sensors can accurately detect body movements along two opposite directions (bend up or bend down), which are rarely reported in the literature. Distinct from the widely explored polymer double-network (P-DN) hydrogels, the developed SP-DN eutectogel platform is capable of well-regulating molecular-scale noncovalent and covalent interactions, providing a paradigm for the creation of smart soft materials with versatile performance and high environmental adaptability.  相似文献   

14.
《Organic Electronics》2014,15(5):1056-1061
We report on flexible, single electrospun nanofiber field-effect transistors made by a blend of poly(3-decylthiophene) and poly(3-hexylthiophene), assessing for the first time the performances of this class of devices in terms of stability upon repeated tensile bending. Charge-carrier mobilities in the nanofiber-based device are estimated of the order of 10−3 cm2/(V s). Repeated cycles of bending and relaxing are performed, and the evolution of the device current–voltage characteristics is monitored up to 1000 cycles. We find that during bending the mobility is higher than that measured in planar conditions, and that after about 100 bending cycles it rapidly stabilizes. The here observed bending stability suggests a high compatibility of electrospun nanofibers with devices fabricated by roll-to-roll processes, and with bendable or wearable electronics.  相似文献   

15.
Inspired by nature, various self-healing materials that can recover their physical properties after external damage have been developed. Recently, self-healing materials have been widely used in electronic devices for improving durability and protecting the devices from failure during operation. Moreover, self-healing materials can integrate many other intriguing properties of biological systems, such as stretchability, mechanical toughness, adhesion, and structural coloration, providing additional fascinating experiences. All of these inspirations have attracted extensive research on bioinspired self-healing soft electronics. This review presents a detailed discussion on bioinspired self-healing soft electronics. Firstly, two main healing mechanisms are introduced. Then, four categories of self-healing materials in soft electronics, including insulators, semiconductors, electronic conductors, and ionic conductors, are reviewed, and their functions, working principles, and applications are summarized. Finally, human-inspired self-healing materials and animal-inspired self-healing materials as well as their applications, such as organic field-effect transistors (OFETs), pressure sensors, strain sensors, chemical sensors, triboelectric nanogenerators (TENGs), and soft actuators, are introduced. This cutting-edge and promising field is believed to stimulate more excellent cross-discipline works in material science, flexible electronics, and novel sensors, accelerating the development of applications in human motion monitoring, environmental sensing, information transmission, etc.  相似文献   

16.
Hydrogel electrolytes have high room-temperature conductivity and can be widely used in energy storage device. However, hydrogels suffer from the inevitable freezing of water at subzero temperatures, resulting in the diminishment of their conductivity and mechanical properties. How to achieve high conductivity without sacrificing hydrogels’ flexibility at subzero temperature is an important challenge. To address this challenge, a new type of zwitterionic polymer hydrogel (polySH) electrolytes is fabricated. The anionic and cationic counterions on the polymer chains facilitate the dissociation of LiCl. The antifreezing electrolyte can be stretched to a strain of 325% and compressed to 75% at −40 °C and possesses an outstanding conductivity of 12.6 mS cm−1 at −40 °C. A direct hopping migration mechanism of hydrated lithium-ion through the channel of zwitterion groups is proposed. The polySH electrolyte-based-supercapacitor (SC) exhibits a high specific capacitance of 178 mF cm−2 at 60 °C and 134 mF cm−2 at −30 °C with a retention of 81% and 71% of the initial capacitance after 10 000 cycles, respectively. The overall merits of the electrolyte will open up a new avenue for advanced ionic conductors and energy storage device in practical applications.  相似文献   

17.
Developing high-performance nanofluidic fibers with synergetic ionic and electric conductivities is promising for human–machine interface interaction. In such a scenario, inter- and intra-forces in constituent flakes are recognized as crucial factors in determining the derived nanofluidic fiber performance. In this work, the rheological properties of Ti3C2Tx MXene solution are systematically optimized by regulating the electrostatic interaction via introducing multivalent metal cations. As a result, such multivalent cations trigger ionic crosslinking and remarkably strengthen the interaction force between nanosheets, which even forms into a tight fiber-shaped gel network. A series of cations, such as K+, Na+, Mg2+, Zn2+, and Al3+, are introduced to enhance the ionic cross-linking between interconnected flakes. The thus-prepared Zn2+-Ti3C2Tx fiber exhibits a remarkable electrical conductivity of 11 200 S cm−1, a tensile strength of 252 MPa, and an ionic conductivity of 2.51 × 10−3 S cm−1. This multivalent cation crosslinking strategy could offer some insights into developing functional nanofluidic fibers for wearable or healthcare applications.  相似文献   

18.
Aqueous zinc-ion micro-batteries (ZIMBs) have attracted considerable attention owing to their reliable safety, low cost, and great potential for wearable devices. However, current ZIMBs still suffer from various critical issues, including short cycle life, poor mechanical stability, and inadequate energy density. Herein, the fabrication of flexible planar ZIMBs with ultrahigh energy density by interfacial engineering in the screen-printing process based on high-performance MnO2-based cathode materials is reported. The Ce-doped MnO2 (Ce-MnO2) exhibits significantly enhanced capacity (389.3 mAh g−1), considerable rate capability and admirable cycling stability than that of the pure MnO2. Importantly, the fabrication of micro-electrodes with ultrahigh mass loading of Ce-MnO2 (24.12 mg cm−2) and good mechanical stability is achieved through optimizing the interfacial bonding between different printed layers. The fabricated planar ZIMBs achieve a record high capacity (7.21 mAh cm−2 or 497.31 mAh cm−3) and energy density (8.43 mWh cm−2 or 573.45 mWh cm−3), as well as excellent flexibility. Besides, a wearable self-powered sensing system for environmental monitoring is further demonstrated by integrating the planar ZIMBs with flexible solar cells and a multifunctional sensor array. This work sheds light on the development of high-performance planar ZIMBs for future self-powered and eco-friendly smart wearable electronics.  相似文献   

19.
Known for its capability to architect tailored structures for the scaling of active materials in energy storage devices that cater for future electronics having stringent requirements on areal performance, 3D printing is receiving serious attention. However, lingering challenges originating from the notorious interfacial issue and weak component interaction restrain current devices from making a breakthrough in deliverable capacity and structural flexibility. In this work, the printed electrode delivers a record-breaking electrical double layer (EDL) areal capacitance of 27.1 F cm−2 under an extremely large loading density of 134 mg cm−2. This translates to a deliverable record-high EDL energy density of 1.26 mWh cm−2 for device performance, which even rivals the highest value reported from highly loaded pseudocapacitors. The bespoke devices are enabled by a strategically formulated 3D printable ink that initiates efficient autonomous room-temperature self-healing and strong interplay between constituting ink components. These contribute to interlayer coalescing for eliminated interlayer resistance for a solid electrochemical performance and printed electrodes of great mechanical compliance. By tapping into the huge potential of 3D printing, this work lays a solid foundation on which flexible devices with customized geometry, functionality, and outstanding performance for a broad range of applications can be readily realized.  相似文献   

20.
Soft robots are susceptible to premature failure from physical damages incurred within dynamic environments. To address this, we report an elastomer with high toughness, room temperature self-healing, and strong adhesiveness, allowing both prevention of damages and recovery for soft robotics. By functionalizing polyurethane with hierarchical hydrogen bonds from ureido-4[1H]-pyrimidinone (UPy) and carboxyl groups, high toughness (74.85 MJ m−3), tensile strength (9.44 MPa), and strain (2340%) can be achieved. Furthermore, solvent-assisted self-healing at room temperature enables retention of high toughness (41.74 MJ m−3), tensile strength (5.57 MPa), and strain (1865%) within only 12 h. The elastomer possesses a high dielectric constant (≈9) that favors its utilization as a self-healing dielectric elastomer actuator (DEA) for soft robotics. Displaying high area strains of ≈31.4% and ≈19.3% after mechanical and electrical self-healing, respectively, the best performing self-healable DEA is achieved. With abundant hydrogen bonds, high adhesive strength without additional curing or heating is also realized. Having both actuation and adhesive properties, a “stick-on” strategy for the assembly of robust soft robots is realized, allowing soft robotic components to be easily reassembled or replaced upon severe damage. This study highlights the potential of soft robots with extreme ruggedness for different operating conditions.  相似文献   

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