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Ion conduction of the PrDA fibers for use as bioelectrodes. a–c) Photos showing three copper electrodes were adhered by textiles knitted by PrDA fibers (a), the low (b) and high (c) magnification of the P(VSA‐co‐DMAPAA) textile attaching to the copper electrode. d) Ion conductivity and the corresponding resistivity of the P(VSA‐co‐DMAPAA), P(VPA‐co‐DMAPAA), and P(AA‐co‐DMAPAA) fibers. e) Ion conductivity and the corresponding resistivity of P(VSA‐co‐DMAPAA) fiber as a function of the concentration of LiCl. f) The percent resistance change (ΔR/R0) of the P(VSA‐co‐DMAPAA), P(VPA‐co‐DMAPAA), and P(AA‐co‐DMAPAA) fibers as a function of strain. g–i) EMG by cyclically working on a gripper at different working force (g), EMG by working on a gripper as a function of distance between the electrodes (h), EOG of a person during eye closing and eye opening (i), and ECG j) of a person by employing P(VSA‐co‐DMAPAA) textile electrodes. The insets show optical images of clasping a gripper (g), and eye opening and eye closing (i). The fiber diameter was 50 µm. The fibers contain LiCl (25%, w/w).
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Neurons exhibit excellent signal transmission capacity, which inspire artificial neuron materials for applications in the field of wearable electronics and soft robotics. In addition, the neuron fibers exhibit good mechanical robustness by sticking to the organs, which currently has rarely been studied. Here, a sticky artificial spider silk was dev...
Citations
... Hydrogel fibers are of interest in flexible electronics for their stretchability, ionic conductive pathway, and the ability to construct three-dimensional structures from the bottom up [1][2][3][4][5][6] . However, the high water content of hydrogel-based materials weakens their intraand intermolecular chain interactions, leading to poor mechanical properties of hydrogel-based materials [7][8][9][10] . ...
... Therefore, S-PAZr hydrogel fibers exhibited an overall improvement in tensile stress, tensile strain, elastic modulus, and toughness with increasing Na 2 SO 4 concentration. Taken together, the mechanical properties of S-PAZr hydrogel fibers could be easily customized over a broad range, including tensile stress from 8 3 . In addition, we visually compared the mechanical properties of S-PAZr hydrogel fibers with other reported hydrogel fibers and common high-toughness materials ( Fig. 3f-h). ...
Ideal hydrogel fibers with high toughness and environmental tolerance are indispensable for their long-term application in flexible electronics as actuating and sensing elements. However, current hydrogel fibers exhibit poor mechanical properties and environmental instability due to their intrinsically weak molecular (chain) interactions. Inspired by the multilevel adjustment of spider silk network structure by ions, bionic hydrogel fibers with elaborated ionic crosslinking and crystalline domains are constructed. Bionic hydrogel fibers show a toughness of 162.25 ± 21.99 megajoules per cubic meter, comparable to that of spider silks. The demonstrated bionic structural engineering strategy can be generalized to other polymers and inorganic salts for fabricating hydrogel fibers with broadly tunable mechanical properties. In addition, the introduction of inorganic salt/glycerol/water ternary solvent during constructing bionic structures endows hydrogel fibers with anti-freezing, water retention, and self-regeneration properties. This work provides ideas to fabricate hydrogel fibers with high mechanical properties and stability for flexible electronics.
... The neural network, a topological structure, orchestrates the regulation of organs and systems within the body by signal transmission, [40] with numerous dendrites and axons interlinked for this purpose. Additionally, neural networks possess inherent elasticity and mechanical robustness owing to special modifications in cytoskeletal composition that confer exceptional toughness to the long axons of the neurons (Figure 1a). ...
Concurrently achieving mechanical robustness, low hysteresis, and high transparency are essential for ionogels to enhance their reliability and satisfy the requirements in soft electronics. Fabricating ionogels comprising these characteristics presents a considerable challenge. Herein, inspired by the structure of neural networks, a new strategy for in situ formation of dense urea moieties aggregated domains is proposed to achieve topology‐tailoring polyurea ionogels. Initially, leveraging the pronounced disparity in reactivity of the isocyanate (─NCO) groups between isophorone diisocyanate (IPDI) and NCO‐terminated prepolymer (PPGTD), IPDI preferentially reacts with deblocked trifunctional latent curing agents, resulting in the formation of dense urea moieties aggregated domains. Thereafter, these domains are interconnected via PPGTD to establish polymer networks in which the ionic liquid is uniformly dispersed, forming neural networks like ionogels. Attributed to this unique design strategy, the polyurea ionogel demonstrates remarkable properties, including high strength (0.6–2.4 MPa), excellent toughness (0.9–4.3 MJ m⁻³), low hysteresis (6.6–11.6%), high transparency (>92%), along with enhanced fatigue and puncture resistance. Furthermore, the polyurea ionogels exhibit outstanding versatility, enabling their applications in strain sensors, flexible electroluminescence devices, and nanogenerators. This strategy contributes to the design of ionogels with unparalleled combinatory properties, catering to the diverse demands of soft ionotronic.
... The development of such materials is essential for modern industries that require materials that are both mechanically robust and environmentally resistant, in addition to being optically transparent. There are numerous applications for flexible transparent materials, ranging from biomedical [14,15] and environmental engineering [16][17][18] to the development of flexible sensors [19,20] and electrochemical [21][22][23] components. However, their development has been hindered by weak mechanical properties, low breathability, and high costs. ...
Nanofiber membranes (NFMs) have become attractive candidates for next-generation flexible transparent materials due to their exceptional flexibility and breathability. However, improving the transmittance of NFMs is a great challenge due to the enormous reflection and incredibly poor transmission generated by the nanofiber-air interface. In this research, we report a general strategy for the preparation of flexible temperature-responsive transparent (TRT) membranes, which achieves a rapid transformation of NFMs from opaque to highly transparent under a narrow temperature window. In this process, the phase change material eicosane is coated on the surface of the polyurethane nanofibers by electrospray technology. When the temperature rises to 37 °C, eicosane rapidly completes the phase transition and establishes the light transmission path between the nanofibers, preventing light loss from reflection at the nanofiber-air interface. The resulting TRT membrane exhibits high transmittance (> 90%), and fast response (5 s). This study achieves the first TRT transition of NFMs, offering a general strategy for building highly transparent nanofiber materials, shaping the future of next-generation intelligent temperature monitoring, anti-counterfeiting measures, and other high-performance devices.
Spider silk, possessing exceptional combination properties, is classified as a bio‐gel fiber. Thereby, it serves as a valuable origin of inspiration for the advancement of various artificial gel fiber materials with distinct functionalities. Gel fibers exhibit promising potential for utilization in diverse fields, including smart textiles, artificial muscle, tissue engineering, and strain sensing. However, there are still numerous challenges in improving the performance and functionalizing applications of spider silk‐inspired artificial gel fibers. Thus, to gain a penetrating insight into bioinspired artificial gel fibers, this review provided a comprehensive overview encompassing three key aspects: the fundamental design concepts and implementing strategies of gel fibers, the properties and strengthening strategies of gel fibers, and the functionalities and application prospects of gel fibers. In particular, multiple strengthening and toughening mechanisms were introduced at micro, nano, and molecular‐level structures of gel fibers. Additionally, the existing challenges of gel fibers are summarized. This review aims to offer significant guidance for the development and application of artificial gel fibers and inspire further research in the field of high‐performance gel fibers.
Spider silk exhibits an excellent combination of high strength and toughness, which originates from the hierarchical self-assembled structure of spidroin during fiber spinning. In this work, superfine nanofibrils are established in polyelectrolyte artificial spider silk by optimizing the flexibility of polymer chains, which exhibits combination of breaking strength and toughness ranging from 1.83 GPa and 238 MJ m⁻³ to 0.53 GPa and 700 MJ m⁻³, respectively. This is achieved by introducing ions to control the dissociation of polymer chains and evaporation-induced self-assembly under external stress. In addition, the artificial spider silk possesses thermally-driven supercontraction ability. This work provides inspiration for the design of high-performance fiber materials.
Neurofeedback training based on brain rhythm is appealing for both cognitive neuroscience and disorder treatment. However, electrodes that can integrate dual functions of recording and feedback without signal compromise still lack. Herein, an anisotropic cellulose carbon sponge (CCS) electrode by tailoring conductivity through the temperature that has the dual ability to record electrophysiological signals and sense pressures as feedback is developed. The electrode is fabricated via a gradient temperature annealing on CCS, which involves lower (300 °C) and higher (1000 °C) temperature treatments, namely CCS‐LT and CCS‐HT. CCS‐LT exhibits perpendicular resilience to the alignment direction of CCS, and CCS‐HT possesses lower sheet resistance (≈13 Ω sq⁻¹) parallel to the alignment direction. As a pressure sensor, CCS‐LT can achieve excellent sensitivity (1.04 kPa⁻¹), fast response time (27 ms), and reliable stability for 1000 cycles. CCS‐HT can serve as skin electrodes for electrophysiological sensing. The anisotropic functionality of annealed CCS allows it to be used in one sensing and regulation closed‐loop system driven by nerves, achieving accurate acquisition of human brain rhythm and machine movement information simultaneously. This not only helps rapid tracking of brain activity but also facilitates feedback regulation to enhance human brain function, having great potential applications in neurofeedback and disease rehabilitation.
Nature has a remarkable ability to create multifunctional fibers, such as spider silk, by precisely controlling structures across various scales. However, replicating this in high‐speed spun synthetic fibers is challenging due to the absence of life‐specific forces and interactions required for manipulating composition, gradients, and structures. Here, a novel droplet‐coupled pultrusion spinning technique is demonstrated for industrial‐scale production of microfibers with hierarchical structures. Droplets spontaneously form on the surface of high‐speed spun fibers to tailor multiscale hierarchical structures, resulting in a nonlinear viscoelastic core embedded with anharmonic nanosprings consisting of amorphous and crystalline domains and a periodically reinforced nanofiber skin. These structural hierarchies enable unique mechanical property combinations including nonlinear viscoelasticity, large extensibility (613%), record‐high toughness (536 MJ m⁻³), highly efficient impact energy absorption, vibration damping and wide temperature adaptability (−67.4 to 278.9 °C). Additionally, the structured bioinspired fibers exhibit low‐frequency phononic bandgap and anomalous dispersion of mechanical waves. The droplet‐based approach allows precise control over heterogeneity at multiple scales within the identical components leading to impressive mechanical performance and additional functionalities, and is consider that it could be applied to the design of the next era of hierarchically structured nanocomposites for a wide range of applications.
