Jing Zhang

Nature, Published online: 21 August 2024; doi:10.1038/s41586-024-07826-x

An on-chip platform with in situ adjustable interfacial properties, using a microelectromechanical system, provides multi-degree-of-freedom control of two-dimensional materials, including twisting and pressurizing.

Nature, Published online: 21 August 2024; doi:10.1038/d41586-024-02634-9

Single crystals of atomically thin sapphire have been prepared at room temperature — something that many scientists thought was impossible. These materials could enable the development of the next generation of transistors for use in miniaturized chips.

The LaAlO₃/SrTiO₃ interface hosts a plethora of gate-tunable electronic phases. Here, quasi-1D ballistic electron waveguides are sketched at the LaAlO₃/SrTiO₃ interface as a probe to understand how gate tunability varies as a function of spatial separation. Gate tunability measurements reveal a non-Coulombic coupling at the interface in contrast to traditional semiconductor systems.

Abstract

The LaAlO₃/SrTiO₃ interface hosts a plethora of gate-tunable electronic phases. Gating of LaAlO₃/SrTiO₃ interfaces is usually assumed to occur electrostatically. However, increasing evidence suggests that non-local interactions can influence and, in some cases, dominate the coupling between applied gate voltages and electronic properties. Here, quasi-1D ballistic electron waveguides are sketched at the LaAlO₃/SrTiO₃ interface as a probe to understand how gate tunability varies as a function of spatial separation. Gate tunability measurements reveal the scaling law to be at odds with the pure electrostatic coupling observed in traditional semiconductor systems. The non-Coulombic gating at the interface is attributed to a long-range nanoelectromechanical coupling between the gate and electron waveguide, possibly mediated by the ferroelastic domains in SrTiO₃. The long-range interactions at the LaAlO₃/SrTiO₃ interface add unexpected richness and complexity to this correlated electron system.

Nature Communications, Published online: 21 August 2024; doi:10.1038/s41467-024-51516-1

The inherent porosity of auxetic metamaterials challenge their applicability. Here, the authors introduce a seamless auxetic substrate film capable of achieving a negative Poisson’s ratio of −1 incorporating a rigid auxetic structure reinforced by glass-fabric, with surface-flattening soft elastomers applied as an image distortion-free display.

Nature Chemistry, Published online: 20 August 2024; doi:10.1038/s41557-024-01604-y

The construction of synthetic cells holds great importance for exploring complex biological systems and could potentially provide insights into the origins of life. Now, synthetic gap junctional channels have been developed as a building block to construct synthetic cells that can mediate intercellular transport of ions and bioactive species.

Nature Electronics, Published online: 20 August 2024; doi:10.1038/s41928-024-01239-4

A probe that measures more neurons across the brain

3D printing – With peptides, for cells. Adding low amounts of cell-adhesive peptide to a polyethylene-glycol-based ink reverses its cell-adhesion properties. This ink can directly be used for two-photon laser printing thus avoiding cumbersome material post-functionalization. Precise microstructured designs can be printed and used for cell experiments. Various material designs are presented, including patterned cell-adhesive/cell-repellent multimaterials or materials with fluorescence-labelled peptides.

Abstract

Here, a straightforward method is reported for manufacturing 3D microstructured cell-adhesive and cell-repellent multimaterials using two-photon laser printing. Compared to existing strategies, this approach offers bottom-up molecular control, high customizability, and rapid and precise 3D fabrication. The printable cell-adhesive polyethylene glycol (PEG) based material includes an Arg-Gly-Asp (RGD) containing peptide synthesized through solid-phase peptide synthesis, allowing for precise control of the peptide design. Remarkably, minimal amounts of RGD peptide (< 0.1 wt%) suffice for imparting cell-adhesiveness, while maintaining identical mechanical properties in the 3D printed microstructures to those of the cell-repellent, PEG-based material. Fluorescent labeling of the RGD peptide facilitates visualization of its presence in cell-adhesive areas. To demonstrate the broad applicability of the system, the fabrication of cell-adhesive 2.5D and 3D structures is shown, fostering the adhesion of fibroblast cells within these architectures. Thus, this approach allows for the printing of high-resolution, true 3D structures suitable for diverse applications, including cellular studies in complex environments.

An effective strategy is developed to construct the transient anticounterfeiting hydrogels by M²⁺-carboxyl coordination complexes in PAA gels. M²⁺ can induce the transparent-to-turbid transition and the cold temperature of PAA gels can continuously vary with M²⁺ concentration. By leveraging the local diffusion of M²⁺ into a PAA gel, the transient display of encrypted information with temperature is realized.

Abstract

Hydrogels have emerged as promising candidates for anticounterfeiting materials, owing to their unique stimulus-responsive capabilities. To improve the security of encrypted information, efforts are devoted to constructing transient anticounterfeiting hydrogels with a dynamic information display. However, current studies to design such hydrogel materials inevitably include sophisticated chemistry, complex preparation processes, and particular experimental setups. Herein, a facile strategy is proposed to realize the transient anticounterfeiting by constructing bivalent metal (M²⁺)-coordination complexes in poly(acrylic acid) gels, where the cloud temperature (T _c) of the gels can be feasibly tuned by M²⁺ concentration. Therefore, the multi-T _c parts in the gel can be locally programmed by leveraging the spatially selective diffusion of M²⁺ with different concentrations. With the increase of temperature or the addition of a complexing agent, the transparency of the multi-T _c parts in the gel spontaneously evolves in natural light, enabling the transient information anticounterfeiting process. This work has provided a new strategy and mechanism to fabricate advanced anticounterfeiting hydrogel materials.

Inspired by water striders, an electricity-driven multifunctional swimming Marangoni robot is proposed, which is fabricated by super-aligned carbon nanotube and polyimide composites. The robot swims on the water surface based on the thermal Marangoni effect and can grasp objects using air-ambient actuators. The functions of swimming through tunnels, being charged on the water surface, and being driven by light are also demonstrated.

Abstract

Marangoni actuators that are propelled by surface tension gradients hold significant potential in small-scale swimming robots. Nevertheless, the release of “fuel” for conventional chemical Marangoni actuators is not easily controllable, and the single swimming function also limits application areas. Constructing controllable Marangoni robots with multifunctions is still a huge challenge. Herein, inspired by water striders, electricity-driven strategies are proposed for a multifunctional swimming Marangoni robot (MSMR), which is fabricated by super-aligned carbon nanotube (SACNT) and polyimide (PI) composite. The MSMR consists of a Marangoni actuator and air-ambient actuators. Owing to the temperature gradient generated by the electrical stimulation on the water surface, the Marangoni actuators can swim controllably with linear, turning, and rotary motions, mimicking the walking motion of water striders. In addition, the Marangoni actuators can also be driven by light. Importantly, the air-ambient actuators fabricated by SACNT/PI bilayer structures demonstrate the function of grasping objects on the water surface when electrically Joule-heated, mimicking the predation behavior of water striders. With the synergistic effect of the Marangoni actuator and air-ambient actuators, the MSMR can navigate mazes with tunnels and grasp objects. This research will provide a new inspiration for smart actuators and swimming robots.

Inkjet printing, a non-contact picoliter-level droplet printing method that benefits from a simple procedure, high printing efficiency, mask-free digital printing, and direct pattern deposition, is gradually emerging as a promising technology. The review is anticipated to provide systematic comprehension and valuable insights for inkjet printing, thereby facilitating the advancement of their emerging applications.

Abstract

With the advent of Internet of Things (IoTs) and wearable devices, manufacturing requirements have shifted toward miniaturization, flexibility, environmentalization, and customization. Inkjet printing, as a non-contact picoliter-level droplet printing technology, can achieve material deposition at the microscopic level, helping to achieve high resolution and high precision patterned design. Meanwhile, inkjet printing has the advantages of simple process, high printing efficiency, mask-free digital printing, and direct pattern deposition, and is gradually emerging as a promising technology to meet such new requirements. However, there is a long way to go in constructing functional materials and emerging devices due to the uncommercialized ink materials, complicated film-forming process, and geometrically/functionally mismatched interface, limiting film quality and device applications. Herein, recent developments in working mechanisms, functional ink systems, droplet ejection and flight process, droplet drying process, as well as emerging multifunctional and intelligence applications including optics, electronics, sensors, and energy storage and conversion devices is reviewed. Finally, it is also highlight some of the critical challenges and research opportunities. The review is anticipated to provide a systematic comprehension and valuable insights for inkjet printing, thereby facilitating the advancement of their emerging applications.

MOFs are widely used in various fields such as drug delivery, sensing, and biological imaging due to their high specific surface area, porosity, adjustable pore size, abundant active sites, and functional modification by introducing groups. In this paper, the types of MOFs are classified, and the synthesis methods and functional modification mechanisms of MOFs materials are summarized. Finally, the application prospects and challenges of metal-organic framework materials in the biomedical field are discussed.

Abstract

Metal-organic frameworks (MOFs) are a new variety of solid crystalline porous functional materials. As an extension of inorganic porous materials, it has made important progress in preparation and application. MOFs are widely used in various fields such as gas adsorption storage, drug delivery, sensing, and biological imaging due to their high specific surface area, porosity, adjustable pore size, abundant active sites, and functional modification by introducing groups. In this paper, the types of MOFs are classified, and the synthesis methods and functional modification mechanisms of MOFs materials are summarized. Finally, the application prospects and challenges of metal-organic framework materials in the biomedical field are discussed, hoping to promote their application in multidisciplinary fields.

Nature Photonics, Published online: 16 August 2024; doi:10.1038/s41566-024-01479-y

Based on the acquisition of a multi-spectral reflection matrix at a high frame rate, a fully digital microscope overcomes aberrations and multiple scattering to provide a three-dimensional image of an ex vivo opaque cornea at a resolution of 0.29 μm and 0.5 μm in the transverse and axial directions, respectively.

Air sensitivity remains a substantial barrier to the commercialization of sodium (Na)–layered oxides (NLOs). This problem has puzzled the community for decades because of the complexity of interactions between air components and their impact on both bulk ...

“Can machines think?” So asked Alan Turing in his 1950 paper, “Computing Machinery and Intelligence.” Turing quickly noted that, given the difficulty of defining thinking, the question is “too meaningless to deserve discussion.” As is often done in ...

Electrostimulation Cell Culture Systems

In article number 2315279, Chan Hee Park, Tae Hee Kim, Shi Hyeong Kim, and co-workers present the integrated electrostimulation cell culture system employing twistron mechanical energy harvesters. The twistron harvester generates stretching-induced electrical stimulation and transports it to cells on the conductive scaffold to promote the cells' biological responses.

This study innovatively employs DNA frameworks and hybridization chain reactions to assemble hyperbranched aggregates specifically within cancer cells, achieving dual functions in imaging and regulation and presents a new candidate material for the construction of organelle-like structures.

Abstract

Designing dynamic assemblies in living cells is crucial for creating organelle-like structures, yet precisely controlling their morphological transitions in response to specific signals is a significant challenge. In this study, a DNA framework is combined with hybridization chain reaction (HCR) to achieve specific assembly of hyperbranched aggregates in cancer cells. HCR, distinguished for its signal amplification and linear extension capabilities, enables the morphological transition of precursors to be specifically triggered by trace amounts of endogenous microRNA-21 (miR-21). The spatial constraints of the framework and the diversity of hairpin orientations significantly accelerate the assembly kinetics of hyperbranched networks, and the resulting micrometer-scale aggregates possess enhanced intracellular retention capabilities. Introducing Ce6 molecules as a proof of concept, the regulatory function of aggregates can be activated under light irradiation and remains effective over a long period. The probe we constructed  demonstrates good stability and biocompatibility, offers easy functionalization, and works inside cells long-term, making it an ideal candidate material for the construction of organelle-like structures.

High-performance pressure sensor is reported enabled by nested-cell architecture and molecular surface modification strategy. Benefiting from the large compressible region of modified silicon rubber (MSR), continuous yet large variations of the contacting area, and strong interface bonding interaction, the proposed MSR/FCNT pressure sensor achieves high sensitivity (>28 kPa⁻¹) over 10 MPa sensing range, high pressure resolution, and extreme low/high-temperature resistance.

Abstract

Flexible pressure sensors with high sensitivity over a broad sensing range are of great value in daily life and highly desired in various extreme environment, from human motion inspection to heavy industrial robots to high energy radiation and extremely cold/high temperature environments. However, it remains a significant challenge for a single pressure sensor to simultaneously possess high sensitivity and broad detection range due to the trade-off between these two properties. Here, a high-performance pressure sensor is developed based on flexible modified silicon rubber/functionalized carbon nanotube (MSR/FCNT). The designed nested-cell architecture and molecular surface modification strategy endow the pressure sensor with high sensitivity (>28 kPa⁻¹) over 10 MPa sensing range, an ultralow detection limit (≈0.94 Pa), an ultrahigh pressure resolution (0.0075%) at a pressure of 3 MPa, and a low fatigue over 10 000 repetitive cycles even at an extremely high pressure of 5 MPa. Furthermore, the resulting sensor presents excellent durability after freezing at extreme cold temperature (−80 °C) as well as resistance to high temperature (200 °C) and high-energy X-ray radiation. The proposed nested-cell architecture is a generic strategy for porous materials to achieve broad range high sensitivity.

By doping appropriate amount of nano-ZnO in (Pb,La)(Zr,Sn,Ti)O₃ lead-containing energy storage materials, the sintering temperature is reduced to below 1000 °C and excellent energy storage performance is obtained. This is a key step for the preparation of cheap MLCC by co-firing the energy storage material with Cu inner electrode, and also lays a foundation for subsequent deep ploughing preparation of lead-based Cu-MLCC on this basis.

Abstract

(Pb,La)(Zr,Sn,Ti)O₃-based antiferroelectric ceramics have excellent energy storage performance(more than 90% efficiency), which make them have great application advantages in the field of ceramic capacitors. However, the sintering temperature of (Pb,La)(Zr,Sn,Ti)O₃-based antiferroelectric ceramics is generally above 1250 °C, which limits application as a material for ceramic capacitors. Cu inner electrode has a low co-firing temperature and high conductivity and a low cost price, making it more competitive in the field of ceramic capacitor inner electrode. Therefore, the first step is to reduce the sintering temperature of (Pb,La)(Zr,Sn,Ti)O₃-based ceramics to below 1000 °C(co-firing temperature with Cu inner electrode), which is the key and difficult point. In this paper, Pb_0.94La_0.02Sr_0.04(Zr_0.45Sn_0.47Ti_0.08)_0.995O₃(PLSZST) antiferroelectric ceramics are doped with ZnO, which effectively reduce the sintering temperature. Among them, PLSZST-1 wt% ZnO is sintered at an ultra-low sintering temperature (T _Sintering = 940 °C), which is 330 °C lower than that of PLSZST(T _Sintering = 1270 °C) without doping ZnO. At the same time, PLSZST-1 wt%ZnO obtain a recoverable energy density of 4.26J cm⁻³ and an energy efficiency of 95.5% at 230 kV cm⁻¹. The pulse discharge energy density (W _dis = 3.92 J cm⁻³) and discharge time (t _0.9 = 351 ns) are obtained at 220 kV cm⁻¹, and the current density (C _D = 1338A cm⁻²) and power density (P_D = 134MW cm⁻³) are obtained at 200 kV cm⁻¹. The results provide a possible material basis for Cu internal electrode ceramic capacitors.

Combining comprehensive first-principles calculations and experimental characterizations, this work demonstrates the prevalence of negative longitudinal piezoelectric effect (NLPE) in heteroanionic 2D van der Waals (vdW) layered materials, where only Sb₂TeSe₂ has a giant negative piezoelectric coefficient owing to the cooperative contributions from both volumetric and electronic effects. Experimental measurements performed on Sb₂TeSe₂ further validate its sizable piezoelectric responses.

Abstract

The counterintuitive negative longitudinal piezoelectric effect (NLPE) occurs in those piezoelectric compounds whose electric polarizations are enhanced under the compression stress(strain) applied along the polar axis. Especially, piezoelectric materials with sizable NLPE responses suitable for electromechanical applications are highly desirable. Here, based on comprehensive first-principles calculations and theoretical modeling, NLPE and substantial negative piezoelectric responses are demonstrated to be prevalently attained in various synthetic heteroanionic 2D van der Waals (vdW) layered materials with intrinsic out-of-plane polarizations. Depending on their interlayer spacing percentages and interlayer electronic coupling magnitudes, NLPE in most polar layered materials arise either from the domination of negative “internal-strain” over positive “clamped-ion” contributions, or negative “clamped-ion” over “internal-strain” contributions. As an exception, Sb₂TeSe₂ is predicted to have both negative “clamped-ion” and “internal-strain” terms in considerable magnitudes, contributing cooperatively to overall piezoelectric response and yielding a giant negative longitudinal piezoelectric coefficient d ₃₃ up to –32.666 pC N⁻¹. Furthermore, piezoresponse force microscopy (PFM) measurements performed on Sb₂TeSe₂ crystal verify its non-centrosymmetric structural character and sizable piezoelectric responses. Combining the comprehensive simulations and experimental characterizations, this work deepens the understanding regarding the unusual NLPE, and demonstrates a practical route for screening the polar vdW layered materials with substantial NLPE.

Nano-encapsulated photochromic molecular switches are implanted in the skin to serve as colorimetric ultraviolet (UV) sensors and dosimeters that provide seamless integration with the body and years of service life after a single minimally invasive non-surgical tattoo procedure that requires only seconds of time and milligrams of material.

Abstract

Monitoring personal ultraviolet (UV) exposure facilitates risk mitigation against UV-induced skin aging and skin cancer, the most common malignancy in North America, Europe, and Australia. UV radiometers convey real-time information on local UV irradiance, while UV dosimeters count accumulated UV exposure over time. These devices can help users manage exposure levels in order to reach a healthy daily dose of UV light required for vitamin D production without exceeding erythemal limits that would increase skin cancer risk. However, personal UV detectors still suffer from several limitations. Wearable electronic UV sensors are relatively bulky, heavy, and expensive, while the more commonly used on-skin disposable colorimetric UV sensors suffer from short service life, skin discomfort, and high accumulated costs when used daily as recommended. Intradermal colorimetric UV nanosensors can overcome these limitations, offering long-term, comfortable, and inexpensive naked-eye colorimetric indication of intradermal UV irradiance. Now, a new generation of UV-sensing intradermal pigments with an improved design offers better tunability, stability, and biocompatibility. These UV-photochromic nanosensors may be operated as UV dosimeters or simple sunscreen efficacy monitors, depending on the formulation, and can remain functional and re-usable in the dermis for years.

Rare earth silicide carbide Yb₃Si₂C₂ exhibits high-temperature stability, damage resistance, and remarkable electrical conductivity. Density functional calculations reveal its high reflectivity and low transmittance for terahertz electromagnetic waves, achieving up to 110 dB total shielding effectiveness for 10 µm thickness. These attributes position Yb₃Si₂C₂ as a promising candidate for 6G communications in extreme conditions.

Abstract

The development of next-generation 6G communications is anticipated to expand into extreme environments, necessitating superior terahertz (THz) electromagnetic interference (EMI) shielding materials. Herein, structural stability, electronic and optical properties of rare earth silicide carbide Yb₃Si₂C₂ are investigated using first principles density functional calculations and semi-classical Boltzmann transport theory. The calculation results show Yb₃Si₂C₂ is determined to be experimentally synthesized with high temperature stability with a certain fluctuating C₂ pair orientation. In addition, Yb₃Si₂C₂ is identified as a soft, tough, and damage-resistant ceramic with low shear deformation resistance and easy cleavage, ensuring its durability in irradiation environments. Due to the layered structure and excellent electrical conductivity, Yb₃Si₂C₂ demonstrates high reflectivity and low transmittance for terahertz electromagnetic waves, along with 62% solar absorptivity and 33% IR emissivity. Remarkably, the total shielding effectiveness of Yb₃Si₂C₂ with thicknesses of 5 µm and above follows the widely-used Simon's formula. The average total shielding effectiveness of 5 µm-thick and 10 µm-thick Yb₃Si₂C₂ across the entire THz region reaches 63 and 110 dB, respectively, which turns out to be the top compared to the results reported. Therefore, the multifunctional intrinsic properties of Yb₃Si₂C₂ materials hold great promise for miniaturized, high-performance terahertz EMI shielding, even in extreme environments.

This study uncovers the pivotal role of sulfur evaporation rates in directing the growth modes of MoS₂ on sapphire. Low sulfur levels preserve O/Al-terminated step edges, fostering atomic-edge epitaxy, while high sulfur levels favor S-terminated edges, promoting van der Waals epitaxy. The findings highlight that van der Waals epitaxy achieves superior MoS₂ alignment (≈99%) on a 2 in. wafer, offering new insights into precise 2D material fabrication.

Abstract

Epitaxial growth of 2D transition metal dichalcogenides (TMDCs) on sapphire substrates has been recognized as a pivotal method for producing wafer-scale single-crystal films. Both step-edges and symmetry of substrate surfaces have been proposed as controlling factors. However, the underlying fundamental still remains elusive. In this work, through the molybdenum disulfide (MoS₂) growth on C/M sapphire, it is demonstrated that controlling the sulfur evaporation rate is crucial for dictating the switch between atomic-edge guided epitaxy and van der Waals epitaxy. Low-concentration sulfur condition preserves O/Al-terminated step edges, fostering atomic-edge epitaxy, while high-concentration sulfur leads to S-terminated edges, preferring van der Waals epitaxy. These experiments reveal that on a 2 in. wafer, the van der Waals epitaxy mechanism achieves better control in MoS₂ alignment (≈99%) compared to the step edge mechanism (<85%). These findings shed light on the nuanced role of atomic-level thermodynamics in controlling nucleation modes of TMDCs, thereby providing a pathway for the precise fabrication of single-crystal 2D materials on a wafer scale.

A new non-fullerene acceptor exhibiting an ultralow bandgap of 0.83 eV and strong absorption extending up to 1.5 µm is developed by rationally regulating its molecular packing order. The resulting photodetectors achieve an unprecedented detectivity over 10¹¹ Jones from 0.4 to 1.5 µm with a maximum of 1.68 × 10¹² Jones at 1.16 µm under 0 V bias.

Abstract

The performance of organic photodetectors (OPDs) sensitive to the short-wavelength infrared (SWIR) light lags behind commercial indium gallium arsenide (InGaAs) photodetectors primarily due to the scarcity of organic semiconductors with efficient photoelectric responses exceeding 1.3 µm. Limited by the Energy-gap law, ultralow-bandgap organic semiconductors usually suffer from severe non-radiative transitions, resulting in low external quantum efficiency (EQE). Herein, a difluoro-substituted quinoid terminal group (QC-2F) with exceptionally strong electron-negativity is developed for constructing a new non-fullerene acceptor (NFA), Y-QC4F with an ultralow bandgap of 0.83 eV. This subtle structural modification significantly enhances intermolecular packing order and density, enabling an absorption onset up to 1.5 µm while suppressing non-radiation recombination in Y-QC4F films. SWIR OPDs based on Y-QC4F achieve an impressive detectivity (D*) over 10¹¹ Jones from 0.4 to 1.5 µm under 0 V bias, with a maximum of 1.68 × 10¹² Jones at 1.16 µm. Furthermore, the resulting OPDs demonstrate competitive performance with commercial photodetectors for high-quality SWIR imaging even under 1.4 µm irradiation.

For growing Sn-Pb perovskite single crystals, the oxidation of Sn²⁺ can increase the viscosity of precursor solution and cause an unfavorable solute-diffusion-limited crystal growth mode, leading to curved convex surfaces and non-uniform composition distribution. This problem can be adequately solved with hypophosphorous acid. Based on high-quality Sn-Pb perovskite single crystals, tunable filterless near-infrared narrowband photodetectors with dual detection modes have been demonstrated.

Abstract

Iodine-based Sn-Pb mixed perovskite single crystals (SCs) are promising candidates for near-infrared (NIR) narrowband photodetectors due to their low bandgaps. However, they are highly defective when grown in ambient air due to the extremely poor air stability of Sn²⁺ ions in precursor solutions. It is discovered that the oxidation of Sn²⁺ to Sn⁴⁺ ions not only consumes Sn²⁺ ions but also increases the precursor solution viscosity. The increased viscosity slows down the solute diffusion and hinders the anisotropic growth of SCs, leading to Sn-Pb perovskite SCs with curved convex surfaces and unevenly distributed composition. By preventing the solute-diffusion-limited growth mode with hypophosphorous acid (H₃PO₂), high-quality Sn-Pb perovskite SCs can be robustly grown in ambient air with low trap density of 6.58 × 10⁹ cm⁻³ and high carrier mobility-lifetime product (µτ) of 1.5 × 10⁻³ cm² V⁻¹. Accordingly, a series of filterless NIR narrowband photodetectors with gradually tuned detection centers and dual detection modes has been achieved, delivering a maximum external quantum efficiency of 15.2% and detectivity of 1.19 × 10¹⁰ Jones.

An asymmetric highly aligned all-fiber membrane (HAFM) is created, exhibiting a hierarchical micro-nano structure and excellent mechanical toughness. It shows dual-directional thermal-induced moisture-responsive actuation with huge bending curvature (∼7.23 cm⁻¹) and fast response (0.60 cm⁻¹ s⁻¹). Integrating the actuation-triggered triboelectric effect, programmable micromanipulators, walking robots with self-powered perceptivity, and plant robots with autonomous environment interactions are demonstrated.

Abstract

Soft robots adapt to complex environments for autonomous locomotion, manipulation, and perception are attractive for robot-environment interactions. Strategies to reconcile environment-triggered actuation and self-powered sensing responses to different stimuli remain challenging. By tuning the in situ vapor phase solvent exchange effect in continuous electrospinning, an asymmetric highly-aligned all-fiber membrane (HAFM) with a hierarchical “grape-like” nanosphere-assembled microfiber structure (specific surface area of 13.6 m² g⁻¹) and excellent mechanical toughness (tensile stress of 5.5 MPa, and fracture toughness of 798 KJ m⁻³) is developed, which shows efficient asymmetric actuation to both photothermal and humidity stimuli. The HAFM consists of a metal-organic framework (MOF)-enhanced moisture-responsive layer and an MXene-improved photothermal-responsive layer, which achieves substantial actuation with a bending curvature up to ≈7.23 cm⁻¹ and a fast response of 0.60 cm⁻¹ s⁻¹. By tailoring the fiber alignment and bi-layer thickness ratio, different types of micromanipulators, automatic walking robots, and plant robots with programmable structures are demonstrated, which are realized for self-powered information perception of material type, object moisture, and temperature by integrating the autonomous triboelectric effect induced by photothermal-moisture actuation. This work presents fiber materials with programable hierarchical asymmetries and inspires a common strategy for self-powered organism-interface robots to interact with complex environments.