Magnetic continuum robot (CR) represents a subtype of CRs, which could realize non-contact manipulation through external magnetic field. Their appearance alongside advancements in robotic technology has significantly improved procedures such as flexible endoscopy examinations, microscopic surgeries, and active catheter operations, providing new ideas and approaches for endoscope examination. By using magnetic field, observation and navigation at different positions are achieved by controlling the bending of the flexible endoscope tip through magnetic torque. In this study a design and fabrication approach for miniaturized magnetic flexible endoscope (diameter of 4 mm) was proposed hoping to achieve the functionality of upper gastrointestinal endoscopy. Experimental validation on a 3D electromagnetic platform underscores the flexibility and steerability of the magnetic flexible endoscope, with a mean-square error of 16.52 degrees for maximum bending angle. Additionally, integrating simulation results based on minimum potential energy principle of magnetic potential energy and elastic potential energy has demonstrated precise deformation forecasting, compared with experimental results. The results also indicated that the maximum deflection angle of the magnetic flexible endoscope can reach 164.97 degrees. Magnetic fields in different directions are obtained by varying the current of the power sources. The magnetic flexible endoscope can achieve trajectory motion within a 2D plane along predefined paths. The functionality of the magnetic flexible endoscope has been demonstrated by in vitro model and ex vivo porcine stomach experiments, which showed that magnetic flexible endoscope can bend and deform within the model to observe different positions and even realize the retroflexion capabilities of existing endoscopes. These findings provide a foundation for further development of miniaturized magnetic flexible endoscopic manipulation devices, aiming to improve treatment efficacy and optimize patient treatment experiences.

With the rapid development of adhesives in modern industries, a significant demand has also emerged for more precise and targeted bonding performance, including controllable and remote activation, robust bonding effects, and flame retardancy. Based on microencapsulation technology with controllable interface engineering, a photo/ thermal/force-responsive one-component adhesive is successfully prepared by encapsulating amine into polyurethane (PU)/Diels-Alder-epoxy (DA-EP)/MXene hierarchical shell. PU shell isolated the reactive core from the outer environment and provided a foundation for growing the thermal-response DA-EP layer. Further assembly of MXene nanosheets on the surface of microcapsules enhanced light responsiveness, bonding strength, and flame retardancy for the one-component adhesive, resulting in significant practical benefits. The new one-component adhesive showed significant advantages in peel tests, increasing peel strength by more than twice in some cases. The barrier effect of MXene reduces heat release and traps more combustion products in the condensed phase during the adhesive's burning process. The total heat release of our new one-component adhesive decreased by nearly 25.7 % compared to pure epoxy, and the emissions of toxic CO and smoke also dropped by about 30 %. These innovative one-component adhesives in our work demonstrate exceptional performance and enhance fire safety, highlighting their significant potential in the adhesive industry.

Magnetically actuated small-scale robotic endeffectors offer a promising alternative to conventional cabledriven systems for dexterous surgical applications by eliminating mechanical power transmission, reducing friction, and enabling significant miniaturization. However, many existing systems remain constrained to 1- or 2-degree-of-freedom (DoF) movements, which, while suitable for basic manipulation, still fall short in providing the dexterity required for more complex surgical procedures. This paper introduces a novel design for a 3-DoF magnetic robotic manipulator for soft tissue resection in brain surgery. The proposed system incorporates three orthogonal articulated joints, all actuated by a single onboard magnet, enabling full rotational motion (pitch, yaw, roll) while maintaining a compact and lightweight form factor. Two specialized end-effectors-a 3-DoF rotary cutter and a 3-DoF swing cutter-were developed to demonstrate the versatility of the proposed design in executing precise tissue resection tasks. A kinematic model was formulated to achieve independent actuation of each joint, ensuring dynamic stability through compensation for gravitational and inertial forces. Experimental results demonstrated that the manipulators successfully achieved: (1) 3-DoF motion within a workspace of [360.; -87 degrees to 87 degrees; -83. to 83 degrees] for the swing cutter and [360.; -78 degrees to 78 degrees; continuous rotation] for the rotary cutter; (2) maximum push forces of 20 mN for the swing cutter and 70 mN for the rotary cutter under a magnetic field of just 10 mT; and (3) effective cutting performance in 1% concentration agar gel phantoms. These findings highlight the promise of 3-DoF magnetic robotic manipulators in advancing minimally invasive surgical interventions.

The technological advancements in Digital Light Processing (DLP)-based 3D printing and magnetic photosensitive resins have provided a foundation for the fabrication of magnetic soft structures. Nonetheless, the fabrication of high-performance magnetic soft structures presents significant challenges, primarily stemming from the necessity to balance the concentration of magnetic particles within photopolymer resins and the resin's printability. Herein, we have developed a novel high-concentration NdFeB magnetic photosensitive resin, capable of achieving a magnetic particle concentration of up to 35 wt.%. Concurrently, we have refined the DLP printing technology, successfully enabling the continuous and stable printing of this high-concentration magnetic resin. We have printed complex structures with a maximum structural precision of 100 mu m and a magnetization strength of 21.5 emu & sdot;g-1. The printed structures exhibit an elongation at break of up to 105.3% and an average Young's modulus of 107.5kPa. Furthermore, we have printed a magnetic soft gripper that can grasp objects with a weight up to 1.73 times its own. This study Validates the viability and potential of DLP printing technology in the manufacturing of magnetic soft structures, which could inspire innovative designs and preparations for magnetic soft robots.

Soft structures driven by magnetic fields exhibit the characteristics of being unencumbered and rapidly responsive, enabling the fabrication of various soft robots according to specific requirements. However, soft structures made from a single magnetic material cannot meet the multifunctional demands of practical scenarios, necessitating the development of soft robot fabrication technologies with composite structures of diverse materials. A novel enhanced digital light processing (DLP) 3-dimensional (3D) printing technology has been developed, capable of printing composite magnetic structures with different materials in a single step. Furthermore, a soft robot with a hard magnetic material–superparamagnetic material composite was designed and printed, demonstrating its thermal effect under high-frequency magnetic fields and the editability of the magnetic domains of the hard magnetic material. The robot exhibits a range of locomotive behaviors, including crawling, rolling, and swimming. Under the influence of a 1-Hz actuation magnetic field, the normalized velocities for these modes of motion are recorded as 0.31 body length per second for crawling, 1.88 body length per second for rolling, and 0.14 body length per second for swimming. The robot has demonstrated its capacity to navigate uneven terrain, surmount barriers, and engage in directed locomotion, along with the ability to capture and transport objects. Additionally, it has showcased swimming capabilities within environments characterized by low Reynolds numbers and high fluid viscosities, findings that corroborate simulation analyses. The multimaterial 3D printing technology introduced in this research presents extensive potential for the design and manufacturing of multifunctional soft robots.

The operation of magnetic soft continuum robots depends on external magnetic fields to realize deformation and motion in their flexible magnetic tips, thereby achieving desired functionalities. These magnetic tips essentially behave as flexible cantilever beams. Precise prediction of the deformation behavior in such magnetic soft cantilevers is of critical importance for the design, control, and real-world applications of these robotic systems. The current approach to designing magnetic soft cantilevers predominantly depends on experienced designers refining the design through iterative processes involving extensive simulation and experimentation. Furthermore, studying their mechanical properties and responses typically requires labor-intensive testing or costly computational simulations. Compared to traditional methods, machine learning has revolutionized magnetic soft cantilever design, enabling deformation prediction and geometric generation without prior knowledge. It also shifts the design process from a forward to an inverse approach, eliminating repetitive simulations and offering a faster, more efficient solution. In this study, we introduced a machine learning-based method for forward prediction and inverse design, specifically tailored to magnetic soft cantilever under defined boundary conditions. The forward deformation prediction was carried out using a weighted ensemble method-based multi-layer perceptron (WEM-MLP) machine learning model, followed by simulation and experimental validations. For the inverse design problem, a cascade ensemble method-based MLP (CEM-MLP) model was proposed and validated through simulation. The results confirmed the effectiveness of the proposed methods. The coefficient of determination R2 for forward prediction model reached 0.9962, while R2 for inverse design model was 0.9490. The well-trained machine learning model offers an alternative approach, enabling faster high-precision calculations under resource-limited conditions. This facilitates the prediction of deformation results and inverse design of magnetic soft continuum robots, offering valuable guidance for the practical application of these systems.

Solar-driven steam generation by heat localization has proven to be one of the most promising technologies for broad water-related applications to relieve global water shortage and pollution due to the excellent interfacial water evaporation ability demonstrated both experimentally and theoretically. However, solar power changes fast in practical, such fluctuations on solar energywould invalidate conventional solar evaporator, leave a challenge on sustaining an efficient thermal evaporation. Herein, a mitigating-solar-fluctuation hybrid gel material (MHG) with chemical integrating of phase-change material to achieve efficient steam generation under solar fluctuations is reported. By storing solar energy when it is surplus and providing thermal energy to sustain evaporation when it is insufficient, the MHGs solar evaporator under solar fluctuations achieves optimized water evaporation rate of 1.7 +/- 0.02 kg m-2 h-1 for the high period of 0.8 sun and 1.3 +/- 0.06 kg m-2 h-1 for the low period of 0.5 sun. The MHGs also exhibit outstanding solar desalination performance with good stability and demonstrate an effective brine desalination during round-the-clock desalination process with an average high evaporation rate of 1.24 kg m-2 h-1 d-1. This new material design provides a feasible strategy for solar evaporator to mitigate damage from solar fluctuations. A novel solar evaporator is developed for steady steam generation under fluctuated solar irradiation. The evaporator exhibits an efficient thermal-driven water evaporation under different solar fluctuations and even sustains a long-time effective thermal evaporation during an all-day brine desalination application with outstanding desalination performance. Herein, a feasible strategy for solar evaporator to mitigate damage from solar fluctuations is provided.image (c) 2024 WILEY-VCH GmbH

Even though significant advantages in the energy -free regulation of temperature are presented, the practical applications of radiative cooling materials in buildings and human surfaces still involve many safety issues, especially for fire hazards of polymer -based materials. Meanwhile, renewable and environmentally friendly materials are urgently needed to develop suitable radiative cooling materials with no adverse environmental impact. Herein, a chitosan-derived composite aerogel film with high solar reflection provided by the addition of melamine-phytic acid (MA/PA) hybrids is designed and prepared, presenting radiative cooling and fireproof performances. The instinct deep -yellow color of chitosan (CS) is successfully shielded by high -reflective MA/PA hybrids, while IR emissivity of up to 90.4 % and solar reflectivity of - 89.3 % are achieved. In outdoor environments, this composite aerogel shows sub -ambient temperature drops of - 4.3 degrees C and - 3.1 degrees C in cloudless and cloudy weather, presenting a robust cooling effect. In addition, CS-MA/PA composite aerogel film with 3 mm thickness can isolate the fire of - 500 degrees C, showing superior fire safety attributed to the synergistic flame retardant effects among chitosan, phytic acid, and melamine, which suppress the initial growth of fire and promote the rapid formation of protective char layer. This work provides a bio-based, fire -safe, and radiative cooling material to decrease the energy consumption of temperature regulation with a more environmentally friendly and safer approach, further promoting the practical application of radiative cooling materials.

In recent years, there has been rapid development in magnetic soft continuum robots (MSCRs). MSCRs are facilitated by the uniform dispersion of hard magnetic material particles within elastomers, serving as the actuating source. The external magnetic field interacts with the hard magnetic material to produce magnetic force and/or torque, leading to significant deformation over a wide range. Unlike existing pneumatic or tendon-driven robots, MSCRs do not require additional space or chambers, demonstrating potential for miniaturization. Analyzing the deformation of MSCRs and describing their nonlinear coupled magnetic-elastic deformation behavior is essential, in order to realize the further development and potential applications of MSCRs in various fields. In this study, a deformation model for MSCRs has been developed, which is based on the principle of minimum potential energy. This model accurately predicts the deflection caused by magnetic torque under an external uniform magnetic field. By comparison with experiment results, the proposed deformation analysis model presents a simple and fast modeling process in contrast to existing commercial finite element simulation software. Moreover, the proposed model exhibits good deformation prediction accuracy. By utilizing numerical method in this study to analyze the nonlinear deformation behavior of MSCRs, the constructed model can offer valuable guidance in optimizing the design and control of MSCRs. Furthermore, the deformation analysis conducted on MSCRs can elucidate the feasibility and future potential of realizing their inverse design.

Due to the extreme dynamic weather, important industrial facilities and infrastructure providing vital support for people's lives usually face the hazards of fire and icing, especially in the weather of thunderstorm and ice. Therefore, to further establish a safe community, we develop a dual-functional polyurea (PUA) coating used as protective materials by introducing flame retardancy and solar de-icing performance. Based on the microencapsulation and electrostatic self-assembly technologies, flame-retardant and thermochromic microcapsules (TCM) are firstly prepared and then added into PUA resin, by using melamine resin and bio-based phytic acid/chitosan (PA/CS) hybrids as double-shell materials. The high phosphorus content of PA and the carbon-forming effect of CS together play a synergistic flame retardant effect, not only improving the thermal stability of microcapsules but also enhancing the flame retardant property of PUA coating. In the cone calorimetry test, the ignition time of TCM@PA/CS@PUA-3 is longer, and the pHRR is reduced by 19.93 %, which shows the improvement of flame retardant performance. Due to the thermochromic mechanism, TCM@PA/CS@PUA composite coatings are able to adjust the photo-thermal conversion ability according to different environment temperature, achieving less temperature in hot environment and higher temperature in cold environment. The excellent photo-thermal conversion ability also promotes the ice melting and slide in 525 s. This polyurea composite coating with both flame retardant and de-icing properties shows great potential for maintaining the normal operation and safety of outdoor industrials and infrastructure in extremely dynamic weather conditions.

Magnetic field-driven soft microrobots have widespread applications in biomedical science, microfluidic chips, nanoengineering, and various other domains. However, the existing methods for designing such magnetic-driven flexible robots largely rely on experimental trial and error or steady-state numerical simulated results, which fall short of meeting the intricate requirements for magnetic field editing and magnetic domain distribution. Addressing this issue, a multi-physics coupling numerical analysis method encompassing Magnetic-Fluid-Solid mechanics was developed. A complete process for transient numerical simulation resolution has been achieved. Utilizing this analysis method, the motion patterns of two typical prototypes of magnetic-driven miniature soft bionic robots, a bionic midge larvae robot, and a bionic jellyfish robot, have been analyzed. The central role of the magnetic field in driving these robotic designs—causing deformation in microrobots by designing magnetic domains and spinning the microrobots by controlling the magnetic field—has been revealed. We developed a theoretical model of a bionic fish tail fin robot driven solely by a rotating magnetic field and conducted comparative studies on the swimming efficiency, flexibility, stability, and relative advantages of the three types of robots. The impact of different magnetic domain distribution rules and different magnetic field driving methods on a robot's performance is analyzed, validating that higher swimming efficiency can be achieved by designing a robot's magnetic domains so that they undergo magnetic displacement under magnetic torque resulting in deformation. This innovative analysis method holds potential to provide valuable references for designing motion patterns of magnetically driven microrobots within liquid environments, thereby deepening our understanding toward various complex gait mechanisms involved in biological swimming.

The untethered manipulation of miniature mag-netic mechanisms holds promise for applications in liquid biopsy and drug delivery within the human body. However, employing microrobots for precise liquid manipulation still remains an open challenge. In this study, a novel magnetic mechanism, “magnetic bulb”, which is a millimeter-scale structure resembling pipette rubber bulb, is fabricated using our lab-developed Digital Light Processing-based (DLP-based) 3D printing system. The magnetic bulb can be actuated by magnetic fields to perform various tasks such as sampling, transportation, and controlled release of target liquids. Served as a modular design, the magnetic bulb is assembled with robust external cage to develop an integrated bulb-cage capsule with enhanced sampling capability and resistance to external compression. The resulting capsule has demonstrated effective fluid sampling within a stomach model and drug delivery to biological tissues. Additionally, a magnetic swimmer is crafted by 3D-printing a helical tail onto the magnetic bulb, exhibiting improved locomotion capability and maneuverability by magnetic fields in aerial-aquatic scenarios.

Wearable photothermal materials can capture light energy in nature and convert it into heat energy, which is critical for flexible outdoor sports. However, the conventional flexible photothermal membranes with low specific surface area restrict the maximum photothermal capability, and loose structure of electrospun membrane limits durability of wearable materials. Here, an ultrathin nanostructure candle soot/ multi-walled carbon nanotubes / poly (l-lactic acid) (CS/MWCNTs/PLLA) photothermal membrane is first prepared via solvent-induced recrystallization. The white blood cell membrane-like nanowrinkles with high specific surface area are achieved for the first time and exhibit optimal light absorption. The solvent-induced recrystallization also enables the membrane to realize large strength and durability. Meanwhile, the membranes also show two-sided heterochromatic features and transparency in thick and thin situations, respectively, suggesting outstanding fashionability. Nanowrinkled photothermal membranes by novel solvent-induced recrystallization show high flexibility, fashionability, strength, and photothermal characteristics, which have huge potential for outdoor warmth.

Seasonable and spontaneous replacement approach of daytime radiative cooling to solar thermal conversion is challenging yet imperative for year-round thermal management materials. Meanwhile, the fire safety of thermal management materials is extremely important but often overlooked. Herein, we report a bio-inspired and fireproof aerogel presenting dynamically self-switchable ability of daytime radiative cooling and solar thermal conversion, composed of thermochromic microcapsules (TC), boron nitride nanosheets (BN), and bio-based materials (alginate and phytate). In hot environments, TC/BN composite aerogel shows solar reflectivity of 91.8 % and IR emissivity of 84.3 %, promoting heat radiation to outer space and achieving an average temperature drop of similar to 5.62 degrees C. Attributed to the thermochromic mechanism, TC/BN composite aerogel can harvest visible light of 87 % in the solar spectrum to increase the material temperature by 28.3 degrees C, under an environment of -8.8 degrees C. Based on the EnergyPlus simulation, the employment of TC/BN composite aerogel contributes to decreasing the energy consumption of buildings in both hot and cold regions, including Cairo, Singapore, Alaska, Yakutsk, and so on. Besides, the peak values of heat release rate and total heat release during the combustion of TC/BN composite aerogels are significantly decreased by 70.6 % and 58.4 %, compared to those of TC composite aerogel. The produced protective char layer enhanced by BN nanosheets is capable of isolating the fire and suppressing the fire propagation, improving the fire safety of composite aerogels designed. The TC/BN composite aerogels provide a smart thermal regulation mode for radiative cooling and solar heating, overcome the problems from changing weather and environment, and significantly promote the practical application by enhanced fire safety.

Herein, inspired by the hierarchical structure within the biological protein, we adjust the temperature of the aqueous solution to control the unfolding and reconstitution of hydrogen bonds among melamine (MA) molecules, thus preparing MA-functionalized black phosphorus (MA@BP) nanosheets. As confirmed by the first-principles calculations, melamine can spontaneously adsorb onto the surface of BP nanosheets and enhance the interfacial interactions between BP nanosheets and thermoplastic polyurethane (TPU) matrix. Compared to pure BP nanosheets, MA@BP nanosheets present more efficient suppression effects in heat release and toxic CO production. Besides, due to the photo-thermal conversion effect of BP nanosheets, TPU-MA@BP-2.0 presents an equilibrium temperature of similar to 80 degrees C under simulated sunlight of 1.0 kW/m(2) and a significant solar de-icing performance. The solve-free and hydrogen-bond assembly method not only solves the lack problem of functional groups for the functionalization of BP nanosheets, but also develops a flame-retardant and photo-thermal polymer nanocomposite applied in various occasions.

Magnetically driven miniature soft robots exhibit fast and dexterous responses to an applied external magnetic field. With remote manipulation, controlled navigation of robots can be realized within hard‐to‐access spaces for potential use in the human body. Existing magnetic miniature soft robots using digital light processing are fabricated from planar sheets, and thus have limited shape transformations and locomotive behaviors. Herein, a multilayer 3D printing method is reported for patterning magnetic nanoparticles in ultraviolet (UV)‐curable polymer matrix. Various multilayer 3D structures within 10 mm in overall size are fabricated with controlled volumes at different parts, which outperform 2D folded shapes in terms of robustness and kinematic flexibility. By programming heterogeneous magnetization within discrete multilayer robot segments, magnetic torque‐induced shape changes including gripping, rolling, swimming, and walking are induced by a global actuation field. Stacked design features with minimum dimension of 200 μm and encoded magnetization with resolution of 350 μm can be realized in the printing process. Meanwhile, enhanced deformation flexibility and formation of orientation‐anchoring mechanisms are created by integrating multiple materials with distinct mechanical and magnetic properties, respectively, which enables the creation of versatile 3D multi‐material actuators.

Flexible energy-harvesting materials can adapt to irregular topography and achieve self-supply of power, which has great potential for applications in wearable, surface interface engineering, digital healthcare, etc. MXene, as an emerging two-dimensional material, can be combined with various flexible materials and provide optimized action in energy harvesting. Moreover, the unique structural features of MXene also determine its special physicochemical properties, making it easy to endow MXene-based materials with multifunctional properties. This paper starts with the applications of MXene in different energy capture, including solar energy, thermal energy, mechanical energy and so on. The structure and fabrication process of MXene are also summarized. Afterwards, the realization scheme of MXene-based flexible materials are described in detail. Finally, perspectives of MXene based flexible energy harvesting, especially for wearable self-powered devices, are proposed.

The incompatible interface between carbon nitride (CN) nanosheets and polymer resin is a huge challenge to develop high-performance polymer/CN nanocomposites. Recently, the complicated surface functionalization methods reported severely hinder the commercial production and practical application of polymer/CN nanocomposites. Herein, conducted by the first-principles calculations, a simple surface engineering is put forward to change the surface characteristic of CN nanosheets by rapidly introducing oxygen atoms with a chemical oxidation method. Presented by the first-principles calculations, it is found that the introduction of oxygen atoms can enhance the adsorption energy between oxygen-doping carbon nitride nanosheets (OCN) and waterborne polyurethane (WPU) resin. As a result, a stronger interfacial interaction and better dispersion state are presented in WPU/OCN nanocomposites, thus laying the foundation for the properties enhancement. Further, effective suppression effects for thermal pyrolysis and fire hazards of WPU resin are demonstrated by OCN nanosheets. As presented by cone calorimeter results, the peak values of heat release rate and total heat release in WPU/OCN-2 are decreased to 806 kW/m2 and 43.3 MJ/m2, significantly less than those of pure WPU (1028 kW/m2 and 55.9 MJ/m2). Meanwhile, more char residue, lower signal intensity of pyrolysis gas, and a prolonged time for signal peak also confirm that the addition of 2.0 wt% OCN nanosheets can hinder the thermal degradation behavior of WPU resin. In addition, the introduction of oxygen atoms promotes the formation of hydrogen bond interactions between OCN nanosheets and WPU matrix, thus enhancing interfacial compatibility and overcoming the re-stack problem. As a result, break strength and elongation at break of WPU/OCN-2 are up to 621% and 24.4 MPa, respectively. The combination of first-principles calculations and surface engineering opens a new approach for designing and developing high-performance polymer nanocomposites.

Even though the incorporation of zirconium phosphate (ZrP) nanosheets can enhance fire safety of epoxy (EP) resin, the sole addition of ZrP nanosheets cannot make EP resin pass the UL94 V0 rating and obtain high limit oxygen index (LOI). Meanwhile, traditional intumescent flame retardants (IFR) also deteriorate the mechanical properties of EP/ZrP composites. Herein, for optimizing fire safety and mechanical property, organically modified ZrP (OZrP) nanosheets are prepared based on simple sol-gel chemistry and further combined with IFR to enhance the overall performance of EP composite. Compared to LOI values of pure EP (25) and EP/IFR composite (38), incorporating 2.0 wt% OZrP nanosheets further increase LOI to 44. Meanwhile, EP/IFR/2.0 wt% OZrP composite successfully pass the UL94 V0 rating at the thickness of 0.8, 1.6, and 3.2 mm. As expected, the deterioration of mechanical performance of epoxy resin caused by the addition of IFR is obviously suppressed by introducing OZrP nanosheets, confirmed by impact strength of up to 12.7 kJ/m2 of EP/IFR/3.0 wt% OZrP composite. In the cone calorimeter test, the combination of 2.0 wt% OZrP and 20.0 wt% IFR significantly de-creases the peak value of heat release rate and total heat release of EP resin by 83.9 % and 59.7 %. According to the microstructure and chemical composition of char residue, an intumescent and graphitized char formation mechanism is raised for the significantly enhanced fire safety in EP/OZrP/IFR composites. The optimization effect of OZrP nanosheets in the fire safety and mechanical property of epoxy/intumescent flame retardant composites further promote the practical application of epoxy resin.