Advanced Materials Technologies最新文献

This study presents a freestanding sliding triboelectric nanogenerator (FS-TENG) designed for low-frequency motions (below 2 Hz). However, for practical applications, an efficient power management strategy is required to handle the harmonic outputs of the FS-TENG. The high-frequency signal is not sustainable for powering low-power electronic applications. To address the issue, a novel direct current power supply circuit (DPS) is proposed that utilizes a double charge circuit (DCC) and a comb filtering circuit (CFC) to efficiently harness harmonic sources from the FS-TENG. The direct power supply (DPS) outperforms traditional converters by reducing the impedance of the FS-TENG and collecting the target harmonic sources, which facilitates a continuous power supply to the load. The results demonstrate that the DPS is capable of providing a continuous DC voltage of 2.2 V to a 10 MΩ load with minimal ripple (0.039%) at a low operating frequency of 0.625 Hz. Additionally, the practical application of a self-powered temperature sensor is demonstrated to highlight the potential of FS-TENG and DPS for low-frequency energy harvesting solutions in real-world scenarios.

The 3D bioprinting of complex structures has attracted particular attention in recent years and has been explored in several fields, including dentistry, pharmaceutical technology, medical devices, and tissue/organ engineering. However, it still possesses major challenges, such as decreased cell viability due to the prolongation of the printing time, along with difficulties in preserving the print shape. The 4D bioprinting approach, which is based on controlled shape transformation upon stimulation after 3D bioprinting, is a promising innovative method to overcome these difficulties. Herein, the generation of skeletal muscle tissue-like complex structures is demonstrated by 3D bioprinting of GelMA-based C2C12 mouse myoblast-laden bio-ink on a polymeric magnetic actuator that enables on-demand shape transformation (i.e., rolling motion) under a magnetic field. Bioprinted scaffolds are used in both unrolled (open as control) and rolled forms. The results indicate that C2C12s remain viable upon controlled shape transformation, and functional myotube formation is initiated by the 7th day within bioprinted platforms. Moreover, when the rolled and open groups are compared regarding MyoD1 staining intensity, the rolled one enhanced MyoD1 expression. These results provide a promising methodology for generating complex structures with a simple magnetic actuation procedure for the bioprinting of tissue-engineered constructs with enhanced cell viability and functionality.

Anode-free lithium metal batteries have attracted much attention due to their high energy density and lack of excess Li. In this work, Li film is deposited on large-area copper foil (64 cm²) with good uniformity by a self-designed electroplating device that quickly assembles and can be operated outside the glove box. By adding the high concentration of LiNO₃ into the lithium bis(trifluoromethylsulfonyl)azanide (LiTFSI)-based electrolyte, the high Li⁺ conductive solid electrolyte interface (SEI) layer regulated the Li⁺ flux, forming the columnar structure at a high current density of 40 mA cm⁻², and compact morphology at 60 mA cm⁻². Even at 100 mA cm⁻², Li film on copper foil (Li@Cu) maintains its macroscopic uniformity. Furthermore, electrolytes, additives, and temperature are further optimized. The symmetric Li@Cu || Li cell cycle life can extend to 80 cycles. This work provides essential information for future manufacturing processes and scale-up.

This study presents a concept for a straightforward method to enhance the actuation performances of magneto-active elastomer membranes. The concept is based on a characteristic magnetization pattern and offers a solution to two major difficulties in the actuation of thin and mechanically soft magnetic actuators: the localization of actuation forces and the self-demagnetization. After the magnetization process, the membrane presents two regions with an oppositely oriented out-of-plane magnetization. The magnetized regions are separated by a transition zone which is called magnetic pole transition. Experimental investigations reveal a high magnetic flux density near the pole transition—even in the center of bidirectionally magnetized membranes—whereas the magnetic flux density of a uniformly magnetized membrane decreases toward the center. In additional experiments, membranes with both magnetization patterns are actuated by stiff permanent magnets. The resulting out-of-plane displacement of the bidirectionally magnetized membrane exceeds the displacement of the unidirectionally magnetized membrane by far. The investigations demonstrate that this enhancement stems from the presence of the magnetic pole transition. All experiments are reproduced using magnetic and magneto-mechanical numerical models; a good accordance between the results is achieved.

Research on small-scale soft robots has emerged in recent years, and various soft actuators have been developed to implement various actions. Nevertheless, realizing self-sensing alongside environmental sensing capabilities remains a challenge, largely due to the constraints imposed by compact dimensions and the limited load-bearing capacity intrinsic to these robots. In this study, an innovative approach is introduced through the development of a visualized sensing integrated soft actuator, which harnesses the actuator's color as a straightforward and real-time sensing medium. Additionally, a multi-responsive actuation mechanism is adopted in which the actuator responds concurrently to both electric and magnetic fields. To exemplify the efficacy of this concept, the actuators are engineered as flexible soft grippers, thereby accommodating functions encompassing grasping and transporting. Relying on the color distribution manifested by the actuator, the actuator's self-sensing ability alongside its capacity to discern object temperatures is demonstrated. Such a soft actuator provides new perspectives in the realm of soft robotics, showing great potential in diverse robotic applications.

Transport and alignment of microscopic chips are important steps in microelectronics component integration with common approaches being pick-and-place, microfluidics, parallel transfer and self-assembly. An alternate transport approach of microscopic chips is proposed using patterned liquid micro rails as chaperones. The surface free energy and interfacial free energy minimization of all constituents enable the creation of stable pathways. This allows for chip-attachment to rails, while the liquid layer lubricates chip-sliding. Monorails, digital monorails, and digital birails are investigated for chip movement behavior. Chip position and speed can be controlled using liquid flow in closed chambers. Speeds from 10 to 400 mm s⁻¹ are achieved with translation distances as long as 50 mm. It is discovered that chips can selectively cross rail discontinuities of up to 500 µm, allowing for chip position control through a stop-and-go motion. A programmable liquid rails-based chip conveyor system is demonstrated by transporting diodes to receptor sites where they undergo self-assembly.

The composition of the human gastrointestinal microbiota is linked to the health of the host, and interventions targeting intestinal microbes may thus be designed to prevent or mitigate disease. As the spatiotemporal structure and physiology impact the residing bacterial community, local sampling is gaining attention, with various ingestible sampling devices being developed to target specific sites. However, the stomach has received limited attention, despite its potential downstream influence. This work presents a simple ingestible device for gastric fluid sampling and outlines a series of characterizations to ensure device safety, reliability, and accuracy. In vitro testing determined seal effectiveness, mechanical integrity, biocompatibility, and device-sample inertness. In situ and ex vivo testing confirmed sampling accuracy, demonstrated microbiome composition stability for at least 24 h, and differentiation of microbiota between two primates. 16S rRNA gene amplicon sequencing of samples from a porcine ingestion model showed that samples resembled post-mortem gastric samples and differed from fecal and colonic samples. Also addressed in this study, is production scalability and shelf-life to facilitate the safe and effective deployment of devices in clinical settings.

Smart wearable electronic textiles integrate sensing, perception, and control modules, which enhance human adaptability to environmental stimuli and concurrently serve as extensions for limb capabilities. The flexible and programmable nature of soft actuators makes them an indispensable part of smart wearable electronic textiles. These textiles seamlessly combine various components, such as sensors and actuators, through a comprehensive integration of materials manufacturing, circuit control, and transmission design. Exciting applications in various fields such as healthcare, sports, the Internet of Things, and human-machine interaction have been demonstrated globally. However, there is still a persistent challenge in enhancing the actuation capabilities of soft actuators while maintaining their wearability. A timely and comprehensive review of the progress of this field is provided. Several main aspects are covered: functional materials, stimulus mechanisms, performance improvement strategies, and wearable applications in human-related areas. Furthermore, the major approaches and challenges for improving the performance of actuators are systematically summarized.

Architected materials exhibit unique properties and functionalities based on the geometric arrangement of their constituent materials. In most cases, these parameters are fixed, requiring that the system be redesigned and reconstructed if different properties are desired. Both stimuli-responsive materials and modular designs have been used to enable re-programmable properties in the past, but often have limitations, such as the need for a continuous application of external stimuli or power, or unwanted global morphing. In this study, a locally stable anti-tetra chiral (LSAT) metamaterial is introduced consisting of independently multistable units that can deform and change state without inducing changes in the global morphology. Adjacent cells are only weakly coupled, allowing the collective metamaterial to be switched between many different possible states. Local bistability enables re-programmable heterogeneity, such as the snapping of cells along an edge or diagonally within the architected material. Utilizing finite element analysis (FEA), the influence of key geometric parameters on the re-programmability of the metamaterials is systematically investigated. The effect of these parameters on properties such as shear stiffness, Poisson's ratio, and vibration are also investigated using experimental prototypes. This re-programmable metamaterial promises to expand the design space for mechanical systems, with potential applications in non-traditional computation, robotic actuation, and adaptive structures.

With their unique electrical, mechanical, and surface properties, gold nanoparticles (AuNPs) open up new possibilities for sensor technology. In particular, conductive thin films constructed from ligand-stabilized AuNPs are considered an ideal sensing platform due to their high surface area, excellent conductivity, and biocompatibility. However, most methods for making conductive AuNPs thin-film sensors with excellent sensitivity require expensive equipment. In this work, an innovative resistive strain sensor consisting of AuNPs and poly (allylamine hydrochloride) (PAH) based on the mutual adsorption of positive and negative charges using a low-cost layer-by-layer self-assembly (LBL-SA) approach on a flexible polyester substrate is developed. The conductance changes at low temperatures of the AuNPs/PAH agree with the Arrhenius-type activation of charge transport. Additionally, the maximum gauge factor of the sensor is shown experimentally to be ≈656 when 1% strain is applied to the sensor film. This work demonstrates that the sensor detects body motions, eyeball movements, and facial micro-expressions. For detecting eyeball movements and facial micro-expressions, the macro-recall can reach 91.5% and 98.8%. Simultaneously, the sensor can control the virtual avatar's eye movements and human facial micro-expressions in VR. Therefore, nanoparticle-based sensors can be extensively used in future applications related to healthcare and human-computer interaction.