Advanced Materials Technologies最新文献

Stretchable devices have gained increasing interest in recent years, particularly in the field of wearable electronics. Among them, fiber-type devices with high mechanical conformability hold great potential to enable next-generation wearable and interactive applications with their special structure and high compatibility with the well-established textile industries. In this study, a hydrogel fiber providing large moisture retention and high mechanical compliance is fabricated, with which a new approach to enable highly stretchable electromechanical sensors based on knot structures is developed. Comparative analysis with common orthogonal textile structures reveal the superior performance of sensors based on ionotronic knots. Stress sensors with the double overhand knot exhibit ≈four times greater variation in capacitance than those with orthogonal structures, and sensors with the clove hitch knot exhibit a fast response time of 57 ms. Based on the characteristics of different knots, a sensor matrix based on clove hitch knots to map the pressure distribution, and a wearable mole code generator based on reef knots to recognize and encode wrist motions are developed. These applications demonstrate the excellent performance of knot-architecture sensors and their great potential in the fields of smart fabrics and human–machine interactions.

Many novel transport phenomena are observed in graphene nanochannels with ultrahigh surface flatness and nano- or sub-nanoscale constraints. Two critical physical parameters, surface slip length, and surface charge, play a vital role in the channel transport process. However, effectively controlling these parameters under such tight constraints remains a significant challenge. Here, it is developed a novel method that combines oxygen ion etching and layer-by-layer assembly of 2D material, to prepare graphene nanochannels. During the assembly process, defects are introduced into the graphene surface via oxygen ion etching. A significantly higher conductivity is observed for the pristine graphene channels compared to those with defects on both the upper and lower surfaces. Consistent with this observation, the conductivity of graphene channels with defects on only one surface falls between the two aforementioned values. Combined with theoretical analysis, the conductivity difference is attributed to the surface slip inhibition due to the introduced defects, and the change of surface charge, both caused by oxygen ion etching. By introducing defects, a new method is uncovered for fine-tuning ion transport in graphene nanochannels.

The nature of rigidity and low energy density of polypyrrole (PPy)-based electrodes limits their wide application in flexible energy storage devices. In this study, reduced graphene oxide (rGO) wrapped polypyrrole (PPy)/oxidized carbon cloth (OCC) (rGO@PPy/OCC) is prepared by the polymerization of pyrrole using MnO₂ as the oxidant on the surface of OCC followed by the adsorption and reduction of graphene oxide (GO). The prepared rGO@PPy/OCC electrode exhibits a high gravimetric specific capacitance of 547 F g⁻¹ at a current density of 0.5 A g⁻¹ and a high area specific capacitance of 1641 mF cm⁻² at a current density of 1.5 mA cm⁻². It nearly maintains the initial capacitance after 8000 cycles at a high scan rate of 200 mV s⁻¹ and at a large current density of 10 A g⁻¹. Moreover, the flexible rGO@PPy/OCC electrodes are used to construct flexible solid-state supercapacitors (FSSC). The FSSC based on rGO@PPy/OCC exhibits a high energy density (33.89 Wh kg⁻¹ and 101.81 µWh cm⁻²) and a capacitance retention of 95.10% after 1000 bending cycles, demonstrating the excellent cycling stability and flexibility. Therefore, it is potential for rGO@PPy/OCC as a flexible electrode to fabricate high-performance FSSC.

Transwell-based airway models have become increasingly important in studying the effects of respiratory diseases and drug treatment at the air–liquid interface of the lung epithelial barrier. However, the underlying mechanisms at the tissue and cell level often remain unclear, as transwell inserts feature limited live-cell imaging compatibility. Here, a novel microfluidic platform is reported for the cultivation of transwell-based lung tissues providing the possibility to alternate between air–liquid and liquid–liquid interfaces. While the air–liquid interface recapitulates physiological conditions for the lung model, the liquid–liquid interface enables live imaging of the tissue at high spatiotemporal resolution. The plastics-based microfluidic platform enables the insertion and recuperation of the transwell inserts, which allows for tissue cultivation and analysis under standardized well plate conditions. The device is used to monitor infections of Pseudomonas aeruginosa in human stem-cell-derived bronchial epithelial tissue. The progression of a P. aeruginosa infection in real-time at high resolution is continuously imaged, which provides insights into bacterial spreading and invasion on the apical tissue surface, as well as insights into tissue breaching and destruction over time. The airway tissue culture system is a powerful tool to visualize and elucidate key processes of developing respiratory diseases and to facilitate drug testing and development.

The constant improvement of stereolithography (SL) in terms of achievable resolution and printing time has sparked high expectations that SL will enable the rapid prototyping of truly microfluidic chips with features below 100 µm. However, most commercial high-resolution stereolithography devices are based on Digital Light Processing (DLP) and thus sacrifice lateral printing size for resolution. Consequently, even 10 years after the advent of microstereolithography there is no commercialized 3D printing system that can effectively fulfill all the demands to replace soft lithography for microfluidic prototyping. In this work, for the first time, This study demonstrates that a commercial laser-based stereolithography device is capable of manufacturing microfluidic chips with embedded channels smaller than 100 µm with a footprint of 7.24 × 0.3 cm². A chip fabricated in poly(ethylene glycol) diacrylate (PEGDA) that can readily be used for fluid mixing, is presented in this study. This research shows that the accessibility of high-resolution chips with footprints of several cm², using laser-based stereolithography, enables the manufacturing of truly microfluidic systems with high impact on prototyping and manufacturing.

H₂ Gas Detection

In article number 2302081, Mikhael Bechelany, Lionel Santinacci, Hyoun Woo Kim, Sang Sub Kim, and co-workers describe the development of a highly sensitive and selective H₂ gas sensor. This sensor utilizes ZnO nanowires (NWs) decorated with Pd nanoparticles (NPs) and a NiO shell layer, all deposited via atomic layer deposition. This sensor demonstrates high sensitivity and selectivity to H₂ gas even in the presence of H₂/CO and H₂/NO₂ gasmixtures, offering potential for highly selective H₂ gas detection.

Additive manufacturing of freeform structures containing multiple materials with deterministic spatial arrangement and interactions remains a challenge for most 3D printing processes, due to complex fabrication tool requirements and limitations in printability of some material classes. Here, a versatile method is reported to produce architected composites using the concept of cellular fluidics, in which lattices of unit cells are used as templating scaffolds to guide flowable infill materials in a programmed spatial pattern, upon which they are cured in place to produce a deterministically ordered multimaterial solid. The lattice design relies on the unit cell size, type, strut diameter, surface wetting, and distribution of cellular structures to control liquid flow and retention. Individual unit cells are tuned to achieve reliable infilling and combined into higher-order architectures to achieve multiscale composite materials with disparate mechanical properties, including those considered non-printable. Lattice design considerations for leveraging capillary phenomena and demonstrate several methods of patterning polymers in 3D-printed cellular fluidic structures are presented. The concept of tuning the compressive response of an architected composite using a flexible-elastomer as the lattice and a stiff-epoxy as the infill material is illustrated.

Gold Nanostructured Arrays

In article number 2400019, Qian Zhao, Weiping Cai, and co-workers fabricate a variety of gold nanostructured arrays based on a bowl-shaped tin oxide secondary template with fine structure on its bowl edges, including ‘graphene-structured’ nanoarrays, non-contact nanoparticle ring arrays, closely-contacted nanoring arrays and bowl/nanoparticle binary composite nanoarrays, achieving structural diversity and morphologicalmodifiability. These nanoarrays exhibit structure-induced hydrophilic-hydrophobic transition and a target molecular trapping effect.

Ferroelectric Programmability

In article number 2301562, Osama R. Bilal and Mohamed Roshdy harness electric poling of ferroelectric polymers to program the local stiffness of their metamaterials in a pixelwise fashion. The programmed path can have dynamical properties that are different from the surrounding pixels. The programming can reverse the metamaterials' behavior from attenuating waves to propagating them and vice-versa. These findings advance the applications of elastic waves tunning and control in metamaterials.