Advanced Materials Technologies最新文献

The current-state of polymer-based humidity sensors faces numerous limitations, including energy-costly synthesis, low sensitivity, and slow response times. This study presents innovative approach to overcome these challenges, based on a robust all-water-borne in situ miniemulsion polymerization. The use of water throughout the entire process mitigates the negative environmental impact. Thiol-ene polymers reinforced with reduced graphene oxide (rGO) with concentrations ranging from 0.2–1.0 wt% are selected to fabricate these chemoresistive sensors. The selected thiol-enes present high hydrophobicity and a semicrystalline nature, suggesting resistance to early delamination even under prolonged exposure to humidity. Incorporating rGO not only imparts electrical conductivity but also enhances mechanical and water resistance of the composite films. The 0.6% rGO composite exhibits optimal resistance for humidity sensing, demonstrating rapid and consistent responses across three exposure cycles to water vapor concentrations ranging 800–5000 ppm. Moreover, the sensor exhibits remarkable selectivity toward water vapors over these of toluene, propanol, and 4-methyl-2-pentanol, attributed to the high surface hydrophilicity and inherent porosity of the waterborne film, and network structuring of rGO platelets within the matrix. In summary, this study pioneers a novel approach to polymer-based humidity sensing, addressing key limitations while offering enhanced sensitivity, rapid response times, and superior selectivity.

Bacterial wound infections are a significant socioeconomic concern in the modern healthcare industry owing to increased morbidity, prolonged hospital stay, and mortality. Bacterial infectious agents that colonize the wound bed develop biofilms, acting as a physical barrier that prevents the effective penetration of topical antimicrobials. Further, bacteria in such infectious wounds express a wide range of virulence factors promoting intercellular transmigration and host cell invasion complicating the treatment regimen. To address this need, a water-dissolvable poly-vinyl pyrrolidine (PVP), calcium peroxide (CPO) infused microneedle structure (denoted as PVP/CPO MN) for effective transdermal delivery of antimicrobial payload deep into the tissues is developed. Fluid exudate from the wound bed dissolves the PVP/CPO MN enabling the release of CPO deep into the infected wound bed. A slow catalytic decomposition of CPO results in the sustained release of reactive oxygen species (ROS) deep within the infected wound inhibiting the inter- and intracellular pathogens. Here, a systematic study of microneedle fabrication and sterilization after complete packaging is conducted to ensure scalability and safe applicability while maintaining mechanical and antibacterial properties. In vitro, antibacterial efficacy of the microneedles is validated against two common wound pathogens, Pseudomonas aeruginosa (P. aeruginosa) and Staphylococcus aureus (S. aureus). Moreover, the PVP/CPO MN exhibited significant efficacy in eradicating both extracellular and intracellular bacterial populations within an in vivo porcine wound model. Additionally, the microneedle technology facilitated a faster wound healing, with ≈30% increase compared to control and a 15% improvement over conventional silver dressing.

The mass production of µLEDs requires an upscaling approach on 200 mm wafers, which implies the deployment of a technology that achieves zero defectivity without liftoff. In this report, Nanoimprint lithography (NIL) processing is successfully optimized for nanostructuring GaN-based Silicon-On-Insulator (SOI) substrates. The etching of SiO₂/GaN/AlN/Si/SiO₂ layers using different plasmas is conducted and multi-layer nanopillars 100–200 mm in diameter are fabricated. This approach generates zero-defect arrays of pillars, which is particularly advantageous for the growth process. In addition, the SiO₂ at the bottom of the pillar allows it to twist during the subsequent GaN regrowth, as this layer becomes soft at the growth temperature >1000 °C. This ability to deform enables a coalescence of pillars into layers with reduced dislocation density. As a result, high-quality GaN microplatelets and µLEDs are grown via a bottom-up approach based on pendeoepitaxy using metal–organic vapor phase epitaxy (MOVPE). The fabricated µLEDs have a very smooth surface with a roughness of 0.6 nm which facilitated the implementation of an easy and simple transfer protocol. Adhesive tape and metalmetal bonding, are used to bond the µLEDs onto a metal-coated silicon substrate. The reported findings offer exciting new insights into the development of high-performance displays.

Sensors have become more versatile and sophisticated in recent years to fulfill the increasing demands for human health applications. Physiological information such as electrocardiogram, pulse rate, and respiration are essential indications of personal health, often collected as vitals, which are typically collected from medical-grade electrocardiogram (ECG) machines. In-textile sensors are a fast-growing sub-category of wearable sensors embedded in smart textiles to acquire physiological information and movement index and provide harmful chemical warnings without compromising the comfortable nature of clothing. Recent literature has shown that integrating new materials has greatly improved the stability, specificity, and selectivity of in-textile sensors. For example, polyvinylidene fluoride nanofiber produced a highly stretchable sensor to measure ECG readings during movement without losing data quality. This review discusses a group of nanomaterial-based in-textile sensors for consumer use in the home, workplace, and healthcare environments. This review will focus on exploring and analyzing the latest developments in these nanomaterial-based e-textiles due to their ability to be more easily integrated for daily use and their great potential for medical applications. Future work will be necessary to incorporate recycled materials, improve the method of powering these sensors, and ultimately refine the designs to be appropriate for more sustainable use.

When drying a colloidal solution, cracks appear in the resulting colloidal film. In certain cases, spontaneous order is observed, and cracks form arrays of periodic patterns. Although this phenomenon might be envisioned as a patterning method, overcoming practical challenges is necessary to transform it into a technological tool for microfabrication. This study explores various technological aspects aimed at leveraging the self-assembly of cracks as a scalable microfabrication tool for large-scale device production. Through a series of analyses, including time-resolved Grazing-Incidence Small-Angle X-Ray Scattering (GISAXS), it is offered novel insights into controlling the crack self-ordering mechanism, minimizing defects, and implementing strategies for large-scale patterning and pattern transfer. The process proves to be surprisingly robust, maintaining its efficacy with the same colloidal solution even after two years. By introducing biphasic dip-coating, large-scale crack patterns up to 100 cm², while preserving their periodicity and ordering is achieved. As a proof of concept, the use of crack-patterned colloidal films as masks for fabricating metallic sub-micrometer objects, that serve as transparent electrodes with adjustable transparency and conductivity is showcased. Overall, this method presents significant advantages over conventional lithography, being cost-effective, versatile, environmentally friendly, and scalable, thereby offering new perspectives for diverse applications requiring cost-effective and large-scale patterning.

This work describes impact of concentration of BiFeO₃ submicrometric particles on piezoelectric performance and structural characteristics of 0–3 polymer composites with a polystyrene matrix. Bismuth ferrite particles are fabricated using reverse co-precipitation method, followed by ultrasonic dispersion in a solvent to break up agglomerates formed during sintering, resulting in particles with a size of ≈200 nm. It is found that concentrations higher than 10 wt% BiFeO₃ lead to a disturbance in natural organization of polystyrene. The hindered organization of side-groups by submicrometric filler, occurring during solvent evaporation, strongly affects the mechanical properties of the finalcomposite, significantly increasing Young's modulus and tensile strength, but decreasing elongation. Such behavior is detected and described for the firsttime in literature. Piezoelectric examinations show that the thermal depolarization of nanogenerators has a different impact depending on the amountof piezoelectric phase. The study reveals that a voltage of over 4.8 V is generated when dynamic air pressure is applied at 11.54 bar for the composite containing only 2.5 wt% BiFeO₃. For composites with 10% weight fraction or lower, decrease in generated voltage after thermal depolarization is about 24%, while for higher weight fractions (15 and 20 wt%) the decrease is around 35%.

The “cloud lab,” an automated laboratory that allows researchers to program and conduct physical experiments remotely, represents a paradigm shift in scientific practice. This shift from wet-lab research as a primarily manual enterprise to one more akin to programming bears incredible promise by democratizing a completely new level of automation and its advantages to the scientific community. Moreover, they provide a foundation on which automated science driven by artificial intelligence (A.I.) can be built upon and thereby resolve limitations in scope and accessibility that current systems face. With a focus on DNA nanotechnology, the authors have had the opportunity to explore and apply the cloud lab to active research. This perspective delves into the future potential of cloud labs in accelerating scientific research and broadening access to automation. The challenges associated with the technology in its current state are further explored, including difficulties in experimental troubleshooting, the limited applicability of its parallelization in an academic setting, as well as the potential reduction in experimental flexibility associated with the approach.

Electroplating

In article number 2400092, Xiuling Li and co-workers introduce a strain-induced self-rolled-up membrane (S-RuM) platform that presents a CMOS-compatible solution for extreme miniaturization and on-chip integration of passive components including inductors and capacitors. By employing post-rolling electroplating on both the walls and core of the curved surfaces of S-RuM inductor arrays, enhancements to the quality factor and inductance can be achieved without sacrificing footprint.

Laser Technology for Perovskite

Laser technology offers a versatile and mask-free method for fabricating, structuring, modifying, and patterning perovskites. It is employed to create perovskite quantum dots, nanowires, nanocrystals, and films. In article number 2302033, Min Gu and co-workers study laser-induced perovskites in glass for their exceptional stability. Multiple applications of perovskite, such as solar cells, LEDs, data storage, optical encryption, photodetection, and lithography, are reviewed.