Advanced Materials Technologies最新文献

In this work, the development of a flexible Double-Gate (DG) organic thin film transistor (DG-OTFT), and its employment is reported for the realization of multimodal tactile sensors. Due to the self-encapsulation of the stacked DG architecture, highly stable organic transistors are obtained that show almost negligible degradation after 6 months. Moreover, such configuration is also very useful for the development of sensing devices. In the case, one of the two gates is used to bias and set the working point of the devices, whereas the second one is connected to a polyvinylidene fluoride(PVDF)-capacitor, a pyro/piezoelectric material. It is demonstrated that the charge displacement induced by the PVDF capacitor due to an applied external pressure or due to a temperature variation led to a reproducible variation of the device's output current. Using this approach high-performing multimodal tactile sensors are obtained with sensitivity to up to 241 nA N⁻¹ and 442 nA °C⁻¹ respectively.

Structural supercapacitors that simultaneously bear mechanical loads and store electrical energy have exciting potential for enhancing the efficiency of various mobile systems. However, a significant hurdle in developing practical structural supercapacitors is the inherent trade-off between their mechanical properties and electrochemical capabilities, particularly within their electrolytes. This study demonstrates a tough polymer electrolyte with enhanced multifunctionality made through the controlled hydration of a solid polymer electrolyte with poly(lactic acid) (PLA) and lithium salts. Characterization via differential scanning calorimetry, X-ray diffraction, and Fourier transform infrared spectroscopy confirms the consistent amorphous solid solution phase in varying salt concentrations, whether dried or hydrated. Electrochemical tests and tensile tests are performed to evaluate the ionic conductivity and mechanical properties of these electrolytes. The results indicate that the strategic incorporation of water in the polymer electrolyte significantly enhances the ionic conductivity while preserving its mechanical properties. A specific composition demonstrated a remarkable increase in ionic conductivity (3.11 µS cm⁻¹) coupled with superior toughness (15.4 MJ m⁻³), significantly surpassing the base polymer. These findings open new horizons for integrating electrochemical functionality into structural polymers without compromising their mechanical properties. Additionally, the paper reports the successful fabrication and testing of structural supercapacitor prototypes combining carbon fibers with fabricated electrolytes, showcasing their potential for diverse applications.

In the treatment of kidney diseases such as chronic kidney disease (CKD) and acute tubular necrosis (ATN), prolonged contact between conductivity sensors and patients' bodily fluids is required, necessitating high biocompatibility for the electrodes. However, the widely used graphite electrodes exhibit limited biocompatibility, showing a cell survival rate of only 88% under indirect contact conditions, and <56% under direct contact conditions. Here, the surface detachment of graphite electrodes in liquid environments leading to cell death upon contact is observed and a solution is proposed to enhance biocompatibility and ensure conductivity, by forming a layer of interface-stable coating (ISC) as a conductive isolation membrane on their surface. For applications with contact requirements, graphite-like carbon (GLC) coated graphite electrodes are investigated and developed, resulting in an exceptional cell survival rate exceeding 96% under indirect contact conditions, and a relatively high survival rate exceeding 91% under direct contact conditions, both accompanied by significant proliferation. GLC-coated graphite electrodes are successfully to monitor the dialysate conductivity in a hemodialysis machine and achieve stable monitoring with temperature compensation. The results demonstrate ISC graphite electrodes' potential in biomedical fluid monitoring, with the developed process applicable to other fields.

It is demonstrated that single-crystalline and highly doped GaAs membranes are excellent candidates for realizing infrared-transparent shields of electromagnetic interference at millimeter frequencies. Measured optical transmittance spectra for the semiconductor membranes show resonant features between 750 and 2500 nm, with a 100% maximum transmittance. The shielding effectiveness of the membranes is extracted from measured scattering parameters between 65 and 85 GHz. Selected GaAs membranes and membranes/polyamide films exhibit shielding effectiveness ranging from 22 to 40 dB, which are suitable values to ensure the safe operation of infrared devices for commercial applications. Theoretical calculations based on a plane wave model show that the interplay of primary reflection and multiple internal reflections of the radio-frequency waves results in broadband shielding capabilities of the membrane between 10 and 300 GHz.

Numerous diseases, including age-related macular degeneration (AMD), arise from the blood-retinal barrier and blood vessel abnormalities in the eye; unfortunately, there is a lack of reliable in vitro models for their systematic study. This study describes a high-throughput microphysiological system (MPS) designed to model the outer Blood-Retinal Barrier (oBRB). The MPS platform is engineered to integrate seamlessly with high-content screening technologies, utilizing a design with a single oBRB model incorporating RPE (retina pigment epithelial cells) and endothelial cell co-culture to fit within a single 96-well. Arranged in the standard 96-well plate format, the platform allows high-throughput assessment of barrier integrity through 3D confocal imaging (ZO-1 staining), Trans Epithelial Electrical Resistance (TEER), and permeability measurements. The oBRB model enables the investigation of crosstalk among different cell types in co-culture. This includes assessing changes in the barrier integrity of the Retinal Pigment Epithelium (RPE) monolayer and investigating neovascularization events resulting from endothelial cell remodeling. The platform is positioned for utility in drug discovery and development efforts targeting diseases involving oBRB damage and choroidal neovascularization, such as age-related macular degeneration.

In recent years, the convergence of smart electronic textile (e-textile) and digital technology has emerged as a transformative shift in healthcare, offering innovative solutions for point-of-care diagnostics. However, the development of textile electronics with exceptional functionality and comfort still remains challenging. Here, all-electrospun piezoelectric smart e-textile empowered is reported by Internet of Things (IoT) and machine learning for advanced point-of-care diagnostics. The resulting e-textile exhibits exceptional breathability (b ≈ 4.13 kg m⁻² d⁻¹), flexibility, water-resistive properties (water contact angle ≈137°), and mechano-sensitivity of 1.5 V N⁻¹ due to its mechanical-to-electrical energy conversion abilities. It can efficiently monitor different critical biomedical healthcare signals, such as, arterial pulse and respiration rate. Importantly, the e-textile sensor demonstrates remarkable attributes, generating an open circuit voltage of 10.5 V, a short circuit current of 7.7 µA, and power density of 4.2 µW cm⁻². Moreover, the e-textile provides real-time, non-invasive monitoring of human physiological movements through IoT. It is worth highlighting that the machine learning showcases an impressive 96% of accuracy in detecting respiratory signals, representing a significant accomplishment. Thus, this e-textile has enormous potential in remote patient monitoring and early disease detection, aiming to reduce healthcare costs, enhance patient outcomes, and improve the overall quality of medical care.

3D printing provides the potential to enhance mechanical properties by fabricating complex structures with diverse materials; however, most high-resolution 3D printing techniques require custom printers to incorporate multiple materials and/or result in poor material interfacial bonding. Here, energy absorption properties are enhanced with 3D lattice structures fabricated via vat photopolymerization comprising multiple materials forming a gradient-interpenetrating polymer network (gradient-IPN). The gradient-IPN is incorporated by swelling the 3D printed elastomeric lattice in a photoresin that yields a stiff shell-soft core structure. This straightforward post-3D printing technique delivers an unprecedented degree of structural property customization through polymer gradients in lattice struts with shells of tunable stiffness and flexible elastomeric cores to achieve a broad continuum spectrum of mechanical properties within one simple system. The gradient aids in the distribution of stress and limits fracture between materials typically observed in multimaterial lattices. The gradient-IPN lattices are fully recoverable and exhibit over 4 to 33 times higher toughness after compression, compared to copolymer (same composition as the gradient-IPN) or purely elastomeric lattices, respectively. This highly versatile approach to modifying 3D printed lattices yields the unique combination of load bearing capabilities with viscoelasticity desirable for high performance materials in impact protection.

2D materials like transition metal dichalcogenides (TMDCs) have been widely studied and are a gateway to modern technologies. While research today is mostly carried out on a laboratory scale, there is an intensive need for reliable processes on a wafer-scale, starting with monolayer-precise deposition of high-quality films. In this work, a plasma-enhanced atomic layer deposition (PEALD) process is developed on a 200 mm SiO₂/Si substrate. The layers are investigated regarding crystallinity, composition, homogeneity, microstructure, topography, and electrical properties. The process is then applied on 200 mm alkali-free glass wafers aiming toward flexible electronics and compatibility with Si processes. A complete coverage of the wafer with a satisfying uniformity is achieved on both substrates and direct polycrystalline growth of MoS₂ films is verified on the entire wafer at a substrate temperature of T = 230 °C. On glass, the deposited MoS₂ films exhibit a higher crystallinity and are more planar compared to the SiO₂/Si substrate. Furthermore, application relevant few-nanometer thick layers are investigated in detail. This low-temperature process inspires optimism for future direct integration of 2D-materials in an economical bottom-up approach on a wide variety of substrates, thus paving the way for industrial mass production.

Benefiting from their large second-order nonlinear coefficients and high integration capabilities, crystalline lithium niobate (LN) films have shown great application prospects in the field of nonlinear metasurfaces. It is necessary to endow LN metasurfaces with optical resonances to further boost nonlinear optical responses. Among these optical resonances, anapole resonances carried by LN metasurfaces have been predicted to efficiently enhance second harmonic generations (SHG) but have never been experimentally realized. Anapole resonance requires ideal nanostructures to have steep sidewalls and a high filling ratio, but the intrinsic hardness and inert chemical properties of LN materials pose great challenges for the fabrication of LN nanostructures. Here, a multi-gas component dry-etching technique is proposed to prepare various LN nanostructures, achieving typical LN nanopillar arrays with a sidewall angle of ≈85° at a depth of 300 nm and a filling ratio of 52%. Importantly, nanostructured LN metasurfaces are designed and fabricated to experimentally realize anapole resonances at a fundamental wavelength of ≈800 nm, demonstrating a ≈30-fold enhancement in second harmonic generation compared with bare LN films. The work provides promising strategies for the versatile fabrication of LN nanostructures and their applications in nonlinear meta-optics.

The high crystallinity and sophisticated hierarchical architecture of native animal silk endow it with comprehensive mechanical properties that are superior to those of most synthetic fibers. However, these features also make the direct exfoliation of silk nanofibrils (SNFs) highly challenging. On the other hand, silk-based materials prepared by conventional method (i.e., through silk fibroin aqueous solution) are usually weak, so the preparation methods based on SNFs have attracted much attention in recent years. Herein, a facile and environmentally friendly route is developed to directly exfoliate SNFs from natural Bombyx mori silkworm silk via ammonium persulfate oxidation followed by ultrasonication. The obtained SNFs have a high yield (nearly 40%) and are well dispersed in water in a wide pH range, so they can act as a good starting material to prepare subsequent silk-based materials. The main application of the SNFs demonstrated in this article is a curcumin (Cur)/SNFs hydrogel as wound dressing. In vivo experimental results show that the Cur/SNFs hydrogel significantly enhanced the healing rate of wounds on diabetic mice. Therefore, the preparation method developed in this study provides an efficient way to produce SNFs, which have great potential for a wide range of applications, including as wound dressings for diabetics.