Advanced Materials Interfaces最新文献

The present work addresses the systematic accurate fabrication and design of biphilic surfaces having superhydrophobic circular islands surrounded by a hydrophilic background by investigating their condensation frosting and defrosting behavior. A significant delay in frost formation is observed on samples with higher superhydrophobicity ratio A^*, defined as superhydrophobic area to total area ratio. As the superhydrophobic island diameter D increases from D = 500 µm to D = 700 µm (A^* from 19.62% to 38.46%), a 50% improvement/delay is observed in terms of frost formation or densification. Besides delaying icing/frosting, the presence of superhydrophobic areas empowers the formation of porous and nonuniform frost structure, which facilitates ice removal during the defrosting process. To this end, as the surface is recovered the ambient temperature, almost complete passive cleaning performance within only 23 s is observed on the biphilic design having superhydrophobic islands with the diameter of D = 500 µm, that is, a superhydrophobicity ratio A^* of 19.62%. This work concludes on the optimum biphilic ratio, which is not only effective as a passive method by hindering frosting but also leads to a slush/water free surface after defrosting eased by the Laplace pressure gradient which is imposed by the different biphilic wettability patterns.

Casimir forces arise if the spectrum of electromagnetic fluctuations are restricted by boundaries. There is great interest both in fundamental science and technical applications to better understand and technically control these forces. In this work, the influence of five different self-assembled bio and organic monolayer thin films on the Casimir force between a plate and a sphere is experimentally investigated. It is found that the films, despite being a mere few nanometers thick, reduce the Casimir force by up to 14%. Spectroscopic data indicate a broad absorption band whose presence can be attributed to the mixing of electronic states of the underlying gold layer and those of the molecular film due to charge rearrangement. Using Lifshitz theory, it is calculated that the observed change in the Casimir force is consistent with the measured change in the effective dielectric properties. The nanometer-sized molecules can penetrate small cavities, and cover any surface with high efficiency. This process seems compatible with current methods in the production of micro-electromechanical systems (MEMS), which cannot be miniaturized beyond a certain size due to ‘stiction’ caused by the Casimir effect. This approach can therefore offer a practical solution for this problem.

Hydrogel foams are widely used in many applications such as biomaterials, cosmetics, foods, or agriculture. However, controlling precisely foam morphology (bubble size or shape, connectivity, wall and strut thicknesses, homogeneity) is required to optimize their properties. Therefore, a method is proposed here for generating, controlling, and characterizing the morphology of hydrogel foams from liquid foam templates: Using the example of Alginate-CaHPO₄-based hydrogel foams, a highly controllable foaming process is provided by bubbling nitrogen through nozzles into the solution, which produces hydrogel foams with millimeter-sized bubbles. A rheological characterization protocol of the foam's constituent material is first implemented and highlights the impact of the initial liquid foam properties and of the competition between the solidification kinetics and the foam aging mechanisms on the resulting morphology. X-ray tomographic characterization performed on solidifying and solidified samples then demonstrates that by controlling the temporal evolution of the foam via its formulation, it is possible to tune the final morphology of the alginate foams. This method can be adapted to other hydrogel or polymer formulations, foam characteristics and length scales, as soon as solidification processes happen on timescales shorter than foam destabilization mechanisms.

Environmental disease monitoring initiatives such as wastewater-based epidemiology can offer a unique perspective on the health status of a population. Such efforts are being increasingly utilized to guide public health initiatives and to aid in controlling the spread of infectious diseases. Key to these approaches is the sampling and identification of viruses, bacteria, and other pathogens. Advanced material technologies can be explored for the development of materials suitable for sampling, leading to the retention and detection of viruses. Here, how the surface interactions between viruses and adsorbent materials can inform the future development of effective, novel materials to aid in sampling viruses for wastewater-based epidemiology are considered. This review provides a summary of the surface properties of viruses along with their physiochemical interactions with adsorbent materials at the solid-water interface. Also discussed are the properties of non-woven polymer membranes, a newer material technology being employed for the retention of viruses, with a focus on virus-capture applications in aqueous environments.

In this study, the origins of efficiency gains in Cu(In,Ga)Se₂ (CIGS) solar cells are investigated by introducing an Al₂O₃ passivation layer in terms of the oxidation condition of Mo back contact, alkali-metal diffusion, minority carrier lifetimes (τ), and charge conditions. The study reveals that introduction of an Al₂O₃ back-contact passivation layer into solar cells yields multiple impacts. Al₂O₃ deposition enhances the oxidation of the Mo back contacts, increasing Na solubility in Mo and Na diffusion from Mo into the CIGS layer, thereby modifying the metastable properties of CIGS. The charge condition at the CIGS/Al₂O₃ interface is not fixed negative charge but variable, dependent on whether electrons or holes are supplied. During solar cell operation, the interfacial charge condition is expected to be neutral or positive for Al₂O₃ grown using plasma or thermal atomic layer deposition techniques, respectively. Moreover, the mechanical peeling off of CIGS from Mo back contact enhanced τ in a similar way as with the insertion of Al₂O₃. Based on this study, the enhancement of alkali metal supply and the removal of direct contact of CIGS to the metal contact (Mo) can play crucial roles in improving the performance of CIGS solar cell.

Long-Term Water Resistance Stability

In article 2400144, Seok Kim, Young Tae Cho, and co-workers show the variation in contact angle based on the pattern when two water-repellent surfaces, one consisting of a Hexagon Grid Pattern (HGP, on the right) and the other a Hierarchical Hexagon Grid Pattern (H-HGP, on the left), are immersed in water and subsequently removed. Upon removal from water, the HGP retains its hydrophobic properties, whereas the H-HGP transitions to hydrophilic.

Lateral Flow Assays (LFAs) are cost-effective and widely utilized for rapid diagnostics, yet they often suffer from limited sensitivity. This study introduces a straightforward yet highly effective method to enhance LFAs performance by integrating a poly(ethylene glycol) diacrylate (PEGDA) hydrogel to create a “reaction trap.” This hydrogel reaction trap optimizes the flow rate and reaction time at the sensing components, substantially improving assay performance. By applying various hydrogel concentrations (6%, 9%, 12%, 15%, and 18% w/v), significant enhancements across a range of detection systems are achieved. An optimized 18% hydrogel concentration shows a 1.5 times increase in sensitivity in the tested commercial pregnancy test. Additionally, 12% hydrogel concentration is tested in pregnancy, ovulation, and Coronavirus disease 2019 (COVID-19) commercial kits, and the improvement reached up to a sevenfold increase in signal intensity. The enhancement in detection illustrates the profound impact of this simple modification and shows the importance of hydrogel concentration optimization to maximize detection improvement. These results demonstrate that hydrogel-coated LFAs offer a scalable and highly effective solution for boosting the reliability and sensitivity of rapid diagnostics across different healthcare settings, with broad potential for global health diagnostics applications.

Considering the increasing demand for personalized surgical care, as well as current healthcare resources limitations, the use of anatomical accurate 3D physical phantoms is becoming increasingly important for the training of surgeons and the test of surgical instruments. A lack of physical models is nowadays denoted regarding the training in electrosurgery, despite its wide diffusion in medical practice. This work reports an extensive characterization of electrosurgical physical phantoms fabricated with tissue-mimicking ionogels and hydrogels. A careful design of the conductive gels allow the fine tuning of their mechanical and electrical properties, in order to match those of biological tissues. The manufacturing of a novel multi-material skin stratification bench-top pad is reported together with its use for training in both cold and electrical surgery. Furthermore, a feasibility study is reported, showing the use of conductive ionogels for simulating the coagulation of cortical vessels during brain surgery.

Molybdenum Trioxide (MoO₃) is a promising candidate as an anode material for lithium-ion batteries (LIB), with a theoretical capacity of 1 117 mAhg⁻¹. Nevertheless, MoO₃ has inherent lower electronic conductivity and suffers from significant volume expansion during the charge–discharge cycle, which hinders its ability to attain a substantial capacity and cyclability for practical applications. In this study, a novel material design strategy is reported for LIB anodes containing MoO₃ and hard carbon (HC) architecture fabricated using a Physical Vapor Deposition (PVD) technique. MoO₃/HC as anode materials are evaluated for LIBs, which demonstrate an exceptional performance with a capacity of 953 mAhg⁻¹ at a discharging rate of 0.2 C. Additionally, MoO₃/HC anode demonstrated exceptional rate capability during fast charging at 5 C and achieved a capacity of 342 mAhg⁻¹. The MoO₃/HC anode demonstrates remarkable cycle life, retaining over > 99% Coulombic efficiency after 3 000 cycles at a rate of 0.2 C. The exceptional performance of MoO₃/HC anode can be attributed to the novel material design strategy based on a multi-layered structure where HC provides a barrier against the possible volumetric expansion of LIB anode.