The research demonstrates a new method for preparing flexible microcircuits and conductive sheets from liquid metals. The microcircuit carved on the surface of a liquid metal deposit has good conductivity, which greatly reduces the possibility of an open circuit.

Abstract

Liquid metal (LM) is of great use in many fields (e. g., sensors, biology, electronic circuits). With special mobility, high surface tension and excellent electrical conductivity, it can play a role in the field of flexible electronics. Due to its surface tension, it easily shrinks into a spheroid shape. Especially under the same current condition, the shrinkage of the volume will lead to open circuit, so it is very difficult to produce stable liquid metal ultrathin, ultrafine wire, which has become a barrier limiting the use of liquid metal. In this work, LM is mixed with polydimethylsiloxane to form a micrometer-thick conductive layer by free deposition. The LM is located inside the polymer holes. Not only that, microcircuits are also mapped on the surface of LM deposits. It not only has excellent electrical conductivity, but also has good flexibility. This work explores a simple method to produce a ultrathin conductive film and reduce the size of electronic components, which has potential applications in integrated circuits.

Ultrafine and highly dispersible MnO₂ nanoparticles were synthesized by hydrothermally reducing KMnO₄ with (NH₄)₂HPO₄ as the reductant. The MnO₂ nanoparticles prepared via this method exhibited excellent dispersibility in water, as well as a high specific capacitance of ~135.7 F ⋅ g⁻¹ at 5 mV ⋅ s⁻¹. This method is an advance in the preparation of nanomaterials that can be adapted to ink-printing supercapacitors or other energy storage devices.

Abstract

Manganese dioxide (MnO₂) has been extensively investigated as an electrode material for supercapacitors because of its high theoretical capacitance, great abundance, and low toxicity. To obtain satisfactory capacitance performance, in recent years, many efforts have been dedicated to the fabrication of MnO₂ nanoparticles that offer a larger specific surface area and an escalated chemical activity. Beyond them, the ideal dispersibility of nanoparticles in a liquid medium is also of vital importance when processing those powdery materials into slurry ones for some particular uses, such as editable and ink-printing supercapacitor devices. In this study, the as-synthesized ultrafine MnO₂ nanoparticles having excellent dispersibility in water can be prepared via a facile one-step hydrothermal route, with a uniform size in diameter of 200 nm exhibiting a large specific surface area of ~389.7 m² g⁻¹, and a high specific capacitance of 135.7 F g⁻¹ at 5 mV s⁻¹.

The cover picture illustrates how the form of the copper species deposited on the surface of MCM-41 nanospheres influences the catalytic activity of the obtained catalysts. The original SEM image of silica spheres was used as the background. In the upper left part, a drawing of the MCM-41 channels containing an organic template is presented. On the right side of the figure, an enlargement of MCM-41 channel is shown and also illustrated the procedure of template ion-exchange (TIE). Deposition of various copper phases using TIE was possible. Cu²⁺ are more active in the NO_x conversion, while CuO effectively oxidizes NH₃ - bottom of the picture. More information can be found in the Research Article by Aleksandra Jankowska, and Lucjan Chmielarz et al.

Silver nanoparticle-loaded SERS glass substrates prepared through static thermal evaporation technique showed promise towards easy label-free SERS fingerprinting of lung cancer cells A549 and fibroblast WI-38 cells. Though acquired spectral information revealed minor differences in the Raman fingerprints of specific biomolecules, the supervised linear discriminant analysis could discriminate malignant from healthy cells to a better extent.

Abstract

Lung cancer ranks first for cancer-related mortalities primarily due to late diagnosis. Though Surface-Enhanced Raman spectroscopy (SERS) is a popular bioanalytical technique, its direct application to diagnosis is impeded by low data reproducibility. Colloidal nanoparticles suffer from SERS intensity fluctuations due to unavoidable aggregation, and Brownian and diffusion motions in biological samples. The processes for solid-state SERS substrates are either sophisticated or difficult to reproduce. Herein, we revisit the well-established thermal evaporation process for the easy and reproducible preparation of silver nanoparticles loaded SERS glass substrates. The static mode of thermal evaporation yielded closely packed and uniformly distributed silver nanoparticles. The properties of these nanoparticles are tuned for the best performance by controlling the thermal evaporation process. And SERS substrate exhibited a reasonably good enhancement factor of ~10⁵ with uniformity and reproducibility <6 % RSD over a large area. It was utilized for label-free SERS fingerprinting of lung adenocarcinoma cells A549 and normal lung fibroblast cells, WI-38. The obtained data shows a slight distinction of Raman fingerprints in terms of certain biomolecules like nucleic acids, proteins, and lipids. Further multivariate statistical tools have been utilized which ensures a clear divergence between the cancerous cells and normal cells.