Thermodynamic Modeling of Solvent-Assisted Lipid Bilayer Formation Process

The solvent-assisted lipid bilayer (SALB) formation method provides a simple and efficient, microfluidic-based strategy to fabricate supported lipid bilayers (SLBs) with rich compositional diversity on a wide range of solid supports. While various studies have been performed to characterize SLBs formed using the SALB method, relatively limited work has been carried out to understand the underlying mechanisms of SALB formation under various experimental conditions. Through thermodynamic modeling, we studied the experimental parameters that affect the SALB formation process, including substrate surface properties, initial lipid concentration, and temperature. It was found that all the parameters are critically important to successfully form high-quality SLBs. The model also helps to identify the range of parameter space within which conformal, homogeneous SLBs can be fabricated, and provides mechanistic guidance to optimize experimental conditions for lipid membrane-related applications.

Joint Analysis and Reliability Test of Epoxy-Based Nano Silver Paste Under Different Pressure-Less Sintering Processes

Recent years, the sintered silver paste was introduced and further developed for power electronics packaging due to low processing temperature and high working temperature. The pressure-less sintering technology reduces the stress damage caused by the pressure to the chip, improves reliability, and is widely applied in manufacturing. Currently, most existed studies are focused on alcohol-based sintered silver pastes while resins have been demonstrated to improve the bonding properties of solder joints. Hence, the performance and sintering mechanisms with epoxy-based silver paste need to be further explored. In this work, a methodology for multi-factor investigation is settled on the epoxy-based silver paste to reveal the relationship between the strength and the different influence factors. We firstly analyzed the characteristics of commercialized epoxy-based silver paste samples, including silver content, silver particle size, organic paste composition, sample viscosity, and thermal conductivity. Samples were then prepared for shear tests and microstructure analysis under different pressure-less sintering temperatures, holding time, substrate surface, and chip size. Full factor analysis results were further discussed in detail for correlation. The influence factors were ranked from strong to weak as follows: sintering temperature, substrate surface, chip size, and holding time. Finally, a thermal cycling test was carried out for reliability analysis. Epoxy residues are one of the possible reasons which result in shear strength decreasing exponentially.

Laser Fabrication of Titanium Alloy-Based Photothermal Responsive Slippery Surface

In recent years, biomimetic materials inspired from natural organisms have attracted great attention due to their promising functionalities and cutting-edge applications, emerging as an important research topic. For example, how to reduce the reflectivity of the solid surface and increase the absorption of the substrate surface is essential for developing light response smart surface. Suitable solutions to this issue can be found in natural creatures; however, it is technologically challenging. In this work, inspired from butterfly wings, we proposed a laser processing technology to prepare micro nanostructured titanium alloy surfaces with anti-reflection properties. The reflectivity is significantly suppressed, and thus, the light absorption is improved. Consequently, the anti-reflection titanium alloy surface can be further employed as a photothermal substrate for developing light-responsive slippery surface. The sliding behavior of liquid droplets on the smart slippery surface can be well controlled via light irradiation. This method facilitates the preparation of low-reflection and high-absorption metallic surfaces towards bionic applications.

Keeping a Clean Surface under Water: Nanoscale Nipple Array Decreases Surface Adsorption and Adhesion Forces

While nanoscale nipple arrays are expected to reduce light reflection and/or dust contamination in some insects, similar structures have been reported in various marine invertebrates. To evaluate the anti-contamination property of the structure in aquatic regimes, we measured the adsorption and adhesion forces on the flat surface and MOSMITE™ (Mitsubishi Chemical Corporation, Tokyo, Japan), a synthetic material mimicking the nipple array, under water. A small force toward the surface occurred when the probe approached the substrate surface. This adsorption force was significantly smaller on MOSMITE™ than on the flat surface. The adhesion force toward the surface occurred when the probe was detached from the surface, and it was also significantly smaller on MOSMITE™ than on the flat surface. The adhesion force in the air was much greater than the force under water, and the force was also significantly smaller on MOSMITE™ than on the flat surface. In the aquatic regime, the nipple array provides less adsorption/adhesion properties for the surface and thus, the organisms would have less contamination of microparticles on their body surface. As the adsorption and adhesion forces are also involved in the attachment of cells, tissue, and larvae, less adhesive body surfaces should be beneficial for survival in aquatic environments, as well as land environments.

LSPR Sensor Chip Fabricated Based on Au Nanoparticles: Effect of Graphene Oxide and Reduced Graphene Oxide

Nanoparticles of noble metals are well known to display unique optical properties due to the localized surface plasmon resonance (LSPR) phenomenon, making them applicable for use as transducers in various LSPR sensor configurations. In order to develop a sensor chip, Au nanoparticles (AuNPs) were decorated onto a transparent glass substrate in the form of a uniform, high-density single layer using a self-assembly monolayer (SAM) process. The glass substrate surface was initially modified with amine functional groups using different concentrations of (3-Aminopropyl) triethoxysilane (APTES), followed by its optimization to reach a uniform monolayer of AuNPs. The optimized substrate was subsequently prepared by functionalization with APTES, while also being immersed into colloidal AuNPs. A uniform layer of Graphene oxide (GO) and reduced graphene oxide (rGO) sheets were coated on the AuNPs thin films using the dip-coating technique. The AuNPs/GO and rGO hybrid films were employed along with an appropriate optical set up acting as a smart sensor chip for detection of different concentrations of biomaterials. The optimum LSPR sensor (%0.5 APTES immersed in colloidal AuNPs for 12 h) resulted in a chip with %29 absorption and sharper plasmon peak. This appropriate condition remained constant after adding rGO, indicating that Glass/AuNPs/rGO chip will be suitable for sensory applications.

Формирование наноразмерных пленок золота в условиях многократного автооблучения при ионно-лучевом осаждении

Gold films with a thickness of several tens of nanometers were obtained on silicon and quartz substrates by ion-beam deposition – sputtering. It is shown that the predominant lateral growth of nanoscale metal layers along the substrate surface occurs under exposure to the high-energy component of the sputtered atoms flux. The decisive role in the nanometer gold film for-mation is played by the elastic collision of sputtered metal atoms with atoms of the substrate and the growing film. The application of the manifold deposition – sputtering operation allows sup-pressing the grain formation process and obtaining gold films with better characteristics than those with a single deposition.

Асимптотическая стадия роста автокаталитических III-V нитевидных нанокристаллов методом молекулярно-пучковой эпитаксии

A new analytic theory is developed for asymptotic stage of self-catalyzed growth of III-V nanowires (NWs) by molecular beam epitaxy (MBE), where NWs collect all group III atoms deposited from vapor. The shadowing NW length is derived which corresponds for the full shadowing of the substrate surface in MBE. The NW length and radius are derived depending on the effective deposition thickness and MBE growth parameters. It is shown that the NW length increases, and their length decreases with decreasing the array pitch and increasing the V/III flux ratio.

Enhanced Adhesion Strength of Pt/γ-Al2O3 Catalysts on STS-444 Substrate via γ-Al2O3 Intermediate Layer Formation: Application for CO and C3H6 Oxidation

Pt/γ-Al2O3 catalysts coated on honeycomb-shaped stainless STS-444 steel substrates with a γ-Al2O3 intermediate layer were prepared using a conventional washcoating method. The intermediate layer was formed on the substrate surface through oxidation using pack cementation. The monolithic catalysts with the intermediate layer were fabricated for potential applications to pre-turbocharger catalysts, which suffer from severe conditions such as vibrations of the engine and high flow rates of exhaust gas. Adhesive strength tests and simultaneous oxidation reactions of CO and C3H6 were carried out for the Pt/γ-Al2O3 monolithic catalysts with and without the intermediate layer. The catalysts with an intermediate layer showed much stronger adhesion than the catalysts without an intermediate layer. Thus, the formation of a γ-Al2O3 intermediate layer by surface oxidation through pack cementation facilitated a significant enhancement of the catalyst adhesion strength without catalytic performance degradation.