Controlled hydrothermal synthesis of Ag nanowires and their antimicrobial properties

Scale-up construction of stable multifunctional hydrogel interfaces for large-scale purification of complex oil-water emulsions and oil recovery

Inspired by the multi-level structure of grass clumps in nature, a novel filter with plexiform-structured hydrogel interface was constructed using sepiolite-derived silica nanofiber (SiNF) as the supporter and crosslinked polyvinyl alcohol (cl-PVA) hydrogel as the coating. Experimental test, DFT and MD calculations have confirmed that the addition of SiNF can not only enhance oil-water separation efficiency, but also improve the stability of hydrogel coating. The hydrogel interface with excellent stability and superhydrophilic/underwater superoleophobicity can be manufactured on a large copper mesh (1 m × 1.2 m) to achieve large-scale production. The surface-engineered mesh (named cl-PVA/SiNF@Ag-Cu) can be assembled on a self-designed equipment for continuous purification of emulsion wastewater (processing capacity: 576.00 L/day), achieving a high separation efficiency of 99.7 % for complex oily emulsion only under the action of gravity, and can simultaneously recover oils. After being treated under extreme conditions such as strong acid/alkali, high/low temperature (100 °C, 200 °C, and -18 °C), high salt concentration, sandpaper wear, and long-term aging, the surface structure of cl-PVA/SiNF@Ag-Cu filter remains stable. The antifouling, antibacterial, and anticorrosion capabilities of the filter give it the potential for long-term and large-scale purification processes. Planting and breeding experiments have confirmed that purified water is harmless to animals and plants.

Synergistic role of Cl- and Br- ions in growth control and mechanistic insights of high aspect ratio silver nanowires for flexible transparent conductive films

Silver nanowires (AgNWs) with high aspect ratios are pivotal for the production of flexible transparent conductive films (TCFs). The growth of AgNWs is significantly influenced by the strong affinity of halogen ions for silver ions. This affinity plays a crucial role in the controlled deposition of silver along the nanowire axis. By precisely controlling the concentrations of Cl- and Br- ions, we have successfully synthesized AgNWs with remarkable lengths of 96 μm and diameters of 40 nm, achieving an impressive aspect ratio of 2400. Utilizing density functional theory and molecular dynamics simulations, we investigate the impact of these ions on the growth of AgNWs. Our findings reveal that halogen ions strongly adsorb onto the Ag (100) plane in the radial direction, with Cl- ions promoting anisotropic growth and Br- ions effectively limiting the nanowire diameter, thus achieving high aspect ratio AgNWs. The resulting TCFs exhibit a high transmittance of 95.0% at 550 nm and a low sheet resistance of 14.7 Ω sq-1. Moreover, when integrated into a flexible transparent heater, these TCFs demonstrate a high heating rate of 12.1 °C s-1. The development of AgNWs is poised to significantly enhance the performance and versatility of flexible TCFs.

Silver Nanoparticles: Synthesis, Structure, Properties and Applications

Silver nanoparticles (Ag NPs) have accumulated significant interest due to their exceptional physicochemical properties and remarkable applications in biomedicine, electronics, and catalysis sensing. This comprehensive review provides an in-depth study of synthetic approaches such as biological synthesis, chemical synthesis, and physical synthesis with a detailed overview of their sub-methodologies, highlighting advantages and disadvantages. Additionally, structural properties affected by synthesis methods are discussed in detail by examining the dimensions and surface morphology. The review explores the distinctive properties of Ag NPs, including optical, electrical, catalytic, and antimicrobial properties, which render them beneficial for a range of applications. Furthermore, this review describes the diverse applications in several fields, such as medicine, environmental science, electronics, and optoelectronics. However, with numerous applications, several kinds of issues still exist. Future attempts need to address difficulties regarding synthetic techniques, environmental friendliness, and affordability. In order to ensure the secure utilization of Ag NPs, it is necessary to establish sustainability in synthetic techniques and eco-friendly production methods. This review aims to give a comprehensive overview of the synthesis, structural analysis, properties, and multifaceted applications of Ag NPs.

First-principles study of mercaptoundecanoic acid molecule adsorption and gas molecule penetration onto silver surface: an insight for corrosion protection

Recently, 11-mercaptoundecanoic acid (MUA) molecule has attracted attention as a promising passivation agent of Ag nanowire (NW) network electrode for corrosion inhibition, but the underneath mechanism has not been elaborated. In this work, we investigate adsorption of MUA molecule on Ag(1 0 0) and Ag(1 1 1) surface, adsorption of air gas molecules of H2O, H2S and O2 on MUA molecular end surface, and their penetrations into the Ag surface using the first-principles calculations. Our calculations reveal that the MUA molecule is strongly bound to the Ag surface with the binding energies ranging from -0.47 to -2.06 eV and the Ag-S bond lengths of 2.68-2.97 Å by Lewis acid-base reaction. Furthermore, we find attractive interactions between the gas molecules and the MUA@Ag complexes upon their adsorptions and calculate activation barriers for their migrations from the outermost end of the complexes to the top of Ag surface. It is found that the penetrations of H2O and H2S are more difficult than the O2 penetration due to their higher activation barriers, while the O2 penetration is still difficult, confirming the corrosion protection of Ag NW network by adsorbing the uniform monolayer of MUA. With these findings, this work can contribute to finding a better passivation agent in the strategy of corrosion protection of Ag NW network electrode.

Quantitative Analysis of Acetone in Transformer Oil Based on ZnO NPs@Ag NWs SERS Substrates Combined with a Stoichiometric Model

Acetone is an essential indicator for determining the aging of transformer insulation. Rapid, sensitive, and accurate quantification of acetone in transformer oil is highly significant in assessing the aging of oil-paper insulation systems. In this study, silver nanowires modified with small zinc oxide nanoparticles (ZnO NPs@Ag NWs) were excellent surface-enhanced Raman scattering (SERS) substrates and efficiently and sensitively detected acetone in transformer oil. Stoichiometric models such as multiple linear regression (MLR) models and partial least square regressions (PLS) were investigated to quantify acetone in transformer oil and compared with commonly used univariate linear regressions (ULR). PLS combined with a preprocessing algorithm provided the best prediction model, with a correlation coefficient of 0.998251 for the calibration set, 0.997678 for the predictive set, a root mean square error in the calibration set (RMSECV = 0.12596 mg/g), and a prediction set (RMSEP = 0.11408 mg/g). For an acetone solution of 0.003 mg/g, the mean absolute percentage error (MAPE) was the lowest among the three quantitative models. For a concentration of 7.29 mg/g, the MAPE was 1.60%. This method achieved limits of quantification and detections of 0.003 mg/g and 1 μg/g, respectively. In general, these results suggested that ZnO NPs@Ag NWs as SERS substrates coupled with PLS simply and accurately quantified trace acetone concentrations in transformer oil.