A custom-made rotational coating system that can apply constant, uniform, and high force to nanosheets was made. Montmorillonite (MMT) nanosheets and polyvinyl alcohol (PVA) chains were coassembled onto a poly(ethylene terephthalate) (PET) substrate using a rotational coating process. Different concentrations and centripetal accelerations were explored to study their effects on coating properties. The nanocoating thickness was determined by a thin-film measurement system and a stylus profilometer. The turbidity of the coating layer was determined using ultraviolet–visible (UV–Vis) spectrophotometry and the Beer-Lambert law. The nanostructure of the coating was characterized by X-ray diffraction (XRD). Finally, the oxygen transmission rate was measured to determine the effects of processing conditions on permeability. Two statistical approaches were used to determine the degree to which each processing parameter has an impact on each coating property. Aside from the fundamental study on rotational coating, this coating technique can fabricate highly ordered nanocoatings with significantly improved barrier properties. Potential applications are envisioned in the fabrication of food packages, dielectric materials, and biomedical devices.

Polyvinyl alcohol (PVA)/laponite (LP) nanocomposite coatings were fabricated via a facile one-step coassembly process. The formed nanocoatings contain a high concentration of LP nanosheets, which can be well aligned along the substrate surface during the coassembly process. Due to the highly orientated structure, the flexible nanocoatings exhibit ultra-high transparency and superior mechanical properties, and can also act as excellent gas barriers. Such nanocoatings can be exceptional candidates for a variety of applications, such as food packaging.

Nanocoatings In article number 2101374, Yang Cao, Luyi Sun, and co-workers present a layered nanocoating comprising hundreds of highly oriented organic/inorganic alternating nanolayers on the polymer surface to revive the Schottky barrier for effective charge-injection blocking. The superior 2D assembly leads to a flexible material architecture at the electrode–dielectric interface, thus providing a novel design strategy for high-performance dielectrics for integrated flexible electronics.

The organic insulator–metal interface is the most important junction in flexible electronics. The strong band offset of organic insulators over the Fermi level of electrodes should theoretically impart a sufficient impediment for charge injection known as the Schottky barrier. However, defect formation through Anderson localization due to topological disorder in polymers leads to reduced barriers and hence cumbersome devices. A facile nanocoating comprising hundreds of highly oriented organic/inorganic alternating nanolayers is self‐coassembled on the surface of polymer films to revive the Schottky barrier. Carrier injection over the enhanced barrier is further shunted by anisotropic 2D conduction. This new interface engineering strategy allows a significant elevation of the operating field for organic insulators by 45% and a 7× improvement in discharge efficiency for Kapton at 150 °C. This superior 2D nanocoating thus provides a defect‐tolerant approach for effective reviving of the Schottky barrier, one century after its discovery, broadly applicable for flexible electronics.

The popular use of silver nanoparticles (Ag NPs) in commercial textile products that inhibit odor- and/or infection-causing bacteria has continuously raised concerns about their washing durability. The poor durability not only deteriorates the antibacterial performance, but also results in unwanted leaching of NPs into washing solutions. In this study, we showed how the incorporation location of Ag NPs—interior vs. exterior of cotton fiber—governs their durability against consecutive simulated home launderings. The superior washing durability of interior NPs was confirmed. The Ag losses after 50 laundering cycles for interior and exterior systems were 16% and 63% in water and 24% and 78% in detergent solution, respectively. The cotton fabric containing interior NPs predominantly released ionic Ag, whereas the fabric containing exterior NPs released particulate Ag.

Inspired by hook-and-loop fasteners, we designed a hydrogel network containing α-zirconium phosphate (ZrP) two-dimensional nanosheets with a high density of surface hydroxyl groups serving as nanopatches with numerous "hooks," while polymer chains with plentiful amine functional groups serve as "loops." Our multiscale molecular simulations confirm that both the high density of hydroxyl groups on nanosheets and the large number of amine functional groups on polymer chains are essential to achieve reversible interactions at the molecular scale, functioning as nano hook-and-loop fasteners to dissipate energy. As a result, the synthesized hydrogel possesses superior stretchability (>2100% strain), resilience to compression (>90% strain), and durability. Remarkably, the hydrogel can sustain >5000 cycles of compression with torsion in a solution mimicking synovial fluid, thus promising for potential biomedical applications such as artificial articular cartilage. This hook-and-loop model can be adopted and generalized to design a wide range of multifunctional materials with exceptional mechanical properties.

Plastics films have been widely used in food packaging.But due to the environmental concerns of plastics films, there is a trend of replacing plastics films with paper for food packaging.To meet the requirements of packaging, the paper must be modified to improve its barrier properties.In this report, a sonication and dip coating method was developed to deposit a polyvinyl alcohol (PVA)/montmorillonite (MMT) nanocoating on two representative paper substrates: regular paper and cotton paper.The coated paper substrates were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), water vapor transmission rate (WVTR), and microscale combustion calorimetry (MCC).The XRD results support the formation of well-aligned MMT nanosheets on paper substrates, and the SEM images show that most pores on the substrates were covered by the nanocoatings, which leads to a drastic decrease in WVTR of the coated substrates.The nanocoatings also led to a minor improvement in flame retardancy.The results suggest that applying nanocoating is a promising approach to improving the barrier properties of paper for potential packaging applications.

The popular use of silver nanoparticles (Ag NPs) in the production of commercial odor-control and antibacterial textile products has raised questions about their washing durability. Poor durability not only deteriorates product performance but also results in unknown amounts of Ag NPs leaching into sewage- and water-treatment systems. Therefore, it is necessary to have a quick and easy method for detecting Ag NPs in washing solutions for assessment of washing durability. In this study, we have developed a practical surface-enhanced Raman spectroscopy (SERS) method for measuring the concentrations of Ag NPs in water and a detergent solution. To improve the sensitivity and reproducibility of SERS signals from the complexation of an indicator molecule (ferric dimethyl-dithiocarbamate, in this study) with NPs, the "coffee ring effect" was utilized. The active SERS "hot spots" in the aggregated NPs along the coffee ring effectively intensified the signature SERS response, even with NPs of about 10 nm in diameter and a concentration as low as 0.01 mg L-1. The linear relationships between SERS intensity and Ag NP concentration (R-2 > 0.99) successfully quantified the amount of Ag NPs released from Ag NP-treated cotton fabrics during washing as well as other Ag speciation formed in a detergent solution.

A highly stable clay-based membrane was designed and fabricated that can be used for both salinity gradient energy conversion and organic dye/water separation.