Phonon-Induced Ratchet Motion of a Water Nanodroplet on a Supported Black Phosphorene

Toward Surface Passivation of Black Phosphorus via a Self-Assembled Ferrocene Molecular Layer

Black phosphorus (BP), a promising two-dimensional material, faces significant challenges for its applications due to its instability in air and water. Herein, molecular dynamics simulations reveal that a self-assembled ferrocene (FeCp2) molecular layer can form on BP surfaces and remain stable in aqueous environments, predicting its effectiveness for passivation. This theoretical finding is corroborated by X-ray photoelectron spectroscopy, Fourier-transform infrared spectroscopy, Raman spectroscopy, and optical microscopy observations. In addition, atomic force microscopy analysis confirms that ferrocene-passivated BP flakes with thicknesses of <10 nm exhibit minimal degradation over 25 days. Density functional theory calculations further show that ferrocene stabilizes BP and modulates its band gap, improving its electronic applicability. Notably, we find that the passivation of BP by metallocenes is universal because other metallocenes (VCp2, MnCp2, and NiCp2) exhibit similar adsorption behaviors. These findings underscore the potential of metallocenes as versatile protective layers for BP and other materials that are not stable in air.

Thermal transport properties of gas-filled silica aerogels

Silica aerogel (SA), recognized as an efficient insulating material, is characterized by its extremely low thermal conductivity (TC) and high porosity, presenting extensive application potential in aerospace and building energy conservation. In this study, the thermal transport properties of gas-filled SA are explored using molecular dynamics (MD) methods. It is found that an increase in porosity leads to a significant decrease in TC, primarily due to enhanced phonon scattering and reduced material stiffness. Additionally, the TC of SA influenced by gas exhibits a pattern of initial decrease, followed by an increase, and then a decrease again, driven by complex interactions between gas molecules and pore walls, phonon localization, and scattering mechanisms. At a gas concentration of 80%, the TC in confined spaces is significantly increased by nitrogen, attributed to enhanced intermolecular interactions and increased collision frequency. The impact of gases on the TC of gas-solid coupled composite materials is also investigated, revealing that gas molecules serve as a "bridge" for phonons, playing a crucial role in reducing interfacial scattering and enhancing low-frequency vibrational modes, thus further enhancing heat transfer efficiency. The TC of these composite materials is primarily regulated by the gas-phase TC in response to temperature, while the response to strain is predominantly governed by variations in the solid-phase TC. These results provide essential theoretical support and design guidelines for the development and design of new high-efficiency insulating materials.

Engineering Radioactive Microspheres for Intra‐Arterial Brachytherapy Using Radiation‐Induced Graft Polymerization

Intravascular brachytherapy requires advances in radio‐embolization technologies that combine brilliant radiostability efficacy with a facile and green synthesis route. A hybrid‐integrated radioactive microsphere strategy using phosphorylcholine‐modified lutetium‐177 coordinated polymeric microspheres (177Lu‐PCMs) is reported that are fabricated via radiation‐induced graft polymerization for imaging‐guided locoregional intravascular brachytherapy. The underlying formation mechanism of 177Lu‐PCMs is elucidated using first‐principles computations and density functional theory calculations, and 177Lu loading mechanisms are investigated with Near‐edge and extended X‐ray absorption fine structure spectroscopy. The engineered 177Lu‐PCMs exhibit excellent mechanical properties, good hydrophilicity, and controlled sphere diameter. These features provide advantages of ultra‐stable embolic radio‐theranostics, which is demonstrated in different preclinical rodent models and isolated human liver tumor tissues. During locoregional intra‐arterial brachytherapy, 177Lu‐PCMs can be visualized via SPECT to validate the in vivo biodistribution and retention in real time, achieving precise delivery, effective anti‐cancer treatment, and a distinguished safety profile without degradation, ectopic embolization, and adverse reactions. Therefore, this study offer a new avenue for the development of a highly innovative and translational approach for precision intra‐arterial brachytherapy.

Adjustable diffusion enhancement of water molecules in a nanoscale water bridge

The emergence of nanofluidics in the last few decades has led to the development of various applications such as water desalination, ultrafiltration, osmotic energy conversion, etc. In particular, understanding water molecule transport in nanotubes is of importance for designing novel ultrafiltration and filtering devices. In this paper, we use an electric field to form a nanoscale water bridge as an artificial water channel to connect two separate disjoint nanotubes by molecular dynamics simulations. The extended length of the water bridge under different electric field strengths could adjust the diffusion process of the water molecules crossing the two disjoint nanotubes and the diffusion coefficients could be remarkably enhanced up to 4 times larger than the value in bulk water. By analyzing the structure of the water bridge, it is found that the diffusion enhancement originates from the strengthened interactions and the increase of hydrogen bonds between the water molecules due to the restrained reorientation from the external electric field. Our result provides a promising insight for realizing an efficient mass transport between various disjoint nanochannels.