Recyclable amphiphilic porous thin-films as electrodes for high-performance potassium-ion transport and storage

Recyclable amphiphilic porous thin-films: assembled from nanofibrillated celluloses and reduced graphene oxide via van der Waals interactions, they enable high electrochemical performance of potassium-ion transport and storage.

The Effects of Functional Groups and Missing Linkers on the Adsorption Capacity of Aromatic Hydrocarbons in UiO-66 Thin Films

The adsorption of benzene, toluene, ethylbenzene, and xylene isomers, also known as BTEX, from the gas phase into porous thin films of the metal–organic framework UiO-66-X, where X = H, NH2, and NO2, was measured to quantify adsorption capacity. The thin films were grown by a vapor-conversion method onto Au-coated quartz microbalance crystals. The MOF thin films were characterized by IR and Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy and scanning electron microscopy. The thin films were activated by heating under high vacuum and exposed to each gas to calculate the Henry’s constant. The results demonstrate that the functional groups in the organic linker and missing-linkers both play important roles in the adsorption capacity. Several trends can be observed in the data. First, all the compounds in the BTEX family have lower Henry’s constants in the UiO-66-H films compared to the UiO-66-NH2 and UiO-66-NO2 films, which can largely be attributed to the absence of a functional group on the linker. Second, at 25 °C, the Henry’s constants for all the BTEX compounds in UiO-66-NO2 films are larger than UiO-66-NH2 films. Third, the role of missing linkers is addressed by comparing the measured adsorption capacity to ideal pore filling. The results show that the UiO-66-H films are the most defect-free and the UiO-66-NO2 films have the most missing linker defects.

Combined Modeling of the Optical Anisotropy of Porous Thin Films

In this article, a combined approach for studying the optical anisotropy of porous thin films obtained by the glancing angle deposition is presented. This approach combines modeling on the atomistic and continuum levels. First, thin films clusters are obtained using the full-atomistic molecular dynamics simulation of the deposition process. Then, these clusters are represented as a medium with anisotropic pores, the shapes parameters of which are determined using the Monte Carlo based method. The difference in the main components of the refractive index is calculated in the framework of the anisotropic Bruggeman effective medium theory. The presented approach is tested and validated by comparing the analytical and simulation results for the model problems, and then is applied to silicon dioxide thin films. It is found that the maximum difference between the main components of the refractive index is 0.035 in a film deposited at an angle of 80°. The simulation results agree with the experimental data reported in the literature.