Effect of Water Immersion on Raw and Expanded Ugandan Vermiculite

Effect of water immersion at different times (from 1/2h to 24 h) on raw and expanded vermiculite from Uganda was investigated. The expansion was carried out by electrical heating at different temperatures and by irradiation with microwaves. After, the expansibility (k) and the water absorption content (WA) were obtained and the samples were characterized. The elemental and mineral composition was determined by X-ray fluorescence and X-ray diffraction, respectively; the thermal behavior by thermal gravimetric analyses; and the textural parameters by BET. The expansibility of Ugandan vermiculite is relatively lower than the other commercial vermiculites due basically to its lower K2O content (0.36%) and higher water content (about 20%). The water absorption capacity of samples significantly increased with the increase in heating temperature. The maximum WA content, about 130 mg/g, was obtained at 900 °C for 24 h. The loss of water during the expansion process in the Ugandan vermiculite caused loss of structural order and crystallinity. Moreover, in the samples expanded and subsequently immersed in water, the structural order and crystallinity increased with increasing WA values. Specific surface area and porosity hardly vary with temperature and are practically independent of vermiculite purity. Expanded commercial vermiculites could be a suitable hygroscopic material, given its efficient water absorption. Microwave expanded commercial vermiculites, in this case, would not be recommended

Solvent vapor annealing for controlled pore expansion of block copolymer-assembled inorganic mesoporous films

Mesoporous inorganic thin films are promising materials architectures for a variety of high-value applications, ranging from optical coatings and purification membranes to sensing and energy storage devices. Having precise control over the structural parameters of the porous network is crucial for expanding their applicability. To this end, the use of block copolymers (BCP) as sacrificial structure-directing agents via micelle co-assembly is a particularly attractive route, since the resultant pore size is directly related to scaling laws for the radius of gyration of the pore-forming macromolecule. However, tailoring the molecular weight of the BCP via bespoke synthesis is an elaborate process that requires precise control over highly sensitive reactions conditions. Alternative methods have emerged, based on supramolecular assembly or the addition of different swelling agents, but, to-date, these present a negative impact on the structural order and pore size dispersity of the final inorganic mesoporous films. In this work, we propose a novel and effective method for control over pore size, porosity and structural order, which relies on a synergistic combination of BCP selective swelling via solvent vapor annealing (SVA) and locking of the structure by condensation of the inorganic sol-gel precursors. The results obtained in this work for TiO2 establish SVA as a new, straightforward, simple, and powerful route efor the fabrication of mesoporous thin-film materials with controllable structural characteristics.

Prosty język w komunikacji prawniczej – okiem redaktora językowego

The article discusses the practical use of plain language rules in editing law-related texts. The author believes that it is possible and worth the effort to write legal texts in accordance with the rules of plain language, i.e. with the expected reader in mind, giving examples of rewritten sentences taken from the articles for an online law portal. The author divides the processes in terms of ‘structural order’ and ‘linguistic order’ and shows that even cosmetic editing in the spirit of plain language, without affecting the text’s structure, improves its intelligibility.