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We report the ionothermal carbonization (ITC) of lignocellulosic biomass in imidazolium tetrachloroferrate ionic liquids (ILs) as an advantageous approach for the preparation of nanostructured carbonaceous materials, namely, ionochars. In a previous study, we investigated the role of the imidazolium cation and demonstrated the possibility of controlling both the textural and morphological properties of ionochars by cation engineering. Although essential for providing intermediate Lewis acidity and relatively high thermal stability, the role of the chloroferrate anion is still open to debate. Herein, we investigated the ITC of sugarcane bagasse and its main component, cellulose, in 1-alkyl-3-methylimidazolium ILs with different chloroferrate anions. We identified anionic speciation and its impact on the properties of the IL by Raman spectroscopy, thermogravimetric analysis, and differential scanning calorimetry. The obtained ionochars were characterized by gas physisorption, electron microscopy, Raman spectroscopy, Fourier transform infrared (FTIR) spectroscopy, and 13 C solid-state CP-MAS NMR spectroscopy. We show that the anionic species have a predominant impact on the textural and morphological properties of the ionochars.

The properties of carbon, boron nitride, silicon, germanium, and molybdenum disulfide nanotubes in reline (cholinium chloride + urea) deep eutectic solvents were studied by using classical molecular dynamics simulations. These nanotubes + reline nanofluids provide a suitable platform for the development of sustainable thermal engineering applications. The reported results lead to the characterization of nanotube solvation and reline layering around the nanotube surfaces as well as the behavior of reline upon confinement inside the considered nanotube cavities. Changes in reline hydrogen bonding in the presence of the nanotubes are also analyzed and related with the development of stable nanotube dispersions, thus showing reline as a suitable vehicle for nanotubes.

Molecular dynamics simulations were employed to both estimate the solubility of nonelectrolyte solids, such as acetanilide, acetaminophen, phenacetin, methylparaben, and lidocaine, in supercritical carbon dioxide and understand the underlying molecular-level driving forces. The solubility calculations involve the estimation of the solute's limiting activity coefficient, which may be computed using conventional staged free-energy calculations. For the case of lidocaine, wherein the infinite dilution approximation is not appropriate, we demonstrate how the activity coefficient at finite concentrations may be estimated without additional effort using the dilute solution approximation and how this may be used to further understand the solvation process. Combining with experimental pure-solid properties, namely, the normal melting point and enthalpy of fusion, solubilities were estimated. The results are in good quantitative agreement with available experimental data, suggesting that molecular simulations may be a powerful tool for understanding supercritical processes and the design of carbon dioxide-philic molecular systems. Structural analyses were performed to shed light on the microscopic details of the solvation of different functional groups by carbon dioxide and the observed solubility trends.

During the manufacturing of pharmaceutical compounds, solvent mixtures are commonly used, where the addition of a cosolvent allows for the tuning of the intermolecular interactions present in the system. Here we demonstrate how a similar effect can be accomplished using a room temperature ionic liquid. The pharmaceutical compound acetaminophen is studied in 21 common ionic liquids composed of a 1-n-alkyl-3-methylimidazolium cation with 1 of 7 anions. Using the acetate anion, we predict a large enhancement in solubility of acetaminophen relative to water. We show how this is caused by a synergistic effect of favorable interactions between the ionic liquid and the phenyl, hydroxyl and amide groups of acetaminophen, demonstrating how the ionic liquid cation and anion may be chosen to preferentially solvate different functional groups of complex pharmaceutical compounds. Additionally, while the use of charge scaling in ionic liquid force fields has previously been found to have a minute effect on ionic liquid structural properties, we find it appreciably affects the computed solvation free energy of acetaminophen, which in turn affects the predicted solubility.

Sequentially adsorbed multilayers composed of sodium lignosulfonate (SL) and poly(diallyldimethylammonium chloride) (PDAC) were built up by a layer-by-layer self-assembly technique to investigate the adsorption characteristics of SL microgels for sensitivity improvement. The effect of molecular weight on the adsorption characteristics was investigated by light scattering, UV-visible spectroscopy, ellipsometer, X-ray photoelectron spectroscopy (XPS), atomic force microscopy (AFM), and contact angle measurements. Results show that the self-assembly of SL microgels and PDAC is not mainly driven by electrostatic interaction but by cation-π interaction and hydrophobic interaction. The Coulomb interaction in SL microgels causes a "slow mode" peak in dynamic light scattering measurement, but it can be completely suppressed when SL is dissolved in 1.2 mol/L NaCl solutions due to charge-screening. The SL in 1.2 mol/L NaCl solutions can be well adsorbed on a PDAC surface, indicating that the electrostatic interaction is not the main driving force. The presence of cation-π interaction between SL and PDAC is detected by a stoichiometric ratio of SL to PDAC in SL/PDAC self-assembled films. During SL/PDAC self-assembly, hydrophobic interaction plays an important role in determining the adsorption rate, film thickness, surface morphology, and surface properties. SL with a higher M(w) has a stronger hydrophobic ability in water, so it exhibits a slower adsorption rate, a larger film thickness, and a higher film roughness. SL with different M(w) has almost the same wettability because of a larger hydrophobic effect that increases contact angle and a higher film roughness that decreases contact angle. In this case, the opposite effects cancel each other to make no difference in wettability, but it still reflects the role of the hydrophobic effect in surface properties.

The kinetics of loading of polystyrene197-block-poly(acrylic acid)47 (PS197-b-PAA47) micelles, suspended in water, with thiocyanomethylthiobenzothiazole biocide and its subsequent release were investigated. Loading of the micelles was found to be a two-step process. First, the surface of the PS core of the micelles is saturated with biocide, with a rate determined by the transfer of solid biocide to micelles during transient micelle-biocide contacts. Next, the biocide penetrates as a front into the micelles, lowering the Tg in the process (non-Fickian case II diffusion). The slow rate of release is governed by the height of the energy barrier that a biocide molecule must overcome to pass from PS into water, resulting in a uniform biocide concentration within the micelle, until Tg is increased to the point that diffusion inside the micelles becomes very slow. Maximum loading of biocide into micelles is approximately 30% (w/w) and is achieved in 1 h. From partition experiments, it can be concluded that the biocide has a similar preference for polystyrene as for ethylbenzene over water, implying that the maximum loading is governed by thermodynamics.

A careful conformational analysis of poly(styrene-alt-maleic anhydride) at different pH values is presented. It is found that a strong internal hydrogen bond is formed at intermediate pH, which induces a change in the conformation of the polymer chain, which becomes linear. This linearity does not depend on the chirality of the polymer. The linearity of the chain occurs only at intermediate pH and can explain the association among the chains observed by dynamic light scattering at pH 7.