With particle sizes down to the nanoscale, nanometal−organic frameworks (NMOFs) with well-controllable dimensions exhibit many potential applications in drug delivery, biosensing, and biomedical imaging. Although the microemulsion method provides an efficient approach for preparing nanoparticles, the synthesis of NMOFs with narrow size distribution is a great challenge. In this work, nanoscale zeolitic imidazolate frameworks (NZIFs), considered as a subclass of MOFs, were synthesized by the ionic liquid-containing microemulsion system of H 2 O/BmimPF 6 / TX-100. The obtained NZIFs have extremely small size of no more than 2.3 nm, narrow distribution of less than 0.5 nm, and good thermal stabilities. By addition of ethanol into the H 2 O/BmimPF 6 / TX-100 system, [Cu 3 (BTC) 2 (H 2 O) 3 ] n (HKUST-1) was successfully synthesized with nanodimensions similar to those of NZIFs. The molecule dynamic simulation reveals that one new microemulsion was formed in which the ethanol and water molecules were capsuled by the surfactant TX-100 and BmimPF 6 . This new microemulsion is beneficial to the dissolution of organic ligand 1,3,5benzenetricarboxylic acid. This work hopefully provides new insights into the green production of nanoscale MOFs.

Understanding the self-assembly mechanisms of amphiphilic molecules in solutions and regulating their phase behaviors are of primary significance for their applications. To challenge the reported direct phase transitions from nonlamellar to ordered lamellar phases, the self-assembly and phase behavior of the 1-hexadecyl-3methylimidazolium chloride aqueous dispersions were studied using a strategy of isothermal incubation after the temperature jump. A disordered lamellar phase (identified as the lamellar liquid-crystal (L α ) phase), serving as an intermediate, was found to bridge the transition from a spherical micellar (M) phase to a lamellar-gel (L β ) phase. Meanwhile, the nonsynchronicity in the tail and headgroup regions of the ionic liquid surfactant during the transition process was also unveiled, with the former being prior to the latter. The in-depth understanding of the self-assembly mechanisms may help push forward the related applications in the future.

Among various applications, ionic liquids (ILs) have been used as antimicrobial agents in laboratories, possibly through induction of the leakage of bacteria. A molecular-level understanding of the mechanism that describes how ILs enhance the permeation of membranes is still lacking. In this study, the effects of imidazolium-based ILs with different alky chain lengths on the structure and phase behavior of 1-palmitoyl-2-oleoyl-phosphatidylethanolamine (POPE), which is a representative bacteria-membrane-rich lipid, have been investigated. By employing differential scanning calorimetry and synchrotron small-and wide-angle X-ray scattering techniques, we found that ILs with longer alkyl chains influenced the phase behavior more effectively, and lower IL concentrations are needed to induce phase separation for both lamellar liquid crystalline phase and nonlamellar inverted hexagonal phase of POPE. Interestingly, the IL with an alkyl chain of 12 carbon atoms ([C 12 mim]Cl) shows a difference. It exhibits a stronger disturbing effect on the POPE bilayer structure than [C 16 mim]Cl, indicating that the ability of ILs to influence the membrane structures is dependent not only on the alkyl chain length of ILs, but also on the degree of matching of the alkyl chain lengths of ILs and lipids. The new lamellar and nonlamellar structures induced by ILs both have smaller repeat distances than that of pure POPE, implying thinner membrane structures. Data of the fluorescence-based vesicle dye leakage assay are consistent with these results, particularly the defects caused by IL-induced phase separation can enhance the membrane permeability markedly. The present work may shed light on our understanding of the antimicrobial mechanism of ILs.

Ionic liquids (ILs), although being a class of promising green solvents, have received many reports on the toxicity to living organisms. In this work, aiming at elucidating the disruptive effect of ILs to cell membrane lipid rafts, we investigated the effect of three 1-octylimidazolium-based ILs on the properties of the liquid ordered phase (L o , a commonly used lipid raft model) of egg sphingomyelin (SM)-cholesterol model membrane. We found that, in the absence of cholesterol, a very low IL:SM molar ratio of 0.01:1 could disrupt the integrity of the bilayer structure. In sharp contrast, the presence of cholesterol in lipid bilayers helps the L o phase resist the damaging effect of the ILs. For the role of the IL headgroup, we found that the mono-and trisubstituted species show a stronger destructive effect on the structures of the model rafts than the commonly used disubstituted counterpart.