Nozari Vahid, Azar Ayda Nemati Vesali, Sajzew Roman, Castillo-Blas Celia, Kono Ayano, Oschatz Martin, Keen David A, Chater Philip A, Robertson Georgina P, Steele James M A, León-Alcaide Luis, Knebel Alexander, Ashling Christopher W, Bennett Thomas D, Wondraczek Lothar
Otto Schott Institute of Materials Research, University of Jena, 07743, Jena, Germany.
Department of Materials Science and Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge, CB30FS, UK.
Small. 2024 Oct;20(43):e2303315. doi: 10.1002/smll.202303315. Epub 2024 Jul 26.
Metal-organic framework (MOF) composite materials containing ionic liquids (ILs) have been proposed for a range of potential applications, including gas separation, ion conduction, and hybrid glass formation. Here, an order transition in an IL@MOF composite is discovered using CuBTC (copper benzene-1,3,5-tricarboxylate) and [EMIM][TFSI] (1-ethyl-3-methylimidazolium bis(trifluoromethanesulfonyl)imide). This transition - absent for the bare MOF or IL - provides an extended super-cooling range and latent heat at a capacity similar to that of soft paraffins, in the temperature range of ≈220 °C. Structural analysis and in situ monitoring indicate an electrostatic interaction between the IL molecules and the Cu paddle-wheels, leading to a decrease in pore symmetry at low temperature. These interactions are reversibly released above the transition temperature, which reflects in a volume expansion of the MOF-IL composite.
含有离子液体（ILs）的金属有机框架（MOF）复合材料已被提出用于一系列潜在应用，包括气体分离、离子传导和混合玻璃形成。在此，使用CuBTC（铜苯-1,3,5-三羧酸盐）和[EMIM][TFSI]（1-乙基-3-甲基咪唑鎓双（三氟甲磺酰）亚胺）发现了IL@MOF复合材料中的有序转变。这种转变在裸MOF或IL中不存在，在约220°C的温度范围内提供了与软石蜡相似的扩展过冷范围和潜热。结构分析和原位监测表明IL分子与铜桨轮之间存在静电相互作用，导致低温下孔对称性降低。这些相互作用在转变温度以上可逆释放，这反映在MOF-IL复合材料的体积膨胀上。
