RESUMEN
Although numerous polymer-based composites exhibit excellent dielectric permittivity, their dielectric performance in various applications is severely hampered by high dielectric loss induced by interfacial space charging and a leakage current. Herein, we demonstrate that embedding molten salt etched MXene into a poly(vinylidene fluoride-trifluoroethylene-chlorofluoroethylene) (P(VDF-TrFE-CFE))/poly(methyl methacrylate) (PMMA) hybrid matrix induces strong interfacial interactions, forming a close-packed inner polymer layer and leading to significantly suppressed dielectric loss and markedly increased dielectric permittivity over a broad frequency range. The intensive molecular interaction caused by the dense electronegative functional terminations (-O and -Cl) in MXene results in restricted polymer chain movement and dense molecular arrangement, which reduce the transportation of the mobile charge carriers. Consequently, compared to the neat polymer, the dielectric constant of the composite with 2.8 wt % MXene filler increases from â¼52 to â¼180 and the dielectric loss remains at the same value (â¼0.06) at 1 kHz. We demonstrate that the dielectric loss suppression is largely due to the formation of close-packed interfaces between the MXene and the polymer matrix.
RESUMEN
[This corrects the article DOI: 10.1039/D2SC06699H.].
RESUMEN
The modern technology for acetylene production is inevitably accompanied by the contamination of carbon dioxide and moisture impurities. Metal-organic frameworks (MOFs), with rational configurations of fluorine as the hydrogen-bonding acceptor (HBA), exhibit excellent affinities to capture acetylene from the gas mixtures. Currently, most research studies feature anionic fluorine groups as structural pillars (e.g., SiF6 2-, TiF6 2-, NbOF5 2-), whereas in situ insertion of fluorine into metal clusters is rather challenging. Herein, we report a unique fluorine-bridged Fe-MOF, i.e., DNL-9(Fe), which is assembled by mixed-valence FeIIFeIII clusters and renewable organic ligands. The fluorine species in the coordination-saturated structure offer superior C2H2-favored adsorption sites facilitated by hydrogen bonding, with a lower C2H2 adsorption enthalpy than other reported HBA-MOFs, demonstrated by static/dynamic adsorption tests and theoretical calculations. Importantly, DNL-9(Fe) shows exceptional hydrochemical stability under aqueous, acidic, and basic conditions, and its intriguing performance for C2H2/CO2 separation was even maintained at a high relative humidity of 90%.