Photocurable Polyurethane\nAcrylated Composites with\nIonic Liquid-Laden Metal–Organic Framework for Energy Storage\nand Electronic Applications

Polymer composites are suitable strategies for the development\nof advanced materials with tailored electrical properties, particularly\nrelevant in electronics areas such as sensors, actuators, and solid\nelectrolytes for energy storage applications. In this study, composites\nbased on a polyurethane acrylated (PUA) matrix with metal–organic\nframework (MOF) nanoparticles (MOF-808) were prepared. Different amounts\nof the ionic liquid 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN])\nwere incorporated into the pores of the MOF-808 structure to tune\nthe electrical response of the composite. The composites PUA/MOF/IL\nunderwent characterization through electron microscopy for morphology\nanalysis, X-ray diffraction (XRS) and Fourier transform infrared spectroscopy\n(FTIR) for the determination of the physical–chemical properties,\nand broadband dielectric spectroscopy (DRS) for assessing dielectric\nand conductive behavior. At the nanoscale, it is shown that when IL\nis infused into the MOF nanoparticles, the MOF pores saturate and\nthe remaining IL stabilizes as an interphase on the surface of the\nMOF particles. DRS reveals that the main α-relaxation of the\nPUA chains is affected by the presence of MOFs and IL, while the secondary\nβ-relaxation, related to local fluctuations, remains unchanged.\nFurthermore, the conductivity process is dependent on the MOF:IL weight\nratio, and the MOF saturation by IL impacts the dielectric behavior\nof the nanocomposites. This study provides valuable nanoscale insights\ninto the interaction between MOF and IL and the dielectric behavior\nof PUA/MOF/IL composites, emphasizing the impact of MOF and IL additives\non the relaxation processes and, in particular, on the electrical\nconductivity. The electrical properties of the developed materials\nshow significant potential for their use as solid polymer electrolytes.