Flexible MWCNT/PVA/Mn Ferrite/AC Metacomposites with Tunable Negative Permittivity for Low-Frequency Reflectors and Optical Sensors

With the development of new metamaterials made of periodic array structures, negative permittivity has recently received more and more attention. However, it is crucial to achieve negative permittivity behavior based on materials’ intrinsic properties rather than their synthetically periodic structures, as easy preparation is always a priority. Wearable cloaks, stretchable sensors, thin-film capacitors, and other applications all hold great promise for flexible metacomposites with tunable negative permittivity. Herein, flexible multi-walled carbon nanotube/poly(vinyl alcohol)/manganese ferrite/active carbon (MWCNT/PVA/Mn ferrite/AC) porous metacomposites with negative dielectric constant were prepared by feasible sol–gel method. The resulting metacomposites with various MWCNT mass values were examined for their ac conductivity behavior, magnetic and dielectric characteristics, impedance, and absorbance performances. The findings indicate that these novel amorphous metacomposites possess exceptional qualities, such as superior impedance matching, magnetic characteristics, exceptional reflectivity, and proficiency as an optical sensor, alongside their negative dielectric constant.