Structure-dynamic properties relationships in poly(ethylene oxide)/silicon dioxide nanocomposites: dielectric relaxation study

Films of polyethylene oxide (PEO) filled with silicon dioxide (SiO2) were synthesized via casting method. The formation of the PEO/SiO(2)nanocomposites was characterized by X-ray diffraction (XRD) and Fourier transform infrared (FTIR) measurements. The XRD patterns confirmed that increasing SiO(2)in semicrystalline PEO enhances the amorphousity and causes a disturbance in the crystalline phase. The influence of the SiO(2)on the dielectric relaxation spectra of PEO in wide temperature and frequency ranges was investigated. Two molecular relaxation processes are observed: main (alpha-) and secondary (beta-) relaxations. For the alpha-process, the process slowed down with adding SiO(2)fillers reflecting an increase in the glass transition temperature,T-g. This trend was also verified by differential scanning calorimetry (DSC). The findings indicated that adding SiO(2)restricted the motion of PEO segments, while such changes were not observed in the glassy state. Further, the attenuation of the electric field of the terahertz waves passed through PEO/SiO(2)samples was evaluated. In the terahertz range, the resonant peaks of PEO originated from lattice vibration feature the complex dielectric function. These peaks were weakened broadened and red-shifted by increasing of SiO(2)concentrations.

Automated summary

Films of polyethylene oxide filled with silicon dioxide were synthesized using the casting method. The addition of SiO2 to PEO increased amorphousity and disrupted the crystalline phase. The dielectric relaxation spectra of PEO were affected by the presence of SiO2, leading to changes in molecular relaxation processes and a decrease in the motion of PEO segments. The terahertz waves passing through PEO/SiO2 samples were also influenced by the presence of SiO2, resulting in weakened, broadened, and red-shifted resonant peaks.