Dielectric characterisation and intermolecular interactions in propionitrile-dimethyl sulphoxide mixtures using a time domain reflectometry

Complex permittivity spectra of propionitrile (PN) – dimethyl sulphoxide (DMSO) mixtures in the 10 MHz–30 GHz frequency range were investigated using time-domain reflectometry (TDR). The Debye model was employed to fit the measured dielectric spectra, allowing for the calculation of dielectric parameters like the static dielectric constant (ε0) and relaxation time (τ). Excess dielectric constant (ε0 E) and excess inverse relaxation time (1/τ)E were subsequently calculated from the measured ε0 and τ. The observed variations in these excess parameters provide evidence for intermolecular interactions within the PN-DMSO mixtures. Theoretical estimates of the ε0 were obtained using Luzar's hydrogen-bonded model.