Viscosity decoupled charge transport in surface functionalized ZnS nanoparticle dispersed imidazolium ionanofluids

The mechanism of charge transport in ionic liquid functionalized ZnS nanoparticles dispersed imidazolium-based ionanofluids are investigated combining impedance spectroscopy, viscosity measurement and diff;erential scanning calorimetry. The viscosity enhances from 76 mPa S to 229 mPa S at room temperature in 0-20 wt% of functionalised nanoparticles addition in the ionic liquid. The conductivity and permittivity spectra are dominated on the low-frequency side by electrode polarization effects. Using the Poisson-Nernst-Planck (PNP) electro-diffusion equations enables us to determine the dc conductivity, ion diffusivity and hopping length of mobile ions and their nature of thermal activation. A decoupling of ion transport with viscosity is observed in the ionanofluids within the entire temperature range and for the 15.0 wt% nanoparticle inserted nanofluid conductivity reaches a maximum value (2.5 mS/cm at 30 degrees C). The physical explanation regarding the possible origin of the observed remarkable decoupling is proposed.