Triboelectric probes for investigating charge transfer at the colloid-solid interface

The charge transfer between the colloid and solid interface is a crucial factor for predicting colloid behavior and rational utilization of colloids. Despite its significance, analyzing the characteristics and subsequent effects of charge transfer at the colloid-solid interface remains challenging due to the complex multiphase nature of colloids. In this study, a liquid-solid triboelectric nanogenerator was used as a probe to detect the interfacial charge transfer during the contact electrification process of colloid-solid. The impact of colloid type, colloidal nanoparticle residue on the solid surface, and colloidal nanoparticle surface charge were investigated. The results indicate that in cases where the colloidal dispersion medium contains an excessive number of ions, ion adsorption dominates the interfacial charge transfer. The generation of hydrated protons after electron transfer between the colloid and solid leads to the deposition of colloidal nanoparticles on the solid surface, inhibiting charge transfer. When the dispersion medium contains fewer free ions and the colloidal nanoparticles possess a hydrophilic surface, the colloidal electric double layer significantly influences the interfacial charge transfer. The findings of this study provide valuable insights and open up new possibilities for further research in understanding the interactions between colloids and solids.