In Situ Nanofluid Dispersion Monitoring by Liquid–Solid Triboelectric Nanogenerator Based on Tuning the Structure of the Electric Double Layer

Abstract An agglomeration phenomenon characterized by nanoparticle dispersion is a decisive factor that reflects the degree of the maintained overall performance of nanofluids and other nanocomposites. However, the quantitative characterization and non‐destructive measurement for nanofluid dispersion (NFD) still remain challenged. Herein, an in situ NFD measurement system based on a variable frequency liquid–solid triboelectric nanogenerator (VFLS‐TENG) is developed. This work utilizes VFLS‐TENG as a passive probe and proposes an equivalent capacitance circuit model for detecting NFD based on the electric double layer model at liquid–solid interfaces. In the circuit model, a quantitative calculation process for both particle size and spacing is introduced through parameter identification using the Quantum Genetic and Levenberg–Marquardt hybrid algorithm, and parameter separation using the Runge–Kutta algorithm. The results demonstrates a good agreement with the traditional methods, among which the measured particle size is more accurate than the hydrodynamic diameter of dynamic light scattering by 28.6% with a high sensitivity of 1667 nm nF −1 . The proposed method is capable of measuring the effective charge on the nanoparticle surface in situ, and simultaneously obtaining the particle size and spacing for the online monitoring NFD, thus further facilitating the controllable preparation during the nano‐composites modification, and quantitative optimization of nanofluid design performance.