Measurement of inter-particle Hamaker constants in mineral materials using atomic force microscopy

The Hamaker constant is essential for quantifying particles interactions; however, its study has been limited due to technical constraints. While atomic force microscopy (AFM) can measure probe-to-particle surface interaction forces, it cannot directly measure particle-to-particle interaction forces. To address this issue, this paper introduces an AFM-based test method to quantify the interaction force between particles and a new approach for calculating the Hamaker constant. Using these methods, the particle-to-particle Hamaker constants of cement and fly ash in various environments were investigated. Results showed that adhesion values followed a log-normal distribution and that both adhesion and Hamaker constants varied significantly between materials. The measured Hamaker constants of different mineral materials ranged from 22.79 to 38.26 × 10⁻²⁰ J in air and from 4.79 to 14.47 × 10⁻²⁰ J in water, with material properties and testing environment identified as primary influencing factors.