The relationship between microstructure changes and rheological properties in suspensions containing boehmite particles, which are well applied in various industrial wash-coating processes, was investigated by changing pH condition. The boehmite particles in suspensions were either well dispersed or aggregated depending on the pH, owing to the relative contributions of repulsive interaction between particles as well as hydrolysis and condensation reactions. Four groups of boehmite suspensions were classified as very low, intermediate, almost zero charge, and high pH regimes based on their colloidal behaviors, and their microstructural differences were investigated using transmission electron microscopy (TEM) and multi-speckle diffusing wave spectroscopy (MSDWS). For gel-like suspensions of three groups, various rheological properties such as shear viscosity, viscoelastic modulus, yield stress, and recovery behavior were extensively compared, and the results clearly demonstrated that a suspension with high yield stress was not fully recovered into the original state when disturbed at high shear rates.
Bibliographical noteFunding Information:
This study was supported by the Ministry of Trade, Industry, and Energy (MOTIE, Korea) under the Industrial Technology Innovation Program (No. 20011712) and by National Research Foundation of Korea (NRF) grants funded by the Ministry of Science and ICT (MSIT) of the Korean government (No. NRF-2016R1A5A1009592 and NRF-2021M3H4A6A01041234).
© 2022, Korean Society of Rheology.
- Boehmite suspension
- Microstructural change
- Particle motion
- Yield stress
ASJC Scopus subject areas
- Materials Science(all)
- Condensed Matter Physics