Dispersion state and rheology of hectorite particles in water over a broad range of salt and particle concentrations |
| |
Authors: | Hiroshi Kimura Mikito Sakurai Taiki Sugiyama Akira Tsuchida Tsuneo Okubo Toru Masuko |
| |
Institution: | (1) Department of Chemistry and Graduate School of Materials Science, Gifu University, 1-1 Yanagido, Gifu 501-1193, Japan;(2) Institute for Colloidal Organization, 3-1-112 Hatoyama, Uji, Kyoto 611-0012, Japan;(3) Graduate School of Science and Technology, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510, Japan;(4) Department of Polymer Science and Engineering, Yamagata University, 4-3-16 Jonan, Yonezawa 992-8510, Japan |
| |
Abstract: | The relationship between the rheological properties of deionized aqueous suspensions of hectorite particles and the dispersion
states of the particles has been studied with a broad range of salt and particle concentrations. The shear viscosity of the
hectorite suspensions decreases drastically after exhaustively deionizing the suspensions with ion-exchange resins. By means
of DLS measurements, it is clarified that the average size of the flocs of hectorite particles decreases and reaches the Stokes
diameter of the individual particle as the degree of deionization advances. This fact strongly supports the idea that the
electrical double layer around the hectorite particles expands significantly in the exhaustively deionized state and the particles
are well-dispersed individually and do not form a three-dimensional network structure composed of particles, whereas such
a network structure forms in the presence of a large amount of salt. In the case of exhaustively deionized state, the suspension
forms a glassy state, at high particle fractions. The results show the importance of the electrical double layer that causes
a strong repulsive force among the particles on the particle dispersion state, especially in the exhaustive deionization area
below 10 − 4 M, and on the rheological properties; the hectorite suspension can be considered a Newtonian liquid in the deionized state,
but it becomes elastic-solid in the presence of salt above a certain concentration confirmed by normal stress measurements. |
| |
Keywords: | |
本文献已被 SpringerLink 等数据库收录! |
|