Authors: Wenjea J Tseng ShinRu Wang
Publish Date: 2007/03/13
Volume: 18, Issue: 3-4, Pages: 197-204
Abstract
Barium titanate BaTiO3 nanoparticles were dispersed in ethanol–isopropanol mixtures and their rheological behaviors were examined in terms of surfactant concentration 0–5 wt of the solids and volumetric solids loading phi = 010 035 over a shearrate mathop gamma limits cdot range 1 to 1000 s−1 An oxyethylenebased polymeric surfactant was used to facilitate the nanoparticle dispersion A pronounced viscosity reduction 95 when compared to the suspensions without the dispersant resulted with a surfactant concentration of 4 wt at a constant shear rate of 100 s−1 This finding was in parallel with a simultaneous reduction in the mean “floc” size of the suspensions Shearthinning flow character resulted over most of the shearrate range examined especially for the concentrated suspensions with ϕ ≥ 025 The concentrated suspensions were indeed flocculated This increased instability was partly due to the compression of electrical double layer as the particulate solids became more crowded in the carrier solvents and also to the increased “effective” solids concentration because of the preferential adsorption of the surfactant molecules on the nanoparticle surfaceFinancial support from the National Science Council Taiwan ROC under contract NSC 922216E005020 and from the Advanced Green Energy Materials Project of the National Chung Hsing University from a special grant of the Ministry of Education are acknowledged
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