Effect of sequentially adsorbed multilayers, citric acid(CA)-PEI-CA-PEI and PEI-CA-PEI-CA, on the surface chemistry and rheology of spherical α-alumina suspensions

Wei Zhang, Yee Kwong Leong, Chunbao Sun, Hong Fan, Xianwei Zhang

Research output: Contribution to journalArticlepeer-review

3 Citations (Scopus)

Abstract

The yield stress and zeta potential of washed spherical α-Al2O3 suspensions with two to four layers of critic acid(CA) and polyethyleneimine(PEI_Mw1.8and 70 kDa) adsorbed sequentially were characterized. With CA adsorbed as the first layer, pHξ=0 was shifted to a lower pH and the maximum yield stress (τymax) was reduced. With PEI adsorbed as the first layer, the pHξ=0 was moved slightly higher. With the introduction of the second layer, the CA/PEI additive was formed which functioned as a bridging agent. The pH range of yield stress was broadened significantly and increased with the number of layers. This pH ranged from 2.5 to 11. The CA/PEI multilayer additive loses its positive charge at pH >11. There was less adsorption in layer3 and layer4 when lower Mw PEI is applied to the suspension. The CA/PEI multilayer additive formed by PEI of Mw70000 and CA was larger in size than that formed by PEI of Mw 1800 and CA. Lower Mw PEI produced a stronger flocculated network or higher τymax suspension due to a higher concentration of multilayer additive. CA/PEI multilayer additive was participating in bridging and particle bridging interaction was not affected by the adsorption order of CA and PEI.GRAPHICAL ABSTRACT (Figure presented.).

Original languageEnglish
Pages (from-to)1179-1188
Number of pages10
JournalJournal of Dispersion Science and Technology
Volume40
Issue number8
DOIs
Publication statusPublished - 3 Aug 2019

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