Hydrophobic interaction and patch charge attraction in α-Al2O3 dispersions under the influence of adsorbed low molecular-weight polyacrylic acid sodium salt and poly(methacrylic acid) sodium salt: yield stress and AFM force study
MetadataShow full item record
© 2016, Springer-Verlag Berlin Heidelberg.Maximum yield stress data showed that low molecular-weight (Mw) (~7 kDa) poly(methacrylic acid) sodium salt (PMA-Na) additive at low surface coverage displayed significant patch charge attraction in contrast to polyacrylic acid sodium salt (PAA-Na) additive of similar Mw and surface coverage. Intramolecular hydrophobic interaction between CH3 groups in the polymer molecule during adsorption produced a much more compact patch with a higher negative charge density giving rise to the stronger patch charge attraction. At high surface coverage, intermolecular hydrophobic interaction between CH3 groups on the adsorbed layer of the interacting particles was not observed from maximum yield stress data. Such interaction was, however, observed in AFM force-distance characterization data for interaction between spherical alumina particles and sapphire plates coated with PMA-Na in retraction mode. The compression of the adsorbed layers at contact during the approach mode was postulated to deform and breakup the intramolecular interaction between the CH3 groups and promoted intermolecular interaction between these groups in the layer coating the particle and plate. This resulted in a strong adhesion force seen in the retraction mode after contact at low pH near the point of zero charge.
Showing items related by title, author, creator and subject.
Kirwan, Luke J. (2002)For the majority of tailings substrates, flocculant adsorption proceeds through hydrogen bonding of the amide functionalities with neutral surfaces. However, flocculation of Bayer process residue solids takes place in ...
Rossiter, Angelina Jane (2009)Due to the ductile nature of the sodium nitrate crystal which deforms plastically under high levels of strain, most of the crystal growth studies in aqueous solution have focussed on the influence of tensile strain, ...
Size exclusion chromatography as a tool for natural organic matter characterisation in drinking water treatmentAllpike, Bradley (2008)Natural organic matter (NOM), ubiquitous in natural water sources, is generated by biogeochemical processes in both the water body and in the surrounding watershed, as well as from the contribution of organic compounds ...