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

E-Jen Teh, Yee-Kwong Leong, Xianwei Zhang, Hong Fan, Yang Gan, Thomas Becker

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

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.

Original languageEnglish
Pages (from-to)1765-1777
Number of pages13
JournalCOLLOID AND POLYMER SCIENCE
Volume294
Issue number11
Early online date12 Sep 2016
DOIs
Publication statusPublished - 1 Nov 2016

Fingerprint Dive into the research topics of 'Hydrophobic interaction and patch charge attraction in α-Al<sub>2</sub>O<sub>3</sub> 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'. Together they form a unique fingerprint.

  • Cite this