Studying the interaction of hydrophobically modified ethoxylated urethane (HEUR) polymers with sodium dodecylsulfate (SDS) in updateft concentrated polymer solutions

JOURNAL OF COLLOID AND INTERFACE SCIENCE

卷:529

Article

Ibrahim, Mervat S.^1,2  Valencony, Jordane¹  King, Stephen³  Murray, Martin⁴  Szczygiel, Agnieszka⁴  Alexander, Bruce D.¹  Griffiths, Peter C.¹ 

[1] Univ Greenwich, Fac Engn & Sci, Medway Campus, Chatham ME4 4TB, Kent, England

[2] Modern Sci & Arts Univ, Fac Pharm, Pharmaceut Dept, 26 July Mehwar Rd,Intersect Wahat Rd, Cairo, Egypt

[3] Sci & Technol Facil Council, Rutherford Appleton Lab, ISIS Facil, Didcot OX11 0QX, Oxon, England

[4] AkzoNobel, Wexham Rd, Slough SL2 5DS, Berks, England

关键词: HEUR;    SDS;    Viscosity;    PGSE-NMR;    Surface tension;    Fluorescence;    EPR;    SANS;    Polymer/surfactant complex;    Telechelic polymers;   

DOI  :  10.1016/j.jcis.2018.06.042

来源: Elsevier

【 摘 要 】

Hypothesis: Hydrophobically modified ethoxylated urethane polymers (HEURs) are widely used to control the rheological profile of formulated particulate dispersions through associative network formation, the properties of which are perturbed by the presence of surfactants. At high polymer concentrations and in the presence of surfactants, it is hypothesised that the dominant factors in determining the rheological profile are the number and composition of the mixed hydrophobic aggregates, these being defined by the number and distribution of the hydrophobic linkers along the polymer backbone, rather than the end group hydrophobe characteristics per se that dominate the low polymer concentration behaviour. Experiments: Three different HEUR polymers with formulae (C-6-L-(EO100-L)(9)-C-6, C-10-L-(EO200-L)(4)-C-10 and C-18-L-(EO200-L)(7)-C-18 (where L = urethane linker, C-n = hydrophobic end-group chain length, and EO = ethylene oxide block) have been studied in the absence and presence of SDS employing techniques that quantify (a) the bulk characteristics of the polymer surfactant blend, (b) the structure and composition of the hydrophobic domains, (c) the dynamics of the polymer and surfactant, and (d) the polymer conformation. Collectively, these experiments demonstrate how molecular-level interactions between the HEURs and sodium dodecylsulfate (SDS) define the macroscopic behaviour of the polymer/surfactant mixture. Findings: Binding of the SDS to the polymer via two mechanisms- monomeric anti-cooperative and micellar cooperative-leads to surfactant-concentration-specific macroscopic changes in the viscosity. Binding of the surfactant to the polymer drives a conformational rearrangement, and an associated redistribution of the polymer end-groups and linker associations throughout the hydrophobic domains. The composition and size of these domains are sensitive to the polymer architecture. Therefore, there is a complex balance between polymer molecular weight, ethylene oxide block size, and number of urethane linkers, coupled with the size of the hydrophobic end-groups. In particular, the urethane linkers are shown to play a hitherto largely neglected but important role in driving the polymer association. (C) 2018 Elsevier Inc. All rights reserved.

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