Water-based latex dispersions 4.

Exchange dynamics and residence times of nonylphenol ethoxylate in concentrated latex dispersions

Catherine Boissier*, Jan-Erik Löfroth, Magnus Nydén, Staffan Schantz

*Corresponding author for this work

Research output: Contribution to journalArticle

1 Citation (Scopus)

Abstract

The equilibrium residence times of the nonionic surfactant nonylphenol ethoxylate (NP100) in a latex dispersion were determined using NMR diffusometry. At 16% w/w particle concentration and 0.12, 0.43 and 0.81% w/w NP100, the residence times of the surfactant were 0.16, 1.02 and 4.73 s in solution (τA) and 0.3, 0.37 and 0.61 s on the surface of the particles (τB), respectively. At even higher particle concentration (>45% w/w), τA and τB were 1.47 and 2.2 s. Calculating the number of collisions that ought to result in adsorbed species, at 16% w/w, only 2, 5 and 2‰ (corresponding to 0.12, 0.43 and 0.81% w/w NP100) resulted in adsorption, whereas at >45% w/w, only 12‰ resulted in adsorption, which suggested that the surfactant was irreversibly adsorbed on the particles. The small increase in collision frequency with increased particle concentration could be a result of a diffusion controlled adsorption, while an energy barrier for desorption controlled the overall exchange dynamics in the dispersion. The slow dynamics in the dispersion was controlled, mainly by the nonylphenol group, which gave NP100 a strong preference to surfaces. In addition, the chain length of the poly(ethylene glycol) (PEG) group changed the solution behavior from being that of a typical surfactant to that of a polymer.

Original languageEnglish
Pages (from-to)63-70
Number of pages8
JournalJournal of Colloid and Interface Science
Volume292
Issue number1
DOIs
Publication statusPublished - 1 Dec 2005
Externally publishedYes

Keywords

  • Dispersion
  • Exchange dynamics
  • NMR
  • Nonionic surfactant
  • Relaxation
  • Residence times
  • Self-diffusion

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