Compact poly(ethylene oxide) structures adsorbed at the ethylammonium nitrate-silica interface

Oliver Werzer, Gregory G. Warr, Rob Atkin

Research output: Contribution to journalArticle

23 Citations (Scopus)

Abstract

The adsorption of poly(ethylene oxide) (PEO) and poly(propylene oxide) (PPO) onto silica from ethylammonium nitrate (a protic ionic liquid) has been investigated using colloid probe AFM force curve measurements. Steric repulsive forces were measured for PEO, confirming that PEO can compete with the ethylammonium cation and adsorb onto silica. The range of the repulsion increases with polymer molecular weight (e.g., from 1.4 nm for 0.01 wt % 10 kDa PEO to 40 nm for 0.01 wt % 300 kDa PEO) and with concentration (e.g., from 16 nm at 0.001 wt % to 78 nm at 0.4 wt % for 300 kDa PEO). Fits to the force curve data could not be obtained using standard models for a polymer brush, but excellent fits were obtained using the mushroom model, suggesting the adsorbed polymer films are compressed and relatively poorly solvated. No evidence for adsorption of 3.5 kDa PPO could be detected up to its solubility limit.

Original languageEnglish
Pages (from-to)3541-3549
Number of pages9
JournalLangmuir
Volume27
Issue number7
DOIs
Publication statusPublished - 5 Apr 2011
Externally publishedYes

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