Interactions of adsorbed poly(ethylene oxide) mushrooms with a bare silica-ionic liquid interface

Oliver Werzer, Rob Atkin

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The interaction of adsorbed poly(ethylene oxide) (PEO) mushrooms with clean silica-ethylammonium nitrate (EAN, a protic ionic liquid) interfaces is investigated using atomic force microscopy (AFM). 10 kDa, 35 kDa and 100 kDa PEO was used to prepare polymer layers ex situ by drop casting from 0.01 wt% EAN solutions. AFM tapping mode measurements of dried, solvent free PEO layers revealed oblate structures, which increase in size with molecular weight. Colloid probe force curve measurements of these surfaces re-solvated with EAN suggest PEO adopts a mushroom morphology, with the interaction range (layer thickness) increasing with molecular weight. Attractive forces on approach and single strand stretching forces on retraction show PEO has a strong affinity for the silica-EAN interface. The single polymer strand stretching forces follow the freely jointed chain model under good solvent conditions. Contour lengths close to the theoretical limits of 120 nm for the 10 kDa, 290 nm for the 35 kDa and 1240 nm for the 100 kDa PEO samples are observed, while fitted Kuhn lengths are small, at 0.14 nm.

Original languageEnglish
Pages (from-to)13479-13485
Number of pages7
JournalPhysical Chemistry Chemical Physics
Volume13
Issue number30
DOIs
Publication statusPublished - 14 Aug 2011
Externally publishedYes

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