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From Molecules to Materials: Engineering New Ionic Liquid Crystals Through Halogen Bonding
Published on: March 24, 2018
Surface characterization of functionalized imidazolium-based ionic liquids
Claudia Kolbeck1, Manuela Killian, Florian Maier
1Lehrstuhl fur Physikalische Chemie II, Department Chemie and Pharmazie, Friedrich-Alexander-Universitat Erlangen-Nurnberg, Egerlandstrasse 3, 91058 Erlangen, Germany.
Langmuir : the ACS Journal of Surfaces and Colloids
|August 5, 2008
Summary
X-ray photoelectron spectroscopy confirmed high purity and no surface orientation effects in functionalized ionic liquids. Surface-active impurities were detected in the starting material, [Me(EG)MIM]I.
Area of Science:
- Materials Science
- Surface Chemistry
- Ionic Liquids
Background:
- Oligo(ethylene glycol) ether functionalized bis(trifluoromethylsulfonyl)imide ionic liquids are advanced materials with potential applications.
- Understanding their surface composition is crucial for predicting their behavior and performance.
Purpose of the Study:
- To investigate the surface composition of novel ionic liquids with varying ethylene glycol chain lengths.
- To determine if surface orientation effects or impurities are present in these ionic liquids.
Main Methods:
- X-ray photoelectron spectroscopy (XPS) was employed to analyze the surface composition.
- Angle-resolved XPS was used to probe both bulk and surface-sensitive regions.
- Comparison of elemental stoichiometry between bulk and surface was performed.
Main Results:
- For [Me(EG)MIM][Tf 2N], [Et(EG) 2MIM][Tf 2N], and [Me(EG) 3MIM][Tf 2N], surface stoichiometry closely matched bulk stoichiometry, indicating high purity.
- No significant surface orientation effects were observed for the studied ionic liquids.
- Surface-active impurities were identified in the precursor [Me(EG)MIM]I, which exhibited surface enrichment.
Conclusions:
- The investigated functionalized ionic liquids ([Me(EG)MIM][Tf 2N], [Et(EG) 2MIM][Tf 2N], [Me(EG) 3MIM][Tf 2N]) are highly pure with no pronounced surface orientation.
- Impurities in precursor materials can lead to surface-active contamination, necessitating careful synthesis and purification protocols.
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