Salt-free catanionic surface active ionic liquids 1-alkyl-3-methylimidazolium alkylsulfate: Aggregation behavior in aqueous solution
| Autor: | Min Liu, Bing Han, Ni Cheng, Jingjing Jiao, Li Yu, Meijia Lin |
|---|---|
| Rok vydání: | 2013 |
| Předmět: |
chemistry.chemical_classification
Aqueous solution Chemistry Inorganic chemistry Cationic polymerization Surfaces Coatings and Films Electronic Optical and Magnetic Materials Gibbs free energy Biomaterials Surface tension chemistry.chemical_compound symbols.namesake Colloid and Surface Chemistry Polymer chemistry Amphiphile Ionic liquid symbols Molecule Alkyl |
| Zdroj: | Journal of Colloid and Interface Science. 412:24-30 |
| ISSN: | 0021-9797 |
| Popis: | A series of salt-free catanionic surface active ionic liquids (SAILs), 1-alkyl-3-methylimidazolim alkyl sulfates (denoted as [Cnmim][CmSO4], n=6, 8, 10; m=12 and n=4; m=10, 14) were synthesized by an ion exchange reaction and their surface properties in aqueous solution were examined systematically by surface tension, fluorescence and electrical conductivity measurements. As catanionic surfactants, these SAILs exhibit notably higher surface activity, compared to the cationic or anionic analogues. Increment in both cationic and anionic alkyl chain lengths for [Cnmim][CmSO4] can both improve the amphiphilic character remarkably. This can be ascribed to cooperative interactions as formation of catanionic pairs between alkyl-substituted imidazolium cations and alkyl sulfate anions. The negative micellization Gibbs free energy values prove that the micellization of all the 1-alkyl-3-methylimidazolim alkyl sulfates investigated is a spontaneous process. Any additional CH2 group makes the micellization process easier regardless if it is on a cation or an anion. When keeping the total carbon atom number constant, we find that the [Cnmim][CmSO4] molecules with greater asymmetric alkyl chains display superior surface activity. This work indicates that the self-assembly of these imidazolium-based salt-free catanionic SAILs can be tailored by adjusting the mismatch of alkyl chains. These SAILs are expected to have potential applications in the fields of colloidal and interface and nanomaterial synthesis. |
| Databáze: | OpenAIRE |
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