Salting-in effect of ionic liquids on poly(N-vinylimidazole) hydrogels

• Published in: Colloid and polymer science Vol. 291; no. 8; pp. 2017 - 2021
• Main Authors: Renamayor, Carmen S., Pastoriza, Alejandra, Usma, Cesar L., Pierola, Ines F.
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01-08-2013; Springer; Springer Nature B.V
• Subjects: Applied sciences; Characterization and Evaluation of Materials; Chemistry; Chemistry and Materials Science; Chlorides; Complex Fluids and Microfluidics; Electrolytes; Exact sciences and technology; Food Science; Hydrogels; Immersion; Interaction parameters; Ionic liquids; Nanotechnology and Microengineering; Organic polymers; Physical Chemistry; Physicochemistry of polymers; Polymer Sciences; Properties and characterization; Short Communication; Soft and Granular Matter; Solution and gel properties; Sorption; Swelling; Ionic liquids; Cross-linked polymer; Poly; Salting-in effect; vinylimidazole; Polymer–solvent interaction parameter; Imidazole derivatives; Swelling; Iminium compounds; Polymer-solvent interaction parameter; Sodium chloride; Experimental study; Ionic liquid; Colloidal gel; Salt effect; Ionic strength; Imidazole(vinyl) polymer; Poly(N-vinylimidazole); Kinetics; Thermodynamic properties; Mineral salt; Interaction parameter
• ISSN: 0303-402X; 1435-1536
• DOI: 10.1007/s00396-013-2937-6

This work attempts to study the interaction of two ionic liquids (1-ethyl-3-methylimidazolium tosylate and 1-hexyl-3-methylimidazolium chloride) with chemically crosslinked poly(
N
-vinylimidazole) in aqueous media, and to compare it with that of NaCl, a typical salting-out electrolyte. The three salts show a salting-in effect whose intensity was measured on the basis of the decrease of the polymer–solvent interaction parameter and the increase of swelling with increasing ionic strength. It was thus found that the salting-in effect is the same for the two salts with the same anion (chloride), while the intensity of the salting-in effect exerted by the tosylate ionic liquid is larger. The coefficient of selective sorption, which expresses the salt excess inside the swollen gel with respect to the external solution was determined by comparing the initial and equilibrium compositions of the immersion bath. These results are discussed in terms of the hydrophobic character of the ions involved.