Functional macroporous amphoteric polyelectrolyte monoliths with tunable structures and properties through emulsion-templated synthesis

• Published in: Journal of colloid and interface science Vol. 575; pp. 480 - 488
• Main Authors: Jurjevec, Sarah, Žagar, Ema, Kovačič, Sebastijan
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 01-09-2020
• Subjects: Amphoteric polyelectrolyte; Oil-in-water HIPEs; Poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS); Poly(3-acrylamidopropyl)trimethylammonium chloride (PAMPTMA); Quenched polyampholytes; Amphoteric polyelectrolyte; Poly(2-acrylamido-2-methyl-1-propanesulfonic acid) (PAMPS); Quenched polyampholytes; Oil-in-water HIPEs; Poly(3-acrylamidopropyl)trimethylammonium chloride (PAMPTMA)
• ISSN: 0021-9797; 1095-7103
• DOI: 10.1016/j.jcis.2020.05.016

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•A new templated-synthesis through “HIPE mixtures” is reported.•Two pre-formed emulsions based on oppositely charged monomers were combined.•Amphoteric polyelectrolyte monoliths exhibit 'anti-polyelectrolyte' behaviour.•The performance in the dye mixture adsorption was examined.•Complete removal of all dyes carrying different charges at the same time was found.
Macroporous polyampholyte hydrogels, simultaneously bearing both the anionic and cationic groups, demonstrate immense promise over the one-sign charged polyelectrolytes, owing to a unique phenomenon known as the ˝anti-polyelectrolyte˝ effect. Thus, they are extremely promising materials, since they remain solvated and functional even in harsh conditions. Furthermore, macroporous morphology significantly enhances polyampholyte response to external stimuli, since it accelerates the solvent transport through the hydrogel.
A new templated-synthesis through “HIPE mixtures” is reported, where the two pre-formed high internal phase emulsions (HIPE) containing the oppositely charged monomers (2-acrylamido-2-methyl-1-propanesulfonic acid and (3-acrylamidopropyl)trimethylammonium chloride) were combined in the same mould, which after polymerization result in the formation of macroporous monoliths of different structures. The resulting frameworks were either copolymer or dual homopolymers in the form of bilayered or mixed porous structures.
The co– and mixed-amphoteric polyelectrolytes exhibit 'anti-polyelectrolyte' behaviour typical of polyampholytes, while the bilayered-structure behaves like a typical polyelectrolyte. Complete and simultaneous removal of both dyes from a dye mixture was observed for the bilayered- and mixed-amphoteric polyelectrolyte, while copoly-ampholyte showed only partial dye adsorption. These results clearly reveal the benefits of a mutual combination of the HIPE-templated structure and the oppositely charged amphoteric nature in one-piece material as a promising avenue toward advanced materials.