Influence of polycation/cation competition
on the aggregation threshold of magnetic nanoparticles - Archive ouverte HAL Accéder directement au contenu
Article Dans Une Revue Colloids and Surfaces A: Physicochemical and Engineering Aspects Année : 2020

Influence of polycation/cation competition
on the aggregation threshold of magnetic nanoparticles

Résumé

Precise control of the aggregation of magnetic nanoparticles in aqueous environment is a key to their successful application in the biological and medical fields. We investigate here the critical aggregation threshold of PAA-coated maghemite nanoparticles in aqueous solution, in the presence of ionenes, polycations with a regular, tunable and pH-insensitive chain charge density, and a variety of ammonium-based salts. Aggregation of the nanoparticles is followed by a combination of dynamic light scattering and light absorbance measurements, along a dilution pathway from initially dispersed systems at high salt concentration (3M). The position of the aggregation threshold, or critical salt concentration, is found to depend on two parameters: volume of the salt cation (V cation) and volume of the charged monomer unit of the polycation (V mono + , reflecting the polycation charge density). Combining these two parameters, a master curve emerges, showing that the critical salt concentration follows in a linear fashion the ratio of the above two volumes, V cation /V mono +. Interpreted within the theory of Collins and coworkers, the master curve is a clear demonstration of the importance of local ion-pairing in governing the stability of the system, which remains unaccounted for in the continuum electrostatic theories attempting to describe polyelectrolyte complex formation. Moreover, such a master curve provides a very simple rule for the control of interactions between charged polyelectrolytes moderated by salts.
Fichier principal
Vignette du fichier
Demirelli_accepted_FINAL.pdf (1.74 Mo) Télécharger le fichier
Origine : Fichiers produits par l'(les) auteur(s)

Dates et versions

hal-03058032 , version 1 (11-12-2020)

Identifiants

Citer

Mesut Demirelli, Véronique Peyre, Juliette Sirieix-Plénet, Natalie Malikova, Jérôme Fresnais. Influence of polycation/cation competition
on the aggregation threshold of magnetic nanoparticles. Colloids and Surfaces A: Physicochemical and Engineering Aspects, 2020, pp.125876. ⟨10.1016/j.colsurfa.2020.125876⟩. ⟨hal-03058032⟩
51 Consultations
97 Téléchargements

Altmetric

Partager

Gmail Facebook X LinkedIn More