Monolayers of colloidal particles at oil-water interfaces readily crystallize owing to electrostatic repulsion, which is often mediated through the oil. However, little attempts exist to control it using oil -soluble electrolytes. We probe the interactions among charged hydrophobic microspheres confined at a water-hexadecane interface and show that repulsion can be continuously tuned over orders of magnitude upon introducing nanomolar amounts of an organic salt into the oil. Our results are compatible with an associative discharging mechanism of surface groups at the particle-oil interface, similar to the charge regulation observed for charged colloids in nonpolar solvents.
Tuning Electrostatic Interactions of Colloidal Particles at Oil-Water Interfaces with Organic Salts / van Baalen, Carolina; Vialetto, Jacopo; Isa, Lucio. - In: PHYSICAL REVIEW LETTERS. - ISSN 0031-9007. - ELETTRONICO. - 131:(2023), pp. 128202-128202. [10.1103/physrevlett.131.128202]
Tuning Electrostatic Interactions of Colloidal Particles at Oil-Water Interfaces with Organic Salts
Vialetto, Jacopo;
2023
Abstract
Monolayers of colloidal particles at oil-water interfaces readily crystallize owing to electrostatic repulsion, which is often mediated through the oil. However, little attempts exist to control it using oil -soluble electrolytes. We probe the interactions among charged hydrophobic microspheres confined at a water-hexadecane interface and show that repulsion can be continuously tuned over orders of magnitude upon introducing nanomolar amounts of an organic salt into the oil. Our results are compatible with an associative discharging mechanism of surface groups at the particle-oil interface, similar to the charge regulation observed for charged colloids in nonpolar solvents.I documenti in FLORE sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.