Search

Stability of engineered nanomaterials within natural aquatic systems is generally difficult to predict due to multiple roles that background electrolytes may play in these suspensions. Here we utilize core shell nanoparticles based on random copolymers of di(ethylene glycol) methyl ether methacrylate ( x = MEO 2 MA) and oligo(ethylene glycol) methyl ether methacrylate ( y = OEGMA) to investigate specific ion effects on colloidal stability. Aggregation kinetics ( k 11 ) of Au@(MEO 2 MA x -co-OEGMA y ) NPs were measured for KCl, NaCl, SrCl 2 , and MgCl 2 at various concentrations by means of time-resolved dynamic light scattering (TR-DLS). It was found that the smallest concentration of K + and the greatest concentration of Mg 2 + were required to increase the aggregation rate. Specifically, we demonstrate k 11 scales not only as a result of ionic strength, but also in some cases in a direction opposite to that expected by the Schultz–Hardy rule. For these systems, aggregation kinetics can be better predicted by ion characterization within the well-established Hofmeister series.