Microscopic Origin of the Hofmeister Effect in Gelation Kinetics of Colloidal Silica.

摘要: The gelation kinetics of silica nanoparticles is a central process in physical chemistry, yet it not fully understood. Gelation times are measured to increase by over 4 orders magnitude, simply changing the monovalent salt species from CsCl LiCl. This striking effect has no microscopic explanation within current paradigms. trend consistent with Hofmeister series, pointing short-ranged solvation effects included standard colloidal (DLVO) interaction potential. By implementing simple form for short-range repulsion model that relates timescale forces, we able explain many magnitude difference at fixed concentration. allows us estimate non-DLVO hydration which dominate interparticle interactions on length scale hydrated ion diameter. opens possibility finely tuning time just adjusting background electrolyte species.