Ionic effects in self-propelled Pt-coated Janus swimmers

摘要: Colloidal particles partially coated with platinum and dispersed in H2O2 solution are often used as model self-propelled colloids. Most current data suggest that neutral self-diffusiophoresis propels these particles. However, several studies have shown strong ionic effects this related systems, such a reduction of propulsion speed by salt. We investigate Pt-coated polystyrene colloids, find here the direction can be reversed addition an surfactant, although adding pH salts reduces speed, base NaOH has little effect. use data, well measured reaction rates, to argue against either or self-diffusiophoresis, instead particle's mechanism may fact bear close resemblance operative bimetallic swimmers.