Autocatalytic colloid suspensions in the presence of a liquid-liquid interface

Abstract

Self-propelled diffusiophoretic colloids are currently being studied because of its revolutionary way to solve real applications on fields such as water cleaning or medicine. One of the most considered prototypes is the Pt-silica Janus because of its simplicity and easy construction. Although today Janus can be built within hours, still it lacks some physical knowledge of their behaviour. In an attempt to understand better Janus, in this project I have performed not only an experimental but also a computational approach to Janus. In particular, I have focus on what happens for Pt-silica Janus in a dilute regime near a liquid-liquid interface. Experimental results have shown how the velocity is decreased compared to its usual velocity on bulk up to 45%. Moreover, interface modifications with surfactants has also shown how on the one hand, surfactants interfere in Janus velocity but also, how Janus are further to the interface. Computational results, could not approximate as much as experimental, but at least they show how Janus can be modelled and how this model could explain real behaviour of Janus at the bulk by selecting a small region for chemorepellant mobility parameters related to each of the parts of the Janus particle