Self-diffusiophoresis of chemically active colloids

Abstract

Abstract. Chemically active colloids locally change the chemical composition of their solvent via catalytic reactions which occur on parts of their surface. They achieve motility by converting the released chemical free energy into mechanical work through various mechanisms, such as phoresis. Here we discuss the theoretical aspects of self-diffusiophoresis, which -despite being one of the simplest motility mechanisms -captures many of the general features characterizing self-phoresis, such as self-generated and maintained hydrodynamic flows "driven" by surface activity induced inhomogeneities in solution. By studying simple examples, which provide physical insight, we highlight the complex phenomenology which can emerge from self-diffusiophoresis.

Floor- or Ceiling-Sliding for Chemically Active, Gyrotactic, Sedimenting Janus Particles

“…10,11,19,25). This leads to collisions with the ceiling, which is a prerequisite for the emergence of a sliding state; 15,23,42 obviously, in this regime of chemical activity the sliding states at the floor cease to exist. The issue is whether the above lift-off scenario is actually a necessary condition for the occurrence of a sliding state at the ceiling.…”

Chemotactic and hydrodynamic effects on collective dynamics of self-diffusiophoretic Janus motors

“…The strength and direction of chemotactic and hydrodynamic interactions among motors in a suspension depend on their relative orientations since concentration and flow fields are induced by catalytic reactions taking place on specific parts of the motor surfaces; consequently, motor morphology plays a role in determining the dynamical properties of active suspensions. The effects of the size of the catalytic patch on the dynamics of a single Janus motor in bulk [40] or near a wall [41] and on the interactions between two motors [42] have been studied using continuum theory.…”

Microswimmers – From Single Particle Motion to Collective Behavior

“…First technical realizations of self-propelled objects have been developed for different driving mechanisms and conversion strategies. The fundamental driving mechanisms as well as state-of-the-art technologies of artificial microswimmers are covered in several minireviews [8][9][10][11][12][13].…”