1 research outputs found
Reversed Janus Micro/Nanomotors with Internal Chemical Engine
Self-motile
Janus colloids are important for enabling a wide variety
of microtechnology applications as well as for improving our understanding
of the mechanisms of motion of artificial micro- and nanoswimmers.
We present here micro/nanomotors which possess a reversed Janus structure
of an internal catalytic āchemical engineā. The catalytic
material (here platinum (Pt)) is embedded within the interior of the
mesoporous silica (mSiO<sub>2</sub>)-based hollow particles and triggers
the decomposition of H<sub>2</sub>O<sub>2</sub> when suspended in
an aqueous peroxide (H<sub>2</sub>O<sub>2</sub>) solution. The pores/gaps
at the noncatalytic (Pt) hemisphere allow the exchange of chemical
species in solution between the exterior and the interior of the particle.
By varying the diameter of the particles, we observed size-dependent
motile behavior in the form of enhanced diffusion for 500 nm particles,
and self-phoretic motion, toward the nonmetallic part, for 1.5 and
3 Ī¼m ones. The direction of motion was rationalized by a theoretical
model based on self-phoresis. For the 3 Ī¼m particles, a change
in the morphology of the porous part is observed, which is accompanied
by a change in the mechanism of propulsion <i>via</i> bubble
nucleation and ejection as well as a change in the direction of motion