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Silicon-Based Chemical Motors: An Efficient Pump for Triggering and Guiding Fluid
Motion Using Visible Light
#MMPMID26349036
Esplandiu MJ
; Farniya AA
; Bachtold A
ACS Nano
2015[Nov]; 9
(11
): 11234-40
PMID26349036
show ga
We report a simple yet highly efficient chemical motor that can be controlled
with visible light. The motor made from a noble metal and doped silicon acts as a
pump, which is driven through a light-activated catalytic reaction process. We
show that the actuation is based on electro-osmosis with the electric field
generated by chemical reactions at the metal and silicon surfaces, whereas the
contribution of diffusio-osmosis to the actuation is negligible. Surprisingly,
the pump can be operated using water as fuel. This is possible because of the
large ?-potential of silicon, which makes the electro-osmotic fluid motion
sizable even though the electric field generated by the reaction is weak. The
electro-hydrodynamic process is greatly amplified with the addition of reactive
species, such as hydrogen peroxide, which generates higher electric fields.
Another remarkable finding is the tunability of silicon-based pumps. That is, it
is possible to control the speed of the fluid with light. We take advantage of
this property to manipulate the spatial distribution of colloidal microparticles
in the liquid and to pattern colloidal microparticle structures at specific
locations on a wafer surface. Silicon-based pumps hold great promise for
controlled mass transport in fluids.
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