Silicon-based chemical motors : an efficient pump for triggering and guiding fluid motion using visible light
Esplandiu Egido, Maria José (Institut Català de Nanociència i Nanotecnologia)
Afshar Farniya, Ali (Institut Català de Nanociència i Nanotecnologia)
Bachtold, Adrian (Institut de Ciències Fotòniques)

Data:	2015
Resum:	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 ζ-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.
Ajuts:	European Commission 279278 Ministerio de Economía y Competitividad MAT2012-31338
Drets:	Aquest document està subjecte a una llicència d'ús Creative Commons. Es permet la reproducció total o parcial, la distribució, la comunicació pública de l'obra i la creació d'obres derivades, sempre que no sigui amb finalitats comercials, i sempre que es reconegui l'autoria de l'obra original.
Llengua:	Anglès
Document:	Article ; recerca ; Versió publicada
Matèria:	Catalytic motors ; Electro-hydrodynamic forces ; Chemomechanical actuation ; Photoactivation
Publicat a:	ACS nano, Vol. 9, Issue 11 (Nov. 2015) , p. 11234-11240, ISSN 1936-086X

DOI: 10.1021/acsnano.5b04830
PMID: 26349036

7 p, 3.2 MB

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