Limits...
Silicon-Based Chemical Motors: An Efficient Pump for Triggering and Guiding Fluid Motion Using Visible Light.

Esplandiu MJ, Farniya AA, Bachtold A - ACS Nano (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Institut Catala de Nanociencia i Nanotecnologia , Campus UAB, 08193 Bellaterra, Barcelona, Spain.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus

(a) Effect of light exposure on patterning the platinum disk with positive particles on p-Si/Pt devices in 1 wt % hydrogen peroxide. The disk on the left side was extensively exposed to the microscope light so that it was completely covered with positive particles. Only few particles settled on the right disk, which was not much exposed to the microscope light. The left disk was exposed with a light intensity that is 8.4 larger than that used to expose the right disk; the ratio in the exposure dose between the left disk and the right disk was 84. (b) Radius of the repulsion band as a function of light intensity when the pump was immersed in a solution of hydrogen peroxide with negatively charged particles.
© Copyright Policy - editor-choice
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4660396&req=5

fig5: (a) Effect of light exposure on patterning the platinum disk with positive particles on p-Si/Pt devices in 1 wt % hydrogen peroxide. The disk on the left side was extensively exposed to the microscope light so that it was completely covered with positive particles. Only few particles settled on the right disk, which was not much exposed to the microscope light. The left disk was exposed with a light intensity that is 8.4 larger than that used to expose the right disk; the ratio in the exposure dose between the left disk and the right disk was 84. (b) Radius of the repulsion band as a function of light intensity when the pump was immersed in a solution of hydrogen peroxide with negatively charged particles.

Mentions: We now show how silicon pumps can be used to manipulate the spatial distribution of particles in the liquid and to pattern particle structures at specific locations on the surface. The image in Figure 5a shows a sample with two platinum disks patterned on the substrate and immersed in a 1% H2O2 solution with positive particles. The platinum disk on the left side was intensively exposed to the microscope light (by zooming the field of view) and was completely covered with P+ particles. Only a few particles settled on the other disk, which was exposed with a much lower dose. This shows that a selective control of particle patterning on specific disks can be achieved by illuminating different locations of the sample.


Silicon-Based Chemical Motors: An Efficient Pump for Triggering and Guiding Fluid Motion Using Visible Light.

Esplandiu MJ, Farniya AA, Bachtold A - ACS Nano (2015)

(a) Effect of light exposure on patterning the platinum disk with positive particles on p-Si/Pt devices in 1 wt % hydrogen peroxide. The disk on the left side was extensively exposed to the microscope light so that it was completely covered with positive particles. Only few particles settled on the right disk, which was not much exposed to the microscope light. The left disk was exposed with a light intensity that is 8.4 larger than that used to expose the right disk; the ratio in the exposure dose between the left disk and the right disk was 84. (b) Radius of the repulsion band as a function of light intensity when the pump was immersed in a solution of hydrogen peroxide with negatively charged particles.
© Copyright Policy - editor-choice
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4660396&req=5

fig5: (a) Effect of light exposure on patterning the platinum disk with positive particles on p-Si/Pt devices in 1 wt % hydrogen peroxide. The disk on the left side was extensively exposed to the microscope light so that it was completely covered with positive particles. Only few particles settled on the right disk, which was not much exposed to the microscope light. The left disk was exposed with a light intensity that is 8.4 larger than that used to expose the right disk; the ratio in the exposure dose between the left disk and the right disk was 84. (b) Radius of the repulsion band as a function of light intensity when the pump was immersed in a solution of hydrogen peroxide with negatively charged particles.
Mentions: We now show how silicon pumps can be used to manipulate the spatial distribution of particles in the liquid and to pattern particle structures at specific locations on the surface. The image in Figure 5a shows a sample with two platinum disks patterned on the substrate and immersed in a 1% H2O2 solution with positive particles. The platinum disk on the left side was intensively exposed to the microscope light (by zooming the field of view) and was completely covered with P+ particles. Only a few particles settled on the other disk, which was exposed with a much lower dose. This shows that a selective control of particle patterning on specific disks can be achieved by illuminating different locations of the sample.

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: Institut Catala de Nanociencia i Nanotecnologia , Campus UAB, 08193 Bellaterra, Barcelona, Spain.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus