Nanomechanical actuation using molecular forces of amino azo benzene dye
Abstract/Contents
- Abstract
- The emerging fields of nanomotors and optomechanics are based on the harnessing of light to generate force. However, our ability to detect the changes in material properties as a result of these forces (such as small surface stresses) is limited by temperature drift, environmental noise, and low-frequency flicker electronic noise. To addresses these limitations, we functionalized microfabricated silicon cantilevers with an azo dye, silane- based self-assembled monolayer. We developed a fast, one pot, simple, room-temperature linkage chemistry to connect methyl red (the actuator) to 3-aminopropyltriethoxysilane (a silicon attachment) to form (E)-2-((4-(dimethylamino)phenyl)diazenyl) -N- (3(triethoxysi- lyl)propyl)benzamide (MR-APTES). These molecules change their shape when exposed to light at specific wavelengths, enabling modulation of surface stress by light. Atomicforcemicroscopy, contactangleanalysis, ellipsometry, andX-rayphotoelectron spectroscopy verified successful assembly of molecules on the cantilever. Ultraviolet and visible spectra demonstrated optical switching of the synthesized molecule in solution. MR-APTES was then used to form a self assembled monolayer (1 nm thick) on surface ofasiliconcantileverof500µmlong100µmwideand1µmthick. Theoptical-mechanical actuation of cantilever surface stress was observed by exciting the MR-APTES with a 405 nm laser and optically monitoring tip deflection, allowing us to measure forces of approximately 0.3 pN per molecule. Cantilever tip deflection (3 nm) was measured with a Witec alpha atomic force microscope. By turning the laser on and off at a specific rate (1 Hz), we measured cantilever tip deflection via Fourier techniques, thus separating the signal of interest from the noise. This technique, which is similar to electronic lock-in techniques empowers the design of highly sensitive chemical sensors and forms the basis of a new class of nanomechanical actuators.
Description
| Type of resource | text |
|---|---|
| Form | electronic; electronic resource; remote |
| Extent | 1 online resource. |
| Publication date | 2014 |
| Issuance | monographic |
| Language | English |
Creators/Contributors
| Associated with | Rastegar, A. Joseph |
|---|---|
| Associated with | Stanford University, Department of Mechanical Engineering. |
| Primary advisor | Melosh, Nicholas A |
| Primary advisor | Pruitt, Beth |
| Thesis advisor | Melosh, Nicholas A |
| Thesis advisor | Pruitt, Beth |
| Thesis advisor | Howe, Roger Thomas |
| Advisor | Howe, Roger Thomas |
Subjects
| Genre | Theses |
|---|
Bibliographic information
| Statement of responsibility | A. Joseph Rastegar. |
|---|---|
| Note | Submitted to the Department of Mechanical Engineering. |
| Thesis | Thesis (Ph.D.)--Stanford University, 2014. |
| Location | electronic resource |
Access conditions
- Copyright
- © 2014 by Ali Joseph Rastegar
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