Abstract
The potential for manipulation and control inherent in molecule-based motors holds great scientific and technological promise. Molecules containing the azobenzene group have been heavily studied in this context. While the effects of the cis-trans isomerization of the azo group in such molecules have been examined macroscopically by a number of techniques, modulations of the elastic modulus upon isomerization in self-assembled films were not yet measured directly. Here, we examine the mechanical response upon optical switching of bis[(1,1'-biphenyl)-4-yl]diazene organized in a self-assembled film on Au islands, using atomic force microscopy. Analysis of higher harmonics by means of a torsional harmonic cantilever allowed real-time extraction of mechanical data. Quantitative analysis of elastic modulus maps obtained simultaneously with topographic images show that the modulus of the cis-form is approximately twice that of the trans-isomer. Quantum mechanical and molecular dynamics studies show good agreement with this experimental result, and indicate that the stiffer response in the cis-form comprises contributions both from the individual molecular bonds and from intermolecular interactions in the film. These results demonstrate the power and insights gained from cutting-edge AFM technologies, and advanced computational methods.
| Original language | English |
|---|---|
| Pages (from-to) | 834-844 |
| Number of pages | 11 |
| Journal | Beilstein Journal of Nanotechnology |
| Volume | 2 |
| Issue number | 1 |
| DOIs | |
| Publication status | Published - 1 Dec 2011 |
| Externally published | Yes |
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Keywords
- AFM
- Azobenzene
- Elastic modulus
- Molecular dynamics
- Nanomechanics
- Photoswitch
- Quantum mechanics computation
- Self-assembled monolayer
ASJC Scopus subject areas
- Materials Science(all)
- Physics and Astronomy(all)
- Electrical and Electronic Engineering
Cite this
Direct monitoring of opto-mechanical switching of self-assembled monolayer films containing the azobenzene group. / Tirosh, Einat; Benassi, Enrico; Pipolo, Silvio; Mayor, Marcel; Valásek, Michal; Frydman, Veronica; Corni, Stefano; Cohen, Sidney R.
In: Beilstein Journal of Nanotechnology, Vol. 2, No. 1, 01.12.2011, p. 834-844.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Direct monitoring of opto-mechanical switching of self-assembled monolayer films containing the azobenzene group
AU - Tirosh, Einat
AU - Benassi, Enrico
AU - Pipolo, Silvio
AU - Mayor, Marcel
AU - Valásek, Michal
AU - Frydman, Veronica
AU - Corni, Stefano
AU - Cohen, Sidney R.
PY - 2011/12/1
Y1 - 2011/12/1
N2 - The potential for manipulation and control inherent in molecule-based motors holds great scientific and technological promise. Molecules containing the azobenzene group have been heavily studied in this context. While the effects of the cis-trans isomerization of the azo group in such molecules have been examined macroscopically by a number of techniques, modulations of the elastic modulus upon isomerization in self-assembled films were not yet measured directly. Here, we examine the mechanical response upon optical switching of bis[(1,1'-biphenyl)-4-yl]diazene organized in a self-assembled film on Au islands, using atomic force microscopy. Analysis of higher harmonics by means of a torsional harmonic cantilever allowed real-time extraction of mechanical data. Quantitative analysis of elastic modulus maps obtained simultaneously with topographic images show that the modulus of the cis-form is approximately twice that of the trans-isomer. Quantum mechanical and molecular dynamics studies show good agreement with this experimental result, and indicate that the stiffer response in the cis-form comprises contributions both from the individual molecular bonds and from intermolecular interactions in the film. These results demonstrate the power and insights gained from cutting-edge AFM technologies, and advanced computational methods.
AB - The potential for manipulation and control inherent in molecule-based motors holds great scientific and technological promise. Molecules containing the azobenzene group have been heavily studied in this context. While the effects of the cis-trans isomerization of the azo group in such molecules have been examined macroscopically by a number of techniques, modulations of the elastic modulus upon isomerization in self-assembled films were not yet measured directly. Here, we examine the mechanical response upon optical switching of bis[(1,1'-biphenyl)-4-yl]diazene organized in a self-assembled film on Au islands, using atomic force microscopy. Analysis of higher harmonics by means of a torsional harmonic cantilever allowed real-time extraction of mechanical data. Quantitative analysis of elastic modulus maps obtained simultaneously with topographic images show that the modulus of the cis-form is approximately twice that of the trans-isomer. Quantum mechanical and molecular dynamics studies show good agreement with this experimental result, and indicate that the stiffer response in the cis-form comprises contributions both from the individual molecular bonds and from intermolecular interactions in the film. These results demonstrate the power and insights gained from cutting-edge AFM technologies, and advanced computational methods.
KW - AFM
KW - Azobenzene
KW - Elastic modulus
KW - Molecular dynamics
KW - Nanomechanics
KW - Photoswitch
KW - Quantum mechanics computation
KW - Self-assembled monolayer
UR - http://www.scopus.com/inward/record.url?scp=84855535294&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=84855535294&partnerID=8YFLogxK
U2 - 10.3762/bjnano.2.93
DO - 10.3762/bjnano.2.93
M3 - Article
AN - SCOPUS:84855535294
VL - 2
SP - 834
EP - 844
JO - Beilstein Journal of Nanotechnology
JF - Beilstein Journal of Nanotechnology
SN - 2190-4286
IS - 1
ER -