Difference between revisions of "Assembly of optical-scale dumbbells into dense photonic crystals"

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UNDER CONSTRUCTION
 
UNDER CONSTRUCTION
  
[[Image:Dufresne_photonic_crystal_1.gif|thumb|400px|right| Figure 1, reproduced from [1]. Explanation.]]
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[[Image:Dufresne_photonic_crystal_1.gif|thumb|400px|right| Figure 1, reproduced from [1]. Dumbbell colloids crystallize in thin films, but not in the bulk. SEM images. (a) Dumbbells cast in thin films. (b) Dumbbells cast into a thick film.]]
[[Image:Dufresne_photonic_crystal_2.gif|thumb|400px|right| Figure 2, reproduced from [1]. Explanation.]]
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[[Image:Dufresne_photonic_crystal_2.gif|thumb|400px|right| Figure 2, reproduced from [1]. Dumbbells in solution crystallize in AC electric fields.  Shows the emergence of structural color and birefringence as a function of time after electric field is turned on (top row) and off (bottom row).]]
 
[[Image:Dufresne_photonic_crystal_3.gif|thumb|400px|right| Figure 3, reproduced from [1]. Explanation.]]
 
[[Image:Dufresne_photonic_crystal_3.gif|thumb|400px|right| Figure 3, reproduced from [1]. Explanation.]]
 
[[Image:Dufresne_photonic_crystal_4.gif|thumb|400px|right| Figure 4, reproduced from [1]. Explanation.]]
 
[[Image:Dufresne_photonic_crystal_4.gif|thumb|400px|right| Figure 4, reproduced from [1]. Explanation.]]

Revision as of 07:41, 13 November 2012

Original Entry: Stephen Fleming, AP 225, Fall 2012

UNDER CONSTRUCTION

Figure 1, reproduced from [1]. Dumbbell colloids crystallize in thin films, but not in the bulk. SEM images. (a) Dumbbells cast in thin films. (b) Dumbbells cast into a thick film.
Figure 2, reproduced from [1]. Dumbbells in solution crystallize in AC electric fields. Shows the emergence of structural color and birefringence as a function of time after electric field is turned on (top row) and off (bottom row).
Figure 3, reproduced from [1]. Explanation.
Figure 4, reproduced from [1]. Explanation.

General Information

Authors: JD Forster, J Park, Manish Mittal, H Noh, CF Schreck, CS O'Hern, H Cao, EM Furst, and ER Dufresne

Publication: JD Forster, J Park, Manish Mittal, H Noh, CF Schreck, CS O'Hern, H Cao, EM Furst, and ER Dufresne. (2011) "Assembly of optical-scale dumbbells into dense photonic crystals." ACS Nano 5 (8), pp. 6695-6700.

Access to paper from ACS Publications

Keywords: Thin film, Self assembly

Summary

Dumbbell-shaped colloidal particles can be made to assemble into crystals in the presence of an external AC electric field. These crystal structures can have long-range order, and they exhibit photonic band gaps and birefringence.


Background

Colloids with anisotropic interactions are sometimes called "colloidal molecules." The entire phase space of self-assembly of such colloidal molecules has not been fully explored. However, there have been many numerical simulations. For dumbbell-shaped particles, such simulations indicate that the aspect ratio is very important for determining the phase behavior.

The self-assembly of dumbbells without external fields cannot produce large-scale structures, since such assembly can only take place in thin films.


Explanation of Experimental Methods

Results

Discussion

Reference

[1] JD Forster, J Park, Manish Mittal, H Noh, CF Schreck, CS O'Hern, H Cao, EM Furst, and ER Dufresne. (2011) "Assembly of optical-scale dumbbells into dense photonic crystals." ACS Nano 5 (8), pp. 6695-6700.