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June 12, 2006Great Lakes Photonics
Symposium 2006
Liquid Crystalline Elastomers
Jeremy Neal Liquid Crystal Institute - Kent State University
Kent, OH
Work supported by NSF-EC DMR 0132611
June 12, 2006Great Lakes Photonics
Symposium 2006
Liquid Crystal Elastomers
liquid crystal unit
rubber backbone
cross-linker
• LCE: liquid crystal rubber
•Conventional rubberrubber backbone
cross-linker
June 12, 2006Great Lakes Photonics
Symposium 2006
LCE Composition
Si O
CH3
H
O C
O
O OCH3
O
O
O
O C
O
O
CH3
CH3
CH3
CH3
CH3
n
9
9
9
1
2
3
4
100 mol.%
72 mol.%
18 mol.%
10 mol.%
Si O
CH3
H
O C
O
O OCH3
O
O
O
O C
O
O
CH3
CH3
CH3
CH3
CH3
n
9
9
9
1
2
3
4
100 mol.%
72 mol.%
18 mol.%
10 mol.%
Si O
CH3
H
O C
O
O OCH3
O
O
O
O C
O
O
CH3
CH3
CH3
CH3
CH3
n
9
9
9
1
2
3
4
100 mol.%
72 mol.%
18 mol.%
10 mol.%
Si O
CH3
H
O C
O
O OCH3
O
O
O
O C
O
O
CH3
CH3
CH3
CH3
CH3
n
9
9
9
1
2
3
4
100 mol.%
72 mol.%
18 mol.%
10 mol.%
• Rubber backbone (main chain)
• Liquid crystalline unit (side group)
• Crosslinker
Si O
CH3
H
O C
O
O OCH3
O
O
O
O C
O
O
CH3
CH3
CH3
CH3
CH3
n
9
9
9
1
2
3
4
100 mol.%
72 mol.%
18 mol.%
10 mol.%
Si O
CH3
H
O C
O
O OCH3
O
O
O
O C
O
O
CH3
CH3
CH3
CH3
CH3
n
9
9
9
1
2
3
4
100 mol.%
72 mol.%
18 mol.%
10 mol.%
June 12, 2006Great Lakes Photonics
Symposium 2006
Elastomer Shape Changes
HeatingL
L
WW
June 12, 2006Great Lakes Photonics
Symposium 2006
Light Induced Bending of LCEs
• laser illumination causes the elastomer to bend towards the beam, as shown
Sample
ArLaser
1.5 cm
June 12, 2006Great Lakes Photonics
Symposium 2006
Elastomer Fish
LabVIEW
• switchable mirror allows alternate illumination of each side of LCE sample
Switchable Mirror Elastomer
Fish(3 x 6 mm)
MirrorArgon Laser
shutter
June 12, 2006Great Lakes Photonics
Symposium 2006
Elastomer Fish• sample immersed in rheoscopic fluid, which allows for flow visualization
• sample is illuminated alternately on both sides by light at 514nm from Ar laser
June 12, 2006Great Lakes Photonics
Symposium 2006
Another Elastomer Fish
Shape changes propagate like a wave down the sample causing it to swimaway from the light.
June 12, 2006Great Lakes Photonics
Symposium 2006
Conclusions
• LCEs add a LC component to a conventional rubber
• LCEs have unique properties
• Many potential applications for LCEs
• Need more research for commercialization
