liquid crystal elastomer response to light
DESCRIPTION
Liquid Crystal Elastomer Response to Light. Rafael Soares Zola CPIP-LCI Advisor: Peter Palffy-Muhoray. Objectives. Observe the response of the Liquid Crystal Elastomer (LCE) to a source of light; Understand the key features of the Spatial Light Modulator (SLM); - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/1.jpg)
Liquid Crystal Elastomer Response to Light
Rafael Soares Zola
CPIP-LCI
Advisor: Peter Palffy-Muhoray
![Page 2: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/2.jpg)
Objectives Observe the response of the Liquid Crystal
Elastomer (LCE) to a source of light;
Understand the key features of the Spatial Light Modulator (SLM);
Use the SLM as a dynamic element;
Apply light with intensity varying with position and time on the sample;
![Page 3: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/3.jpg)
Background
Liquid Crystal Elastomer*: Rubber and Liquid Crystal!
Doped
oo o
o
azo dye Disperse Orange III
Si
CH3
H
O
85
Si
CH3
CH3
HSi
CH3
O
CH3
Ho
CH2
o
CH2
Backbone Mesogen Cross-Linker (12%)
4.0mm
7.5mm
*M. Camacho-Lopez, et al Nature Materials 3, 307 (2004).
n̂
![Page 4: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/4.jpg)
Background
Change in the degree of order: cis-trans transition (Azo Dye) temperature
The free energy of the elastomer
2 2 3 41 1
2
1
2 4
1
3F aQ bQ cQYe Qe
rubber liquid crystal coupling term
![Page 5: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/5.jpg)
Background
SLM:
Twisted Nematic cell used as dynamic element in experimental setups
![Page 6: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/6.jpg)
Background
Computer Image
Laser through
Transmissive SLM
Number of pixels:832 x 624
Pixel pitch: 32m
Image frame rate: max. 60Hz
Active area: 26.6mm x 20.0mm
![Page 7: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/7.jpg)
Capability of SLM
![Page 8: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/8.jpg)
Background Intensity vs. gray level:
0 50 100 150 200 250 300
0
50
100
150
200
250
300In
tensi
ty (W
)
gray level
![Page 9: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/9.jpg)
Setup
Camera
Computer
AnalyzerLens
Mirror
Sample
Polarizer
Argon Laser
- CW
- =514nm
Filter 514nm
![Page 10: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/10.jpg)
Setup
Sample
SLM
Camera
Microscope Objective
![Page 11: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/11.jpg)
Results
Ppump=15mW
![Page 12: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/12.jpg)
Results
Ppump=15mW
ttransition= 10s
![Page 13: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/13.jpg)
Results
Ppump=43.73mWttransition= 10s
![Page 14: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/14.jpg)
Conclusions
The SLM can be used to control the intensity over the sample spatially and temporally
This control allows one to move the LCE in some specific manner
Coordinated movements depends on accurate control of the beam over the sample
![Page 15: Liquid Crystal Elastomer Response to Light](https://reader036.vdocument.in/reader036/viewer/2022062500/5681572a550346895dc4c440/html5/thumbnails/15.jpg)
Acknowledgements
Especial Thanks for:
Dr. Michele Moreira (muito obrigado mesmo!!)
Jake Fontana
Jeremy Neal