The document summarizes an experiment investigating the effect of carbon nanotubes on the chirality of liquid crystals. Researchers prepared liquid crystal cells by coating glass with an alignment polymer and dispersing carbon nanotubes in the liquid crystal. They observed that the addition of carbon nanotubes induced chirality in the liquid crystal, even though the liquid crystal on its own was non-chiral. Further experiments ruled out the possibility of impurities or artifacts causing the effect. The researchers concluded that the carbon nanotubes were able to transfer their own intrinsic chirality to the liquid crystal.

1. KRYSTA BOCCUZZI, RAJ BASU, CHARLES ROSENBLATT Effect of Carbon Nanotubes on Chirality in Liquid Crystals

2. Outline Introduction to Liquid Crystals and Carbon Nanotubes Method 8S5 and Carbon Nanotubes Could this be the result of an artifact? Conclusions

3. Introduction to Liquid Crystals Nematic Smectic A Smectic C A liquid crystal is chiral when the mirror image of the molecule cannot be superimposed on the molecule. Liquid crystals have properties between those of liquids and solids.

4. Introduction to Carbon Nanotubes The liquid crystal anchors at the surface of the carbon nanotubes. The axis of the nanotube aligns along the director.

5. The Electroclinic Effect 𝜽 The electroclinic effect only occurs when the liquid crystal is chiral.

6. Cell Preparation Indium Tin Oxide (ITO) coated glass was spin coated with RN1175. The liquid crystal and nanotube mixture was made by dispersing the nanotubes in acetone, shaking them in a vortex mixer for 15 minutes, and sonicating them for 2 hours. The cell was filled in the nematic phase and cooled to the Smectic A phase. ITO coating alignment polymer glass rubbing direction rubbing direction

7. Experimental set-up Laser Polarizer (22.5° from director) Analyzer Lens Sample Detector Digital Multimeter Lock-in Amplifier Function generator Computer

8. 8S5 and Carbon Nanotubes

9. Could this be the result of an artifact? Chemical analysis by the manufacturer showed no chiral impurities. Washed in acetone. Washed in toluene.

10. Conclusions The carbon nanotubes transfer chirality to the liquid crystal. Future work will focus on finding the cause of this chirality.