Faster in-plane switching and reduced rotational viscosity characteristics in a graphene-nematic suspension
- Soft Matter and Nanomaterials Laboratory, Department of Physics, The United States Naval Academy, Annapolis, Maryland 21402 (United States)
The in-plane switching (IPS) for a nematic liquid crystal (LC) was found to be considerably faster when the LC was doped with dilute concentrations of monolayer graphene flakes. Additional studies revealed that the presence of graphene reduced the rotational viscosity of the LC, permitting the nematic director to respond quicker in IPS mode on turning the electric field on. The studies were carried out with several graphene concentrations in the LC, and the experimental results coherently suggest that there exists an optimal concentration of graphene, allowing a reduction in the IPS response time and rotational viscosity in the LC. Above this optimal graphene concentration, the rotational viscosity was found to increase, and consequently, the LC no longer switched faster in IPS mode. The presence of graphene suspension was also found to decrease the LC's pretilt angle significantly due to the π-π electron stacking between the LC molecules and graphene flakes. To understand the π-π stacking interaction, the anchoring mechanism of the LC on a CVD grown monolayer graphene film on copper substrate was studied by reflected crossed polarized microscopy. Optical microphotographs revealed that the LC alignment direction depended on monolayer graphene's hexagonal crystal structure and its orientation.
- OSTI ID:
- 22596970
- Journal Information:
- Journal of Applied Physics, Vol. 119, Issue 18; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 0021-8979
- Country of Publication:
- United States
- Language:
- English
Similar Records
Effects of graphene on electro-optic switching and spontaneous polarization of a ferroelectric liquid crystal
Effect of surface viscosity, anchoring energy, and cell gap on the response time of nematic liquid crystals
Related Subjects
GENERAL PHYSICS
75 CONDENSED MATTER PHYSICS
SUPERCONDUCTIVITY AND SUPERFLUIDITY
CHEMICAL VAPOR DEPOSITION
COPPER
CRYSTAL STRUCTURE
DOPED MATERIALS
ELECTRIC FIELDS
ELECTRONS
FASTENING
FILMS
GRAPHENE
INTERACTIONS
LIQUID CRYSTALS
MICROSCOPY
SUBSTRATES
SUSPENSIONS
SWITCHES
VISCOSITY