Vitrified chiral-nematic liquid crystalline films for selective reflection and circular polarization
- Univ. of Rochester, NY (United States)
- Eastman Kodak Co., Rochester, NY (United States)
Nematic and left-handed chiral-nematic liquid crystals comprising methoxybiphenylbenzoate and (S)-(-)-1-phenylethylamine pendants to a cyclohexane core were synthesized and characterized. Although pristine samples were found to be polycrystalline, thermal quenching following heating to and annealing at elevated temperatures permitted the molecular orders characteristic of liquid crystalline mesomorphism to be frozen in the glassy state. Left at room temperature for 6 months, the vitrified liquid crystalline films showed no evidence of recrystallization. An orientational order parameter of 0.65 was determined with linear dichroism of a vitrified nematic film doped with Exalite 428 at a mole fraction of 0.0025. Birefringence dispersion of a blank vitrified nematic film was determined using a phase-difference method complemented by Abbe refractometry. A series of vitrified chiral-nematic films were prepared to demonstrate selective reflection and circular polarization with a spectral region tunable from blue to the infrared region by varying the chemical composition. The experimentally measured circular polarization spectra were found to agree with the Good-Karali theory in which all four system parameters were determined a priori: optical birefringence, average refractive index, selective reflection wavelength, and film thickness.
- Sponsoring Organization:
- National Science Foundation, Washington, DC (United States); Department of the Air Force, Washington, DC (United States); USDOE, Washington, DC (United States); New York State Energy Research and Development Authority, Albany, NY (United States)
- DOE Contract Number:
- FC03-92SF19460
- OSTI ID:
- 682130
- Journal Information:
- Chemistry of Materials, Vol. 11, Issue 6; Other Information: PBD: Jun 1999
- Country of Publication:
- United States
- Language:
- English
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