Intrachain flexibility constraints on phase stabilities and odd-even effects in multiple smectic-A and nematic liquid crystals
The importance of the flexibility of n-alkyl tail chains in real liquid-crystal systems is reviewed. Two new microscopic, molecular statistical-physics theories (a full statistical theory and a simpler but accurate approximate theory) for the intrachain constraints on the n-alkyl tail-chain flexibility are presented and are compared with each other and with an old, more approximate theory for tail-chain flexibility used in earlier papers. The new approximate approach is computationally much faster than the full statistical method and is the first treatment to generate and explain odd-even effects in multiple smectic-A phases and the first treatment to generate and explain odd-even effects in smectic-A and nematic phases without resorting to ad hoc or arbitrarily adjustable fits to experimental data. Phase stabilities and odd-even effects for various thermodynamic and molecular ordering properties are calculated in the smectic-A/sub 1/, smectic-A/sub d/, and nematic liquid-crystal phases and the isotropic liquid phase using the new approximate method. Some predictions and accompanying physical explanations are made for various systems that have not yet been chemically synthesized and/or experimentally studied.
- Research Organization:
- Theoretical Division, Los Alamos National Laboratory, University of California, Los Alamos, New Mexico 87545
- OSTI ID:
- 7160890
- Journal Information:
- Phys. Rev. A; (United States), Vol. 38:1
- Country of Publication:
- United States
- Language:
- English
Similar Records
New theories for smectic and nematic liquid crystalline polymers
Steric molecular theory for multiple smectic-A phases