Abstract
We have investigated the molecular alignment and the phase transition behavior in a mixture of a typical thermotropic smectic liquid crystal [4-(methylheptyloxycarbonyl) phenyl 4'-octyloxybihenyl-4-carboxylate:MHPOBC] and a chain-like molecule [such as octane and hexane]. Myelin texture was observed in polarized microscopy of the mixture in the temperature region where the mesophases were confirmed in the DSC thermogram. A typical smectic X-ray image was also observed in temperature dependent X-ray measurements, which revealed that the layer thickness abruptly increased at the phase transition temperature from crystal to smectic. In addition, quadrupolar splitting was observed in 2H-NMR spectra of the chain-like molecule, because it was ordered in the smectic phase. Accordingly, not only the liquid-crystalline molecule but also the chain-like molecule took part in the architecture of the smectic structure appearing in the mixture.
