Mechanical rotor-bearing model for liquid crystal systems

The liquid crystal phases are postulated as a mechanical rotor-bearing syst em in which liquid crystal molecular core and terminals are estimated as th e rotor and axes, respectively, the terminals also function as molecular ro tors in the subsequent layers. Some general rules are proposed that relate phase stability to molecular structures and the mechanical rotor-bearing mo del is applied to explain the phase behaviors. Phenomena of the thermal sta bility of phase and phase transition are explained in terms of basic mechan ical and dynamical parameters: center of gravity, eccentricity, moment of i nertia and mass distribution. Fluorination effects on liquid crystallinity are explained in a uniform manner by mechanical and dynamical basis. Moreov er, we have also examined interesting liquid crystalline systems such as li quid crystal oligomers. Characteristic thermal behaviors are correlated to the molecular structures and their mechanical or dynamical parameters to co mplete validity of the model proposed.