Improved analysis of the effect of chain flexibility on the nematic to smectic-A phase transition

Experimental studies have shown that the chain flexibility plays an important role in the properties of the liquid crystal phase transitions. We examine the effect of the chain flexibility on the nematic to smectic-A phase transition within the Landau phenomenological theory. We show how the flexibility of the chains influences the critical behavior of the nematic to smectic-A phase transition. The possibility of the tricritical point at the nematic to smectic-A phase transition is discussed in a phenomenological way. The theoretical predictions are found to be in good qualitative agreement with available experimental results.