Entropically driven reentrant SmC-SmA-SmC phase transition in composite   polymer--liquid crystal systems
  I consider the effects of polymers on the smectic phase of a host liquid crystal matrix. Focusing on the regime in which the polymers are predominately confined between the smectic layers, I find that the presence of the polymers can lead to a reentrant phase diagram with the smectic-C sandwiching the smectic-A phase from both the high and low temperature sides. Simple entropy-energy arguments predict the shape of the reentrant phase boundary. 
Leo Radzihovsky