Glass transition temperature thermotropic liquid crystal polymer

Both polymer melts and polymer solutions sometimes form phases with orientational and positional ordci. Thermotropic polymer liquid crystals possess at least one liquid crystal phase between the glass-transition temperature and the transition temperature to the isotropic liquid. Lyotropic polymer liquid crystals possess at least one liquid cry stal phase for certain ranges of concentration and temperature. 

In some polymer liquid crystals, several mesophases can be identified. In main-chain liquid crystal polymers there is usually a transition from the crystal to a mesophase, whereas in more amorphous systems when a glass transition is present, the mesophase may appear after this transition has occurred. In multiple transition thermotropic systems, the increase in temperature leads to changes from the most-ordered to the least-ordered states, i.e., crystal (k) smectic (S) nematic (N) isotropic (i). 

The thermotropic polymer liquid crystals possess at least one liquid crystalline phase between glass-transition temperature and transition temperature to isotropic liquid. Similarly under certain ranges of temperatures and concentrations, lyotropic polymer liquid crystalline materials possess at least one liquid crystalline phase. Of course some polymers may exhibit both thermotropic and lyotropic behavior. 

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