Form factor rodlike molecule

Figure 2 5. Form factor P(k) for a spherical molecule, a rodlike molecule, and a Gaussian chain, plotted as a function of kR. ...

The terms liquid crystal and mesophase are interchangeable. Meso, in Greek, means between , so a fluid can be called a mesophase if it has some properties that are characteristic of crystals. The ability of the fluid to form a liquid crystal is due to the molecules ability to align with each other and create local ordering. So, liquid crystalline polymers are those polymers that form liquid crystalline phases either in solution or in the melt. Molecules that form a mesophase are usually rod-like or disc-like. In the case of rodlike polymers, such as poly(p-phenyleneterephthalamide) (PPTA), the rigidity of the backbone is primarily responsible for the formation of a mesophase. The rigidity is, of course, dependent on a variety of factors such as the nature of the solvent used, the temperature of the solution, and the chemical structure of the molecule. 

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